31. Differentiate between asexual and sexual reproduction in plants.
32. Describe how the following are used during wastewater treatment.
a) Grit tank
b) Settling tank
c) Aeration tank
d) Chemical treatment tank
Answers
Answer:
32. d) chemical treatment tank
Answer:
31. Asexual reproduction
1. It occurs in lower invertebrates and lower chordates and plants with simple organisations.
2. It is always uni-parental
3. No fertilization.
4. Offspring is normally similar to the parent.
5. No gametes are formed.
Sexual reproduction
1. It occurs in all types of animals and mostly higher in plants
2. It is usually bi-parental.
3. Fertilization takes place.
4. Offspring shows the variation with respect to the parent.
5. Gametes are always formed.
32.
a)Grit settles by gravity into the bottom of the tank (in a grit hopper) while effluent exits at the top of the tank. The grit that settles into the grit hopper may be removed by a grit pump or an air lift pump.
b)Sedimentation tank, also called settling tank or clarifier, component of a modern system of water supply or wastewater treatment. ... A sedimentation tank allows suspended particles to settle out of water or wastewater as it flows slowly through the tank, thereby providing some degree of purification.
c)Aeration provides oxygen to bacteria for treating and stabilizing the wastewater. Oxygen is needed by the bacteria to allow biodegradation to occur. The supplied oxygen is utilised by bacteria in the wastewater to break down the organic matter containing carbon to form carbon dioxide and water.
d)The discussed chemical wastewater treatment processes include chemical precipitation (coagulation, flocculation), ion exchange, neutralization, adsorption, and disinfection (chlorination/dechlorination, ozone, UV light).