Explain biological methods of waste water treatment.

Explanation

Tidal energy is the energy obtained from the movement of water due to ocean tides. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted on the oceans of the earth.
A tidal stream is a fast flowing body of water created by tides. Turbines are placed in tidal streams. When the tides hit the turbine, the turbine rotates and convents the tidal energy into electric energy.
Advantages of tidal energy:
(i) Tidal energy does not produce ant pollution.
(ii) It does not use any fuel nad does not produce any waste.
(iii) Tides are predictable, so tidal energy can be produced electricity at lower speeds than wind turbines.
Aeratin: Screened wastewater is then pumped to an aeration tank. Here the microbial contaminants are removed by the biological degradation that occure 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 knonwn as sludge.
Sludge removal: The sludge generated by the degradation process is transferred periodically from the tank for safe disposal.
Disinfectin: Chlorination and ultraviolet (UV) radiation of treated water is required to remove any microorganism cotamination.
Water recycling: The water will then be supplied for domestic or industrial purposes.