ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02898.x

出版商:Wiley    

年代:1987

数据来源: WILEY

摘要:

The increase in water availability fees imposed by a village district so that nonresident landowners could enjoy the privilege of having a water system available to them did not violate the state constitutional provision that requires just compensation, ruled the Supreme Court of New Hampshire.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02902.x

出版商:Wiley    

年代:1987

数据来源: WILEY

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02903.x

出版商:Wiley    

年代:1987

数据来源: WILEY

摘要:

After three years of operation, the showcase Foothills water treatment plant, serving the base needs of the Denver, Colo., metropolitan area, has been performing at, or above, expectations. Taking hydraulic advantage of its location above the city, the plant's pumping costs are minimal and the plant's hydro turbine generates enough power to operate the facilities and sell excess electricity. A minimum staff can operate the automatically controlled processes. The design enables operators to choose the total treatment process or bypass coagulation, flocculation and sedimentation to minimize operation and maintenance costs, depending on seasonal water quality. Solids drying beds take advantage of the climate, further lowering treatment costs, which in 1986 averaged only about $0.03 per thousand gallons.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02904.x

出版商:Wiley    

年代:1987

数据来源: WILEY

摘要:

By 1982, rapid growth in the metropolitan area of Tampa, Fla., had increased the demand for water beyond the capacity of the city's only water treatment plant. Designated an AWWA American Landmark, the Hillsborough River plant had been enlarged three times previously since its construction in 1925. The latest expansion, which was completed last year, added 36 mgd (136,000 m3/d) of capacity without constructing new settling basins. Removal of hydraulic bottlenecks and improvement of flow patterns, rapid‐mixing facilities, and the sludge removal system increased capacity without major new construction, saving about half the estimated cost of new settling basins.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02905.x

出版商:Wiley    

年代:1987

数据来源: WILEY

摘要:

This article is intended to serve as a guide for those who evaluate water treatment plants with the objective of lowering the turbidity of finished water produced from filtration plants in which chemical coagulation is part of the treatment process. Ineffective removal of turbidity may be related to several factors, including the physical condition of the facilities, the hydraulics of treatment processes, the quality of water, and the competence of the operating staff. By preplanning, the evaluation can be conducted in a logical fashion that results in consideration of all necessary and important aspects of the plant and its operation. Descriptions of the proper operation of each component in the process train and pragmatic remedies to improve performance are given.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02906.x

出版商:Wiley    

年代:1987

数据来源: WILEY

摘要:

Options for a gravity filtration unit must be carefully evaluated before an optimum design can be finalized. This article explains a number of alternatives, identifies many of their advantages and disadvantages, and reviews the interrelationship of the components of a filtration system so that alternatives can be matched with the peculiarities of each project under consideration. Examples are provided to demonstrate these concepts.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02907.x

出版商:Wiley    

年代:1987

数据来源: WILEY

摘要:

An investigation of raw and finished waters was conducted (1) to determine whether chlorine dioxide pretreatment lowers trihalomethane (THM) and total organic halide (TOX) formation, (2) to evaluate the rate of chlorine dioxide consumption and the corresponding rate and extent of chlorite formation, and (3) to investigate the stability of chlorite in treated water and its interaction with chlorine. Results of these experiments showed that chlorine dioxide can reduce THM and TOX precursor concentrations and that when added to raw water, chlorine dioxide will not persist long enough to maintain oxidizing conditions through flocculation–sedimentation basins. Utilities should be able to meet the recommended limit of 1.0 mg/L for the sum of the residual chlorine dioxide species by not exceeding a chlorine dioxide dosage of 1.2—1.4 mg/L.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02908.x

出版商:Wiley    

年代:1987

数据来源: WILEY

摘要:

The influence of bromide ion on the formation of nonpurgeable organic bromine and nonpurgeable organic chlorine was not studied previously because no analytical technique existed that could separately measure total organic chlorine and total organic bromine. This measurement has been made possible with the application of the neutron activation analysis. Thus, this study determined the influence of bromide ion concentrations on the relative amounts of nonpurgeable organic chlorine and bromine and chlorine‐substituted and bromine‐substituted trihalomethanes formed during the free chlorination of drinking water over various reaction times and pH values. Measurements of this type are important because bromide ion concentrations are not lowered by conventional drinking water treatment processes, bromide ion is present in many groundwaters, bromide ion may increase the production of trihalomethanes, and the health effects of bromine‐substituted compounds may be different from those of their chlorine‐substituted counterparts.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02909.x

出版商:Wiley    

年代:1987

数据来源: WILEY

摘要:

Iron and manganese problems affect far more water systems than almost any other water quality concern. The committee that prepared this report believes there is still much to learn about the chemistry, treatment, and control of iron and manganese and that there is considerable room to improve treatment effectiveness while reducing treatment costs. Such goals are especially relevant to small water systems, which are frequently afflicted with iron and manganese problems.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1987.tb02910.x

出版商:Wiley    

年代:1987

数据来源: WILEY