ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07343.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Regulations will ultimately require nearly all surface water supplies to be filtered. Together, the water supply professionals, the regulators, and the small communities need to take a closer look at cost‐efficient, low‐surveillance technologies that provide safe, reliable water. Slow sand filtration, one such technology, is experiencing a renaissance of attention. It is an energy‐efficient, lowcost, basic technology that can achieve substantial savings through efficiency of design and simplicity of operation while providing safe water to consumers. However, there is a dark side–inappropriate regulatory requirements and antiquated design criteria.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07344.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

In 1987, William Morris filed an application to appropriate groundwater for a proposed residential subdivision in Lovell Canyon, Nevada. The state engineer found that the point at which the proposed water appropriation was to be made (the point of diversion) was within the Pahrump Valley Groundwater Basin. He further concluded that the groundwater basin was overappropriated, and he denied the application. Morris appealed to the trial court and won a reversal.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07348.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

The increasing number of drinking water regulations being set by the USEPA and limited financial resources are creating a dilemma for many small water systems. Achieving compliance with the regulations within the time frames specified by the USEPA may not be possible, particularly for small systems. Under certain circumstances, the Safe Drinking Water Act (SDWA) allows water utilities to seek additional time to comply with new regulations by obtaining a variance or an exemption. Variance and exemption criteria are given.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07349.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

The nine participants of this discussion provide an overview of small systems. Issues concerning compliance and support, enforcement and technical assistance, small systems' training needs, alternative or low‐cost technology, regionalization, and contract operations and management are broadly discussed.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07350.x

出版商:Wiley    

年代:1992

数据来源: WILEY

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07351.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Owners and customers of small water systems are at a crossroads. They will soon face the need to make significant investments and bear much greater operating costs to comply with increasingly stringent performance requirements under the Safe Drinking Water Act. Meeting thest demands will expose additional needs to replace deteriorate infrastructurs. A piecemeal approach to coping with the new environment could become a trap if the full scope of these liabilities is not appreciated at the outset. By taking a comprehensive view, systems can either find the assurance they need to move forward confidently on their own or discover restructuring opportunities involving alternative structural or institutional arrangements. This article describes the strategy adopted by Pennsylvania to improve visibility and thereby enhance the viability of small systems.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07352.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Bringing small water systems into compliance with the ever‐increasing number of regulations will require flexibility in terms of technology application and institutional procedures. This article looks at the means by which small systems can provide safe drinking water, focusing on the advantages, disadvantages, and costs of several treatment options—full‐scale conventional treatment, centrally located package plants, and point‐of‐use or point‐of‐entry devices—for various scenarios.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07353.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

A subdivision in the foothills of Colorado's Rocky Mountains has built a small system whose water meets or exceeds state and federal guidelines. Eighty‐four homes are connected to the system, which can potentialiy accommodate 125 homes. The unique geologic setting introduced water quality problems such as radioactive contaminants as well as more conventional iron and corrosion problems. Communitywide support and involvement assured the success of the project, which was accomplished without outside subsidies. Community residents with expertise in geology, engineering, construction, and financial and business management volunteered their help to design, build, and maintain the system. This donated expertise is estimated to have saved the water district $300,000 to date. In addition to local expertise and voluntecrism, the author considers other issues of importance to small systems: responsible interest in health effects, planning on a small system level, and contract management guided by engineering expertise.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07354.x

出版商:Wiley    

年代:1992

数据来源: WILEY

摘要:

Inclined cascade aeration (ICA) was effective in removing 10 chlorinated volatile organic chemicals (VOCs) from drinking water at liquid loadings of 5 gpm/ft (1.04 L s–1/m) to 15 gpm/ft (3.1 L s–1/m). Overall mass transfer (or desorption) coefficients (KLav) were an order of magnitude larger (0.08–0.54 s–1) than those reported for packed‐tower aeration. A curve fit of the experimental data for all 10 VOCs with the equation KLav= 0.019 + 0.091 (Hp)$f14(sin θ)$, in which Hp is the Henry's law constant (atm) and θ is the angle of inclination, yielded desorption coefficients within ± 18 percent of experimental values. A cascade angle of 60° was found most efftcacious for compounds with Hp values>300 atm; compounds with Hp values<300 atm were most effectively stripped at yet steeper angles.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1992.tb07355.x

出版商:Wiley    

年代:1992

数据来源: WILEY