Many low income country municipalities, non-governmental organization (NGO)-sponsored entities and company-operated landfills are closing or planning closure for existing unlined open dumps and landfills. The municipalities are planning new lined landfills with leachate collection and treatment, and in some cases landfill gas collection for eventual gas-to-energy projects. One key mechanism for ensuring new landfill operational success is to develop an interim design and operational approach for the existing landfill. The approach is an intermediate or transitional approach that incorporates improved landfilling practices, enables the existing landfill to be operated to a higher standard, and initiates the operational “paradigm shift” necessary to successfully operate the new landfill.

Current Landfilling Trends

While engineered landfills are an increasing percentage of low income country landfills, the majority of landfills are non-engineered. Non-engineered landfills in low income countries are generally operated under two paradigms: large landfills are operated as open dumps on which waste is heaped high without following a specific plan or approach; smaller landfills are operated as open dumps or with a trench-and-fill/low area fill method. Under the second paradigm, local authorities and operators typically do not envision placing waste above grade; a number of countries’ regulations specifically prohibit placing waste above grade. It is clearly a big leap to go from operating under these paradigms to operating an engineered, lined landfill with a leachate collection system. Thirty years were required for high income countries to transition from open and burn dumps to modern, lined landfills with leachate and gas collection; low income country landfill operators need to incorporate improved practices over time as well in order to ensure success. The World Bank, among other organizations, has been instrumental in identifying low income country landfilling trends and has provided assistance to municipalities to improve their operations. The following link provides a good summary of worldwide low income country landfilling trends:

http://www.worldbank.org/urban/solid_wm/erm/CWG%20folder/uwp3.pdf

Successful Case Study

A client of Environmental Resources Management initiated a waste management strategy for the area under its responsibility in the early 2000’s, which includes small communities within an approximately 13,000 square kilometer area. The strategy included developing more regional, engineered, lined landfills with leachate collection systems. These new landfills were sited at new locations that met established siting criteria. Parallel with strategy development and execution, improvements were planned and executed on an existing landfill to ensure the landfill is operated in significant accordance with modern landfill practices. The primary objectives of the landfill improvements included the following:

• Hydrogeological isolation; waste was previously placed below grade, often within the seasonal high groundwater level; additionally, stormwater often drained to and pooled in refuse;
• Formal engineering preparation for the interim fill area, including design (base grade plans and sections), operation (lift development plans and a final fill plan), and closure (preliminary closure plans);
• Permanent control and staffing; and
• Planned waste placement and covering.

The above improvements, which included classroom and onsite operations training, were subsequently executed by the client. The interim landfill design included improvements to the entire landfill site area, and future waste placement in a “land vault” over a small portion of the site for the five year interim operating period. The land vault was designed such that all waste was placed above grade, with side and top deck slopes, daily and interim cover, grading and drainage improvements and other engineered features typical of modern landfills with waste placed above grade. However, the land vault was not lined and did not include leachate collection. Now that the plan has been executed for five years and the land vault is nearing its final design elevations, the success of the project is clearly evident. Drainage improvements effectively move stormwater from the site, minimizing the impact of stormwater on waste. Vegetation growth is abundant in areas that were previously heavily eroded and denuded. Waste placement at the designated area and in accordance with the operating guidelines has substantially reduced the landfill operation’s risk to the nearby community. The before and after photos of an eroded drainage and of waste placement demonstrate the improvements’ success.

The landfill operations improvements presented a unique opportunity for the client and its contractors to learn more modern landfill practices. While new lined landfill operation will provide additional challenges, including leachate handling and liner operations awareness, the transitional operations lessons learned provide a good basis upon which the client and its contractors can successfully operate the new facilities.

About the Author

Susan Rankin is a Registered Geologist and Registered Civil Engineer at Environmental Resources Management (ERM) in Sumatra, Indonesia. She has 16 years of experience in the environmental industry, both as a consultant and a client in industry and government. Susan primarily serves a key client’s site assessment, remediation and waste management needs. She was previously a seconded environmental engineer in the Joint Operation (JO) organized to produce the oil fields in the Divided Zone between Kuwait and Saudi Arabia. Susan’s experience also includes four years of environmental consulting in California, U.S.A. and five years as a California Waste Management Department engineer in one of the largest counties in California.

Photographs: Courtesy of Susan Rankin, Sumatra, Indonesia.