1. In wet oxidation processes an increase in oxidation is due primarily to reacting the sludge with greater quantities of oxygen at elevated temperatures and pressures. 135
a. true
b. false

2. Chemical stabilization of sludge finds application at over loaded plants and at plants experiencing stabilization facility upsets.
a. true
b. false

3. Sludge should be thickened as much as possible in order to minimize digestion time in aerobic digesters.
a. true
b. false

4. If gasification problems develop in a gravity thickener as a result of excessive sludge retention times the rate of sludge withdrawal should be increased so as to lower the sludge blanket depth with a subsequent lowering of the sludge retention time.
a. true
b. false

5. Primary sludge has a specific gravity closer to that of water than secondary sludge.
a. true
b. false

Answers:

1. b
2. b
3. a
4. a
5. b