Sustainable Wastewater Management in Buildings

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POLITECNICO DI MILANO

Scuola di Ingegneria Civile, Ambientale e Territoriale - MI Laurea Magistrale INGEGNERIA PER L’AMBIENTE E IL TERRITORIO - ENVIRONMENTAL AND LAND PLANNING ENGINEERING

Supervisor: Dr. Manuela Antonelli,Ph.D. Assistant Supervisor: Eng. Riccardo Delli Compagni

Submitted by: Awaz Alfadil Alkhalifa Mohamed 835755 Academic year 2016/2017 Contents

List of Tables 10

List of Figures 12

Nomenclature 13

1 Municipal wastewater 2 1.1 Introduction ...... 2 1.2 Water Consumption ...... 3 1.3 Wastewater Flows ...... 4 1.4 Residential wastewater ﬂow division ...... 5 1.5 Municipal Wastewater Characterization ...... 7 1.6 Indoor wastewater ...... 11 1.7 Outdoor wastewater ...... 16 1.8 Rainwater Harvesting ...... 17 1.9 Wastewater in Developing Countries ...... 20 1.10 Compliance to Legislations ...... 21

2 Sustainable treatment Technologies 24 2.1 Introduction ...... 24 2.2 Choice of Technology ...... 24 2.3 Overview of current treatment Technologies ...... 26 2.3.1 Treatment and Disposal: ...... 28

3 Living Machines 30 3.1 Introduction ...... 30 3.2 Successful Installments of LM ...... 32 3.3 Operating principles ...... 33

2 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings 3.3.1 Functionality of a LM ...... 33 3.3.2 Maintenance of LM ...... 35 3.4 Driving Factors ...... 35 3.5 System Design ...... 41 3.6 Advantages of LMs ...... 43 3.7 Restrictions and Challenges: ...... 43 3.8 Maintenance: ...... 44

4 Wastewater treatment using microbial fuel cells MFCs 46 4.1 Introduction ...... 46 4.2 Progression and evolution: ...... 47 4.3 MFCs Design ...... 48 4.4 MFC Operation ...... 54 4.5 Factors Aﬀecting MFC performance ...... 56 4.6 Beneﬁts of using MFCs: ...... 59

5 Sewage Treatment by Vermifiltration and Earthworms’ sludge digestion 62 5.1 Introduction ...... 62 5.2 Characteristics of Earthworms ...... 63 5.3 Critical factors influencing sewage vermifiltration ...... 65 5.4 The advantages of vermifiltration technology over conventional wastewater treatment systems ...... 67

6 Analysis: Case studies 72 6.1 Introduction ...... 72 6.2 Water’ Streams Division ...... 73 6.3 Vermiﬁltration ...... 81 6.4 MFC system ...... 87 6.5 Recommendations for the future:UV disinfection ...... 95 6.6 Conclusion ...... 98

Appendices 99 .1 Appendix ...... 100

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Bibliography 102

Page 4 Nomenclature

ηact,c activation polarization losses on cathode

ηact,a activation polarization losses on anode

φ Soil Porosity.

ϕ Roof runoﬀ coeﬃcient

$ roof runoﬀ coeﬃcient

A Area of the Roof in m2

A Roof surface area in m2

A the contact area in the soil proﬁle in m2.

Au Gold

Au Silver

BOD5 5 days Biological Oxygen Demand in mg/l.

BOD5 Biological Oxygen Demand in mg/l.

BOD5 Biological Oxygen Demand

Ca Calcium.

Cd Cadmium.

COD Chemical Oxygen Demand in mg/l.

Cr Chromium

Cu Copper.

5 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

DO Dissolved Oxygen

Ecell cell potential at T

ET Evapotranspiration

F Faraday Constant ftimefraction time that users stay in the analysed premise ftimefraction time that users stay in the analysed premise

F e Iron.

F e3+ Iron g/inhab.d gram per inhabitant per day g/m3 gram per cubic meter gpcd Gallon/capita/day

Hg Mercury.

I Daily volume of collectable rainwater in L

I Daily volume of the collectable rainwater

I Electrical Current in Amperes i current ﬂowing through the MFC

K Potassium kA kilo Ampere kg/yr Kilogram per year kL kilo Liter kW h Kilowatt per hour, measurement of the electrical energy

Page 6 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings kW h Kilowatt per hour kW h/day Kilowatt hour per day

LP low pressure

LP HO low pressure high output mA milli Ampere mg/l milligram per liter mg/m3 milligram per cubic meter

Mn manganese.

MnO2 Manganese dioxide

MP medium pressure

N Nitrogen

Nusers Number of users/residents

NH4 Ammonia

NO3 Nitrates

O the daily nonpotable water withdrawal from the tank

P Phosphorous purine Urine production per day

Pel Electrical power in Watts purine Urine production per day

P b Lead.

P t Platinum

Q wastewater ﬂow rate in l/sec.

Qr reaction quotient

R Daily rainfall depth in mm

R Universal gas constant

Ri internal cell resistance

T Temperature in kelvins t day number t the day number t the time taken by the wastewater to pass through the soil proﬁle. tstorage time of storage

TDS Total Dissolved Solids in mg/l.

TSS Total Suspended Solids in mg/l.

V Voltage in Volts

V/day Volt per day

Vs volume of soil proﬁle through which the water passes and is inhabited with the earthworms in m3.

Vt Water Volume in the tank

Vt water volume in the tank

Vcell Cell voltage

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Voc open circuit Voltage

Vstorage Storage Volume

Vwastewater The volumetric ﬂow rate of the wastewater.

VFA Volatile Fatty Acids.

V ol Volume z the number of moles of electrons transferred in the cell reaction

Zn Zinc.

θ E cell Standard cell potential

... ..

Page 9 List of Tables

1.1 per capita water consumption rates [1] ...... 3 1.2 Wastewater Rates for Residential establishments [2] [3] . . . .5 1.3 water use for household devices [4] [5] [6] ...... 6 1.6 Contamination measures and their degree of biodegradation in g/m3 [1]...... 8 1.4 Domestic wastewater consistuents [7] ...... 9 1.5 Main and mutual wastewater components in g/m3 [1] . . . . . 10 1.7 Metallic contamination values in residential wastewater in mg/m3 .Source [8], [7] and [9]...... 11 1.8 Annual amount of main domestic wastewater components [10] 11 1.9 Reduction with Urine Separation and Cleantech cooking in g/m3 [11]...... 12 1.10 Characteristics of grey and black wastewater [12]...... 13 1.11 Composition and Quantities of Urine and Human Faeces in urban wastewater [13]...... 13 1.12 Water consumption in developing regions ...... 21 1.13 Investigation and measurment characteristics of wastewater in Developing Countries [14] [1] ...... 22

3.1 Final removal limits in LM ...... 43

4.1 MFC Components [15] ...... 49 4.2 Electrode reactions and corresponding redox potentials . . . . 55

5.1 Vermiﬁlter, Source:Vermiﬁltration systems for liquid waste management: a review [16] ...... 67 5.2 Municipal wastewater characteristics [17] ...... 71

10 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

6.1 Composition of untreated domestic wastewater [18] ...... 73 6.2 Building characteristics [19] [20] ...... 73 6.3 Data about the urination [21] [22] ...... 74 6.4 calculation of urination and its water consumption ...... 74 6.5 Data about the defecation [23] ...... 75 6.6 Rainfall Estimation ...... 76 6.7 Outdoor water Estimation [19] ...... 76 6.8 Grey water Estimation [21] ...... 77 6.9 Grey water characteristics [24] [25] ...... 77 6.10 Final Effluent from LM adopted from (Living Machines, Inc., 2001)...... 78 6.12 Vermifilter, Source:Vermifiltration systems for liquid waste management: a review [16] ...... 81 6.11 Water use [21] [19] ...... 82 6.13 Hydraulic Retention time approximation for the vermifilter size 83 6.14 Hydraulic loading ...... 83 6.15 Worm Distribution ...... 84 6.16 Removal rates ...... 84 6.17 Final effluent ...... 85 6.18 Estimates of Lighting duration ...... 87 6.19 Comparison between different MFC performances ...... 89 6.20 Estimates of light bulb consumption options for housing: Source easyearth ...... 90 6.22 Power Generated from a single cell ...... 92 6.21 Number of operating cells required for each duration and dwelling 92 6.23 Power Generated from a single cell (Grey water) [26] . . . . . 93 6.24 UV Dosages for 1=log Inactivation of various organisms . . . 96 6.25 Water quality with UV installation in mg/l ...... 97 26 TSS Removal efficiency ...... 101 27 Turbidity Removal ...... 101

28 BOD5 Removal ...... 101 29 COD Removal ...... 101

Page 11 List of Figures

1.1 Comparison of indoor water between 1999 and 2016 [2] [27] . .7 1.2 Urine Separating Toilet ...... 15 1.3 residential water uses divided by activity and appliance [27] . 16 1.4 The TIR urban landscape requirements [27] ...... 17 1.5 Residential Rainfall Harvesting System [20] ...... 18 1.6 Rainwater Harvesting estimation [20] ...... 19 1.7 Compliance to discharge norms between developed and developing countires.Source:von Sperling and Fattal, 2001,von Sperling and Chernicharo,2002 ...... 23

2.1 Objectives of wastewater management [28] ...... 25 2.2 Treatment/ Disposal methods [29] ...... 28

3.1 Example of LM,South Burlington plant, Source (Todd 2003) . 31 3.2 Diagram of LM and its components,Source:Ochsendorf,Adams and Connor.Design for sustainability,MIT open course ware . . 41

4.1 Components of a typical MFCs and its working principle [30] 48 4.2 two-chamber MFC in five different configuration: (A) cylindrical shape, (B) rectangular shape, (C) miniature shape, (D) cylindrical upflow configuration, (E) Cylindrical U-shaped cathodic compartment. Adopted from Delaney et al., 1984; Allen and Bennetto, 1993; Ringeisen et al., 2006; He et al., 2005, 2006)...... 51 4.3 cylindrical single compartment MFC with eight graphite rods (anode) surrounding the cathode. Source ((A) with modifications after Liu et al., 2004. (B) drawn to illustrate a photo in Liu et al., 2004.) ...... 52

12 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

4.4 vertical(A) and plan view (B) of up-ﬂow MFC. Source Jang et al., 2004; Tartakovsky and Guiot, 2006, respectively. . . . . 53

5.1 Comparative results of vermiﬁltered and controlled kit [31] for (1) TSS (2)Turbidity (3) BOD (4)COD ...... 68

6.1 Water Saving Results with UD ...... 78 6.2 final effluents from the ue of the LM ...... 79 6.3 Schematic of stream division/LM system in an apartment building...... 80 6.4 Schematic of Vermifiltration system ...... 85 6.5 Scheme of the Vermifiltration treatment in a single house . . . 86 6.6 Power density and Voltage progression in time [32] ...... 91 6.7 Performance of grey water powered MFC [26] ...... 93 6.8 Scheme of the MFC treatment in a single house or Apartment 94 6.9 Comparison between disinfections approaches for wastewater [33] ...... 95 6.10 Influence of the UV contact time of the treated wastewater [33] 96

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Abbreviations

AEES Advanced Ecologically Engineered Systems DO Dissolved Oxygen EDCs endocrine disrupting chemicals FAO Food and Agriculture Organization GDP Gross Domestic Product HLR Hydraulic Loading HRT Hydraulic Retention time LED Light Emitting Diodes LM Living machines Lpcd Liter/capita/day Lpd Liter/day MFC Microbial Fuel Cells NPK Nitrogen- Phosphorus- Potassium OC Oxygen Comsumption PAHs polycyclic aromatic hydrocarbons PEM Proton Exchange Membrane pH Potential of Hydrogen REU Residential End Use RVC Reticulated Vitreous Carbon SS Suspended Solids TIR Theoretical Irrigation Requirement UD Urine Diversion UDDT Urine Diversion Dehydration Toilet UK The United Kingdom USEPA United States Environmental Protection Agency UV Ultra Violet wcs Worst case Scenario WHO World Health Organization

Page 14 Acknowledgements

I would like to oﬀer my undivided gratitude and thanks to my supervisor Manuela Antonelli for her consistant encourgement,support and technical guidence throughout this project, and to Eng.Riccardo Delli Compagni for his advice. A very special gratitude goes out to Arch. Francesco Giacomo Panzeri for his unfailing support and assistance with the visual aspects of the project.

I would also like to thank my Family and friends for being the best emotional and moral support along the way.

And Finally, last but by no means least everyone at Politecnico Di Milano who helped me during my pursuit for the Masters Degree. Abstract

Biological wastewater treatment technologies are emerging approaches for water treatment that has the potential for use in developed and developing countries, whether in a rural or urban plan.This study analyzed three biological treatments that are: Living Machines (LM), Vermifiltration and Microbial fuel cells for the treatment of municipal wastewater. This study evaluated the amount of water saved and redirected for reuse (based on the chemical characteristics of the final effluent) and the generated benefits (products as fertilizers and energy as in electrical energy) from using these forms of treatment in three residential scenarios applicable and approximate to existing urban plans. This study used successful installations tailored to fit the water usages of the designated plan to evaluate the applicability of this technology to offset and reduce the burden created by wastewater on the indicated ecosystem, to minimize the monetary expenses on the residents and eliminate some con- sumptive practices such as electricity and fertilizer purchasing prices.

Reader note Each chapter- except the ﬁnal chapter- give a theoretical description of the biological treatments and their operation, While the ﬁnal chapter represents the practical implementation of these technologies in the residential setting. Abstract

Il trattamento biologico delle acque reflue mediante processi sostenibili èun approccio emergente con un potenziale per l’utilizzo nei paesi sviluppati e in via di sviluppo, sia in ambito urbano che rurale. Questo studio analizza tre trattamenti biologici: living machines (LM), vermifiltrazione e microbial fuel cells (MFC). Lo studio ha valutato la quantitàdi acqua risparmiata e ind- irizzata al riuso (in base alle caratteristiche chimico-fisiche del dell’effluente finale) e i benefici ottenuti (prodotti recuperati, come i fertilizzanti, ed ener- gia elettrica) derivati dall’uso di queste forme di trattamento in tre scenari residenziali applicabili e approssimati alle tipologie urbane esistenti. Lo studio ha stimato il consumo idrico nei casi in esame, valutando quindi la fat- tibilitàdi tali soluzioni, in modo da compensare e ridurre il carico inquinante generato, minimizzare l’esborso economico dei residenti ed eliminare alcune spese come l’acquisto di elettricità. 1 Municipal wastewater

Introduction

The current and predicted growth in the world population and urbanization has a direct impact on the quantites of municipal wastewater. Munic- ipal wastewater is defined as the effluent of water from urban settings such as residential areas, offices and commercial areas that are collected in the same sewer system to be sent for the perspective treatment techinque.This growth in municipal wastewater is inversely related to the absorption ability of pollution loads in the environment,which is declining, leading to the necessity of adopting new techniques that favourably comply to the current green revolution. A suitable assessment technique of the municipal wastewater is the use of a water-quality study of municipal wastewater discharges, that provides the sufficient input to be assimilated in water reclamation and quality assessment models. This category of studies quantifies the flowrates of a system and the frequency loads of usage, furthermore the contaminants and their deterimental effects on all exposed receptors, additionally the loads of the pollutants at the final discharge point. Water-quality studies are implemented to further improve existing dynamics and to define and identify salvageable volumes of wastewater and potenial reuses, leading to improved management and reduction in overall wastewater flows. The evaluation of local or residential wastewater volumes is usually referred to as Microscaling models, these type of models are decribed either by detailed skeletonization or simplicity. The use of a microscale model in this study is sufficient in the understanding of the performance of the collection systems. On the contarty the implementation of Macroscale models give a

2 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings qualitative assessment rather than a quantitative one, by spatial division of the targeted area into nodes per 1000 population that is irrelavent in this scope [34].

The division of the wastewater volumes is linked to Wasterwater footprint that deﬁnes the diets and consumed household material and applied activities that contribute to the wastewater. The analysis of the wastewater provides information on diet,sex, pregnancy, use of drugs and narcotics, hy- giene,alcoholism, environmental consciousness, diseases, etc. These strongly inﬂuence the environment and give a starting point for the remediation and mitigation plans. [35]

Water Consumption

The domestic wastewater ﬂow is a function of the water consumption by the population in a given habitual setting,after substracting the consumed volumes for drinking and eating and various activities and with refernce to some undeniable losses such as piping leakage. this is presented in table 1.1 : Table 1.1: per capita water consumption rates [1]

Community number of in- consumption habitants in Lpcd City > 250, 000 150 — 300 Average town 50,000–250,000 120 – 220 Small town 10,000–50,000 110 – 180 Village 5,000–10,000 100 – 160 Rural settlements < 5, 000 90 – 140

The categorization of the diﬀerent communities was based on the same governing factors to obtain a reference baseline for evaluation and the increase of the reliability in this division.These consumption rates are aﬀected by the subsequent factors:

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1. Economic level of the community: the water consumption, and hence the wastewater production rates are proportional to the higher income rates. 2. Population: the number of inhabitants is related to the increase of the consumption as showed in table 1.1. 3. water availability and extraction: areas with deﬁcit have lower consumptions. 4. Water Cost: a comparison is due between the cost of attaining the water and the average income rates in the speciﬁc community. 5. Water Pressure: higher pressures are the cause of poorer management of the amount of water required for a given practice, since the higher pressure values could be damaging to the conduits and devices used for the conveyance of water.pressure should be tailored according to the acceptable level of the apparatus used. 6. Climatic Conditions: higher temperatures cause higher consumption rates. 7. Level of Development: the more developed areas require a larger usage footprint. 8. Household metering: the metering of the waste consumed prevents excessive use and increases the level of water awareness. 9. Losses: due to leakages and emergency actions.

Wastewater Flows

The evaluation of the residential wastewater and its future prospects is dependent on the quantification of the flow and possible stream divisions,that is based on the final required water characteristics for a precise reuse of the resource. The flows in a wastewater system are usually described to fit various temporal arrangements illustrated as the following: • Diurnal — The sanitary flows and their variation during the course of a day (a 24-hour cycle).

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• Weekly — this represents the flows within a week time period . • Seasonal — this addresses the variation in the flowrates throughout different seasons in the year. • Present/Future — the flow estimates during the estimated design years of the designated system.

The wastewater ﬂows and the parameters adopted in quality studies are commonly used to account for worst case scenarios; made by the evaluation and calculation of peak and instantaneous increases in the water volumes, giving a holistic approach within the dedicated period of study. [34]

Residential wastewater ﬂow division

To identify the consistuent ﬂows in a municipal wastewater,a priliminary calculation of the overall produced wastewater has to be estimated. The criteria for this estimation is through the deﬁnition of the analysed unit. for the purpse of this study the sectioning addressed three categories as referred to in 1.2 .Furthermore, the discharged wastewater from individual appliances was indicated by evaluating the amount of water each device consumes during its operation and this has been depicted using in 1.3. Table 1.2: Wastewater Rates for Residential establishments [2] [3]

Use ﬂowrate(Lpcd) Apartment house (de- 300 — 400 centralized) Apartment house 300 — 500 (centralized) Boarding house 150 — 220

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Table 1.3: water use for household devices [4] [5] [6]

Device Range Unit Top loading washing machine 130 — 216 L/load Front loading washing 45 — 60 L/load machine Dishwasher 36 — 60 L/load Bathtub 114 L/use Kitchen food-waste grinder 4 — 8 L/day Shower 9 — 11 L/min-use Standard Toilet tank 15 — 23 L/ﬂush Conservation Toilet tank 6 — 13 L/ﬂush Washbasin 8 — 11 L/min-use Kithchen Sink 11 — 25 L/day

As reportd by Meyer et al. (1999) [36] the indoor water use (wastewater ﬂow) for a dependent household was obtained with the equation 1.4

y = 141x + 262Lpd (1.1)

Where y = indoor water use per household ( Lpd) . x = number of residents per household.

The REU1999 and REU2016 for the divided uses of water show a considerable decrease in the consumption rates moves towards a water saving future as depicted in Figure 1.1

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(a) Average daily indoor per household water use REU1999 and REU2016

(b) Average daily indoor per capita water use REU1999 and REU2016

Figure 1.1: Comparison of indoor water between 1999 and 2016 [2] [27] .

Municipal Wastewater Characterization

The composition of the wastewater is governed by various factors as the personal GDP, the urban planning, climatic conditions and others as mentioned previously. Moreover the consistuents of the wastewater are divided into categories based on their origins, whether physical, chemical or from organic origins.This is evidently showed by Henze et al., 2001 in table 1.4,

Page 7 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings with each dominant component imposing a level of risk that is harmful to the perspective users. The increase in the radioactive intensity of the water reflects an increase in the carcinogenic potency and genetic mutations of the exposed final receptor: Main Components Globally it is customary to define the wastewater quality measuring parameters as indicated in table 1.5, where the components were measured for highly concentrated wastewater flows, Diluted and regular concentrations. Afterwards a more detailed analysis is carried out according to the specific activities and routes that the water undergoes to assess toxicological level for specific measurement elements,which is a specific count of microorganisms or type of radiation..etc: Degradability The main and most important treatment mechanism for the municipal wastewater is the process of removing and stabilizing the organic component of the waste, if disposed improperly it represents a source of a wide array of ail- ments and threatens the general public health.The components of wastewater,whether undergoing conventional or sustainable treatments hold a certain degree of biological degradation as shown in table 1.6: Table 1.6: Contamination measures and their degree of biodegradation in g/m3 [1]

Parameter Biodegradable Inert Total

BOD5 350 0 350 P 14.7 0.3 15 Organic N 13 2 15 Total N 43 2 45 Total COD 570 180 750 Soluble COD 270 30 300 COD partic- 300 150 450 ulate

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Table 1.4: Domestic wastewater consistuents [7]

Wastewater Consistuents Effect / Example Risk Biodegradable organic ma- Oxygen depletion Fish death, odours terials Other organic materials Detergents, Bioaccumulation, pesticides, toxicity, aestheti- grease,colouring cally unpleasent solvents, phenols, cyanide Nutrients Nitrogen, phospho- Eutrophication, rus, ammonium oxygen depletion, toxic effect Metals Hg, Pb, Cd, Cr, Toxic effect, bioac- Cu, Ni cumulation Other inorganic materials Acids, for example Corrosion, toxic ef- hydrogen sulphide, fect bases Odour (and taste) Hydrogen sulphide Aesthetic inconve- niences, toxic effect Microorganisms Pathogenic bac- Risk when bathing teria, virus and and eating worms eggs Radioactivity Toxic effect, accumulation

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Table 1.5: Main and mutual wastewater components in g/m3 [1]

Parameter Diluted Regular Concentrated

BOD5 230 560 350 Total COD 500 750 1200 N 30 60 100 P 6 15 25 TSS 250 400 600 VSS 200 320 480 VFA 10 30 80

Biology of Domestic Wastewater:

Since a large amount of the municipal wastewater is made-up from organic matter (later becoming the sludge), this makes it a suitable environment for several species (mostly microscopic),The principal organisms in the domestic waste water include: • Bacteria: Unicellular organisms resposible of the waste stabilisation, but are in most conditions pathogenic. • Algae: Oxygen producing photosynthetic organisms. • viruses: Parasitic organisms. • Protozoa: Aerobic or facultative, they feed on bacteria and algae and are in some cases pathogenic. • Fungi: decomposing organisms. • Helminths: Helminth eggs cause diseases. • Archaea: Similar to bacteria, but they proliferate in anaerobic conditions. [1] Metals in municipal wastewater

Metals in the residential wastewater is indicated as a fraction of what is usually referred to as the inorganic contaminants.within these metals other distinctions could be made to define the effect of the metal, As the suscep- tibility to corrosion, toxicity or differently the distinction into heavy metals and light ones. The domestic wastewater contains an amount of metallic substances, The ones with the most relavence are described in table 1.7

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Table 1.7: Metallic contamination values in residential wastewater in mg/m3 .Source [8], [7] and [9].

Metal Low Medium High Al 350 600 1000 Cu 30 70 100 Hg 1 2 3 Au 3 7 10 P b 25 60 80 Zn 100 200 300 Cd 1 2 4 Cr 10 25 40

Indoor wastewater

The household wastewater quantity and quality is inextricably linked to the associated human activties of the residents, but generally it is quantiﬁed on an annual norm accordingly: Table 1.8: Annual amount of main domestic wastewater components [10]

Parameter Kitchen bath/Laundry Toilet Toilet (Urine Total Unit (total) Separating )

BOD5 11 1.8 9.1 1.8 21.9 kg/yr COD 16 3.7 27.5 5.5 47.2 kg/yr P 0.07 0.1 0.7 0.5 0.87 kg/yr N 0.3 0.4 4.4 4.0 5.1 kg/yr K 0.15 0.15 1.3 0.9 1.6 kg/yr

A detailed description of the indoor wastewater is made by the segmentation of the wastewater into streams as: Kitchen Wastewater

Kitchen waste contain a signiﬁcant amount of organic matter that could be retrieved and used in biomass, the division of this part of the wastewater

Page 11 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings is easily made through the application of cleantech cooking,thus reducing the organic load. Cleantech cooking is the process of discarding the food remains in a specified bin rather than flushing it.The remaining grey water from the kitchen after minor treatments could be used in watering plants and toilets’ flushing (Danish EPA 1993). The use of a Garbage disposal in the kitchen sink is another option of creating cleaner streams,It is preferred to be connected to a solid waste collection system for ultimate gain of substances to be used as compost and biomass production. Bath and Laundry wastewater

This wastewater is contaminated with chemicals from personal care products and the use of detergents.The level of contamination is minimal, and hence complete recycling of the water is feasible to meet irrigation and ﬂush- ing standards. The applicability of these methods shows promising results in the reclamation and recovery of material in domestic wastewater as given by Table 1.9. Table 1.9: Reduction with Urine Separation and Cleantech cooking in g/m3 [11].

Technology Conventionl Urine Sep- Cleantech aration cooking

BOD5 60 35 20 COD 130 55 32 P 2.5 0.5 0.4 N 13 2 1.5

Toilets’ wastewater

Separating Toilets produce two types of wastewater that are grey water and black water that vary in their intensity level (concentration of organic materials) as mentioned the use of urine separation units creates controlled treatment conditions and facilitates the reuse and reclamation rates, the characteristics of the created separate streams is demonstrated in table 1.10

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(Low values can be due to high water consumption or Low water consumption (based on the concentration levels). Table 1.10: Characteristics of grey and black wastewater [12].

Parameter Grey water Grey Wa- Black wa- Black wa- high ter Low ter high ter Low

BOD5 400 100 600 300 COD 700 200 1500 900 P 7 2 40 20 N 30 8 300 100 K 6 2 90 40

To obtain a more comprehensive understanding of the retrievable nutrients from the toilet water a characterizetion of the content is to be made based on the diﬀerentation between the solid and the liquid content that will eventually be broken down by microorganisms to useful products in agriculture (the green areas surrounding the designated building to be accurate). This is well depicted in 1.11: Table 1.11: Composition and Quantities of Urine and Human Faeces in urban wastewater [13].

Urine Faeces Approximate Composition % Moisture content 93–96 66— 80 Organic Matter 65–85 88–97 Nitrogen 15–19 5.0–7.0

Phosphorus (as P2O5 ) 2.5–5.0 3.0–5.4

Potassium (as K2O) 3.0–4.5 1.0–2.5 Carbon 11–17 44–55 Calcium (as CaO) 4.5–6.0 4.5

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Quantity Control For Toilets From table 1.8 it is easy to conclude that using urine separation toilets as- sists in the conservation of resources and the redirection in the wastewater, Moreover the progress to reach sustianable municipal wastewater treatments could be founded on: • The concept of stream separation that entails the division of the indoor and outdoor produced wastewater into multiple streams with the intent of recovering the largest amount of beneﬁcial elements and reducing the energy consumed in the treatment process. • Reduction of the generated waste by installing conserving devices and/or adopting new dietary behaviours, with this concept depending on the increase in the societal awareness levels.

There are two utilized types of urine diversion units that are equiped for indoor wastewater separation, the urine diversion dehydration toilets UDDT wrongfully indicated by the name ”ecosan Toilets” where the treatment and separation are carried out in the absence of water. The more suitable option for residential and urban developments with existing infrastructure is using UD ﬂush toilets that adopt the use of water as the driver for the rinsing mechanism, for further control of odors and water consumption it is preferred to accompany the system with vacuum control for better suction. It is to be mentioned that the separated volume of urine is assimilated in a two phase collection system.Firstly the collection tank ,and secondary the sanitisation and reuse tank. The estimation of these units is based on equation (1.2) :

Vstorage = Nusers ∗ purine ∗ tstorage ∗ ftimefraction (1.2)

The urine storage tank is used for the practical application and supply of the urine in agriculture ,due to the high content of urea, there should be a scheduled admission period for the urine entrance in the tank -to avoid its

Page 14 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings mixture with freshly receieved urine- to increase the concentration levels per liter of the ammonia that is the targeted nutrition factor.

Figure 1.2: Urine Separating Toilet

There exists some on-site waste handling systems that help increase the ben- eﬁts of separtion with focus on areas where a centralised treatment is not feasible, Some of these technical installments are: 1. The use of Septic tanks ensued with inﬁltration systems, these are usually incorporated in an area where decentralised wastewater systems are applied. The use of this option is easily implemented in developing countries. 2. Composting Toilets, are commonly used in agricultural areas with residential facilities. 3. Night Soil Systems, also to partially replace chemical fertilizers. [35]

The indoor water use shows to be declining even with the increasing population rate. This can be translated in the use of ﬁtting technologies and the submission to the policy acts and regulations. To conclude the water consumption in a single household can be summerized in Figure1.3 :

Page 15 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Figure 1.3: residential water uses divided by activity and appliance [27]

Outdoor wastewater

The outdoor water use is deﬁned as the volume of the water used in residential and urban developments for Landscape irrigation (by hose bibs, spriklers, drip irrigation, etc.), vehicle washing, Swimming pools backwashing, pavement cleaning and so on and so forth. when talking specially about pavement cleaning one has to address that this activity is regularly conducted by the municipalities, but not to forget that the water volume utilised originates from the residential water supply network [12].

The evaluation and the assessment of the outdoor water requirment for a precise urban setting is built on the estimation of the TIR regularly calucu- lated using the Penman-Montieth 1.3 equation with the initial assumption that the outdoor requirement is tranlated into optimal plant growth for agricultural crops [37].

o Etsz = (0.4084(Rn−G)+γ(Cn/(T +273))u2(es−ea))/(δ+γ(1+Cdu2)) (1.3) following that the outdoor area is calculated as the area of the Lawn, side walks, parking lots, building footprint and swimming pool, to be used in the subsequent calculation1.4

Irrigated area ∗ ET rate ∗ 0.6233 = Volume of Water requirement (1.4)

The TIR demonstrated by the graph 1.4 shows that for a given urban community 72% of the residents ustilize less than the allocated volume for outdoor

Page 16 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings water, and 16% use the targeted amount of outdoor water and with 13% exceeding the designated quota.This shows that the excessive use is often compensated by the lower consumption, bearing in mind that the installation of a monitoring system will provide better resource and energetic savings, giving a precise distinction to the quota consumed by speciﬁc users.

Figure 1.4: The TIR urban landscape requirements [27]

Rainwater Harvesting

The scarcity in water sources world wide to meet the growing demands led to the emegrence of the rainwater harvesting technology, that collects rainfall water from building roof tops and redirects it to balance and oﬀset the burden on the water supply and distribution and using this water for irrigation, potable and non-potable demands as domestic toilet, laundry, hot water and outdoor usages [19] [20].The havested rainfall is suitable to be considered as a water resource and could be analysed in terms of cost and quality. As demonstrated by Coombes and Kuczera, (2003) investing in a rainwater harvesting system and integrating it with the existing system generates economic bene- ﬁts, whilst preserving the ecosystem where the urban water cycle takes place.

Methodology and operation

In a rainfall harvesting system, the rainfall is collected from the rooftops and transmitted through pipes to a tank that permits the discharge of the

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Figure 1.5: Residential Rainfall Harvesting System [20] surplus volumes in the wastewater collection system.The presence of the tank allows storage ,and this makes the use of this technique feasible even in very arid areas .Figure 1.5 shows a rainfall harvesting system design for residential buildings. from ﬁgure 1.5 the mass balance is carried out according to [20]:

It = Rt ∗ A ∗ ϕ (1.5)

Vt = It + Vt−1 − Ot − SPt (1.6)

Rainwater harvesting in multistorey residents In most metropoles the residential unit is usually apartments in multistorey buildings to absorb the growing population rates and to move towards a vertical growth instead of a horizontal urban sprawl, forced by the scarcity of empty lands and heavy interference with the natural enviroments.Referring to a study by Rahman et. al (2010) [19] the havesting system was estimated

Page 18 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings for multistorey residents that coincide with the most regular surface areas for buildings 2000 and 4000 m2 with a roof area of 800, 1600 m2 respectively, with the different arrangements of floors, it was assumed a number of four apartments per floor and 3 persons per apartment as the design baseline: (a) Four floors with 16 apartments and 48 persons (b) 6 floors with 24 apartments and 72 persons (c) 8 floors with 32 apartments and 96 persons.

The quantiﬁcation of the captured rainfall and its distribution has been made and depicted in the schmatic diagram in ﬁgure 1.6 , along with the sizing and volume of the storage tank .

Figure 1.6: Rainwater Harvesting estimation [20]

It is notable that not all the rainfall water is captured in the havesting system and transported by the downpipe to the tank,but parts are lost due to surface wetting, evaporation, ponding in depressions,leaks, surface splashing and ﬁrst ﬂush retention ,and were assumed to be 15% of the total rainfall.The outcome of the rainfall harvesting is showed in 1.8:

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Number of ﬂoors Scenario Area m2 4 6 8 with conserva- 2000 446 511 545 tion 4000 554 678 762 Without conser- 2000 546 579 598 vation 4000 773 870 934

Table 1.8 shows the water savings are proportional to the number of ﬂoors and to the surface area of the roof, However it is also observed that the non-conservative consumption plans have higher volumes of the conservative ones and this could be assigned to the use of more powerful pumping systems with the non-conservative plans since they require higher volumes of water. a proposed system for the sustainable allocation of the residential wastewater using the above mentioned technologies is explained in ﬁgure ?? [19] [20].

Wastewater in Developing Countries

The criteria for domestic wastewater treatment in developing countires is governed by diﬀerent priorities than those of their developed counterparts.It is of crucial importance to use minimal energy and speediness in the treatments, this usually implies the use of chemical materials that are environ- mentally damaging, but inexpensive and easy to obtain. Alongwith simiplic- ity in incorporation, operation and maintenance (both in cost and labour)is favoured,with high performance and minimal sludge reduction [38]assumed to be the elements of constructing wastewater management plans,but are overlooked due to the lack of subsidies and incentives from the governement (high levels of corruption. The water use in some developing countries is better stated in table 6.4 [34]:

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Table 1.12: Water consumption in developing regions

Country or Region gpcd Lpcd Africa 4-6 15-23 China 21 80 Latin America and 19-51 70-190 Caribbean Southeast Asia 8-19 30-70 Western Paciﬁc 8-24 30-90 Eastern Mediter- 11-23 40-85 ranean

Wastewater Characteristics in Developing countries The composition of the wastewater produced in developing countries varies from one region to another deending on the usage prectices, but a gener- alised estimation is made in table 1.13 [14] , It is worth mentioning that because of the simplicity of the life style in the regions it is of rare nature to ﬁnd high levels of contamination caused by heavy metals and toxic materials, and hence it is usually not a priority in investigation and mitigation plans since they would require technical aspects that could be monetary burdensome, resulting in increased tax rates imposed on the population by the governments [1].

Compliance to Legislations

The main prespective of the imposition of standards for the wastewater is to ensure environmental protection and the revival of ecosystems, This will eventually result in health and environmental development.The progression of developed countries has already been reached, while developing countries find it difficult to pertain and comply to the norms due to the lack of the adequate implementation techniques and deficit of competent of mangerial bodies.The lack of the proper infrastructure in the developing countries sometimes could result in lowering the regulatoy limits leading to the deterioration of the enviromental aspects, This is mainly due to altering decisions accord-

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Table 1.13: Investigation and measurment characteristics of wastewater in Developing Countries [14] [1]

Parameter (g/inhab.d) (g/inhab.d) Typical Concen- Range Concen- Typical Range tration (mg/l) tration (mg/l)

BOD5 50 40–60 300 250–400 COD 100 80–120 600 450–800 pH – – 7.0 6.7–8.0 Organic Phos- 0.3 0.7–1.0 2 1–6 phorus Inorganic Phos- 0.7 0.5–1.5 5 3–9 phorus Organic Nitro- 3.5 2.5–4.0 20 15–25 gen Nitrate 0 0.0–0.3 0 0–2 Ammonia 4.5 3.5–6.0 25 20–35 Fixed sus- 10 7–14 80 40–100 peneded Solids Volatile sus- 50 25–60 320 165–350 pended Solids Dissolved Fixed 70 50–90 400 300–550 Solids Dissolved 50 35–60 300 200–350 Volatile Solids Settleable – – 15 10–20

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Figure 1.7: Compliance to discharge norms between developed and developing countires.Source:von Sperling and Fattal, 2001,von Sperling and Cher- nicharo,2002 ing to the political reasoning.

The Guidelines for the wastewater management and quality are set by the WHO, and afterwards a specialized and unified plan should be made for the region, depending on the economic, climatic and cultural conditions.The application of these laws should target risk reduction and mitigation based on logical and scientific grounds. The Guidelines could be categorised accordingly: • Standards for possible reuse of water in a specific realm (e.g Irrigations or toilet flushing) are to identified and agreed upon by the authorities involoved. • Discharge and emission control, In order to minimize and eliminate the tedious and diffucult disposal of the harmful treatment residues into the end point discharge ecosystem (usually the natural water streams such as rivers). • Quality standards for treatment endpoints compatible with geographical orientation and degree of urbanization [39]. A comparison in complying to legislations was conducted by Sperling and Fattal as shown in 1.7.

Page 23 2 Sustainable treatment Tech- nologies

Introduction

The shift and change in the treatment technologies from conventional - whether centralized or decentralized - to sustainable approaches is relient on the full apprehension of the receiving environment and the adequate enforce- ment of planning and policies.Even in the case of decentralized treatment technologies they should be managed using a centralized management and control to attain systematic maintenance and inspection that is fitting to agreed upon treatment thresholds. The management strategies are tailored to the cultural, economic, environmental and social conditions in the target area . The differentiation between the centralized and decentralized technologies - besides the management- could be allocated to the high initial investment and infrastructure costs.This could be further controlled through the imposition of management by increasing the afforadability of wastewater management systems and with consideration to the available human resources, climate conditions, financial, social and cultural acceptance levels [40].

Choice of Technology

It is of importance to mention that the distinction between the centralized and decentralized treatment systems is in the fact that the centralized systems adopt large quantites of wastewater that are owned by public authorities. The system usually devides districts into communities and connects them using large piping facilities and allows access through manholes.As

24 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings opposed to the centralized systems, the decentralized approach treats the wastewater locally and at close proximity of the points of generation (individual buildings and dwellings) [28] [29] .The general approaches for waste management can be summed up in the following ﬁgure:

Figure 2.1: Objectives of wastewater management [28]

Even though different treatments -especially for decentralized systems- exist, it seems that the most applied one is the spetic tank with disregard to the other factors that could be influential in the selection criteria, because their installation is easier and more cost efficient in terms that the technology is well known in various regions. the objectives to be reached include addtional categories: Socio-economical factor : is reduced in its load and its consumption of the allocated treatment budget and societal burden due to the worri- some related to the treatment and implementation of new technologies in wastewater treatment. Energetic factor : through the proper handling power and energy can be extracted from the treatments and serves as a valuable output instead of being a difficult but viable input [29]. Self-sufficiency :in the light of the aforementioned information the term self-sufficient is strongly linked to the notion of the green revolution

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and creation of sustainable process [29].

Overview of current treatment Technologies

1.Primary treatment techniques: The main function of these systems (septic tanks being the most common) is the removal of settleable materials removal and the promotion of organic matter digestion.The Imhoff tank is another form of primary treatment that assimilates higher flow rates than those of the septic tank. Both systems are not effective in the removal of N and P ,along with the difficulty in odor management and control (could be an indicator in the reduction of treatment ef- fectivness).To avoid the loss in the efficiency it is common to install a filter prior to the unit’s inlet point to achieve earleir separation of sludge.Primary treatment technologies are used in areas with land restriction, high level of groundwater and poor soils [41].

2. Secondary treatment techniques The secondary treatments usually contain a ﬁlter media that is most likely to be sand. And in the case of deep permeable soils an absorption systems must be used, as opposed to complicated onsite systems that is to be used in areas with shallow and impermeable soil.The secondary treatments contain various methods with the most common and widespeard being the following:

a. Constructed Wetlands: Constructed wetland occupy lesser land than the systems of surface disposal and they release less odor (less pollutant emissions to the air),They are classiﬁed as inexpensive to operate and control and they could support wildlife.The advantages associated with this treatment is that it is intolerant to overloads of ammonia and it requires a continuous water supply [41].

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b. Aerobic Lagoons: The effluent released can be used in irrigation, the aerobic lagoons are effective in pathogen removal, although it is not effective in heavy metal removal and to meet the discharge standards they require additional treatment units that work as disinfectants [41].

c. Anaerobic Lagoons: Also charecterised by operating and maintenance simplicity.They don’t require an areation system (cost eﬀective),but produce methance coupled with lower biomass per unit of organic laoding, hence lower sludge production. The dis- advantages are that they cannot be use din cold regions or for domestic waste water classiﬁed with low BOD levels and the odor release through the methane production [41].

d. Facultative Lagoons: They are eﬀective in pathogen removal and the removal of BOD,SS and ammonia, but are not powerful when it comes to heavy metals. and they represent a treatment that combines aerobic and anaerobic lagoons through the use of facu- latative degrading bacteria that adapts to the DO levels [41].

e. Sequencing Batch Reactor: Requires higher control and manag- ment for operation.An advantage of this form of treatment is that is occupies lower land footprints and achieves higher removal rates of nitrogen,organic and suspended soids content, that is necessary in the land and water conservation [41].

f. Suspended and Attached growth: These need electricity and require high initial investment costs in order to capture the solids and they simulate extended aeration treatments. A level of nitri- ﬁcation is unavoidable, alognside with odor and noise release. [42] [41].

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Treatment and Disposal:

They provide additional treatment before reaching the end-point of the processes and can be made through simple techniques such as evaporation and evapotranspiration, or more complex made by subsurface infiltration that differs according to the soil absorption rates.Other techniques that are based of seepage capacity are trenches and seepage pits where the water table is too low. when using a mound system, it shows greater allowences to different soil characteristics and groundwater conditions [29]. A better illustration of the disposal treatments is given by 2.2

Figure 2.2: Treatment/ Disposal methods [29]

Since the governing pollutant in municipal wastewater is organic, this study has been based on discovering and simulating the treatment eﬃciency of the novel biological treatment methodologies particularly LM, MFC and ver- miﬁltration,that are preferably coupled with coagulation, precipitation, and

Page 28 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings membrane ﬁltration to improve the treatments.With each treatment methodology broadly explained in the following chapters.

Page 29 3 Living Machines

Introduction

Biological living machines LM or AEES are a manifestation of the ability to transcend conventional and current technology towards biomimicry in wastewater treatment. It is based on the paradigm shift through the implementation of bio-concepts to substitute chemically dependent processes. The basic unit of the LM is the minutiae ecosystems where the treatment of the wastewater is performed through natural mechanisms such as metabolism, soil absorption and other processes. The concept of nature mimicry showed great potential in the water quality improvement realm as for lake and pond water purification; which is essential in artificial and also natural existing examples; since the man induced contamination can be overpowering to the natural processes for restoration and treatment of an ecosystem and in the case of lakes and ponds it has an increasing difficulty due to water volume stagnation [43] [44].

The operating mechanism of a LM comes from simulating and creating a replica of down-scaled ecosystems through favourable survival conditions. The incorporation of the ecological engineering principles of a LM will ad- ditionaly inﬂuence waste reduction, biomass production (from the use of organisms in the remediation process), fuel generation and in many cases urban and architectural planning and designs. The survival of the mesocosms and microcosms is described by the operating continuity of the LM as the assimilated ecosystems could proceed to reach steady or imbalanced chaotic states; depending on the proliferation and growth of the organisms with the selected species, initial boundary and critical conditions.

30 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Figure 3.1: Example of LM,South Burlington plant, Source (Todd 2003) The variety of enzymatic pathways, nutrients and gas exchange surfaces, provide a wide platform for treatment modules with different orders of magnitude ,and thus might take place of the present-day chemical and mechanical techniques.this will eventually lower negative environmental impacts and emission levels, with the final aim of obtaining ”zero” emissions industrial effect. [45] [46]

The use of a LM leads to a reduction in the stress linked to the supply water and wastewater infrastructure; by creating a decentralized and localized treatment system that filters blackwater and other streams of water involved in urban and residential wastewater in this case. The contaminant removal is obtained through cascading processes, where each stage removes a certain amount of pollutants, making the effluent from one of the reactors a suitable influent for the ensuing treatment process.

Economically, the traditional wastewater treatments are somewhat monetary burdensome, even though the endpoint of the treatment is safely dis-

Page 31 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings posed water, it is achieved through the imposition of a bulk of economic drain on the community. As opposed to that the LM could generate economic benefits by producing marketable products as biomass for commercial fuel generation, plants and fish (the controlled environment could play a role in the nourishment of some species that cannot thrive naturally due to the environmental modifications to their habitats caused by anthropogenically driven pollution).Once the treatment is initiated the use of the LM reflects self-sustaining operation traits, where the system runs itself with periodical plant thinning and greenhouse structure renovation in colder regions, furthermore in a timeline ranging from four to seven years a replacement of the liners in aerobic tanks is to be made a realistic illustration of the system is showin in figure 3.1 [47] .

Successful Installments of LM

With the ever-growing necessity to sustain resources and reduce detrimen- tal material accumulation from which landﬁll disposal of waste is a monumen- tal factor in negatively aﬀecting and contributing to global warming, there is a continuing need for innovation in wastewater treatment and handling. A certain amount of relief can be manifested through the amalgamation of ecological engineering to the conventional approaches and techniques, where an inextricable linkage between living and non-living parts is made.

One of the preliminary installments of LM is the one at the Findhorn Foundation in Scotland in 1995, that was designed with a capacity to treat the sewage coming for the 300 facility’ residents. This facility has been a pivotal point in the assessment of the success of the implementation of the LM in the UK and thus an increase in the government and local endorsements to further improve the technology. The machine meets the tertiary sewage outﬂow standards and treats an estimated 65000 L/day, it is worth mentioning that this precise project has been endorsed by the local Water and River Authorities showing the relevance of the political and ecological fronts to confer and be subject to environmental treaties and

Page 32 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings protocols. [48]

The LM in Oberlin College’s Adam Joseph Lewis Centre for Environmen- tal Studies in Ohio is to treat a quantity of wastewater up to 7571 L/day in a facility resembling a garden-like atmosphere. The treated water is then recycled again to be used in non potable water uses such as toilets flushing, but firstly it runs through a disinfection phase using an ultraviolet disinfection system to kill remaining pathogens.Another example is the Oceanside Plant in San Francisco that treats a volume of 1.7 billion litres per day. For the filtration of about 1/1000th of that quantity a LM is utilised to meet the swimming pool water norms where it is reused, alongside the need for irrigation and areas of deficit. The portion treated by the LM showed that the effluent contains less than ten percent of the ammonium per litre treated by the rest of the system and this shows the workability and viability of the LM effluent. [49]

A great potential is predicted for the use of a LM in Third World Countries - on the residential level -for the reduction and prohibition of waterborne diseases transmitted through ineﬃcient treatment technologies, while beneﬁting from the generated by-products to close the economic gap in some areas, as in fertilizer purchasing costs. [47]

Operating principles

The working principle of the LM, that aﬀects the overall operating eﬃ- ciency is determined with multiple factors that are described in the following sections:

Functionality of a LM

The use of bacteria is the essential principle on which the employment of a LM is based on, Moreover the LM adopts and uses plants, gastropods and

Page 33 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings aquatic creatures that perform contaminants removal, mineralization and material stabilization; depending on the remediation stage. [50]

When dealing with pathogenic elimination and destruction in the wastewater, the first step is an anaerobic septic tank where anaerobic bacteria takes place to decompose and break down to the initial elements the organic content of the waste, this requires the preservation of a thermophilic environment that entails a specific temperature ranging from 55o to 65o C. as reported by Hauge, 132 .The operation of the septic tank in a LM treatment scheme is based on the concept of solid settlement and transfer of the supernatant to the closed anaerobic reactor. The reduction of the BOD5 at this step is made by increasing the oxidation rate of the waste, made by the installation of pumps for air blowing throughout the tank.In this tank the NH4 is converted into NO3 takes place, also known as nitrification.When dealing with a higher content of pollutants alternative configurations are in hand, such as the installment of an anoxic reactor that uses denitrifying organisms to further breakdown the reactions and convert the NO3 to N2 gas and ease its absorption by the plants or its release to the atmosphere [50]. The significance of the plants in the LM comes in them providing the habitat for the bacterial and microbial growth, the division of the microorganism into aerobic and anaerobic serves as an indication to the portion of the plants’ roots that they could inhibit, furthermore they influence and control the gaseous filtration and conduct some secondary cleansing to the water under treatment.Following that is the aerobic treatment unit that reflects the aes- thetical aspect of the LM and contains plants, snails and aquatic organisms that will work on the water cleansing, decomposition and act as a substrate for bacterial growth and sustainability.The flexibility of the LM design is a positive feature that allows- for a lack of a better expression- a chameleon feature that changes depending of the urban planning and climatic conditions, To elaborate some designs might incorporate clarifiers, constructed wetlands and ultraviolet disinfection units. The general system contains these basic stages: the anaerobic septic tank, the closed aerobic reactor and a series of the open aerobic tanks, eventually making up a system comprised of four or

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ﬁve stages and treatment ﬂows [50].

Maintenance of LM

Even with the existence of a general layout of the LMs, they differ in size (based on the processed water quantities), shape, number of treatment phases and additional treatment units. These requirements are tailored to fit the needs and the final uses of the treated water.

After the estimation of the flow to be treated, there should be a precise evaluation of the feasible installation space for the LM and the greenhouse in the case of colder regions (bearing in mind the elements to carry out sufficient photosynthesis for the plants and the optimal functioning of the bacteria used in the remediation). The maintenance of the LM includes the replacement of fallible mechanical components that make up the system as: pipes, pumps and emergency control valves to redirect the flow towards the municipal treatment infrastructure in the case of malfunction. The biological components are to be maintained through pest proliferation control, plant pruning and removal of harmful microbial eutrophication that damages the operating conditions. Maintenance is implemented usually by designated personnel that also manage the amount of feed to the systems does not fall below limits or exceed the peak flow rates of the design [50].

Driving Factors

The design criteria is based on trial and error, due to the rudimentary of the field of ecological engineering and design, while others were inspired from experiments and scientific efforts. It is pivotal to ensure that species are to survive within the confinement of the device itself as a mesocosm. A number of principles have been identified to reflect optimal ecological design and their level of importance, these factors include the following:

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• Wastewater type

The wastewater quality is deﬁned by a mineral composition that changes according to the origin of the wastewater.the mineral composition of the water is decompsed by the bacteria to form mineral/ organic compounds known as colloids, In the colloids the organic portion acts as a surface of the ionic exchange and is the dominating mechanism for the reactions that is only exceeded in the presence of photosynthesis and aerobic respiration [51] [52]. • Nutrients Availability

The mineral elements sometimes are difficult to attain in a short time and here comes the importance of nutrients when elements are recalcitrant, in- soluble or when the NPK ratios are insufficient. Otherwise the continuity of the ecosystem is threatened. On the LM scale it is vital to seal the nu- trient deficiencies -by the flora and fauna of the remediation system-using a supply of soluble forms of fertilizers to provide the short-term supplements to the ecological machine. The unavailability on nutients for sorption by the microorganism such as inorganic carbon, specifically for the nitrifying bacteria will cripple the nitrogen degradation and toxicity will increase with the ammonia rates increasing. This eventually leads to the shut down and disconnection of the biological pathways of decomposition. The additives that could be introduced could be from the treated sludge that is rich with nutrients or fertilizers as mentioned before for correction of the nutrients deficiency [53]. • Steep Gradients

Describes the properties and change whether rapid or sudden in the mesocosms as a function of space and time. This is demonstrated by variant oxygen regimes, pH levels, redox potentials, temperature and the organic and inorganic content of the sub-ecosystem (the use of a series of stages with diﬀerent values of the BOD, COD, TSS and TDS and the metal-related states to secure better results than a single stage stream).The process gradient is the attribute that connects these properties and reﬂects the feedback.

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In the tanks where there is a solid/ liquid separation due to gravitational force (supernatant and sediment settlement in the bottom of the tank, the gradient highly influences the redox potential that affects the settlement and the water properties, where the low redox potential increases the formation of hydrogen sulfide. [54]. • High Exchange Rate

One of the main targets the ecological machine is to maximize the surface area where the waste should be in direct contact and exposure to the treating mechanism (whether micro or macro species). It is of critical importance to secure the exchange surfaces and the associated treatment communities against perturbations to achieve consistent and reliable treatment eﬄuents.When it comes to LM one approach is using ﬂoating aquatic plants, where the roots are the exchange surface through which the microbial population is supported and being the media for liquids and air exchange [55].

the employment of diverse biological surfaces showed that higher exchange rates are attainable, specifically when using ecological fluidized beds, that is a subsequent treatment beyond the trickling filters or bio-filters contain controlled aquacultures. The use of the fluidized beds allows for higher exchange rates with plankton, small fish, higher plants, and moreover internal loop recycling with nitrification and denitrification depending on existence of oxygen and the organic carbon content [56]. • Periodic and Pulsed Exchanges

The intensity and periodicity holds high signiﬁcance in deﬁning the mode of treatment, without disregarding sudden and random events (such as ir- regular peak demands). As it has been stated direct reaction of organisms to environmental change is most useful if the environment is being altered in an unpredictable way. This parameters favor the notion that complex systems are to be replaced with simple systems, but with higher yield ranges.This disturbance is preferably applied at the initial stages of the system by introducing the abnormal-

Page 37 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings ities lightly to allow for the system to gain robustness. Some of the applied disturbances include variation in the light intensity and radiation, the intensity of the water ﬂow and the supplied aeration. This does not negate the failure that is associated with the system’s physical apparatus. [57] • Design and structure of the mesocosms

Using the cellular system is the basis for design and upscaling the concepts to fit the needs and design objectives of the LM for efficient energy gain, material use and thus savings. The initiation from the cell is due to its operation as an autonomous system capable of digestion, excretion, com- munication with surrounding systems, division, replication and molecular synthesis. The replication of the mesocosms in the LM to a cellular system comes as follows, the climatic conditions and the greenhouse effect create an envelope for the system. the cells are the treatment units of the system that are connected through piping so that one unit’s influent is the effluent of the prior unit, and the recirculated and recycled material act as a closed loop of feed and catalysts. To optimize the device cross linking the routes while preserving the input and output is made.By implementing the cellular design the living machine technologies can be controlled to adopt the needs for expansion and contraction through the addition or subtraction of the populations, these modifications are incorporated without disassembly or annihilation of sections of the apparatus [58]. • Fauna Diversity

It is apprehended that organisms from varying phylogenetic levels play different roles: starting from contaminant reduction to environmental destruction. this entails that rigorous research to ﬁnd ﬁtting species for ecological design is to be made. For the system to secure continuity useful endpoints are to be indicated for the following: environmental reformation, foods and fuel digestion and waste recovery. Since the animals used in LM have high sensitivity to the changes in their

Page 38 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings habitat, this usually serves as an indicator for the operator to increase or decrease the water recycling rates to minimize performance losses and conserve energy and to detect malfunctioning modes [59]. • Biological exchange with the natural systems

Gaseous, nutrients, mineral and biological connections with the existing natural system are used as optimisation and organization techniques for the living technology, in addition to pertaining proper remedial techniques against alien invasions and pathogenic manifestations. The base of the systems is made by a wide array of natural, polluted and humanly controlled ambiances, the endurance of the system undergoes a number of natural selection loops to reach the ﬁnal stable metabolic system. In the case of aquatic mesocosms, the selected species are preferred to be stream, pond and lake types that are more adapted to seasonal changes [60]. • Microcosm, Mesocosms and Macrocosm relationships

The key to successfuly design microcosms and mesocosms is simulating an macrocosms with intricate attention to regulatory survival drivers as temperature and pressure. For the biological and ecological sectors it is of utmost importance to merge different disciplines of complexity, exchange rates, dynamic forces and symbiosis. Interestingly a link between the LM and the natural ecosystem could be made for the biological material exchange, where a portion of the flow could be directed to the natural ecosystem (e.g pond) and flows back to the LM as a source of chemical and biological material exchange [56]. • Microbial communities

As microbes are an essential driving force and their communities can be optimized through diversiﬁcation of the micro-organisms and the ubiquity principle.The microbes included in wastewater treatment include bacteria, nucleated algae and slime molds, and protozoa with diverse metabolic requirements and nutritional habits [58]. A large portion of the metabolic reducing reactions and catalytic processes

Page 39 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings are governed by the bacteria with their wide array of degrading mechanisms that work on diverse materials and components. As for the removal of coliform bacteria, pathogens, and moribund is established by protozoa, which additionally improves the overall system eﬃciency [61]. As for the decomposition, fungi represent the leading decomposers with a number of approximately 100000 species and the ability to excrete enzymes.This enables them to remove and reduce the organic content from the wastewater, with a preference to acidic environments and thus recommends the inclusion of soils with lower pH values connected to the design of the treatment facility [62]. • Minimum number of mesocosms and microcosms

The number of the subecosystems controls the viability and operating feasibility of theLM to preserve and thrive in time, While the dependence and coupling between the microbial societies should be investigated and studied to secure symbiosis [63]. Investigation is made through empirical testing of the system dynamics, stability and self-regulation in a conﬁned ambient.Experiments illustrated the requirement for at least three sub-ecosystems : 1. Photosynthetically driven system that describes the plant and algal existence. 2. The zoological presence, usually contains the animal form of biomass (ﬁsh and snails..etc.). 3. The bacterial and microbial realm of the device.

When working with less than three ecosystems, it has shown that it is hardly possible to maintain the zooplankton and benthos, moreover the phy- toplankton percentages will be plummeting.The addition of other cells (rep- resenting the sub-ecosystems) leads to an enhancement the robustness and stability of the LM; due to pathogenic control and toxins reduction. Current ecological research doesn’t suggest an upper limit for the maximum number of treatment cells, but is evolving to integrate and cross over diﬀer- ent waste streams (e.g food/ﬁber and fuel production).

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A general rule for acceptable competence suggests three cells but favours four basic components for better cohesion and stability. These ecosystems are harnessed and connected by tanks and pipes that could be from metal, but the use of plastic and lightweight polymers is prefered to reduce the weight and the corrosion of the mechanical components and the disruption and discontinuity of the habitats [64].

System Design

The initial step in the treatment using a LM system the preliminary influent screening, afterwards the tailored design components based on the final characteristics and use of the wastewater define the treatment path and the need for additional processes such as ultraviolet disinfection units. The process scheme is explained through the following andthe possible layout of the system is well demonstrated using figure3.2:

Figure 3.2: Diagram of LM and its components,Source:Ochsendorf,Adams and Connor.Design for sustainability,MIT open course ware 1. Septic Tanks or closed anaerobic reactors: This is where the sewage collection takes place and the organic matter is broken down leading to the settlement of the reduced solid -through the oxygen free chemical reaction- that is eventually collected sludge and the liquid carries on

Page 41 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

to the subsequent unit. The main purpose of the anaerobic reactor is

to reduce the BOD5 concentrations. The septic tank resembles a primary sedimentation tank and by trap- ping and settling the solids it provides the surface area for the anaerobic bacteria colonization and accelerate the solids digestion. For the sludge accumulated in the bottom, they are periodically removed through per- forated piping and utilized afterwards for the designated design use such as organic fertilizers or feed to sludge feed microbial fuel cells.the odor emitted by the reactions is controled by the use of wither activated carbon ﬁlters or bioﬁlters [65].

2. Closed Aerobic Reactor: With the purpose of additional BOD5 removal and odorous gases. The odor control by the biofilter is made by locating it over the reactor directly where plants exist for the moisture level control. The aeration in the system that stimulates the nitrification is made by air diffusers that provide the portion of oxygen in decomposition reactions [65].

3. Open Aerobic Reactors: Consists a number of aerated tanks with the design similar to the closed aerobic tanks, but lacking being covered with the bioﬁlters and instead the coverage is made with rack supported vegetation that represents the surface area for the microbial growth

and provide the nutrients. The purpose is to reduce the BOD5 and complete the nitriﬁcation below the secondary levels [65].

4.Clarifier: For the residual solid to settle and separate from the water. The residual solid is recycled to the closed aerobic reactor, removed or sent to a holding tank where further treatment takes place. The surface of the clarifier can suffer from algal bloom, but this is avoided by covering the surface with duckweed [65].

6.Effluent Tanks: For the storage and collection of the treated effluent. It acts as the source for providing the water to its defined(recycled) use such as flushing toilets or pool water based on the design criteria and effluent properties [65].

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Advantages of LMs

The apparent advantage of a living machine over the conventional treatment is that the LM is aesthetically pleasing and attracts the public attention and involvement in the assimilation of greener technologies, It furthermore reuses and reduces the depletion of resources such as water and the use of purely organic fertilizer. It is beneﬁcial to be implemented in regions where there is strong public opposition to traditional treatment options and not disrupting the public appearance of the area.The system can reach the treatment characteristics as displayed in3.1: Table 3.1: Final removal limits in LM

Total Nitrogen 6 10 mg/l TSS 6 10 mg/l BOD5 6 10 mg/l Nitrate 6 5 mg/l Ammonia 6 1 mg/l Phosphorous 6 10 mg/l

Restrictions and Challenges:

1. Space Availability: The space for the installation represents the most precarious element.with the lack of space for the sludge and septic tank leachate that is intended to reintegrate in the soil and will eventually pile up and accumulate. This can be mitigated by incorporating sludge removal in the treatment or implementing a holding tank to control overflow, but requires a large amount of space. The feasibility then is mainly a trade off between the spatial decisions that will substantially influence the treatment [58]. 2. Light: Exposure to light and for long duration is necessary for the growth of the plants and the bacteria, moreover it plays a role in the temperature control of the tank. For cold area the construction of a greenhouse

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or a solarium is the solution to maintain the temperature at viable levels and maximize the radiation reaching the system [58]. 3. Plumbing: Generally the existing piping and plumbing will require replacement and rerouting. Where the initial effluent is obtained after decentralizing from the used infrastructure and directed towards the anaerobic septic tank, they also have to be adequately placed to grant gravitational flow with avoidance of overflow that would paralyze the performance. When it comes to the plumbing, the process is costly and time consuming when trying to allocate and determine the efficient and cost effective schemes for the wastewater to and from the LM, bearing in mind the LM machine cost is consider a significant initial investment in terms of construction and design, but will provide a future gain and preservation of resources and expenses [58]. 4. Flora and Fauna cost: The choice of the plants for the LM depends on the climate conditions and the availability of the species. The price range in the flora varies between 4.5 e to 6.5 e , but it could reach 10 e per unit for the deep-water plants the are more on the more expensive side. The monetary element requires a certain estimation of the volume of water and the area occupied by the machine to quantify the amount of the flora and fauna needed for the treatment [66] [58].

Maintenance:

Additional to the conventional wastewater treatment plant requirements of maintenance that are : 1- Vegetation pruning and thinning to maintain the microbial growth, the gaseous absorption made by the plants, clogging and the overall representation of the unit. This aids in the plant growth and the reduction of the foliage accumulation. 2- Cleaning the tanks and the screen from sludge and residues with proper disposal according to the regulatory limits. The refused sludge should go through a composting process to enable their use in horticultural and

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agricultural application or their transformation and the extraction of other source of energy such as biofuels or the use as a feed in Microbial Fuel Cells for electricity generation. 3- The fauna populations management and control with the inhibition of pesticides manifestation, and thus losing the purpose of the environ- mentally and ecologically acceptable system [58].

Page 45 4 Wastewater treatment using microbial fuel cells MFCs

Introduction

A microbial fuel cell is a device that converts the chemical energy in the chemical bonds of the organic compounds into exploitable electrical energy using biologically driven catalytic reactions that degrade and stabilize the organic matter -the feed to the cell - which explains their implementation in wastewater treatment plants. The MFC is highly sensitive to variations in the operating conditions, and hence are used as biosensors for the mea- surements and monitoring of DO. MFCs vary in the power generated and the Coulombic efficiency depending on the type of the microbes used in the anodic chamber of the device and concentration and type of feed and the total system configuration [67]. The conventional wastewater treatment systems used today show to be highly energy consuming and was approximated in the US to consume 0.349 kW h per cubic meter of wastewater when using an activated sludge treatment. This accounts for an annual lump sum of 21 billion kW h of electrical energy with undeniable negative environmental and energetic impacts, the installation of the conventional treatments in developing countries will result to a higher negative footprint as oppose to that imposed by developed counterparts [68] [67]. The burden of this energy requirement is embodied in the pumping and aeration processes of the treatment that are 21% and 30 — 55% respectively. But when comparing with the MFC, the MFC generates electrisity as oppose to consuming it and the bio-electricity generated is clas- sified as a source of renewable energy and meets the standards of the green evolution of energy [69].

46 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Progression and evolution:

The rudimental MFC design was initiated from a two-bottle electrochemical cell and moved towards a tubular bioreactor configuration [30] . The technology of the MFC generated considerable interests in the research community in the recent years by various academic researchers as (Allen and Bennetto, 1993; Gil et al., 2003; Moon et al., 2006; Choi et al., 2003) (Park and Zeikus, 2000; Oh and Logan., 2005) [70] [71] [72] [73] [74] [75]. The traditional configuration of the MFC consists of an anodic and cathodic chamber connected together through an ion exchange membrane. Due to scale-up complications, the use of a MFC was confined for a long duration to experimental and laboratory curiosities. Despite that the operating concept still remained attractive and unique that led to the design of several configurations to increase the generated power such as those by (Biffinger et al., 2007; Oh and Logan, 2006; Prasad et al., 2007 and (Cheng et al., 2004; Kim et al., 2007b; [76] [77] [78] [79], with each design using a different chemical catalyst. Initially the catalyst used were metallic ones such as P t and Au that were restrictive in scaling up the model since they are of high-cost for scaling up, and hence biocathodes and enzymes were tested as catalytic alternatives and gave promising results. some of the organisms used in biocathodes and mentioned in literature are ShewanellaoneidensisDSP 10 in pure culture [76]; T hiobacillusferrooxidans in artificial wastewater [78]; micro-algae in ocean environments, But the first promising use of MFCs in wastewater treatment was with the experimental success made by Liu et al.2004 using the municipal wastewater as a substrate in an air tight MFC, this approach facilitated the process of scaling up and possibly replacing conventional wastewater treatment systems and combining the wastewater treatment with power production. [80]

The working principle of the MFC is that the anode of the MFC oxidizes the substrates and releases carbon dioxide as an oxidation product, and pro-

Page 47 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Figure 4.1: Components of a typical MFCs and its working principle [30] duces electrons and protons in the process. The exerted carbon dioxide has no impact since its originated from a renewable sources (the biomass). The electrons and protons extraction is performed by the microbes using a dissim- ilative process. The continuity of the electric current generation is established by microbial separation from oxygen or any terminal acceptor diﬀerent from the anode since the anode is the anaerobic chamber [30] as demonstrated in ﬁgure 4.1.

MFCs Design

The main components of MFCs are illustrated in 4.1 and are described through various systems and operating configurations with the adequate application realm of the designated configuration and that trade-off between energy and waste digestion. Components

The typical design of an MFC is made by PEM, an anode and a cathode. This is illustrated in the table 4.1 along with the type of the materials suitable

Page 48 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings for each speciﬁc component and the necessity of the apparatus to the MFC and its operation. Table 4.1: MFC Components [15]

component importance material Proton Necessary Naﬂon, Ultrex, Polyethylene.poly exchange (styrene-co-divinylbenzene) for membrane the membrane. Salt bridge, porcelain septum or electrolyte. Anode Necessary Graphite, graphite felt, carbon paper, carbon-cloth, Pt, Pt black,RVC . Anodic Necessary Glass, polycarbonate, Plexiglas chamber Cathode Necessary Graphite, graphite felt, carbon paper, carbon-cloth, P t, P t black, RVC Cathodic Optional Glass, polycarbonate, Plexiglas chamber 3+ Electrode Optional P t, P t black, MnO2, F e +, catalyst polyaniline, electron mediator im- mobilized on the anode

Two- chamber MFC systems

The operation of this configuration is commonly in batch mode with acetate or glucose as an energy generating medium, but the application is currently confined to laboratories. It is composed of an anodic chamber, a cathodic chamber linked by a PEM or a salt bridge for the allowance of the proton mobility across the cathode and intercepting oxygen diffusion to the anode [15] . The assembly of the MFC can take different shapes as depicted in the figure 4.2 . The last configurations are the most adequate to use in wastewater treatment and are easy to scale-up, but the energy output of the systems is

Page 49 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings not suﬃcient in this case and its main function becomes wastewater treatment and sludge stabilization. The low energy content is caused by the proximity of the anode and cathode over a large PEM surface. The second represented arrangement where the anodic chamber is inoculated biomass, with dry air and is pumped to the cathodic chamber without the need for a liquid catholyte and this makes it possible to operate it in a continuous or a batch mode [15] [81]. Single-compartment MFC

The use of a single compartment MFC suffers from the complexity in scaling up the two compartment system. The basic design of the MFC is less costly with a composition of an anodic chamber and without the need for aeration in the cathodic chamber. The nomenclature ”single chamber” comes from the fact that the anode and cathode are housed in a single compartment. The single compartment MFC could be made up with eight graphite rods that are the anode surrounding the cathode [82] as shown in figure 4.3. Up-flow MFC

The MFC is fed from the bottom of the anode and the eﬄuent passes through the cathodic chamber where it exits from the top. a plexiglas cylin- der is divided by glass wool and glass bead layers serving as the anodic and cathodic chamber and a disk-shaped graphite felt anode and cathode. The operation is determined using the DO gradient provided by the diﬀusion barriers between the anode and the cathode [83] [84].

Stacked MFC

Described as multiple MFCs connected in parallel or in series; reaching better current output and voltage. When operating in parallel the efficiency is significantly higher than when operated in series with the same volumetric flow rate, but the stack in series has a lower short circuit current and a reverse diode is prevented that could lead to a power sink. If the objective is the power production then parallel stack arrangements are used and favored

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Figure 4.2: two-chamber MFC in five different configuration: (A) cylindrical shape, (B) rectangular shape, (C) miniature shape, (D) cylindrical upflow configuration, (E) Cylindrical U-shaped cathodic compartment. Adopted from Delaney et al., 1984; Allen and Bennetto, 1993; Ringeisen et al., 2006; He et al., 2005, 2006).

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Figure 4.3: cylindrical single compartment MFC with eight graphite rods (anode) surrounding the cathode. Source ((A) with modiﬁcations after Liu et al., 2004. (B) drawn to illustrate a photo in Liu et al., 2004.)

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Figure 4.4: vertical(A) and plan view (B) of up-ﬂow MFC. Source Jang et al., 2004; Tartakovsky and Guiot, 2006, respectively.

Page 53 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings instead of independent operation of MFC units.but the in series conﬁguration os to promote water treamtment along with electricity production.

MFC Operation

When referring to the functioning of a MFC a distinct distigntion is at place between ideal operating conditions and the actual one.Which are described more elaborately in the following: 1.Ideal MFC: Based on electrochemical reactions conducted at low potentials and with a high potential electron acceptor. The use of an ideal MFC carries some voltage uncertainty in the amount of electrons transferred from the organic matter (substrate) to the anode using a redox mediator providing the reduced substration and it differs by time depending on microbes and growth conditions from the reduced mediator [30] [85]. In case the MFC is mediator-less the anodophiles (the microbes) create a biofilm on the surface of the anode that is the final terminal electron acceptor for the anaerobic conditions. The anodic potential is estimated using the ratio of the final cytochrome of the chain in reduced and oxidized forms and the calculation of the ideal potentials is made by Nernst equation (equation4.1) giving ranges from a few hundred mV to over 1000 mV. The electrode reactions and their redox potentials used in MFCs as given in the ensuing 4.2 [86]:

θ Ecell = E cell − RT /zF ∗ lnQr (4.1)

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Table 4.2: Electrode reactions and corresponding redox potentials

Redox pairs Eo mV

O2/H2O +820 2 + NO 2/NH4 +440 3 4 F eCN −6/F eCN −6 +430 − − NO 3/NO 2 +421 Fe(III) NTA/ Fe (II) NTA +385 Fe(III) citrate / Fe (II) citrate +372

O2/H2O2 +275 Cytochrome c(F e3+)/ Cytochrome c (F e2+) +254 Ubiquinone ox/red +113 Fe(III) EDTA/ Fe(II) EDTA +96 Cytochrome b(F e3+)/ Cytochrome b(F e2+) +75 Thionine ox/red +64 F umarate2−/Succinate2− +31 Methylene blue ox/red +11 Humic substances ox/red -200 to +300 Pyocyanin ox/red -34 Menaquinione ox/red -75

FAD / F ADH2 -180 2,6-AQDS/2,6-AHQDS -184 P yruvate2− / Lactate2− -185 2 SO4 −/H2S -220 0 S /H2S -270 NAD+/NADH -320 + H /H2 -420

2.Actual MFC: Due to losses the actual cell potential is lower than the ideal one and the losses in the cell are described by the following in 4.2:

Vcell = Ecathode − |ηact,c + ηconc,c| − Eanode − |ηact,a + ηconc,a| − iRi (4.2)

In the case of slow reaction kinetics the activation polarization is a limiting

Page 55 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings factor as it depends on an activation energy to be exceeded by the microbial organisms. If the microbes do not readily release the electrons to the anode then mediators are added to reach the required energy, as for mediator-less MFCs the activation polarization is minimized due to the conducting pili. The calibration between cathodic material is made as the use of P t has a lower energy barrier to overcome as oppose to the use of a graphite cathode. The significance of the activation polarization increases with low current density as the anode and cathode need to overcome them in order for the flow of the ions to take place [87]. The concentration polarization loss is related to the inability to sustain the initial substrate concentration caused by mass transfer rates of reactants and products, this is treated by increasing the mass transfer through stirring and/or bubbling often made by pumps. To evaluate the effect of the losses in the overall potential decrease a polarization analysis curve is made that could indicate the measures of mitigations as enhancing the electrode structures, better the electro-catalysts, using conductive electrolytes and minimizing the spacing between the electrodes. The ohmic loss in the electrolytes is avoided by shortening the spacing the electrode while increasing the ionic conductivity of the electrolytes for the purpose of this study the reviewed MFC configurations that were assessed are the ones working with municipal waste water and are explained in the chapter of the analysis [88].

Factors Aﬀecting MFC performance

1. Electricity generating microbial communities: The MFC is governed by the perturbation and the uncertainty of the microbial organisms responsible of the electricity production, this translate in the minimal interference after the inoculation by the speciﬁc species and the headlining of the ecological evolution of the community in the inoculum and the species dominance. Usually the understanding of such biologically evolving systems is made by empirical evidence through trial and error and natural selection.a promising approach used in the

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past decades for informative results is the use of molecular methods, in which the biofilm exhibits phylogenetic diversity symptoms with syner- gistic degradation of compounds. The evidence showed no dominance by a specific electrogen species and that the increasing phylogenetic diversity in the anode biofilms is proportionally linked to functional diversity that permits coexisting taxa to transfer electrons to the anode electrode [89] [90]. The increase the optimization of the system the use of mixed cultures is beneficial with the added advantage of substrate flexibility, and the population will be more robust to environmental disturbances and able to endure changes in the metabolic pathways such as changes in temperature, organic loading rate,etc. The microbial diversity in the MFCs communities is utilized for the derivation of applicable design that as reliable, this is tested using various methods as high-throughput sequencing that gives details on the cuts across the biological waste treatment technologies and comparing the obtained models of community formation with their sensitivity analysis [91]. 2.Anodic chamber operating conditions: In a MFC the power varies and depends on the microbial consortium, concentration and the feed rate, this is also highly related to the operation mode whether it is batch or continuous. The higher the concentration of the fuel is the higher the yields for the power output and the higher the power density output is [92]. The electricity production reaches a peak value initially with a low level of feed rate before it plummets this is due to the faster growth rates of fermentative bacteria when compared to the electrochemically active ones in a mixed culture. The microbes growing as biofilms are rarely affected by the increasing fluctuation in the feed rate since it presents competing electron acceptors at the anode to lower the output [93]. 3.Cathodic chamber operating conditions: The power produced is inextricably linked to the concentration of the electron acceptors, and most commonly oxygen. And the DO becomes a limiting factor when the air is below the saturation levels as proved that a 38 mg/l DO doesn’t increase the power generated when compared to a 7.9mg/l DO

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with saturated air conditions [81]. The DO levels strongly control the rate of oxygen diffusion as the substrate is consumed by the oxygen and not transferring electrons to the circuit. The power outputs in the cathode increase when the electron acceptor has a lower activation energy for the cathodic reaction [83]. 4.Proton exchange system: As mentioned before the proton exchange system creates concentration polarization losses and internal resistances that lower the power output of the cell, with the Naflon being the most used material despite the cost and the unavoidable cation transport, this causes the transportation of Na, K, NH4, Ca and Mg to be at higher concentration compared to the proton in the anolyte and catholyte [94]. Moreover the PEM’s surface area controls the power output as the internal resistance decreases with the increase of the surface area [77]. 5. pH buffer and electrolyte: The buffer solution is used to regulate the pH levels in the MFC and balance the pH between the anodic and cathodic chambers, specially when the production rate of the protons at the anode varies from the reaction rate of protons, electrons and oxygen at the cathode. The pH difference comes from the protons crossing through the diffusion membrane at a rate slower than production rate at the anode and the consumption rate in the cathode at preliminary MFC operation stages. The variations in the pH are a driving force for the proton diffusion from the anode to the cathode chamber reaching dynamic equilibrium conditions. The protons generated are divided into a portion capable of reacting with the DO and the other portion accumulate in the anodic chamber when and do not transfer fast to the cathodic chamber through PEM or the salt bridge. The use of a buffer solution also compensates for the slow transport rate and increases the proton availability for the cathodic reaction [93] [95]. 6. Type of electrode material: The use of different material as electrodes gives different activation polarization losses and this results in different performances by the MFC. The electrode giving the highest potentials and density is the use of P tand P t black followed by graphite, graphite felt and carbon cloth electrodes. Even though the activity of P t or P t

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black is reduced by the formation of a layer of P tO on the electrode surface at positive potentials. Electrode modiﬁcation and enhancements are made to improve the potentials such as P t- coating, NR-woven graphite and Mn(IV) graphite anode as oppose to using woven graphite anode alone. For cathodic reactions the use of Fe(III) and/or Mn(IV) catalyzes the process and improves the power generation [96].

Beneﬁts of using MFCs:

1.Wastewater treatment The municipal wastewater is composed of large multitudes of organic compounds that are suitable as MFC feed. The use of this feed in the electricity generation has the potential of lowering the power demand of a conventional wastewater treatment to 50% and with a 50 — 90 % less solids for the final disposal. The microbes used in the MFC increase the operational stabilization caused by their bioelectrochemical features.The use of swine wastewater, sanitary wastes, food processing wastewater and com stover that are rich in organic matter showed to be compatible with MFC in the previously mentioned configurations4.2 such as continuous flow, single-compartment and membrane-less MFCs that are easily scaled up to meet the quantities of the feed , where 80% of the COD was removed and an 80% Coulombic efficiency was reached [75]. 2.Sludge and biomass reduction The use of activated sludge treatment system produces large quantities of biomass that are to be disposed as sludge at designated locations. The management of the sludge appears to be financially exhaustive and energy consuming that in some cases it could reach 60% of the total operating cost. Using the MFCs reduces the biomass yield in levels that are more impressive than those obtained with other technologies using the technique of fixing the biomass to a surface [93]. The most commonly used microorganisms as a MFC biofilm are the Geobac-

Page 59 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings ter and Shewanella. These families of bacteria give a cell yield of 0.05 to 0.27 g biomass COD/g substrate even though the yield could exceed this value depending on the type of reactor and the external resistance load. For this reason, an increase in the sludge retention with lesser biomass production are adding to the power generation with the suitable design and operating strategies and thedesign made by is a viable example as it uses concentrated black water(high content of fecal matter) as the feed to the cell (described in the analysis chapter) [32] [30]. 3. Effluent treatment process Acids such as acetate and butyrate are consumed by a MFC even at low concentrations where the MFC plays the role of a biosensor detecting the levels of the organic contaminants and a gauge for the desired endpoint effluent standards. The attachment of a MFC after an anaerobic treatment process lowers the accumulation of the by-products and further purification for the discharge, and to reach a much sustainable approach the coupling of a MFCs with AD and bio-hydrogen (Bio- H2) strengthens the total recoverable energy [97]. The optimization of the organic matter removal is controlled by the operating temperature even though the MFC could operate under ambient conditions the temperature range of 30 — 50oC give the best power and organic matter removal outcomes. Observations for the balance between the removed organic portion and the electricity generation could be an indicator for an increase in the activity of the methanogens when the removal rate is increased but the power production is reduced. To sustain the preferred temperature energy could be added to the MFCs, but without exceeding the energy produced and should be assessed using energy balance equations not to negate the purpose of using the MFC [98]. 4.Electricity and biohydrogen production The chemical energy in the bonds of the organic feed are converted into chemical energy and transformed to electricity with the microorganisms avoiding the intermediate thermal energy transformation (avoiding the limited efficiency of a Carnot cycle) and achieving a >70% conversion efficiency meeting that of a conventional chemical fuel cell [99].an exampe of the power den-

Page 60 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings sitiesfrom industrial and domestion wastewater range from 4 to 15 W/m3 (Cheng et al., 2006; Feng et al., 2008; Liu and Logan,2004) [100] [101] [82]. MFCs could be modified to produce hydrogen instead electricity. Where the protons and electrons produced by the anodic reaction are combined at the cathode and produce hydrogen. For the biohydrogen production the presence of oxygen in the cathodic chamber is not required and hence the overall efficiency is improved since the seepage of oxygen to the anodic chamber does not occur. When it comes to hydrogen production one of the biggest limiting factors is the difficulty of storage which is surpassed since it could be stored and accumulated in the cell itself, providing a renewable hydrogen source that could be commercialized [102].

Page 61 5 Sewage Treatment by Vermi- ﬁltration and Earthworms’ sludge digestion

Introduction

Vermifiltration is the process that combines filtrations techniques with vermicomposting in the treatment of wastewater that represents an eco-friendly and cost effective form of treatment [103].

The vermifiltration of the municipal wastewater can be achieved through the biodegradation carried by an earthworm’s body that resembles the work of a biofilter. The earthworms have the capability to remove approximately over 90% of the BOD5 , 80 — 90 % of the COD, 90 — 92% of the TDS and 90 — 95 % of the TSS by the biodegradation and decomposition of the organic matter content and inorganic content of the wastewater, with avoidance to sludge formation and thus eliminating landfill disposal. The proliferation of the worms in the confined area does not represent a problen since the layer containing the worm is reduced after a specified period of time as it serves as a fertilizer.A main advantage is that the process is free of gaseous emissions and odorous escapes which negates the use of gas treatment units, the earthworms act as inhibitors for the commencement of the anaerobic microbial reactions that have a final product of foul gases releases as hydrogen sulfide and mercaptans. [17]

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Characteristics of Earthworms

Earthworms are boneless, cylindrical, bilaterally symmetrical species. They are dark brown and covered with a thin cuticle layer. The average weight of an adult worm is 1400 — 1500 mg ( at 8 — 10 weeks). They have a 3 — 7 years life span. Earthworms harness a tremendous amount of nitrogen ﬁxing components and decomposers in their intestines with chemoreceptors to ease the food detection and search. The body mass is composed of 65% high quality protein, 14% fats, 14% carbohydrates and 3% ash. [104] [105]

Earthworms are distinguished among other species by: 1. Reproduction rates with rapid multiplication

They are classiﬁed as bisexual animals with a rapid multiplication rate, where each worm produces 3 cocoons on a weekly basis and with each cocoon containing 10 — 12 worms, the doubling of the population requires 60 — 70 days under the optimal surrounding conditions of moisture, temperature and nutrients. Each worm is estimated to give an oﬀspring of 300 — 400 within its entire life, assuming the reproductive capability is reached within 8 — 12 weeks from the hatching for brown worms and 4 — 6 weeks for red worms. [104] [106] 2. Sensitivity to light, touch and lack of moisture

Earthworms are highly sensitive to high temperature and it controls their survival, while cold temperatures reduce their activity. They are also very sensitive to light and live in the dark. Their presence in odor oﬀensive environments is not harmful for their perseverance, as with time they kill the odor generating anaerobic and pathogenic organisms. [17] 3. Ecological adaptation and survival in harsh environments

The distribution and mobility of the worms in the soil is through the formation of tunnels while simultaneously feeding on the nutrients. The distribution is governed by bioavailability, pH and soil temperature. Their survival is

Page 63 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings scarce in coarse texture and clayey soil or those with pH 64 [107].They have low tolerance for salinity in soil, except for tiger worms (Eisenia fetida) that are highly tolerant to salt, that could reach a concentration of 15g salt/kg of soil with a survival percentage of 80 — 100% [108].Earthworms hold a tolerance to toxic chemicals such as TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and they bioaccumulate the dioxin in their tissues and concentrate it to 14.5 fold [109].Crude worms (tiger worms) additionally tolerate 1.5% heavy metals with a bioaccumulation that could reach 7600 mg of lead (Pb) / g of dry weight of their tissues [110]. The optimal survival condition for the earthworms is at a temperature in the range 22 − 25oC, but they have tolerance to 5 − 29oC, moisture content of 60 —75% although they could function in dehydrated environments while carrying ventilation through their skin and this requires air in the soil [106]. 4.Worm dynamics and functionality in sewage vermiﬁltration

Earthworms are decomposers of wide and versatile types of waste along with their support to decomposing bacteria that perform the numerous mechanisms in waste decomposition, starting from aeration, grinding, crushing, chemical degradation and biological degradation [111] [112].

The vermifiltration is composed of two synchronous processes that are the microbial process and the vermi-process. The improvement of the soil aeration through the earthworms’ mobility increases and accelerates the microbial activity in the soil,and thus the organic matter breakdown. The excretion of the earthworms produce decomposers known as vermicast, nitrogen and phosphorus, the latter two become a sources of nutrients for the microbial population and the decomposers which results in their multiplication and reproduction.With their ability to support a high specific area, they are able to capture the TSS on the top of the vermifilter and feed them to the soil microbes, while limiting to the TSS0s mobility [113] [114] [115]

As for the organic and inorganic content in the soil, the earthworms - through the process of complex biodegradation - trap these fractions by ad-

Page 64 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings sorption and stabilization. Using the process of clay granulation (increasing the hydraulic conductivity) the organic loading is further concentrated by the earthworms, Moreover they reduce the particle sizing in sand and silt which gives a higher speciﬁc surface area and develops adsorption of the organic and inorganic matter in the wastewater [116].

Critical factors inﬂuencing sewage vermiﬁltra- tion

The treatment through vermiﬁlteration is controlled by several factors controlling the proliferation and productivity of the Earthworms. 1. Hydraulic retention time HRT

It is described as the residence time of the wastewater in the worm inhabited soil profile. The HRT should be long enough for the vermifiltration process to take place. It depends on the type of soil, volume and thickness of soil, the number of adult worms per unit area. and wastewater flow rate. HRT defines the period at which the earthworms break down the wastewater to feed on the organic matter content alongside with the reduction of TDS, TSS, BOD and COD.The efficiency of the system increases with the length of the HRT to a certain degree; implying greater contact between the wastewater and the earthworms, hence greater removal and digestion rates. The maximum HRT would result in a slower wastewater discharge from the soil profile and slower percolation to the bed. HRT of the vermifiltration system is calculated as:

HRT = (φ ∗ Vs)/Q (5.1) 2. Hydraulic loading rate HLR The HLR is the amount of wastewater that a given vermiﬁltration system can treat. It is controlled by the volume of the wastewater applied per unit area per unit time, the population of the adult earthworms and the size and health of the worms. It is assessed using equation 6.3:

HLR = Vwastewater/(A ∗ t) (5.2)

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The greater the HLR is the longer the HRT is and the lesser is the treatment eﬃciency. The soil inﬁltration rates are a controlling factor that depend on the wastewater seepage velocity through the soil medium, and it relies on the soil texture, particle size distribution, bulk density and soil mineralogy.

For this precise form of treatment the sewage used is characterized by a

99% water content, 1% SS, high values of BOD5, COD, OC, while the DO is highly depleted. The wastewater is rich in nitrogen, phosphorus, heavy metals, coliform bacteria and TSS. adopting the limits described in the study made by R. K.Sinha et.al 2008 These parameters are usually found in the subsequent ranges with variations controlled by the area to be treated, the ﬂow rate and the monsoonal seasons [17]:

• BOD5 200 — 400 mg/l. • COD 116 — 285 mg/l. • TSS 300 — 350 mg/l. • pH 6.9 — 7.3.

As for the treated wastewater the values obtained are:

• BOD5 1 — 15 mg/l. • COD 60 — 70 mg/l. • TSS 20 — 30 mg/l. • pH ranging at the neutral level of 7.0. [17]

The sizing of the system is an important parameter in practical application, and this is due to the fact that the depth of the system is approximately fixed,while the surface area is made to accommodate the influent to match the HRT and HRL. The general depiction of the vermifilter layers is described as made by krishnasamy et al. 2013 [16].

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Table 5.1: Vermiﬁlter, Source:Vermiﬁltration systems for liquid waste management: a review [16]

Thickness of vermicast (layer 20-30 cm with worms) Sand layer(medium 0.25-0.5mm) 10 cm Gravel ﬁne(4-8mm) 7cm Gravel medium(8-16mm) 7cm Gravel large(16-32mm) 7cm clay liner (0.98-3.9 µm) 3cm PCC(plain cement concrete) 3 cm

The advantages of vermiﬁltration technology over conventional wastewater treatment systems

The use of vermiﬁltration over conventional wastewater treatment systems represents a calibration between the energy and cost balances, that could be summarized in: 1. Low energy and high removal rate

The use of the vermifiltration when compared to the conventional treatment systems of activated sludge process, rotating biological contactors or trickling filters, shows a lower energy consumption and higher energetic savings. Conventional treatment systems are known for their high installation and operation costs with no income generation from the treatment process. The use of a limited retention time in these systems gives a complex sludge that is saturated with organic material and heavy metals that must undergo a form of treatment before the final disposal. With the vermifiltration the entire quantity of the organic materials is captured with the final product having a high added value (vermicompost). Since the vermifiltration process operates with the use of the gravitational forces the only expensive energy

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Figure 5.1: Comparative results of vermifiltered and controlled kit [31] for (1) TSS (2)Turbidity (3) BOD (4)COD cost would be assigned to the pumping of the wastewater to the vermifilter An evaluation was carried out by Sinha et al. [31]. that is represented in figure 5.1 and the accompanying appendix .1 at the end of this chapter. 2. Pathogen removing system

The ingestion of pathogens represents the food for the earthworms. The worms exert a coelomic ﬂuid which holds antiseptic qualities and prevents from the formation of microbes again. The decomposers and other forms of bacteria and fungi living in symbiosis - within the worms - generate antibiotics and kill the pathogenic organisms in the waste and prevent the formation of biofouling. Evidence show that the pathogen removal rates are more rapid than their reproduction. [112] [117] 3. Simultaneous wastewater treatment and sludge stabilization

The earthworms ingestion of nutrients works as a sludge digester by the grume excretion with their strong mouth muscles and then the organics and inorganics are stabilized in the esophagus through calcium neutralization,

Page 68 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings moving towards the intestine for enzymatic absorption and decomposition the exerted material acts as a beneﬁcial agricultural and horticultural fertilizer. [118] 4. Vermiﬁlter as an odorless system

The aerobic conditions created in the soil by the worms, inhibit the action of the anaerobic microorganisms that create and release foul odors gases as hydrogen sulﬁde and mercaptans. Furthermore they capture and control the decay and decomposition of the putrescible content in the wastewater and the formed sludge. [119] 5.The use of Vermicast as a fertilizer

The existence of earthworms in the soil improves its fertility acting as a live biofertilizer. The excreta known as the vermicast that is in the bed of the vermiﬁlter is rich with nutrients that support plants’ growth from high concentrations of nitrogen, phosphorus, potassium. The earthworms also deposit proteins, polysaccharides and other compounds. [119] 6. wastewater is chemically intoxic

The bioaccumulation carried out traps the toxic chemicals and heavy metals and making them non-bioavailable. The earthworms are known to bioaccumulate Cd, Hg, P b, Cu, Mn, Ca, F e, Zn. As addressed and proved by Markman et al (2007) [120] that the earthworms can bioaccumulate the endocrine disrupting chemicals EDCs in their tissues that cannot be removed by conventional sewage treatment systems-but with reverse osmosis that is highly cost eﬀective and would impose a large economic load on developing countries. They also hold the capacity of degrading the organochlorine pesticides and the PAHs. [121] 7. Probiotic and protein-rich production of worm biomass

With the availability of the appropriate living conditions of the worms (food availability through the waste, moisture content temperature, etc.) large amount of biomass (worm meal) that is rich in nutrients and most

Page 69 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings importantly protein will be produced that could be used as feed for cattle, poultry and ﬁsheries. [17]. 8. Vermiﬁltration technology

The use of earthworms surpasses other treatments of bio-conversion and bio-degradation in that it uses portions of the waste that are usually dis- carded and not manageable in other forms of treatment with the utilization of the greatest magnitude of the materials embedded in the waste. The application of enzymatically driven reactions as biologically catalyzed chemical reactions increase the rapidity of the treatment [122] [17]. 9. Economic value

The supply of earthworms is a one-time cost as they multiply and improve the dynamics and the treatment efficiency of the vermiculture technology. The use of this technique gives useful byproducts and neutral water to be used in gardening, toilets’ flushing, floor washing, etc. And the nutrients in the water are suitable for irrigation. The biomass reduces the need for chemical fertilizers to an extent [17]. 10. Experimental Evidence/Griffith University Experiment A valuable representation on vermifiltration is the one carried out in a vermiculture kit in Griffith University. The lab temperature was held at 21.5o C with a 50% moisture content in a vermifilter kit. The kit contained 30 — 40 kg of gravel with a top layer of garden soil. after the vermifilter the treated water is collected at the bottom of the chamber through a tap fitted pipe. The bottom of the kit is layers with 7.5 cm gravel at 25 cm thickness, overtopped with a 3.5 —4.5 cm aggregate layer with the same thickness that is topped with a mixed layer of sands and 10 — 12 mm sized aggregated at 20 cm thickness. The population of worm in the system was estimated at start by 500 worms per 0.025 m3of soil and reaches 20,000 worms per m3 of soil. The pilot test was made in comparison with the same design of the kit in the absence of earthworms where the filtration of the wastewater is performed by the sand and the aggregates and the decomposition is through the microbes present in that setting, describing the system as a geological

Page 70 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings microbial system. Both kits (with worms and the control kit)were fed with 6 liters of municipal wastewater that hold the following characteristics and with a capacity of 40 - 45 kg of soil : Table 5.2: Municipal wastewater characteristics [17]

Parameter Value (mg/l) BOD 405.1 COD 522 TSS 160.2 Turbidity 180.1

The trend of the removal rate is well illustrated in figure 5.1 that also shows the number of experiments held to obtain proper calibration results. other observations were made for some symptoms like foul odor, wastewater percolation through the soil bed and its appearance and most importantly the earthworm population, the kit containing the earthworm showed no fouling as opposed to the control kit. Percolation through vermifilter has been more smooth and the control kit showed continuous clogging. The use of the vermifilter of the vermifilter generated in a pH neutralization. The use of the earthworms for the sewage removes the TSS by 90%, on the contrary the control kit removed 58% of the TSS with the periodical chok- ing of the system. For the turbidity removal the two systems were neck to neck with 97% for the control kit and 98% for the kit with earthworms. The

BOD5 removal rates for the worm inhabited kit was 98% or complete with a HRT of 1-2 hours caused by the enzymatic reactions, while it reached 77% in the control kit. The COD removal rates reached 45% in the earthworm kit and 18% in the control kit [31].

Page 71 6 Analysis: Case studies

Introduction

The previously introduced biotreatment technologies application will be applied to a hypothetical but realistic urban and domestic plan and illustrated with a scheme describing the final effluents and their reuse, where a calibration and trade off will be investigated between whether to advocate for resources saving (water recirculation) or energy production.

The case studies have been divided as follows to accommodate for real life living configurations: 1.Water’ streams division: in this case the output of the residential wastewater was divided into different streams depending on the water characteristics. 2.Installation of a LM: the incorporation of a LM as the main driver for the wastewater treatment, leading to the ellimination of the use of chemicals and solely relying on the biological processes carried out by the organisms used in the system was rendered most suitable to apply in multiple housing plans as apartment complexes. 3.Utilization of a MFC: aMFC is used to off set partially of the electricity consumption in the designated analysis unit. this is adequate to be implemented in single and multiple dwellings as it is not as costly as the use of a LM for a single housing unit. 4.Construction of a Vermifilter: this is considered to be applied for single dwellings since the design of the surface area of the vermifilter increases proportionally with the size of water to be treated and is not suitable in areas where buildings are situated in close proximity to each other.

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All four case studies were designed based on the worst case scenario (wcs)that accounts for the most exhaustive wastewater production for the unit under consideration. Additionally as a choice for furture development the ﬁnal ef- ﬂuent of all cases goes through a UV disinfection unit since it complies with the concept of no waste and residual material production entailing added waste. The characteristics of the water were made in reference to Crites and Tchobanoglous [18]as reported in table 6.1. Table 6.1: Composition of untreated domestic wastewater [18]

Concentration(mg/l) Measure Low Medium High TDS 270 500 850 TSS 120 210 400 COD 250 430 800

BOD5 110 190 400

Water’ Streams Division

General Assumptions

The building layout is represented in the table 6.2: Table 6.2: Building characteristics [19] [20]

No. of Apartments 4 per ﬂoor No. of Floors 6 Capita/apartment 5 Area of apartment 95 m2 Area of House 242m2 Surface area of Build- 4000 m2 ing

The ﬁrst approach is made based on substituting one appliance without the need to severely modify the building’s output and it is useful to be im-

Page 73 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings plemented in already existing buildings and does not require severe modiﬁca- tions to the existing system of wastewater collection. This is made through the installation of a urine diversing unit UD as a stream separation technique, hence the calculations and inputs demonstrated in table 6.3 to ﬁnd the amount of water consumed for urine and based on that the amount that would be saved using a UD system:

Table 6.3: Data about the urination [21] [22]

Urine production 0.8-1.5 Lpcd No. of time an adult 5-7 time/day urinates/day water consumed in 3.03 l/ﬂush ﬂushing

The maximum limits were adopted for the calculations and the values were multiplied by the number of residents per apartment times the number of apartments per floor times the number of floors to find the overall water consumed and the following was obtained as in table 6.4.

Table 6.4: calculation of urination and its water consumption

Urine produced in the 0.18 m3/day buidling Water produced for 0.0212 m3/capita/day ﬂushing water in building for 2.54 m3/day ﬂushing Total water 2.72 m3/day

As for the fecal matter the representative quantities are computed according to the average adult with a balanced diet [23] as reported in table 6.5 :

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Table 6.5: Data about the defecation [23]

Wet weight 128 g/capita/day Dry weight 29 g/capita/day water consumed in 6.06 l/flush ﬂushing No. of time for defe- 2 ﬂush/capita cation Total water consumed 1.469 m3/day for feces

Comparing these results to the ones in ﬁgure1.3 as reported by Bijl et al.2016.It is found that the incorporation of a urine diversion system lowers the water consumption for a toilet from 14.4 m3/day (about 24%) to 10.207 m3/day that results in a water saving of about 17 % . assuming the ﬂowrate per apartment in a centralized residential system is 0.5 m3/capita/day leading to a total of 48m3/day in the entire building [27]. Rainwater harvesting and outdoor usage The rainfall data used in this section are based on the meteorological data of the city of Milano adopted from timeanddate.com estimations for 2017 and the FAO assumptions with a average precipitation of 22 mm and an estimation of a wcs to be in April and to account for 38.3 mm used as the boundary condition for the design of the rainfall water harvesting system. The rainwater estimation is reported in table6.9 and selection of the storage tank is made on these calculations:

Rainflowrate = Gained precipitation ∗ (1 − Rainfall losses) ∗ Building surface area (6.1)

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Table 6.6: Rainfall Estimation

Rainfall 0.15 due to surface losses wetting and other factors gained pre- 32.555 mm/day cipitation Volume of 130.22 m3/day water per day

This amount of rain water requires an underground or ground installation of a plastic water storage that is resistant to harsh conditions and is anti- corrosive. The decision of the ground or underground positioning is not to increase the burden of an imposed load to the building structure. the outdoor water consumptions were made to meet the inputs in table 6.2 [19]:

Table 6.7: Outdoor water Estimation [19]

Plant Demand 1.37 m3/day Lawn Demand 0.89 m3/day Vehicle washing demand 0.31 m3/day per vehicle Outdoor water 2.57 m3/day

The use of a rainfall harvesting system in the building would compensate for about 51 times of the full load outdoor water uses in the residential building. Grey water Estimation The grey water is used to describe the sewage water ﬂow from washing machines, bathroom sink and rest of the streams depicted in ﬁgure 6.3, excluding the toilet water that has been previously separated,this is depicted in table 6.8 were 1 gpm (gallon per minute) = 6.55 m3/day.

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Table 6.8: Grey water Estimation [21]

Source gpm m3/day actual water use Entire m3/apartment/day building Kitchen sink 3 19.64 1.228 29.46 Bathroom sink 2 13.09 0.182 4.36 Tub faucet 5 32.73 0.341 8.183 shower headwith no 6 39.28 1.637 39.28 ﬂow restriction gallons per m3 per load m3/apartment/day load front loading wash- 27 0.1022 0.307 7.36 ing machine eﬃcient dishwasher 4.5 0.017 0.017 0.41 the total esti- 3.71 89.05 mate of water LM

The calculations for one apartment are based on various assumptions such as the running time for the kitchen sink throughout the day was made to be an hour and a half,for the bathroom sink it was assumed to have 20 seconds/wash that add up to 0.35 hours. The bathroom time for showering was averaged to reach 10 minutes per person and adding a marginal error time of an additional 10 minutes. In the case of a bath time is was estimated that one person would use the tub faucet and the running water time for ﬁlling to be maximized to reach 15 minutes.The grey water characteristics in the stream division holds the parameter values described in table 6.9and the assumptions made by Bijl et al.2016 [27] as shown in ﬁgure 6.1. Table 6.9: Grey water characteristics [24] [25]

Characteristic Range wcs

BOD5 (mg/l) 125-250 250 COD(mg/l) 250-430 430 TSS (mg/l) 50-150 150

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It is clear that taking a simple precautionary measure of changing one device will lead to a signiﬁcant reduction in the water consumption and the overall cost related to water when comparing the results in table 6.9 and the assumptons made by

Figure 6.1: Water Saving Results with UD

After the division of the wastewater into streams it is suggested that the continuation of the efflunent treatment is to be carried out using a LM that shows to be the most suitable form of biological treatment to be ustilized in the proposed urban multi-residential unit system with final effluent values from the device reported in table 6.10: Table 6.10: Final Effluent from LM adopted from (Living Machines, Inc., 2001).

BOD5 ≤ 10mg/l COD ≤ 10mg/l TSS ≤ 10mg/l

This is expressed in ﬁgure 6.2 that shows the treatment made by the LM

Page 78 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings demonstrates the removal rates of the characteristics as:

Figure 6.2: final effluents from the ue of the LM The HRT of the LM is based on the estimates adopted from Ecological design applied by Todd et. al were a calibration was carried to estimate the HRT of 7 days and the space occupied by the LM to fit within the system surface area (about 3/4 of the total area) and could be located in the service and utility floor and this plan is illustrated in figure 6.3.

Page 79 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings Figure 6.3: Schematic of stream division/LM system in an apartment building

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Vermiﬁltration

The design of the vermifiltration system is more feasible for decentralised and single housing units, and is applied here for the wastewater generated in a dwelling situated in a rural area since it is more fitting for rural areas with less population density per m2 and it translates into a higher surface area occupation. The design has been made upon the assumption of a single apartment (same number of residents) in the previously analysed stream separation system but as a stand alone unit. and the amount of water produced in this case is defined as blackwater.The water usage hence has been computed in table 6.11. Design of the Vermifilter Table 6.12: Vermifilter, Source:Vermifiltration systems for liquid waste management: a review [16]

The gravel layers are arranged with diﬀerent sizes starting from small at the top and increasing with depth,the calculation for the porosity was made with the upper and lower limits for each layer to ﬁnd the porosity accounting for the maximum surface area. The minimum porosity referred to as fmin was

0.51 and fmax is 0.64,afterwards to ensure that the HRT corresponds to the limit of 1 to 2 hours with both the estimates of the porosity.The calculation of the HRL was made following the approximation previously demonstrated in chapter 5 and are re-written in equation6.2 and6.3 and with the results of the calculations illustrated in tables 6.14 and 6.13.

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Table 6.11: Water use [21] [19]

Appliance Water use m3/day assumption Clothes washer 27 gallons per load 0.306618 3 loads per day (front Loading) dishwasher (effi- 4.5 gallons per load 0.0170344 1 load per day cient) Kitchen sink 3 gallons per minutes 1.2275 max. water usage is an hour and a half Bathroom sink 2 gallons per minute 0.1818 20 seconds washing time tub faucet 5 gallons per minute 0.35 15 minutes of filling shower head (no 6 gallons per minute 2.3186 10 minutes dura- flow restriction) tion with added marginal error Toilet flush(low 1.6 gallons(feces)- 0.14 the max numbers in flush) 0.8 gallons per 1 flush(urine) Plant Demand 0.057 [19] Lawn Demand 0.04 [19] Vehicle washing 5 gallons per minute 0.34 15 minutes dura- demand tion over all 4.87 over all m3/hr 0.203

Page 82 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

HRT = (φ ∗ Vs)/Q (6.2)

HRL = Vwastewater/(A ∗ t) (6.3)

Table 6.13: Hydraulic Retention time approximation for the vermiﬁlter size

HRT in hr A in m2 length Nominal actual A porosity length

2 1.3186 1.148 1.15 1.3186 fmin

1 0.5254 0.7248 0.725 0.5254 fmax

2 1.051 1.025 1.05 1.1025 fmin

1 0.6593 0.812 0.85 0.7225 fmax

Table 6.14: Hydraulic loading

A HRL(m3/m2/hr) HRL approximation of (m3/m2/min) HRL (m3/m2/min) 0.7349 0.2928 17.569 18 0.4639 0.46389 27.834 28 0.7056 0.305 18.299 18.5 0.4624 0.4654 27.924 28

for the values for the HRL the nominal length of the vermifilter and by multiply it by the depth of the vermifilter layer that is 0.64 m.It was assumed an optimum count for the number of worms and their distribution in the soil area that was made to be 10000 worms/ m2 [123] according to the advised value by Komarowski (2001) and the number was calculated to accommodate precisely for the vermifilter under consideration where the depth of the vermicast layer is 0.3 m as shown in table 6.15:

Page 83 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Table 6.15: Worm Distribution

HRT in hr the Vol- Worms in Actual ume m3 kg/m3 supply 2 0.396 3.96 4.0 1 0.158 1.58 1.6 2 0.3308 3.308 3.31 1 0.2168 2.168 2.17

The characteristics of the untreated muncipal wastewater have been uni- ﬁed between the treatments and adopted from Onchoke et.al 2015 [124] and are shown here as BOD5 (400 mg/l), COD (850 mg/l), TSS (350 mg/l) and TDS (850 mg/l).The documented removal rates by this technology are expressed in table 6.16, and afterwards the lowest removal rate was taken to account for the wcs: Table 6.16: Removal rates

Source type of BOD5 COD TSS TDS wastewater Xing et al Sewage 91-98% 81-86% 97-98% 90-92% (2005) Chaudhari Municipal 98-100% 45% - - (2006) Life (2005) Domestic 97% 75% 94% - Sinha et Domestic 90% 80-90% 90-95% - al.(2008b) Li et Sewage 89.3% 83.5% 89.1% - al.(2009) Lowest re- 89.3% 75% 89.1% 90% moval

The final effluent with the lowest removal rates from the vermifiltration process will be as summarised in table 6.24:

Page 84 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Table 6.17: Final eﬄuent

BOD5−in BOD5−f CODin CODf TSSin TSSf TDSin TDSf 400 42.8 850 212.5 350 38.15 850 85

And the proposed system for the single dwelling unit analysed above is demonstrated in ﬁgure 6.4 and the overall scheme in ﬁgure 6.5:

Figure 6.4: Schematic of Vermiﬁltration system

Page 85 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings Figure 6.5: Scheme of the Vermiﬁltration treatment in a single house

Page 86 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

MFC system

The use of a MFC is incorporated in an environment were there is a deficit in electricity or if the electricity prices are too high that they reflect an economic burden on the citizens. The MFC is implemented to off-set and compensate for a portion of the power supplied by the power supplier or in the case of electricity absence, it is used to close part of the energy gap.

Design Target

The MFC generated electrical power was assessed and designed to account for the lighting requirements in a single apartment and a single dwelling unit, were the power requirements were made based upon the duration of the lighting and its demand as shown in table 6.18. Table 6.18: Estimates of Lighting duration

Condition lighting duration in hrs Summer 4 Winter 7 wcs 16

The lighting electrical requirement was calculated according to the recommendations adopted from easyearth: solutions for sustainable living/ energy eﬃcient lighting, and the voltage and electrical power is evaluated using the power law in equation 6.4 and are illustrated in table 6.20:

Pel = V ∗ I (6.4) and the electrical power consumption is evaluated with 6.5:

kW h = (Pel in watts/1000) ∗ No. of hours (6.5)

To obtain the voltage usage per day the electrical current for the light bulbs it is uniﬁed to 10 kA for LED light according to the LED design guide

Page 87 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings manual [125]. A comparision was made between different MFC that work with domestic wastewater as the feed substrate for electricity generation and the units that will perform for the system of the single house or apartment are reported in tables 6.19 and 6.20. The selected configuraton for the treatment was made by amalgamating the two principles of stream division and MFC for electricity and water treatment to omit the need for primary treatment of the wastewater flow as required by the system proposed by Jiang et al. (2013) [126], and instead another MFC is made for treating the grey water (based on stream division characteristics) to maximise the electric power generation from the water exiting the unit.

Page 88 [127] [126] [128] [32] Ref. 2 Politecnico di Milano - Master’s Thesis in Environmental and Land 2 2 planning Engineering - Academic year 2016/2017 - Awaz Alfadil - W mW/m µ Sustainable Wastewaterdensity Management in Buildings el max P 6.73 mW/m 481 mW/m 55 70.8 COD removal 82.7 77.9 75 71 Coulumbic efficiency NA 14 NA NA oc Max V 0.188 0.2 0.498 0.548 Cathode Graphite rod Carbon fiber brush Carbon cloth Pt coated carbon paper Anode Graphite rod Carbon fiber brush Cardon brush Carbon paper in l For separated streams Working V ol 4.6 0.85 0.13 1 MFC type membrane less Upflow meme- brane less MFC SCMFC two Cham- bered Table 6.19: Comparison between different MFC performances Inoculum Anaerobic sludge Activated sludgeeffluent and primary of clarifier Human urine Anaerobic sludge Substrate Conc. 400 mg COD/l 238.7 mg COD/l 17COD/l g 650 mg- COD/l Waste water Sewage wastewater Domestic wastewater Human urine Human feces

Page 89 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings V/day wcs 0.096 0.032 0.0432 0.0256 0.0288 0.0648 0.096 0.3864 0.096 0.5144 V/day winter 0.042 0.014 0.0189 0.0112 0.0336 0.02835 0.042 0.19005 0.042 0.24605 V/day summer 0.024 0.008 0.0108 0.0064 0.0072 0.0162 0.024 0.0966 0.024 0.1286 kW h/day wcs 0.96 0.32 0.432 0.256 0.288 0.648 0.96 3.864 0.96 5.144 kW h/day winter 0.42 0.14 0.189 0.112 0.336 0.2835 0.42 1.9005 0.42 2.4605 kW h/day summer 0.24 0.08 0.108 0.064 0.072 0.162 0.24 0.966 0.24 1.286 For a single house type switch 3frosted way LED powersumption con- Dimmable globe LED bulb switch 3frosted way LED powersumption con- LED tube lights switch 3frosted way LED powersumption con- switch 3frosted way LED powersumption con- el P 20 10 13.5 16 6/13.5/20 20 Total for Apartment Total for a single house Number 3 2 2 1 3 4 Table 6.20: Estimates of light bulb consumption options for housing: Source easyearth Room bedroom bathroom kitchen hallway living room garageoutdoors and

Page 90 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Selected Conﬁguration

The MFCs are operated in continuous flow mode.The estimated of the amount of power produced by the cell were made using the concept of radiance, were the power density in W/m2 was projected on the area requested to be illuminated which in this case is the area of the apartment and the house and it gave the results using [32] -even though the MFC described by Jianget al. provides more power it requires the constuction of a primary clarifier system [126] -for the fecal water stream (Concentrated black water)from table 6.22. To evaluate the number of fuel cells for the maximum power output the cell were arranged in series to prevent the reverse diode phenomenon from occuring that partially reverses the power production and the MFC become a power sink instead of a power source. For this type of MFC the maximum current achieved is 0.4 mA and the appointed HRT that is approximately 9 days 6.6. The voltage was calculated with the power law equation 6.4 and the number of Fuel Cells for each configuration is given in table 6.21.

Figure 6.6: Power density and Voltage progression in time [32] Page 91 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Table 6.22: Power Generated from a single cell

type of resi- A in m2 kW from one kWh sum- kWh kWh wcs dence MFC mer winter single 242 0.0171336 0.0685344 0.1199352 0.2741376 dwelling (house) apartment 95 0.006726 0.026904 0.047082 0.107616 Table 6.21: Number of operating cells required for each duration and dwelling

Type of Residence No. Summer No. Winter No.wcs Apartment 3 5 10 Single dwelling 4 7 13 (House)

Grey Water MFC

The Grey water characteristics are the same of those described in the vermifiltration and the stream division/LM cases to reach comparable results between the different systems. Referencing the results obtained from Sajithkumar et al. (2015) [26] the maximum power produced by a single cell is in the range of 20 - 25 mW in an operation period of 40 days, and to meet the operation mode of the fecal fed fuel cell (to increase the power production), the grey water fuel cell is operated a 28 days in advance to reach the highest power and voltage capacity and work parallelly with the fecal fed fuel cell. The maximum power density is reach on the 38th day from th initiation of operation and it reaches 307.69 mW/m2 applying also the principle of radiance the power from a single cell is shown in figure 6.7, This energy is then fed to batteries to be used in case of emergency and functions as a power generator,and the general plan is shown in figure 6.8.

Page 92 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Table 6.23: Power Generated from a single cell (Grey water) [26]

type of resi- A in m2 kW from one kWh sum- kWh win- kWh wcs dence MFC mer ter single 242 0.07446098 0.29784392 0.52122686 1.19137568 dwelling (house) apartment 95 0.02923055 0.1169222 0.20461385 0.4676888

Figure 6.7: Performance of grey water powered MFC [26]

Page 93 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings Figure 6.8: Scheme of the MFC treatment in a single house or Apartment

Page 94 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Recommendations for the future:UV disinfection

For each final effluent of the biological treatment a UV disinfection unit was installed to allow for further removal rates and an increase in the quality of the water.The water exiting from the biological treatment is clean enough not to undergo a prior filtration before it enters the UV disinfectant.The choice of the disinfecting process was made to adhere to the concept of making a zero waste/wastewater residential unit and avoid the possible generation of additional waste and the burden of controlling it. when compared with other disinfection systems the UV holds the results shown in figure 6.9. For wastewater treatment the most common used UV instalation is the UV MP lamp compared to the LP and the LP HO that require more units, while the MP ensures compact sizing for this configuration. The UV dosage has been selected from the Mackey,E.D et al., Practrical Aspects of UV Disnfec- tion, AWWA Researsh Foundation and American Water works Association Denver, CO, 2001,pp.106-109. as shown in table 6.24: According to this information a dosage of 40 ml/cm2 rendered the most appropriate for the effluent treatment that carries as well a dicoloration process of the water according to the USEPA UV.

Figure 6.9: Comparison between disinfections approaches for wastewater [33] Page 95 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Table 6.24: UV Dosages for 1=log Inactivation of various organisms

Group Organism UV Dose (ml/cm2) Viruses Poliovirus Type I 4-6 Coxsackievirus 6.9 Hepatitis A 4-5 Rotavirus strain SA II 7-9 Adenovirus Strain 40 30 Adenovirus Strain 41 25-30 Bacteria E.coli ATCC 11229 2.5-5 E.coli O157:H ATCC 43894 1.5 Legionella pneumophila ATCC 43660 3 Salmonella typhi ATCC 19430 2 Shigella dysenteriae ATCC 290287 0.5

Evidence of the registered removal rates was made and is illustrated in ﬁgure 6.10, bearing in mind that the quality of the UV treated water cn be adjusted to meet the areas of demand with the most ﬁtting characteristics of the utilization of the treated water quantity [33]:

Figure 6.10: Inﬂuence of the UV contact time of the treated wastewater [33]

Page 96 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Table 6.25: Water quality with UV installation in mg/l

Removal Water division LM MFCblack MFCgrey Vermiﬁlter rates as %

BODi BODf BODi BODf BODi BODf BODi BODf BODi BODf 90% 550 55 ≤ 10 ≤ 10 105 10.5 75 ≤ 10 42.8 ≤ 10

CODi CODf CODi CODi CODf CODf CODi CODf CODi CODf 70% 800 240 ≤ 10 ≤ 10 179.2 53.76 96.32 28.896 212.5 63.75

Table 6.25 illustrates the ﬁnal eﬄuent BOD and COD values from the previously proposed treatments in case of the incorporation of a UV disinfectant unit.

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Conclusion

The overal purpose of this study was to analyse this implementation of biological systems for the treatment of municipal wastewater and its primarily feasibility in different urban plans (single house or apartment building) to move towards a more decentralized and local treatment method with initial designs of each treatment unit(stream division, LM, MFC and Vermifiltra- tion) to rather give a general understanding of the benefits of the systems and not to intricately design each unit. Each system showed promising results in treating the water, along with serving another purpose from water saving, liquid fertilizer production (the use of a UD),biomass production from the LM, solid fertilizer from vermicompost from the vermifiltration system and electricity generation from MFC. Once designed and operated all the different forms of treatment show to be self sustaining and require minimum to null interference and control. The challange in adopting the biological treatments comes in the substitu- tion of the already existing conventional treatment systems that requires a capital cost, but it must be mentioned that this will be compensated by the generated revenues and resources savings (reduced expenses).While the conventional treatments deteriorate with time and require more frequent pe- riodial maintenance. The results of this study show that these proposed scheme are feasible to be implemented in developing and developing countries and serving the final purpose of water saving and partial providing energy security (electricity from MFC), food security(fertilizer production) and ecosystem proliferation (no landfill or disposal into water streams) to reach guarantee a balance between human rights and nature rights on humans.

Page 98 Appendices

99 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Appendix

Page 100 Politecnico di Milano - Master’s Thesis in Environmental and Land planning Engineering - Academic year 2016/2017 - Awaz Alfadil - Sustainable Wastewater Management in Buildings

Table 26: TSS Removal eﬃciency

Experiment No. untreated wastewater Treated with worms Treated without worms 1 390 28 116 2 374 24 190 3 438 22 184 4 379 27 179 5 407 25 168 Table 27: Turbidity Removal

Experiment No. Untreated wastewater Treated with worms Treated without worms 1 112 1.5 3.6 2 120 0.6 1.5 3 74 1.1 1.2 4 70 1.2 1.8 5 100 1.1 2.0

Table 28: BOD5 Removal

Experiment No. Untreated wastewater Treated with worms Treated without worms 1 309 1.97 86.3 2 260 4.0 45.8 3 316 6.02 63.3 4 328 2.06 83.2 5 275 4.25 63.5 Table 29: COD Removal

Experiment No. Untreated wastewater Treated with worms Treated without worms 1 293 132 245 2 280 153 235 3 280 128 201 4 254 112 217 5 260 139 227

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