Drying Beds

Compiled by:
Dorothee Spuhler (seecon international gmbh)

Executive Summary

Drying beds are either planted or unplanted sealed shallow ponds filled with several drainage layers and designed for the separation of the solid from the liquid fraction of (faecal) sludge from latrines, septic tanks, biogas reactors, trickling filters, etc. Sludge is dried naturally by a combination of percolation and evaporation. When plants are present, evaporation is enhanced by transpiration (evapotranspiration). The percolate still contains pathogens and needs to be collected for treatment or controlled reuse. After treatment in planted drying beds (humification beds), the dried sludge, a nutrient-rich soil amendment, can be directly used in agriculture. If unplanted sludge drying beds are used, additional treatment by composting may be foreseen. Unplanted drying beds need to be desludged before fresh sludge is applied, while humification beds can be filled up intermittently requiring desludging only once ever 5 to 10 years. Drying beds are relatively easy to construct and simple to maintain, although large surface areas and man- or mechanical power is required for regular desludging.

In Out

Faecal Sludge

Compost (for further off-site composting), Soil, Treated Water, Fertigation Water or Water requiering further treatment

All organic degradation processes produce sludge (SASSE & BORDA 1998). Sludges from wastewater collection or treatment units are of variable consistency (from septic tanks, small and large scale anaerobic digesters, anaerobic digesters for organic waste, anaerobic baffled reactors, wastewater stabilisation pond systems, etc.). Generally, they do not have a higher solids content than 2 to 10 %  and can therefore not be transported easily with simple equipment. Apart from this, sludge is contaminated and occupies large volumes for storage (SASSE & BORDA 1998). Therefore it is better to dry or dewater sludge before further use or dumping. Sludge drying beds are one of the simplest and oldest techniques for sludge dewatering (SANIMAS 2005). They are a simple means to reduce the volume of the sludge and prepare reuse as fertiliser.
Sludge drying beds are basically impermeable beds filled with different layers of gravel and sand. Drainage pipes are incorporated in the bottom of the beds.

 

 EAWAG/SANDEC (2008)

Indiscriminate disposal of faecal sludge, Ouagadougou. Source: EAWAG/SANDEC (2008)

 ERIKSEN-HAMEL & DANSO (2002)

Lettuce farm fertilised with safe compost made out of faecal sludge treated in drying beds at Gyenyasi farmers association in Kumasi. Source: ERIKSEN-HAMEL & DANSO (2008)

Sludge is applied in layers on top of the gravel beds and is naturally dried. The bed can be either planted or unplanted. After treatment in planted drying beds (humification beds), the dried sludge, a nutrient-rich soil amendment (or biosolid), can be directly used in agriculture. If unplanted sludge drying beds are used, additional treatment by composting may be foreseen. This allows to stabilise the sludge and to return nutrients and organic matter into the soil for agriculture. The percolate contains pathogens and is collected in the drainage pipes. It can be reused, but then requires treatment.

 TILLEY et al. (2008)

Unplanted and planted drying bed. Source: TILLEY et al. (2008)

A traditional sludge drying bed can be used for dewatering and drying of faecal sludge and anaerobic digester residue. Anaerobic sanitation systems (e.g. latrines, septic tanks, aqua privies, anaerobic baffled reactors, biogas reactors) produce less sludge than aerobic treatments (e.g. from trickling filters, activated sludge) and anaerobic sludge also dries better and results in fewer odours as it is more stabilisedSludge is dewatered by percolation, while the solid fraction remains on the filter surface and is dried by natural evaporation. In planted drying beds, the plants enhance evaporation by transpiration. This process is called evapotranspiration.

In principle the construction of unplanted and planted sludge drying beds is similar to gravel/sand filters, starting with an impermeable shallow pond, drainage pipes in the bottom (perforated PVC pipes or hollow blocks), and different drainage layers. The bed frame is usually made from concrete or a plastic liner with the bottom surfaces slightly sloped in order to facilitate percolation and drainage. The lowest layer of the bed consists of a drainage stratum made of coarse gravel. Upper layers consist of different sand and gravel with finer grain size at the top. For the sludge application, a splash spate may be used to avoid sputtering.

Unplanted Sludge Drying Beds

 STRAUSS & MONTANGERO (2002).

Crosscut of an unplanted drying bed. Source: STRAUSS & MONTANGERO (2002)

Unplanted sludge drying beds are simple sand and gravel filters on which batch loads of sludge are dewatered. Indication about the diameter of the medium and the height of the different gravel and sand layers vary depending on the source (SASSE & BORDA 1998; STRAUSS & MONTANGERO 2004). Generally, the coarse gravel layer (grain diameter: 15 to 50 mm) is within 20 to 30 cm of height. A gravel layer (diameter of 7 to 15 mm) of 10 to 15 cm follows this layer. This layer can be followed of a similar one of slightly lower diameter (see picture below, STRAUSS & MONTANGERO 2002), but this is not compulsory (SASSE 1998). There should be a final sand layer of 25 to 30 cm. As some sand will be lost each time the sludge is manually removed, it may be higher (STRAUSS & MONTANGERO 2004; TILLEY et al. 2008).

 

 EAWAG/SANDEC (2008) and humboldt.edu

Unplanted drying beds in Ghana (left) and rain protected unplanted drying bed at the Arcata wastewater treatment plant, USA (right). Source: EAWAG/SANDEC (2008); HUMBOLDT EDU (2008)

The sludge is applied in a batch mode about once per week intervals in layers of no more than 20 to 30 cm. About 50 to 80 % of the initial volume is removed by percolation (STRAUSS & MONTANGERO 2002), resulting in total solid (TS) content of 20 to 70 % (STRAUSS & MONTANGERO 2004) depending on the local weather conditions and climate. In regions with frequent rainfall, contour bounds can prevent surface runoff to enter the ponds and covering the drying beds with a roof may be considered.

Drying induces partial pathogen removal. However, the dried sludge still may contain pathogens, particularly Helminth eggs, and should therefore be handled carefully and receive further treatment such as composting or prolonged storage before use in agriculture. The percolate from dewatering contains also pathogens, mainly bacteria and viruses and has to be further treated as well (STRAUSS et al. 1997). In the case of frequent application of sludge and to enhance retention times, two or more drying beds can be constructed in parallel and used alternately.
On an annual basis, about 100 to 200 kg TS/m2 can be applied on a drying bed. Drying takes 10 to 20 days. Land requirements are 0.05 m2 per capita for a 10 days cycle (STRAUSS & MONTANGERO 2002). Before fresh sludge is applied, dried sludge needs to be desludged and brought to a composting site, what makes it a rather laborious treatment option.

Planted Sludge Drying Bed (Humification Bed)

 STRAUSS & MONTANGERO 2004

Crosscut of a planted drying bed. Source: STRAUSS & MONTANGERO (2004)

 KONE & KENGE (2008)

Pilot beds of the VFCW developed for faecal sludge dewatering study in sub-Saharan countries. Source: KONE & KENGE (2008)

 EAWAG/SANDEC 2008

Planted sludge drying beds, also designated as reed beds or constructed wetlands, could minimise the need for frequent removal of dried sludge as they can be operated for several years before sludge removal becomes necessary. Source: EAWAG/SANDEC (2008)

As for unplanted beds, planted beds consist of an impermeable shallow pit filled with different layers of coarse to fine sand. Generally, there are three layers, starting with a large gravel layer (diameter of 20mm) of 25 cm height, followed by a fine gravel layer with granules of 5 mm in diameter (also 25 cm height) and finally covered with a sand layer of some 10 cm (EAWAG/SANDEC 2008). Unlike unplanted beds, planted beds do not need desludging before each new application as the root system of the plants maintains the permeability. The sludge is added intermittently once a week and only removed every 5 to 10 years (STRAUSS et al. 1997; STRAUSS & MONTANGERO 2002). Once the sludge is removed it is well mineralised and has a soil-like structure with a TS content of 40 to 70 % (STRAUSS & MONTANGERO 2002). Therefore, planted sludge drying beds are also called humification beds. It is best to stop applying sludge one or two years before removing it (while a parallel bed receives the sludge). In such a way, the humified sludge is nearly pathogen free and can be reused directly as biosolid in agriculture.
Percolate quality also considerably improves by the presence of plants but may still require a polishing treatment (STRAUSS et al. 1997).
Planted beds can receive about 250 kg TS/m2 per year (STRAUSS & MONTANGERO 2002).

Costs Considerations

The investment costs of sludge drying beds are moderate where land prices are low and filter material (gravel/sand) is locally available (SANIMAS 2005). However, the pond may needs to be made impermeable and expert skills are required for design. Operation costs are low as no energy or complicated equipment is required. However, desludging, particular for unplanted beds is laborious.

Operation and Maintenance

Operation and maintenance includes application of sludge, desludging, control of drainage system and the control of the secondary treatments for percolate or dried sludge. Even though experts are not compulsory for the operation and maintenance, a well-organised community group, which has experience in organic fertiliser use and preparation is required (SANIMAS 2005).

Health Aspects

Fresh sludge is generally highly pathogenic and should be handled with care. Also a certain distance to the installed beds (especially when sludge has been recently applied) should be respected. Percolates from sludge drying beds contain also pathogens and need to be further treated.
Sludge from unplanted beds should be composted before reuse to enhance pathogen removal.
Dried sludge from planted drying beds (if there was no fresh application of sludge during the past 1 to 2 years) is generally free from pathogens and can be used directly (STRAUSS et al. 1997).

At a Glance

Working Principle

Drying beds are simple sealed shallow ponds filled with several drainage layers. Sludge is applied on the top and dried by percolation and evaporation. In planted drying beds, the plants maintain the porosity of the soil and enhance the evaporation by transpiration (evaporation). Dried sludge can be used as biosolid in agriculture.

Capacity/Adequacy

Requires large land-surfaces and can cause odour; therefore generally installed in rural areas.

Performance

Depends strongly on the local climate (rain, runoff); TS content of 20 to 70 % can be achieved. Some of NH4 is lost to air. Pathogen removal is moderate for unplanted beds with short retention time, but high for planted drying beds with long retention times.

Costs

Moderate investment costs and low operation costs

Self-help Compatibility

Can be produced with locally available material, but requires expert design. Operation is simple but staff/community should be trained.

O&M

Application of sludge, desludging, control of drainage system and of the secondary treatment for percolate or dried sludge. Desludging for unplanted beds every one to several weeks and every 5 to 10 years for planted drying beds.

Reliability

High, if the area is kept dry (rain, runoff).

Main strength

Low-tech and no requirement of energy.

Main weakness

Requires space; odour can occur; (and frequent desludging in the case of unplanted beds).

Applicability

Sludge drying beds are a secondary treatment for all kinds of sludge, including faecal sludge from on-site sanitation systems, anaerobic digesters at community or large-scale level. But large surface areas are required and odour is frequent. Therefore, they should be constructed far away from housings.
The method is simple but requires professional design and informed manpower for the operation.
Drying beds are not adapted for regions with heavy rainfalls and frequent flooding or where the water table is high. In any case, the ponds should be sealed to prevent infiltration of the pathogen containing percolate and a counter bound can prevent run-off to flow in.
 

Advantages

  • Dried sludge can be used as fertiliser (either directly in the case of planted beds or after composting in the case of unplanted beds)
  • Easy to operate (no experts, but trained community required)
  • High reduction of sludge volume
  • Can achieve pathogen removal
  • Can be built with locally available materials

Disadvantages

  • Requires large land area
  • Requires treatment of percolate
  • Only applicable during dry seasons or needs a roof and contour bund
  • Manual labour or specialised equipment is required to remove dried sludge from beds
  • Can cause odour problems

References Library

Eawag (Editor); Sandec (Editor) (2008): Faecal Sludge Management. Pdf Presentation. Duebendorf: Swiss Federal Institute of Aquatic Science (Eawag), Department of Water and Sanitation in Developing Countries (Sandec). URL [Accessed: 23.05.2012]. PDF

EAWAG/SANDEC (Editor) (2008): Household Water Treatment and Safe Storage (HWTS). Lecture Notes. (= Sandec Training Tool 1.0, Module 3). Duebendorf: Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 08.04.2010]. PDF

ERIKSEN-HAMEL, N.S.; DANSO, G. (2008): Urban Compost: A Socio-economic and Agronomic Evaluation in Kumasi, Ghana. In: REDWOOD, M. (Editor) (2008): Agriculture in Urban Planning: Generating Livelihoods and Food Security. . URL [Accessed: 23.06.2010].

HEINSS, U.; LARMIE, S.A.; STRAUSS, M. (1998): Solids Separation and Pond Systems for the Treatment of Faecal Sludges in the Tropics . Lessons Learnt and Recommendations for Preliminary Design. . (= SANDEC Report, 5). Duebendorf: Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 12.04.2010]. PDF

SANIMAS (Editor) (2005): Informed Choice Catalogue. pdf presentation. BORDA and USAID. PDF

SASSE, L. ; BORDA (Editor) (1998): DEWATS . Decentralised Wastewater Treatment in Developing Countries. Bremen: Bremen Overseas Research and Development Association (BORDA). PDF

STRAUSS, M.; LARMIE, S.A.; HEINSS, U. (1997): Treatment of sludges from on-site sanitation — Low-cost options. In: Water Science and Technology 6, 129-136. URL [Accessed: 23.06.2010]. PDF

STRAUSS, M.; MONTANGERO, A. (2002): FS Management – Review of Practices, Problems and Initiatives. London and Duebendorf: DFID Project R8056, Capacity Building for Effective Decentralised Wastewater Management, Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 24.05.2012]. PDF

MONTANGERO, A.; STRAUSS, M. (2004): Faecal Sludge Treatment. Duebendorf: Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 10.06.2010]. PDF

TILLEY, E.; LUETHI, C.; MOREL, A.; ZURBRUEGG, C.; SCHERTENLEIB, R. (2008): Compendium of Sanitation Systems and Technologies. Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (EAWAG) and. URL [Accessed: 15.02.2010]. PDF

See document in FRENCH

HUMBOLDT EDU (Editor) (2008): Arcata's Wastewater Treatment Plant & The Arcata Marsh and Wildlife Sanctuary. Arcata: Environmental Resources Engineering, Humboldt State University. URL [Accessed: 22.05.2012].

Further Readings Library

Reference icon

ECOSAN CLUB (Editor) (2012): Faecal Sludge Management. (= Sustainable Sanitation Practice, 13). Vienna: Ecosan Club. URL [Accessed: 16.10.2012]. PDF

This issue presents studies from different regions (Bangladesh, Cameroon, Burkina Faso) that mainly show the non-existence of faecal sludge management. Additionally, the last paper describes a new technological solution (LaDePa) for producing hygienically safe organic fertiliser from sludge from ventilated improved pit toilets (VIPs).


Reference icon

HEINSS, U.; STRAUSS, M. (1999): SOS - Management of Sludges from On-Site Sanitation. Co-treatment of Faecal Sludge and Wastewater in Tropical Climates. Duebendorf and Accra: Swiss Federal Institute of Aquatic Science (EAWAG). URL [Accessed: 21.04.2010]. PDF

This article provides operational and design guidance for the co-treatment of faecal sludge in waste stabilisation ponds and in activated sludge sewage treatment plants. Problems which may arise when highly concentrated faecal sludge is not properly included in the design of the co-treatment system are also discussed.


Reference icon

HEINSS, U.; LARMIE, S.A.; STRAUSS, M. (1994): SOS - Management of Sludges from On-Site Sanitation. Characteristics of Faecal Sludges and their Solids-Liquid Separation. Duebendorf and Accra: Swiss Federal Institute of Aquatic Science (EAWAG). PDF

This document gives an overview on the characteristics of different sludges as well as monitoring results and recommendations for design of solid-liquid separation. It is based on a field report.


Reference icon

HEINSS, U.; LARMIE, S.A.; STRAUSS, M. (1998): Solids Separation and Pond Systems for the Treatment of Faecal Sludges in the Tropics . Lessons Learnt and Recommendations for Preliminary Design. . (= SANDEC Report, 5). Duebendorf: Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 12.04.2010]. PDF

The report sets out to provide guidelines for the preliminary design of faecal sludge treatment schemes comprising solids-liquid separation and stabilisation ponds. The document is based on the results of collaborative field research conducted by the Ghana Water Research Institute and SANDEC on full and pilot-scale faecal sludge (FS) treatment plants located in Accra, Ghana.


Reference icon

KLINGEL, F. ; MONTANGERO, A. ; KONE, M.; STRAUSS, M. (2002): Fecal Sludge Management in Developing Countries - A Planning Manual. (= First Edition). Duebendorf: Swiss Federal Institute for Environmental Science (EAWAG). URL [Accessed: 23.06.2010]. PDF

This manual is a first approach to provide guidance on strategic planning of faecal sludge management. The study took place in the City of Nam Dinh, in Vietnam. The main principles for strategic sanitation planning have been adopted from the guide “Strategic Planning for Municipal Planning” from GHK Research and Training Ltd.


Reference icon

MONTANGERO, A.; STRAUSS, M. (2004): Faecal Sludge Treatment. Duebendorf: Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 10.06.2010]. PDF

This document reviews current practices of faecal sludge management and treatment.


Reference icon

MONVOIS, J.; GABERT, J.; FRENOUX, C.; GUILLAUME, M. (2010): How to Select Appropriate Technical Solutions for Sanitation. (= Six Methodological Guides for a Water and Sanitation Services' Development Strategy, 4). Cotonou and Paris: Partenariat pour le Développement Municipal (PDM) and Programme Solidarité Eau (pS-Eau). URL [Accessed: 19.10.2011]. PDF

The purpose of this guide is to assist local contracting authorities and their partners in identifying those sanitation technologies best suited to the different contexts that exist within their town. The first part of the guide contains a planning process and a set of criteria to be completed; these assist you in characterizing each area of intervention so that you are then in a position to identify the most appropriate technical solutions. The second part of the guide consists of technical factsheets which give a practical overview of the technical and economic characteristics, the operating principle and the pros and cons of the 29 sanitation technology options most commonly used in sub-Saharan Africa.

See document in FRENCH


Reference icon

STRAUSS, M.; LARMIE, S.A.; HEINSS, U. (1997): Treatment of sludges from on-site sanitation — Low-cost options. In: Water Science and Technology 6, 129-136. URL [Accessed: 23.06.2010]. PDF

Published in 1997, this article gives an overview on current literature-based knowledge regarding faecal sludge treatment along with results and conclusions from field research.


Reference icon

STRAUSS, M.; DRESCHER, S.; ZURBRUEGG, C.; MONTANGERO, A.; OLUFUNKE, C.; DRECHSEL, P. (2003): Co-composting of Faecal Sludge and Municipal Organic Waste. Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC) and International Water Management Institute (IWMI). URL [Accessed: 23.06.2010]. PDF

The document gives an overview on the combined composting of (faecal) sludges and organic solid waste based on a pilot project in Kumasi, Ghana. Results of the investigation should help the city’s waste management department to develop its biosolids management strategy and enable the project team to develop guidelines for planners and engineers on the option of co-composting.


Reference icon

STRAUSS, M.; BARREIRO, W.C.; STEINER, M.; MENSAH, A.; JEULAND, M.; BOLOMEY, S.; MONTANGERO, A.; KONE, D. (2003): Urban Excreta Management - Situation, Challenges, and Promising Solutions. In: IWA Asia-Pacific Regional Conference Bangkok, Thailand. URL [Accessed: 23.06.2010]. PDF

The objective of this paper is to render planners, decision makers, and consultants aware that faecal sludge management (FSM) should form an integral part of the urban development planning process. For this, three illustrative cases are presented, based on which an array of measures or tools, as well as institutional/regulatory, financial/economic, and technical aspects are discussed.


Reference icon

WINSA (2011): What Happens When the Pit is Full?. Developments in On-Site Faecal Sludge Management (FSM). Durban: Water Information Network South Afrika (WINSA). URL [Accessed: 06.10.2011]. PDF

This seminar report helps people responsible for the sustainable operation of on-site sanitation systems. It shows new developments in the field and contains a lot of detailed information about Faecal Sludge Management (FSM).


Reference icon

VERHAGEN, J.; CARRASCO, M. (2013): Full-Chain Sanitation Services That Last. Non-Sewered Sanitation Services. The Hague: International Water and Sanitation Center (IRC). URL [Accessed: 07.08.2013]. PDF

This paper sets out a framework for the delivery of non-sewered sanitation services that last, are accessible to all and are at scale. The framework is based on IRC International Water and Sanitation’s (IRC) experience and lessons learnt from its engagement in non-sewered sanitation service at scale.


Reference icon

ANDREOLI, C.V. (Editor); SPERLING, M. von (Editor); FERNANDES, F. (Editor) (2007): Sludge Treatment and Disposal. (= Biological Wastewater Treatment Series, 6). London: International Water Association (IWA) Publishing. URL [Accessed: 01.11.2013]. PDF

Sludge Treatment and Disposal is the sixth volume in the series Biological Wastewater Treatment. The book covers in a clear and informative way the sludge characteristics, production, treatment (thickening, dewatering, stabilisation, pathogens removal) and disposal (land application for agricultural purposes, sanitary landfills, landfarming and other methods). Environmental and public health issues are also fully described.


Case Studies Library

Reference icon

KONE, D.; KENGE, I. (2008): Technology Transfer – Forage Plants Used in Faecal Sludge Dewatering Beds in Sub-Saharan Africa. In: Sandec News 9. PDF

In collaboration with the Asian Institute of Technology (AIT), Bangkok, Eawag has previously demonstrated that constructed wetlands, especially in Thailand, offer a viable solution for the treatment of faecal sludge. However, since the characteristics of sludge vary widely from one region to another, appropriate indigenous plants had to be identified so as to ensure successful operation of these facilities.


Reference icon

KONE, D.; STRAUSS, M. (2004): Low-cost Options for Treating Faecal Sludges (FS) in Developing Countries - Challenges and Performance. Duebendorf: Water and Sanitation in Developing Countries (SANDEC), Swiss Federal Institute for Environmental Science (EAWAG). URL [Accessed: 23.06.2010]. PDF

This article analyses and discusses the performances of low-cost technology for treating faecal sludges in developing countries. It shows that where septic tanks are the predominant type of on-site sanitation installations, septage is the only or predominant type of faecal sludge generated. It also shows that constructed wetlands, settling tanks/ponds, or unplanted drying beds might prove suitable as a pre-treatment.


Reference icon

MUELLEGGER, E.; SCHLICK, J.; WERNER, C. (2009): Improvement of Sanitation at Kanawat Health Center Uganda. (= SuSanA - Case Studies). Eschborn: Sustainable Sanitation Alliance (SuSanA) . URL [Accessed: 22.05.2012]. PDF

This study reports the improvement of the sanitation systems of a rural public health centre in Kanawat, Uganda. Excreta from UDDTs and composting pit latrines are treated together in sludge drying beds. Greywater is treated in a sludge drying bed and a constructed wetland and finally reused for irrigation.


Reference icon

OLUFUNKE, C.; DOULAYE, K. (2009): Co-composting faecal sludge & organic solid waste, Kumasi, Ghana. (= SuSanA - Case Studies). Eschborn: Sustainable Sanitation Alliance (SuSanA). URL [Accessed: 22.05.2012]. PDF

This project aimed to gain scientific knowledge on the technical, socio-economical and operational aspects of co-composting (organic solid waste and faecal material). Dried faecal sludge (drying bed) is co-composted with the organic fraction of solid waste. The final product is used as compost for urban and periurban agriculture.


Reference icon

WAFLER, M. (2006): Chapter 3. Pilot Project "Navsarjan Vocational Training Institute Dalit Shakti Kendra". In: WAFLER, M.; HEEB, J. (2006): Report on Case Studies of ecosan Pilot Projects in India. Eschborn. URL [Accessed: 26.04.2010]. PDF

The main aim of the project was to avoid manual scavenging of excreta and to improve the sanitation situation at the Navsarjan Vocational Training Institute. The technical solution proposed was source separation (grey-/blackwater) and reuse. Greywater is separately treated and reused in the garden while the urine and faeces (blackwater) are directly introduced into a biogas plant. Digested sludge is dried on basic drying beds and used as compost for the garden. UDDT were also installed. The concept was implemented and evaluated for its social and cultural acceptability, sustainable and hygienic safety.


Reference icon

ZIMMERMANN, N.; WAFLER, M. (2009): Decentralized Wastewater Mgmt at Adarsh College, Badalapur, Maharashtra, India. (= SuSanA - Case Studies). Eschborn: Sustainable Sanitation Alliance (SuSanA). URL [Accessed: 22.05.2012]. PDF

This case study reports the development of an ecologically sound sanitation concept at Adarsh Bidyaprasarak Sanstha's College of Arts & Commerce. It comprises separate urine collection and a DEWATS system for the treatment of black- and greywater consisting of biogas settler, an anaerobic baffled reactor, and anaerobic filter, a horizontal flow wetland and a polishing pond.


Awareness Raising Material Library

Reference icon

STRAUSS, M.; BARREIRO, W.C.; STEINER, M.; MENSAH, A.; JEULAND, M.; BOLOMEY, S.; MONTANGERO, A.; KONE, D. (2003): Urban Excreta Management - Situation, Challenges, and Promising Solutions. In: IWA Asia-Pacific Regional Conference Bangkok, Thailand. URL [Accessed: 23.06.2010]. PDF

The objective of this paper is to render planners, decision makers, and consultants aware that faecal sludge management (FSM) should form an integral part of the urban development planning process. For this, three illustrative cases are presented, based on which an array of measures or tools, as well as institutional/regulatory, financial/economic, and technical aspects are discussed.


Training Material Library

Reference icon

MONTANGERO, A.; STRAUSS, M. (2004): Faecal Sludge Treatment. Duebendorf: Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 10.06.2010]. PDF

This document reviews current practices of faecal sludge management and treatment.


Reference icon

SASSE, L. ; BORDA (Editor) (1998): DEWATS . Decentralised Wastewater Treatment in Developing Countries. Bremen: Bremen Overseas Research and Development Association (BORDA). PDF

Exhaustive report on technological, operational and economic aspects of decentralised waste water treatment systems. Spreadsheet examples support the reader in designing and planning waste water treatment systems components.


Reference icon

STRAUSS, M.; MONTANGERO, A. (2002): FS Management – Review of Practices, Problems and Initiatives. London and Duebendorf: DFID Project R8056, Capacity Building for Effective Decentralised Wastewater Management, Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 24.05.2012]. PDF

A study on management and institutional aspects regarding the challenges and possible improvements in managing faecal sludge.


Reference icon

SANIMAS (Editor) (2005): Informed Choice Catalogue. pdf presentation. BORDA and USAID. PDF

This informed choice catalogue for community based wastewater treatment technologies helps to identify suitable sanitation options and facilitates the assessment of different sanitation system components with regard to stakeholder preferences. A powerful tool for technical bottom-up planning giving overall information about technical options at a "glance".


Reference icon

UNEP (Editor); Murdoch University (Editor) (2004): Environmentally sound technologies in wastewater treatment for the implementation of the UNEP/GPA "Guidelines on Municipal Wastewater Management". The Hague: United Nations Environment Programme Global Programme of Action (UNEP/GPA), Coordination Office. PDF

Technical information on environmentally sound technologies in wastewater treatment.


Important Weblinks

http://www.eawag.ch/ [Accessed: 23.06.2010]

The department of Water and Sanitation in Developing Countries (SANDEC) at the Swiss Federal Institute of Aquatic Science (EAWAG) is a centre of excellence in the domain of faecal sludge treatment and management and many helpful publications can be downloaded.

http://www.unep.or.jp/ [Accessed: 23.06.2010]

Link to the online version of the “International Source Book On Environmentally Sound Technologies for Wastewater and Stormwater Management” from the United Nations Environmental Programme. This section is about drying beds.