Breakpoint Chlorination Since ammonia is present in all domestic wastewaters, the reaction of ammonia with chlorine is a great significance. When chlorine is added to waters containing ammonia, the ammonia reacts with hypochlorous acid (HOCl) to form monochloramine, dichloramine and trichloramine. The formation of these chloramines depends on the pH of the solution and the…
(Lift Stations) Lift station operation and maintenance costs include power, labor, maintenance, and chemicals (if used for odor control). Usually, the costs for solids disposal are minimal, but are included if the lift station is equipped with bar screens to remove coarse materials from the wastewater. Typically, power costs account for 85 to 95 percent…
Several terms are used to identify the various stages and reactions that occur when chlorine is used as a disinfectant. The basic unit of measurement for chlorination, or any other chemical treatment is milligrams per liter (mg/l) or parts per million (ppm). These are very small units reflecting concentrations that are essentially one part chemical…
(Lift Stations) The most labor-intensive task for lift stations is routine preventive maintenance. A well planned maintenance program for lift station pumps prevents unnecessary equipment wear and downtime. Lift station operators must maintain an inventory of critical spare parts. The number of spare parts in the inventory depends on the critical needs of the unit,…
1. Pipe materials that are the least susceptible to corrosion of acids formed from gases generated in sewers are _. a. ACP b. CIP c. RCP d. VCP 2. A chlorine gas mask should be provided _. a. just outside the chlorine room door b. just inside the chlorine room door c. in the plant…
1. Which of the following practices is not a method for controlling filamentous organisms? a. increase RAS rate b. add hydrogen peroxide at a concentration upwards to 100 ppm to the RAS c. add copper sulfate at a concentration up to 7 ppm to the RAS 2. Trickling filters with synthetic media have a minimum…
1. If 0.75 MGD was treated with a 15% chlorine solution and a dose of 10 ppm was desired, how many gallons of solution would be required per day? 2. How many pounds of BOD were applied to the surface area of a trickling filter if flow = 1.5 MGD and the BOD concentration were…
(Lift Stations) The overall performance of a lift station depends on the performance of the pumps. All pumps have four common performance characteristics: capacity, head, power, and overall efficiency. Capacity (flow rate) is the quantity of liquid pumped per unit of time, typically measured as gallons per minute (gpm) or million gallons per day (MGD)….
Disease-producing microorganisms are potentially present in all wastewaters. These microorganisms must be removed or killed before treated wastewater can be discharged to the receiving waters. The purpose of disinfection is to destroy pathogenic microorganisms and thus prevent the spread of water borne diseases. Although pathogenic microorganisms are reduced in number by the various treatment processes…
Denitrification The control of any biological denitrification process centers around three things: (1) excluding dissolved oxygen, (2) maintaining the proper detention time, and (3) ensuring an adequate carbon source to drive the organisms to denitrify. A D.O. meter is one of the most useful tools for troubleshooting denitrification systems. If any D.O. (>0.1 mg/L) is…
