Biodegradation Of Organic Compounds Research Articles

A simple methodology to evaluate influence of H 2O 2 and Fe 2+ concentrations on the mineralization and biodegradability of organic compounds in water and soil contaminated with crude petroleum

Simple measurements of H 2O 2 concentration or CO 2 evolution were used to evaluate the effectiveness of the use of Fenton's reagent to mineralize organic compounds in water and soil contaminated by crude petroleum. This methodology is suitable for application in small treatment and remediation facilities. Reagent concentrations of H 2O 2 and Fe 2+ were found to influence the reaction time and temperature, as well as the degree of mineralization and biodegradability of the sample contaminants. Some H 2O 2/Fe 2+ combinations (H 2O 2 greater than 10% and Fe 2+ greater than 50 mM) resulted in a strong exothermic reaction, which causes peroxide degradation and violent gas liberation. Up to 75% TOC removal efficiency was attained in water and 70% in soil when high H 2O 2 (20%) and low Fe 2+ (1 mM) concentrations were used. Besides increasing the degree of mineralization, the Fenton's reaction enhances the biodegradability of petroleum compounds (BOD 5/COD ratios) by a factor of up to 3.8 for contaminated samples of both water and soil. Our experiments showed that low reagent concentrations (1% H 2O 2 and 1 mM Fe 2+) were sufficient to start the degradation process, which could be continued using microorganisms. This leads to a decrease in reagent costs in the treatment of petroleum-contaminated water and soil samples. The simple measurements of H 2O 2 concentration or CO 2 evolution were effective to evaluate the Fenton's reaction efficiency.

Biochemical Interpretation of Quantitative Structure−Activity Relationships (QSAR) for Biodegradation of N-Heterocycles: A Complementary Approach to Predict Biodegradability

Prediction of the biodegradability of organic compounds is an ecologically desirable and economically feasible tool for estimating the environmental fate of chemicals. We combined quantitative structure-activity relationships (QSAR) with the systematic collection of biochemical knowledge to establish rules for the prediction of aerobic biodegradation of N-heterocycles. Validated biodegradation data of 194 N-heterocyclic compounds were analyzed using the MULTICASE-method which delivered two QSAR models based on 17 activating (OSAR 1) and on 16 inactivating molecular fragments (GSAR 2), which were statistically significantly linked to efficient or poor biodegradability, respectively. The percentages of correct classifications were over 99% for both models, and cross-validation resulted in 67.9% (GSAR 1) and 70.4% (OSAR 2) correct predictions. Biochemical interpretation of the activating and inactivating characteristics of the molecular fragments delivered plausible mechanistic interpretations and enabled us to establish the following biodegradation rules: (1) Target sites for amidohydrolases and for cytochrome P450 monooxygenases enhance biodegradation of nonaromatic N-heterocycles. (2) Target sites for molybdenum hydroxylases enhance biodegradation of aromatic N-heterocycles. (3) Target sites for hydratation by an urocanase-like mechanism enhance biodegradation of imidazoles. Our complementary approach represents a feasible strategy for generating concrete rules for the prediction of biodegradability of organic compounds.

Fate of major compounds in source-separated urine

Urine separation is a promising alternative to present-day waste water management. It can help to manage our nutrient flows in a sustainable way. Currently, techniques are being developed to recycle and treat source-separated urine. These techniques, however, must consider the spontaneous processes that change the separated urine. The initial cause of changes is the contamination with microorganisms, which can hardly be avoided in urine-collecting systems. The most important transformation processes are microbial urea hydrolysis, mineral precipitation and ammonia volatilisation. Additionally, a variety of microorganisms may grow in source-separated urine, because the content of biodegradable organic compounds is very high. These microorganisms may also include pathogens. In this paper we give an overview of the effects that the spontaneous transformation processes may have. We focus on nitrogen, phosphorus, magnesium, calcium, potassium, sulphur, organic substances, pathogens and the buffering capacity. The discussion is based on own experiences and literature reviews. This overview will help to develop appropriate technologies for urine recycling.

Persistence of Fermentative Process to Phenolic Toxicity in Groundwater

The fermentation process is an important component in the biodegradation of organic compounds in natural and contaminated systems. Comparing with terminal electron-accepting processes (TEAPs), however, research on fermentation processes has to some extent been ignored in the past decades, particularly on the persistence of fermentation process in the presence of toxic organic pollutants. Both field and laboratory studies, presented here, showed that microbial processes in a groundwater-based system exhibited a differential inhibitory response to toxicity of phenolic compounds from coal tar distillation, thus resulting in the accumulation of volatile fatty acids (VFAs) and hydrogen. This indicated that fermentation processes could be more resistant to phenol toxicity than the subsequent TEAPs such as methanogenesis and sulfate reduction, thus providing us with more options for enhancing bioremediation processes.

Removal of organic compounds from municipal landfill leachate in a membrane bioreactor

Landfill leachate is highly loaded, toxic and is bad for the sanitation of wastewater. The management of leachate can be carried out by applying treatment or pre-treatment, recirculation (spraying), evaporation to the solid phase and discharge into sewer systems or transfer to a wastewater treatment plant. Research is presented into the biodegradation of leachate collected from the municipal landfill in Gliwice, which was added to a medium that simulated municipal wastewater. The tests were carried out in two systems: a laboratory bioreactor with activated sludge and a membrane bioreactor. The biodegradation of organic compounds was assessed on the basis of reduction in the contaminants denoted by BOD, COD, TOC and changes in IC. The results revealed a considerable impact of the amount of added leachate (2.5, 5 and 10%) on the effectiveness of biodegradation. The application of membrane operations instead of the conventional secondary tank enhanced the treatment of wastewater that contained municipal landfill leachate.

Textile sludge application to non-productive soil: Physico-chemical and phytotoxicity aspects

As part of an assessment study on the risk of spreading textile sludge onto non-productive soil, the sorption behaviour of some sludge-metal constituents [Cr(VI), Cu(II), Pb(II), and Zn(II)] in the soil was studied. In addition, the sludge stabilization effect was evaluated by the biodegradation of organic compounds and phytotoxicity tests. Metal–soil sorption was assessed using soil columns and by sorption isotherms (i.e., Freundlich and Langmuir). In relation to the phytotoxicity of Eruca sativa L., there was a biomass inhibitory effect for the fresh sludge and a biomass stimulant effect for the stabilized sludge. Thus our results show that after stabilization, the tested loading ratio of 33% sludge: 67% soil (v/v) (equivalent to 85 Mg ha −1) did not significantly increase the risk of groundwater contamination since only small amounts of metals applied to the soil underwent percolation and almost all the organic compounds were degraded.

Stygofauna Abundance and Distribution in the Fissures and Caves of the Nardò (Southern Italy) Fractured Aquifer Subject to Reclaimed Water Injections

The demographic growth in developing countries and the increasing pressure of anthropological activities in industrialized states around the world, are leading to a gradual contamination of the natural habitats of our planet. Although the extent of these effects is unclear, the results can already seen in the quality of natural resources, which are intensely stressed by climate changes (greenhouse effect, nutrients load, water consumption, etc.) and by direct contamination of toxic wastes. This could progressively destroy the variety of faunal species and, indeed, recent warming has caused changes in species distribution and abundance. This paper presents an investigation into the possible effects of climate change and anthropological pressures on the ground water fauna present at the Nardò site (Salento peninsula, Southern Italy). Three ecological categories were examined: stygoxenes, stygophiles and stygobionts. The latter are anophthalmic, without pigment, measure up to 10–12 mm, and live in water which moves throughout fissures and karstic caves of carbonate aquifers. These stygofauna are very sensitive to changes, due to environmental stresses, such as water temperature, dissolved oxygen, water salinity, pH and chemical constituents, in their hypogeous habitat. The stygofauna categories are active organisms which contribute to the biodegradation of organic compounds in wastewater artificially (or naturally) injected in the fractured subsoil. Weak information has been available until now about Salento stygofauna ability to resist water pollution caused by human activities. At the Nardò site 12000 m3/d of 2 y effluent from municipal treatment plants have been injected since 1991 in a natural sinkhole. Here, the abundance of the stygofauna, recovered in three wells (Colucci, Brusca and Spundurata cave) at progressive distances from sinkhole, and their distribution have been correlated with ground water constituents. Groundwater quality was monitored on each occasion that stygofauna were collected, during the spring-autumn seasons.

Diversity and Biocatalytic Potential of Epoxide Hydrolases Identified by Genome Analysis

Epoxide hydrolases play an important role in the biodegradation of organic compounds and are potentially useful in enantioselective biocatalysis. An analysis of various genomic databases revealed that about 20% of sequenced organisms contain one or more putative epoxide hydrolase genes. They were found in all domains of life, and many fungi and actinobacteria contain several putative epoxide hydrolase-encoding genes. Multiple sequence alignments of epoxide hydrolases with other known and putative alpha/beta-hydrolase fold enzymes that possess a nucleophilic aspartate revealed that these enzymes can be classified into eight phylogenetic groups that all contain putative epoxide hydrolases. To determine their catalytic activities, 10 putative bacterial epoxide hydrolase genes and 2 known bacterial epoxide hydrolase genes were cloned and overexpressed in Escherichia coli. The production of active enzyme was strongly improved by fusion to the maltose binding protein (MalE), which prevented inclusion body formation and facilitated protein purification. Eight of the 12 fusion proteins were active toward one or more of the 21 epoxides that were tested, and they converted both terminal and nonterminal epoxides. Four of the new epoxide hydrolases showed an uncommon enantiopreference for meso-epoxides and/or terminal aromatic epoxides, which made them suitable for the production of enantiopure (S,S)-diols and (R)-epoxides. The results show that the expression of epoxide hydrolase genes that are detected by analyses of genomic databases is a useful strategy for obtaining new biocatalysts.

Organic compounds in re-circulated leachates of aerobic biological treated municipal solid waste

Biodegradation of organic matter is required to reduce the potential of municipal solid waste for producing gaseous emissions and leaching contaminants. Therefore, we studied leachates of an aerobic-treated waste from municipal solids and a sewage sludge mixture that were re-circulated to decrease the concentration of biodegradable organic matter in laboratory-scale reactors. After 12 months, the total organic C and biological and chemical oxygen demands were reduced, indicating the biodegradation of organic compounds in the leachates. Curie-point pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and pyrolysis-field ionization mass spectrometry (Py-FIMS) revealed that phenols, alkylaromatic compounds, N-containing compounds and carbohydrates were the predominate compounds in the leachates and solid waste. Leachate re-circulation led to a higher thermal stability of the residual organic matter as indicated by temperature-resolved Py-FIMS. Admixture of sewage sludge to solid waste was less effective in removing organic compounds from the leachates. It resulted in drastic higher and more bio-resistant loads of organic matter in the leachates and revealed increased proportions of alkylaromatic compounds. The biodegradation of organic matter in leachates, re-circulated through municipal solid waste, offers the potential for improved aerobic waste treatments and should be investigated on a larger scale.

Effect of Modified Fenton’s Reaction on Microbial Activity and Removal of PAHs in Creosote Oil Contaminated Soil

This study describes the removal of polycyclic aromatic hydrocarbons (PAHs) from creosote oil contaminated soil by modified Fenton's reaction in laboratory-scale column experiments and subsequent aerobic biodegradation of PAHs by indigenous bacteria during incubation of the soil. The effect of hydrogen peroxide addition for 4 and 10 days and saturation of soil with H(2)O(2) on was studied. In both experiments the H(2)O(2) dosage was 0.4 g H(2)O(2)/g soil. In completely H(2)O(2)-saturated soil the removal of PAHs (44% within 4 days) by modified Fenton reaction was uniform over the entire soil column. In non-uniformly saturated soil, PAH removal was higher in completely saturated soil (52% in 10 days) compared to partially saturated soil, with only 25% in 10 days. The effect of the modified Fenton's reaction on the microbial activity in the soil was assessed based on toxicity tests towards Vibrio fischeri, enumeration of viable and dead cells, microbial extracellular enzyme activity, and oxygen consumption and carbon dioxide production during soil incubation. During the laboratory-scale column experiments, the toxicity of column leachate towards Vibrio fischeri increased as a result of the modified Fenton's reaction. The activities of the microbial extracellular enzymes acetate- and acidic phosphomono-esterase were lower in the incubated modified Fenton's treated soil compared to extracellular enzyme activities in untreated soil. Abundance of viable cells was lower in incubated modified Fenton treated soil than in untreated soil. Incubation of soil in serum bottles at 20 degrees C resulted in consumption of oxygen and formation of carbon dioxide, indicating aerobic biodegradation of organic compounds. In untreated soil 20-30% of the PAHs were biodegraded during 2 months of incubation. Incubation of chemically treated soil slightly increased PAH-removal compared to PAH-removal in untreated soil.

S–O–C isotopic picture of sulphate–methane–carbonate system in freshwater lakes from Poland. A review

Microbial oxidation of organic compounds (including methane), in freshwater sediments, may result in precipitation of carbonates, which may become an important geochemical archive of paleoenvironmental variations. Most probably low δ13C value in calcite in eutrophic systems results from an advanced oxidation of organic compounds in turbulent or/and sulphate-rich conditions. Likewise, high δ13C value in calcite from organic-rich sediments may evidence low redox potential of the freshwater system. Oxidation of methane and organic matter results in significant isotope effects in sulphates dissolved in water. Therefore, to better understand the origin of carbon isotope signal in carbonates, concentration and stable isotope measurements in dissolved sulphate (water column), bubble methane and calcite (freshwater sediments) have been carried out in 24 lakes, 2 ponds and 4 rivers in Poland. The highest concentration of sulphate has been detected in rivers (85.47 SO42− mg/l) and an artificial lake (70.30 SO42− mg/l) located in the extremely SO42−-polluted region called the “Black Triangle”. The lowest concentration of sulphate is found in dystrophic and mountain lakes (from 0.5 SO42− to about 3 mg/l). The lowest δ34S(SO42−) and δ18O(SO42−) values occur in unpolluted lakes in eastern Poland (−0.94 and 1.38‰, respectively). The highest S and O isotopic ratios are found in a polluted lake in western Poland (δ14S(SO42)=12.95‰) and in a dystrophic lake in eastern Poland (δ18O(SO42) = 16.15‰) respectively. It is proposed that δ34SO42− and (18O(SO42−) values in lakes represent a good tool to assess and quantify anthropogenic impact by acid precipitation and to monitor variations in the trophic state and redox processes controlled by biodegradation of organic compounds in sediments and water column. In general, increasing depth (up to 12 m) of the water column is associated with decreasing trend the δ13C(CH4) value from about –35 to about –78‰. However, δ13C value in sedimentary calcite (δ13C vary from –10 to 0.5‰) shows opposite trends as compared to the corresponding methane. This is probably due to redox processes and distribution of heavy isotopes between methane and calcite. Likewise, turbulent water (river) show high δ13C value in methane and low δ13C value in calcite—this is probably due to an enhanced oxidation of methane producing 13C-depleted CO2. In contrast to clean lakes, it is observed that an increase of the δ13C(CH4) value occurs with increasing depth of the water column in a strongly SO42−-contaminated lake. This is probably due to a loss of biological buffering potential of the lake accompanied by an active oxidation of methane precursors.

Coupling ultraviolet photolysis and biofiltration for enhanced degradation of aromatic air pollutants

AbstractCoupling UV photolysis and biofiltration was evaluated as an effective treatment strategy for the enhanced degradation of hardly biodegradable aromatic volatile organic compounds (VOCs). o‐Xylene, a recalcitrant and poorly water‐soluble VOC, was used as a model compound and treated in two parallel treatment systems with and without UV pretreatment. Contaminated streams with flow rates of 0.186–0.384 m3 h−1 and inlet o‐xylene concentrations of up to 0.22 g m−3 were passed through the treatment system. About 20% (between 10 and 35%) of o‐xylene was converted into water‐soluble intermediates during the UV photolysis stage, which partially oxidized o‐xylene to more water‐soluble and biodegradable byproducts. The untreated contaminant along with the byproducts of UV photolysis was then removed effectively in the biofiltration stage, with improvements of up to 100% compared with the control biofiltration process. The results suggested that combined UV photolysis–biofiltration is promising as an effective technique to eliminate hydrophobic and recalcitrant organic compounds from contaminated air steams. Copyright © 2005 Society of Chemical Industry

Development of a hybrid ozonation biofilm-membrane filatration process for the production of drinking water

Drinking water sources in Norway are characterized by high concentrations of natural organic matter (NOM), low alkalinity and low turbidity. The removal of NOM is therefore a general requirement in producing potable water. Drinking water treatment plants are commonly designed with coagulation direct filtration or NF spiral wound membrane processes. This study has investigated the feasibility and potential of a hybrid process combining ozonation and biofiltration with a rotating disk membrane for treating drinking water with high NOM concentrations. Ozonation will oxidize the NOM content removing colour and form biodegradable organic compounds, which can be removed in biological filters. A constructed water was used in this study which is representative of ozonated NOM-containing water. A rotating membrane disk bioreactor downstream the ozonation process was used to carry out both the biodegradation as well as biomass separation in the same reactor. Maintenance of biodegradation of the organic matter while controlling biofouling of the membrane and acceptable water production rates was the focus in the study. Three operating modes were investigated. Removal of the biodegradable organics was consistent throughout the study indicating that sufficient biomass was maintained in the reactor for all operating conditions tested. Biofouling control was not achieved through shear-induced cleaning by periodically rotating the membrane disks at high speed. By adding a small amount of sponges in the membrane chamber the biofouling could be controlled by mechanical cleaning of the membrane surface during disk rotation. The overall results indicate that the system can favorably be used in an ozonation/biofiltration process by carrying out both biodegradation as well as biomass separation in the same reactor.

Biodegradability oriented treatability studies on high strength segregated wastewater of a woolen textile dyeing plant

Textile dyeing and finishing industry involves considerable amount of water usage as well as polluted and highly colored wastewater discharges. Biological treatability by means of mineralization, nitrification and denitrification of high strength woolen textile dye bathes, first- and second-rinses is presented. COD fractionation study was carried out and kinetic parameters were determined. Biodegradability of organic compounds in highly loaded composite wastewater after segregation and the effluent of applied biological treatment of high strength composite wastewater were measured by determining oxygen consumption rates. The results were used in terms of assessing an alternative method for inert COD fractionation. The study implied that about 80% soluble COD, 50% color and 75% toxicity reduction were possible by single sludge biological processes. Sixteen per cent of total COD was found to be initially inert. Inert fraction was increased to 22% by production of soluble and particulate microbial products through biological treatment.

Short-term BOD (BOD st) as a parameter for on-line monitoring of biological treatment process : Part I. A novel design of BOD biosensor for easy renewal of bio-receptor

A novel design of a biochemical oxygen demand (BOD) biosensor has been developed for on-line monitoring of easily biodegradable organic compounds in aqueous samples. The biological recognition element of the sensor could be easily renewed by injecting new bacterial paste without disassembling the sensor system. The sensor measurements were carried out in the initial-rate mode using a flow injection (FI) system, resulting in 60 s for one sample analysis followed by a recovery time less than 10 min. The sensor performance achieved showed a wide detection linearity over the range of 5–700 mg BOD 5·l −1 and a generally good agreement between the BOD values estimated by the biosensor and the conventional 5-day test. Furthermore, the precision test was in the control range (i.e. repeatability ≤ |±7.5%|, reproducibility ≤ |±7.3%|). The sensor could be used over 1 week in continuous test, however, the best performance was found within the first 24 h where standard deviation of the sensor response was ±2.4%. The design of the sensor allows easy and fast renewal of the cells used as sensing elements. Replacement of biological recognition element and calibration of the sensor responses can be performed in a rather simple procedure on a daily regular basis. By using a mixed culture as the bio-receptor, one gets a sensor that reacts to a wide range of substrates. The new sensor construction will thus allow fast and convenient replacement of the bio-receptor and on-line assay of a broad range of substrates. This makes the sensor being an interesting and promising candidate for on-line monitoring of biological treatment process.

Modelling and experimental investigation of environmental influences on the acetate and methane formation in solid waste

An anaerobic reaction model is represented and used for simulation of the biodegradation of organic compounds and the generation of biogas. The model is based on fundamental relationships among physical, chemical, thermodynamic and microbial processes occurring in municipal landfills. Local microbially mediated degradation processes occurring in municipal landfills are simulated in terms of hydrolysis of readily and inherently degradable organic matter, the formation of acetate as surrogate for intermediary low-molecular carbon substrates, and the generation of the biogases CH 4 and CO 2. Thus, the overall decomposition of the organic matter has been assumed to follow three sequential anaerobic reactions steps: hydrolysis, acetogenesis and methanogenesis. In order to study the impact of environmental factors on the biological decomposition processes, experiments have been conducted to investigate the effect of temperature and water content. In the degradation model, the impact of temperature and water content was defined as reaction rate influencing factors. Further, waste samples have been taken from four drill holes on a municipal landfill near Wolfsburg (Germany) and used to analyze and to describe the waste composition and prevailing environmental conditions dependent on the depth of the drill hole. The data and waste samples obtained from the landfill have also been used for model development and validation.

Mass transfer analysis of a membrane aerated reactor

The membrane aerated reactor has proven suitable, in laboratory scale studies, for high-rate organic carbonaceous pollutant oxidation, volatile organic compound biodegradation, and as a single-stage bioreactor for simultaneous organic carbonaceous pollutant removal, nitrification and denitrification. In this work, a mathematical model of oxygen and methane transfer through a dense silicone membrane in such a reactor system is presented. Mass transfer coefficients are determined under a variety of different conditions and the impact of operating parameters, including oxygen and methane partial pressure, and various gas–liquid concentrations, on oxygen transfer is investigated.

Volatile fatty acid formation in an anaerobic hybrid reactor

A laboratory scale model reactor was used to investigate volatile fatty acid (VFA) formation during anaerobic degradation in an anaerobic hybrid reactor. The purpose of the study was to determine the role of upflow anaerobic sludge blanket (UASB) and anaerobic filter (AF) regions of the hybrid reactor on bio-degradation of organic compounds using VFA as an operational parameter. Acetic, propionic, butyric, and valeric acid concentrations of samples taken from the reactor effluent, fixed bed region and the upper part of the sludge bed region were analysed. VFA formation was monitored at two phases. In phase-I, 10 kg COD m −3 per day organic loading rate (OLR) ( C o=10,000 mg COD l −1 and θ H=1 day) and in phase-II 7.6 kg COD m −3 per day OLR ( C o=15,000 mg COD l −1 and θ H=2 days) was applied. The average acetic acid concentrations of the upper end of the reactor and sludge bed region were 150 and 354.9 mg l −1, respectively. These results showed that VFA concentrations increase from the top to the bottom of the reactor, indicating higher methanogenic activity in the upper part and higher acetogenic activity in the bottom of the reactor. pH measurements confirmed this result.

Integrated assessment for anaerobic biodegradability of organic compounds using the analytical hierarchy process

Anaerobic biodegradability of organic compounds can be assessed from the changes in organic compounds, the end products, and the activity of microorganisms. In this study, all three of these variables were considered to integrate assessment of the anaerobic biodegradability of organic compounds. The analytical hierarchy process (AHP) was introduced to integrate the assessment. Real values between 0 and 10 were determined in the pairwise comparison matrix according to the values of assessment indices of the three variables. A new adjustment method, which can obtain minimum adjustment of the values in matrix, was proposed to reach the acceptable consistency of the matrix. Finally, the anaerobic biodegradability of 14 organic compounds was assessed using AHP.

A laboratory batch reactor test for assessing nonspeciated volatile organic compound biodegradation in activated sludge.

The relative rates of biodegradation and stripping and volatilization of nonspeciated volatile organic compounds (VOCs) in wastewater treated with aerobic activated-sludge processes can be quantified using a newly developed procedure. This method was adapted from the original aerated draft tube reactor test that was developed to measure biodegradation rate constants for specific volatile pollutants of interest. The original batch test has been modified to include solid-phase microextraction (SPME) fibers for sampling in the gas phase. The experimental procedure using SPME fibers does not require specific identification and quantitation of individual pollutants and can be used to evaluate wastewater with multiple VOCs. To illustrate use of this procedure, laboratory experiments were conducted using biomass and wastewater or effluent from three activated-sludge treatment systems. Each experiment consisted of two trials: a stripping-only trial without biomass and a stripping plus biodegradation trial using biomass from the activated-sludge unit of interest. Data from the two trials were used to quantify the rates of biodegradation by difference. The activated-sludge systems tested were a laboratory diffused-air reactor treating refinery wastewater, a full-scale surface aerated reactor treating a petrochemical wastewater, and a full-scale diffused-air reactor treating a variety of industrial effluents. The biodegradation rate constant data from each laboratory batch experiment were used in model calculations to quantify the fraction emitted (fe) and the fraction biodegraded (fbio) for each system. The fe values ranged from a maximum of 0.01 to a maximum of 0.32, whereas fbio values ranged from a minimum of 0.40 to a minimum 0.95. Two of these systems had been previously tested using a more complicated experimental approach, and the current results were in good agreement with previous results. These results indicate that biodegradation rate constant data from this laboratory method can be successfully used to predict the fate of VOCs in field-scale treatment units, and thus could potentially be used for demonstration of compliance with wastewater VOC emission regulations.