ISSN:1061-4303    

DOI:10.2175/WER.64.5.1

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Validation work was carried out to develop analytical protocols for fatty and resin acids in water, sediment, and fish bile samples in the µg/L, tenths of µg/g, and µg/g, range respectively. The methods, with similar steps for the different media, involved extraction from a pH 5 medium witht‐butyl methyl ether/dichloromethane solutions, with previous enzymatic hydrolysis in the case of bile samples. Concentration of the extract and derivatization with diazomethane in organic solution yielded the methyl esters, which were analyzed by GC‐SIM‐MS. Good recoveries (60–110%) and excellent precision (SD = 2–11%) were obtained for the twelve target compounds. Application of these methods to samples from the northern Alberta region yielded satisfactory results (surrogate recoveries = 75–110%).

ISSN:1061-4303    

DOI:10.2175/WER.64.5.2

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
The need for multimedia environmental studies on pulp mill effluent contaminants was addressed by refining and validating analytical protocols for the analysis of chlorinated phenols, guaiacols, catechols, phenolic aldehydes, and polymethoxybenzenes in water (µg/L range), sediment, and fish tissue samples (tenths of µ/g range). The methods, with common features for the different media, involved extraction witht‐butyl methyl ether/dichloromethane solutions, with ascorbic acid added as an antioxidant. In the case of fish tissue, sample cleanup by size exclusion chromatography was carried out to reduce lipid interference. Derivatization with acetic anhydride /pyridine in organic solution yielded the acetates, which were analyzed by GC‐SIM‐MS. Excellent precision (SD = 2–15%) and satisfactory recoveries (42–115%) were achieved for most of the 32 contaminants evaluated. Application of these methods to samples from the northern Alberta region yielded satisfactory results (surrogate recoveries = 94–134%).

ISSN:1061-4303    

DOI:10.2175/WER.64.5.3

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Biodegradation studies of 1 mM aqueous pentachlorophenol (PCP) solutions have been conducted in completely mixed batch reactors using a selected microbial consortium (SMC) and a stock culture of activated sludge (AS). Comparable biodegradation has also been carried out following chemical oxidation pretreatment by hydrogen peroxide alone and by Fenton's reagent (a solution of hydrogen peroxide with ferrous ion) in order to observe any enhancement of biodegradation.
The microbial species isolated from the soil contaminated by PCP were gram‐negative, rod‐shaped bacteria, identified asPseudomonas putidaandPseudomonas aeruginosa. The stock culture of activated sludge was developed from a wastewater treatment plant treating domestic wastewater only and maintained on tryptic soy broth substrate.
Chemical oxidation pretreatment experiments were conducted in the absence of SMC and AS, and the chemical oxidation reaction was almost complete after four hours of reaction. The highest PCP removal by chemical oxidation tested in this study was 2.97% with Fenton's reagent at a molar ratio of 1:1 (H202:PCP) and 50 mg/L iron.
The biodegradation process was carried out on both pretreated and untreated PCP for 12 days, but the biodegradation was almost complete by the sixth day. Inoculation of SMC or AS into the aqueous PCP solutions following pretreatment by Fenton's reagent resulted in a higher PCP uptake rate than did the system treated by hydrogen peroxide alone. The enhanced biodegradation rate was highest when the system was pretreated by Fenton's reagent with the highest chemical oxidant dose, a 1:1 molar ratio of hydrogen peroxide to PCP and 50 mg/L iron. The biodegradation rates of untreated PCP, degraded by either SMC or AS, were each similar and much slower than for any of the pretreated systems.
Comparison of the biodegradation rate of the un‐pretreated PCP with the rates of pretreated systems indicated that chemical oxidation by Fenton's reagent enhanced the biodegradability of PCP by both SMC and AS.

ISSN:1061-4303    

DOI:10.2175/WER.64.5.4

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Because the aeration system in an activated sludge wastewater treatment plant typically represents more than 50% of total plant energy requirements, designers and operators can substantially reduce overall plant energy costs by using accurate oxygen transfer information to make the aeration system as energy efficient as possible.
This paper presents data from 65 off‐gas analysis tests performed at 21 wastewater treatment plants. The effect of various factors on oxygen transfer was evaluated by comparing pairs of tests in which all factors but one were held relatively constant. Factors evaluated were diffuser type, diffuser layout, diffuser age, solids retention time, and level of nitrification. Flexible membrane diffusers had more than a 30% higher oxygen transfer efficiency than coarse bubble diffusers. Grid layouts had higher oxygen transfer efficiencies than spiral roll layouts. Flexible membrane diffusers that were 3.5 years old had a 20% lower oxygen transfer efficiency than new flexible membrane diffusers. Systems at low solids retention times that were not nitrifying had lower oxygen transfer efficiencies than nitrifying systems at high solids retention times. For some wastewater systems, use of this information on solids retention time in plant design and operation can decrease overall energy costs despite the additional oxygen required to meet the nitrogenous oxygen demand.

ISSN:1061-4303    

DOI:10.2175/WER.64.5.5

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Efficient removal of nutrients from municipal sewage treatment plant wastewater is needed to protect surface waters from eutrophication, but artificial peat beds designed for this purpose have proved unsuccessful for phosphorus removal. Laboratory studies were conducted to evaluate the feasibility of adding iron oxides or steel wool to peat and sand to increase phosphate sorption. Langmuir‐type batch isotherms and column leaching studies showed that preformed rust and untreated steel wool markedly increased phosphorus sorption by peat and sand, with the steel wool‐peat combination removing the most phosphorus under realistic, leaching conditions. Estimated useful lives for the ironamended materials ranged from zero years for unamended sand to several years for steel wool‐amended peat, depending on quantities of iron material added. The results suggested that steel wool offers a low‐cost, efficient amendment for peat and sand beds designed for phosphorus removal from wastewater.

ISSN:1061-4303    

DOI:10.2175/WER.64.5.6

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
The goal of the research was to evaluate whether the method of normalized loading curves could explain the performance differences among three steady‐state biofilm processes that had nearly identical loadings and process configurations. Three methanogenic fluidized‐bed biofilm reactors were challenged with a range of surface loadings of three distinctly different organic substrates: acetate, phenol, and glucose. Normalized loading curves were generated from the four fundamental parameters (Smin,S*min,K* ,JR) and compared to the experimental performance. The curves and the fundamental parameters explained why effluent concentrations of acetate and phenol were sensitive to loading, while the glucose concentration was insensitive; why effluent concentrations were much lower for phenol than for glucose at similar surface loads; and why acetate required a much higher surface loading to give similar performance trends.

ISSN:1061-4303    

DOI:10.2175/WER.64.5.7

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Laboratory experiments were conducted with a sequencing, packed‐bed bioreactor that was seeded with the methanotroph,Methylosinus trichosporiumOB3b. The reactor cycled between a growth mode, in which methane and oxygen were supplied from the gas phase, and a degradation mode, in which water containing chloroform at 100 µg/L was treated in the absence of methane. When the influent was supplemented with formate, chloroform degradation was as great as 90% at an empty bed retention time of approximately 90 minutes. The degradation rate remained stable for several days, but steadily declined thereafter. In the absence of formate, the initial degradation rate was smaller and declined more rapidly than in the presence of formate. Mathematical modeling demonstrated that the pseudo‐first‐order rate constants for chloroform degradation in the reactor were about two orders of magnitude smaller than those measured in suspended growth, batch kinetic studies. The sequencing reactor performed better than a packedbed, continuous‐flow reactor, because a larger, more evenly distributed biomass could be established in the sequencing reactor.

ISSN:1061-4303    

DOI:10.2175/WER.64.5.8

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
Odors associated with wastewater collection and treatment are a common problem. Wastewater odors are difficult to quantify, and current methods of quantification are too cumbersome to permit long‐term evaluation of odor problems. In this project, residents in affected neighborhoods near a treatment plant in Winston‐Salem, North Carolina quantified odors by completing numerical odor rating forms three times a day for six months. The resulting database was used to evaluate the correlation of odors to a variety of factors. Residents from the same neighborhood had a high level of agreement in quantifying odors, and most participants had a reasonable ability to make distinctions among different degrees of odor. Odors correlated well with wastewater characteristics (for example, influent COD) and wind direction, implicating the treatment plant as the major source of odors in affected neighborhoods. Use of the numerical odor rating form was an effective and inexpensive means of quantifying wastewater odors, and in conjunction with other information gave a better picture of specific major sources of odor at the treatment plant.

ISSN:1061-4303    

DOI:10.2175/WER.64.5.9

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY

摘要:

ABSTRACT:
The effects of particulate and soluble organic matter (BOD) on nitrification were investigated in laboratory experiments using a bench‐scale rotating biological contactor (RBC). This work was initiated by lower than expected nitrification rates in the second stage biofilm processes at the Longmont Waste Water Treatment Plant (LWWTP). It was hypothesized that this was due to particulate matter since soluble BOD in the influent was low.
For a range of 12 and 82 mg/L total BOD to the pilot RBC; particulate BOD was found to inhibit nitrification to the same degree as soluble BOD. In fact, total (soluble plus particulate) influent organic matter was found to be a better predictor of nitrification than soluble organic matter concentration. The inhibition of nitrification by particulate BOD suggests that clarified influent should be used for nitrifying biofilm processes, total BOD<20 mg/L. Trough dissolved oxygen profiles were not correlated to nitrification.

ISSN:1061-4303    

DOI:10.2175/WER.64.5.10

出版商:Water Environment Research Foundation (WERF)    

年代:1992

数据来源: WILEY