(Lift Stations) Ventilation Ventilation and heating are required if the lift station includes an area routinely entered by personnel. Ventilation is particularly important to prevent the collection of toxic and/or explosive gases. According to the Nation Fire Protection Association (NFPA) Section 820, all continuous ventilation systems should be fitted with flow detection devices connected to…
(Lift Stations) Wet Well Wet-well design depends on the type of lift station configuration (submersible or drywell) and the type of pump controls (constant or variable speed). Wet-wells are typically designed large enough to prevent rapid pump cycling but small enough to prevent a long detention time and associated odor release. Wet-well maximum detention time…
Denitrification The microorganisms involved in denitrification are much more varied and plentiful than those involved in nitrification. They are also much less sensitive to environmental changes than the nitrifiers. Systems that nitrify and denitrify have the advantage of regaining about 50% of the alkalinity lost during nitrification, because alkalinity is created as part of the…
Suspended Growth Processes (Nitrification) Activated sludge processes can be operated in a variety of modes. Not all modes of operation are conducive to nitrification. Conventional activated sludge lends itself well to nitrification because the plug flow through the basin allows for the assimilation of BOD by the Heterotrophs prior to the start of nitrification. Adequate…
(Lift Stations) Calculating Velocity Wastewater is pumped into a 6 inch line by a 300 gal/min pump that is 85 % efficient, what is the velocity of the wastewater in the line? The velocity can be found by using the velocity equation V = Q/A. the flow (Q) is given and solving for the area…
Dry Pit A key advantage of dry-well lift stations is that they allow easy access for routine visual inspection and maintenance. In general, they are easier to repair than submersible pumps. An advantage of submersible lift stations is that they typically cost less than dry-well stations and operate without frequent pump maintenance. Submersible lift stations…
Operational Control of Nitrification and Denitrification The two part process of biological nitrogen removal through nitrification/denitrification requires that ammonia if first converted into nitrite and then nitrate, and then that the nitrate be converted into nitrogen gas, which is released to the atmosphere. The nitrification portion of biological nitrogen removal can be accomplished using either…
1. How many million gallons are in a storage tank if 20 lbs of chlorine produced a dose of 4 ppm? 2. If a tank measured 40 ft in diameter and 30 ft tall, how many pounds of chlorine is needed to dose it at 9 mg/L? 3. A water pipe is 2 miles long…
1. Which of the following is not one of the four important physical variables that control the performance of a wet air oxidation unit? a. temperature b. air supply c. type of sludge d. feed solids concentration e. pressure 2. Which of the following is not an advantage of using heat treatment on sludge? a….
1. Results obtained from pipe roughness coefficient tests can indicate whether or not _. a. contamination is entering the pipe b. the ability of the pipe to transmit flow is being hindered c. the quality of the wastewater in the pipe is deteriorating d. the size and number of leaks are increasing 2. Anaerobic wastewater…
