Wastewater Treatment Revision crossword

1. The first process in preliminary treatment of wastewater. It involves removing solid debris and grit. (9)
2. The main process in primary treatment of wastewater. The purpose is to remove fine solids. (10)
4. Problematic process that occurs if the tanks are too large, too deep, and Hydraulic Retention Time (HRT) is too great. This issue brings odour problems and rising sludge. (9)
8. For circular settlement tanks, the influent needs to be introduced without resuspending the settling sewage. So a component is added to the tank which reduces the turbulence of the influent. What is that component called? Hint: It is 1-4% of the area. (8, 7)
9. The growth rate of a Micro-Organism can be measured by this empirical equation. (5,8) (5, 8)
10. The unwanted process of groundwater seeping into sewers, thus diluting the sewage and increasing the volume going to treatment plant. (12)

2. Formula for calculating the velocity of settlement. Importantly, it relies on 3 assumptions: discrete particles, spherical shape particles, and laminar flow. (6, 3)
3. Biological Oxygen Demand (BOD) test typically needs 5 days to give a result. It measures biodegradable pollutants in the wastewater. The purpose of the biological treatment process in the treatment plant is to ________ the BOD of the waste water. (8)
6. Trickling filters are a system for pouring wastewater onto stone media, with bacteria living on the stones (in a thin biofilm), to biodegrade the organic pollutants. When the biofilm detaches it is called... (9)
7. Bacteria divide by a process called _______ _______. (6,7) (6, 7)

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