solution finder

27 April 2018

Landfills

Author/Compiled by
Beat Stauffer (seecon international gmbh)
Executive Summary

A landfill is an engineered pit, in which layers of solid waste are filled, compacted and covered for final disposal. It is lined at the bottom to prevent groundwater pollution. Engineered landfills consist of a lined bottom; a leachate collection and treatment system; groundwater monitoring; gas extraction (the gas is flared or used for energy production) and a cap system. The capacity is planned and the site is chosen based on an environmental risk assessment study (UNEP 2002). There are also landfills specially designed to encourage anaerobic biodegradation of the organic fraction of the waste for biogas production by monitoring the oxygen conditions and moisture content. Landfills need expert design as well as skilled operators and a proper management to guarantee their functionality.

Advantages
Effective disposal method if managed well
Sanitary disposal method if managed effectively
Energy production and fast degradation if designed as a bioreactor landfill
Disadvantages
Fills up quickly if waste is not reduced and reusable waste is not collected separately and recycled
A reasonably large area is required
Risk of groundwater contamination if not sealed correctly or the liner system is damaged
High costs for high-tech landfills
If not managed well, there is a risk of the landfill degenerating into an open dump
Once the landfill site is shut down O&M and monitoring must continue for the following 50 to 100 years
In Out

Faecal Sludge, (In-)Organic Solid Waste

Non-biodegradable Wastewater, Biogas, Energy

Factsheet Block Title
Introduction
Factsheet Block Body

A landfill, also called sanitary landfill, is a land disposal site for waste, which is designed to protect from environmental pollution and health risks. It is not the same as an open dump. Landfills are built to concentrate the waste in compacted layers to reduce the volume and monitored for the control of liquid and gaseous effluent in order to protect the environment and human health.
Besides municipal solid waste, faecal sludge can also be discharged into landfills. Well-constructed and maintained landfills are safer than open dumping sites, but even the best sanitary landfill will fill up and, after many years, probably start to leak. Therefore only waste, which cannot be reused further should be disposed of in landfills. To solve current waste problems, prevention of waste in the first place remains a priority. Separation of different types of wastes and reuse is much more sustainable. For instance, the disposal of faecal sludge should only be considered, if there is no need and market for soil conditioner/ fertiliser (see also composting large-scale and small scale, fertiliser from sludge, anaerobic digestion and use of compost).

Factsheet Block Title
Treatment Process and Basic Design Principles
Factsheet Block Body

 A typical schematic design of an engineered landfill with a full leachate and gas management. Source: UNEP (2002

A typical schematic design of an engineered landfill with a full leachate and gas management. Source: UNEP (2002)

A basic landfill is a pit with a protected bottom (to prevent contamination of groundwater) where trash is buried in layers, compacted and covered. Ideally, about 0.5 m of soil should cover the deposited refuse at the end of each day to prevent animals from digging up the waste, flies from breeding and to avoid that odour, waste (e.g. plastic bags) or pathogens are spread by the wind (see also HARVEY et al. 2002 Chapter 7.7.1).
The more advanced (“engineered”) landfills consist of a liner system at the bottom and the sides; a leachate removal system, which also includes a treatment of the leachate; groundwater monitoring, gas extraction (the gas is flared or used for energy production) and a cap system (see picture above). The capacity is planned and the site is chosen based on an environmental risk assessment study (UNEP 2002).


There also types of aerobic or anaerobic bioreactor landfill. Bioreactor technology accelerates the biological decomposition of the organic fraction of the waste (e.g. food, plants, paper, etc.) in a landfill by promoting conditions necessary for the microorganisms that degrade the waste and produce biogas. The single most important factor in promoting waste decomposition is the moisture content of the waste. Liquids must be added to the waste mass to obtain optimal moisture content, which ranges from 35 to 45 percent water by weight. Liquids that are added include: the landfill leachate that is previously recovered at the bottom, gas condensate, water, storm water runoff, and faecal sludge or residual sludge from wastewater treatment plants (adapted from WM 2004).

   This picture shows an engineered landfill, which was designed for the production of gas through anaerobic digestion. In the anaerobic conditions of the engineered landfill (“anaerobic bioreactor”) the degradation of the organic fraction of the waste is accelerated by optimising the moisture content by the addition of a source of moisture (e.g. sewage sludge). The collected gas generates electrical energy. Source: WM (2004)

This picture shows an engineered landfill, which was designed for the production of gas through anaerobic digestion. In the anaerobic conditions of the engineered landfill (“anaerobic bioreactor”) the degradation of the organic fraction of the waste is accelerated by optimising the moisture content by the addition of a source of moisture (e.g. sewage sludge). The collected gas generates electrical energy. Source: WM (2004)   


Treatment of Leachate

Landfill leachates will cause environmental problems if not handled properly. One of the most promising methods of treating landfill leachate are constructed wetlands as they require little operation and maintenance (see also horizontal flow, vertical flow, free-surface and hybrid constructed wetlands). The use of constructed wetlands to treat landfill leachates is an environmentally sustainable and cost saving solution (see also SA'AT 2006).

Factsheet Block Title
Cost Considerations
Factsheet Block Body

Because building and maintaining a sanitary landfill is a lot of work, it usually needs to be done in partnership with the community, local government, and other organisations, such as churches or businesses (CONTANT and FADEM 2008). Sanitary landfill is the most cost-effective system of solid waste final disposal for most urban areas in developing countries (COINTREAU 2004). If there is no other solution (e.g. separate collection and separate recycling/incineration), landfills are an effective way to discharge solid waste or residual sludge from wastewater treatment plants. With a properly planned landfill it is possible to prevent groundwater contamination and to collect biogas for further use. High-tech landfills, such as bioreactor landfills, will be more expensive in initial costs as well as O&M costs.

Factsheet Block Title
Operation and Maintenance
Factsheet Block Body

A landfill requires a dedicated operator to ensure the management procedures above are carried out (UNEP 2002). Waste has to be covered each day as already described above. Once the capacity of the landfill is reached, it has to be covered correctly and the bottom has to be controlled regularly to make sure no toxic effluent reaches groundwater sources. The cover should resist erosion by wind and water, promote vegetation and satisfy aesthetic, ecological, or end use criteria (GROSS n.y.).
The bioreactor landfill including anaerobic digestion and addition of moisture as described above requires a much higher level of maintenance and operator skill to optimise operations and to modify the system as needed. Consequently, bioreactor landfills require a more complex set of operations and maintenance (O&M) procedures than conventional landfills. Additionally, liquid delivery systems must be designed and installed at various stages of landfill operation. They increase the risk of damage to the liquid delivery system and add to the complexity of conducting day-to-day operations. Therefore, some waste disposal facilities, with limited resources, may find it difficult to retain the appropriate level of design, construction, and operator skills to successfully implement a bioreactor landfill project (adapted from ITRC 2006).

Factsheet Block Title
Health Aspects
Factsheet Block Body

Open dumps can be turned into sanitary landfills. Or a community can build a new sanitary landfill and clean up the old site by transporting trash to the new one. A sanitary landfill protects community health when (CONTANT and FADEM 2008):

 

  • It is built away from where people live.
  • It is covered to prevent insects and other disease-carrying animals from breeding.
  • It has a lining of hard-packed clay soil and/or plastic to prevent chemicals and germs from contaminating groundwater.

 

A landfill protects community health only if it is well managed. Good management includes training and support for landfill workers, and working together with resource recovery centres, toxic waste collectors, and local government (CONTANT and FADEM 2008).

Factsheet Block Title
At a Glance
Factsheet Block Body

Working Principle

Municipal solid waste (MSW) and faecal sludge are discharged in a lined and sealed landfill. At the end of each day it must be covered with soil. It is a pit in which trash is buried in layers, compacted and covered.

Capacity/Adequacy

It can be applied for small communities and big cities. As long as it is constructed and operated correctly, the risks to human health and the environment are low.

Performance

Bad if just a basic landfill, good if a engineered landfill.

Costs

A landfill is not the perfect solution but still one of the cheapest for developing countries and rural areas.

Self-help Compatibility

Engineered landfills need expert design and skilled operators.

O&M

A landfill must be managed properly to reduce any risks to the environment. Therefore skilled workers are required.

Reliability

Mostly reliable, but risks of leaching remain.

Main strength

An effective disposal method if managed well.

Main weakness

Mismanagement can lead to environmental pollution.

Applicability

Landfilling is one of the most widely employed methods for the disposal of municipal solid waste (SA’AT 2006). It is applicable where enough land is available and costs are lower than other discharge methods. Depending on the capabilities of the community/city (financial, knowledge), a very basic landfill can be designed or a high-tech bioreactor landfill implemented. However, it must always be lined properly at the bottom to prevent groundwater pollution and a cover is needed to protect from insect breeding or wind erosion.

Media PPT
Library References

A Community Guide to Environmental Health

A comprehensive Guidebook to Environmental Health that helps promoters, development workers, educators, activists and community leaders take charge of their communities´ environmental health. Published by Hersperian Foundation the editors of the rural health bible “Where there is no Doctor”

CONANT, J. FADEM, P. (2008): A Community Guide to Environmental Health. Berkeley, CA: Hesperian Foundation URL [Accessed: 25.04.2019]

Emergency Sanitation: Assessment and Programme Design

This book has been written to help all those involved in planning and implementing emergency sanitation programmes. The main focus is a systematic and structured approach to assessment and programme design. There is a strong emphasis on socio-cultural issues and community participation throughout.Includes an extensive “guidelines” section with rapid assessment instructions and details on programme design, planning and implementation.

HARVEY, P. BAGHRI, S. REED, B. (2002): Emergency Sanitation: Assessment and Programme Design. Loughborough: Water, Engineering and Development Centre (WEDC) URL [Accessed: 21.02.2011]

Characterisation, Design, Construction, and Monitoring of Bioreactor Landfills. Technical/Regulatory Guideline

This Bioreactors Landfill Technical/Regulatory Guidance Document is primarily written for decision makers associated with the planning, development, review, and implementation of bioreactor landfills. The decision makers include, at a minimum, regulators, owners/operators, and consultants. This document focuses on the decisions related to design, evaluation, construction, and monitoring associated with bioreactor landfills.

ITRC (2006): Characterisation, Design, Construction, and Monitoring of Bioreactor Landfills. Technical/Regulatory Guideline. Washington, DC: Interstate Technology & Regulatory Council URL [Accessed: 16.11.2011]

Subsurface Flow and Free Water Surface Flow Constructed Wetland with Magnetic Field for Leachate Treatment

This study conducted using two-stage lab-scale Subsurface Flow (SSF) and Free Water Surface (FWS) constructed wetland under influence of magnetic field to treating the leachate. Furthermore it includes a general description about the constructed wetland systems free water surface flow and subsurface flow.

SA’AT (2006): Subsurface Flow and Free Water Surface Flow Constructed Wetland with Magnetic Field for Leachate Treatment. Johor Bahru: University Teknologi Malaysia URL [Accessed: 23.08.2011]

A Directory of Environmentally Sound Technologies for the Integrated Management of Solid, Liquid and Hazardous Waste for Small Island Developing States (SIDS) in the Pacific Region

This directory is part of UNEP collaboration with SIDS on the implementation of the Waste Management chapter of the Barbados Programme of Action. It focuses primarily on proven sound environmental technologies for solid, liquid and hazardous waste management plus those currently successfully being used in SIDS within the Pacific Region.

UNEP (2002): A Directory of Environmentally Sound Technologies for the Integrated Management of Solid, Liquid and Hazardous Waste for Small Island Developing States (SIDS) in the Pacific Region. The Hague: United Nations Environment Programme (UNEP) URL [Accessed: 28.03.2012]

The Bioreactor Landfill

This brochure was prepared to share the vision of WASTE MANAGEMENT of the future of landfill management and to describe their steps to realise this vision.

WM (2004): The Bioreactor Landfill. Cincinnati: Waste Management (WM) Bioreactor Programm URL [Accessed: 16.11.2011]
Further Readings

A Community Guide to Environmental Health

A comprehensive Guidebook to Environmental Health that helps promoters, development workers, educators, activists and community leaders take charge of their communities´ environmental health. Published by Hersperian Foundation the editors of the rural health bible “Where there is no Doctor”

CONANT, J. FADEM, P. (2008): A Community Guide to Environmental Health. Berkeley, CA: Hesperian Foundation URL [Accessed: 25.04.2019]

Landfill Design and Operation

Disposal sites, the final links in the waste handling chain, are usually transfer stations and sanitary landfills. This document contains a general description, as well as siting and operation advices and a description of the different designs and types of landfills.

GOVERNMENT ENGINEERING (2006): Landfill Design and Operation. In: Government Engineering – The Journal for Public Infrastructure: , 38-42. URL [Accessed: 16.11.2011]

Emergency Sanitation: Assessment and Programme Design

This book has been written to help all those involved in planning and implementing emergency sanitation programmes. The main focus is a systematic and structured approach to assessment and programme design. There is a strong emphasis on socio-cultural issues and community participation throughout.Includes an extensive “guidelines” section with rapid assessment instructions and details on programme design, planning and implementation.

HARVEY, P. BAGHRI, S. REED, B. (2002): Emergency Sanitation: Assessment and Programme Design. Loughborough: Water, Engineering and Development Centre (WEDC) URL [Accessed: 21.02.2011]

Characterisation, Design, Construction, and Monitoring of Bioreactor Landfills. Technical/Regulatory Guideline

This Bioreactors Landfill Technical/Regulatory Guidance Document is primarily written for decision makers associated with the planning, development, review, and implementation of bioreactor landfills. The decision makers include, at a minimum, regulators, owners/operators, and consultants. This document focuses on the decisions related to design, evaluation, construction, and monitoring associated with bioreactor landfills.

ITRC (2006): Characterisation, Design, Construction, and Monitoring of Bioreactor Landfills. Technical/Regulatory Guideline. Washington, DC: Interstate Technology & Regulatory Council URL [Accessed: 16.11.2011]

Fecal Sludge Management in Developing Countries - A Planning Manual

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.

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]

Subsurface Flow and Free Water Surface Flow Constructed Wetland with Magnetic Field for Leachate Treatment

This study conducted using two-stage lab-scale Subsurface Flow (SSF) and Free Water Surface (FWS) constructed wetland under influence of magnetic field to treating the leachate. Furthermore it includes a general description about the constructed wetland systems free water surface flow and subsurface flow.

SA’AT (2006): Subsurface Flow and Free Water Surface Flow Constructed Wetland with Magnetic Field for Leachate Treatment. Johor Bahru: University Teknologi Malaysia URL [Accessed: 23.08.2011]

A Directory of Environmentally Sound Technologies for the Integrated Management of Solid, Liquid and Hazardous Waste for Small Island Developing States (SIDS) in the Pacific Region

This directory is part of UNEP collaboration with SIDS on the implementation of the Waste Management chapter of the Barbados Programme of Action. It focuses primarily on proven sound environmental technologies for solid, liquid and hazardous waste management plus those currently successfully being used in SIDS within the Pacific Region.

UNEP (2002): A Directory of Environmentally Sound Technologies for the Integrated Management of Solid, Liquid and Hazardous Waste for Small Island Developing States (SIDS) in the Pacific Region. The Hague: United Nations Environment Programme (UNEP) URL [Accessed: 28.03.2012]

The Bioreactor Landfill

This brochure was prepared to share the vision of WASTE MANAGEMENT of the future of landfill management and to describe their steps to realise this vision.

WM (2004): The Bioreactor Landfill. Cincinnati: Waste Management (WM) Bioreactor Programm URL [Accessed: 16.11.2011]

Faecal Sludge Management. Lecture Notes

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.

EAWAG/SANDEC (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]

Sludge Treatment and Disposal

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.

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

Wastewater and Landfill Leachate Treatment Plant for the Municipality of Centar Župa

This paper presents the results of the analyses of the wastewater quantities and constituents from the Centar Župa municipality and leachate quantities and leachate composition, mass loading from the wastewater and also from the leachate. Total wastewater quantities and total wastewater flow pollutant concentrations have been calculated. Results of the calculations of the wastewater treatment structures are presented in the paper.

PELIVANOSKI, P. DONEVSKA, K. SOFRONIEVSKA. D. (2009): Wastewater and Landfill Leachate Treatment Plant for the Municipality of Centar Župa. Ohrid: International Symposium on Water Management and Hydraulic Engineering URL [Accessed: 16.11.2011]
Training Material
Awareness Raising Material

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