ISSN:1061-4303    

DOI:10.2175/WER.64.7.1

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Copper(II) removal efficiency by vermiculite has been investigated through laboratory experiments. The removal phenomenon appears to be consistent with an ion‐exchange (exchange adsorption) process. The batch sorption equilibria follows Freundlich adsorption isotherm. The uptake of copper(II) is a function of the pH of the solution and increases with increasing pH. Increasing ionic strength and the presence of soluble complexing agents such as ethylene diamine tetraacetic acid (EDTA) decrease the sorption of copper (II). The presence of other divalent cations like calcium impede the uptake of copper (II). The presence of chloride ion has no significant effect on copper(II) removal. In a fixed bed vermiculite column, the removal efficiency of copper(II) from tap water is less than that from distilled water. Vermiculite can be regenerated with acid and can then be reused.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.2

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Two nitrification‐denitrification systems were used to determine the possible inhibitory and/or toxic effects of supplementa metals addition to the nitrification‐denitrification process in the treatment of a relatively high ammonia, low biodegradable carbon, municipa landfill leachate.
The addition of metals likely resulted in the precipitation of phosphorus which caused the nitrification‐denitrification process to be inhibited due to the deficiency of bioavailable phosphorus. Even though the phosphorus concentrations in mixed liquor and system effluent samples filtered through Whatman No. 4 filters or glass‐fiber filters appeared to be adequate, it was discovered that they were considerably lower when filtered through 0.45‐µm membrane filters. This seemed to indicate that although some of the precipitated phosphorus passed through the Whatman No. 4 filter, it was not available as a nutrient for microbial metabolism. Therefore, only the phosphorus that will pass through a 0.45‐µm membrane filter, and is defined as soluble in Standard Methods (1985) is readily available to the microorganisms. This should be monitored ensure sufficient nutrient availability in nitrification‐denitrification treatment systems potentially exposed to metals capable of precipitating phosphorus. It is recommended that a minimum soluble phosphorus concentration of 0.5 mg/L be maintained to ensure adequate phosphorus for nitrification and denitrification; in addition, when conducting activated sludge metal toxicity studies, total or Whatman No. 4‐filtered samples should not be used to determine the presence of adequate phosphorus.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.3

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Stream sampling for water quality data has commonly employed simple surface‐grab procedures as opposed to more involved, cross sectionally integrated techniques. Paired samples for analysis of selected constituents were collected over various flow conditions at four sites to evaluate differences between the two sampling methods. Concentrations of dissolved constituents were not consistently different. However, concentrations of suspended sediment and the total forms of some sediment‐associated constituents, such as phosphorus, iron, and manganese, were significantly lower in the surface‐grab samples than in the cross sectionally integrated samples. The largest median percent difference in concentration for a site was 60% (total recoverable manganese). Median percent differences in concentration for sediment‐associated constituents considering all sites grouped were in the range of 20‐25%. The surface‐grab samples underrepresented concentrations of suspended sediment and some sediment‐associated constituents, thus limiting the applicability of such data for certain purposes. An association was also demonstrated between site streamflow characteristics and the observed differences.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.4

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Federal guidelines have been issued that regulate the aqueous discharge concentrations of priority pollutants for the organic chemicals, plastics, and synthetic fibers industries. Insufficient data existed in the literature to allow estimations of the removal of priority pollutants by a wastewater treatment plant (WWTP). The removals of 18 problem organic priority pollutants were measured in five parallel, aerated, continuous, mixed reactors. The influent to the laboratory pilot plants was primary effluent from an industrial 1.75 m3/s (40 Mg/d) WWTP at Du Pont's Chambers Works in Deepwater, N. J. This plant utilizes powdered activated carbon in combination with activated sludge (PACT® Process) in the aeration tanks.
The kinetic coefficients that characterize removal by biodegradation, powdered activated carbon adsorption, and air‐stripping were obtained from the pilot‐plant data, and a steady‐state model was used to predict priority pollutant removals. Good agreement was obtained,”with the exception of three compounds that were batch discharged from the process sources, which invalidated the steady‐state assumption. The model was used to design a second stage PACT unit and to determine source control requirements. The model also can be used to estimate the relative importance of the three removal mechanisms in order to adjust WWTP operating conditions to enhance the removal of specific compounds.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.5

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
In air‐fluidized‐bed bioreactors (AFBBR) for wastewater treatment, reactions were found to take place mainly in the biofilm formed on the surface of the carriers, even when a large number of microorganisms were immobilized in the carriers by an entrapping method. A cylindrically shaped, expanded polypropylene carrier (CEPPC) that is capable of holding a large quantity of microorganisms was developed and tested in continuous experiments. The AFBBR process was proven to be applicable to a high biological oxygen demand (BOD) loading treatment, and the ammonia nitrogen removal rate of the AFBBR process was determined to be higher than that of the fill‐and‐draw type activated sludge process.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.6

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Electrolytic respirometry was used to measure the biodegradability of six phthalate esters (dimethyl phthalate, diethyl phthalate, di‐n‐butyl phthalate, di‐n‐octyl phthalate, butyl benzyl phthalate, and bis [2‐ethylhexyl] phthalate) and four polynuclear aromatic hydrocarbons (naphthalene, phenanthrene, anthracene, and 1,2‐benzanthracene). Mineralization occurred for all compounds except anthracene and 1,2benzanthracene. Determination of all parameters describing biodegradation (μˆ,KS,Y, andb) was possible when a compound was present at a concentration below its solubility limit, but estimates ofKScould not be made with higher concentrations. A modified parameter estimation routine that considered solubility was unsuccessful. Dissolution appeared to govern the degradation rate of compounds present in amounts exceeding their solubility, suggesting that the physical state of such compounds is an important characteristic governing biodegradation.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.7

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
The index of biotic similarity (B) was intended to help pollution biologists reach a better understanding of their data. However, problems that surfaced after its publication in 1976 indicated that improvements would be helpful. This paper presents these improvements. The approach has been threefold: first, we introduce a computer program, BIOSIM l, that automates many of the procedures that would otherwise have to be done laboriously by hand; second, we discuss a thorough and ecologically sound strategy for analyzing data using BIOSIM l; and third, we present ways to use the various options inherent in the first two steps and discuss the ecological conditions under which each option is appropriate.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.8

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
During dredging operation, fine sediment is released in the navigation channel of the Port of Townsville, Australia, as a result of mechanical disturbance of the bed and of the overflow from the storage tanks of the dredger. Some of this sediment is advected away from the dredging site toward the beach and reef areas and could result in environmental damage if not managed properly. Field monitoring was conducted for salinity, temperature, suspended sediment, and acoustic profiles at several sites before and after dredging. Laboratory investigations on the effect of sediment concentration, turbulence, and floe size on the clearing of a suspension column were also undertaken. Results of both field and laboratory investigations show faster clearing in quiescent conditions than in turbulent conditions. Turbulence at low levels disturbs the dewatering microchannels of the fluid mud layer. As turbulence increases the effect of floe breakage and settling retardation also become important.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.9

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
New federal regulations on wastewater sludge management will be implemented in the near future and will have an impact on virtually every biosolids disposal method, including application to agricultural land. Current regulations on land application restrict land use according to the sludge treatment technology, whereas the new regulations will restrict land use based on pathogen destruction criteria. The most flexible land use practices will be allowed for biosolids with low pathogen content (Class A biosolids); for high‐temperature sludge treatment processes (greater than 53°C), indicator organism destruction can be used as a measure of pathogen destruction. The purpose of this study was to evaluate the indicator organism destruction capability of thermophilic anaerobic digestion. For the conditions studied, thermophilic digestion achieved the expected Class A limits on fecal coliforms; data are also presented on fecal streptococci destruction. Rapid startup of the thermophilic reactor (contrasting startup procedures used in the most recent full‐scale studies reported in the literature) and preliminary experiments on stability of the thermophilic population are described as well. Based on the results of this study, it appears that thermophilic anaerobic digestion can be a viable process for achieving Class A biosolids criteria.

ISSN:1061-4303    

DOI:10.2175/WER.64.7.10

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY