Problems water treatment plants

Disposal of the solutions of aluminum salts generated in the Eriedel-Crafts process presents an environmental problem unless use can be found for them as coagulants in a water treatment plant. 

Water-treatment plant may include one or more electric motors driving feedwater pumps or dosing pumps. Dosing pumps are usually very small and will not cause noise problems. Water pumps may be considered as for the feedwater pumps already described. 

The volume of wastewater produced from a potable water treatment plant (either a conventional sedimentation filtration plant or an innovative flotation filtration plant) amounts to about 15% of a plant s total flow. Total wastewater recycle for production of potable water may save water and cost, and solve wastewater discharge problems [15,35-38]. 

The magnitude of error that can be caused by neglecting these problems depends on the system used. Most of theses problems are not serious in the case of small kLa v, e. g. for the range normally found in waste water treatment plants (0.001-0.005 s-1). For example, Brown... 

Microfilters are used in the electronics industry, principally as final point-of-use filters for ultrapure water. The water is already very pure and almost completely particle- and salt-free, so the only potential problem is contamination in the piping from the central water treatment plant to the device fabrication area. Although fine filters with 0.1 pm pore diameter or less may be used, lifetimes are relatively long. 

In recent years, environmental concerns over water quality have led to installation of waste water treatment plants at pulp and paper mills. The underflow from the primary clarifier has generated another solid waste disposal problem. To solve this problem, some mills are feeding clarifier sludge to hog fuel boilers. The high moisture content of the sludge in conjunction with its low Btu content creates more difficult operating conditions for the furnace. Comparative composition of TDF, coal, wood waste,... 

Based on some experimental results, application of the UV/H202 system to eliminate the bromate problem appears to be worthwhile. For example, Kruithof et al. [197], while studying the optimum conditions for disinfection and pesticide removal in a drinking water treatment plant, found that in the range 0.1-2.5 kWh m-3 electric energy (with medium-pressure UV lamps) and 0-25 gm-3 H202, bromate formation was absent. The main drawback was increased assimilable organic carbon, which would necessitate the use of activated carbon filters. 

Occasionally, drinking water treatment plants will have taste and odor problems that result in a lot of complaints from their customers (after all, who wants smelly drinking water ). One compound that causes this problem is called geosmin.2 Assuming this compound has a chemical degradation rate constant of 6.6 x 10-3 s 1, at what flow rate could a treatment plant with a volume of 2500 m3 be operated if a 10-min water contact time is required to remove qeosmin ... 

A water treatment plant drawing water at rate of 8 mVs from a shoreline intake is protected by bar screen. The head loss across the screen is 0.17 m. The bar width is 20 mm and the bar spacing is 70 mm. Assuming that the screen is 30% clogged and using the clear space opening in Problem 5.2, calculate the value of C. ... 

This pilot-scale has confirmed our earlier observations from full-scale drinking-water treatment plants. Such a detailed and systematic analysis of the amino acid concentrations allow one to monitor the degree of colonization of the filter media. Such colonization presents a problem when it is not wanted or improperly controlled. In these cases, it may be possible to disinfect and then wash the filtey media to decrease the release of amino acids. 

The experimental procedures to establish water treatment plant operational practices have not been without problems. A few of these problems were engineering in nature, such as material compatibility, type of pumps, chemical phase (liquid or solid). Feeding fluoride is like feeding other chemicals experience provides insight in determining the best type of equipment. The feed equipment is in general the same equipment used for feeding alum, soda ash, lime, sulfuric acid, or other chemicals. 

A water treatment plant is using silicofluoride for fluoridation. To prevent feeding problems, the operational staff requested all shipment be subject to the feedability index prior to shipment. 

The feedability value indicated that this material would be troublesome, with the excess ultra-fine powder (the portion passing through the 325-mesh sieve) causing arching, flooding, and dust problems. Therefore, Batch 1 was ordered and shipped to the water treatment plant. 

Selenium enters the refinery as contaminates of processed crude oils. As the refiner processes the cmde oil, the selenium contaminate migrates fi om the crude oil into the refinery s striped sour water (SSW) streams. Once in the SSW stream, the selenium contaminate, which is an environmental concern, is now part of the wastewater stream. The problem for the refiner is how to efficiently remove the selenium prior to discharging the water to an appropriate catch, such as a bay or municipal water treatment plant. 

---