Underlying the flooding and Guru-jam of July 2016, the leachate pond at the Bandhwari waste dump in the monsoon, and the spike in air pollution post Diwali in November 2016, is our lifestyles and technologies that generate massive amounts of waste that choke our water ways, poison our groundwater, and pollute our air.
Gurgaon has very high air pollution levels, surely a perverse achievement for the fastest growing city in the NCR. In short, our waste impacts our water, or soil and our air. Surely we can do better.
Municipal solid waste, generally referred to as ‘garbage’, predominantly consists of waste from individual houses. In the default business-as-usual scenario, the several waste streams of solid waste mingle together in an unholy mess that is difficult to treat and recycle, and is often dumped locally, burnt, or dumped in informal landfills. The diagram on the next page shows the default scenario and its attendant outcomes on air and water pollution.
Open burning of waste causes local air pollution as well as contributes to global warming and climate change. It releases fine particulate matter (PM2.5 and PM10) a short term climate pollutant, and carbon dioxide which has a longer climate impact. Other gases depend on what is burnt – mixed waste could release toxins like dioxins and other pollutants.
Dumping waste in unmanaged landfills leads to release of methane, a short-lived climate pollutant, from anaerobic decomposition, and also increases ground-level ozone, thereby contributing to both air pollution and climate change.
Landfills also generate leachate from water that has percolated through the waste. Leachate is a cocktail of pollutants and can include heavy metals. In unmanaged landfills, leachate contaminates the groundwater and flows on the surface and contaminates local water bodies. This damages the local ecosystem such that vegetation is unable to survive as has been seen at Bandhwari defacto landfill.
Open dumping of waste, particularly plastics, in drains or water bodies cause choking of these systems, such that water is unable to percolate through the earth, thereby reducing recharge of groundwater and increases flooding risk.
Waste pickers manually search through mixed waste for recyclable items, exposing themselves to all kinds of hazards, which threatens their health and lowers their dignity.
In contrast, in a sustainable waste management scenario, when waste is reduced, segregated, recycled, etc., then both air and water pollution is reduced. This requires steps at multiple stages, from home to colony, to city and beyond.
Segregated waste at the point of origin in the household is the key element here. In a residential colony, biodegradables from every household would be collected and composted along with horticultural residues. Bio-methanation is another alternative that could be adopted. The recyclables would be sold or given to recycling plants through organised waste collectors. Thus, the volume of waste being generated for disposal in landfill would be a small fraction as opposed to the earlier default scenario. Managed landfills would thus be smaller and last longer and would have effective leachate management that prevents groundwater contamination and also capping mechanism to capture and utilise methane.
Other broader polices would include banning plastic bags and promoting reusable shopping bags, reducing extent of packaging waste, organising waste collectors and recyclers.
In addition, to garbage, another waste stream of domestic households is that of liquid waste i.e. waste water from kitchens, baths, and toilets. Untreated, pollutes water ways and ponds, and can impact groundwater quality.
With minimal open dumping and open burning of garbage, there would be less contribution to air pollution and climate change, and less impact on water bodies, better groundwater recharge, lowered flooding risk, and clean green spaces that invite recreational activities.
Recognising the environmental pollution burden of unmanaged waste can be a motivating factor for action and thereby reduce the pollution burden. This should be accompanied by basic assessment of the baseline pollution scenario, to subsequently assess the positive impact of improved waste management measures