Delhi Waste Worries and Solutions

THE CURRENT SCENARIO

Source : The Hindustan Times

The current situation of waste disposal and treatment in the capital narrates a story of utter mismanagement and unsustainability. As of  now,  to ensure proper management and disposal, the civic bodies have hired concessionaires who collect waste from door to door and segregate the waste at the site. the recyclable garbage goes to recycling sites and the rest is dumped in one of the four existing landfills. A fleet of 409 trucks are engaged in the process. However, at the ground level this system is in a state of complete chaos. The RWAs have often complained that the waste collection on a daily basis is non existent and door to door collection is just a mere illusion forcing people to dump waste in nooks and empty plots of land creating miniature landfills.

Out of all the waste generated in the capital, about 50% is fit for composting, and 30% is recyclable which leaves 20% of the waste to be dumped in the landfills. But if we give a closer look, we realise that the city generates about 9,500 tonnes of waste per day (TPD) out of which about 8,000 TPD is collected and transported to the landfills which accounts for almost 80% of the waste generated. This signals towards a huge loophole in the waste management and disposal in the capital.

According to the Master Plan for Delhi, 2021, the existing landfills    had exceeded their capacity way back in 2008 and that most of these sites have contaminated the aquifers and neighbouring groundwater reserves. As per the latest draft manual on Municipal Solid Waste Management prepared by the Union Ministry of Urban Development, Delhi requires 800 ha of land for waste disposal which would cost Rs.80,000 crores. But the city does not have enough land. According to the an assessment by the Centre of  Science and Environment, every tonne of waste disposed at the landfill will cost the MCD a sum of Rs.14,500 which is highly unsustainable.

WASTE TO ENERGY INCINERATORS

Looking at the mismanagement in the current disposal system and inefficiency of the landfills to accommodate the heavy waste generation of the capital, there is a need for an alternative solution to the menace of waste management. A waste-to-energy plant is a waste management facility that combusts waste to generate electricity. Modern waste-to-energy plants are different from the trash incinerators used earlier as they failed to remove hazardous or recyclable materials before burning.

Waste to energy generation is being increasingly looked at as a potential energy diversification strategy. The typical range of net electrical energy that can be produced is about 500 to 600 kWh per ton of waste incinerated. Generation of electricity alongwith waste management gives WTE Incinerators an edge over the existing methods of disposal.

How does a modern Waste to Energy Plant work ?

Most WTE plants burn municipal solid waste. A modern, properly run WTE plant sorts the waste before burning such that only the non recyclable materials are combusted. Waste-to-energy plants are similar in their design and equipment with other steam-electric power plants, particularly biomass plants. First, the waste is brought to the facility. Then, the waste is sorted to remove recyclable and hazardous materials. The waste is then stored until it is time for burning. A few plants use gasification, but most combust the waste directly because it is a mature, efficient technology. The waste can be added to the boiler continuously or in batches, depending on the design of the plant.

Source : http://large.stanford.edu/publications/coal/references/brat/

In terms of volume, waste-to-energy plants incinerate 80 to 90 percent of waste. Sometimes, the residue ash is clean enough to be used for some purposes such as raw materials for use in manufacturing cinder blocks or for road construction. In addition, the metals that may be burned are collected from the bottom of the furnace and sold to foundries. Some waste-to-energy plants convert salt water to potable fresh water as a by-product of cooling processes.

Pollution from a WTE plant

Waste-to-energy plants cause lesser air pollution than coal plants. They are designed to reduce the emission of air pollutants in the flue gases exhausted to the atmosphere such as Nitrogen oxides, Sulphur oxides and particulates, and to destroy pollutants already present in the waste, sing pollution control measures such as baghouses, scrubbers, and electrostatic precipitators.

 The major pollutant that comes form incinerators is fly ash and bottom ash just as in the case when coal is combusted. The fly ash amounts to about 10% to 20% of the total ash. The fly ash poses more of a potential hazard because it contains toxic metals such as lead, cadmium, copper and zinc as well as small amounts of dioxins and furans.

Currently, 3 WTE plants : Okhla-Timarpur, Ghazipur and Narela are operational in Delhi. The requirement is more such plants with greater capacity to look after the waste disposal system in our capital.

source : The Times of India

Overall, in comparison to the current system of landfills, WTE plants offer a more sustainable and eco-friendly alternative to waste management measures.