ASSESSMENT OF THE ROBUSTNESS OF THE BIOFIL TOILET
TECHNOLOGY FOR THE TREATMENT OF BLACKWATER
By
Lakachew Yihunie Alemneh
(BSc)
A Thesis Submitted to the Department of Civil Engineering, Kwame Nkrumah University of Science and Technology in Partial Fulfilment of the Requirements for the Degree of
MASTER OF SCIENCE in Water Supply and Environmental Sanitation
Department of Civil Engineering
College of Engineering
JULY, 2014 Certification
I hereby declare that this submission is my own work towards the MSc and that to, the best of my knowledge, it contains no material previously published by another person nor material which has been accepted for the award of any degree of the University, except where due acknowledgement has been made in the text.
Lakachew Yihunie Alemneh (PG771612) ...... (Student name and ID) Signature Date
Certified By:
Dr. (Mrs): Helen M. K. Essandoh ……………….. ………………... (Supervisor) Signature Date Dr.Richard Buamah ...... (Co-Supervisor) Signature Date
Prof. Mohammed Salifu ...... (Head of Dept., Civil Engineering) Signature Date
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Acknowledgement
To God be the glory, great things he has done. All thanks to God almighty who saw me through this experience and made the completion of this research work possible.
Secondly is to my supervisors Dr. (Mrs.) Helen M.K. Essandoh and Dr. Richard Buamah for their kind advice and supervision during my MSc research phase. Really, your dedication to your students and how you have supported me throughout the course of this research work, your commitment as well as your valuable comments has aided my proper understanding of the study and rightfully directed me towards achieving the set research objectives of this study.
My profound gratitude also goes to Peter Owusu for his immeasurable contribution towards the completion of this research work. Your constant willingness and speedy response to the call for assistance throughout the course of the study is really appreciated.
Organizations and people who have helped and supported me throughout this study are also appreciated. First to my sponsors, Bill & Melinda Gates Foundation (BGMF) and the
Netherlands Government through UNESCO-IHE Institute for Water Education which is one of the world leading training institutions with vast international experience. I am grateful to all of them for granting me this scholarship to pursue the Masters degree in Sanitary Engineering.
My sincere gratitude also goes to the lab technicians, Mr. Emmanuel Botwe and Mr. Kingsley
Osei Bonsu during all aspects of the laboratory undertakings. Especially Mr. Emmanuel Botwe was always available to provide all the necessary laboratory resources and advice needed for carrying out my lab work. I really appreciated every moment.
I specially dedicate this last part to my adorable family, for their ever loving advice, support in all kind and encouragement. Also for the thought that, they always believe in me.
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Abstract
As black water management is a problem in the densely populated urban poor communities due to the limited space and the high generation of excreta without effective technologies for treatment and its reduction; the Biofil Toilet Technology (BTT) has been developed to help solve the problem. BTT works by enhancing the symbiotic work of both micro and macro-organisms (earthworms) to treat blackwater. Extensive use of bactericidal household chemicals for cleaning of toilet rooms may affect the activity of the earthworms and hence it was necessary to test resistance of earthworms towards such chemicals for the optimization of the technology.
In this study chloroxylenol (dettol) with concentrations [0.3-5 mg/ml], sodium hypochlorite (parazone) concentrations [0.6-9 mg/ml] and lactic acid (Mr. Muscle) concentrations of [0.7-7 mg/ml] were selected for the test based on the frequent use of these chemicals by the urban and peri urban community householders in Ghana.
The results obtained showed that earthworms were able to survive up to 25% when exposed to chloroxylenol (dettol) without any 100% lethal effect; however, earthworms were not able to resist the effect of sodium hypochlorite (parazone) with 2.5 mg/ml concentration and 7 mg/ml concentration of lactic acid (Mr.Muscle) which caused 100% mortality effect over the 21 days of exposure time. After 7 days of exposure, due to the toxicity effect of various concentrations of the three test chemicals, the earthworms showed body weight loss of 28.5% and relatively low contaminant removal potential. Up to37% COD, 30% BOD, 53% TDS and 54% TSS removals were recorded. However, after 14 days of exposure and onwards, the earthworms were able to recover from the toxicity effect and started to increase their body weight by about 38.7%. Furthermore, during this time the earthworms were able to remove the COD up to 86%; BOD up to 89%; TDS up to 92% and TSS 94% from blackwater in the biofil toilet technology. 4.5 log and 4.6 log removals of pathogenic pollutants namely; E. coli , total coliforms were achieved. Moreover, 87% Helminth ova removal was attained by earthworms in the BTT.
In conclusion increase in the concentrations of the tested chemicals increased toxicity to earthworms which resulted in some mortality, body weight loss and low removal of contaminants but the survived earthworms after a longer exposure (14 to 21 days) could increase in their body weight as well as efficiency in the removal of contaminants.
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Table of Contents
Certification ...... ii Acknowledgement ...... iii Abstract ...... iv Table of Contents ...... v List of Tables ...... viii List of Figures ...... ix List of Abbreviations ...... x Definition of Terms ...... xi CHAPTER ONE ...... 1 1.0. INTRODUCTION ...... 1 1.1. Background ...... 1 1.2. Problem Statement ...... 3 1.3. Research Questions ...... 4 1.4. Research Aim and Objectives ...... 4 1.5. Justification ...... 5 1.6. Scope of the Study ...... 5 1.7 Organization of the Thesis ...... 6 CHAPTER TWO ...... 7 2.0. LITERATURE REVIEW ...... 7 2.1. Introduction ...... 7 2.2. Faecal Matter Characteristics and Composition ...... 9 2.2.1. Daily Excretion of Urine and Faeces ...... 10 2.3. Faecal Matter Treatment Problems ...... 11 2.4. Back Ground of the Development of Biofil Toilet Technology ...... 12 2.4.1. Current Biofil Toilet Technology Application for Blackwater Treatment ...... 14 2.5. Vermicomposting Technology ...... 17 2.6. Earthworms and Their Effect for Soil Conditioning ...... 18 2.6.1. Introduction ...... 18 2.6.2. Effects of Earthworms for Soil Conditioning ...... 19 2.7. Environmental Conditions for Survival and Growth of Earthworms ...... 20 2.7.1. Temperature ...... 20 2.7.2. Hydrogen Ion Level (pH) ...... 20 2.7.3. Moisture Content ...... 21
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2.7.4. Aeration ...... 21 2.8. Breeding, Biology and Classification of Earthworms ...... 22 2.8.1 Life Cycle of Earthworms ...... 22 2.8.1.1. Cocoon Phase ...... 22 2.8.1.2. Juvenile Phase ...... 23 2.8.1.3. Non-Clitellates Phase ...... 23 2.8.1.4. Clitellates Phase ...... 23 2.8.2. Biology of Earthworms ...... 24 2.8.3. Classification of Earthworms ...... 25 2.8.4. Earthworm Species Suitable for Sludge Stabilization ...... 26 2.8.4.1. Eudrilus Eugeniae (Kinberg-1867) ...... 26 2.8.4.2. Eisenia Fetida (Savigny 1826) and Eisenia andrei (Bouché 1972) ...... 27 2.8.4.3. Perionyx Excavatus (Perrier 1872) ...... 27 2.9. Ecotoxicology of Earthworms ...... 28 2.9.1. Introduction ...... 28 2.9.2. Toxicity Tests on Earthworms ...... 29 2.9.3. The Fate of Household Chemicals on On-site Sanitation systems ...... 31 2.9.3.1. Chloroxylenol (dettol) ...... 32 2.9.4.2. Sodium Hypochlorite (Parazone) ...... 33 2.9.4.3. Lactic acid (Mr. Muscle) ...... 34 CHAPTER THREE ...... 36 3.0. RESEARCH METHODOLOGY ...... 36 3.1. Introduction ...... 36 3.2. Collection and Identification of Earthworms ...... 36 3.3. Description of Test chemicals ...... 37 3.3.1. Test Chemical Concentrations ...... 38 3.4. General Description of Experimental Set up and Feed ...... 39 3.4.1. Experimental Procedures ...... 41 3.5 .Statistical Analysis ...... 42 CHAPTER FOUR ...... 44 4.0. RESULTS AND DISCUSSIONS ...... 44 4.1. RESULTS ...... 44 4.1.1. Characteristics of Blackwater ...... 44
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4.1.2. Survival of Earthworm ( eudrilus eugeniae ) ...... 46 4.1.2.1. Effect of Chloroxylenol (dettol) on Eudrilus eugeniae ...... 46 4.1.2.2. Effect of Sodium Hypochlorite (parazone) on Eudrilus eugeniae ...... 47 4.1.2.3. Effect of Lactic acid (Mr Muscle) on Eudrilus eugeniae ...... 48 4.1.3. Earthworm ( eudrilus eugeniae ) Recovery Potential ...... 50 4.1.3.1. Body Weight Change ...... 50 4.1.3.2. Characteristics of Biosolids and Contaminant Removal by Earthworms ...... 52 4.1.3.3. Pathogen Removal ...... 55 4.1.3.4. Chemical Oxygen Demand (COD) removal ...... 60 4.1.3.5. Biological Oxygen Demand (BOD) Removal ...... 62 4.1.3.6. Total Dissolved Solids (TDS) Removal ...... 65 4.1.3.7. Total Suspended Solids (TSS) Removal ...... 67 4.2. DISCUSIONS ...... 70 4.2.1. Characteristics of the Experimental Feed ...... 70 4.2.2. Physico-Chemical Characteristics of the Feed ...... 70 4.2.3. Microbiological Characteristics of the Feed ...... 71 4.2.4. Survival Rates of Earthworms ( eudrilus eugeniae ) ...... 71 4.2.4.1. Effect of Chloroxylenol solution (Dettol) on Eudrilus eugeniae ...... 72 4.2.4.2. Effect of Sodium Hypochlorite (parazone) on Eudrilus eugeniae ...... 73 4.2.4.3. Effect of Lactic acid (Mr. Muscle) on Eudrilus eugeniae ...... 74 4.2.5. Recovery Potential of Earthworms (Eudrilus eugeniae ) ...... 74 4.2.5.1. Body Weight Change ...... 75 4.2.5.2. Performance of Contaminant Removal under Test Conditions ...... 77 CHAPTER FIVE ...... 86 5.0. CONCLUSIONS AND RECOMMENDATIONS ...... 86 5.1. CONCLUSION ...... 86 5.2. RECOMMENDATION ...... 88 REFERENCES ...... 89 INTERNET SOURCES ...... 96 APPENDICES ...... 97
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List of Tables
Table 2-1: Excreta and Urine Generation Rate Per Person in Different Countries ...... 11 Table 2-2: Physical and Chemical Properties of Chloroxylenol (dettol) ...... 32 Table 2-3: Physical and Chemical properties of Sodium Hypochlorite (parazone) ...... 34 Table 2-4: Physical and chemical properties of Lactic acid (Mr. Muscle) ...... 35 Table 3-1: List of Applied Concentrations ...... 39 Table 4-1: Characteristics of Blackwater ...... 45 Table A-1: Earthworms Survival Potential after Exposure of Various Concentrations of Chloroxylenol (dettol).Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 Days of Exposure ..... 97 Table A-2: Body Weight Change of Earthworms Exposed to Chloroxylenol (dettol), Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 days of exposure...... 98 Table A-3: Characteristics and Nutrient Contents of Biosolids Produced by Earthworms Exposed to Chloroxylenol (dettol), Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 Days of Exposure...... 99 Table A-4: Pathogen Contents in the Biosolids Produced by Earthworms Exposed to Chloroxylenol (dettol), Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 Days of Exposure. . 100 Table A-5: COD, BOD, TDS and TSS Contents in the Biosolids Produced by Earthworms Exposed to Chloroxylenol (dettol), Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 Days of Exposure...... 101
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List of Figures
Figure 2-1: The Biofil Toilet Technology ...... 15 Figure 2-2: The Biofil Tiolet Separate Digester (A) The Internal View of the Digester (B) ...... 16 Figure 2-3: Schematic Design of the Biofil Toilet Technology ...... 17 Figure 2-4 Schematic diagram of the Life Cycle of Earthworm ...... 22 Figure 3-1: Culturing of Earthworms ( eudrilus eugenaie ) ...... 37 Figure 3-2: The Dimension of a Single Vermibed Box ...... 40 Figure 3-3: The Schematic Diagram of the Set up ...... 41 Figure 4-1: Percentage Distribution of Helminth ova in RawBlackwater ...... 46 Figure 4-2: Effect of Chloroxylenol on Eudrilus eugeniae Survival after 7 Days ...... 46 Figure 4-3: Effect of Chloroxylenol on Eudrilus eugeniae Survival after 14 and 21 Days ...... 47 Figure 4-4: Effect of Sodium Hypochlorite on Eudrilus eugeniae Survival after 7 Days ...... 48 Figure 4-5:Effect of Sodium Hypochlorite on Eudrilus eugeniae Survival after 14 and 21 Days ...... 48 Figure 4-6: Effect of Lactic acid on Eudrilus eugeniae survival after 7 Days ...... 49 Figure 4-7: Effect of Lactic acid on Eudrilus eugeniae Survival after 14 and 21 Days ...... 49 Figure 4-8: Effect of Chloroxylenol on Body Weight Change of Eudrilus eugeniae ...... 50 Figure 4-9: Effect of SodiumHypochlorite on Body Weight Change of Eudrilus eugeniae ...... 51 Figure 4-10: Effect of Lactic acid on BodyWeight Change of Eudrilus eugenienaie ...... 52 Figure 4-11: Nutrient contents of Biosolids Produced by Earthworms Exposed to Chloroxylenol ...... 53 Figure 4-12: Nutrient contents of Biosolids Produced by Earthworms Exposed to Sodium Hypochlorite 54 Figure 4-13: Nutrient contents of Biosolids Produced by Earthworms Exposed to Lactic acid ...... 55 Figure 4-14: Effect of Chloroxylenol on Earthworms E. coli Removal ...... 55 Figure 4-15: Effect of Sodium Hypochlorite on Earthworms E. coli Removal ...... 56 Figure 4-16: Effect of Lactic acid on Earthworms E. coli Removal ...... 56 Figure 4-17: Effect of Chloroxylenol on Earthworm Total coliforms Removal ...... 57 Figure 4-18: Effect of Sodium Hypochlorite on Earthworms Total coliforms Removal ...... 57 Figure 4-19: Effect of Lactic acid on Earthworms Total coliforms Removal ...... 58 Figure 4-20: Effect of Chloroxylenol on Earthworms Helminth ova Removal ...... 58 Figure 4-21: Effect of Sodium Hypochlorite on Earthworms Helminth ova Removal ...... 59 Figure 4-22: Effect of Lactic acid on Earthworms Helminth ova Removal ...... 59 Figure 4-23: Effect of Chloroxylenol on Earthworms COD Removal ...... 61 Figure 4-24: Effect of Sodium Hypochlorite on Earthworms COD Removal ...... 61 Figure 4-25: Effect of Lactic acid on Earthworms COD Removal ...... 62 Figure 4-26: Effect of Chloroxylenol on Earthworms BOD Removal ...... 63 Figure 4-27: Effect of Sodium Hypochlorite on Earthworms BOD Removal ...... 64 Figure 4-28: Effect of Lactic acid on Earthworms BOD Removal ...... 65 Figure 4-29: Effect of Chloroxylenol on Earthworm TDS Removal ...... 66 Figure 4-30: Effect of Sodium Hypochlorite on Earthworms TDS Removal ...... 66 Figure 4-31: Effect of Lactic acid on Earthworms TDS Removal ...... 67 Figure 4-32: Effect of Chloroxylenol on Earthworms TSS Removal ...... 68 Figure 4-33: Effect of Sodium Hypochlorite on Earthworms TSS Removal ...... 69 Figure 4-34: Effect of Lactic acid on Earthworms TSS Removal ...... 69 Figure B-1 Some Pictures during Laboratory Experimentation...... 100
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List of Abbreviations
BTT------Biofil Toilet Technology
BOD------Biochemical Oxygen Demand
CAS------Chemical Abstract Service
COD------Chemical Oxygen Demand
EHCC------Eco-Healthy Child Care
FSM------Faecal Sludge Management
HTH------High Test Hypochlorite
JMP------WHO/UNICEF Joint Monitoring Program
KVIP------Kumasi Ventilated Improved Pit
OECD------Organization for Economic Co-operation and Development
OSHC------Occupational Safety and Health Council
OSSs------On-Site Sanitation System
TDS------Total Dissolved Solids
TSCA------Toxic Substance Control Act
TSS------Total Suspended Solids
VIP------Ventilated Improved Pit
WASH------Water Sanitation and Hygiene
WHO------World Health Organization
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Definition of Terms
° Bactericidal chemicals: Chemicals those are able to kill bacteria. They can be
antiseptics, disinfectants or antibiotics.
° Biodegradable: A substance that can be broken down into basic molecules (e.g. carbon
dioxide, water) by organic processes carried out by bacteria, fungi, and other
microorganisms.
° Biofilcom: Biological Filters and Composters Company
° Biological treatment : The use of living organisms (e.g. bacteria) to treat waste; this is in
contrast to chemical treatment which relies on chemicals to transform or remove
contaminants from waste.
° Biosolids: Faecal sludge that has been digested /stabilized. It is a term also given to the
residue when sludge that is dewatered and dried.
° Blackwater: A mixture of urine, faeces and flushwater along with anal cleansing water (if
anal cleansing is practiced) and/or dry cleansing material (e.g. toilet paper).
° Ecotoxicology: The study of the effects of toxic chemicals on biological organisms at the
population, community and ecosystem level.
° Excreta : Consists of urine and faeces that is not mixed with any flushing water
° Faeces : Refers to (semi-solid) excrement without urine or water. Each person produces
approximately 50 litres per year of faecal matter (Buckley 2011).
° Faecal sludge: Sludge of variable consistency collected from on-site sanitation systems,
such as latrines, non-sewered public toilets, septic tanks and aqua privies. The faecal
sludge comprises varying concentrations of settle able or settled solids as well as of other,
non-faecal matter (Heinss and Strauss 1999).
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° Flush water : Is the water that is used to transport excreta from the User Interface to the
next technology. Freshwater, rainwater, recycled greywater, or any combination of the
three can be used as a flush water source,
° Helminth : A parasitic worm, i.e. one that lives in or on its host, causing it damage.
Examples include especially parasitic worms of the human digestive system, such as
roundworm (e.g. Ascaris) or hookworm.
° Improved Sanitation facilities: Facilities that hygienically separates human excreta from
human contact. Improved sanitation facilities include flush/pour flush (to piped sewer
system, septic tank, and pit latrine), Ventilated Improved Pit (VIP) latrine, pit latrine with
slab and composting toilet.
° Lethal concentration: The concentration of the toxicant which is able to kill all the test
organisms within the specified exposure time.
° On-Site Sanitation: System of sanitation where the means of storage are contained
within the plot occupied by the dwelling and its immediate surroundings. It may be
disposed of on site or removed manually for safe disposal (WHO 2006).
° Pathogen : Infectious biological agent (bacteria, protozoa, fungi, parasites, viruses) that
inflicts disease or illness on its host.
° Sewage : General name given to the mixture of water and excreta (urine and faeces),
although in the Compendium it referred to as blackwater.
° Slum: A heavily populated usually urban area characterized by crowding, informal
settlements, dirty run-down housing, unsanitary condition and social disorganization.
° Shared sanitation facilities : These are sanitation facilities of an otherwise acceptable
type that are shared between two or more households, including public toilets.
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° Stabilized : The term used to describe the state of organic material that has been
completely oxidized and sterilized.
° Toxicity : Is the degree to which a substance can damage an organism such as an animal,
bacterium or plant as well as the effect on a substructure of the organism.
° Vermi-biofilter : The utilisation of earthworms in waste water or sludge treatment system.
° Vermicast: The end-product of the breakdown of organic matter by different earthworm
species. It is also called worm castings or worm manure.
° Vermicomposting: Involves the bio-oxidation and stabilization of organic matter by the
joint action of earthworms and microorganisms.
° Vermiculture: The cultivation of earthworms in an organic waste management system.
° Waste digesters : These are invertebrates (e.g. earthworms and Black Soldier Fly) that
feed voraciously on organic waste including faecal matter.
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CHAPTER ONE 1.0. INTRODUCTION
1.1. Background
One of the major environmental development challenges that majority of developing countries face is the provision of safe sanitation services in both urban and rural areas (Mulenga
2011; Prasad, 2013). While efforts have been made by some governments to provide basic level of these services to the population, the coverage levels have remained insufficient and only 64 percent of the global population uses improved sanitation facilities and 15 percent defecate in the open (WHO/UNICEF, 2013).
The rapid population growth magnifies the scarcity of safe sanitation facilities as a result of limited space for construction and the overuse of the already inadequate existing sanitation facilities. These lead to large faecal production in these spaces without adequate treatment and reduction, resulting in the need for frequent desludging of such sanitation facilities and indiscriminate disposal into open spaces and water bodies without proper treatment (Niwagaba
,2009).
The sanitation needs of 2.7 billion people worldwide are served by onsite sanitation (OSS) technologies (Boston Consulting Group, 2013). According to the findings of Strauss et al.,
(2000), in most sub Saharan Africa countries, more than 75% of houses in large cities and 100% in towns are connected to On- Site Sanitation systems(OSSs).They also found out that, about
85% of the inhabitants in Ghana are relying on OSSs (Strauss et al., 2003). However, despite the fact that sanitation needs are met through onsite technologies for a vast number of people in urban areas of low- and middle-income countries, there is typically no management system in
1 place for the resulting accumulation of FS and most of it is usually discharged untreated into the environment, posing great hazards to water resources and to public health (Strande et al., (2014).
Based on such problems, the Biofil Toilet Technology (BTT) as shown in Figure 2.1 was developed to resolve the peculiar sanitation issues of limited availability of space for sanitation facilities and odour generation with simple treatment mechanisms. This is to ensure effective on- site faecal sludge treatment and also to eliminate frequent desludging of OSSs as observed in the traditional systems such as the KVIPs, Aqua privy and septic tanks. The BTT works based on vermicomposting under aerobic conditions with solid-liquid separation and bio-filtration as the main treatment processes. Black water enters at the top of the digester where rapid separation of the solids and liquid contents occur through a pervious concrete filter. Earthworms, bacteria or other micro-organisms degrade organic solid residue (cleansing paper, faeces and all degradable material) while the effluent is biologically filtered out of the bottom of the digester through a sand media and drained into the sub-surface soil where further polishing occurs.
The population of micro-organisms present inside most OSSs determines the effective functioning of the system (Ip, 2004). However, the activities of such organisms are greatly influenced by the introduction of bactericidal chemical constituents with black water during cleaning of the toilet bowls.
Bactericidal chemicals which are commonly used for cleaning are laundry detergents, liquid chlorine bleaches, high test hypochlorite (HTH) and some other toxic chemicals that can be added to many of the household toilets during flushing(Gross, 1978). According to the study of Trevors et al (1993), the excessive use of household detergents and chemicals in toilets can seriously hinder microbial activities inside many OSSs. Given that the Biofil toilet technology is highly dependent on the activities of macro/micro-organisms, the introduction of bactericidal
2 chemicals may impact toxicological effects on such organisms inside the vermibed limiting the full working capacity of the technology.
1.2. Problem Statement
Faecal sludge management is becoming problematic in the urban poor populated areas due to high generation rate of excreta without effective technologies for treatment (Lue-Hing et al.,
1996) . Most times, faecal sludge is dumped to the nearest possible area however, about 80% of the faecal sludge is composed of organic material which can be recycled and removed by adequate and proper OSSs (Ali, 2002). This indicates that there is a need for an accelerated decomposition of faecal organic material and safe disposal to maintain public health and to protect the environment.
Bactericidal chemical pollutants may cause long term effect on the biological processes of
OSSs. The frequent additions of these chemicals also lead to serious environmental problems. In most developing countries, regulations on the use and disposal of bactericidal chemicals have become more stringent however; many households who use onsite sanitation system are not informed about the proper use of cleaning chemicals and general maintenance of the sanitation system (Duncan, 1992).
Even though the BTT is trying to resolve this menace by accelerated excreta volume reduction, its effectiveness may also be compromised by the addition of cleaning bactericidal chemicals. This could be fatally toxic to the macro and microbes above certain critical dosages
(Gross, 1978).
This implies that determining the fatal concentration of cleaning bactericidal chemicals is crucial for the effective functioning of the organisms present in the OSSs. Therefore there is a need to test the level of tolerance, optimum performance and constraints of macro/micro-organisms with
3 respect to bactericidal chemicals during flushing of toilet to provide criteria for the design and optimization of the biofil toilet technology.
1.3. Research Questions
The study was carried out to answer the following questions:
∑ Are earthworms resistant to strong antiseptics and other toxicants like, chloroxylenol
(dettol solution), sodium hypochlorite (parazone solution) or lactic acid (Mr. Muscle
solution)?
∑ What level of contaminant concentration (i.e. Lethal concentrations) will render the
system ineffective for decomposition/ breakdown of organic constituents in black water?
∑ What is the recovery rate of the system after bactericidal chemical contamination to the
decomposition or breakdown of organic constituents in black water?
1.4. Research Aim and Objectives
The main focus of the research is to assess the robustness of the Biofil Toilet Technology to bactericidal chemical constituents in blackwater.
The specific objectives of the research are:
1. To determine the survival rate of the waste digester (i.e. earthworm) in the Biofil toilet
technology when exposed to bactericidal chemicals in flush water.
2. To determine the lethal concentration of bactericidal chemical constituents that will
render the biofil toilet technology ineffective for organic contaminant removal in black
water.
3. To determine the recovery rates of the earthworms after the application of bactericidal
chemical constituents in flush water.
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1.5. Justification
As only little research has been conducted yet about the operational and maintenance parameters of the BTT, the outcome of this study will provide data to inform the optimization of the BTT with respect to the performance of earthworms towards the different cleaning chemicals; the quality of the biosolids produced by earthworms for agricultural application.
Moreover, undertaking this study will provide useful information about the type of cleaning bactericidal chemicals that can be used and their adverse effect on the BTT to expand the applicability of the technology in various communities of the urban poor.
Generally, the outcome of this study will help the technology developer;
1) To reduce the cost of operation and maintenance once the information on the type and
effect of cleansing bactericidal chemicals and working performance of earthworms is
known.
2) To increase soil fertility through production of biosolids which is nutrient rich manure;
once the earthworms are not affected by the toxic bactericidal chemicals which enter into
the system with blackwater, the biosolid production rate and quality may also increase.
1.6. Scope of the Study
This study covered the adverse effects of the bactericidal chemicals; chloroxylenol (Dettol solution), sodium hypochlorite (parazone solution) and lactic acid (Mr. Muscle) on earthworms.
The study involved laboratory scale experiments only. No field trials were conducted.
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1.7 Organization of the Thesis
Details of the work done during this study are presented as follows:
Chapter 1 presents an introduction to the subject of the research, the problem statement, research objectives, significance and scope of the study whilst Chapter 2 reviews the pertinent literature.
Chapter 3 presents the general methods applied in the research including the experimental procedures used to achieve the goal of the study. Chapter 4 presents the results and discussions of the research focusing on the findings of the experiment. Finally, the conclusions and recommendations of the study are given in Chapter 5.
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CHAPTER TWO 2.0. LITERATURE REVIEW
2.1. Introduction
Sanitation is a basic human requirement, its main purpose being the separation of human waste from human settlements in order to prevent diseases (Flores et al., 2008). The introduction of basic sanitation system can provide a range of health advantages besides other positive benefits to many households and communities at large (Heather et al., 2013). Therefore, a given sanitation technology should be able to provide user privacy, minimize human and insect contact with excreta, and prevent damage to water resources and the environment.
In urban areas of most developing countries, on-site disposal and dealing with treatment of the excreta where it is deposited, can provide hygienic and satisfactory solution for such communities (Franceys et al., 1992). On-Site Sanitation systems (OSSs) predominate over water- borne, sewered sanitation system (Strauss et al., 2003). Sewerage systems are too costly to be provided to all, and only wealthier, upper and middle class areas normally benefit (Franceys et al.,1992). The cost of a sewerage system (which is usually more than four times that of on-site alternatives) and its requirement of a piped water supply preclude its adoption in many communities in developing countries that lack adequate sanitation. In most of the developing countries, pit toilets and the flush toilets are the most commonly used sanitation technologies for faecal sludge management (Seleman, 2012).
Pit latrines are the most rudimentary form of sanitation (Franceys et al.,1992). Excreta that are deposited into a pit latrine are subject to biodegradation, which substantially reduces the volume (Brouckaert et al., 2012). The simplicity and low cost of pit latrine construction, operation and maintenance contribute to its widespread use. Unfortunately, pit latrines can
7 contaminate groundwater supplies Jacks et al., (1999), often gives bad odour and serve as a breeding ground for disease vectors. They are also impractical in rocky and sandy places, areas with high groundwater table, and in settlements having insufficient space for burying pit contents or building replacement pit latrines (Flores et al., 2009). Ventilated Improved Pit (VIP) latrines are improved latrines over traditional latrines in two important respects: they mitigate the noxious odour and reduce the number of flies and other insects that plague users of traditional latrine. The provision of a vent pipe on the pit allows fresh air to flow through the latrine, reducing odour. The vent also allows light into the latrine, attracting insects into the pipe, where they are trapped by the fly screen at the top of the pipe (Heron, 2005).
Pour flush latrines use pit for excreta disposal and have a special pan which is cast on the floor slab and provides a water seal of 20-30 millimetres. This ensures that smell cannot escape into the shelter (Buckley, 2011). Pour flush latrines require between one to three litres of water for flushing each time they are used, although ideally more should be used. Once excreta have been flushed into the pit, the liquids will filter into the ground. Some of the solids will be decomposed by micro-organisms and filter into the ground; others remain in the pit (Brouckaert et al., 2012). In pour flush latrines there is no fly or smell problems, making it hygienic and pleasant to use and maintenance is relatively straight forward. If they are not used properly, however, there is a risk of disease transmission (WHO, 2004).
In addition many OSSs facilities installed in most urban and peri-urban areas are operating with technical and cultural problems in which most women and disabilities would find difficult to access it properly (Gunawardana et al., 2011). Generally, more than 90% of the sewage is discharged without appropriate treatment increasing the risk of health problems and also a total
8 of 2.6 billion people lack access to basic sanitation in developing countries (WHO/UNICEF
,2010).
In Ghana, urban sanitation infrastructure is poor and only a small portion of wastewater
(primarily domestic) is collected for treatment and disposal (Kwashie, 2009). Majority of people especially in the urban areas still rely on shared or public sanitation facilities. Only 14 percent of
Ghana’s population have access to improved sanitation facilities with 58 percent resorting to shared or public facilities. About 9 percent use unimproved facilities and the remaining 19 percent do open defecation (WHO/UNICEF, 2012). The most common system used for treating faecal sludge in Ghana is the waste stabilisation ponds (Awuah et al., 2001).
In Kumasi, about 500m 3 of faecal sludge is generated daily Keraita, et al., (2002) and treated by pond systems. The Kumasi Metropolitan Assembly (KMA) moved from direct provision of sanitation services to promoting and establishing active involvement of both communities and the private sector in faecal sludge management (Strauss et al., 2003).
2.2. Faecal Matter Characteristics and Composition
Faecal matter is a rich source of inorganic plant nutrients such as nitrogen, phosphorus, potassium, and organic matter. Each day, humans excrete in the order of 30g of carbon (90g of organic matter), 10-12g of nitrogen, 2 g of phosphorus and 3g of potassium. Most of the organic matter is contained in the faeces, whilst most of the nitrogen (70-80%) and potassium are contained in urine. Phosphorus is equally distributed between urine and faces (Trondel, 2010;
Drangert, 1998). In reality, part of this potential is lost though, during storage and treatment (e.g. nitrogen loss through ammonia volatilization) (Wood, 2013).
9
Faeces can contain large concentrations of pathogenic viruses, bacteria, cysts of protozoa and eggs of helminthes (Petterson and Ashbolt, 2006). Normally 30% of the dry mass of faeces is made up of bacteria and 80% can be considered biodegradable. 70-80% of wet sludge is made up of water which highly depends on dietary intake and digestive function of each human (
Torondel, 2010; Buckley, 2011).
A study conducted in Accra, Ghana, evaluating only septic tank FS, observed Total
Solids (TS) concentration of 11900 (mg/l). Another study conducted in Ouagadougou, Burkina
Faso, in a septic tank system showed an average TS concentration of 19000 mg/l and COD of
13500 mg/l (Strauss, 2000). Results from Dakar, Senegal were also highly variable with TS 4500
- 14000 mg/l, and COD 7100 - 15700 mg/l (Ingallinella et al., 2002).
2.2.1. Daily Excretion of Urine and Faeces
The amount of faeces produced by a person depends on the composition of the food consumed. Foods low in fibres, such as meat, result in smaller amounts (mass and volume) of faeces than foods high in fibre ( Guyton, 2003). The faecal production in the developed countries is approximately 80-140g/p,d (wet weight) of faeces, corresponding to about 25-40g/p,d of dry matter ( Kärrman, 2005; Tidåker et al., 2007). Faecal excretion rate in the developing countries is on average 350g/p, d in rural areas and 250g/p, d in urban areas (Feachem et al., 1983). In China,
Gao et al., (2002) measured 315g/p, d while Pieper (1987) measured 520g/p, d in Kenya.
Schouw et al., (2002) measured faecal generation of 15 individuals in three different areas in
Southern Thailand and obtained wet faecal generation rates of 120-400g/p,d. Faecal excretion rate is on average one stool per person per day, but it may vary from one stool per week up to five stools per day per person (Niwagaba, 2009).
10
The quantity of urine excreted depends on how much a person drinks and sweats, and also on other factors such as diet, physical activity and climate (Vinnerås, 2001). Excessive sweating results in concentrated urine, while consumption of large amounts of liquid dilutes the urine. The urine generation rate for most adults is between 1000 and 1300g/p, d (Feachem et al.,
1983). Vinnerås, (2001) suggested a design value for urine generation to be 1500g/p, d based on measurements in Sweden, while Schouw et al., (2002) found that in Southern Thailand between
600-1200 g/p d of urine were produced. Based on measurements in Switzerland, Rossi et al.,
(2009) reported urine generation rate of 637 g/p,d on working days and 922g/p,d on weekends, which is in agreement with 610-1090g/p,d reported by Jönsson et al., (1999) based on measurements in Sweden. The average production of faeces and urine per head varies according to food type and other environmental conditions (Table 2-1).
Table 2-1: Excreta and urine Generation Rate per Person in Different Regions
Region Faeces (g/cap/d) Urine(g/cap/d) Africa 400 1200 USA 86 1050 China 69 845 Europe, North America 100-200(wet faecal weight) Developing countries 130-520(wet faecal weight) Vietnam 1370 (faeces+ urine) Thailand 1000 (faeces+ urine) Adapted from (Heniss et al., 1997)
2.3. Faecal Matter Treatment Problems
In urban and peri urban areas of many developing countries, faecal matter disposal situation is problematic. Thousands of tonnes of faecal matter is collected from many on-site
11 sanitation installations and disposed of untreated (Bassan et al., 2013). The inadequate and unsanitary disposal of faecal matter leads to the contamination of ground water and other sources of water. In faecal sludge treatment of most traditional OSSs, pathogens remain without any destruction. For instance in dry toilets where ash is used to elevate pH to >9, E. coli counts are reduced in one year; however helminth ova or Clostridium, hookworms, tapeworms, or roundworms often occur in very high counts (Sherpa et al., 2009). The problem is multiplied when fresh faecal matter is left without proper treatment due to its difficulty in handling and the existence of high concentrations of pathogens (Feachem et al., 1983; WHO, 2006). Therefore, reduction of pathogens, particularly human intestinal nematodes and faecal bacteria, are the most important micro-organisms to consider during treatment of faecal matter (Heron, 2005).
Thus, as the challenges of faecal matter treatment increase, new innovations are coming into existence to improve sludge degradation and management. Hence, effective excreta management at the household and community levels produces far ranging societal benefits by reducing the risks of disease causing pathogens.
2.4. Back Ground of the Development of Biofil Toilet Technology
Around the world, people both in rural and urban areas have been using human excreta for centuries to fertilize fields and fishponds and to maintain or replenish the soil organic fraction, i.e. the humus layer (Cross, 1985). Up to date, using human excreta as an agricultural input is common in China and Southeast Asia as well as in various places in Africa (Strauss et al., 2000).
Excess sludge treatment and disposal symbolizes a rising challenge for wastewater treatment plants due to economic, environmental and regulation factors (Wei et al., 2003). There is therefore considerable interest in developing technologies for reducing sludge production in biological wastewater treatment processes. To solve such issues researches were undertaken to
12 look for cost effective, environmentally friendly and sustainable technologies for wastewater treatment in most urban cities. Different biological treatment options which involve the work of both macro and micro-organisms were the most important areas of concern (Ghatnekar., 2010).
Vermiculture biotechnology and microbial wastewater treatments are gaining wide acceptance and it is the promising treatment technology with almost no- environmental discharge (Lakshmi,
2012).
Earthworms are known to be the master bio-processing agents for the management of organic effluents from diverse sources ranging from domestic sewage to industrial effluents
(Ghatnekar et al., 2008). Vermicomposting of organic waste as a predominant system for decentralized waste water treatment method was introduced to reduce cost of treatment, environmental health risks, and to recover basic nutrients from the wastewater (Gnanaprakasam et al., 2013). The performance of earthworms for sludge reduction in biological wastewater treatment has been paid more attentions than that of protozoa and bacteria for sludge volume reduction (Xing et al., 2011).
Biofil toilet technology (BTT) is one of the youngest biotechnologies invented with the idea of the vermicomposting process to solve the problems of organic waste accumulation in residential areas of developing countries. It is applied with the principle of vermi-biofiltration process
(conventional filtration processes with the vermicomposting techniques).
It is an initiative of a local entrepreneur (K. Anno Engineering Ltd) in Accra. The Civil and Mechanical/Agriculture/Marine Technical Divisions of the Ghana Institute of Engineers of
Ghana in collaboration with K. A. Anno Engineering Limited on Tuesday June 24, 2008 organized the launching of the Biofil Toilet System at the Engineers Centre in Accra. The system has for the last 4-5 years been installed for individual home owners in the low, middle and high
13 income areas, some institutions, refugee camps, resettlement communities and mining communities.
Since its development and installation, there has not been any detailed research conducted on it, though a sample of the effluent from the system was once tested by the Centre for
Scientific and Industrial Research in Accra on June 2010. Their test involved the effluent quality analysis of an individual Biofil toilet technology which was compared with some parameters
(pH, Conductivity, BOD, COD, Temperature, PO 4-P, NO 3-N, NH 4-N and NO 2) of the EPA guideline for wastewater discharges. However, no specific tests have been run on the system components such as the filtering membrane, bulking materials and the waste digesters
(Biofilcom, 2012).
2.4.1. Current Biofil Toilet Technology Application for Blackwater Treatment
The Biofil toilet technology (Figure 2-1) is a simple compact on-site blackwater treatment system that uniquely combines the benefits of the flush toilet system and those of the dry toilets.
Earthworms are used to seed the system once after initial use of the system to initiate the accelerated decomposition process. Blackwater dewatering and accelerated waste stabilisation are the main features of this technology, leading to a bio-solid product which may be recycled as an organic fertiliser or soil conditioner (Biofilcom, 2012).
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A C D B
Figure 2-1: The Biofil Toilet Technology
(A) = standalone micro-flush Biofil toilet technology; (B) = standalone micro-flush seat connected to hand washing facility; (C) = Biofil toilet technology retrofitted to a WC installed on subsurface soil; and (D) = flush retrofit Biofil toilet technology installed in the ground) The digester (i.e. concrete box panel) in Figure 2-2 is 0.61m high, 0.61m wide and 1.83m long. It can be installed buried in the ground or on the subsurface soil depending on the level of the water table or presence of rock beds which may prevent excavation. It can be connected to a water closet as a retrofit to the septic tank or pour flush system (called the flush system) or installed as a stand-alone connected to a hand washing facility (called the micro-flush). In this case, wastewater from the hand washing facility serves as a water seal and also flush water for the next user. The micro-flush is ideally designed for areas with unreliable water supply.
15
A B
Figure 2-2: The Biofil Toilet Separate Digester (A), the Internal View of the Digester (B) Within the concrete box panel in Figure 2-3 is a pervious filter membrane made of grade of gravel and supported on pavement blocks from the bottom platform. On top of the filter membrane are bulking materials made of shredded coconut fibre and grass. A fine mesh is used to line the filter membrane to prevent fines from the bulking materials clogging it.
The bottom of the concrete box panel has two designs; that is a flush or micro-flush Biofil toilet technology. In the case of the flush system, the bottom is sealed with a concrete panel and sloped at an angle to channel the effluent through a drain field for further polishing by sub- surface infiltration. In the case of the micro-flush, the bottom of the box has no concrete panel. In both cases, a filtering media of sand or coarse gravel is placed beneath the filtering membrane for further polishing of the effluent before entering the sub-surface soil. Between the top cover and bulking material and the filter membrane and the bottom concrete box panel are air spaces.
A vent is provided on top cover for aeration.
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Figure 2-3: Schematic Design of the Biofil Toilet Technology The design of the digester is simple, replicable and operates on very low maintenance needs. The system eliminates the possibility of costly site remediation and clean-up (as in the case of failed septic / KVIPs).
2.5. Vermicomposting Technology
Vermicomposting is emerging as the most appropriate alternative to conventional aerobic composting. This process is not only rapid, easily controllable, cost effective, energy saving, and a zero waste process, but also accomplishes most efficient recycling of organics and nutrients
(Eastman et al., 2001). Vermicomposting is a viable low-cost technology system for the processing and treatment of organic solid wastes (Hand et al., 1988). The potential of earthworms in soil processing due to their burrowing nature and composting of organic matter has been realized and simple appropriate vermiculture biotechnology has been developed which may solve the problems of waste processing and management to a large extent (Basheer and
Agrawal, 2013).
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It has been demonstrated that earthworms can process household garbage, city refuse, sewage sludge and waste from paper, wood and food industries (Ismail, 2005). The use of earthworms in composting process decreases the time of stabilization of the waste and it also produces an efficient bio-product, i.e., vermicompost. Most researchers agree that microorganisms are largely responsible for organic-matter decomposition (Ansari and Ismail,
2012; Grdiša and Grši, 2013). Earthworms play a role in the rates of decomposition directly, by feeding on and fragmenting the organic matter. This also affects the rates of decomposition indirectly through interactions with microorganisms, basically involving stimulation or depres- sion of microbial biomass activity and enzymatic activity (Dominguez and Aira, 2011).
2.6. Earthworms and Their Effect for Soil Conditioning
2.6.1. Introduction
Earthworms are segmented invertebrates belonging to the phylum annelid and the class oligochaeta (Gajalakshmi and Abbasi, 2004). The body segmentation is purely an external feature but exists internally too. Earthworms are so called because they are almost always terrestrial and burrow into moist-rich soil, emerging at night to forage. They are long thread like elongated, cylindrical soft bodied animals that are hermaphrodites and usually reproduce by mating, each partner fertilizing the other. After mating they retract their bodies through the
“saddle” or clitellum and pass it over their heads. Each cocoon contains one or more eggs that can survive adverse conditions, hatching when environmental conditions are favourable (Ansari and Ismail, 1985). In order to protect themselves from enemies and desiccation, most of the species prefer to live in burrows and come out during night in search of food (night crawlers)
(Basheer and Agrawal, 2013).
18
The medical value of earthworms has been known for centuries. The extracts prepared from earthworm tissues have been used for the treatment of numerous diseases since they are valuable source of proteins, peptides, enzymes and physiologically active substances (Grdiša and
Grši, 2013)
2.6.2. Effects of Earthworms for Soil Conditioning
Earthworms promise to provide cheaper solutions to several social, economic and environmental problems plaguing the human society. They are both protective and productive for the environment and society (Kumar and shweta, 2011). Their bodies work as ‘a bio-filter’ and they can ‘purify’ and also ‘disinfect’ and ‘detoxify’ soil wastes (Dominguez and Edwards, 2011).
The importance of earthworms in the breakdown of organic matter and the release of the nutrients that it contains has been known for a long time (Mallappa et al., 2010). Their activities are beneficial because they can enhance soil nutrient cycling through the rapid incorporation of detritus into mineral soil. Earthworms bring about physical, chemical and biological changes in the soil through their activities and thus are recognized as soil managers (Ismail, 2005). They can stabilize biodegradable organic matter, such as animal waste, vegetable and municipal sludge like the conventional composting. The end product of such composting gives a finely divided peat-like material with high porosity and water holding capacity that contains most nutrients in forms that are readily taken up by the plants (Dominguez, 2004) . The earthworm casts are rich in organic matter and have high rates of mineralization that implicates a greatly enhanced plant availability of nutrients, particularly ammonium and nitrates.
A study by Landrum et al., (2006) also shows that earthworms are essential invertebrates in the later stages of soil formation, in maintaining soil structure and fertility and can be utilized as a tool to assess different transformations and impacts. Mucus production associated with water
19 excretion in earthworm guts also enhances the activity of other beneficial soil microorganisms
(Grdiša and Grši, 2013).
2.7. Environmental Conditions for Survival and Growth of Earthworms
Cocoon production, rates of development, and growth of earthworms are all critically affected by environmental conditions. Epigeic earthworms are relatively tolerant to the environmental conditions of organic wastes, so quite simple low management or bed systems have been used extensively to process these wastes (Dominguez and Edwards, 2011). Norbu,
(2002) from Thailand also reported that environmental conditions like temperature, pH, moisture content and aeration are vital for breeding, cocoon production and hatching of young earthworms. There is a lot of literature describing the various limiting parameters towards a successful breeding (Ansari and Ismail, 2012;Ronal et al.,1997 and Norbu, 2002).
2.7.1. Temperature
Earthworms tolerate cold and moist conditions far better than hot and dry conditions.
Whilst tolerances and preferences vary from species to species, temperature requirements are generally quite similar (Norbu, 2002). The majority of vermicomposting worms can tolerate temperatures ranging from 10 to 35 but decrease in activity may occur as temperatures move toward the extremes of this range (Riggle et al., 1994; Sherman, 2003).
2.7.2. Hydrogen Ion Level (pH)
Although studies have suggested that worms perform best in neutral pH Ronald et al.,
(1977); Gajalakshmi and Abbasi, (2004), it has been recorded by Dominguez and Edwards,
(2011) that different species of earthworms have their own pH sensitivity and generally most of them can survive at the pH range between 4.5 – 9. The value of pH in vermicomposting media is
20 varying due to the fragmentation of the organic matter under series of chemical reaction by micro-organisms (Norbu, 2002).
2.7.3. Moisture Content
Most researchers agree that the moisture content of the soil is the basic parameter for earthworm activities as earthworm species have different moisture requirements in different regions of the world. Avoidance of water loss is a major factor in earthworm survival as water constitutes 75-90% of the body weight of earthworms (Ansari and Ismail, 1985). However, they have considerable ability to survive adverse moisture conditions, either by moving to a region with more moisture (Mattson et al., 2005) or by means of aestivation (Baker, 2002). Soil moisture also influences the number and biomass of earthworms (Wood, 1974). They need generally moisture at the range from (60 –75) %. The soil should not be too wet or else it may create an anaerobic condition which may drive the earthworms from the vermibed (Ronald et al.,
1977). Soil moisture also influences the number and biomass of earthworms (Manaf et al.,
2009).
2.7.4. Aeration
Earthworms lack particular respiratory organs. Oxygen and carbon dioxide diffuse through their body wall. Thus, earthworms are very sensitive to anaerobic conditions (Ronald et al.,
1997). Eisenia fetida, a type of worm for example, have been reported to migrate in high numbers from a water-saturated substrate in which oxygen has been depleted, or in which carbon dioxide or hydrogen sulphide has accumulated (Dominguez and Edwards, 2011).
21
2.8. Breeding, Biology and Classification of Earthworms
Worms can be easily bred in the laboratory for toxicity testing and their prolonged existence makes it unlikely that numerous worms would die during the period of toxicity test in untreated media (OECD, 1984). Earthworms can be bred by setting up a vermibed in a suitable container or a site under a shade, in an area on upland or an elevated level to prevent water stagnation in the pit (Spurgeon, 1995).
2.8.1 Life Cycle of Earthworms
Population dynamics, productivity and energy flow in earthworms cannot be fully understood unless the life cycle of the earthworm is known. Studies on the lifecycles of earthworms are also necessary for effective vermiculture (Bhattacharjee and Chaudhuri, 2002).
Figure 2-4: Schematic Diagram of the Life Cycle of Earthworm
Source: Ronald et al., (1977)
2.8.1.1. Cocoon Phase
At first, cocoons are quite soft. It can be deposited in the soil and becomes slightly amber, leather-like, and very resistant to drying and damage. Cocoons are very tiny, and look like the shape of a lemon. They can survive underground until conditions are right for hatching (Journey,
22
2014). Earthworms particularly eudrilus eugeniae species prefer controlled temperature (25 ) to hatch the cocoons far better than the fluctuating temperature (25 – 37) (Seaman, 1992).
Earthworms take 10-55 weeks to get matured and be able to produce cocoons (Journey, 2014).
2.8.1.2. Juvenile Phase
Young worms hatch from their cocoons in three weeks to five months. The gestation period varies for different species of worms. It also depends on conditions like temperature and soil moisture. Hatching is delayed if conditions are poor (Norbu, 2002). On hatching, the earthworms measure to an average up to 0.8 – 1.5 mm in length and weigh about 7 mg. Their length gradually increases up to 4 cm and may latter weigh about 150 mg (Ismail, 1997).
2.8.1.3. Non-Clitellates Phase
Young earthworms whose clitellum is yet to develop are grouped into the non-Clitellates.
The young worms are very active at this stage and may have a body weight ranging from 150 mg to 450 mg (Edward et al., 1976; Ismail, 1997).
2.8.1.4. Clitellates Phase
Clitellates are the mature and adult earthworms. Clitellates have the potential for reproduction. The earthworms at this stage appear bit darker in color due to the pigmentation of the epithelial cells (Ismail, 1997). Here in this stage of life cycle, the body wall of the forward cell is thickened by gland cells, forming a conspicuous girdle known as Clitellum (Ronald et al.,
1977).
At the time when many earthworms are young with favorable climatic condition, they become very active. This high level of physical activeness normally continues throughout the year except during hot summer where they become inactive (Ronald et al., 1977). Seaman,
23
(1992) reported that the constant temperature and controlled temperature favours the development of clitella and cocoon production . A maximum of 52 days are required for the development of Clitellum for most epigeic species (Joshi et al., 2008).
2.8.2. Biology of Earthworms
The physical structure of earthworms is similar among the different species of earthworms.
Their bodies are streamlined, containing no protruding appendages or sense organs which enable them to pass easily through soil. Worms have well-developed nervous, circulatory, digestive, excretory, muscular, and reproductive systems (Sherman, 2003).
Setae (bristles) on each segment of their body can be extended or retracted to help earthworms move. Lubricating mucous, secreted by skin glands, helps worms move through soil and stabilizes burrows and castings. Earthworms swallow soil (including decomposing organic residues in the soil). Swallowed matter is mixed by strong muscles and moved through the digestive tract while enzyme-filled fluids are secreted and blended with the materials. The digestive fluids release amino acids, sugars, bacteria, fungi, protozoa, nematodes, and other microorganisms, in addition to partially decomposed plant and animal materials from the food the worms have swallowed. Earthworms do not have specialized breathing devices. They breathe through their skin, which needs to remain moist to facilitate respiration. Earthworms can live for months completely submerged in water, and they will die if they dry out (Gajalakshmi and
Abbasi, 2004).
Earthworms are hermaphroditic, meaning each individual possesses both male and female reproductive organs. The eggs and sperm of each earthworm are located separately to prevent self-fertilization. When worms mate, they face in opposite directions and exchange sperm; the
24 eggs are fertilized at a later time (Dominguez and Edwards, 2011; Gajalakshmi and Abbasi,
2004).
2.8.3. Classification of Earthworms
Earthworms occur in the warmest soils and many tropical soils. They are divided into 23 families, more than 700 genera, and more than 7,000 species. Their size ranges from 2.5 to 183 centimetres(cm) and are found seasonally at all depths of the soil (Dominguez and Edwards,
2011). The various species of earthworms can be grouped into three categories according to their behaviour in the natural environment: anecic, endogeic, and epigeic.
Anecic species, represented by the common night crawler ( Lumbricus terrestris ), construct permanent vertical burrows as deep as 123 to183 cm in the soil. They feed on organic debris on the soil surface and convert it into humus. If anecic species are deprived of their permanent homes, they will discontinue breeding and cease to grow (Sherman, 2003; Gajalakshmi and
Abbasi, 2004).
Endogeic species, such as Aporrectodea calignosa, build wide-ranging, mainly horizontal burrows where they remain most of the time, feeding on mineral soil particles and decaying organic matter. They are the only species of earthworms that actually feed on large quantities of soil. As they move through the soil and feed, they mix and aerate the soil and incorporate minerals into the topsoil (Sherman, 2003).
Epigeic species, represented by the common red worm Eisenia fetida , do not build permanent burrows. Instead, they are usually found in areas rich in organic matter, such as the upper topsoil layer, in the forest under piles of leaves or decaying logs, or in piles of manure.
25
Since they do not burrow deeply into the soil and prefer to eat rich organic matter, epigeic worms adapt easily to vermiculture and vermicomposting systems (Sherman, 2003).
2.8.4. Earthworm Species Suitable for Sludge Stabilization
Epigeic species of earthworms, with their natural ability to colonize organic wastes, high rates of consumption, digestion, and assimilation of organic matter, tolerance to a wide range of environmental factors, short life cycles, high-reproductive rates, and endurance and tolerance of handling, show good potential for vermicomposting(Gajalakshmi and Abbasi, 2004;Dominguez and Edwards, 2011).Sivasankari et al., (2013) reported that out of all earthworm species four, namely Eisenia fetida, Lumbricus terrestris, Perionyx excavatus and Eudrilus eugeniae are cultured in all part of the world. Kale, (1998) documented that in tropical and subtropical countries like Africa, Eudrilus eugeniae and Perionyx excavatus are the best vermin composting earthworm species for organic waste management system. Gajalakshmi and Abbasi, (2004) on their study put the criteria for the species of earthworms for sludge stabilization and vermicomposting technology as;
1. Easy to culture;
2. High affinity for the substrate to be vermicomposted and
3. High rate of vermicast output per earthworm and per unit digester volume.
2.8.4.1. Eudrilus Eugeniae (Kinberg-1867)
These earthworm species are native to Africa, but it has been bred extensively in the
United States, Canada, and elsewhere for the fish bait market where it is commonly called the
“African night crawler” (Sivasankari et al., 2013). It is the best earthworm species that grows extremely rapidly, is reasonably prolific, and under optimum conditions can be considered as
26 ideal for production of animal feed protein. Gupta et al., (2010) also reported that eudrilus eugeniae are the fastest growing species which can consume 12 mg of waste per day.
A study by Sivasankari et al., (2013) recently researched on the growth and reproduction of eudrilus eugeniae by using cow dung as a feed. They measured important parameters like, cocoon production, biomass and length change by earthworms. A maximum of 280 mg of biomass per week and 18.4 cm of length within 60 days was recorded. They were also able to get cocoon production and hatchlings after 30 and 45 days respectively.
Eudrilus eugenaie (Kinberg-1867) are used in vermicomposting technology in many West
African countries including Ghana, Nigeria and Ivory Coast (Mainoo, 2007) . Their populations increases within short periods of time as they get complimentary conditions like (temperature of
25-30 , organic matter and optimum moisture content) (Seetha et al., 2012). Dominguez and
Edwards, (2011) documented that the main drawbacks of this species is its narrow temperature tolerance and sensitivity to handling. E. eugeniae has high-reproduction rates and is capable of decomposing large quantities of organic wastes quickly and incorporating them into the topsoil.
2.8.4.2. Eisenia Fetida (Savigny 1826) and Eisenia andrei (Bouché 1972)
The life cycle and population biology of E. fetida and E. andrei in different organic wastes have been investigated by several authors (Watanabe and Tsukamoto, 1976; Hartenstein et al.,
1979; Edwards, 1988; Reinecke and Viljoen, 1990). The time for hatchlings of this species to reach sexual maturity varies from 21 to 30 days (Dominguez, 2004).
2.8.4.3. Perionyx Excavatus (Perrier 1872)
Perionyx excavatus is an earthworm commonly found over a large area of tropical South
Asia (Stephenson, 1930; Gates, 1972). This tropical earthworm is extremely prolific, and it is
27 almost as easy to handle as E. fetida and very easy to harvest (Dominguez, 2004). Bioconversion of biological waste material is possible through vermitechnology employing indigenous earthworm species P. excavatus. A study by Deka et al., (2011) clearly showed that earthworm population, biomass gain and cocoon generation of P. excavatus as well as vermicompost production was quite an encouraging results therefore P. excavatus can be used for vermiculture.
2.9. Ecotoxicology of Earthworms
2.9.1. Introduction
A product’s toxicity is determined by its chemical composition – how the atoms and molecules it is made of interact with living tissues. Substances with similar chemical structures often cause similar health problems (Cox, 2008). Various sensitive endpoints have been identified in earthworm ecotoxicology, such as weight change and reproductive success
(Efrymson et al., 1997). Studies show that reproduction of earthworms has particular importance in ecotoxicological assessment because of its influence on population dynamics (Efroymson et al., 1997). Edwards, (1997) also documented that earthworms can be used to assess toxicity in terrestrial systems and the survival rate of the worms, or changes in other parameters such as biomass.
Earthworms are not only sensitive to chemicals but have a tendency to concentrate compounds such as organochlorine insecticides and heavy metals in their tissues (Friendrike et al., 2011). Some of these chemicals may have little effect on earthworms directly but may either kill predators that consume the earthworms or be taken up into predator tissues, therefore affecting animals high in the terrestrial food chain (Landrum et al., 2006).
28
Studies show that soil invertebrates like worms vary in their sensitivity to pollutants
(Owojori et al., 2009). The effect of salinity for example on an organism with a particular feeding behaviour and ecological role cannot be directly extrapolated for another organism with a different behaviour and role in the soil. Salinity of substances up to Electric Conductivity (EC) of 1.62 dSm _1 do not have any significant effect on the survival rate of earthworms (Owojori et al., 2009).
2.9.2. Toxicity Tests on Earthworms
Basic knowledge on how earthworms can resist different toxic chemicals which are found in the waste materials is vital.
To provide mechanistic understanding of contaminant uptake and loss by earthworms, a number of time-series toxicological experiments have been conducted(Spurgeon et al., 2011).
Toxicity tests carried out on various species of earthworms amongst them Eiseniaandrei and E. fetida are common species for toxicity tests.
1) Eisenia andrei
VanGestel et al., (1992) from the Netherlands have established a fairly standard procedure for testing the toxicity of chemicals to earthworms in an artificial soil mixture made up of (dry weight) 10% sphagnum peat, 20% kaolin clay, and 69% fine sand and CaCO 3 to adjust the pH to approximately 6. They tested CdCl 2, on growth and reproduction (cocoons/worm/week, the percentage of fertile cocoons, juveniles/fertile cocoon, juveniles/worm/week) of Eisenia andrei after 21 days. A concentration of 18 mg/l Cadmium (Cd) was able to reduce the number of cocoons produced/week at 23% and the number of juveniles/worm at 22% respectively.
2) E. fetida as
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VanGestel et al., (1988) evaluated the effect of soluble forms of copper on growth and reproduction of E. fetida . After 6 weeks, both growth (weight change) and cocoon production were decreased by 75% and 85% respectively at a concentration of 2000 mg/l Cu, while 1000 mg/l had no effect on the test.
Leduc et al., (2008) also tested the effects of 68 mg/l of arsenic (as potassium arsenate) on growth and reproduction of Eisenia fetida species (average initial age of 5 weeks) when added to a combination of peaty marshland soil and horse manure (1:1). The number of survivors and their live mass and the number of cocoons produced were measured. The number of cocoons produced per worm showed the highest sensitivity to arsenic with a 56% reduction at the test concentration (Straalen and Rijin, (1998) assessed the effect of phenol on growth and reproduction of E. fetida after 56 days of growth in horse manure. A concentration of 3900 mg/l had no effect on the earthworms, but 4900 mg/l caused a 26% reduction in cocoon production.
It is also reported that a tannery sludge produced from tannery industry was toxic to E. fetida .
Adarsh et al., (2011)found out that 100% concentrated tannery sludge was toxic for the survival and reproduction of E. fetida . Therefore he mixed it with other organic waste like cattle dung to enhance the nutrient contents. Results showed that a minimum mortality rate and maximum biomass build up was recorded when sludge was mixed with cattle dung.
Khalil et al., (1996) also measured the mortality and cocoon production of porrectodea caliginosa species when exposed to various concentrations of cadmium, copper and zinc sulphate in an Egyptian soil. So far, a small number of research groups have been conducting experiments on the toxicity of organic compounds and pesticides to earthworms. As a result, there are a limited number of experimental designs in use to determine the lethal effect of these
30 compounds (Efrymson et al., 1997). Neuhauser et al., (1986) used the OECD artificial soil (pH
6) to assess the effects of 1, 2-Dichloropropane on survival of adults of four earthworms,
Perionyx excavatus , Eudrilus eugeniae , Eisenia fetida , and Allolobophora tuberculata . They determined the lethal concentration which was able to kill 50% of earthworms (LC50) after 14 days and found a decreased sensitivity in the order P. excavatus >E. fetida >A. tuberculata >E. eugeniae .
2.9.3. The Fate of Household Chemicals on On-site Sanitation systems
Household chemicals can be toxic to many organisms and to the environment at large. A report by EcoHealthy and Child Care shows that wide variety of toxic or hazardous chemicals are routinely used as ingredients for cleaning products (EHCC, 2006). It describes also out of the
85,000 synthetic chemicals in use today, only a small fraction has been individually tested for toxicity on macro-organisms.
The main reason for the poor performance of many domestic OSSs is due to the addition of household chemicals with bactericidal constituents (Gross, 1978). Some household products, such as ammonia, bleach, and laundry detergents, are intended to be poured down the drain.
Under normal use conditions, the chemicals found in these cleaning products pose a minimal risk to the environment because they are diluted in the septic tank or degraded in the leach field.
Some household products, however, contain chemicals that may harm the septic system or contaminate groundwater (Schwartz et al., 2004). If these chemicals enter a septic tank in large doses or concentrated amounts, they may reach concentrations that are toxic to the beneficial bacteria that normally breakdown components in wastewater (Kratzer, 2003). In most of the developing countries, dettol antiseptic, parazone and Mr.Muscle are used for cleaning of sanitation facilities and other household commodities.
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2.9.3.1. Chloroxylenol (dettol)
From the manufacturer company description, dettol disinfectant is an effective concentrated antiseptic solution that kills microbes and provides protection against germs which can cause infection and illness. It can also be used for antiseptic cleansing of minor wounds caused by cuts, bites, grazes, insect stings and for personal hygiene. This antiseptic chemical is widely distributed especially in developing world due to its cost effectiveness and effective performance in killing germs and bacteria. Looking at the ingredients of most antiseptics, dettol antiseptic disinfectant is 4.8%w/v and contains Chloroxylenol as an active component (GPO, 2013).
Chloroxylenol is an antimicrobial chemical compound recycled to control bacteria, algae, and fungi in adhesives, emulsions, paints, and wash tanks (Dunmore et al., 2011). It is extremely toxic to a wide variety of bacteria, fungi and other microbes; however, it is only a mild irritant to humans and other animals (http://envirosi.com/chloroxylenol-toxicology ). Dettol antiseptic has some basic chemical and physical properties as shown Table 2-2.
Table 2-2: Physical and Chemical Properties of Chloroxylenol (dettol)
Physical and chemical Properties Description Colour colourless Physical state Liquid Odour Pine/phenolic Odour threshold Not available
Chemical formula C8H9ClO Melting point Not available Boiling point Not available pH 9.5(alkaline) Vapour pressure Not available
Source: (http://www.rbnainfo.com/msds/us/dettol-us-English.pdf )
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2.9.4.2. Sodium Hypochlorite (Parazone)
Among all the chemical cleaning agents, Sodium Hypochlorite, NaOCl (commonly known as liquid bleach) is the most commonly used (OSHC, 2003). It is an inorganic oxidizing agent found in most household cleaning chemicals. It is registered in the Toxic Substances Control Act
(TSCA) Chemical Substance Inventory as hypochlorous acid, sodium salt (C1HO-Na) and is identified with the Chemical Abstracts Service (CAS) Registry Number 768 1-52-9.
As per the manufacturing company data and safety sheet description, Parazone Bleach is the thickest, freshest and most powerful bleach used in bathrooms and kitchens to kill bacteria, germs, and other microorganism. Parazone kills up to 99.9% of germs and can create a clean and safe environment for most household bathrooms and kitchens. Sodium hypochlorite (NaOCl) is the powerful active component found in parazone bleach together with other compounds like sodium hydroxide and perfume (<1%) in composition (Aadvark, 2013).
Some of the physical and chemical properties of sodium hypochlorite (parazone) are listed in
Table 2-3.
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Table 2-3: Physical and Chemical properties of Sodium Hypochlorite (parazone)
Physical & chemical properties description
Colour Greenish Odour Chlorine odour like household bleach Physical state Liquid
Density 1.21 g/cc @20 ℃ Solubility in water Complete pH 12(Alkaline) % Volatility Do not apply
Temperature of decomposition 40 ℃ Source: http://www.mexichem.com/English/docs/hojas_seguridad/msd sodium -hypochlorite- coatza.pdf )
2.9.4.3. Lactic acid (Mr. Muscle)
Mr. Muscle toilet Power is a range of powerful toilet cleaners which can kill 99 % of viruses and bacteria. It is a bathroom concentrated liquid cleaner in a convenient trigger pack formulated to remove microorganisms. Lactic acid is the most common active ingredient in Mr Muscle in addition to other alcohols (ethanol). Table 2-4 shows the characteristics of Mr. Muscle.
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Table 2-4: Physical and Chemical properties of Lactic acid (Mr. Muscle)
Physical and chemical Description properties pH 8 (basic) Physical state liquid Odour Not detected Colour Bluish orange Density 8.35 g/cc Solubility Fully miscible with water Source: http:// www.astleys.co.uk /
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CHAPTER THREE
3.0. RESEARCH METHODOLOGY
3.1. Introduction
Under this section the approaches to meet the main goal of the study through collection and identification of test animals (earthworms), description of test chemicals and the respective concentrations are presented. Finally the general experimental procedures and the experimental set up descriptions are presented.
3.2. Collection and Identification of Earthworms
For the aim of toxicity test, African species of earthworms (Eudrilus eugeniae ) were collected and cultured with organic waste. At the beginning, eudrilus eugeniae were collected carefully from Accra, (the capital of Ghana) composting digester manually and transported to
Kumasi for further culturing and growth. Due to their high potential in organic waste degradation and rapid reproduction rate, Eudrilus eugeniae were selected for the test and further cultured near the Water and Environmental quality laboratory of Kwame Nkrumah University of Science and Technology (KNUST) campus.
The experimental earthworms (eudrilus eugeniae) were cultured (Figure 3-1) in 18 litre plastic containers with holes drilled at the bottom to prevent water stagnation and maintain a moisture content conducive for the growth of earthworms. To make sure the earthworms could not escape from the culturing plastic container through the bottom drilled holes; a rubber mesh was fixed at the bottom of the container. The plastic container was left uncovered with a net meshing to allow air circulation within the vermibed. Earthworms ( eudrilus eugeniae ) were monitored under a moisture content of 55-70%
36 and pH range of 6.5-7.Blackwater was added as a feed for the growth of earthworms ( eudrilus eugeniae ) every 7 days. Water was periodically sprinkled on the plastic box to moisten the blackwater (culturing media). Earthworms were kept under such conditions inside the plastic container for 3 months before the main laboratory test was carried out.
Figure 3-1: Culturing of Earthworms ( Eudrilus eugenaie ) 3.3. Description of Test chemicals
The following three most common bactericidal test chemicals were selected for the toxicity test of earthworms ( eudrilus eugeniae).
1. Chloroxylenol (dettol);
2 .Sodium hypochlorite (parazone) and
3. Lactic acid (Mr.Muscle)
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The test chemicals were selected because of their wide application in urban poor areas of
Africa, including Ghana. Most households in Ghana use the chemicals mentioned earlier to clean their sanitation facilities due to their accessibility in low cost and good ant-microbial potential.
All the test chemicals were purchased from supermarkets and diluted to prepare the concentrations.
3.3.1. Test Chemical Concentrations
Five different concentrations of each toxic test chemical namely; Chloroxylenol (dettol solution), sodium hypochlorite (parazone solution) and lactic acid (Mr.Muscle solution) were applied for toxicity resistant test of earthworms (eudrilus eugeniae) . The concentrations were diluted and prepared based upon the usage instructions prescribed by the manufacturing companies. A range of concentrations were also prepared outside the stipulated, based on household user practices in low income areas of Ghana (i.e. concentrations below and above the recommended values by the manufacturing companies) (Table 3-1).
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Table 3-1: List of Applied Concentrations
Type of test chemicals Applied concentration mg/ml ml/ml 0.3 20/3000 0.6 40/3000 Chloroxylenol( Dettol) 1.2 80/3000 2.4 160/3000 5 320/3000 0.6 40/3000 Sodium hypochlorite(Parazone) 1.3 80/3000 2.5 160/3000 5 320/3000 9 640/3000 0.7 100/3000 1.3 200/3000 Lactic acid(Mr.Muscle) 2.4 400/3000 4 800/3000 7 1600/3000
3.4. General Description of Experimental Set up and Feed
To test the earthworms ( eudrilus eugeniae ) by different chemical concentrations, vermibed boxes were prepared from wooden material. Five wooden boxes for each single chemical concentration of each test chemical (i.e. chloroxylenol, sodium hypochlorite and lactic acid) and the controls with a total of 17 boxes. A single vermibed box is 50cm long, 17 cm wide and 20 cm deep with a volume of 17 litres (Figure 3-2).
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20cm
50cm
Figure 3-2: The Dimension of a Single Vermibed Box The vermibed boxes were prepared based on a scale of the actual biofil digester with
(1.8m*0.6m*0.6m) scaled down by a factor of 3. A rubber mesh was fixed at the bottom to allow free draining of the liquid from the feed and at the top to prevent entry of other insects and invertebrates after the addition of blackwater. All the boxes were arranged on the two wooden frames of length 2m and width 55 cm. Small plastic bowls were placed under each vermibed box to receive the liquid draining from the feed during the experiments. Figure3-3 represents the alignment of some of the vermibed boxes on the prepared table over the 21 days of exposure time .
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Figure 3-3: The Schematic Diagram of the Set up 3.4.1. Experimental Procedures
100 grams (dry weight) of coconut fibre was introduced onto the vermibed boxes and spread onto the rubber mesh (bottom surface of the boxes) carefully. 400 grams of fresh blackwater was collected from Ayigya Zongo, a small community about 8km from KNUST campus and mixed with the respective chemical concentrations listed under table 3-1. Finally the feed (Test chemical mixed with blackwater) added to each vermibed box.
Blackwater without test chemicals added to the two controls prepared for the test;
1. Control without earthworms (C 0) and
2. control with earthworms(C 1) as performed by (Lister et al., 2011).
After spiking each concentration of the toxicants, the vermibeds (i.e. the wooden container with coconut fiber) was left free for 24 hours to allow initial equilibration with the substrate constituents added for the test.
41
Prior to the addition of earthworms, 82.4 grams of loamy soil was added in each of the vermibed boxes(including the controls) to let earthworms adapt the system for the initial time as recommended by (Norbu, 2002). Afterwards groups of eight adult earthworms (a total of 128 earthworms) were introduced into each vermibed boxes including the control (C 1), and monitored for 21 days. Tap water was sprinkled over the vermibeds every day to maintain the moisture content constant. During the experiments, waste digesters ( eudrilus eugeniae) allowed to digest the feed (blackwater mixed with various chemical concentrations) over the 21 days of exposure.
After every 7 days of exposure, (7, 14 and 21 days) the weight of each vermibed box was measured and tap water was sprayed to replace any evaporation loses and the earthworms removed. The numbers as well as the weight change of survived earthworms were measured at the end of each week. Bodyweight change was calculated as the difference between the current and original earthworm weight recorded by survived earthworms in each week. After taking samples in each week the survived earthworms along with vermibeds were returned back to the original seat for next sampling.
After 21days of exposure, earthworms were sorted and surviving worms counted.
Vermibeds were sieved with 2 mm mesh size sieve and any cocoons present were counted and used to calculate cocoon production rate as cocoons per surviving worm per week.
3.5 .Statistical Analysis
Various statistical analyses of the experimental data were performed by using Microsoft
Excel 2007. Analysis of variance (ANOVA) was used to evaluate the significance of concentration variation on earthworm survival rate at 95% confidence interval and concentration effect on earthworms’ contaminant removal potential. T-test also used to check the significance
42 of the means of earthworms survival rate recorded in each week. It also used to check the significance of contaminant removals and body weight changes between the weeks by earthworms
The correlation test was used to determine the effect of increasing concentration on earthworm survival potential and contaminant removal efficiency after applying of various concentrations.
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CHAPTER FOUR
4.0. RESULTS AND DISCUSSIONS 4.1. RESULTS This section presents the results of experiments undertaken to assess the effects of different chemical constituents on the performance of the biofil toilet technology to treat blackwater. It outlines the characteristics of blackwater used for the experiments; the survival of organisms to chemical applications; and their recovery potential after the chemical application. The performance of the vermibed is also presented by characterizing residual biosolids after solid- liquid separation and application of chemical constituents to determine the contaminant removals in the stabilized sludge.
4.1.1. Characteristics of Blackwater
Both the physico-chemical and microbiological parameters of the blackwater were analysed. The feed blackwater was very strong. It had high BOD 5, COD, TSS, TDS and Total carbon values (Table 4-1). It also had high concentrations of E. coli, Total coliforms and helminth eggs of 2.30E+09 CFU/100ml , 3.80E+09 CFU/100ml and 725 (HO)/gTS respectively.
The average pH recorded in the blackwater was 6.8. Nutrient contents of blackwater which are the most important parameters for agricultural purposes were measured as total nitrogen 1.9 %
(19000 mg/l), total phosphorus 1.8 % (19000 mg/l), potassium 0.5% (5000 mg/l) and total carbon 44.1% (441000 mg/l). These are compared with the recommended values for land application.
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Table 4-1: Characteristics of Blackwater
Waste water Raw Parameters Blackwater
pH 6.8 Temperature ( ℃) 30.7
TSS (mg/l) 5700
TDS (mg/l) 3560
BOD5 (mg/l) 870
COD (mg/l) 1814
TN (%) 1.9
TP (%) 1.8
K (%) 0.5
T.C (%) 44.1
E. coli (CFU/100ml) 2.30E+09
Total coliforms (CFU/100ml) 3.80E+09
Helminth eggs (HO/g TS) 725
To determine the possible contribution of the BTT reducing the negative health defects of its contents, the helminth egg contents were further characterised in the blackwater. It was realized that the proportion of Ascaris was dominant (38%); followed by Hookworms (35%);
Teania sp. (24%) and strongyloides (3%) as shown in Figure 4-1.
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strongyloides Ascaris 3% lumbricoides 38%
Hookworms 35%
Teania spp 24%
Figure 4-1: Percentages of D istribution of Helminth ova in raw Blac kwater
4.1.2. Survival of E arthworm ( eudrilus eugeniae )
There was no mortality recorded for the whole 21 days of exposure in the control test.
4.1.2.1. Effect of Chloroxylenol (dettol) on Eudrilus eugeniae
During the first 7 days after applic ation of chloroxylenol: 8(100%), 7(87.5%), 4(50%),
3(37.5%) and 2(25%) of the worms out of 8 survived when exposed to the various concentrations of 0.3, 0.6, 1.2, 2.4 and 5mg/ml chloroxylenol respectively. Only the concentration at 0.3mg/ml did not record any mortality within the 7 days exposure alongside the control (Figure 4 -2).
9 8 7 6 5 y = 0.433x 2 - 3.445x + 8.430 4 R² = 0.951 3 2
Earthwormssurvived 1 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 Concentration of chlrxylenol (mg/ml)
Figure 4-2: Effect C hloroxylenol on the survival of Eudrilus eugeniae after 7 days
46
Similarly, after 14 days of the application of chloroxylenol concentrations; 6(75%),
5(62.5%), 3(37.5%), 2(25%) and 2(25%) of earthworms were able to survive with 0.3, 0.6, 1.2,
2.4 and 5 mg/ml concentrations respectively (Figure 4-3).
9 8 y = 0.552x 2 - 3.816x + 7.368 7 R² = 0.956 6 5 4 3 2 1 Earthwormssurvived 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 concentration of chloroxylenol (dettol) (mg/ml)
14 days 21 days
Figure 4-3: Effect of Chloroxylenol on Eudrilus eugeniae Survival after 14 and 21 Days
After 21 days of exposure, the concentrations of chloroxylenol did not cause any lethal effect on the earthworms. The number of earthworms that survived were 6(75%), 5(62.5%),
3(37.5%), 2(25%) and 2(25%) at concentrations of 0.3, 0.6, 1.2, 2.4 and 5mg/ml respectively, same as recorded during the 14 days exposure.
4.1.2.2. Effect of Sodium Hypochlorite (parazone) on Eudrilus eugeniae
After the first 7 days of experiment: 7(87.5%) and 6(75%) of the earthworms survived at
0.6 and 1.3 mg/ml concentration of sodium hypochlorite respectively. However, no survival of earthworms was recorded at concentrations 2.5,5 and 9 mg/ml. Hence 2.5mg/ml concentration could be considered as the lethal concentration that was able to kill 100% of earthworms
(eudrilus eugeniae).
47
9 8 7 y = -3.208x + 8.778 6 R² = 0.919 5 4 3 2 1 Earthwormssurvived 0 0 0.5 1 1.5 2 2.5 3 Concentration of sodium hypochlrite (parazone) (mg/ml)
Figure 4-4: Effect of Sodium Hypochlorite on Eudrilus eugeniae survival after 7 Days
After 14 days of exposure, 5(62.5%) and 4(50%) of earthworm survival was recorded at
0.6 and 1.3 mg/ml concentrations of sodium hypochlorite respectively.
9 8 7 6 y = -3.034x + 7.588 5 R² = 0.973 4 3 2 1 0 Earthwormssurvived 0 0.5 1 1.5 2 2.5 3 Concentration of sodium hypochlorite (parazone) (mg/ml) 14 days 21 days
Figure 4-5: Effect of Sodium Hypochlorite on Eudrilus eugeniae Survival after 14 and 21 Days
Earthworms that survived after the 14 days of experiment stayed alive without any lethal effect by any of the applied concentrations. In effect, 62.5% and 50% of earthworms were able to survive after 21 days of exposure at 0.6 and 1.3 mg/ml of sodium hypochlorite respectively .
4.1.2.3. Effect of Lactic acid (Mr Muscle) on Eudrilus eugeniae
After 7 days of chemical application, 7(87.5%), 7(87.5%), 6(75%) and 3(37.5%) of earthworms ( eudriluseugeniae ) were able to survive at 0.7, 1.3, 2.4 and 4mg/ml respectively. At
48
7 mg/ml, earthworms were not able to resist the toxicity effect resulting in 100% mortality after the 7 days of exposure.
9 8 7 6 y = -1.172x + 8.175 5 R² = 0.980 4 3 2 1 0 Earthwormssurvived 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 Concentrations of lactic acid(mr.muscle) (mg/ml)
Figure 4-6: Effect of Lactic acid on Eudrilus eugeniae Survival after 7 Days
Earthworms were able to survive at 7(87.5%), 6(75%), 5(62.5%) and 2(25%) treated with concentrations of 0.7, 1.3, 2.4 and 4 mg/ml respectively after 14 days of exposure. However, the concentrations did not cause 100% mortality effect on earthworms during this time (Figure 4-7).
8 6 y = -1.172x + 7.675 R² = 0.969 4 2 0 Earthworms survived 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 Concentrations of lactic acid ( mr.muascle ) (mg/ml) 14 days 21 days Figure 4-7: Effect of Lactic acid on Eudrilus eugeniae survival after 14 and 21 Days
After 21 days of exposure, no mortality was recorded on earthworms and earthworms that survived after 14 days of exposure were able to survive after 21 days without experiencing any adverse effect by each of the concentrations (Figure4-7).
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4.1.3. Earthworm (eudrilus eugeniae ) Recovery Potential
4.1.3.1. Body Weight Change
Over the 7 days exposure, the earthworms also showed body weight losses with all the applied chemical concentrations.
1) Body Weight Change of Earthworms Exposed to Chloroxylenol
Earthworms tested under the control (C 1) increased their body weight by 22.1% after the 7 days experiment while those treated by chloroxylenol reduced body weight by 0.7% and 25.6% at concentrations of 0.3 mg/ml and 5 mg/ml respectively (Figure 4-8).
60 50 40 30 20 10 0 -10 7 14 21
Body weightBody change(%) -20 Exposure time (Days) -30 control 0.3 mg/ml 0.6 mg/ml 1.2 mg/ml 2.4 mg/ml 5 mg/ml
Figure 4-8: Effect of Chloroxylenol on Body Weight Change of Eudrilus eugeniae
There was a general increase in body weight after the 7 days exposure. A maximum body weight gain of 35.8% was attained by the earthworms under the control while a 34.4% weight gain was recorded by the earthworms treated by various concentrations of chloroxylenol after 14 days of exposure (Figure 4-8) . Earthworms treated at a concentration of 5mg/ml after 21 days of exposure, further increased their body weight by 31.2% and 38.7% at a concentration of 0.3 mg/ml; while in the control earthworms were able to increase by 46.9%.
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2) Body Weigh Change of Earthworms Exposed to Sodium Hypochlorite
The surviving earthworms treated by sodium hypochlorite concentrations after the first 7 days of exposure were not able to either increase or maintain their original body weight. A body weight reduction by 15.7% and 28.5% were observed on the survived earthworms treated with
0.6 and 1.3 mg/ml concentrations respectively as compared to earthworms tested in the control
(C1) whose their body weight increased by 22.1% (Figure 4-9).
60 40 20 0 -20 7 14 21 -40 Exposure time (Days)
Body weight weight Body change(%) control 0.6 mg/ml 1.3 mg/ml
Figure 4-9: Effect of Sodium Hypochlorite on Body Weigh Change of Eudrilus eugeniae
After 14 days of exposure, earthworms started recovering from the toxicity effect by showing a gradual increase of body weight. The earthworms were able to gain body weight by
15.7% and 17.7% treated with concentrations of 1.3 and 0.6 mg/ml respectively as compared with 35.8% attained by earthworms in the control. Furthermore, as the exposure time increased to 21 days, earthworms’ body weight increased by 22.2% and 21.1% after treatment with concentrations of 0.6 and1.3 mg/ml respectively (Figure 4-9); while in the control earthworms were able to increase by 46.9%.
3) Body Weight change of Earthworms Exposed to Lactic acid (Mr.Muscle)
Earthworms after treatment with lactic acid decreased in body weight after 7 days of exposure. A body weight loss (-0.1%) was measured by earthworms tested with lactic acid
51
(Figure 4-10) compared to those exposed to chloroxylenol and sodium hypochlorite. The measured body weight loss by earthworms was statistically significant (p=0.03) with gradual increase of applied concentrations at 95% of confidence interval.
After 14 days of exposure the earthworms recorded a 4.1% and 29.5% weight gain at 0.4 and 0.7 mg/ml respectively.
Similarly after 21 days of exposure, earthworms increased their body weight up to 32% compared to the body weight measured over the 14 days of exposure. The effect of each applied concentrations on the body weight gain is illustrated in Figure 4-10.
60
40
20
0
Body weigt weigt Bodychange(%) 7 14 21 -20 Exposure time(Days) control 0.7 mg/ml 1.3 mg/ml 2.4 mg/ml 4 mg/ml
Figure 4-10: Effect of Lactic acid on Body Weight Change of Eudrilus eugeniae
4.1.3.2. Characteristics of Biosolids and Contaminant Removal by Earthworms
This section presents the characteristics and nutrient contents of biosolids from the vermibeds after 21 days of exposure to the chemical constituents. For the entire chemical treatments and controls, the biosolid temperature ranged from 30.5 ℃ to 32.4 ℃ and pH from7.9-
8.1.
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1) Nutrient Contents of Biosolids (NPK and Total carbon)
In this study the total nitrogen, total phosphorus and potassium contents of the biosolids produced were found to be 2.6% total nitrogen (TN); 1.7% total phosphorus (TP), 0.4% potassium (k) and 23% total carbon (TC) by the control (C 1) with earthworms after 21 days of exposure.
Nutrients in the biosolid produced by earthworms exposed by chloroxylenol had total nitrogen (TN) within a range of 2.4-2.5%, total phosphorus (TP) 1.2-1.6 % and potassium from
0.3-0.4 % (Figure 4-11). There was a reduction of total carbon content in blackwater from 44.1% to 22.8 % and 28% at concentrations of 0.3 and 5 mg/ml respectively. The total carbon content increased with increase in chemical concentrations (Figure 4-11).
30
25
20
15
N,P,K and(%) TCN,P,K 10
5
0 control 0.3 1.2 5 concntration of chloroxylenol ( mg/ml ) TN(%) Tp(%) K(%) TC (%)
Figure 4-11: Nutrient Contents of Biosolids Produced by Earthworms Exposed to Chloroxylenol
The earthworms exposed to sodium hypochlorite also had nutrient contents of total nitrogen (TN) within ranges of 2.4%-2.7%, total phosphorus (TP) from 1.3% -1.5% and
Potassium (K) was found to be 0.5% by at concentrations of 0.6 and 1.3 mg/ml. The total carbon
53 content of blackwater increased to 26.3% and 26.4% at 0.6 mg/ml and 1.3 mg/ml application with sodium hypochlorite respectively (Figure 4-12).
30 25 20 15 10
N,P,K N,P,K and(%) TC 5 0 Ccontrol 0.6 1.3 Concentration of sodium hypochlorite (mg/ml) TN(%) Tp(%) K(%) TC (%)
Figure 4-12: Nutrient Contents of Biosolids Produced by Earthworms Exposed to Sodium
Hypochlorite
The nutrient contents of biosolids produced by earthworms exposed to lactic acid were recorded as; total nitrogen in a range of 2.1 to 2.2%, total phosphorus (TP) was 1.2-1.3% and potassium was found to be 0.2%. The total carbon content was 25.4% at concentration 0.7 mg/ml, 29.1% at concentration 2.4 mg/ml and 27% at concentration of 4 mg/ml. The availability of total carbon content in biosolids increased with concentration of lactic acid (Figure 4-13).
40
30
20
10 N,P,K and(%) TCN,P,K 0 control 0.7 2.4 4 Concentration of lactic acid (mg/ml) TN(%) Tp(%) K(%) TC (%)
54
Figure 4-13: Nutrient Contents of Biosolids Produced by Earthworms Exposed to Sodium Hypochlorite
4.1.3.3. Pathogen Removal
1) E. coli Removal
2.2 log and 4.7 log removal of E. coli were recorded in the vermibeds without earthworms in the control (C 0) and with earthworms (C 1) respectively. Vermibeds spiked with chloroxylenol recorded an E. coli concentration within a range of 4.3-4.5 log. The log removals by the earthworms exposed by various applied concentrations of chloroxylenol were also similar with the E. coli log removal observed in the control (C 1).The effect of various concentrations of chloroxylenol on earthworms is shown in Figure 4-14.
5 4 3 2 1 0
E-coli log removal E-coli 0 0.3 1.2 5 Concentration of chlorxylenol (dettol) (mg/ml) E-coli log removal C0 C1
Figure 4-14: Effect of Chloroxylenol on Earthworms E. coli Removal
On the other hand, vermibeds spiked with sodium hypochlorite recorded a 4.3 and 3.5 log removal after exposure with concentrations of 0.6 and 1.3 mg/ml respectively. A relatively poor log removal of E. coli was observed by sodium hypochlorite at concentration 1.3 mg/ml (Figure
4-15).
55
5 4 3 2 1 0
E-coli logremoval E-coli 0 0.6 1.3 Concentration of sodium hypochlorite) (mg/ml) C0 C1 E-coli log removal
Figure 4-15: Effect of Sodium Hypochlorite on Earthworms E. coli Removal
E. coli log removal after 21 days of exposure to lactic acid was between 4.2-4.4 (Figure
4-16).
5 4 3 2 1 0 E-coli removal E-coli log 0 0.7 2.4 4 Concentration of lactic acid (mr.muscle) (mg/ml) C0 C1 E-coli log removal
Figure 4-16: Effect of Lactic acid on Earthworms E. coli Removal
2) Total Coliforms Removal
4.1-4.6 log removals of total coliforms were achieved by earthworms exposed to chloroxylenol when treated with various applied concentrations (Figure 4-17). Log removal efficiency of earthworms decreased with gradual increase in applied concentration after 21 days of exposure.
However, it is not statistically similar (p=0.21) with increase in applied concentration at 95% of confidence interval.
56
5 4 3 2
removal 1
Total coliformsTotal log 0 0 0.3 1.2 5 Concentration of chloroxyloenol (mg/ml) C0 C1 total coliforms log removal
Figure 4-0-1: Effect of Chloroxylenol on Earthworms Total coliforms Removal
After 21 day exposure to sodium hypochlorite, a 4.1 and 3.4 log removals of total coliforms was recorded at concentrations of 0.6 and 1.3 mg/ml respectively (Figure 4-18). The total coliforms log removals obtained were statistically (p=0.03) similar with the gradual increase in applied concentrations.
5 4 3 2 1 removal 0
Total coliforms Total log 0 0.6 1.3 Concentration of sodium hypochllorite(parazone) (mg/ml) C0 C1 total coliforms log removal
Figure 4-0-2: Effect of Sodium Hypochlorite on Earthworms Total coliforms Removal
The earthworms exposed to lactic acid after 21 days of exposure were able to remove total coliforms by 4.1-4.3 logs when tested by various applied concentrations of lactic acid (Figure 4-
19).
57
5 4 3 2
removal 1 0 Total coliforms Total log 0 0.7 2.4 4 Concentration of lactic acid (mr.muscle) (mg/ml)
C0 C1 total coliforms log removal
Figure 4-0-3: Effe ct of Lactic acid on E arthworms Total coliforms R emoval
3) Helminth ova Removal
After 21 days of exposure, the Helminth ova concentration was reduced to 61 HO/gTS representing a 91% removal by earthworms in the control test (Figure 4 -20). Earthworms exposed to test chemical, chloroxylenol were able to remove the Helminth ova content of blackwater to142 HO/gTS (80% removal), 160 HO/g TS (78% removal) and 308 HO/gTS (58% removal) when treated with applied concentrations at 0.3, 1.2 and 5 mg /ml respectively (Figure
4-20).
5mg/ml Control 58%(308HO/ 92%(61HO/g gTS) TS) 0.3mg/ml 80%(142HO/ gTS)
1.2mg/ml 78%(160HO/ gTS)
Figure 4-20: Effect of Chloroxylenol on Earthworms Helminth ova R emoval
Helminth ova concentration was also reduced by earthworms ( eudriluseugeniae ) when exposed to sodium hypochlorite. A 95 HO/g TS (87% removal) and 428 HO/g TS (41% removal) of
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Helminth ova removal was achieved when treated with 0.6 and 1.3 mg/ml respectively (Figure 4 -
21).
Control 92%(61 HO/gTS)
0.6mg/ml 87%(95 Ho/gTS) 1.3mg/ml 41%(428 HO/gTS)
Figure 4-21 : Effect of Sodium Hypochlorite on Earthworms Helminth ova R emoval
Relative to chloroxylenol and lactic acid, poor reduc tion of helminth ova (41%) was observed by earthworms exposed at concentration of 1.3mg/ml.
Similarly, 123 HO/gTS (83% removal), 145 HO/gTS (80% removal) and 350 HO/gTS (52% removal) of Helminth ova was achieved by earthworms exposed to lactic acid when t reated with concentrations of 0.7, 2.4 and 4 mg/ml respectively (Figure 4 -22). The Helminth ova concentration recorded after 21 days of exposure was statistically (p=0.05) similar with gradual increase in applied concentration.
4mg/ml Control 52%(350HO/ 92%(61HO/g gTS) TS) 0.7mg/ml 83%(123HO/ gTS)
2.4mg/ml 80%(145HO/ gTS)
Figure 4-22: Effect of Lac tic acid on Earthworms Helminth ova Removal
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4.1.3.4. Chemical Oxygen Demand (COD) removal
Earthworms treated with various applied concentrations of chloroxylenol were able to remove the chemical oxygen demand (COD) of the feed significantly. The feed was had a COD content of 1,814 mg/l.
After 21 days of exposure, COD was removed up to45% in the control test (C 0), however with the addition of earthworms in the control (C 1); the COD was further removed by 89%
(Figure 4-23). The earthworms exposed to chloroxylenol were able to remove up to 62% of COD after 7 days of exposure.
After 14 days of exposure better removal of COD was observed relative to the removal after 7 days (Figure 4-23).COD removal ranged between 68- 80% at various concentrations of chloroxylenol application. After 21 days of exposure, the earthworms were able to remove the
COD from blackwater up to 84% when treated with various concentrations of chloroxylenol.
After 21 days of exposure, the removal efficiency obtained by earthworms with chemical treatments of chloroxylenol were statistically similar (P=0.001) with increase in applied concentrations at 95% of confidence interval. Moreover, COD removals attained by earthworms were negatively correlated (-0.998) with gradual increase in applied concentrations.
60
100 80 60 40 20 COD % removal % COD 0 0 0.3 1.2 5 Concentration of chloroxylenol (dettol) (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-23: Effect of Chloroxylenol on Earthworms COD Removal
After treatment with sodium hypochlorite, earthworms showed significant COD removal from blackwater. After 7 days of exposure, relatively low removal of COD (50% and 30%) was attained by earthworms tested at 0.6 and 1.3 mg/ml concentrations respectively. However, after
14 days of exposure, 72 and 50% COD removal efficiency were achieved by earthworms treated at concentrations of 0.6 and 1.3 mg/ml respectively (Figure 4-24).After 21 days of exposure,
75% and 55% removal of COD were recorded by earthworms exposed with applied concentrations of 0.6 and 1.3 mg/ml respectively.
100 80 60 40 20
COD COD removal % 0 0 0.7 2.4 4 Concentration of lactic acid(mr.muscle) (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-24: Effect of Sodium Hypochlorite on Earthworms COD Removal
Similarly, earthworms exposed to lactic acid were able to remove the COD significantly. Up to
63% COD removal was achieved by earthworms after 7 days of exposure at various applied
61 concentrations. The COD removal efficiency of earthworms was statistically similar (P=0.001) with increase in applied concentration at 95% of confidence interval.
After 14 days of exposure, further removal of COD was achieved by earthworms treated with different concentrations. Earthworms were able to attain 84, 78 and 74% of COD removal from blackwater after treatment at concentrations of 0.7, 2.4 and 4 mg/ml respectively (Figure 4-
25). The COD removals by earthworms recorded over the 14 days of exposure was not statistically similar (T-test P=0.08) with that of the removals obtained during the 7 days of exposure at 95% of confidence interval.
After 21 days of exposure, 86, 82 and 80% COD removal by earthworms exposed at concentrations 0.7, 2.4 and 4 mg/ml respectively was observed (Figure 4-25).
100 80 60 40 20 COD % removal % COD 0 0 0.6 1.3 Concentration of sodium hypochlorite (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-25: Effect of Lactic acid on Earthworms COD Removal
4.1.3.5. Biological Oxygen Demand (BOD) Removal
After 21 days of exposure in the control tests, 75% removal of BOD was recorded in the control
(C 0) without the addition of earthworms, however earthworms were able to remove the BOD by
94% in the control(C 1) (Figure 4-26) .
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After 7 days of exposure, up to71% BOD removal was recorded by earthworms exposed to various concentrations of chloroxylenol. The removal efficiency by earthworms recorded at this time was statistically similar (p=0.002) with gradual increase of applied concentrations at 95% of confidence interval.
Similarly for 14 days exposure, further removal of BOD by 84, 83 and 76% was achieved by earthworms treated with the respective applied concentrations of chloroxylenol (Figure 4-
26).After 21 days of exposure, the earthworms were able to remove the BOD up to 89% by earthworms (Figure 4-26). At 95% confidence intervals, the BOD removals recorded after 21 days of exposure were statistically significant (p=0.03) with gradual increase of applied concentrations.
100 80 60 40 20 0 BOD % removal %BOD 0 0.3 1.2 5 Concentration of chloroxylenol(dettol) (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-26: Effect of Chloroxylenol on Earthworms BOD Removal
Earthworms exposed to sodium hypochlorite removed the BOD from the feed significantly.
After 7 days of exposure, 56% and 37% of BOD removal was observed by earthworms treated with concentrations of 0.6 and 1.3 mg/ml respectively, whereas after14 days with the respective applied concentrations, they were able to remove BOD by 79% and 72% (Figure 4-27).
63
After 21 days of exposure, earthworms degraded the blackwater and 83% and 77% BOD removal was achieved by earthworms treated with concentrations of 0.6 and 1.3 mg/ml respectively.
100 80 60 40 20 BOD % removal %BOD 0 0 0.6 1.3 comcentration of sodium hypochlorite( parazone) (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-27: Effect of Sodium Hypochlorite on Earthworms BOD Removal
Earthworms exposed to lactic acid with various applied concentrations were able to remove
BOD significantly. After 7 days of exposure, BOD was removed at 70%, 63% and 52% by earthworms treated with concentrations of 0.7, 2.4 and 4 mg/ml respectively. The BOD removal recorded after 7 days of exposure was statistically (p=0.004) similar with the gradual increase of applied concentrations at 95% of confidence interval. Similarly, up to 85% BOD removal was achieved by earthworms tested with the respective applied concentrations of lactic acid after 14 days of exposure. As the exposure time increased from7 days to 14 days, earthworms were able to show better performance in degradation of organic matter in blackwater. Up to 89% BOD removal was obtained by earthworms treated with various concentrations of lactic acid from blackwater in the biofil toilet technology (Figure 4-28).
64
100 80 60 40 20 0 BOD % removal %BOD 0 0.7 2.4 4 concentration of lactic acid(mr.muscle) (mg/ml) c0 c1 7 days 14 days 21 days
Figure 4-28: Effect of Lactic acid on Earthworms BOD Removal
4.1.3.6. Total Dissolved Solids (TDS) Removal
Total dissolved solids (TDS) were also significantly reduced by earthworms both in the controls and chemical treatments. In the control test without earthworms (C 0), 81% TDS removal was recorded. Whereas the earthworms in the control (C 1) removed the TDS content of blackwater and attained up to 96% removal (Figure 4-29).
Earthworms exposed to chloroxylenol were also able to reduce the TDS content of blackwater significantly up to 66% by earthworms when treated at 0.3 mg/ml concentrations after 7 days of exposure. The earthworms were able to remove up to 83% TDS after 14 days of exposure. After
21 days of exposure, 92% TDS removal and 83% TDS removal was achieved by earthworms tested by applied concentrations of 0.3 and 5 mg/ml respectively. The effect of chloroxylenol
(dettol solution) on earthworms in TDS removal efficiency after 21 days of exposure time is illustrated in Figure 4-29.
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100 80 60 40 20 TDS % TDS removal 0 0 0.3 1.2 5 Concentration of chloroxylenol (mg/ml) C0 C1 7 days 14days 21days
Figure 4-0-4: Effect of Chloroxylenol on Earthworm in TDS Removal
Earthworms exposed to sodium hypochlorite (parazone solution) were also able to remove the
TDS from blackwater significantly. It was able to remove the TDS up to 60% and 53% by earthworms tested with 0.6 and 1.3 mg/ml concentrations respectively whereas 83% and 75 % removals were attained by earthworms after 14 days of exposure. The 14 days removals of TDS done by earthworms were statistically significant (T-test, P=0.007) with the 7 days of removals achieved by earthworms at 95% of confidence interval. After 21 days of exposure, earthworms were free from toxicity effect and able to remove the TDS further by 86% and 82% treated by
0.6 and 1.3 mg/ml concentrations respectively (Figure 4-30).
100 80 60 40 20 TDS % TDS removal 0 0 0.6 1.3 Concentration of sodium hypochlorite(parazone) (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-30: Effect of Sodium Hypochlorite on Earthworms TDS Removal
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After 7 days of exposure, 62%, 58% and 55% TDS removal was obtained by earthworms exposed with concentrations of 0.7, 2.4 and 4 mg/ml respectively. The TDS removals recorded during this time were statistically similar (P=0.004) with the gradual increase of applied concentrations at 95% of confidence interval.
After 14 days of exposure time compared to the 7 days of removal, 80%, 75% and 72% removal was attained by earthworms tested at concentrations 0.7, 2.4 and 4 mg/ml respectively. Similarly after 21 days of exposure, 88%, 85% and 83% TDS removal was achieved by earthworms exposed with applied concentrations of 0.7, 2.4 and 4 mg/ml respectively (Figure 4-31).
100 80 60 40 20 0 TDS % TDS removal 0 0.7 2.4 4 Concentration of lactic acid(mr.muscle) (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-31: Effect of Lactic acid on Earthworms TDS Removal
4.1.3.7. Total Suspended Solids (TSS) Removal
A TSS removal of 79% was achieved in the control test by micro-organisms without the involvement of earthworms (C 0) (Figure 4-32). With the introduction of earthworms in the control test (C 1), up to 96% removal of TSS was achieved.
After 7 days of exposure, earthworms were able to remove up to 69% TSS from blackwater by earthworms tested with different concentrations of chloroxylenol. Similarly after
14 days of exposure, 85% TSS removal from blackwater was observed by earthworms treated with various concentrations. At 95% of confidence interval, the TSS removals recorded over the
67
14 days of exposure were statistically similar (T-test=0.04) with the removals recorded over the
7 days of exposure time.
After 21 days of exposure, earthworms were able to remove the TSS up to 92% from blackwater after treatment with various concentrations. The earthworms recovered from the effect of toxicity experienced over the 7 and 14 days of exposure and were able to digest the organic content of suspended solids in blackwater. However, the TSS removal efficiency of earthworms decreased with gradual increase of applied concentrations (Figure 4-32).
100 80 60 40 20 TSS TSS removal % 0 0 0.3 1.2 5 Concentration of chlorxylenol (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-32: Effect of Chloroxylenol on Earthworms TSS Removal
After 7 days of exposure, 63% and 54% TSS removals were attained by earthworms after being tested with 0.6 and 1.3 mg/ml concentrations respectively. Lower TSS removals were achieved by earthworms tested with 0.6 and 1.3 mg/ml compared to both controls (C 1) and (C 0). After 14 days of exposure, TSS removal of 84% and 82% were achieved by earthworms tested with the respective sodium hypochlorite concentrations. Earthworms further removed the TSS from blackwater after 21 days of exposure by 89% and 86% after being tested with 0.6 and 1.3 mg/ml concentrations (Figure 4-33).
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100 80 60 40 20 TSS % removal TSS % 0 0 0.6 1.3 Concentration of sodium hypochlorite(parazone) (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-33: Effect of Sodium Hypochlorite on Earthworms TSS Removal
Smilarly, after 7 days of exposure,up to 67%TSS removal was achieved by earthworms tested with lactic acid concentrations compared to the controls (C 0) and (C 1). (Figure 4-34).Also, after
14 days of exposure, earthworms removed the TSS up to 91% after being treated with applied concentrtions of lactic acid. The TSS removals obtained over the 14 days exposure were stastsitcally significant (T-test, p=0.003) with that of removals obtained over the 7 days of exposure at 95% of confidenc interval.Earthworms further removed the TSS content from blackwater up to 94% after 21 days of exposure tested by various concentrations. The removals of TSS obtained were stastistically similar with the gradual increase of applied concentrations.
100 80 60 40 20 TSS % removal TSS % 0 0 0.7 2.4 4 Concentration of lactic acid (mg/ml) C0 C1 7 days 14 days 21 days
Figure 4-34: Effect of Lactic acid on Earthworms TSS Removal
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4.2. DISCUSIONS
4.2.1. Characteristics of the Experimental Feed
The physico-chemical and microbiological characterization of the feed blackwater was measured before spiking on the vermibed to be used as a baseline to determine the level of contaminant removal in the blackwater by the earthworms after the 21 day exposure to the chemical constituents.
There are varying characteristics of blackwater reported by various researchers. For instance, in
Sweden, a study done by Coquin, (2005) on fresh blackwater from household toilets showed a
COD concentration of 1,900 mg/l, BOD 740 mg/l, TSS 2,100 mg/l, total nitrogen 170 mg/l and total phosphorous of 22 mg/l. Another study conducted on blackwater from Germany also showed an average COD of 8,060 mg/l, TSS 6,530 mg/l, total nitrogen as high as 1,495 mg/l and total phosphorous of 175 mg/l (Wendland, 2008). Different researches agreed that the characteristics and composition of blackwater varies from society to society and from country to country depending on the dietary components and prevailing environmental conditions( Kuffour et al., 2013;Trondel, 2010). There is little literature on the characteristics of blackwater in Ghana and Africa as a whole. For the purpose of this study, characteristics of the backwater were not compared but only used as a baseline data to determine removal efficiencies.
4.2.2. Physico-Chemical Characteristics of the Feed
The average pH of the feed blackwater (6.8±0.1) suggested that the blackwater was conducive for various microbial reactions (Gnanaprakasam et al., 2013). BOD and COD concentrations are used to determine the levels of organic and inorganic contaminant removal by the earthworms in the presence of the chemical constituents.
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Macro-nutrients need to be recovered from sewage sludge and biosolids since they are the main source of fertilizers that can be applied for soil conditioning in agricultural sector. The high carbon content of the blackwater recorded can be attributed to the high dietary content of food as reported in the diet of people in most developing countries in the form of roughages and carbohydrates (Kuffour et al., 2013). In addition, tissue paper as a cleansing material can contribute to the high carbon content.
4.2.3. Microbiological Characteristics of the Feed
The pathogenic contents of blackwater which are the main health indicator parameters in many countries (Fidjel, 2010) were analysed.The concentration of Helminth ova in the feed was 725
HO/g Ts which fell within the upper level of the range recorded by (Jimenez-Cisneros, 2008).In their study, they reported Helminth ova numbers of 70-735HO/g TS for faecal sludge in developing countries and 76 HO/g TS particularly in Ghana.Controlling of Helminth ova in urban poor areas is challenging due to its existence in high content and difficulties in surveying such areas regularly(Jimenez-Cisneros, 2008).
4.2.4. Survival Rates of Earthworms ( eudrilus eugeniae )
The survival rates were determined based on the standard recommendation by the Organization for Economic Co-operation Development (OECD), which stipulates less than 10% mortality(OECD, 1984). Earthworms ( eudrilus eugeniae ) treated in the control responded to gentle mechanical stimulus to their front end throughout the whole experiment and thus were considered as alive (OECD, 1984).
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4.2.4.1. Effect of Chloroxylenol solution (Dettol) on Eudrilus eugeniae
The Analysis of variance (ANOVA) single factor test suggested that, the survival rate of earthworms during the first 7 days of exposure was statistically similar (p=0.02) with gradual increase in the applied concentrations at 95% of confidence interval. This implies that increasing the chloroxylenol concentration could not cause different effect on survival of earthworms.
However, the correlation test shows that the survival of earthworms is inversely correlated (-
0.885) with the gradual increase of applied concentrations. This shows that increasing of the applied concentrations resulted in mortality and reduction of earthworm population over the 7 days of exposure. Earthworm survival rate recorded at 14 days experimentation was statistically different from that recorded during 7 days exposure time (T-test, p=0.118) at 95% of confidence interval. The applied concentrations had different effects on survival of earthworms after the 14 days exposure compared to the 7 days of exposure.
The earthworms that survived over the 14 days exposure stayed alive without any lethal effect after 21 days of experiment. This might be either that the applied concentrations of chloroxylenol lost its toxicity strength or earthworms adapted to the concentrations and started digesting the feed (blackwater). The number of earthworms that survived during the 14 days of exposure were statistically different (p=0.05) with increase in applied chloroxylenol concentrations at 95% confidence interval. This shows that the effect of various applied concentrations on earthworms were different on earthworms’ survival potential. As the applied concentration increased, the survival potential of earthworms’ decreased. The number of earthworms that survived over the
14 days of exposure were also inversely correlated (-0.791) with increases in applied concentrations.
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The test chloroxylenol did not cause 100% lethality/mortality effect on the earthworms over the
21 days of exposure with the different concentrations. The maximum concentration of 5mg/ml only caused 75% mortality at the end of the experimental period. A similar trend in earthworm mortality test was observed by VanGestel et al., (1988) who observed the depreciation in the toxicity effect of the chemical with time.Neuhauser and Callahan, (1990) also recorded a reduced effect of toxicity with increase in exposure time.
4.2.4.2. Effect of Sodium Hypochlorite (parazone) on Eudrilus eugeniae
The number of earthworms that survived during the 7 days exposure were statistically different
(P=0.07) with increasing concentrations of sodium hypochlorite. The gradual increase of applied concentrations resulted in different mortality/survival of earthworms. In addition, the correlation test showed that earthworm survival under 7 days of experiment was inversely correlated (-
0.959) to the gradual increase of concentrations. The study suggested that 2.5 mg/ml caused
100% mortality effect on earthworms representing a lethal concentration for earthworms under the test condition.
The analysis of variance (ANOVA) single factor test showed that earthworm survival was statistically different (p=0.12) with the gradual increase in concentration of sodium hypochlorite. This indicates that the different applied concentrations caused different effect on earthworm survival at 95% confidence interval in the 14 days exposure. Earthworms survival recorded was inversely correlated (-0.986) with increasing concentrations .
The number of earthworms that survived in the 14 days exposure was statistically (0.09) different from that recorded over the 7 days of exposure. Moreover, the correlation test during
73 the 14 days exposure (-0.986) was higher than that recorded in 7 days (-0.959). This proves that fewer earthworms survived over the 14 days of exposure compared to the 7 days of exposure .
The earthworm population inside the biofil digester was highly affected with the concentrations of sodium hypochlorite over the 7 and 14 days of exposure time.
4.2.4.3. Effect of Lactic acid (Mr. Muscle) on Eudrilus eugeniae
The number of earthworms that survived were statistically different (p=0.14) with gradual increase in applied concentrations at 95% confidence interval. Earthworms ( eudriluseugeniae) survival was strongly inversely correlated (-0.99) with increase in applied concentrations of lactic acid.
Furthermore, earthworms survival recorded during the 14 days exposure was statistically different (p=0.61) with gradual increase of applied concentrations. The number of earthworms that survived after the 14 days of exposure was statistically similar (T-test, p=0.04) to that recorded after the 7 days exposure at 95% of confidence interval. This shows that the respective test concentrations were able to cause earthworm mortality as the exposure time was increasing from 7 to 14 days.
4.2.5. Recovery Potential of Earthworms (Eudrilus eugeniae )
To determine the recovery of earthworms ( eudrilus eugeniae ), the body weight change recorded over the 21 days of exposure and contaminant removal potential were used. After the application of the test chemicals, the survived earthworms may have adapted to the toxicity effect and digested the feed (blackwater) to show body weight change which is an indication of recovery potential of the survived earthworms (Otitoloju, 2005).
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Due to time factor, three representative concentrations out of the five applied concentration listed were used from each test chemicals in order to assess earthworms’ recovery potential from toxic effects of all the three test chemicals. For this reason test chemical concentrations: chloroxylenol- 0.3, 1.2 and 5 mg/ml; sodium hypochlorite - 0.6, 1.3 and 2.5 mg/ml and lactic acid - 0.7, 2.4 and 4 mg/ml were used for this experiment. However, for sodium hypochlorite the concentration 2.5 mg/ml caused 100% mortality on earthworms so data were collected from only two concentrations (0.6 and 1.3 mg/ml) over the 21 days of this experiment.
4.2.5.1. Body Weight Change
The result obtained suggests that earthworms were able to recover from the toxicity effect of the three chemicals after 14 days of exposure time with significant body weight growth and contaminant removal potential compared to the original body weights. The toxic chemical concentration declines processes like biodegradation and physiological change of earthworms; the earthworms might stay for some time without feeding and this results in body weight loss
(VanStraalen and Rijin, 1998).
Body weight loss increased with gradual increase of applied concentration, indicating that the toxicity effect of chloroxylenol was high at higher concentrations. Body weight loss recorded by earthworms treated with chloroxylenol over the first 7 days of exposure was statistically significant (p=0.002) with increase in applied concentration at 95% of confidence interval. The correlation test also showed that body weight loss was increasing (-0.999) with gradual increase in applied concentration. Earthworm body weight loss after 7 days of experiment may be due to the reduction of feeding as a result of the toxic effect of the feed Gomez-Eyleset al., (2009) by the earthworm migrating away from the feed.
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Body weight gain by earthworms after 14 and 21 days of exposure was statistically significant (p<0.001) with gradual increase of applied concentrations at 95% of confidence interval. The correlation test also showed that body weight gain was negatively correlated by (-
0.874) with increased in applied concentrations over the 14 days exposure time and by (-0.883) after 21 days of exposure. Hence, as the applied concentration increased gradually, the body weight gain attained by earthworms increased as exposure time increased. This suggests that the effect of chloroxylenol toxicity declined as the exposure duration increased. It has been reported that the pesticide toxicity effect on earthworms decreased through time and the earthworms increased their body weight growth (VanStraalen and Rijin, 1998).
Earthworms exposed to the various concentrations of test chemicals were able to recover from the toxicity effect through time by increasing the quantity of feed they can digest which resulted increase in body weight development and contaminant removal potential (Sinha et al.,
2010)
Similarly, Compared to other test chemicals, earthworms experienced body weight loss of -
28.5% which shows that the toxicity effect of liquid bleach/sodium hypochlorite/parazone on earthworms was very high over the 7 days of exposure. The correlation test also showed that earthworm body weight reduction had a maximum negative correlation (-1) with increase in concentration of sodium hypochlorite. At 95% of confidence interval, the effect of increased concentration was not statistically significant (p=0.069) on body weight loss of earthworms.
Body weight gain by earthworms after 21 days of exposure was statistically significant (p<0.03) with increased concentration at 95% of confidence interval. The correlation test also showed that body weight gain after 21 days of exposure was highly correlated (-0.997) with gradual increase in applied concentrations.
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The study therefore suggests that the last two weeks (i.e. after 14 and 21 days of exposure), earthworms (eudrilus eugeniae ) were able to recover from toxicological effect of the three test chemicals used. Body weight gain recorded on earthworms after 14 and 21 days of exposure was similar to the control test. This showed that as the time from application of test chemicals increased, the toxicity effect of each test chemical declined and as a result earthworms were able to digest the biosolids by feeding.
4.2.5.2. Performance of Contaminant Removal under Test Conditions
In addition to body weight change, the earthworms (eudrilus eugeniae ) found in both the control and chemical treatment vermibeds were able to degrade the black water significantly and changed it to biosolids (vermicast).
The results obtained agreed with Jilani, (2007) who worked on blackwater vermicomposting and documented pH value of vermicompost with ranges of 5.5-8.
1) Nutrient Contents
As the concentration increased gradually, earthworms’ potential in reduction of organic carbon content declined. This might be that the toxicity effects found in the feed (blackwater) prevented earthworms from degrading the organic content of total carbon present in blackwater. The various concentration effect of chloroxylenol on nitrogen, phosphorus, potassium and total carbon content of the biosolid can be seen in Figure 4-11. All the nitrogen, phosphorus, potassium and total carbon contents recorded by applied concentrations were statistically similar to the values measured in the control (p<0.05) at the 95% confidence interval. The nitrogen, phosphorus, potassium and total carbon contents of biosolids produced by earthworms exposed with the various applied concentrations of sodium hypochlorite are statistically similar (p<0.03)
77 with the results recorded in the control at 95% of confidence interval. Generally, the nutrient contents of biosolids produced by earthworms exposed to all the test chemical concentrations were similar with the control. This shows that the test chemicals did not affect the earthworms during nutrient mineralization process from blackwater after 21 days of exposure.
A similar trend on biosolids nutrient contents produced from blackwater have been reported by Sullivan et al., (2000), with total nitrogen (TN) ranging within 3-8%, total phosphorus (TP) 1.5-3% and potassium(K) 0.1-0.6%. All the nutrient contents (except total nitrogen) of biosolids fell within the ranges recorded in their study. The ranges of nutrients in the biosolids are varying from place to place and this may be due to factors such as, the quantity of organic matter, the duration (vermicomposting time) and the performance of earthworms during degradation process. Gnanaprakasam et al., (2013) from India documented a 21 days old blackwater vermicompost nutrient content. He obtained 1.8 % total nitrogen (TN), 1.7 % total phosphorus (TP) and 2% potassium (K).
2) E. coli Content
The earthworms were able to remove the pathogen contents of the blackwater by devouring of pathogens as food and by secretion of enzymes that can kill viruses and bacteria during biological degradation process of blackwater (Sinha et al ., 2009).The log removal of E. coli recorded by earthworms was not statistically similar (P=0.19) with gradual increase in applied concentration of chloroxylenol at 95% of confidence interval. This shows that the increment of applied concentrations did not cause any effect on earthworms in removing E. coli from the feed
(blackwater).
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The log removal was statistically similar (P=0.03) with gradual increase in applied concentrations at 95% confidence interval. This can be seen as the subsequent variation in applied concentrations caused different effects on earthworm potential in E. coli removal. The removal potential of earthworms recorded is not statistically similar (p=0.11) with gradual increment of applied concentrations of lactic acid (Mr. Muscle) at 95% of confidence interval.
The concentration variation did not cause effect on log removal potential of earthworms
(eudriluseugeniae ) in the removal of E. coli .
Generally, E. coli log removal efficiency achieved by earthworms exposed to all three test chemicals; chloroxylenol, sodium hypochlorite and lactic acid were similar with that of the removals by earthworms kept in the control. This implies that the applied concentrations of each test chemical did not influence earthworms on the removal of E. coli from blackwater.
3) Total Coliforms Content
The earthworms recovered from toxicity effect of the three test chemical concentrations were able to show an encouraging log removal of total coliforms from blackwater. Total coliforms of
2.2 and 4.6 log removal were achieved by the controls C 0 (blackwater without earthworms) and
C1 (blackwater with earthworms but without test chemicals) respectively. The various concentration of chloroxylenol caused similar effect on the efficiency of earthworms in total coliforms removal. Poor total coliforms log removal efficiency was observed by earthworms exposed to sodium hypochlorite (Mr. Muscle solution) tested at 1.3 mg/ml concentration. At
95% of confidence interval, the total coliforms log removals obtained by earthworms were not statistically similar (p=0.12) with the gradual increase in applied concentrations. This indicates that the effect of different concentrations of lactic acid (Mr.Muscle solution) did not cause
79 similar effects on the efficiency of earthworms in the removal of total coliforms from black water after 21 days of exposure.
The log removal efficiency achieved by earthworms exposed to all three test chemicals;
Chloroxylenol, sodium hypochlorite and lactic acid were statistically similar with that of the removals attained by earthworms kept in the control after 21 days of exposure.
4) Helminth Ova Content
Helminth ova or parasitic worms are normally retained in biosolids after solid-liquid separation from blackwater (Sullivan et al., 2000). The organic part of suspended solids in blackwater provide adsorption site for chemical and biological contaminants and hence they can be degraded biologically by macro and micro- organisms.
In the raw feed, relatively high concentration of helminthes parasites (725 HO/gTS) were recorded. The earthworms both in the control and test chemical treatments were able to reduce the concentration of Helminth ova present in black water.
The Helminth ova removal achieved after 21 days of exposure is statistically (p=0.02) similar with increase in applied concentrations at 95% of confidence interval. This shows that the presence of helminth ova in biosolid increased when the applied concentration of chloroxylenol increased. The toxicity effect was high with increased concentration so earthworms were not able to reduce the Helminth ova present in blackwater. In addition, the correlation test showed that the presence of helminth ova in the biosolid was positively correlated (0.997) with gradual increase in applied concentrations.The helminth ova concentration was also positively correlated with increase in applied concentrations of sodium hypochlorite which suggested that the gradual increase of applied concentration created an adverse effect on earthworm potential in order not to
80 remove helminth ova after 21 days of exposure. The presence of Helminth ova in biosolids was also indicated positive correlation (0.9) with gradual increase in applied concentrations of lactic acid after 21 days of exposure. The toxicity of lactic acid at higher concentrations affected the potential of earthworms’ removal of Helminth ova from the biosolids.
The study seeks to suggest that, earthworms were able to remove pathogens present in feed and/or biosolids and this may be due to the release of coelomic fluids which have antibacterial properties which can kill some of the pathogens (Pierre et al ., 1982). Removal of pathogens by earthworms could also have occurred by grazing of earthworms on ineffective microbes in the blackwater selectively and maintaining the effective biodegrading microbes to function well (Sinha et al., 2007). Even though Helminth ova removal was observed by earthworms, it could not meet the standards set by WHO for biosolid and faecal sludge application for agriculture which is recommended as ≤ 1 HO/g TS (WHO, 2006). Therefore because of the health risks of Helminth ova in biosolids, further treatment of biosolids would be required before applying it to agriculture.
4) COD Content
Earthworms are versatile waste eaters and decomposers and can ingest and remove several organic substances from wastewater which otherwise cannot be oxidized by microbes and thus bring down the COD values significantly (Sinha et al., 2009). Earthworms have been reported to remove over 90% of COD from municipal wastewater in vermifiltration processes (Tomar and
Suthar 2011; Sinha et al., 2007).
The removal of COD decreased with gradual increase of applied concentration. The effect of toxicity on earthworms increased as the concentration of chloroxylenol increased and so
81 earthworms were not able to remove the degradable COD content in blackwater, consequently, lower removal of COD recorded as compared to the control without earthworms (C 0). As the exposure time increased from 7 days to 14 days, the COD removal efficiency of earthworms also increased implying that the toxicity effect of chloroxylenol decreased and the earthworms started digesting the blackwater gradually.
Earthworms were highly affected by the toxicity effect of sodium hypochlorite during the first 7 days of exposure. The study also suggested that there was less toxicity effect on earthworms after 14 days exposure so earthworms were able to digest the blackwater and remove the COD significantly in comparison to the 7 days of exposure. Besides this, the correlation test indicates that COD removal obtained during the 14 days exposure was with lower correlation (-
0.996) with increase in applied concentrations than the removals obtained during the 7 days exposure (-0.999). It can be said that after 21 days of exposure low COD removal efficiency
(55%) was attained by earthworms exposed to sodium hypochlorite whilst encouraging removal efficiency (86%) was achieved by earthworms exposed to lactic acid.
5) COD Content
Removal of BOD by earthworms was high in the control test. It has been reported that 81% of
BOD reduction can be achieved in a control without earthworms in vermifiltration treatment of sewage sludge over a period of 10 hours (Sinha et al .,2009) . BOD reduction by 89% has been recorded by Ghatnekar et al ., (2008) for vermifiltration based treatment of municipal wastewater .
Mostly, earthworms degrade the blackwater organics by enzymatic action (that works as biological catalysts bringing pace and rapidity in biochemical reactions) and that may be the reason why high BOD removal was observed compared to COD removal (Sinha et al., 2007).
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Initial chemical spiking drastically reduced the efficiency of contaminant removal. This indicates that the more doses of chemicals added to earthworms caused more toxicity effect and thus less efficiency of BOD removal was observed after 7 days of experiment .
The study also suggested that as the duration of exposure is increased the toxicity effect on earthworms is decreased and the performance of earthworms digesting the blackwater is increased. The BOD removals recorded after 14 days of exposure were not statistically significant (T-test=0.06) with the removals recorded after 7 days of exposure at 95% of confidence interval. Generally, the BOD removal potential by earthworms decreased with increase in applied concentrations .
6) TDS Content
At 95% of confidence interval, the TDS removals recorded were statistically significant (p=0.003) with the gradual increase of chloroxylenol. Earthworms over the 14 days of exposure showed a better performance compared to the 7 days of removal but with low performance compared to the removals obtained in the controls (C 0) and (C 1).Up to 99% TDS removal have been reported by researchers such as Tomar and Suthar, (2011) and Kumar, et al ., (2013) from vermifiltration of municipal wastewater.
From the results, it can be deduced that high TDS removal potential of earthworms could be obtained with the minimum concentration of chloroxylenol. The removal efficiency of earthworms recorded after 21 days of exposure were also statistically significant (T-test, p=0.004). This shows that an increase in the exposure time reduces the toxicity effect of chloroxylenol for instance on the performance of earthworms; thus an increased adaptability to the environment and enhanced breakdown of contaminants.
Similarly, earthworms exposed to lactic acid were able to remove the TDS from blackwater reasonably after recovery. The applied concentrations used in the toxicity test also affected the TDS removal efficiency of earthworms with variation of exposure time. The study seeks to
83 suggest that TDS removal efficiency increased with exposure time when spiked with the various test chemicals.
7) TSS Content
Total Suspended Solids (TSS) removal was observed by both the control tests (C 0) without earthworms and (C 1) with earthworms Sinha et al., (2007) attained 99.98% TSS removal with earthworms in vermifiltration of municipal wastewater and 99.7% removal without the addition of earthworms in his control.
However, the study suggests that the removal potential of earthworms decreased due to the toxicity effect of the chemicals with gradual increase in applied concentrations however.
Notwithstanding, increase of exposure time relatively improved the removal efficiency. This shows that better TSS removal can be attained by earthworms with long exposure time. The TSS removals recorded over the 14 days of exposure were not statistically (T-test, P=0.07) similar with that of the removals obtained over the 7 days of exposure time. This implies that the increase of applied concentrations caused toxicty effect on earthworms and resulted in low removal efficency.
In conclusion, after the 7 days of exposure, earthworms were not able to remove all the contaminants (COD, BOD TDS and TSS) better than the removals attained by bacteria and other micro-organisms in the control (C 0). This agreed with body weight loss observed over the 7 days of exposure after treatment done by all the three test chemicals as discussed in earlier sections.
The result obtained showed that earthworms were able to recover from the toxicity effect of the three test chemicals after 14 days of exposure time with significant body weight growth and contaminant removal potential compared to the control.
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Earthworms can remove contaminants mainly COD, BOD TDS and TSS from blackwater by a general means of ‘Ingestion’(feeding) and biodegradation processes (Sinha et al., 2007). The earthworms in wastewater treatment processes such as the use of vermifiltration, were capable of transforming insoluble organic material to soluble form and then selectively digesting the sludge particles into finer state which facilitate further degradation of organic materials by bacteria and other micro-organisms in the system (Sudhir and Ghatnekar, 2010).
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CHAPTER FIVE
5.0. CONCLUSIONS AND RECOMMENDATIONS
5.1. CONCLUSION
This chapter draws together the main findings from this study in order to answer the three research questions stated below about the robustness of the Biofil Technology to bactericidal chemical constituents in black water:
V Are earthworms resistant to strong antiseptics and other toxicants such as, chloroxylenol
(dettol solution), sodium hypochlorite (parazone solution) or lactic acid (Mr. Muscle
solution)?
V What level of contaminant concentration (i.e. Lethal concentrations) will render the
system ineffective for decomposition and breakdown of organic constituents in black
water?
V What is the recovery rate of the system after bactericidal chemical contamination to the
decomposition and breakdown of organic constituents in black water?
After 21 days of exposure, this study concludes that chloroxylenol (Dettol) which is the most abundant antiseptic in several households was not able to kill 100% of the test organisms
(eudrilus eugeniae ) for the concentrations tested. The various applied concentrations of chloroxylenol (dettol) caused up to 62.5%, 50%, 37.5% 37.5% and 25% survival of earthworms tested by 0.3 mg/ml, 0.6mg/ml 1.2 mg/ml, 2.4 mg/ml and 5 mg/ml concentrations respectively.
The earthworms were not able to resist the toxicity effect of various concentrations of sodium hypochlorite (parazone) tested. More than 50% of the concentrations tested were able to cause
86
100% mortality effect on earthworms. The concentration, 2.5 mg/ml caused 100% mortality effect on earthworms which means that they were not able to resist toxicity at 2.5 mg/ml.
However, 62.5% and 50% of earthworms ( eudrilus eugeniae) were able to survive at concentrations of 0.6 mg/ml and 1.3 mg/ml respectively.
After testing with lactic acid (Mr.Muscle), 100% mortality was observed in the earthworms
(eudrilus eugeniae ) by a concentration of 7 mg/ml and up to 87.5% of the earthworms were able to survive with the minimum concentration tested (0.7mg/ml) in the biofil toilet technology blackwater flushing system.
The earthworms after toxicity effect of various concentrations of the three test chemicals were able to recover after the exposure of 14 days and onwards. This was assessed by the body weight change of earthworms with respect to their original body weight. Hence earthworms were able to increase their bodyweight by a maximum of 38.7% after 21 days of exposure. The earthworms exposed to lower concentrations of the three chemical were also able to remove pathogens such as E. coli , total coliforms and Helminth ova with log removals up to 4.5, 4.6 and 87% respectively. They also removed COD up to 86%, BOD up to 89% TDS 92% and TSS 94% from blackwater after recovered from the toxicity effect of the three test chemicals.
Finally, it was realised that higher concentrations of the chemicals resulted in lower removal of contaminants by the earthworms (eudrilus eugeniae ) and increase in exposure time gradually increased the removal of contaminants by the earthworms in the biofil toilet technology.
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5.2. RECOMMENDATION
For the BTT users employing sodium hypochlorite (parazone) as cleaning chemical can potentially affect the effectiveness of the technology, so it may be advisable to use this chemical with minimum dosages (less than 0.6 mg/ml) for cleaning of the bathrooms in the BTT while using chloroxylenol (dettol) will cause relatively less effect on the activity of earthworms to improve the robustness the biofil toilet technology.
For further study care has to be taken during the collection of blackwater to make sure that it was not already contaminated with other toxic cleaning chemicals before dosing the applied concentration for testing as it may affect the performance of earthworms.
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REFERENCES
Ali, A., 2002.Appropriate Environmental and Solid Waste Management and Technologies for Developing Countries. International Solid Waste Association, 1(12), pp. 17-25.
Adarsh Pal Vig, Jaswinder Singh,Shahid and H.Wani ., 2011. Vermicomposting of tannery sludge mixed with cattle dung into valuable manure using earthworm Eisenia fetida (Savigny). Bioresource technology , 102(17), pp.7941–5. Available at: http://www.ncbi.nlm.nih.gov/pubmed/21676611 [Accessed April 22, 2014].
Ansari and Ismail, 2012. Earthworms and Vermiculture Biotechnology,Management of Organic Waste D Journal of Biosciences , (88-94), pp.4–9. Available at: http://www.intechopen.com/books/management-of-organic-waste/earthworms-and-vermiculture- biotechnology.
Basheer M. and O.P.Agrawal ., 2013. Management of Paper Waste by Vermicomposting Using Epigeic Earthworm , Eudrilus eugeniae. International Jorunal of Current Microbiology and Applied Sciences , 2(4), pp.42–47. Available at: http://www.ijcmas.com.
Bassan, Tchonda, L. yiougo, H. Zoellig, I.Mahamane and L.S.M. Mbeguere., 2013. Delivering Water, Sanitation and Hygiene Services in an Uncertain Environment-Characterization of Faecal Sludge During Dry and Rainy Seasons in Ouagadougou, Burkina Faso. 36th WEDC international conference, kenya , 3(9), pp.1–7.
Bhattacharjee, G. and H.Chaudhuri, 2002. Cocoon production, morphology, hatching pattern and fecundity in seven tropical earthworm species - a laboratory-based investigation. Journal of biosciences , 27(3), pp.283–94. Available at: http://www.ncbi.nlm.nih.gov/pubmed/12089477.
Bjorn Vinnerås, 2001. Faecal separation and urine diversion for nutrient management of household biodegradable waste and wastewater. Journal of Biosciences , 5(2), pp.29–50.
Brouckaert, K.M.F.K. wood, 2012. Modelling the filling rate of pit latrines. Pollution Reaserch Group , 1(9), pp.4–12.
Buckley, C., 2011. What Happens When the Pit is Full ? Developments in On-Site Faecal Sludge Management(FSM). Water Research Commision and Water Information Network south Africa , (14- 15 March 2011), pp.8–42.
Charles B. Niwagaba, 2009. Treatment Technologies for Human Faeces and Urine . kampala: Makerere University.
Cornelis A.M. VanGestel, Josee E. Koo lhaas and Timo Hamers ., 1992. Effects of Metal Pollution on Earthworm Communities in a Contaminated floodplain area: Linking Biomarker, Community and Functional Responses. Environmental pollution (Barking, Essex : 1987) , 157(3), pp.895–903. Available at: http://www.ncbi.nlm.nih.gov/pubmed/19062144 [Accessed April 15, 2014].
Cox, M., 2008. Understanding Toxic Substances. Journal of Public Health , 3(5), pp.5–26. Available at: www.cdph.ca.gov/programs/hesis.
89
David J. Mattson S.P and L. Marilynn ., 2005. Consumption of Earthworms by Yellowstone Grizzly Bears. Journal of U.S. Geological Survey , 1(25), pp.2–5.
David J. Spurgeon ,Lindsey Lister , Peter Kille, M.gloria and Pereira Julian Wright ., 2011. Toxicokinetic studies reveal variability in earthworm pollutant handling. Pedobiologia-International Journal of Soil Biology , 54(6), pp.S217–S222. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0031405611000795 [Accessed April 12, 2014].
Deka H. , S. Deka, C.K. Baruah , J.Das ,S. Hoque and H. Sarma ., 2011. Bioresource Technology Vermicomposting potentiality of Perionyx excavatus for recycling of waste biomass of java citronella - An aromatic oil yielding plant. Bioresource Technology , 102(24), pp.11212–11217. Available at: http://dx.doi.org/10.1016/j.biortech.2011.09.102.
Dominguez and Edwards, 2011. Biology and Ecology of Earthworm Species Used for Vermicomposting. Taylor and Francis Group , 1(6), pp.3–12.
Dominguez, J. and M. Aira., 2011. Chapter 25 New Developments and Insights on Vermicomposting in Spain. Journal of Cleaner Production , 2(5), pp.409–421.
Drangert, J.O., 1998. Fighting the urine blindness to provide more sanitation options. Water south Africa , 24(2), pp.2–5.
Dvid J and S.P.H. Spurgeon ., 1995. Extrapolation of the Laboratory-Based OECD Earthworm Toxicity Test to Metal-Contaminated Field Sites. Ecotoxicology and Environmental safety , 4(24), pp.190– 205.
Efrymson and M.E Will., 1997. Toxicological Benchmarks for Contaminants of Potential Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process. Ecotoxicology and environmental safety , (November), pp.15–27.
EHCC, 2006. Household Chemicals. Children’s Environmental Health Network , 5(10), pp.2–11. Available at: www.cehn.org/ehcc.
Fidjel, 2010. Quantitative Microbial Risk Assessment of Agricultural Use of Fecal Matter Treated with Urea and Ash. Jornal of biological Sciences and microbial risks , pp.4–45.
Flores. R.F and C. Buckley ., 2009. Selecting sanitation systems for sustainability in developing countries. Water science and technology : a journal of the International Association on Water Pollution Research , 60(11), pp.2973–82. Available at: http://www.ncbi.nlm.nih.gov/pubmed/19934519 [Accessed April 23, 2014].
Flores.R.F and C.Buckley., 2008. Selecting Wastewater Systems for Sustainability in Developing Countries. 11th International Conference On Urban Drainage , 1(3), pp.2–8.
Franceys R. J. Pickford and R. Reed ., 1992. A Guide to the Development of On-Site Sanitation. World Health Organization , (ISBN 92 4 154443 0), pp.12–19.
Franceys R.J. Pickford. and R.Reed., 1992. Linking Technology Choice with Operation and Maintainanace. Sanitation Fact Sheet , 2(8), pp.103–128.
90
Frederic Leduc, Joann K and G.I.S. Whalen ., 2008. Growth and Reproduction of the Earthworm Eisenia fetida After Exposure to Leachate from Wood Preservatives. Ecotoxicology and Environmental Safety , 69(2), pp.219–26. Available at: http://www.ncbi.nlm.nih.gov/pubmed/17559932 [Accessed April 15, 2014].
Friendrike Wolfarth, Stefan Schrader, Elisabeth Oldenburg and Joachim Weinert ., 2011. Earthworms Promote the Reduction of Fusarium Biomass and Deoxynivalenol Content in Wheat Straw Under Field Conditions. Soil Biology and Biochemistry , 43(9), pp.1858–1865. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0038071711001957 [Accessed December 2, 2013].
Gajalakshmi. S. and Abbasi. S.A., 2004. Earthworms and Vermicomposting. Indian Jorunal of Biotechnology , 3(october 2004), pp.486–494.
Ghatnekar, S.D., Ghalsla-Dighe D.S.and S.S. Ghatnekar., 2008. Zero Discharge of Wastewater from Juice Making Industry Using - Bio-Filtration Technology. 6th European Wastewater Management Conference and Exhibition , 6, pp.3–8. Available at: www.ewwmconference.com.
Gnanaprakasam A., Kannadasan T., Mnoj Presath and K.V.S.Ashif ., 2013. Production of Organic Fertilizer by Vermi-Composting Method. Research Jorunal of Chemical Sciences , 3(5)(May(2013)), pp.89–92. Available at: www.isca.in.
Grdiša, M. and K.M.G. Grši ., 2013. Minireview on Earthworms-Role in soil Fertility to the Use in Medicine and as Food. International scientific journals , 2(4), pp.38–45.
Gross, 1978. Assesment of the effects of household chemicals upon individual septic tank performances. water resource research center , 1(3), pp.2–26.
Gunawardana I.P.P and L.W.Galagedara ., 2011. Practical Issues of Partial Onsite Sanitation Systems : Two Case Studies from Sri Lanka. Tropical Agricultural Research , 22(2)(2), pp.144–153.
Heather, Esper, and Y.K. Ted London ., 2013. Improved Sanitation and Its Impact on Children : An Exploration of Sanergy. Child Impact Case study No 2 William Davidson Institute , 1(5), pp.7–42.
Heinss, U. and M. Strauss., 1999. Co-treatment of Faecal Sludge and Wastewater in Tropical Climates. , (January).
Heron, A.H., 2005. Low-cost sanitation: An Overview of Available Methods. Water Research Group , (3), pp.59–69.
Ingallinella, A.M Sanguinetti, G. and T.Koottatep ., 2002. The challenge of faecal sludge management in urban areas--strategies, regulations and treatment options. Journal of the International Association on Water Pollution Research , 46(10), pp.285–94. Available at: http://www.ncbi.nlm.nih.gov/pubmed/12479483.
Ignatius Ip and E.Craig Jowett ., 2004. The effect of Household Chemicals on septic tank performance. presented at the 2004 ASAE conference , 2-14, pp.2–14.
91
Ismail and S.Ansary., 2005. Soil Health Is Human Health- An Indian Earthworm’s Review. Indian Journal of Biotechnology , 1(6), pp.61–108.
Jilani, 2007. Municipal Solid Waste Composting and Its Assesment for Reuse in Plant Production. Jornal of Environmental Science and Technology , 39(1st July), pp.271–277.
Jimenez-Cisneros, 2008. Healminth Ova Control in Wastewater and Sludge for Agricultural Reuse. Water and Health [Ed.w.o.k.Grabow],Encyclopedia of Life support systems , 1(9), pp.5–13. Available at: http://www.eolss.net.
John J. Schwartz, Ann T. and K.P. Lemley ., 2004. Household Chemicals and Your Septic System. USer Guide Manual and Fact Sheet , 1(16), pp.3–4.
Jorge Dominguez and Edwards., 2004. vermicoposting of organic wastes. soil zoology For Sustanable Development in the 21st centuary. , 2(8), pp.2–5.
Joshi, N. and M. Dabral ., 2008. Life Cycle of Earthworms Drawida nepalensis , Metaphire houlleti and Perionyx excavatus Under Laboratory Controlled Conditions. Life Science Journal , 1(20), pp.83–86.
Kirsten Wood, 2013. Transformation of Faecal Sludge in VIPs:Modellin Filling rate with an Unsteady- State Mass Balance . University of KwaZulu-Natal.
Kratzer, 2003. Safe Use and Disposal of Household Chemicals. Journal of Resource Management , 2(11), pp.1–2.
Kuffour, E. Awuah, N. Adamtey and F.O.K.Anymedu ., 2013. Agricultural Potential of Biosolids Generated from Dewatering of Faecal Sludge on Unplanted Filter Beds . Civil and Environmental Research , 3(5), pp.10–18. Available at: www.ijste.org.
Kwashie, 2009. Microbial Analysis of Soil Samples In a Wastewater Irrigated Vegetable Production Site: Case study at Atonsu,Kumasi. Biology and Fertility of Soils , 5(3), pp.9–29.
Lakshmi, R.S., 2012. A Review of Vermifiltration and Related Low Cost Alternatives for Wastewater Management. 16-Evh-Rohit Pathania , 2(3), pp.1–7.
Landrum, M., Cañas, J.E. and Coimbatore, 2006. Effects of perchlorate on earthworm (Eisenia fetida) survival and reproductive success. The Science of the Total Environment , 363(1-3), pp.237–44. Available at: http://www.ncbi.nlm.nih.gov/pubmed/16005494 [Accessed July 7, 2014].
Latifah Abd Manaf, Mohd Lokman Che Jusoh, Mohd Kamil, Yusof Tengku Hanidza, Tengku Ismail and H.J.Rosta Harun ., 2009. Influences of Bedding Material in Vermicomposting Process. International Journal of Biology , 1(1), pp.81–91. Available at: www.ccsenet.org/jornal.html.
Mainoo, 2007. Feasibility of Low Cost Vermicompost Production in Accra,Ghana . McGill University.
Martin Strauss, 2000. Human Waste ( Excreta and Wastewater ) Reuse. EAWAG/SANDEC- Water and Sanitation in Developing Countries , (1), pp.1–31.
92
Meiyan Xing, Jian Yang, Yyi Wang and F.Y. JingLiu ., 2011. A Comparative Study of Synchronous Treatment of Sewage and Sludge by two Vermifiltrations Using an Epigeic Earthworm Eisenia fetida. Journal of hazardous materials , 185(2-3), pp.3–4. Available at: http://www.ncbi.nlm.nih.gov/pubmed/21041027 [Accessed April 22, 2014].
Mulenga, 2011. urban sanitation path finder. sanitation and Hygiene Applied Research for Equality SHARE,London , pp.1–44.
Norbu, T., 2002. Pretreatment of Municipal Solid Wate by Windrow Composting and Vermicomposting. Journal of Environmental Biology / Academy of Environmental Biology, India , 3(6), pp.39–125.
Owojori, A.J. Reinecke and P. Voua-Otomo ., 2009. Comparative Study of the Effects of Salinity on Life-Cycle Parameters of Four Soil-Dwelling Species (Folsomia candida, Enchytraeus doerjesi, Eisenia fetida and Aporrectodea caliginosa). Pedobiologia , 52(6), pp.351–360. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0031405609000031 [Accessed October 15, 2013].
OECD, 1984. “Earthworm, Acute Toxicity Tests.” OECD Guidelin for Testing of Chemicals , 207(4), pp.2–8.
OSHC, 2003. Guide lines for the common use of chemical disinfectants. occupational safety and health council .
Otitoloju, A.A., 2005. contaminated ecosystem. Journal of Life and Physical stress , 2(27), pp.1–5. Available at: www.actasatech.com.
Petterson, S.A. and N.J. Ashbolt ., 2006. WHO Guidelines for the Safe Use of Wastewater and Excreta in Agriculture Microbial Risk Assessment Section. World Health Organization , 3(1), pp.2–36.
Prakash Mallappa Munnoli Jaime A, Teixeira da and Silva Saroj Bhosle ., 2010. Dynamics of the Soil- Earthworm-Plant Relationship Review. Global Science Books , 5(29), pp.5–14.
Prasad, B.A., 2013. Urban Sanitation : Health Challenges of the Urban Poor. Family, Community and Consummer Sciences , 1(10), pp.1–6. Available at: www.isca.in.
Priyanka Tomar and Surindra Suthar, 2011. Urban wastewater Treatment Using Vermi-Bio Filtration System. Journal of Desalination , 282(1), pp.95–103. Available at: http://dx.doi.org/10.1016/j.desal.2011.09.007.
Rahul Kumar, S., 2011. Removal of Pathogens During Vermi-Stablization. Jornal of Environmental Science and Technology , 2, pp.1–5.
Rajiv K. Sinha, Sunil Herat and Gkul Bharambe ., 2009. Vermistabilization of Sewage Sludge ( biosolids ) by Earthworms : Converting a Potential Biohazard Destined for Landfill Disposal into a Pathogen-Free , Nutritive and Safe Biofertilizer for Farms. Waste Management and Research , 3(31), pp.3–7. Available at: http://wmr.sagepub.com.
Robyn Dunmore and G.H. Richard Piola ., 2011. Assessment of the Effects of Household Cleaners for the Treatment of Marine Pests. Journal of Biosecurity , 5(January), pp.21–22. Available at: www.biosecurity.govt.nz/about-us/our-publications/technical-papers.
93
Seetha Devi, G, Karthiga and A, Susila ., 2012. Bioconversion of Fruit waste into Vermicompost by Employing Eudrilus eugeniae and Eisenia fotida. International Journal of Plant,Animal and Environmental Sciences , 2(4), pp.4–5. Available at: www.ijpaces.com.
Seleman, A., 2012. Assessing Sustainability of Sanitation Technologies Recommended for Rural Settings : A Case Study of Morogoro District , Tanzania. FIU Electronic Theses nd Disertations paper 690 , 1(3), pp.23–59.
Sherman R., 2003. Raising Earthworms Successfully. International jornal of biology , pp.5–24.
Sinha, R.K., 2009. Vermiculture and Sustainable Agriculture S. American-European Jornal of Agriculture and Environmental science , pp.2–29.
Sinha.G and P.B. Bharambe ., 2007. Removal of High BOD and COD Loadings of Primary Liquid Waste products From Diary Industry by Vermi-Filtration Technology Using Earthworms. International Journal of Environmental protection , 6(14), pp.486–501.
Sivasankari.B and S.A.Indumathi ., 2013. A Study on Life Cycle of Earth worm Eudrilus eugeniae. International Jornal of Research in Pharmacy and Life Science , 1(2), pp.64–67. Available at: www.pharmaresearchlibrary.com/ijrpls.
Stephen Baker, 2002. Earthworms and Casting Control in the United Kingdom. Rutgers center for Turfgrass Science and Agricultural Experiment Station , 34(10), pp.3–4.
Van Straalen ., 1998. Ecological Risk Assesment of Soil Fauna Recovery from Pesticide Application. Journal of Environmental Toxicology. , 2(9), pp.5–28.
Strauss, W.C. Narrero, M.steiner, A. Mensah, M.Jeuland S. and A.M.D.K.Bolomey. , 2003. Urban excreta management - situation, challenges, and promising solutions. SANDEC , 2, pp.3–9.
Sudhir D. Ghatnekar., 2010. Application of Vermi-filter-based Effluent Treatment Plant ( Pilot scale ) for Biomanagement of Liquid Effluents from the Gelatine Industry. Global Science Books , 2(September,2010), pp.2–6.
Sullivan, M. Granatstein Craig G. Cogger, Charles L and K. p. D. Henry., 2000. Biosolids Management Guidelines for Washington State. Journal of Environmental Science and Technology , 5(2), pp.4– 233. Available at: [email protected].
Tidåker, P., Mattsson, B. and Jönsson ., 2007. Environmental Impact of Wheat Production Using Human Urine and Mineral Fertilisers – a Scenario study. Journal of Cleaner Production , 15(1), pp.52–62. Available at: http://linkinghub.elsevier.com/retrieve/pii/S0959652605001642 [Accessed June 6, 2014].
Trondel, B., 2010. Sanitation Ventures Literature Review : on-site sanitation waste characteristics. London School of Hygiene and Tropical Medicine , 4(1), pp.1–30.
VanGestel C.M and W, A.Van Dis., 1988. The influence of soil characteristics on the toxicity of four chemicals to the earthworm Eisenia fetida andrei (Oligochaeta). Biology and Fertility of Soils , 6(3), pp.3–4. Available at: http://link.springer.com/10.1007/BF00260822.
94
Wendland, C., 2008. Anerobic Digestion of Blackwater and Kitchen Refuse Anaerobic Digestion of Blackwater G. zur F. and Entwicklung, ed. Journal of biosciences , 12(3), pp.22–125. Available at: http://www.gfeu.org.
WHO/UNICEF, 2013. progress on sanitation and drinking water. world health organization and Unifef joint monitoring programme report , 1(12-34), pp.4–40.
WHO/UNICEF, 2010. Progress On Sanitation and Drinking Water. WHO/UNICEF joint programe for watersupply and sanitation , 2(1), pp.10–39. Available at: www.paprika.annecy.com.
Yuansong Wei, Renze T. Van Houten, Arjan R.Borger, Dick H. and Y.F. Eikelboom ., 2003. Minimization of Excess Sludge Production for Biological Wastewater Treatment. Water rRsearch , 37(18), pp.4453–67. Available at: http://www.ncbi.nlm.nih.gov/pubmed/14511716 [Accessed March 21, 2014].
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INTERNET SOURCES
Biofilcom (Biological Filters and Composters); accessed on October, 08, 2013. http://www.biofilcom.com/pages/the-biofil-toilet-system.php
The household chemical fact sheet paper (chloroxylenol (dettol)) last accessed November, 2013
(http://www.gpo.gov/fdsys/pkg/FR-2013-12-17/pdf/2013-29814.pdf ) http://www.rbnainfo.com/MSDS/US/Dettol-US-English.p
Sodium hypochlorite users guide line and fact sheet, last accessed 12, th December 2013.
(http://www.aadvark.co.uk/products/MSDS/561900%20Parozone%20Toilet%20Cleaning%20Wipes%20 40%20Sheets_JP_SDSP-3.pdf ). http://www.mexichem.com/English/docs/hojas_seguridad/MSDS_SODIUM_HYPOCHLORITE_COAT ZA.pdf
Safety and Effectiveness of Consumer Antiseptics(2013).Topical Antimicrobial Drug Products for Over-the-Counter Human Use; Proposed Amendment of the Tentative Final Monograph; Reopening of Administrative Record; Proposed Rule ( http://www.gpo.gov/fdsys/pkg/FR-2013- 12-17/pdf/2013-29814.pdf
The pour flush latrines Fact Sheet 3.6, sanitation in emergency areas. http://www.who.int/water_sanitation_health/hygiene/emergencies/fs3_6.pdf
Earthworms life cycle-cocoon production, last accessed June, 2014 . http://www.learner.org/jnorth/search/WormNotes2.html
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APPENDICES
Table A-1: Earthworms Survival Potential after Exposure of Various concentrations of Chloroxylenol (dettol).Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 Days of Exposure
Type of test chemical used concentration(mg/ml) 7 Days 14 Days 21 Days Control 0 8 8 8 0.3 8 6 6 Chloroxylenol 0.6 7 5 5 (dettol solution) 1.2 4 3 3 2.4 3 2 2 5 2 2 2 0.6 7 5 5 1.3 6 4 4 Sodium hypochlorite 2.5 0 * * (parazone solution) 5 0 * * 9 0 * * 0.7 7 7 7 Lactic acid 1.3 7 6 6 (Mr.Muscle solution) 2.4 6 5 5 4 3 2 2 7 0 * *
N.B * =No data collected on earthworms over the 14 and 21 days of exposure due to 100% mortality effect after 7 days.
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Table A-2: Body Weight Change of Earthworms Exposed to Chloroxylenol (dettol), Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 days of exposure
Type of test chemical concentration Initial (0 Day) 7 Days of 14 Days of 21 Days of Body (mg/ml) Body weight(g) Body weight(g) weight(g) Body weight(g)
Control(C 1) 0 514 628 852 1252 0.3 484 445 598 830 Chloroxylenol 0.6 566 527 685 942 (dettol solution) 1.2 566 507 652 885 2.4 507 425 520 683 5 566 421 511 670 0.6 521 440 517 632 Sodium hypochlorite 1.3 670 479 554 671 (parazone solution) 2.5 521 * * * 5 608 * * * 9 458 * * * 0.7 434 433 561 739 Lactic acid 1.3 656 649 767 982 (Mr.Muscle solution) 2.4 685 672 786 967 4 626 589 613 715 7 645 * * *
N.B * =No data collected on earthworms over the 14 and 21 days of exposure due to 100% mortality effect after 7 days.
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Table A-3: Characteristics and Nutrient Contents of Biosolids Produced by Earthworms Exposed to Chloroxylenol (dettol), Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 Days of Exposure.
Tp K TC type of test chemical concentration Temperature PH TN (%) (%) (%) (%) used (mg/ml) ℃ Control(C1) 0 30.9 7.9 2.6 1.7 0.4 23.0 Chloroxylenol 0.3 31.5 7.9 2.5 0.3 0.3 22.8 (dettol) 1.2 32.4 8.1 2.5 1.4 0.4 25.8 0.5 31.3 8.0 2.4 1.2 0.3 28.0 Sodium hypochlorite 0.6 31.4 8.0 2.4 1.5 0.5 26.3 ( parazone) 1.3 31.9 7.9 2.7 1.3 0.5 26.4 2.5 * * * * * * 0.7 32.1 7.9 2.2 1.2 0.2 25.4 Lactic acid 2.4 32.3 7.9 2.1 1.1 0.2 29.1 (Mr.Muscle) 4 30.5 7.9 2.2 1.3 0.2 27.0
*=The missing data due to the death of earthworms after 7 days of exposure
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Table A-4: Pathogen Contents in the Biosolids Produced by Earthworms Exposed to Chloroxylenol (dettol), Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 Days of Exposure.
Helminth ova(HO/g concentration E. coli(FCU/100ml) Total coliforms(CFU/100ml) TS) Type of chemical (mg/ml) used 7 days 14 days 21 days 7 days 14 days 21 days 7 days 14 days 21 days control(C 0)without earthworms 0 2.00E+09 1.10E+09 1.10E+09 2.90E+09 1.70E+09 2.30E+07 712 697 689 control(C 1) with earthworms 0 1.00E+07 5.00E+06 5.00E+06 2.30E+07 7.00E+06 1.00E+05 75 72 61 0.3 1.20E+07 7.00E+06 7.00E+04 2.70E+07 1.60E+07 9.00E+04 298 165 142 Chloroxylenol 1.2 1.40E+07 8.00E+06 9.00E+04 3.00E+07 2.00E+07 2.00E+05 308 197 160 (dettol solution) 5 1.60E+07 1.00E+07 1.10E+05 3.50E+07 2.50E+07 2.80E+05 489 382 308 Sodium hypochlorite 0.6 1.30E+07 6.00E+06 7.00E+05 2.40E+07 1.30E+07 7.00E+04 125 97 95 (parazone solution) 1.3 1.30E+07 1.50E+07 1.10E+05 2.40E+07 1.80E+07 1.20E+05 605 575 428 2.5 * * * * * * * * * 0.7 1.10E+07 6.00E+06 9.00E+04 3.00E+07 9.00E+06 1.70E+05 189 153 123 Lactic acid 2.4 1.50E+07 7.00E+06 1.00E+05 3.10E+07 1.30E+07 2.40E+05 211 175 145 (Mr.Muscle) 4 1.20E+09 7.00E+06 1.30E+05 2.20E+09 2.20E+07 2.80E+05 379 376 350
*=The missing data due to the death of earthworms after 7 days of exposure
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Table A-5: COD, BOD, TDS and TSS Contents in the Biosolids Produced by Earthworms Exposed to Chloroxylenol (dettol), Sodium hypochlorite (parazone) and Lactic acid (Mr.Muscle) over the 21 Days of Exposure. type of chemicals used concentration COD(mg/l) BOD(mg/l) TDS(mg/l) TSS(mg/l) 21 7 14 21 14 21 mg/l 7 days 14 days days days days days 7 days days days 7 days 14 days 21 days control(C 0)without earthworms 0 1241 1072 1000 300 294 271 1489 893 886 2104 1928 1511 control(C 1) with earthworms 0 358 261 254 122 115 96 312 300 289 525 514 452 0.3 684 354 289 253 136 95 1205 604 298 1789 871 478 Chloroxylenol 1.2 872 421 318 382 152 105 1329 795 452 2138 912 649 (dettol solution) 5 1023 579 405 490 206 149 1512 978 608 2290 1109 763 Sodium hypochlorite 0.6 912 500 450 383 182 152 1423 623 486 2093 935 645 (parazone solution) 1.3 1274 907 814 551 241 198 1680 895 649 2598 1009 789 2.5 * * * * * * * * * * * * 0.7 673 298 251 258 132 97 1352 890 605 1892 524 353 Lactic acid 2.4 806 400 324 325 145 78 1493 998 728 2178 800 621 (Mr.Muscle) 4 916 471 368 418 163 80 1603 1120 931 2205 885 657
*=The missing data due to the death of earthworms after 7 days of exposure
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Figure B-1 Some Pictures during Laboratory Experimentation
A B
Various concentrations of test chemicals (A) Experimental set up with the feed (B)
D C
A picture during sampling of the parameters (C) The internal view of the vermibed with earthworms (D)
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