Manhole Distance / Actual vs On Map A new manhole has been installed 500 ft from an existing manhole. On a map the scale is 1 inch equals 50 ft., what is the distance between the manholes on the map? Given the scale 1 inch equals 50 ft, divide the actual distance by the representative…
To prevent sludge bulking from occurring, the following items should be carefully controlled in an activated sludge plant: 1. Maintain the correct F:M ratio. Carefully review plant records to determine what F:M ratio produces the best quality effluent and long term settling stability. Keep track of influent solids loadings and maintain the desired level of…
Although the activated sludge process can produce an amazingly high quality effluent when it is working well, problems can and do arise. The main problems that occur in the activated sludge process include; solids separation problems, foaming problems, shock loads, septicity and die-off of the microorganisms. Probably one of the most vexing problems encountered by…
Mapping Always keep original maps so that as built plans are available. Update maps whenever new construction or rehabilitation is done in a particular area. Having accurate maps can save time and money when crucial decisions and actions have to be made and executed. The entire collection system should be mapped and all manholes and…
Use the microscope to take a careful look at the spaces between the floc particles. Are there any long, hair-like organisms projecting out of the floc particles? These are filamentous bacteria. Believe it or not, filamentous bacteria of this type are some of the oldest microbes on our planet and have survived unchanged for millions…
A cross connection is connection between a potable (drinking) water system and water from an unsafe or unknown source. A common place in wastewater collection systems where this can occur is on the seal water line for a lift station pump. When potable water is used as the seal water supply and a no protection…
One of the most common formulas used by water and wastewater operators is the pounds formula. This formula is used to determine the loading on the plant and its various process untis; the loading on the receiving water; the amount of chemical needed for a specific function. the formula can also be used to determine…
1. SVI levels are approximately _ for ideal operations. a. 200 mg/L b. 100 mg/L c. 150 mg/L 2. For a conventional activated sludge process, the Food:Microorganism ratio should be in the range of _. a. 2.0 to 5.0 b. 0.01 to 0.07 c. 0.2 to 0.5 d. 0.07 to 0.15 3. What is the…
1. Items that must be examined when inspecting manholes include _. a. corrosion b. cracks c. elevation of lid d. all the above 2. Vibrations in pumps may be caused by improper motor-pump _. a. alignment b. curves c. piping d. power factor 3. Advantages of a video tape recording system include _. a. ability…
For routine microscopic viewing of living mixed liquor, the 10X and 40X lenses will be most useful. Begin by slowly moving back and forth across the slide until the entire contents of the slide has been viewed. This is easily accomplished when using the lower power lenses, which have a wide field of view. Most of…
