Sustainability issues in Solid Waste Management

The Project

The HAWA project, headquartered in Bangalore, in close cooperation with the Karnataka Government, the Karnataka State Pollution Control Board (KSPCB) and relevant institutions, has successfully planned and implemented the complete system for collection, transport, treatment, storage and disposal of hazardous solid waste, including co-processing options and financial implications. Know-how and technology options were transferred for the identification, minimisation, segregation and transportation of HW, the pre-treatment of it, and the construction of a state-of-the-art disposal facility. Most importantly, the institutional set up has been supported, including the roles to be played by each actor on the authorities’ side and by the industries.
Substantial results were achieved, such as a comprehensive inventory of HW generated, including prospects for the future, TSDF site selection close to Bangalore, geo-technical and hydro-geological investigation of the site, environmental impact assessment and risk analysis.
The first phase of theTSDF at Dobbaspete, near Bangalore began in June 2001. During this phase the project received technical support form GTZ for technical planning, institutional development and all other preparatory works. The second phase, the implementation phase was from June 2004 to May 2007. During the current phase, since 2007, the construction of TSDF landfill has been completed. The TSDF is operational since January 2009.
The proposed facility at Dobbasapete site is based on the conceptual design which reflects current European standards and practices which have been adapted to Indian conditions. The facility comprises of the following components:

• Waiting Area, Entrance and Security Cabin
• Weigh Bridge and Control Building
• Sampling Area
• Administration/Operation Building
• Delivery, Treatment and Storage Area
• Vehicle Washing Area for Trucks
• Disposal Facility (Engineered Landfill)
• Solar Evaporation Pond.
• Rainwater Harvesting Pond
• Workshop and Garage

All vehicles will be required to report at the security gate at the entrance, before entering the fenced facility. Incoming vehicles carrying waste will use the truck parking/waiting area which is located close to the sampling area. A designated waiting area outside the fenced area will provide parking for vehicles reaching during the night.

Vehicles will be weighed before being directed to the sampling area. The outgoing vehicles will be also checked, weighed and manifest sheet verified.

Samples of waste collected from the vehicles would be subjected to laboratory test for acceptability and given clearance accordingly. In case of non-conformity, the waste will be stored in the intractable waste shed until a decision is made after further analysis, negotiation or decision
by KSPCB.

Acceptable wastes will move to the Delivery, Treatment and Storage Area to unload the waste in the appropriate storage shed. In case, analysis indicates ‘no further treatment, storage or drying is required’, the container could be transported to the landfill area. Different acceptable wastes will be segregated in different compartments. This area will also have compartments designated for treatment and/or stabilisation of waste.

The TSDF has basic capabilities for pre-treatment of wastes prior to disposal in the secure landfill, which includes: Reduction of moisture content of sludge/semi-solid wastes by mixing with drier wastes; neutralisation of slightly acidic wastes by mixing with alkaline wastes or lime reagent and stabilisation of waste by mixing with PFA and lime or cement and lime. These activities enable the operators to minimise the hazardous nature of the wastes being landfilled, minimise leachate generation and ensure the minimum concentrations of hazardous substances in any leachate which is generated.

Landfill

The disposal facility or engineered landfill is an important element of the TSDF facility and an anticipated area of 10.8ha in the North Eastern part of the site has been earmarked for landfills, including the road and landfill dams. The cells in the landfill will be oriented in the east west direction. Each cell is designed for one year at the rate of 40000 tonnes/year. Ten cells are planned in the landfill which will be sufficient for 20 years. For daily cover for the landfill, a plastic sheet will be used. The landfill is bounded by dykes on all four sides. The base lining and surface sealing system of the landfill comprise several layers, including a compacted 1m thick clay mineral sealing layer, overlaid by an HDPE geo-membrane and protected with a non-woven needle punched HDPE geotextile which is covered with a drainage layer. The surface ceiling system on top of the landfill at the end of each construction phase controls the leachate production by reducing the ingress of rain into the fill. This system comprises a compensation layer, mineral sealing layer, geo-membrane, geotextile, drainage and re-cultivation layer.

The leachate pond is expected to evaporate the moisture during its one year cycle and the resulting sludge after evaporation will be returned to the landfill.

This landfill is specially designed to reduce leacheate generation. The technology used in this landfill has been transferred from Germany where no leachate percolation has occurred in any landfill since 1985. Other measures also include careful site selection based on geological profile, four protective layers (clay, plastic, geo-membrane and drainage) and exclusion of liquid waste and rainwater by covering it during monsoon. Waste with high moisture content will be dried before hand. If, however, there is leachate generation, it will be collected in the drainage layer and treated.

This facility has very minimal requirement of water. All used water willbe recycled and rainwater harvesting will also be implemented. Water will be drawn from the test wells (ground water monitoring wells) periodically for purposes of analysis only.

This TSDF has a multilayered sealing system at the bottom of the landfill. The landfill is mostly above the ground (a maximum of 3m below the ground). Hence, the presence of the landfill will not affect the ground water table. A ground water table at 60-90m is ideally suited for a landfill.

No smoke or smell emanates from the landfill. Also, no smelly organic liquids will be accepted.