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Lecture
Model Answers to Learning Activities
LEARNING ACTIVITY 4.
Based on a general observation, some of the constraints municipal authorities in our locality face with regard to effective waste disposal include poor political back up, inadequate infrastructure, insufficient funds and lack of public support. Let me explain these below:
(i) Waste disposal is as much a technical issue as a political one. For example, an elected representative, called a Corporator, administers a municipal ward, and is responsible for the general upliftment of the ward. But, generally, waste disposal is not considered a priority issue. However, our locality, and indeed, Bangalore is just awakening to the importance of waste disposal, and the Bangalore Agenda Task Force appointed by the State government has introduced a programme called the Swachha Bangalore. This programme involves door-to-door collection of solid waste. But, this is merely a temporary solution as the city, requires an integrated waste management system. In the main, for any programme to be successful, sufficient political and governmental backing is necessary.
(ii) In our locality, importance is given to waste collection and not waste disposal. Due to the inadequate infrastructure, the municipality is unable to give sufficient importance to waste disposal. (iii) Waste disposal is a costly process and sufficient funds are not available to the municipality to adopt latest techniques such as pyrolysis, gasification, etc.
(iv) Public support is essential for the success of any waste management programme. For example, people must stop dumping wastes indiscriminately on roadsides and in drains. Indiscriminate dumping makes waste collectors’ work tedious and time consuming.
LEARNING ACTIVITY 4.
Based on technical (i.e., composition of waste, existing practices and technology), social (i.e., health and income implication, and public opinions) and environmental (i.e., initial and long-term environmental risks) aspects, the best disposal option for our locality is composting. This is due to the fact that our locality is predominantly residential, generating mostly biodegradable wastes, and composting does not need long-term maintenance. Nor does it cause any adverse environmental effects.
LEARNING ACTIVITY 4.
No, a sanitary landfill is not possible to manage wastes in our locality mainly because:
it is not economically feasible for a small locality such as ours; composition of waste is mostly biodegradable; sufficient land is not available for setting up a landfill site.
LEARNING ACTIVITY 4.
Typical landfill gases include methane, carbon dioxide, oxygen and nitrogen, and these adversely impact on public health and the environment. For example:
Methane is flammable in air and can lead to unpredictable and uncontrolled subsidence and production of smoke and toxic fumes. Trace components such as aldehydes, alcohol and esters are toxicants when present in air at concentrations above occupational exposure standards. The landfill gases lead to global warming as these absorb reflected solar radiations.
It is vital that these emissions are controlled, and we can achieve this by controlling:
waste inputs (i.e., restrict the amount of organic wastes);
Uncontrolled disposal is a non-engineered waste disposal method in which wastes are dumped at a designated point without any environmental control, and it (i) causes odour problems due to the putrification of biodegradable wastes, (ii) provides a breeding place for disease vectors such as flies, mosquitoes, etc, and (iii) causes visual pollution, etc.
When properly managed, a landfill is a better and safer option of disposing wastes than uncontrolled dumping. Also, it is adaptable to all kinds of wastes and there is potential for by- product recovery.
LEARNING ACTIVITY 4.
Landfill is a complex reactor where physical, chemical and biological processes transform polluting wastes into environmentally acceptable deposits. Due to the complexity of these processes and their potential environmental effects, monitoring is needed to confirm that the landfill works as expected. Knowledge of the chemical composition of leachate and gas is required, as leachates may contain toxic substances and, if not prevented, may contaminate the groundwater. Landfill gases that may be flammable, asphyxiating and noxious, pose a health hazard. A continued groundwater-monitoring programme is essential for confirming the integrity of the liner system.
