bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of bicarbonate and total volatile acid concentration in anaerobic digesters using a simple titration
Authors: Anderson G. K. , Yang G.
Published: February 2012

ABSTRACT:  A simple, alkalimetric method is described that can be used to determine bicarbonate and total volatile fatty acid concentrations in anaerobic digesters by a two‐stage sequential titration. The new method was evaluated by standard solutions of volatile fatty acids and bicarbonate over a pH 5.5 to 7.65 range. It was also used to determine the total volatile fatty acid and bicarbonate concentrations in effluent samples from five laboratory anaerobic digesters treating different types of waste. The average recovery of volatile fatty acids and bicarbonate by the new method from standard solutions was found to be 96%. The total volatile fatty acid concentration measured by the new method from the digester ceffluent samples coincided well with those measured by a chromatographer.
Use of dilatometric and drying techniques for assessing sludge dewatering characteristics
Authors: Robinson Joseph , Knocke William R.
Published: February 2012

ABSTRACT:  Various methods have been used to characterize the water distribution present in waste sludge samples. This study investigated constant temperature (35°C) drying and dilatometric techniques for quantifying the bound water content of sludges. Preference was stated for the use of dilatometric methods. Bound water content decreased following polymer or freeze‐thaw conditioning of waste chemical and biological sludges. Also, mechanical dewatering produced a significant decrease in bound water content and corresponding increase in dewatered cake solids concentration. Interstitial water was found to have a key role in defining dewatered cake solids concentrations.
Effects of biologically produced surfactants on the mobility and biodegradation of petroleum hydrocarbons
Authors: Falatko David M. , Novak John T.
Published: February 2012

ABSTRACT:  A laboratory investigation was conducted to determine the effects of biologically produced surfactants (biosurfactants) on the solubility and biodegradation of petroleum hydrocarbons. Biosurfactants have been found to be produced by microorganisms during growth on insoluble organic substrates for the purpose of increasing substrate solubility so as to promote biological degradation. In this study, biosurfactants were produced by microorganisms during growth on two substrate groups, gasoline and a mixture of glucose with vegetable oil. Solubilization and biodegradation of selected gasoline compounds in the presence of biosurfactants were measured in both static batch and flow through column systems. Biosurfactants produced and used in this study acted similarly to commercial surfactants by increasing the solubility of gasoline compounds. Biosurfactants produced from growth on glucose and vegetable oil were effective at increasing the solubility of gasoline compounds but they inhibited biological degradation of these same compounds. Biosurfactants produced by microorganisms from growth on gasoline were also effective at increasing solubility but did not inhibit biodegradation. Laboratory column studies indicated that the effectiveness of biosurfactants for soil or groundwater remediation could be limited by the adsorption of the biosurfactant to soil.
Least‐squares calibration of QUAL2E
Authors: Little Keith W. , Williams Randall E.
Published: February 2012

ABSTRACT:  In recent years, much research has been directed toward developing objective, statistically valid methods for water quality model calibration (parameter estimation). Few of these methods have found their way into routine practice. This paper describes the application of a nonlinear regression technique to calibrate the popular water quality model, QUAL2E. A nonlinear programming model was developed to minimize the sum of squares of differences in model predictions and pollutant observations. QUAL2E is called as a subroutine by the program. Six parameters are simultaneously estimated for each of two intensive survey data sets. Because optimal parameter estimates were found to be considerably different for each data set, suggesting that the parameters were not true constants, these estimates were used to develop probability distributions for the parameters for use in a Monte Carlo model.
Air emission studies of sewage sludge incinerators at the Western Branch wastewater treatment plant
Authors: Hentz Lawrence H. , Johnson Floyd B. , Baturay Allen
Published: February 2012

ABSTRACT:  Comprehensive air emission tests were conducted on two multiple‐hearth incinerators equipped with venturi scrubbers, aftercoolers, and zero‐hearth afterburners. A pilot wet electrostatic precipitator was also tested for its ability to reduce emissions from existing systems. Particulate matter, metals, organics, and acid gas emissions were measured by rigorous test procedures. Tests of existing systems indicated that the equipment was capable of reducing particulate emissions to less than 0.38 kg/Mg of dry sludge input. More than half of the particulate mass penetrating the existing equipment was less than 0.6 µm in diameter. Analysis indicated these submicron particles were enriched with volatile metals. The existing equipment demonstrated cadmium and lead control efficiencies that were significantly higher than those assumed in proposed regulations. Despite low sludge concentrations and high site‐specific control efficiencies, arsenic and cadmium emissions will exceed limits proposed in recent regulations. Dispersion factor corrections or reductions in cadmium and arsenic emissions will be needed to satisfy proposed regulations. Emission tests indicated that a wet electrostatic precipitator can greatly enhance the removal of particulate matter, metals, and total hydrocarbons that penetrated the existing systems.
Selection and full‐scale use of a chelated iron absorbent for odor control
Authors: Mansfield Lee A. , Melnyk Peter B. , Richardson George C.
Published: February 2012

ABSTRACT:  Odors had been a chronic operational problem at the City and County of Honolulu's Sand Island W W T P since it began service in 1979. A field survey identified the release of hydrogen sulfide as the major odor source and concluded that off‐gas collection and treatment afforded the best methods for abatement. A pilot program was initiated that tested caustic scrubbing and a chelated iron catalytic absorbent. The latter was selected based on performance, economics, and chemical‐handling requirements. The full‐scale system was designed to treat 10.9 m3/s (23 000 scfm) of air and achieve a 95% reduction in hydrogen sulfide levels, which were expected to range from an average of 75 ppm (V/V) to a peak of 150 ppm. The design used two fiberglass packed towers operating in series followed by activated carbon adsorbers. The system has been in service since June 1986 and has shown itself to be effective in controlling odors.
Treatment of a high‐strength, mixed phenolic waste in an SBR
Authors: Brenner Asher , Chozick Robert , Irvine Robert L.
Published: February 2012

ABSTRACT:  Biological degradation of a synthetic mixture of several phenolic compounds typically found in coal conversion wastes was investigated in the sequencing batch reactor (SBR). The mixture contained phenol; o‐, m‐, and p‐cresols; and 2,3and 3,4‐dimethylphenols and had a total chemical oxygen demand (COD) concentration of 7750 mg/L. A variety of aerobic and anoxic control strategies were tested. A strategy that included an extended anoxic period resulted in the accumulation of byproducts that adversely affected removal efficiency and overall performance. In general, however, COD removal efficiencies were greater than 99%, with effluent COD concentrations averaging between 30 and 52 mg/L. Overdesign of the SBR (that is, hydraulic retention times in excess of that required for COD removal) resulted in the development of filamentous bacteria and poor settling characteristics in the reactor. This problem was eliminated or controlled either by introducing a short anoxic fill period or increasing the organic load. Removal patterns indicative of diauxic growth were observed. Conventional design approaches based on overall COD removal patterns and organic load must be applied cautiously and in conjunction with the removal patterns for individual components when used to design facilities that treat multicomponent toxic wastes.
Effects of reactor configuration and biomass activity on the performance of upflow static media anaerobic reactors
Authors: Chiang Chow‐Feng , Dague Richard R.
Published: February 2012

ABSTRACT:  Three upflow, static‐media anaerobic reactors (USMARs), each with clean‐bed volumes of 85 L but with different heights: diameter ratios were operated at 35°C, with C O D loadings varying from 1 to 12 g/ L · d. Height‐to‐diameter ratios investigated were 1.2, 4.1, and 14.3. The reactors were fed a synthetic substrate made from nonfat dry milk and minerals. It was hypothesized that the effect of biogas mixing on reactor performance would be greater in tall reactors than in short ones. This was found not to be the case. Based on COD removal, the tall reactor performed only slightly better than the shorter ones at loadings less than 9g/L·d. At higher COD loadings, there was no significant difference in performance. Tracer studies using lithium chloride indicated a completely mixed flow regime at COD loadings in excess of 9g/L·d. The acetogenic methanogenic activity of the VSS in all reactors varied between 0.1 and 0.2 L CH4/g VSS · d at reactor VSS concentrations higher than 1000 mg/L.
Effluent toxicity testing using nitrifiers and Microtox™
Authors: Arbuckle W. Brian , Alleman James E.
Published: February 2012

ABSTRACT:  In an effort to develop a less expensive method of assessing wastewater toxicity, two bacterial alternatives to Ceriodaphnia were tested: the commercially available Microtox™ procedure (using Photobacterium phosphoreum) and a nitrifier respiration procedure. Forty‐four biologically treated municipal wastewaters were evaluated. Neither the Microtox nor the nitrifier test is sufficiently sensitive to detect acute Ceriodaphnia toxicity when testing biologically treated municipal wastewaters. The 7‐day chronic Ceriodaphnia procedure is more sensitive than the 48‐hour acute Ceriodaphnia test, with 14 of the 16 wastewaters tested for chronic toxicity exhibiting toxicity using 100% wastewater.
Effect of chemical oxidation on anaerobic biodegradation of model phenolic compounds
Authors: Wang Yi‐Tin
Published: February 2012

ABSTRACT:  The potential for using chemical oxidation to enhance anaerobic biodegradability and reduce toxicity of two model phenolic compounds (o‐cresol and 2,4‐DNP) was evaluated. Batch bioassays were performed on the model compounds and their oxidation samples to determine biodegradability and toxicity in batch methanogenic cultures. Ozone, hydrogen peroxide, and potassium permanganate were the three oxidants examined in this study. A dose of approximately 5 moles hydrogen peroxide, in the presence of a ferrous iron catalyst (Fenton's reagent), 4.5 moles permanganate, or 25 moles of ozone per mole of o‐cresol was needed to significantly enhance anaerobic biodegradability of oxidation samples. Approximately 2.5‐4.5 moles of hydrogen peroxide or 7 moles of ozone per mole of 2,4‐DNP reduced methanogenic toxicity by 50%.
Fate of alachlor and atrazine in a riparian zone field site
Authors: Paterson Kurtis G. , Schnoor Jerald L.
Published: February 2012

ABSTRACT:  A field site was established and instrumented in Amana, Iowa to investigate the fate and transport of the pesticides alachlor and atrazine in the unsaturated zone adjacent to a drainage lake. The pesticides were applied to a barren plot, a plot planted with corn, and a plot planted with deep‐rooted poplar trees (Populus spp.) to study the characteristic behaviors of a typical agricultural environment (corn plot) and a novel pollutant interception technique (poplar plot) in comparison to unmanaged land (barren plot). A mass balance model was developed and solved for the pesticides on each of the three plots. While the majority of alachlor and atrazine adsorbed to the soil and eventually degraded or accumulated in the unsaturated zone, portions of the pesticides remained in the aqueous phase and subsequently were transported in the surface runoff and to the water table. Alachlor was found to be more mobile and more quickly transformed than atrazine. Plant uptake was an important process in the fate of the pesticides, and hence, vegetative buffer strips hold promise for protecting water supplies.
Removal of arsenic from wastewater using chemical precipitation methods
Authors: Harper Thomas R. , Kingham Neville W.
Published: February 2012

ABSTRACT:  The use of arsenic in agriculture, industry, and domestic endeavors since the last century has increased the concentration of arsenic in the environment. During cleanup activities at a former pesticide facility, water that was collected during various operations was contaminated with arsenic and required treatment before discharge. Chemical precipitation was identified as being the most effective means of treatment. Bench‐scale treatability testing was completed to determine the effectiveness of various coagulants, including ferric chloride, hydrated lime, sodium sulfide, and alum. A combination of hydrated lime and ferric chloride was able to remove more than 99% of the original arsenic concentration. Contaminated water to be treated by the full‐scale system had arsenic concentrations up to 48 mg/L. The discharge limitation required that the arsenic concentration be reduced to less than 1 mg/L. More than 605 000 L (160 000 gal) of water were treated using a combination of chemical precipitation, filtration, and carbon absorption.
Underflow geometry in secondary sedimentation
Authors: Samstag Randal W. , Dittmar David F. , Vitasovic Zdenko , McCorquodale J. Alex
Published: February 2012

ABSTRACT:  Previous work by the authors suggested that activated sludge sedimentation might be highly sensitive to underflow geometry. Field, physical model, and stratified flow numerical model tests were conducted to evaluate this hypothesis. Field work included solids settling velocity, dye dispersion, and flow pattern/solids distribution tests. Physical tests included operation of a pie‐shaped 1:12.5 scale model of a circular, center‐feed tank with sludge withdrawal simulating countercurrent, uniform, and cocurrent geometries. A stratified flow numerical model that simulated the effects of density currents was calibrated to the results of the full‐scale testing. The results failed to confirm the experimental hypothesis. Model performance was relatively insensitive to underflow geometry in a circular tank when density effects were simulated.
HIV survivability in wastewater
Authors: Casson Leonard W. , Sorber Charles A. , Palmer Richard H. , Enrico Amy , Gupta Phalguni
Published: February 2012

ABSTRACT:  Acquired Immune Deficiency Syndrome (AIDS) is one of the major health concerns in the world today. The Human Immunodeficiency Virus (HIV), the virus that causes AIDS, has been identified in body fluids and excretions from infected individuals. These body fluids and excretions may result in the presence of HIV in raw wastewater. The objective of this research was to determine the survivability of HIV in raw wastewater and wastewater that had been subjected to various degrees of treatment. To accomplish this objective, wastewater samples were collected, inoculated with known concentrations of HIV, and held at room temperature for up to 72 hours before concentration and assay. Results presented in this paper indicate that infectious HIV is fairly stable in wastewater for up to 12 hours but experiences a 2 to 3‐log reduction in infectivity after 48 hours. When compared to poliovirus under similar conditions, HIV survival was significantly less.
Advective transport in activated sludge flocs
Authors: Li Dahong , Ganczarczyk Jerzy
Published: February 2012

ABSTRACT:  The liquid flow through activated sludge floes from fullscale conventional treatment plants was evaluated on the basis of the information obtained from settling tests. In the samples of the mixed liquors studied, only a part of the activated sludge flocs was found permeable to fluid drainage. Basically, small flocs were not permeable but all the flocs in the size range from 100‐150 μm showed different degrees of permeability. The permeability of flocs increased with an increase in the dynamic sludge age and decreased with an increase in the shear rate measured as the mean velocity gradient in the aeration tanks. The most sensitive assumption for the estimation of the permeability of the flocs was the size of the primary particles in the aggregates, with the sphericity of the flocs being less important. It was also found that the CarmanKozeny model reflected well the porosity‐permeability relationship of most activated sludge flocs, except those that contained substantial amounts of filamentous growth. During free gravitational settling, flocs with the longest dimensions in the size range of 50 to 1000 showed a drainage rate in the range of 102 to 107 μm3/s, which followed the Carman‐Kozeny model with a power relationship of 4.08.
Modeling of best management practices on North Reelfoot Creek, Tennessee
Authors: Moore Larry W. , Chew Chee Y. , Smith Roger H. , Sahoo Surya
Published: February 2012

ABSTRACT:  The Hydrological Simulation Program in FORTRAN (HSPF) was used to evaluate the proposed implementation of various best management practices (BMPs) to reduce erosion and sedimentation. The nonpoint source model, which was previously calibrated and verified, was adjusted to account for changes in model parameters affected by proposed BMP scenarios. BMPs included conversion of cropland to grassland (BMP #1), conservation tillage systems (BMP #9), and reservoir construction (BMP #12). BMP #1 achieved the greatest reduction in watershed erosion and stream sediment loads, while BMP #9 provided only moderate reductions. Construction of three new reservoirs in the 146‐km2 basin provided approximately 50% of the reduction in stream sediment loads as BMP #1. The most cost‐effective approach was BMP #1.
The effect of particulate organic matter on biofilm nitrification
Authors: Figueroa Linda A. , Silverstein JoAnn
Published: February 2012

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.
A modeling approach for VOC emissions from sewers
Authors: Corsi Richard L. , Chang Daniel P. Y. , Schroeder Edward D.
Published: February 2012

ABSTRACT:  Experimental and computational studies were completed to assess volatile organic compound (VOC) emissions from wastewater collection systems. Deuterated chloroform solutions were released into two operating collection systems as a VOC tracer. Downstream sampling of the sewer headspace and wastewater was performed and samples were analyzed by mass spectrometry. Results were used to evaluate a twophase finite volume model for VOC interphase mass transfer and emissions for uniform reaches in sewers. Differences between predicted and experimental average steady‐state concentrations were less than 30%, quite adequate for emission estimation purposes given other uncertainties in wastewater characteristics. The model described in this paper is intended to serve as a screening tool to identify conditions leading to emissions of VOCs from collection systems. The modeling approach can also serve as a basis for more advanced computational solutions as the knowledge base associated with VOCs in sewers improves.
Analysis of pulp mill effluent contaminants in water, sediment, and fish bile—fatty and resin acids
Authors: Morales Angelina , Birkholz Detlef A. , Hrudey Steve E.
Published: February 2012

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 with t‐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%).
Analysis of pulp mill effluent contaminants in water, sediment, and fish muscle— chlorophenols and related compounds
Authors: Morales Angelina , Birkholz Detlef A. , Hrudey Steve E.
Published: February 2012

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 with t‐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%).
Biodegradation of PCP enhanced by chemical oxidation pretreatment
Authors: Lee Sang H. , Carberry Judith B.
Published: February 2012

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 as Pseudomonas putida and Pseudomonas 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.
Phosphorus sorption by peat and sand amended with iron oxides or steel wool
Authors: James Bruce R. , Rabenhorst Martin C. , Frigon George A.
Published: February 2012

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.
Explaining widely varying biofilm‐process performance with normalized loading curves
Authors: Wirtel Steven A. , Noguera Daniel R. , Kampmeier Daniel T. , Heath Mark S. , Rittmann Bruce E.
Published: February 2012

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.
A sequencing biofilm reactor for the treatment of chlorinated solvents using methanotrophs
Authors: Speitel Gerald E. , Leonard Jean M.
Published: February 2012

ABSTRACT:  Laboratory experiments were conducted with a sequencing, packed‐bed bioreactor that was seeded with the methanotroph, Methylosinus trichosporium OB3b. 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.
The role of oxygen transfer in acid mine drainage (AMD) treatment
Authors: Hustwit Craig C. , Ackman Terry E. , Erickson Patricia E.
Published: February 2012

ABSTRACT:  A study was conducted to evaluate two chemical models of iron oxidation. The first model was proposed by U. S. EPA in 1983 for use in the design of acid mine drainage (AMD) treatment systems. This model expresses the oxidation rate as a function of ferrous iron, oxygen concentrations, and pH. The second model was proposed by the U. S. Bureau of Mines and expresses the oxidation rate as a function of a treatment system's oxygen transfer rate. The findings of the study were that the model based on oxygen transfer was accurate in predicting oxidation rates over a wide range of initial ferrous iron concentrations. The predictions of the EPA model were inaccurate in modeling iron oxidation.
The case for anaerobic reduction of oxygen requirements in biological phosphorus removal systems
Authors: Randall Clifford W. , Brannan Kenneth P. , McClintock Samuel A. , Pattarkine Vikram M.
Published: February 2012

ABSTRACT:  Laboratory and pilot‐plant scale studies were conducted to investigate the occurrence of anaerobic reduction of oxygen requirements in excess biological phosphorus removal (BPR) systems. The investigation was accomplished through application of chemical oxygen demand (COD)/oxygen‐utilization mass balance techniques. Reductions of 0 to approximately 50% in the oxygen required for organic stabilization were achieved during treatment of synthetic and raw wastewaters. The reductions were attributed to stabilization occurring in the anaerobic reactors and represent a potential aeration energy savings that could be realized with BPR systems in addition to any savings associated with denitrification. Factors which influence the occurrence and magnitude of anaerobic stabilization include the composition of the influent wastewater, and the strength of the influent wastewater. It was concluded that substantial reduction of oxygen requirements can occur as a result of anaerobic stabilization and that the principal mechanism is probably metabolism by bacteria, such as fermenters, that do not accumulate phosphorus.
MetPAD™: a bioassay for rapid assessment of heavy metal toxicity in wastewater
Authors: Bitton Gabriel , Koopman Ben , Agami Orna
Published: February 2012

ABSTRACT:  MetPAD™, a bioassay for the specific determination of heavy metal toxicity, was evaluated for toxicity assessment of industrial effluents. It was shown that MetPAD does not respond to organic toxicants, but is sensitive to heavy metals. Six of nine industrial effluents were shown to be toxic using MetPAD. Chemical analyses of the industrial effluents confirmed the presence of heavy metals. If run concurrently with another test for general toxicity test (for example, Microtox™), MetPAD can be a suitable complimentary assay for the specific determination of heavy metal toxicity.
Constructed wetland design—the first generation
Authors: Reed Sherwood C. , Brown Donald S.
Published: February 2012

ABSTRACT:  A recent study for the U. S. EPA documented more than 150 constructed wetland systems in the United States, treating municipal and industrial wastewaters. During 1990 and 1991, visits were made to more than twenty of these sites for observations and discussions with the designers and operators. This first generation of systems demonstrates a lack of consensus on design procedures, and in many cases little regard for some of the critical factors affecting performance. This paper summarizes the results of the inventory and site visits and provides suggestions for design of the second generation of these systems.
Development of an off‐line enricher‐reactor process for activated sludge degradation of hazardous wastes
Authors: Babcock Roger W. , Ro Kyoung S. , Hsieh Chu‐Chin , Stenstrom Michael K.
Published: February 2012

ABSTRACT:  The improvement in degradation of a hazardous chemical using a novel bioaugmentation scheme was studied. Bench‐scale offline batch enricher‐reactors (ERs) maintaining an enrichment culture were used to bioaugment bench‐scale continuous‐flow activated sludge reactors treating 1‐naphthylamine (1NA). In batch experiments, onetime bioaugmentation inoculations of 1, 2, 5, 10, 20, and 50% by mass of a INA‐degrading culture (mg mixed liquor volatile suspended solids [MLVSS] of INA‐degrading culture/mg MLVSS of indigenous culture) increased degradation rates by approximately 0, 33, 100, 100, 100, and 300% respectively over an uninoculated control. In continuous‐flow experiments, separate 13.7‐L reactors received daily inoculations of 1.4, 2.5, 6.6, 11.4, and 18.3% by mass of 1 NA‐degrading culture. Cumulative target compound breakthrough reduction following a 50 mg 1NA/L spike was 13, 21, 11, 35, and 41% compared to an unacclimated control and 4, 13, 1, 27, and 35% compared to an acclimated control, respectively. Similarly, the reduction in breakthrough during reacclimation to 5 mg 1NA/L over six days was 66, 73, 85, 98, and 100%, respectively. A 6% bioaugmented continuous‐flow reactor significantly reduced 1NA breakthrough following a step‐loading increase from 1 to 5 mg 1NA/L compared to an uninoculated control. Effective bioaugmentation was achieved with additions of biomass equivalent to 14‐25% of indigenous cell production rates.
Operating capacity of GAC adsorbers—dissolved oxygen and extended service life
Authors: Vidic Radisav D. , Suidan Makram T.
Published: February 2012

ABSTRACT:  The effect of molecular oxygen on the adsorptive capacity of activated carbon was evaluated in this study. It was determined that the capacity of granular activated carbon (GAC) for o‐cresol under oxic conditions can be more than 2.5‐fold the capacity attainable under anoxic conditions. This increase in the GAC adsorptive capacity under oxic conditions cannot be attributed to biological activity. The observed phenomenon was found to result from carbon mediated polymerization reactions of o‐cresol that occur in the presence of molecular oxygen. The rate of adsorbate polymerization was slower than the rate of adsorption and the presence of molecular oxygen did not affect adsorption kinetics during the initial phase of adsorbent‐adsorbate contact. However, the presence of molecular oxygen was demonstrated to have a significant impact on the breakthrough of o‐cresol from 5 GAC adsorbers operated in series (total bed length = 4 m, total GAC mass = 1 kg). During the first phase of the experiment, which was conducted under anoxic conditions, breakthrough of o‐cresol from all 5 adsorbers was accurately predicted using a plugflow homogeneous surface‐diffusion model and independently determined kinetic and capacity parameters. Furthermore, the effluent profiles collected under anoxic conditions exhibited almost no tailing during the later part of breakthrough as saturation was approached. On introduction of oxygen to this system the effluent o‐cresol concentration dropped significantly (from 200 mg/L to only 6 mg/L). The total exhibited GAC adsorptive capacity for the entire experiment was accurately predicted by the oxic adsorption isotherm.
Microbial dynamics in a continuously stirred tank reactor with 100% cell recycle
Authors: Okaygun Mehmet S. , Akgerman Aydin
Published: February 2012

ABSTRACT:  Effects of continuous cultivation on the dynamics of heterogenous populations were investigated by employing a continuously stirred tank reactor (CSTR) with 100% cell recycle to minimize biomass waste and any shifts in microbial populations. Phenol was used as model substrate and as the sole carbon source. Activated sludge bacteria, acclimated to phenol, were grown in a CSTR with 100% cell recycle operated at the same dilution rate but with different influent phenol concentrations. During the steady state, the kinetic parameters for the Haldane model (µm, Ks, and K1) characterizing growth on phenol were determined by a long‐term batch experiment. The dominant microbial species at each steady state were analyzed by biochemical assays. There was a shift in microbial species at different influent phenol concentrations with a corresponding change in µm values whereas the values of Ks and K1 were not influenced. Even though the changes in microbial populations and kinetic parameters were attributed to changes in the influent phenol concentration, there was no direct correlation between them.
A comparison of surface‐grab and cross sectionally integrated stream‐water‐quality sampling methods
Authors: Martin Gary R. , Smoot James L. , White Kevin D.
Published: February 2012

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.
Effects of biomass entrapment and carrier properties on the performance of an air‐fluidized‐bed biofilm reactor
Authors: Tsubone Toshiaki , Ogaki Yoji , Yoshiy Yuji , Takahashi Masahiro
Published: February 2012

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.
Application of respirometric biodegradability testing protocol to slightly soluble organic compounds
Authors: Aichinger Georg , Grady C. P. Leslie , Tabak Henry H.
Published: February 2012

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, and b) was possible when a compound was present at a concentration below its solubility limit, but estimates of KS could 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.
Strategy for data analysis in environmental surveys emphasizing the index of biotic similarity and BIOSIM1
Authors: Pearson J. Gareth , Pinkham Carlos F. A.
Published: February 2012

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.
Effect of glucose on 2,4‐dinitrophenol degradation kinetics in sequencing batch reactors
Authors: Hess Thomas F. , Silverstein JoAnn , Schmidt Steven K.
Published: February 2012

ABSTRACT:  A Janthinobacterium sp. and a Rhodococcus sp., both capable of mineralizing 2,4–dinitrophenol (DNP), were used as inoculum for activated sludge in bench‐scale sequencing batch reactors (SBRs). Degradation of 10 mg/L of DNP in these SBRs was enhanced to varying degrees by the addition of glucose at concentrations of 50, 100, and 500 mg/L. Addition of 10 mg of glucose/L had no effect, while 1000 mg of glucose/L inhibited DNP degradation. Maximal degradation, based on the rate of DNP degradation per unit of glucose added, was obtained at a glucose concentration of 100 mg/L. A Michaelis‐Menten type saturation rate model was successfully used to model DNP degradation kinetics in the SBRs; comparison of model parameters then allowed us to determine the effect of glucose addition. Also, it was found that the added glucose was associated with an increase in the standing biomass of DNP‐degrading bacteria, probably because of greater retention of this population in the activated sludge. This research demonstrates the usefulness of supplemental carbon substrates for enhancing the degradation of toxic chemicals in bioreactors containing heterogeneous microbial communities.
Anaerobic treatment of thermal sludge conditioning liquor with granular sludge
Authors: Kimata Takashi , Kawai Takehiko , Tada Minoru , Tanaka Kazuhiro , Shinabe Kazuhiro , Shimizu Kou
Published: February 2012

ABSTRACT:  Thermal sludge conditioning liquor was successfully treated by a pilot‐scale upflow anaerobic hybrid system with an effective volume of 10.4 m3. The reactor was similar to the HYAN reactor in Lakeview but without a recirculation system. A gas‐solid separator was installed above a filter packed with polypropylene pall rings. The organic loading rate was increased stepwise to 30 kg chemical oxygen demand (COD)/m3 · d. The hydraulic retention time was only 6 hours at the target loading rate. More than 70% of soluble COD in the influent was removed, even at an organic loading as high as 30 kg COD/m3 · d. Soluble 5‐day biochemical oxygen demand (BOD5) removal efficiency at the loading rate exceeded 95%. Volatile fatty acids concentration in the effluent was consistently less than 60 mg/L after the day when stable treatment had been obtained. The methane production fluctuated between 0.3 and 0.4 L/g COD removed. Solids production including effluent suspended solids (SS) was between 0.16 and 0.24 kg SS/kg COD removed. The inside of the reactor consisted of two zones, a sludge blanket zone with less than 1% solids concentration and a sludge bed zone with 47% solids concentration. Although the reactor was seeded with an anaerobically digested sludge, granular sludge was produced in the reactor. The ratio of granules to the solids remaining in the reactor increased to approximately 70% at the end of the experiments. Most of the granules had diameters of less than 1 mm and their settling velocity was 0.6 cm/s or more. The granules were composed of bacteria like Methanothrix according to SEM observations. The methane production rate was between 0.8 and 1.1 kg methane as COD/kg SS · d in an acetate solution. According to substrates distribution in the reactor and tracer tests, the bed zone in the reactor worked similarly to a continuously stirred tank reactor (CSTR). Evaluation of soluble COD removal rates in the reactor indicated that the rate could be simulated by a Monod type reaction.
Multicomponent adsorption of volatile organic chemicals from air stripper offgas
Authors: Mueller James A. , DiToro Dominic M.
Published: February 2012

ABSTRACT:  Air stripping for the efficient removal of volatile organic chemicals (VOCs) from contaminated groundwater is used in drinking water purification and hazardous waste site remediation. As air quality regulations become more stringent, emission controls such as granular activated carbon (GAC) will be required on the air stripper offgases. Often air stripper‐GAC adsorber interactions are neglected with the air stripper design optimized and the GAC adsorber designed for the resulting offgases, leading to unrealistically high operating costs. This paper presents a multicomponent offgas adsorption model which is used to calculate the carbon breakthrough curves. Due to its generality and ease of application, the Polanyi equilibrium potential theory is used to describe the equilibrium sorption isotherms. These are combined with the hydraulics and mass‐transfer kinetics to calculate chemical breakthrough curves. The model is calibrated using data from a pilot‐scale unit treating a contaminated groundwater containing seven chlorinated VOCs. Application of the model to temperature effects on GAC adsorber design and the impact of regeneration frequency on carcinogenic risk are presented.
Use of inducer compounds in the enricher‐reactor process for degradation of 1‐naphthylamine wastes
Authors: Babcock Roger W. , Stenstrom Michael K.
Published: February 2012

ABSTRACT:  The feasibility of using less hazardous inducer compounds to maintain the ability of an enrichment culture to degrade a hazardous compound was investigated. Bench‐scale (5 L) batch enricherreactors (ERs) maintaining enrichment cultures were used to bioaugment bench‐scale continuous‐flow activated sludge reactors treating 1‐naphthylamine (1NA). Potential inducer compounds tested were 1‐acetatenaphthalene, 1‐naphthoic acid, 1‐naphthalene‐sulfonic acid, and gentisic acid. In batch experiments, subcultures of the original enrichment culture that had been grown on potential inducer compounds for a period of 3 months without 1NA, maintained the ability to degrade 1NA but at reduced rates compared to a control maintained on 1NA. In continuous‐flow experiments, separate 13.7‐L reactors received daily inoculations of 2–4% by mass of INA‐enrichment culture, or 3% by mass of the subcultures maintained on inducer compounds. Target compound breakthrough from augmented reactors was significantly reduced (relative to an acclimated control) following a step‐increase from 1 to 5 mg 1NA/ L, and reintroduction of 5 mg 1NA/L after its absence from the waste stream for 9 days (two separate experiments). A modest reduction of breakthrough was also observed following a 10 mg 1NA/L spike (a separate experiment).