W.C.Water-Winter

1. A collection of minute bubbles formed on the surface of a liquid by agitation, fermentation.
5. A chemical change resulting from biological action.
8. Engineering guidelines that typically specify the amount of influent flow that can be expected on a daily basis over the course of a year.
10. The dynamic response of a system to the addition or deletion of a substance until equilibrium is reached; adjustment to the change in the environment, typically used to describe the response of microorganisms to a change in environment.
14. Limestone that has been 'burned' and treated with water under controlled conditions until the calcium oxide portion has been converted to calcium hydroxide.
16. Pertaining to measurement by volume.
18. A discrete clump of microorganisms on a surface as opposed to dispersed growth throughout a liquid culture medium.
19. The concentration of a test material that causes death of a specified percentage of a population, typically expressed as the median or 50% level.
20. The study of the rates at which changes occur in chemical, physical, and biological treatment processes.

2. A process that produces contact between air and a liquid by spraying, bubbling air through the liquid or agitating the liquid surface.
3. The determination, checking, or rectifying of the graduation of any instrument giving quantitative measurements.
4. The condition of water, wastewater or soil that contains a sufficient amount of alkali substances to raise the pH above 7.0.
6. A substance that resists a change in pH.
7. Materials, generally organic that can be driven off from a sample by heating, typically to 550 deg C.
9. Finely divided solids (smaller than 0.002 mm and larger than 0.000001mm) that will not settle but may be removed by coagulation, biochemical action or membrane filtration; they are intermediate between true solutions and suspensions.
11. The reproducibility of a test or measurement.
12. The application of chlorine compounds to water or wastewater, generally for the purpose of disinfection, but frequently for chemical oxidation and odor control.
13. The liquor in which activated sludge or other matter is kept in suspension.
15. Occurring during the day.
17. Liquid removed by a centrifuge.