KEY CONSIDERATIONS: The increasing awareness of public health and environmental quality concerns are expected to provide the impetus that is needed to develop and implement a sustainable approach to managing solid wastes and rehabilitation of the existing open dumps.
Although urban residents of developing countries produce less solid waste per capita than high-income countries, the capacity of these cities to collect, process or reuse and dispose solid waste is limited. The most prevalent way of disposing MSW in developing countries is open dumping. Open dumpsites pose a significant risk to public health and the environment. With few engineering measures in place, these disposal sites can contaminate groundwater and surface water, pollute the air, attract insects, vermin and other potential carriers of diseases, devalue properties and a host of other negative impacts. These disposal sites are one of the largest sources of potential pollution to the communities hosting them.
It is a matter of policy that dumpsites be closed due to the adverse effects on society and the environment. Upgrading Open Dump Sites to Controlled Disposal Facilities and further to Sanitary Landfills is a necessary step for cities to take to adopt better and environmentally sound waste disposal methods.
1. Upgrading of an Open Dump into a Controlled Disposal Facility
As with the closure of open dumpsites, upgrading into controlled disposal will require planning. A site assessment has to be conducted first in order to determine if the open dumpsite is convertible to a controlled dump. If conversion is not practical based on several criteria/considerations, a new site will have to be developed.
Development of a controlled dump on a new site has to comply with several criteria such as siting and design requirements. Because of the minimal infrastructure requirements for controlled dumps (e.g. no liner with required permeability), finding a site with suitable hydrogeologic conditions is essential. Preparation of the disposal area mainly involves the provision of adequate gradient, minimal compaction of the soil, and the construction of drainage management systems.
Conversion of an open dump into a controlled dump means that disposal will be on a site previously used for open dumping. Thus, preparation of the area will consist of leveling and compacting existing garbage heaps and construction of drainage canals/ ditches, among others.
Prescribed operational procedures include limiting the working face area, application of daily cover and miscellaneous provisions such as installation of litter barrier and others. The facility is also monitored for incoming waste volumes, water quality, condition of drainage systems, and others.
2. Shifting from Controlled Dumping to Sanitary Landfilling
This stage is the most demanding for LGUs in terms of financial resources, technology, and expertise. The development of these disposal facilities requires thorough planning and design, from its inception to its planned after use. Siting, design, construction and operation requirements are much more broad and stringent than other modes of land disposal. Sanitary landfills have the least impact to public health and the environment as compared to open dumpsites or controlled disposal facilities.
The Cost of Waste Disposal
Waste disposal cost can be categorized into capital and operating costs. The former includes costs for land acquisition, machinery and equipment, designers/consultants fees, site preparation and construction, and closure and post closure requirements. Operational costs are associated with the daily operational requirements of the facility, including salaries, maintenance costs, and others. These are generally recovered through tipping fees.
The involvement of communities impacted by a proposed project is essential to the project’s realization and success. The decision to develop waste disposal facilities is not only for a few to make but for all who will be affected by it. Thus, decision makers and planners should involve all stakeholders right from the siting process up to the facility’s post closure phase. Otherwise, there may be problems during the facility’s construction and operation, or the project may not materialize due to public opposition.
Source: United Nations Environment Programme, 2005; http://wedocs.unep.org/handle/20.500.11822/8444
CASE STUDY EXAMPLES
Dumpsite Upgradation in Kanpur, India
Kanpur, an important industrial city of Uttar Pradesh, India located at the bank of the
river Ganga, is spread over an area of 299 km2 with an estimated population of 3 million. An estimated quantity of 1000 t/day of MSW is generated from the city out of which about 700 t/day reaches the dumpsites. Panki site, presently the only active site in Kanpur, is spread over an area of 8 hectares and has been existing for the past 10-15 years. The average depth of the waste is around 4-5 m above ground level.
The New Delhi National Productivity Council was engaged by the local authorities for assistance in upgrading this dumpsite site in line with the requirements of MSW Rules.
The waste body has to be closed scientifically, which includes:
- Grading of waste
- Compaction and slopping of waste
- Drainage channel construction
- Capping consisting of clay liner, HDPE liner, drainage layer, gas vent system, top soil etc.
- Growing of vegetation cover over the top soil
- Laying of green belt at the periphery of site
The excavated area has to be developed into a scientifically designed landfill facility where the municipal waste can be disposed and managed in proper way. This includes:
- Levelling of base and side slopes of the landfill and achieving the desirable grades at the base of landfill.
- Construction of temporary embankments and surface water drains along the perimeter of the landfill.
- Laying of single composite bottom and side liner
- Installation of leachate treatment facility
- Providing infrastructure facilities at the site
- Installation of two monitoring wells at the up gradient and three at down gradient
Dumpsite Rehabilitation in Pune, India
The city of Pune generates approximately 1000 tons MSW per day. Like most of the
other municipalities in India, the Pune Municipal Corporation (PMC) has been resorting to dumping of the MSW in open land and abandoned quarries. One such site is in the village of Uruli Dewachi, about 5-6 km beyond PMC limits off Saswad road. The site was originally a stone quarry and had deep excavated areas. The daily waste coming to the site is about 750 tons/day (TPD). Dumping at this site was in progress to full capacity since 2002. When serious ground water contamination was observed in wells on the down stream slopes up to 2 km away from site, the PMC adopted a strategy of rehabilitating the dumpsite by capping and construction of a sanitary landfill over the capped site.
The task of rehabilitating the dumpsite was undertaken by M/s. Eco Designs India Pvt. Ltd., Pune in February 2002. After all the preliminary data were collected, the landfill was designed as per the MSW 2000 rules. The design included the following tasks:
- Closure/capping of the existing dumpsite;
- Design of a landfill above the capped waste, with a volume to handle waste for a period of one year; and
- Design of a landfill adjacent to the capped waste, with a volume to handle waste for a period of 5 years.
The waste had been randomly deposited without any spreading or compaction. A
preliminary inspection found that the waste heap was very unstable primarily because of the face angle of the waste, which was in excess of the stable angle of repose. It was therefore necessary to change the slopes as well as compact the waste, so that it would be permanently stable. The waste was evenly spread out and compaction was carried out on the slopes and the top by using heavy duty bulldozers. The closure covered an area of about 34,600 m2. The height of waste was as much as 18 m at the edge after proper leveling.
Once the waste was graded and compacted, a 0.75 mm thick Very Flexible Polyethylene (VFPE) liner was installed above it to avoid ingress of rain water. This was protected with a geotextile overlaid by 300 mm thick soil layer. The soil layer was finally covered with sweet earth for planting of grass, which would prevent erosion of the cover soil. Drains were provided on the slopes so that the storm water could be drained and collected at the bottom, where a gutter along with a toe wall was provided. Gas vents were provided to allow for the release of gases that could be potentially formed within the covered landfill.
The capped landfill had a top plain surface area of about 18,500 m2. The cost of
dumpsite closure was Rs.10, 080,000 (about US $ 0.2 million). PMC had no other
acquired land on which to develop a new landfill facility. It had started composting the organic waste and was still generating large amounts of waste to be landfilled. Hence it was decided that until a larger landfill was constructed in the adjoining property, a smaller landfill would be constructed over the capped waste. This served the purpose of not only buying some time until the new facility was built, but also in developing some confidence about being able to build and operate a sanitary landfill. The construction of the landfill has now been completed and is in operation.
Community-based Waste Management Programs
Community-based waste management programs are collaborations between NGO’s, government agencies and impacted communities, to provide the equipment, resources and training necessary to establish an effective waste management program and to run the program independently. Visit Best to learn more.