Land Application of Sludge

Compiled by:
Eawag (Swiss Federal Institute of Aquatic Science and Technology)
Adapted from:
TILLEY, E.; ULRICH, L.; LUETHI, C.; REYMOND, P.; ZURBRUEGG, C. (2014)

Executive Summary

Depending on the treatment type and quality, digested or stabilized sludge can be applied to public or private lands for landscaping or agriculture. Land application of sludge is similar to application of dehydrated faeces or application of pit humus and compost.

Introduction

Sludge that has been treated (e.g., co-composted or removed from a planted drying bed, etc.) can be used in agriculture, home gardening, forestry, sod and turf growing, landscaping, parks, golf courses, mine reclamation, as a dump cover, or for erosion control. Although sludge has lower nutrient levels than commercial fertilizers (for nitrogen, phosphorus and potassium, respectively), it can replace them fully or in part. Additionally, treated sludge has been found to have properties superior to those of fertilizers, such as bulking and water retention properties, and the slow, steady release of nutrients.

 TILLEY et al. (2014)

Schematic of land application of sludge. Source: TILLEY et al. (2014)

Design Considerations

Solids are spread on the ground surface using conventional manure spreaders, tank trucks or specially designed vehicles. Liquid sludge (e.g., from anaerobic reactors) can be sprayed onto or injected into the ground.

Application rates and usage of sludge should take into account the presence of pathogens and contaminants, and the quantity of nutrients available so that it is used at a sustainable and agronomic rate (see also Reuse of Urine and Faeces in Agriculture).

Health Aspects/Acceptance

The greatest barrier to the use of sludge is, generally, acceptance. However, even when sludge is not accepted by agriculture or local industries, it can still be useful for municipal projects and can actually provide significant savings (e.g., mine reclamation).

Depending on the source of the sludge and on the treatment method, it can be treated to a level where it is generally safe and no longer generates significant odour or vector problems. Following appropriate safety and application regulations is important. WHO guidelines on excreta use in agriculture (Volume IV) should be consulted for detailed information.

Operation & Maintenance

Spreading equipment must be maintained to ensure continued use. The amount and rate of sludge application should be monitored to prevent overloading and, thus, the potential for nutrient pollution of soil or groundwater. Workers should wear appropriate protective clothing.

Applicability

Hygienised sludge can be applied as soil conditioner wherever land is available and appropriate safety and application regulations are respected (see also WHO guidelines on excreta use in agriculture (Volume IV)).

Although sludge is sometimes criticized for containing potentially high levels of metals or contaminants, commercial fertilizers are also contaminated to varying degrees, most likely with cadmium or other heavy metals. Faecal sludge from pit latrines should not have any chemical inputs and is, therefore, not a high-risk source of heavy metal contamination. Sludge that originates at large-scale wastewater treatment plants is more likely to be contaminated since it receives industrial and domestic chemicals, as well as surface water run-off, which may contain hydrocarbons and metals. Depending on the source, sludge can serve as a valuable and often much-needed source of nutrients. Application of sludge on land may be less expensive than disposal.

Advantages

  • Can reduce the use of chemical fertilizers and improve the water-holding capacity of soil
  • Can enhance agricultural productivity
  • Can accelerate reforestation
  • Can reduce erosion
  • Low cost
  • Safe management of sludge can avoid inappropriate disposal and environmental pollution

Disadvantages

  • Odours are normally noticeable, depending on prior treatment
  • May require special spreading equipment
  • May pose public health risks, depending on its quality and application
  • Requires knowledge on how to safely reuse it without health or environmental risk
  • Micropollutants may accumulate in the soil and contaminate groundwater
  • Social acceptance may be low in some areas

References Library

STRANDE, L. (Editor); RONTELTAP, M. (Editor); BRDJANOVIC, D. (Editor) (2014): Faecal Sludge Management. Systems Approach for Implementation and Operation. London: IWA Publishing. URL [Accessed: 16.07.2014].

U.S. EPA (Editor) (1999): Biosolids Generation, Use, and Disposal in the United States. Washington: United States Environmental Protection Agency. URL [Accessed: 24.08.2010].

U.S. EPA (Editor) (1994): A Plain English Guide to the EPA Part 503 Biosolids Rule. Washington: : United States Environmental Protection Agency (U.S. EPA). URL [Accessed: 25.03.2014].

WHO (Editor) (2006): Guidelines for the safe use of wastewater excreta and greywater. Volume IV. Excreta and Greywater Use in Agriculture. Geneva: World Health Organisation. URL [Accessed: 26.02.2010].

TILLEY, E.; ULRICH, L.; LUETHI, C.; REYMOND, P.; ZURBRUEGG, C. (2014): Compendium of Sanitation Systems and Technologies. 2nd Revised Edition. Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (Eawag). URL [Accessed: 28.07.2014].

Further Readings Library

Reference icon

TILLEY, E.; ULRICH, L.; LUETHI, C.; REYMOND, P.; SCHERTENLEIB, R.; ZURBRUEGG, C. (2014): Compendium of Sanitation Systems and Technologies (Arabic). 2nd Revised Edition. Duebendorf, Switzerland: Swiss Federal Institute of Aquatic Science and Technology (Eawag). PDF

This is the Arabic version of the Compendium of Sanitation Systems and Technologies. The Compendium gives a systematic overview on different sanitation systems and technologies and describes a wide range of available low-cost sanitation technologies.


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].

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.


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HERSELMAN, J. E.; BURGER, L. W.; MOODLEY, P. (2008): Guidelines for the Utilisation and Disposal of Wastewater Sludge. Volume 5: Requirements for thermal sludge management practices and for commercial products containing sludge. Pretoria: Water Research Commission (WRC). URL [Accessed: 01.01.1970].

Traditional practices related to wastewater sludge management include dedicated land disposal, waste piling, landfill disposal and, to a lesser degree, use in agricultural practices. However, due to varying reasons, on-site land disposal and waste piling have become the standard management options for many wastewater treatment plants in South Africa today. With sludge production increasing on a daily basis, it has however become apparent that current practices are unsustainable with sludge management becoming a problem for many municipalities in South Africa. Innovative solutions need to be sought to create opportunities that provide a wide spectrum of options to the management of wastewater sludge. This guideline aims to provide options and opportunities for this innovation and to encourage the beneficial use of wastewater sludge. Where wastewater sludge cannot be used as a resource, the guidelines also provide for its disposal in a responsible manner.


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].

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.


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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].

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


Reference icon

SPERLING, M. von (2007): Basic Principles of Wastewater Treatment. (= Biological Wastewater Treatment Series, 2). London: International Water Association (IWA) Publishing. URL [Accessed: 01.11.2013].

Basic Principles of Wastewater Treatment is the second volume in the series Biological Wastewater Treatment, and focusses on the unit operations and processes associated with biological wastewater treatment. The major topics covered are: microbiology and ecology of wastewater treatment, reaction kinetics and reactor hydraulics, conversion of organic and inorganic matter, sedimentation, aeration.


Reference icon

STRANDE, L. (Editor); RONTELTAP, M. (Editor); BRDJANOVIC, D. (Editor) (2014): Faecal Sludge Management. Systems Approach for Implementation and Operation. London: IWA Publishing. URL [Accessed: 16.07.2014].

This is the first book to compile the current state of knowledge on faecal sludge management. It addresses the organization of the entire faecal sludge management service chain, from the collection and transport of sludge, to the current state of knowledge of treatment options, and the final end use or disposal of treated sludge. It presents an integrated approach that brings together technology, management, and planning, based on Sandec’s 20 years of experience in the field. It also discusses important factors to consider when evaluating and upscaling new treatment technology options. The book is designed for undergraduate and graduate students, engineers, and practitioners in the field who have some basic knowledge of environmental and/or wastewater engineering.


Reference icon

LEBLANC, R.J. (Editor); MATTHEWS, P. (Editor); RICHARD, R.P. (Editor) (2008): Global Atlas of Excreta, Wastewater Sludge, and Biosolids Management. Moving forward the Sustainable and Welcome Uses of a Global Resource. Nairobi: United Nations Human Settlements Programme (UN-HABITAT). URL [Accessed: 10.04.2014].

In this atlas, a variety of countries and regions in the world report on sanitation in their respective jurisdictions. They range from developing countries with substantial portions of the population without access to modern plumbing or sanitation, to developed countries with sophisticated treatment plants linked to elaborate sewerage systems. They range from countries trying to deal with outmoded sanitation systems to others that have been able to invest in the most modern technology and equipment.


Reference icon

VIGNESWARAN, S.; KANDASAMY, J. (n.y.): Sludge Treatment Technologies. Paris: UNESCO-EOLSS (Encyclopedia Of Life Support Systems). URL [Accessed: 24.11.2011].

This document describes several steps of sludge treatment technologies such as sludge stabilisation, dewatering and incineration.


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U.S. EPA (Editor) (2006): Emerging Technologies for Biosolids Management. (= EPA 832-R, 5/6). United States Environmental Protection Agency, Office of Wastewater Management.


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U.S. EPA (Editor) (1999): Biosolids Generation, Use, and Disposal in the United States. Washington: United States Environmental Protection Agency. URL [Accessed: 24.08.2010].

This report gives an overview on the use and disposal of biosolids/sewage sludge in the US between 1998 and 2010.


Case Studies Library

Reference icon

ROBBINS, D.; STRANDE, L.; DOCZI, J. (2012): Opportunities in Fecal Sludge Management for Cities in Developing Countries: Experiences from the Philippines. North Carolina: RTI International . URL [Accessed: 15.01.2013].

In July 2012, a team from RTI International deployed to the Philippines to evaluate four FSM programs with the goal of reporting on best practices and lessons learned. The four cases—Dumaguete City, San Fernando City, Maynilad Water for the west zone of metro Manila, and Manila Water from the east zone of metro Manila—were chosen to highlight their different approaches to implementing FSM.


Reference icon

HAENEL, M. (n.y.): Sustainable and safe application of sludge and wastewater in Short-Rotation-Plantation. Bremerhaven: Technologie-Transfer-Zentrum Bremerhaven (ttz). URL [Accessed: 21.04.2012].

This presentation on the implementation of sewage fertilized short rotation plantations in developing countries gives an overview on the main principles, technology details and examples of successfully implemented SRPs, including many pictures and photographs.


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EUBIA (Editor) (2008): Short Rotation Plantations: Opportunities for Efficient Biomass Production with the Safe Application of Wastewater and Sewage Sludge. Brussels: European Biomass Industry Association (EUBIA). URL [Accessed: 04.08.2010].

This two-page factsheet by the European Biomass Industry Association gives a brief and concise overview on the topic of Short Rotation Plantations. Especially the benefits of this technology are highlighted.


Awareness Raising Material Library

Reference icon

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

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

KONE, D.; STRAUSS, M.; SAYWELL, D. (2007): Towards an Improved Faecal Sludge Management (FSM). Duebendorf: EAWAG/SANDEC. URL [Accessed: 15.12.2010].

More than two billion urban dwellers in developing countries use on-site sanitation facilities such as pit latrines, septic tanks and aqua privies for excreta and wastewater disposal. Since on-site sanitation installations will serve the growing urban populations in developing countries for decades to come, increasing faecal sludge quantities will have to be managed. Proper faecal sludge management (FSM) is the important link missing in integrated urban sanitation upgrading efforts.


Reference icon

RULKENS, W. (2007): Sewage Sludge as a Biomass Resource. In: Energy & Fuels 2008 22, 9–15. URL [Accessed: 04.07.2012].

The aim of this paper, which is based on a literature review, is to discuss the various options to recover energy from sewage sludge and to assess qualitatively these options with respect to the development stage, potential of energy recovery, and expected future developments. In this evaluation the effect of the presence of toxic organic and inorganic components in the sludge is also assessed.


Training Material Library

Reference icon

EAWAG/SANDEC (Editor) (2008): Faecal Sludge Management. Lecture Notes. (= Sandec Training Tool 1.0, Module 5). Duebendorf: Swiss Federal Institute of Aquatic Science (EAWAG), Department of Water and Sanitation in Developing Countries (SANDEC). URL [Accessed: 23.05.2012].

This module pays special attention to the haulage, treatment and reuse or disposal of faecal sludge. It covers both technical and non-technical (socio-cultural, economic, political etc.) aspects and provides practical information on design, financing and planning of faecal sludge treatment plants.


Reference icon

EAWAG (Editor); SANDEC (Editor) (2008): Faecal Sludge Management. Pdf Presentation. (= Sandec Training Tool 1.0, Module 5). Duebendorf: Swiss Federal Institute of Aquatic Science (Eawag), Department of Water and Sanitation in Developing Countries (Sandec). URL [Accessed: 23.05.2012].

A presentation about faecal sludge management in developing countries.


Reference icon

U.S. EPA (Editor) (1995): Surface Disposal of Sewage Sludge and Domestic septage. Process Design Manual. Washington: United States Environmental Protection Agency. URL [Accessed: 24.08.2010].