Surface water treatment

For turbidity, color and microbiological control in surface water treatment filtration. Common variations of filtration are conventional, direct, slow sand, diatomaceous earth, and membranes. 

EPA s surface water treatment rules require systems using surface water or ground water under the direct influence of surface water to (1) disinfect their water, and (2) filter their water or meet criteria for avoiding filtration so that the following contaminants are controlled at the following levels ... 

Enhanced Surface Water Treatment Rule (ESWTR), 17 804... 

Eliminates the need for surface water treatment may eliminate the need for surface vapor treatment for aerobically biodegradable contaminants in permeable soils. 

A typical scheme for a surface water treatment including preozonation for particle removal is shown below ... 

Figure 3-1 Surface water treatment sequence including particle removal.

Beginning in about 1990, the first microfiltration/ultrafiltration plants were installed to treat municipal surface water supplies [14,15], The driver was implementation of an EPA surface water treatment rule requiring all utilities in the United... 

Croll BT. The installation of GAC and ozone surface water treatment plants in Anglian water, UK. Ozone Sci Eng 1996 18 19-40. 

The EPA Surface Water Treatment Ruse (SWTR) requires public water supplies, under the direct influence of surface water, to be disinfected. Some disinfectants produce chemical by-products SWTR requires that their concentration remain within the MCL. Currently, one such by-product is trihalomethanes. Water disinfection is effective when combined with conventional treatment, such as coagulation, flocculation, sedimentation, and filtration. The latter is accomplished by sand or diatomaceous earth. The effectiveness of disinfection is evaluated by determining total coliform bacteria which are not pathogenic, but their presence suggests that certain pathogens may have survived. The various chemicals commonly used as disinfectants are presented below and some of their advantages and disadvantages are listed. 

Surface water treatment drinking water LP Hg lamps 216 13.824 kW at 253.7 nm UV + chlorination Heterotrophic plate counts Blomberg and Eriksson (2001)... 

Bloomberg J, Eriksson U (2001) From Pilot Plant Studies to a Full-Scale UV Installation at a Large Surface Water Treatment Plant in Sweden, Conference Proceedings of the First International Congress on Ultraviolet Technologies, International Ultraviolet Assoc. (lUVA), June 14—16, Washington, DC, electronic release. 

Letterman, R. D. (1991). Filtration Strategies to Meet the Surface Water Treatment Rule. Am. Water Works Assoc., Denver. 

The advantageous properties of magnesium hydroxide were made use of in another investigation of surface-water treatment where dolomite was applied as coagulant [4 ]. Thus, soft-burned and wet-slaking dolomite appeared to effectively... 

Water treatment in waterworks may be solved by means of either unified or individual technology. In Poland and other countries, the coagulational — adsorptive system, frequently cormected with preliminary oxidation is proposed for surface water treatment. In these solutions, powdered carbon is an adsorptive bed and granular carbon serves to the final purification. In the case of equal concentrations of pollutants only dynamic sorption is used [17—22]. The knowledge of mechanisms of adsorption, sorbent characteristics, concentration and kind of pollutants, other factors influencing sorption capacity of carbons and kinetics of adsorption is required for the correct solution of adsorption processes [23, 24]. 

Diatomaceous earth filter plants have been chosen for projects with limited initial capital, and for emergency or standby capacity to service large seasonal increases in demand. Because these systems are most suitable for applications where influent is low in turbidity and bacterial counts, water supplies presently receiving just chlorination may consider using diatomaceous earth to meet the filtration requirements of the Surface Water Treatment Rules (SWTR) (2). 

In the US EPA publication Small System Compliance Technology List for the Surface Water Treatment Rule (SWTR) and Total Coliform Rule (ICR) (September 1998), DE is a specifically approved filtration technology for compliance with the SWIR. In its comments the US EPA notes that DE is very effective for the removal of Giardia and Cryptosporidium" (23). 

US EPA, Small System Compliance Technology List for the Surface Water Treatment Rule and Total Coliform Rule, US Environmental Protection Agency, Washington, DC, 1998. 

J. C. Kruithof, J. C. Schippers, P. C. Kamp, H. C. Fohner, and J. A. M. H. Hofinan, Integrated multi-objective membrane systems for surface water treatment pretreatment of reverse osmosis by conventional treatment and ultrafiltration. Desalination 117, 37 8 (1998). 

In general, disinfectant dosages will be lessened by placing the point of application towards the end of the water treatment process because of the lower levels of contaminants that would interfere with efficient disinfection. However, water plants with short detention times in clear wells and with nearby first customers may be required to move their point of disinfection upstream to attain the appropriate CT value under the Surface Water Treatment Rule. 

POTABLE WATER CHLORINATION 2,1, Surface Water Treatment Rules... 

On June 29, 1989, the Surface Water Treatment Rules (SWTR) and the Coliform Rule were promulgated. According to the SWTR, all public water systems using surface water or groundwater under direct influence of surface water, must disinfect and may be required to filter if certain source water quality requirements and site-specific conditions are not met. The Maximum Contaminant Level Goals (MCLGs) established in the rule are ... 

Other primary disinfection technologies—chlorine, chlorine dioxide, ozone, UV radiation, and organic disinfectants—are discussed elsewhere (1-3,17-27) in detail. Because most of the utilities that are affected by the Surface Water Treatment Rules and the Ground-Water Disinfection Treatment Rules serve less than 10,000 persons, this chapter wiU emphasize the applications of chlorination and chloramination processes to both small and large utilities. Table 1 indicates that both chlorination and chloramination are comparatively simpler than ozonation UV processes. 

Environmental separation Municipal and industrial waste treatment Ground and surface water treatment Air pollution control VOC removal Mercury vapor removal... 

Ozone is residue-free in water due to its self-decomposition into oxygen. As described above, ozone has been extensively used in water and wastewater treatment since its first full-scale application in drinking water treatment at Oudshoorn, Netherlands, in 1893. To date, ozone has been used full scale for disinfection and purification of ground and surface waters, treatment of municipal and industrial wastewater, and treatment of swimming pool and cooling tower waters.P 4 1 1... 

Currently, high-rate filtration is the most frequently used method for the surface water treatment. As opposed to the slow-rate filtration the layer of a filter bed consists of larger sand grains (diameter 0.5-2 mm) which allows a considerable increase in the rate of filtration. 

Surface water treatment is a controversial issue. A healthy balance between possible risks, such as immediate microbiological contamination and long-term carcinogenic effects due to disinfection byproducts, and the treatment costs is required. Another issue of concern relates to drinking water standards, which seem unreasonably strict in some countries and practically absent in others. The price people are required to pay for their water varies with the standards. 

Pilot studies of surface water treatment using membranes are reported very frequently in the literature. Many full scale applications also exist. With the increase in water quality regulations such installations are expected to become increasingly abundant (Jacangelo et al. (1997)). Levi et al (1997) described a satellite system, where water was treated locally using UF and NF. This avoided contamination by long distribution systems. 

An electronmicrograph of the membrane deposit in the presence of 25 mgL FeCfsand 5 mgL DOC HA is shown in Figure 5.26A, and an electronmicrograph of a deposit of 25 mgL FeCU, 10 mgL hematite and 5 mgL DOC HA in Figure 5.26B. A thick cake is formed on the membrane, and in the presence of hematite this cake is very similar to the cake observed in surface water treatment ( Figure 5.1). 

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