| # | What is incineration? | Conversion of organics into gas during anaerobic digestion. | The conversion of dewatered sludge to ash, H2O, & CO2 by burning. | A mechanical device used to burn sludge. | A phosphorus removal technique to reclaim lime. | none of the above | 2
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| 1 | Which gas is produced in anaerobic digesters and can be used as a fuel? | propane. | methane. | ethane. | carbon dioxide. | none of the above. | 2 |
| 2 | What is the purpose of heating and mixing a primary anaerobic digester? | to eliminate all oxygen present. | to increase the digestion rate. | to keep methane gas in suspension. | to prevent settling of grit to the bottom of the digester. | none of the above. | 2 |
| 3 | The method of sludge handling resulting in a supernatant with the highest BOD is | aerobic digestion. | anaerobic digestion. | centrifugation. | vacuum filtration. | none of the above. | 3 |
| 4 | Which solids can not be removed by vacuum filtration? | dissolved solids. | settleable solids. | suspended solids. | total solids. | none of the above. | 1 |
| 5 | Belt filter press are operated as a _______ process. | batch. | continuous. | either one, depending on the circumstances. | all of the above. | none of the above. | 2 |
| 6 | What will not affect the vacuum produced in a vacuum filter system? | clogged silencer drain. | drum speed. | poor filtrate pump performance. | seal water flow to the vacuum pump. | none of the above. | 2
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