players, calculators, toys, sport equipments, etc. Household electrical appliances: Refrigerators, washing machine, microwave oven, mixer, grinder, water heater, etc. Accessories: Printing cartridges, batteries and chargers. Environmental impact of e-wastes Disposal of any kind of electrical and electronic devices without knowledge can become the landfill and water pollutants.
E-wastes include Computer components - % Telecommunication components - % Electronic components - % Biomedical components - % Other components - % More to Know Health Effects of E- Wastes Lead : Damages central and peripheral nervous system; affect brain development in children Chromium : Asthmatic bronchitis Cadmium : Accumulates in kidney and liver; neural damage Mercury : Chronic damage to brain and respiratory system Plastics including Polyvinyl Chloride (PVC) : Burning produces dioxin which can cause developmental and reproductive problems, damages the immuns system. Electronic equipments contain many hazardous heavy metals such as lead, cadmium that can cause severe soil and groundwater pollution. E-waste dumping yards and the places nearby are polluted and cause severe health hazard. .
Sewage Management Untreated sewage or wastewater generated from domestic and industrial process is the leading polluter of water sources in India. Sewage water results in agricultural contamination and environmental degradation. Sources of Sewage/wastewater Domestic purpose or household activities Dye and textile industries Leather industries Sugar and breweries industries Paper and pulp industries Figure . A view of sewage treatment plant Sewage/wastewater treatment method The conventional wastewater treatment methods involve the following steps (a) Pre-screening (b) Aeration (c) Sludge Management and (d) Water Reuse.
Pre-screening : Wastewater generated from domestic and industrial activities is screened to remove soil and solid particulates. Aeration : Screened wastewater is then pumped to an aeration tank. Here the microbial contaminants are removed by the biological degradation that occurs in the presence of air. Sedimentation process : In this process, the solid particles in suspension form are allowed to settle.
The particles that settle out from the suspension is known as sludge. Sludge removal : The sludge generated by the degradation process is transferred periodically from the tank for