Potable water supply

Potable Water Supply The scaling problem in potable water supply lines is due mainly to calcium cerbonate deposit accumulation on the pipe surface when the flowing water is supersaturated. Two situations are of prectical interest  

The main targets of investment are likely to be renewal and improvement of supply in developed cities, and the provision of low cost clean water in undeveloped countries. The former is characterised by decay of existing infrastructures, typically 50 to 100 years old, with associated large leakage rates and inefficiency of supply. The problems of 

Tab e 3.3 West European Potable Water Usage (Per Year)  

Country Domestic Total (10 m /y) Domestic per Person (m /y) Domestic per Dwelling (m%) Industrial Totals (bm ) 

Principle Source EU Panorama 95 (Review Water Supply and Distribution, written by EUREAN)  

The high level of interest in reducing lead concentrations also raised some questions about the leaching of lead-based stabiliser compounds from PVC pipe. A number of European pipe manufacturers have already moved to non-lead stabiliser systems and it is likely that such moves will be completed by voluntary action before legislation is introduced [40]. 

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Abundant supplies of fresh water are essential to the development of industry. Enormous quantities are required for the cooling of products and equipment, for process needs, for boiler feed, and for sanitary and potable water supply. 

Amenity, e.g. loss of recreation facilities Loss of potable water supplies (rivers, reservoirs, aquifers)... 

The problem has been recognized by many of the developers concerned, who have consequently themselves adopted the environmental standards of other industrialized nations. In the absence of national controls this is a responsible and laudable approach. However, the piecemeal adoption of standards taken from elsewhere does not take account of local conditions. These conditions may either enhance or limit the ability of the environment to disperse and attenuate or assimilate pollutants (e.g. the occurrence of temperature inversions will limit the dispersion of air pollutants). Similarly, the use to which local resources are put may demand particularly high standards of environmental quality (e.g. the use of sea water or river water as the basis of potable water supply). The choice of standards must also take into account local practices and existing local administration. 

Obrecht, M. F., Sastor, W. E. and Keyes, J. M., Integrated Design of Field Test Panel Pilot Unit for Investigating Pitting Corrosion of Copper Water Tube by Potable Water Supplies , Proc. 4th Int. Congr. Met. Corr., 1969, 576 (1972)... 

Burman N.P. Colboume J.S. (1977) Techniques for the assessment of growth of microorganisms on plumbing materials used in contact with potable water supplies. JAppl Bacterial, 43, 137— 144. 

The Department of Ecology strongly recommended against Superfund status on the grounds that the EPA site evaluation included a population impact based on the number of people who could have been affected in a three-mile radius instead of the population actually affected taking into consideration the directions of ground water movement. Providing the affected residences with a potable water supply by the Company and the impacts of total vs. free cyanide were discussed by EPA but were not used in the impact analysis. 

The use of chlorine dioxide in water systems results in its reduction to chlorite and chloride. In the UK the Drinking Water Inspectorate (DWI) restricts the use of chlorine dioxide in potable water supplies to a maximum of 0.5ppm total oxidants expressed as chlorine dioxide. This ensures that chlorite (and any chlorate) concentrations do not reach levels of potential harm to humans. 

Protected for wildlife, fish, aquatic and semiaquatic life and secondary contact water uses h Protected as a raw water source of potable water supply... 

Hess et al. (1987) show that for areas where there is high radon in the potable water supply, water can represent a significant source of indoor radon. However, there are ways of removing radon from water including aeration or carbon adsorption. 

Laboratory rooms intended for toxic work should be provided with adjacent shower and change facilities. The layout must not require freshly showered personnel to track back through the area that they might have just contaminated. All drains, including those in laboratory floors, should have deep traps and be directed to a toxic sump. Airlocks will help prevent toxic fumes from spreading to non-toxic areas in the event of a failure of a primary containment cabinet. Check valves in the incoming water lines will prevent contamination of potable water supplies when pressure is lost. 

ISO 2898-1 1996 Plastics - Plasticized poly(vinyl chloride) (PVC-P) moulding and extrusion materials - Part 1 Designation system and basis for specifications ISO 2898-2 1997 Plastics - Plasticized poly(vinyl chloride) (PVC-P) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 3114 1977 Unplasticized polyvinyl chloride (PVC) pipes for potable water supply -Extractability of lead and tin - Test method... 

Israel is already exploiting all of its limited drinking water sources and reduction of the amount of potable water supplied to agriculture is being seriously considered. 

Moore GS, Calabrese EJ, DiNardi SR, et al. 1978. Potential health effects of chlorine dioxide as a disinfectant in potable water supplies. Med Hypotheses 4(5) 481-496. 

ShallowTray air strippers are low-profile, transportable units for removal of volatile contaminants from aqueous waste streams and potable water supplies. Air strippers do not destroy contaminants but transfer them to the airstream, where they can be destroyed by incineration or oxidation, removed by activated carbon, or released into the atmosphere if relevant emissions criteria are met. 

Svec HJ, Fritz JS, Calder GV. 1974. Trace soluble organic compounds in potable water supplies. Report to U.S. Department of Interior, Office of Water Resources Research, by Iowa State University, Department of Chemistry, Ames, lA. NTIS No. PB-228523. 

POLYMERIC SORBENTS are frequently used in environmental analytical schemes for the isolation and/or preconcentration of trace organic contaminants from air and water matrices. Commercially manufactured polymeric sorbents such as Amberlite XAD resins, Ambersorb XE resins, Tenax (diphenyl-p-phenylene oxide), and polyurethane foam (PUF) have been used extensively for the collection of trace organic contaminants from ambient air, process streams (i.e., flue gas), and a variety of aquatic matrices including industrial effluents, ground water, surface water, and potable water supplies. Currently, these materials... 

Nitrate is of interest as a possible indication of watering. Many potable water supplies contain 30 mg/liter of nitrate whereas normal wines contain about 4-5 mg/liter on the average (46,47,48). The present recommended procedure (49) is reduction of nitrate to nitrite followed by colorimetric determination with sulfanilic acid and a-naphthylamine. 

Typically, we will undertake serious action if the level of live planktonic organisms found in a cooling system reaches between 1 x 105 and 1 x 106 aerobic colony-forming units per milliliter (CFU/ml). When we compare this with a potable water supply that may contain only 20 to 200 CFU/ml, it appears to be a large number however, on a weight basis, this still represents an incredibly small amount of contamination, probably much less than the daily contaminant load from air-blown dust and soil. 

Application of RO for water production is now a well-accepted and economical process even for higher concentration seawater with osmotic pressures of over 300 psi. Malta, for example, has evolved an economical reliable application of this technology to produce 60% of its potable water supply (Lamendolar and Tua, 1995). 

US Environmental Protection Agency (USEPA), Technologies and costs for the removal of fluoride from potable water supplies, Science and Technology Branch Criteria and Standards Division, Office of Drinking water, Washington, DC, 1985, 29-32. 

Neither of the nitrophenols was detected in water from Lake Erie and Lake Michigan (Great Lakes Water Quality Board 1983). Based on data from EPA s STORET database since 1980 (to assure better data quality), neither of the nitrophenols was detected in any of the over 800 ambient surface water samples analyzed (Staples et al. 1985). 4-Nitrophenol at a concentration of 0.2 mg/L was detected in the potable water supply of Ames, Iowa. The source of the compound was speculated to be the contamination of well water from the wastes of a coal gas plant after the plant ceased operation around 1930 (EPA 1980). No other detection of either nitrophenol in US. drinking waters was reported. 

The presence of oestrogenic compounds in potable water supplies has also raised concerns in recent years. The destruction of 17-/i-oeslradiaol on immobilised TiC>2 films has been achieved with 98% decomposition observed in 3.5 h photocatalysis [169]. 

Stormwater/urban runoff is discharged to ground close to a well used for potable water supply. Stormwater is discharged ... 

In the USA, where similar studies have been carried out in treated waters and streams,Stackelberg and co-workers have demonstrated that many of the PPCPs can survive conventional drinking-water-treatment and occur in potable water supplies. Although concentrations in finished water were low (93%<0.5pg L ) and the maximum possible lifetime intake of, for example, carbamazepine would be only 13 mg, compared with a single therapeutic dose of 100 mg, little is known about potential health effects associated with chronic ingestion via drinking water. 

McClean JC (2001) Ultraviolet Photolysis of Pesticides in Potable Water Supplies 5 Years Operating Experience, Conference Proceedings of the First International Congress on Ultraviolet Technologies, I nterna-tional Ultraviolet Assoc. (lUVA), June 14— 16, Washington, DC, electronic release. 

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