Environmental Biotechnology答案2023秋

第七章测试

1.Advantages of anaerobic treatment include ( ) .
A:Produce useful end products.
B:Low production of waste biological solids.
C:High organic loading is possible.
D:High removal efficiency with dilute wastes.

答案:ABC
2.The successful start-up and operation of an anaerobic system requires: ( ).
A:Begin with as much good anaerobic seed as possible.
B:Bring the system to temperature.
C:Fill the digester with seed and water.
D:Add buffering material in the form of chemical to protect against pH drop.
3.Possible methods to control toxicity in anaerobic treatments: ( ).
A:The toxicity of some heavy metals can be removed by addition of sulfide.
B:The toxicity of long-chain fatty acids can be reduced by calcium.
C:Maintaining a lower pH can reduce ammonia toxicity.
D:The toxicity of sulfide can be reduced by gas stripping from the reactor.
4.Which of the following statements is false about the characteristics of baffled reactor: ( ).
A:Wastewater moves upward and downward.
B:Design loading typically is in the range of 4 to 15 kg COD/m3-d.
C:A recycle line can be added to remove biosolids from the last chamber and return them to the first.
D:Overcome the biosolids loss from the UASB system.
5.Estimating the methane production of anaerobic treatment process for wastewater containing 1.0 M glucose: ( ).
A:2.4 mol.
B:3.36 mol.
C:0.24 mol.
D:2.64 mol.
6.The process of anaerobic treatment can be broken into which of the following steps: ( ).
A:The simple carbohydrates and acids are utilized to obtain energy for growth by fermenting bacteria.
B:Hydrolysis and fermentation of complex organic matter into simple organic acid and hydrogen.
C:The organic acids are then partially used by archael methanogens to convert them into methane.
D:The conversion of the organic acids and hydrogen into methane.
7.An absolute minimum value of θx to allow stable methanogenesis for a CSTR is: ( ).
A:10 day.
B:15 day.
C:5 day.
D:20 day.
8.The contents of the digester can be heated through: ( ).
A:Heat exchangers located inside the digester.
B:Injected steam through lances or diffusers.
C:Pumping back warmed sludge through external heat exchangers
D:Direct heating the reactor.
9.The primary design criterion of CSTR contains: ( ).
A:The net sludge production.
B:The methane-gas yield.
C:Detention time.
D:The volatile-solids loading rate.
10.The routine measurement of volatile acid concentration is of great-importance in the operation and control of anaerobic system.（ ）
A:对 B:错 11.About 15 to 20 percent of the organic matter is converted into biological solids in anaerobic treatment.（ ）
A:对 B:错