Unlike other Indian states and countries,over 7,000 tonnes of Delhis waste is either recycled or send to landfill sites. Incineration of waste,a method adopted by most countries,is usually not possible in Delhi due to the states unique waste composition (which has very high moisture content),say experts.
Incineration or thermal treatment is a technology for waste management that involves burning of organic material at a high temperature. The process,which converts waste into heat energy,can then be used to generate electric power.
According to environmentalists,the incineration process in India and in other parts of the world,is usually carried out at low temperatures probably to save fuel (particularly in Delhi) resulting in high toxic emissions.
A study reveals that municipal waste incinerators produce the highest amount of dioxin air emissions.
Wastes such as plastic,metal and glass constitute non-biodegradable substances. These everyday substances when disposed at land-fills block the penetration of water into the soil thereby affecting plant growth. When burnt,plastic releases cancer-causing dioxins. Plastic dumped in water can also cause water-logging which then becomes a breeding ground for vectors that spread diseases like cholera. Presently in Delhi,2,800 tonnes of non-biodegradable substances are dumped every day.
Discarded or old electronic waste or devices such as computers,mobile phones and televisions constitute E-waste. Environmentalist Ravi Aggarwal says,There are over 50 toxins in a computer and this requires proper processing because if not adhered to,electronic scraps containing lead and mercury apart from other chemicals,can lead to serious health hazards. E-waste amounts to 12,000 tonnes a year in Delhi. Unsafe exposure to recycling operations and leaching of heavy metals can acutely affect workers.
Environment and Health Issues of Waste and its Disposal,a study by Toxiclinks,reveals that 1 gram of mercury can contaminate a 20-acre lake. Mercury and chemicals from other materials,such as tubelights,percolate into water and soil. This can then produce new chemicals that can cause cancer and other deadly diseases. These chemicals also enter human body in indirect way,such as through fish or milk. Medical waste amounts to 60 tonnes a day in the city.
While many believe that bio-degradable products such as manure,plant and animal waste is safe and good for soil fertility,proper waste management system is the key to processing of this waste. If not supervised properly,these wastes get broken down into biogas containing methane. This then becomes a potent greenhouse gas which leads to global warming. In Delhi,bio-degradable waste amounts to 4,200 tonnes a day.
Reporter is a student of EXIMS