ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03312.x

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

A federal appellate court held that an industrial user of a publicly owned treatment works (POTW) could be liable under the Clean Water Act (CWA) even if the user's discharge was not a significant contribution to the POTW's violation of its permit.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03316.x

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

This roundtable discussion focuses on the enforcement of Safe Drinking Water Act (SDWA) regulations. Reflecting its dissatisfaction with the US Environmental Protection Agency's track record of enforcing the SDWA, Congress gave the agency new enforcement powers and the mandate to use them when it passed the 1986 SDWA amendments. The change in enforcement status quo has raised numerous questions among those responsible for achieving and ensuring compliance, especially in light of the promise of a dramatically increased number of regulations.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03317.x

出版商:Wiley    

年代:1989

数据来源: WILEY

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03318.x

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Water supply pumps can account for a great deal of the energy consumed by municipalities. Significant reductions in energy consumption and costs can be obtained by identifying and using the most efficient pump combination for a given situation. A procedure for identifying such a combination is presented in this article.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03319.x

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Operators of several drinking water systems that are vulnerable to contamination by synthetic and volatile organic chemicals have shown interest in modifying existing treatment plants to include granular activated carbon (GAC) adsorption. An important consideration in the evaluation of GAC treatment alternatives is the examination of cost factors. This article presents preliminary cost estimates for various applications over a range of system sizes and carbon bed lives. Costs related to postfilter adsorbers using steel pressure and concrete gravity contactors are examined, as well as costs associated with fluid‐bed, infrared, and multihearth reactivation technologies.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03320.x

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Numerous pesticides were monitored in surface waters in agricultural areas. Atrazine, alachlor, metolachlor, cyanazine, metribuzin, carbofuran, linuron, and simazine were found in the influent to three water treatment plants in stormwater runoff. Studies at these plants, together with bench‐scale studies, demonstrated poor control by conventional treatment processes. The relatively high adsorption capacities of these agrichemicals indicate that granular activated carbon can be cost effective for their control. Powdered activated carbon applied at dosages used for the control of tastes and odors can also be effective if moderate percent removal is required.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03321.x

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Adsorption of natural organic matter on activated alumina (AA) improved when the organic matter was preoxidized with either ozone or hydrogen peroxide. The alumina was effectively regenerated in the laboratory with 0.1 percent (or greater) NaOH solutions, i.e., more than 8 × 10−4mol NaOH/g AA. The spent regenerant could be reused several times to reduce the quantity of process waste. The use of AA before granular activated carbon (GAC), combined with in situ regeneration of the AA, resulted in an 80 percent higher capacity of GAC for an organic micropollutant—2,4,‐dichlorophenol. Presumably there was reduced competition for adsorption sites on the GAC because the dichlorophenol was not adsorbed by the AA Pilot tests of AA adsorbers in parallel with GAC adsorbers showed that GAC had a higher capacity and could adsorb a larger percentage of natural organics than AA, that AA did not adsorb the semivolatile organics (analyzable by gas chromatography‐mass spectroscopy) in a surface water, and that preozonation improved removal by AA and GAC.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03322.x

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

Acid‐base reactions occur simultaneously with gas transfer reactions in several common applications in water and wastewater treatment. A simple methodology to account quantitatively for the effects of the acid‐base reactions on the gas transfer rate was developed, checked by comparison with laboratory data, and applied to an actual drinking water problem situation. Equations for application to a variety of gas‐liquid contacting reactors are given. The rate of gas adsorption or stripping was shown to be drastically influenced by pH in applicable cases. Laboratory results for stripping of carbon dioxide in batch reactors and continuous‐flow countercurrent packed towers compared excellently with the theory. The theory was applied to a full‐scale operating system in which hydrogen sulfide is stripped from a groundwater drinking water supply; simultaneous stripping of carbon dioxide and oxidation of the sulfide were accounted for. Reduction of the influent pH was recommended to improve the stripping of the hydrogen sulfide.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03323.x

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

A liquid‐phase granular activated carbon (GAC) pilot plant and a full‐scale GAC adsorber were designed, built, and operated in order to evaluate their performance for treating a groundwater contaminated with several volatile and synthetic organic chemicals. Several empty bed contact times (EBCTs) ranging from 1 to 30 min were used during the pilot‐plant study, and a simple method for evaluating the GAC use rate as a function of EBCT was developed and demonstrated for dichloroethene and trichloroethene (TCE). Pilot‐plant data were compared with the pore surface diffusion model, which considers external and internal mass transfer mechanisms of pore and surface diffusion. Natural organic matter in the water was found to decrease GAC capacity and kinetics for TCE.

ISSN:0003-150X    

DOI:10.1002/j.1551-8833.1989.tb03324.x

出版商:Wiley    

年代:1989

数据来源: WILEY