There are companies who are doing e-waste management an a commercial scale. Therefore organizations which generate a lot of e-waste must not throw the same in garbage bins but channelise the e-waste through the organizations meant for the same.

The conventional water treatment:
i) Pre-screening
ii) Aeration
iii) Sludge Management and Water Reuse.
(i) Pre-screening: Screening of waste water to remove soil and solid particulates.
(ii) Aeration: Screened wastewater is pumped to an aeration tank. Microbial contaminants are removed by the biological degradation that occurs in the presence of air.
(iii) Sedimentation process: The solid particles in suspension form are allowed to settle under the effect of gravity. The particles that settle out from the suspension is known as sludge.
(iv) Sludge removal: The sludge generated by the degradation process is transferred periodically from the tank for safe disposal.
(v) Disinfection: Chlorination and Ultra Violet (UV) radiation of treated water to remove any microorganism contamination.
(vi) Water recycling: The water will then be supplied for domestic or industrial purposes.

(i) The kinetic energy possessed by the wind is due to its high speed, that can be converted into mechanical power by wind turbines.
(ii) The wind energy can be used for
(a) Generating electricity
(b) Run water pumps, flour mills etc.
(c) Rotatory motion of windmill is used to draw water from wells.
Working of wind mills:
(i) Wind mill is a machine that converts the energy of wind into rotational energy by broad blade attached to the rotating axis.
(ii) When the blowing air strikes the blades of the windmill, it exerts force and causes the blades to rotate.
(iii) The rotational movement of the blades operate the generator and the electricity is produced.
(iv) The energy output from each windmill is coupled together to get electricity on a commercial scale.
Advantage of wind energy:
(i) Wind energy is free, eco-friendly, renewable source of energy.
(ii) It does not cause pollution.
(iii) Expenses on periodic maintenance is low when compared to the other power sources

The various devices used for harvesting sun's energy are called solar energy devices.
Solar cells:
(i) Solar cells (Photovoltaic devices) is made up of silicon that converts sunlight directly into electricity.
(ii) Solar cell produces electricity without polluting the environment.
(iii) Since it uses no fuel other than sunlight, no harmful gases, no burning and no wastes are produced. These can be installed in remote and inaccessible areas (forests and hilly regions) where setting up of power plant is expensive
Uses of Solar cells:
(i) It can be used for street lighting, traffic signals, water pumping, battery charging system etc.
(ii) It is used in artificial satellites and space probes.
(iii) It provides radio and TV transmission to remote areas
(iv) It is used in calculators, electronic toys and watches.

Biogas is the mixture of methane (nearly 75 %), hydrogen sulphide, carbon dioxide and hydrogen. It is produced by the decomposition of animal wastes (cow dung) and plant wastes in the absence of oxygen. It is also commonly called as 'Gobar gas' since the starting material used is cow dung called as gobar.
Uses of biogas:
(i) It is used as fuel for cooking.
(ii) It is used to run motors and pump sets.
(iii) It is used to generate electricity.
Advantages of biogas:
(i) It burns without smoke and therefore causes less pollution.
(ii) An excellent way to get rid of organic wastes like bio-waste and sewage material.
(iii) Left over slurry is good manure rich in nitrogen and phosphorus
(iv) It is safe and convenient to use.
(v) It can reduce the amount of greenhouse gases emitted.