DOCSLIB.ORG

Pollutants in Urban Waste Water and Sewage Sludge 12 2

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Pollutants in Urban Waste Water and Sewage Sludge 12 2 2. Potentially Toxic Elements 2. POTENTIALLY TOXIC ELEMENTS: SOURCES, PATHWAYS, AND FATE THROUGH URBAN WASTEWATER TREATMENT SYSTEMS The aim is to reduce inputs of pollutants entering the wastewater system to background levels because this represents the minimum potential extent of contamination that can be achieved. Potentially toxic elements are of concern because of their potential for long-term accumulation in soils and sediments. The majority of metals transfer to sewage sludge (see Fig 2.1). However, 20% may be lost in the treated effluent, depending on the solubility and this may be as high as 40% - 60% for the most soluble metal, Ni. Although the use of sludge on agricultural land is largely dictated by nutrient content (nitrogen and phosphorus), the accumulation of potentially toxic elements in sewage sludge is an important aspect of sludge quality, which should be considered in terms of the long-term sustainable use sludge on land. Application of sludge to agricultural land is the largest outlet for its beneficial use and this is consistent with EC policy of waste recycling, recovery and use. This is a critical issue due to the increasing amount of sludge produced, the increasingly stringent controls on landfilling, the public opposition to incineration (a potential source of further atmospheric pollution), and the ban on disposal at sea. Consequently sludge quality must be protected and improved in order to secure the agricultural outlet as the most cost effective and sustainable option. Figure 2.1: Origin and fate of metals during treatment of wastewater [from ADEME, 1995] Pollutants in Urban Waste Water and Sewage Sludge 12 2. Potentially Toxic Elements 2.1. Sources and pathways of potentially toxic elements in UWW The average concentrations of potentially toxic elements in domestic and commercial wastewater are given in Table 2.1. The maximum concentrations of potentially toxic elements found in commercial wastewater are generally greater than those in domestic wastewater. This is supported by Scandinavian studies [SFT-1997a, 1997b, 1999] considering all urban sectors together, which judged that commercial and light industrial sectors contributed larger loads of potentially toxic elements to urban wastewater than household sources. Table 2.1 Concentrations of metals in domestic and commercial wastewater [Wilderer and Kolb, 1997 in Munich, Germany] Element Domestic Commercial Wastewater [mg.l-1] Wastewater [mg.l-1] Pb 0.1 £ 13 Cu 0.2 0.04-26 Zn 0.1-1.0 0.03-133 Cd <0.03 0.003-1.3 Cr 0.03 £20 Ni 0.04 £7.3 Table 2.2 Potentially toxic elements in UWW from various sources (% of the total measured in the UWW) Pollutant Country Domestic Commercial Urban Not Reference Wastewater Wastewater Runoff Identified Cd France 20 61 3 16 ADEME, 1995 Norway 40 SFT report 97/28 UK 30 29 41 WRc, 1994 Cu France 62 3 6 29 ADEME, 1995 Norway 30 SFT report 97/28 UK 75 21 4 WRc, 1994 Cr France 2 35 2 61 ADEME, 1995 Norway 20 SFT report 97/28 UK 18 60 22 WRc, 1994 Hg France 4 58 1 37 ADEME, 1995 Pb France 26 2 29 43 ADEME, 1995 Norway 80 SFT report 97/28 UK 43 24 33 WRc, 1994 Ni France 17 27 9 47 ADEME, 1995 Norway 10 SFT report 97/28 UK 50 34 16 WRc, 1994 Zn France 28 5 10 57 ADEME, 1995 Norway 50 SFT report 97/28 UK 49 35 16 WRc, 1994 Pollutants in Urban Waste Water and Sewage Sludge 13 2. Potentially Toxic Elements Cd distribution Cu distribution Domestic Domestic Storm events Storm events Commercial Commercial Non Identified Non Identified Cr distribution Hg distribution Domestic Domestic Storm events Storm events Commercial Commercial Non Identified Non Identified Pb distribution Ni distribution Domestic Domestic Storm events Storm events Commercial Commercial Non Identified Non Identified Zn distribution Domestic Storm events Commercial Non Identified Figure 2.2 Pie charts showing the breakdown of potentially toxic elements entering UWW from different sources in France (ADEME 1995) This uses the French data in Table 2.2 but is included to give a clearer visual representation of the source breakdown for the different metals. Pollutants in Urban Waste Water and Sewage Sludge 14 2. Potentially Toxic Elements The data in Table 2.2 and Figure 2.2 show that for some elements over 50% of the potentially toxic elements in wastewater are unaccounted for. This is in line with findings by Critchley & Agy [1994] Better source inventory data is essential in order to effectively target reductions in emissions from all the different sources. It may be that identification of some of the industrial sources will require increased trade effluent discharge controls if concentrations of pollutants are to be reduced. Domestic and urban run-off sources may require different types of action, such as changes in products used. Emissions of potentially toxic elements from industrial point sources were the major sources of pollution to urban wastewater. However, stringent and more widespread limits applied to industrial users has reduced the levels of potentially toxic elements emitted by industry into urban wastewater considerably. This continues a general decline of potentially toxic elements from industrial sources since the 1960s, due to factors such as cleaner industrial processes, trade effluent controls and heavy industry recession. For example, the liquids used in metal finishing typically contain 3-5 mg.l-1 of copper, 5-10 mg.l-1 of chromium, 3-5 mg.l-1 of zinc, 5-10 mg.l-1 of zinc, 1-5 mg.l-1 of cyanide, and 10-50 mg.l-1 of suspended solids [Barnes, 1987]. However, metal finishing industries are now required to pre-treat these liquids before disposal, reducing toxic discharges by 80-90%. In the Netherlands, a survey of potentially toxic element load in UWW influent [SPEED, 1993], also made estimations for 1995 and forecasts up to 2010. The overall prevalence of potentially toxic elements in the UWW system is expected to decrease, mainly due to a decrease in runoff and industrial sources, while the potentially toxic elements share in WWTS loads from households was expected to increase. As industrial sources of potentially toxic elements in UWW decline, the relevant importance of diffuse sources will increase. Wiart and Reveillere [1995] carried out studies at the Achères WWTS in France. Their studies showed a significant decrease (50-90%) in the potentially toxic element content of sewage sludge since 1978, following the application of the "at-source discharge reduction" policy [Bebin, 1997]. However, the main concern is now with organic pollutants, and current regulations require monitoring of the influent, in order to set up a baseline database from which limits may then be devised. Pollutants in Urban Waste Water and Sewage Sludge 15 2. Potentially Toxic Elements 2.1.1 Domestic sources Domestic sources of potentially toxic elements in wastewater are rarely quantified due to the difficulty in isolating them. Domestic sources include the potentially toxic elements discharged from the household to UWW collecting systems and, in addition, corrosion from materials used in distribution and plumbing networks, tap water and detergents. A study by RIVM (Dutch Institute of Public Health and the Environment) in the Netherlands [SPEED, 1993], quantified the waterborne emissions of potentially toxic elements from household sources, dentistry and utility buildings in the urban environment. Table 2.3 shows the data of waterborne potentially toxic elements emissions in tonnes per annum. Table 2.3 Emissions by Dutch households of potentially toxic elements [adapted from SPEED, 1993]. Potentially Gross waterborne emissions* tonnes.y-1 to surface toxic element water (1993) Household Dentistry Utility buildings sources Copper 94 0.6 27 Zinc 118 - 26 Lead 13 - 3.1 Cadmium 0.7 - 0.2 Nickel 7.3 - 0.9 Chromium 2.9 - 0.3 Mercury 0.3 2.3 0.01 * 96 % of the waterborne emissions are expected to go to the UWW collecting systems, with 4% going directly to surface waters. Domestic products containing potentially toxic elements used on a regular basis at home and/or at work, are also reviewed by Lewis [1999]. The following lists the principal PTEs and products containing them that may enter urban wastewater; Cadmium: is predominantly found in rechargeable batteries for domestic use (Ni-Cd batteries), in paints and photography. The main sources in urban wastewater are from diffuse sources such as food products, detergents and bodycare products, storm water [Ulmgren, 2000a and Ulmgren, 2000b]. Copper: comes mainly from corrosion and leaching of plumbing, fungicides (cuprous chloride), pigments, wood preservatives, larvicides (copper acetoarsenite) and antifouling paints. Mercury: most mercury compounds and uses are now banned or about to be banned, however, mercury is still used in thermometers (in some EU countries) and dental amalgams. Also, mercury can still be found as an additive in old paints for water proofing and marine antifouling (mercuric arsenate), in old pesticides (mercuric chloride in fungicides, insecticides), in wood preservatives (mercuric chloride), in embalming fluids (mercuric chloride), in germicidal soaps and antibacterial products (mercuric chloride and mercuric cyanide), as mercury-silver-tin alloys and for "silver mirrors". Nickel: can be found in alloys used in food processing and sanitary installations; in rechargeable batteries (Ni-Cd), and protective coatings. Lead: The main source of lead is from old lead piping in the water distribution system. It can be found in old paint pigments (as oxides, carbonates), solder, pool cue chalk (as carbonate), in certain cosmetics, glazes on ceramic dishes and porcelain (it is banned now Pollutants in Urban Waste Water and Sewage Sludge 16 2. Potentially Toxic Elements for uses in glazes), also in "crystal glass". Lead has also been found in wines, possibly from the lead-tin capsules used on bottles and from old wine processing installations.
Load more

Recommended publications
  • Use of a Water Treatment Sludge in a Sewage Sludge Dewatering Process
    E3S Web of Conferences 30, 02006 (2018) https://doi.org/10.1051/e3sconf/20183002006 Water, Wastewater and Energy in Smart Cities Use of a water treatment sludge in a sewage sludge dewatering process Justyna Górka1,*, Małgorzata Cimochowicz-Rybicka1 , and Małgorzata Kryłów1 1 University of Technology, Department of Environmental Engineering, 24 Warszawska, Cracow 31- 155, Poland Abstract. The objective of the research study was to determine whether a sewage sludge conditioning had any impact on sludge dewaterability. As a conditioning agent a water treatment sludge was used, which was mixed with a sewage sludge before a digestion process. The capillary suction time (CST) and the specific filtration resistance (SRF) were the measures used to determine the effects of a water sludge addition on a dewatering process. Based on the CST curves the water sludge dose of 0.3 g total volatile solids (TVS) per 1.0 g TVS of a sewage sludge was selected. Once the water treatment sludge dose was accepted, disintegration of the water treatment sludge was performed and its dewaterability was determined. The studies have shown that sludge dewaterability was much better after its conditioning with a water sludge as well as after disintegration and conditioning, if comparing to sludge with no conditioning. Nevertheless, these findings are of preliminary nature and future studies will be needed to investigate this topic. 1 Introduction Dewatering of sludge is a very important stage of the sludge processing. It reduces both sludge mass and volume, which consequently reduces costs of a further sludge processing, facilitates its transport and allows for its thermal processing.
    [Show full text]
  • A Novel Waste Water Treatment Plant for the Disposal of Organic Waste from Mobile Toilets
    A Novel Waste Water Treatment Plant for The Disposal of Organic Waste from Mobile Toilets A Novel Waste Water Treatment Plant for The Disposal of Organic Waste from Mobile Toilets G. BONIFAZI, R. GASBARRONE, R. PALMIERI, G. CAPOBIANCO, S. SERRANTI Departments of Medical Sciences and Biotechnologies and of Chemical Eng. Materials, Environment- Sapienza University of Rome, Abstract The EU wastewater management industry is continuously looking for innovative technological solutions that can enter the market with a reduced environmental impact. This paper focuses on the problems associated to the disposal of human waste and on the specific market of the so-called mobile toilets. These are independent portable units equipped with sanitary tools that use chemical agents to disinfect the vessel and not connected to the sewer network. With growing awareness towards effective sanitation, mobile toilets have gained immense popularity in recent years and are now widely used at construction sites, event venues, public places, and in several other application like temporary refugee housing, migrants’ camps, military missions, cases of natural disasters, airplanes, trains, campers, caravans and campsites. This paper illustrates a new process for the disposal of organic waste from mobile toilets. Keywords: Waste Water Treatment Plants, Chemical Portable Toilets, Use of sludges in agriculture. 1. Introduction into surface and ground water and to avoid toxic effects on soil, plants, animals and humans. In The use of sludge in agriculture within the EU is most cases, national authorities have currently regulated only by the limits of heavy implemented policies supporting the use of metals (Cd, Cu, Hg, Ni, Pb and Zn) listed in sludge in agriculture, as it is considered to be the Council Directive 86/278/EEC.
    [Show full text]
  • 2.2 Sewage Sludge Incineration
    2.2 Sewage Sludge Incineration There are approximately 170 sewage sludge incineration (SSI) plants in operation in the United States. Three main types of incinerators are used: multiple hearth, fluidized bed, and electric infrared. Some sludge is co-fired with municipal solid waste in combustors based on refuse combustion technology (see Section 2.1). Refuse co-fired with sludge in combustors based on sludge incinerating technology is limited to multiple hearth incinerators only. Over 80 percent of the identified operating sludge incinerators are of the multiple hearth design. About 15 percent are fluidized bed combustors and 3 percent are electric. The remaining combustors co-fire refuse with sludge. Most sludge incinerators are located in the Eastern United States, though there are a significant number on the West Coast. New York has the largest number of facilities with 33. Pennsylvania and Michigan have the next-largest numbers of facilities with 21 and 19 sites, respectively. Sewage sludge incinerator emissions are currently regulated under 40 CFR Part 60, Subpart O and 40 CFR Part 61, Subparts C and E. Subpart O in Part 60 establishes a New Source Performance Standard for particulate matter. Subparts C and E of Part 61--National Emission Standards for Hazardous Air Pollutants (NESHAP)--establish emission limits for beryllium and mercury, respectively. In 1989, technical standards for the use and disposal of sewage sludge were proposed as 40 CFR Part 503, under authority of Section 405 of the Clean Water Act. Subpart G of this proposed Part 503 proposes to establish national emission limits for arsenic, beryllium, cadmium, chromium, lead, mercury, nickel, and total hydrocarbons from sewage sludge incinerators.
    [Show full text]
  • Energy Recovery from Sewage Sludge: the Case Study of Croatia
    energies Article Energy Recovery from Sewage Sludge: The Case Study of Croatia Dinko Đurđevi´c 1,* , Paolo Blecich 2 and Željko Juri´c 1 1 Energy Institute Hrvoje Požar, 10000 Zagreb, Croatia; [email protected] 2 Faculty of Engineering, University of Rijeka, 51000 Rijeka, Croatia; [email protected] * Correspondence: [email protected] Received: 26 April 2019; Accepted: 16 May 2019; Published: 20 May 2019 Abstract: Croatia produced 21,366 tonnes of dry matter (DM) sewage sludge (SS) in 2016, a quantity expected to surpass 100,000 tonnes DM by 2024. Annual production rates for future wastewater treatment plants (WWTP) in Croatia are estimated at 5.8–7.3 Nm3/people equivalent (PE) for biogas and 20–25 kgDM/PE of sewage sludge. Biogas can be converted into 12–16 kWhel/PE of electricity and 19–24 kWhth/PE of heat, which is sufficient for 30–40% of electrical and 80–100% of thermal autonomy. The WWTP autonomy can be increased using energy recovery from sewage sludge incineration by 60% for electricity and 100% of thermal energy (10–13 kWhel/PE and 30–38 kWhth/PE). However, energy for sewage sludge drying exceeds energy recovery, unless solar drying is performed. 2 The annual solar drying potential is estimated between 450–750 kgDM/m of solar drying surface. The lower heating value of dried sewage sludge is 2–3 kWh/kgDM and this energy can be used for assisting sludge drying or for energy generation and supply to WWTPs. Sewage sludge can be considered a renewable energy source and its incineration generates substantially lower greenhouse gases emissions than energy generation from fossil fuels.
    [Show full text]
  • Mobility of Heavy Metals in Municipal Sewage Sludge from Different Throughput Sewage Treatment Plants
    Pol. J. Environ. Stud. Vol. 21, No. 6 (2012), 1603-1611 Original Research Mobility of Heavy Metals in Municipal Sewage Sludge from Different Throughput Sewage Treatment Plants Jarosław Gawdzik1*, Barbara Gawdzik2** 1Faculty of Civil and Environmental Engineering, Kielce University of Technology, Division of Waste Management, Al. 1000-lecia Państwa Polskiego 7, 25-314 Kielce, Poland 2Institute of Chemistry, Faculty of Mathematics and Science, Jan Kochanowski University of Humanities and Sciences, Świętokrzyska 15, 25-406 Kielce, Poland Received: 27 June 2011 Accepted: 11 May 2012 Abstract Sewage sludge heavy metals can be dissolved, precipitated, co-precipitated with metal oxides, and adsorbed or associated on the particles in biological debris. Heavy metals are found in the form of oxides, hydroxides, sulphides, sulphates, phosphates, silicates, organic bindings forming complexes with humic com- pounds, and complex sugars. Polish regulations specifying the maximum levels of heavy metals in municipal sewage sludge used for agricultural purposes refer to the total content of lead, cadmium, mercury, nickel, zinc, copper, and chromium. The aim of our study was to evaluate the mobility of heavy metals in sewage sludge from wastewater treatment plants in Świętokrzyskie Province. Stabilized sewage sludge from wastewater treatment was ana- lyzed in accordance with the extraction method proposed by the Community Bureau of Reference (BCR). Zinc, cadmium, lead, and nickel were determined by means of the standard addition with the use of a Perkin-Elmer 3100-BG FAAS atomic absorption spectrophotometer. Chromium and copper were tested using the FAAS technique. The sequence analysis revealed the presence of heavy metals in all fractions (F-I, F-II, F-III, F-IV).
    [Show full text]
  • Circular Economy in Wastewater Treatment Plant– Challenges and Barriers †
    Proceedings Circular Economy in Wastewater Treatment Plant– Challenges and Barriers † Ewa Neczaj * and Anna Grosser Faculty of Infrastructure and Environment, Czestochowa University of Technology, 42-201 Czestochowa, Poland; [email protected] * Correspondence: [email protected]; Tel.: +48-343-250-917 † Presented at the 3rd EWaS International Conference on “Insights on the Water-Energy-Food Nexus”, Lefkada Island, Greece, 27–30 June 2018. Published: 31 July 2018 Abstract: The urban wastewater treatment plants can be an important part of circular sustainability due to integration of energy production and resource recovery during clean water production. Currently the main drivers for developing wastewater industry are global nutrient needs and water and energy recovery from wastewater. The article presents current trends in wastewater treatment plants development based on Circular Economy assumptions, challenges and barriers which prevent the implementation of the CE and Smart Cities concept with WWTPs as an important player. WWTPs in the near future are to become “ecologically sustainable” technological systems and a very important nexus in SMART cities. Keywords: circular economy; wastewater treatment plant; resource recovery 1. Introduction The circular economy (CE) is the concept in which products, materials (and raw materials) should remain in the economy for as long as possible, and waste should be treated as secondary raw materials that can be recycled to process and re-use [1]. This distinguishes it from a linear economy based on the, ‘take-make-use-dispose’ system, in which waste is usually the last stage of the product life cycle. CE is a concept promotes sustainable management of materials and energy by minimalizing the amount of waste generation and their reuse as a secondary material.
    [Show full text]
  • Sludge Treatment and Disposal Biological Wastewater Treatment Series
    Sludge Treatment and Disposal Biological Wastewater Treatment Series The Biological Wastewater Treatment series is based on the book Biological Wastewater Treatment in Warm Climate Regions and on a highly acclaimed set of best selling textbooks. This international version is comprised by six textbooks giving a state-of-the-art presentation of the science and technology of biological wastewater treatment. Titles in the Biological Wastewater Treatment series are: Volume 1: Wastewater Characteristics, Treatment and Disposal Volume 2: Basic Principles of Wastewater Treatment Volume 3: Waste Stabilisation Ponds Volume 4: Anaerobic Reactors Volume 5: Activated Sludge and Aerobic Biofilm Reactors Volume 6: Sludge Treatment and Disposal Biological Wastewater Treatment Series VOLUME SIX Sludge Treatment and Disposal Cleverson Vitorio Andreoli, Marcos von Sperling and Fernando Fernandes (Editors) Published by IWA Publishing, Alliance House, 12 Caxton Street, London SW1H 0QS, UK Telephone: +44 (0) 20 7654 5500; Fax: +44 (0) 20 7654 5555; Email: [email protected] Website: www.iwapublishing.com First published 2007 C 2007 IWA Publishing Copy-edited and typeset by Aptara Inc., New Delhi, India Printed by Lightning Source Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the UK Copyright, Designs and Patents Act (1998), no part of this publication may be reproduced, stored or transmitted in any form or by any means, without the prior permission in writing of the publisher, or, in the case of photographic reproduction, in accordance with the terms of licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licenses issued by the appropriate reproduction rights organization outside the UK.
    [Show full text]
  • Hard Facts About the Risks and Benefits of Using Treated Sewage Sludge/Biosolids on Land
    Hard Facts about the Risks and Benefits of using Treated Sewage Sludge/Biosolids on Land Benefits Biosolids, also known as treated sewage sludge reduce the need for frequent water are a source of organic matter, nitrogen, applications and can facilitate water phosphorus, and micronutrients. These materials conservation. are beneficial to agriculture, silviculture, • Sometimes biosolids are chemically stabilized horticulture, and land reclamation activities and with liming agents. Liming agents increase they improve agricultural productivity. More soil pH and can improve the soils ability to specifically, the benefits derived from biosolids soak in water. Higher pH soils tend to bind used as a soil amendment are as follows: most heavy metals, decreasing the chance of • Nitrogen is a basic nutrient for plant growth. the metals migrating to the ground water. It is present in different forms. In biosolids, it Risks and Benefits taken from the California State Water is present in the forms of ammonia, nitrates, Resources Control Board, “General Waste Discharge and organic nitrogen. The ammonia and Requirements for the Discharge of Biosolids to Land for Use as a Soil Amendment in Agricultural, Silvicultural, Horticultural, and nitrate forms of nitrogen are available for Land Reclamation Activities.” August, 2000. plant usage. Organic nitrogen is released slowly over many months, providing a continuous supply of nitrogen for crops and minimizing the potential for movement of nitrogen to ground water. Total nitrogen available to the plant at any given time is less than the total of these mineral forms due to the dynamic cycling of nitrogen in the soil. • Phosphorus is a basic nutrient for plant growth and is present in all biosolids in varying concentrations.
    [Show full text]
  • Fecal Sludge Management in Developing Countries a Planning Manual
    First edition 2002 Fecal Sludge Management in Developing Countries A planning manual F l o r i a n K l i n g e l , Agnès Montangero, Doulaye Koné, and Martin Strauss Swiss Federal Institute for Environmental Science & Technology Department for Water and Sanitation in Developing Countries Planning of Fecal Sludge Management Foreword This manual has been produced by SANDEC, the Department of Water and Sanitation in Developing Countries, which is part of the Swiss Federal Institute for Environmental Science and Technology (EAWAG). The main principles for strategic sanitation planing have been adopted from the guide “Strategic Planning for Municipal Planning” from GHK Research and Training Ltd. SANDEC has carried out a case study of fecal sludge management in order to enlighten the issues specific to planning of fecal sludge management. This study took place in the City of Nam Dinh, in Vietnam. The corresponding study report “Septage Management Study Nam Dinh” has been issued by SANDEC and the Nam Dinh Urban Development Project (funded by the Swiss Agency for Development and Cooperation). This manual is a first approach to provide guidance on strategic planning of fecal sludge management. It is intended to further develop this manual. Therefore SANDEC will highly appreciate your comments and suggestions on the manual. For further information and comments, please contact Mr. Martin Strauss at: Swiss Federal Institute for Environmental Science and Technology (EAWAG) Water and Sanitation in Developing Countries (SANDEC) Management of Sludge
    [Show full text]
  • Faecal Sludge Treatment and Regulations……………… 5 4
    Contents Acronyms, Abbreviations and Glossary 1. Current Practice and Problems in Faecal Sludge Management………………………………………………….. 1 2. Strategic Aspects……………………………………………. 2 3. Faecal Sludge Treatment and Regulations……………… 5 4. Faecal Sludge Characteristics……………………………. 8 4.1 Resource Value of Human Excreta……………………………. 8 4.2 Faecal Sludge Quality and Variability…………………………. 9 4.3 Faecal Sludge Quantities………………………………………. 12 4.4 Influence of Faecal Sludge Characteristics on Treatment Schemes…………………………………………………….……. 13 5. Faecal Sludge Treatment…………………………………… 15 5.1 Overview of Faecal Sludge Treatment Options……………….15 5.2 Solids-Liquid Separation………………………………….……… 15 5.3 Pond Treatment…………………………………………………… 17 5.3.1 The Use of Anaerobic Ponds……………………………….. 17 5.3.2 Anaerobic Pond Loading and Performance……………….. 18 5.3.3 Ammonia Toxicity…………………………………………….. 19 5.3.4 Problems encountered when Co-treating Faecal Sludge and Wastewater in Waste Stabilization Ponds…………….20 6. Specific Treatment Options………………………………… 21 6.1 Sedimentation/Thickening Tanks – Accra/Ghana….………….21 6.2 Drying Beds – Accra/Ghana…………………………………….. 22 6.3 Land Requirement for Sedimentation/Thickening Tanks and Sludge Drying Beds – Accra/Ghana …………………………… 24 6.4 Constructed Wetlands for the Treatment of Septage – Bangkok/Thailand………………………………………………….25 6.5 Waste Stabilization Ponds for the Treatment of Faecal Sludge Supernatant – Accra/Ghana…………………………………….. 27 6.6 Co-Treatment of Septage and Wastewater in Ponds – Alcorta/Argentina………………………………………………….29 7. Evaluation of Treatment Options………………………….
    [Show full text]
  • Sewage Sludge.01.Qxd
    ash-handling systems and then disposed at landfills. Sludge Incineration Multiple Hearth Furnace Ash from fluidized-bed units is very fine and can be Cost and Technical Feasibility removed with periodic sand changes and continuous Cooling ncineration is a sludge disposal option that Air Discharge scrubbing of the exhaust. Ash disposal is regulated hen considering whether or not to incinerate I involves the firing of sewage sludge at high under solid waste disposal regulations. Beneficial use Wsludge, or which incineration technology to temperatures in an enclosed structure. This process of this ash is actively being investigated. use, cost is always a major consideration. A sludge reduces the sludge to a mass of ash that is less than incinerator is a very mechanized and capital-intensive 20 percent of its original volume. EPA and the states Air Pollution Control Equipment investment that must be managed with a high level of generally support the beneficial use of sludge. Many Sewage expertise and attention to maintenance. Sludge urban sewage treatment facilities produce large Gas Inlet The incineration option is a long-term commitment volumes of sludge and have limited available space Exhaust n general, air pollution control devices are used to for sludge management. They are likely to see I either remove small particles and metals in the that is most cost-effective for large volume wastewater incineration as their most viable option. exhaust gas or to further decompose organics. Devices treatment systems or as a regional solution. In such as wet scrubbers and dry and wet electrostatic evaluating this option, communities must consider Sludge incineration eliminates some environmental precipitators are used to remove metals.
    [Show full text]
  • Sewage Sludge Disposal and Utilization Study
    Sewage Sludge Disposal and Utilization Study Jane Hope January 1986 Washington State Institute for Public Policy 110 East Fifth Avenue, Suite 214 Post Office Box 40999 Olympia, Washington 98504-0999 Telephone: (360) 586-2677 FAX: (360) 586-2793 URL: http://www.wa.gov/wsipp Document No. 86-01-4101 WASHINGTON STATE INSTITUTE FOR PUBLIC POLICY Mission The Washington Legislature created the Washington State Institute for Public Policy in 1983. A Board of Directors—representing the legislature, the governor, and public universities—governs the Institute, hires the director, and guides the development of all activities. The Institute’s mission is to carry out practical research, at legislative direction, on issues of importance to Washington State. The Institute conducts research activities using its own policy analysts, academic specialists from universities, and consultants. New activities grow out of requests from the Washington legislature and executive branch agencies, often directed through legislation. Institute staff work closely with legislators, as well as legislative, executive, and state agency staff to define and conduct research on appropriate state public policy topics. Current assignments include projects in welfare reform, criminal justice, education, youth violence, and social services. Board of Directors Senator Karen Fraser Lyle Quasim, Department of Social and Health Services Senator Jeanine Long Dick Thompson, Office of Financial Management Senator Valoria Loveland David Dauwalder, Central Washington University Senator
    [Show full text]