Corrosion Rate Evaluation and Prediction for Piles Based on Long-Term Field Performance

A study to evaluate corrosion rates was conducted using pile foundations abandoned during the reconstruction of I-15 through Salt Lake Valley, Utah. Corrosion rates were measured for 20 piles extracted from five sites after service lives of 34–38 years. Measurements were made of soil index properties, resistivity, pH, cation/anion concentrations, and water table elevation. The critical zone for corrosion was typically located within the groundwater fluctuation zone; but correlations with soil properties were generally poor. Despite low resistivity, average corrosion rates for pile caps in native soil were typically between 2 and 9?μm/year with a maximum of 19?μm/year and did not pose any structural integrity problems. Nevertheless, for abutment piles where chloride concentration was very high, the average pile corrosion rate increased to 13?μm/year within the embankment and the maximum corrosion rate was 48?μm/year in the underlying native soil. Based on data from this and previous studies, equations were developed to predict maximum corrosion loss for piles in nonaggressive soil as a function of time.     

Microbiological quality and the inability of proteolytic Clostridium botulinum to produce toxin in film-packaged fresh-cut cabbage and lettuce

The production of toxin by a 10-strain mixture of proteolytic Clostridium botulinum in fresh produce packaged in polyethylene films having high (7,000 cc/m2/24 h; HOTR) and low (3,000 cc/m2/24 h; LOTR) relative oxygen permeability was determined. Shredded cabbage and lettuce inoculated with approximately 10(2) spores/g were placed in bags composed of the two films (1.4 kg/bag), and the bags were then vacuum sealed. Produce was stored at 4, 13, and 21 degrees C for up to 21 (cabbage) or 28 (lettuce) days and analyzed periodically. At each sampling time, the gas composition within the bags, pH of the produce, and microbial populations (total aerobic and anaerobic microorganisms, lactic acid bacteria, psychrotrophic bacteria, and yeasts and molds) were determined. In addition, the presence of botulinal toxin was determined using the standard U.S. Food and Drug Administration mouse bioassay protocol. Bags made of HOTR film prolonged sensory quality of cabbage and lettuce, especially at 13 and 4 degrees C. Packaging material had an effect on the growth of various groups of microorganisms; however, there was not a general trend. For example, lettuce packaged in HOTR bags had higher aerobic microbial populations than that packed in LOTR, but no significant difference (P < or = 0.05) was observed with cabbage. Growth of psychrotrophic bacteria was greater in vegetables packaged in HOTR film while growth of yeasts and molds was not affected by either packaging film. Most differences in microbial populations in produce packaged in LOTR and HOTR films were less than 1 log10 CFU/g. Botulinal toxin was not detected in cabbage or lettuce packaged in either film or stored under any test condition.     

Environmental Factors and the Application of Hydrogen Peroxide for the Removal of Toxic Cyanobacteria from Waste Stabilization Ponds

Toxin-producing cyanobacteria constitute a serious threat to human and environmental health. It is thus essential that an effective treatment guarantees the removal of cyanobacteria from wastewater before its inclusion in water recycling or environmental flow. Hydrogen peroxide (H2O2) has been shown to induce cyanobacterial decay in laboratory cultures. However, its application for the removal of cyanobacteria from wastewater treatment ponds under environmental conditions has not been investigated. To examine the effects of environmental factors, field trials were performed at both the mesocosm and full-scale levels. The mesocosm trial was completed under field conditions of incident radiation, with various H2O2 concentrations. A concentration of 1.1×10-4??gH2O2/μg chl-a resulted in a 32% decrease in cyanobacterial concentration after 24?h, and this approximate concentration was then applied to a wastewater treatment pond in the full-scale trial. In the full-scale experiment, intense spatial and temporal monitoring of phytoplankton concentrations and temperature throughout the pond was performed. Cyanobacterial biomass was reduced by 57% and total phytoplankton biomass by 70% within 48?h of H2O2 addition. Mixing and radiation were shown to control the depth reached by H2O2 following addition to the ponds. The synergistic effect of H2O2 addition with environmental factors increased the effectiveness of cyanobacterial removal compared with laboratory experiments. The concentration of H2O2 required for the removal of cyanobacteria under field conditions may be decreased from laboratory studies by an order of magnitude.     

Effect of Dynamic Loading on Biological Nutrient Removal in a Pilot-Scale Liquid-Solid Circulating Fluidized Bed Bioreactor

A pilot-scale liquid-solid circulating fluidized bed (LSCFB) bioreactor was employed for biological nutrient removal from municipal wastewater at the Adelaide Pollution Control Plant, London, Ontario, Canada. Lava rock particles of 600?μm were used as a biomass carrier media. The system generated effluent characterized by <1.0?mg NH4–N/L, <6.0?mg NO3–N/L, <1.0?mg PO4–P/L, <10?mg TN/L, and <10?mg SBOD/L at an influent flow of 5?m3/d, without adding any chemicals for phosphorus removal and secondary clarification for suspended solids removal. The impact of the dynamic loading on the LSCFB effluent quality and its nutrient removal efficiencies were monitored by simulating wet weather condition at a maximum peaking factor of 3 for 4 h. The achievability of effluent characteristics of 1.1 mg NH4–N/L, 4.6 mg NO3–N/L, 37 mg COD/L, and 0.5 mg PO4–P/L after 24 h of the dynamic loading emphasize the favorable response of the LSCFB to the dynamic loadings and the sustainability of performance without loss of nutrient removal capacity.     

Biomass of Sediment Bacteria by Sedimentation Field-Flow Fractionation

Accurate estimation of sediment microbial biomass is needed for studies in microbial ecology. The most common techniques currently used to estimate biomass in sediments are not only prone to considerable uncertainty, but are also time-consuming and labor-intensive. In the present study, a relatively new separation and sizing technique, sedimentation field flow fractionation (SdFFF), previously developed for biomass determination of bacteria in cell cultures and natural waters, was used to determine sediment bacterial biomass. SdFFF together with epifluorescence microscopy for cell counting in separated fractions was used for estimating the biomass in sediment samples from a wetland and a river site. Cell counting was required as yellow autofluorescing particles interfered with the on-line detector signal from the fluorescent tagged bacteria (blue) making this simple method of monitoring cell numbers impossible. Calibration curves were obtained that can be used for calculation of sediment bacterial biomass from cell count data for the two sites under study. This demonstrates that for specific systems the less tedious total counts method can be used to generate quantitative biomass estimates using SdFFF to provide accurate calibration for the conversion of counts to biomass. This approach overcomes the serious problems associated with conventional methods that often assume a constant biomass to cell counts or cell volume ratio between collection sites. The SdFFF method was applied to monitor cell growth in sediment samples after addition of phosphate and several types of carbon sources. On incubation for eight days, carbon-amended sediments showed higher bacterial biomass and contained more aggregated colonies, which needed to be dislodged by more vigorous treatment than those treated with phosphate alone.     

Rapid, automated separation of specific bacteria from lake water and sewage by flow cytometry and cell sorting

The use of fluorescence-activated flow cytometric cell sorting to obtain highly enriched populations of viable target bacteria was investigated. Preliminary studies employed mixtures of Staphylococcus aureus and Escherichia coli. Cells of S. aureus, when mixed in different proportions with E. coli, could be selectively recovered at a purity in excess of 90%. This was possible even when S. aureus composed only approximately 0.4% of the total cells. Cell sorting was also tested for the ability to recover E. coli from natural lake water populations and sewage. The environmental samples were challenged with fluorescently labelled antibodies specific for E. coli prior to cell sorting. Final sample purities of greater than 70% were routinely achieved, as determined by CFU. Populations of E. coli released into environmental samples were recovered at greater than 90% purity. The use of flow cytometry and cell sorting to detect and recover viable target bacteria present at levels of less than 1% within an indigenous microflora was also demonstrated.     

Spatial-Dynamic Modeling of Algal Biomass in Lake Erie: Relative Impacts of Dreissenid Mussels and Nutrient Loads

Over the past several decades, reductions in phytoplankton stocks and increased water clarity in Lake Erie have resulted from phosphorus load abatement and the introduction of zebra (Dreissena polymorpha) and quagga mussels (D. bugensis). The relative impacts of these developments and their implications for lake management have remained difficult to delineate. To address this issue, we numerically model the complex biophysical interactions occurring in Lake Erie using a two-dimensional hydrodynamic and water quality model that is extended to include dreissenid mussel and zooplankton algorithms. The model reasonably simulates longitudinal trends in water quality as well as the dynamics of central basin hypoxia. Phosphorus is the limiting nutrient through the euphotic zone and its control decreases the algal growth rate and biomass ( ～ 55–60%). Filter feeding by dreissenid mussels also decreases algal biomass ( ～ 25–30%), simultaneously stimulating increased net algae growth through enhanced algal consumption and subsequent phosphorus recycling. Effective recycling implies that algae stocks are ultimately regulated by external phosphorus loads. Returning phosphorus loads to pre-abatement 1960s levels, in the presence of dreissenid mussels, results in a western basin algae concentration of ～ 0.7?mg?dry?weight?L?1 with a potential for nuisance algae growth.     

High-Rate Biodegradation of Phenol by Aerobically Grown Microbial Granules

This study demonstrates that aerobic granules can be developed to achieve high phenol loading rates in a sequencing batch reactor. The reactor was started at a loading rate of 1.5 kg?phenol?m?3?d?1 with phenol-enriched activated sludge as inoculum. Granules first appeared on Day 9 after startup and quickly grew to become the dominant biomass in the reactor. The phenol loading was then adjusted stepwise to a final value of 2.5 kg?phenol?m?3?d?1. At this high loading, phenol was completely degraded and high biomass concentration was maintained in the reactor. The biomass continued to possess a good settling ability, with a sludge volume index of 60.5 mL?g?SS?1 (SS stands for suspended solids). Granules remained stable, without significant deterioration in granule structure and physiology, even at the maximum phenol loading rate tested. The applied selection pressure enabled the micro-organisms to aggregate into granules, and the compact structure of the aerobic granules served both to retain biomass and protect the microbial cells against the phenol toxicity. High specific phenol degradation rates exceeding 1 g?phenol?g?VSS?1?d?1 (VSS stands for volatile suspended solids) were sustained up to phenol concentrations of 500 mg?l?1, and significant rates continued to be achieved up to a phenol concentration of 1,900 mg?L?1. The phenol-degrading aerobic granules can be exploited to design compact high-rate aerobic granulation systems for the treatment of industrial wastewaters containing high concentrations of phenol and other inhibitory chemicals.     

Study on Pb and PAHs Emission Levels of Heavy Metals- and PAHs-Contaminated Soil during Thermal Treatment Process

The objective of this study was to use thermal treatment to treat soil contaminated with heavy metals and polycyclic aromatic hydrocarbons (PAHs). The emissions of lead (Pb) and PAHs during the thermal treatment process were evaluated. The parameters included pretreatment, temperature, and speed of the rotary kiln. Cadmium (Cd) had a higher mobility in thermally treated contaminated soil slag than other heavy metals because the primary fraction of Cd was the exchangeable fraction (90%). Of the temperatures tested in this study, the highest emission concentration of Pb occurred at 700°C. The Pb emission concentrations in the gas phase and solid phase were 44?μg/N?m3 and 138.35?μg/N?m3, respectively. In PAHs emissions, naphthalene, acenaphthene (Acp), and fluorene were the main species in the gas phase, at different operating temperatures. The concentrations of these species ranged from 615.5 to 2,002.3?μg/N?m3. Acp and chrysene were the main species in the solid phase at different temperatures, and the concentrations of these species ranged from 25.5 to 113?μg/N?m3.     

Enhanced Biological Phosphorus Removal Performance and Microbial Population Changes at High Organic Loading Rates

A laboratory-scale sequencing batch reactor was operated and the dynamics of Rhodocyclus-related phosphorus-accumulating organisms (PAOs) population was monitored. After the system reached a steady state and showed a stable enhanced biological phosphorus removal status, the organic loading rate was increased from 160 to 1,020?g?COD?m?3?cycle?1 in five steps. When the P storage capacity reached maximum at 330?g?COD?m?3?cycle?1, the system lost the stability and the effluent phosphorus concentration fluctuated. As the organic loading rate increased from 160 to 1,020?g?COD?m?3?cycle?1, the PAO population decreased from 83.8±4.9 to 32.2±16.2% and internal polyphosphate content decreased from 0.20 to 0.03?mg?P?mg?VSS?1. Phosphate-accumulating metabolism was weakened as the organic loading rate increased and PAO population decreased concomitantly, whereas glycogen-accumulating metabolism increased at high organic loading rates as supported by the increased intracellular glycogen content and production of a higher fraction of intracellular poly-β-hydroxyl valerate.     

Direct Numerical Simulation of Microparticle Motion in Channel Flow with Thermophoresis

The motion of microparticles in a vertical flow channel driven by drag and thermophoretic forces was simulated using the direct numerical simulation method with the particles tracked using the Lagrangian method. The particle motions were analyzed for five sizes of particles (dp = 1, 2.5, 10, 20, and 100?μm) at three temperature differences (Δt = 0, 130, and 180°C). The results showed that the effect of thermophoresis on the deposition near the wall decreases with increasing particle diameter and can be neglected for particles with dp = 100?μm. Since the deposition rates of inhalable particles (PM10) increase dramatically as the thermophoresis force increases, especially for particles with dp = 1?μm, thermophoresis is an effective method for collecting inhalable particles.     

Oxidation kinetics of vanadium-bearing LD converter slag by mechanical activation

A thermogravimetric investigation was performed to evaluate the kinetic and thermodynamic parameters and the influence of mechanical activation on oxidation of vanadium-bearing LD (Linz–Donawitz) converter slag. Results indicate that the particle size of d_0.5 significantly decreased from 29?μm to 0.266?μm after activation, and the specific surface area based on the BET model increased from 1.324?m²/g to 3.289?mm²/g. Thermogravimetric investigations were separately performed at 650, 700, 750, 800, 850, 900, 950 and 1000°C. Two distinct stages in the oxidation process were identified. The first stage was controlled by nucleation and growth and the second stage was controlled by 3D diffusion. However, the first stage relatively contributed more to the entire process than the second stage. Kinetic study also reveals that mechanical activation exhibited a significant effect on the oxidation of LD converter slag. Mechanical activation significantly reduced the roasting temperature and shortened the roasting time. The corresponding apparent activation energy E_a and frequency factor A changed from 13.01?kJ/mol to 6.59?kJ/mol and 0.247?min^?1 to 0.141?min^?1 for unmilled and milled slags, respectively.     

Comparative Study between a Hybrid System and a Biofilm System for the Treatment of Ammonia and Organic Matter in Wastewaters

The efficiency of two similar gas-lift bioreactors, a biofilm reactor and a hybrid circulating floating bed reactor (CFBR), were studied and compared. In the biofilm CFBR the biomass grew preferably adhered on a plastic granular support, whereas in the hybrid CFBR both suspended biomass and biofilms were allowed to grow in the reactor. COD/NH4+ ratio (COD=chemical oxygen demand) was manipulated between 0.0 and 8.0?g/g, maintaining the ammonia influent concentration around 50?mg N–NH4+/L, the ammonia loading rate at 0.9?kg N–NH4+/m3?day and the hydraulic retention time at 1.36?h. At low COD/NH4+ ratio (0 and 0.5?g/g) both systems behaved similarly, achieving ammonia removal percentages higher than 95%. In the biofilm CFBR a reduction of the nitrification percentage from 95 to 20% was observed when a COD/N–NH4+ ratio up to 8?g/g was applied in the influent. However, at the same operational conditions, the nitrification process in the hybrid CFBR was slightly affected. In the hybrid-CFBR reactor heterotrophs growing in suspension consumed the COD source faster than those growing in biofilms as was monitored. The growth of heterotrophic microorganism in suspension had a beneficial effect for the nitrifying population growing in the biofilm of the hybrid CFBR. Nitrifying activity of the biofilm was not limited by the presence of heterotrophs consuming dissolved oxygen, displacing the nitrifying bacteria or creating mass transfer resistance as was observed in the biofilm CFBR.     

Particulate Matter from Stone Crushing Industry: Size Distribution and Health Effects

A cluster of 50 stone crushing units located at Pammal, in suburban Chennai, the capital of Tamil Nadu State, India, is a source of high levels of dust generation in the vicinity of the crushers and in the communities surrounding them. Ambient air quality network consisting of 26 sampling locations were operated to continuously monitor the total and respirable particulate matter concentrations (TSP and PM10). The daily average ambient concentrations of TSP and PM10 varied from 342 to 2,470 and 90 to 1,200?μg/m3, respectively, near the source, while the average concentrations varied from 86 to 257 and 39 to 138?μg/m3 in ambient air. The average PM2.5 concentration varied from 41 to 388?μg/m3 at the source, whereas the concentration varied from 17 to 48?μg/m3 in ambient air. Personal samplers were also employed to quantify the TSP and RPM in the work environment and they varied from 22.5 to 80.5 and 13.5 to 53.7?mg/m3, respectively. Both ambient concentrations and occupational exposure levels exceeded the Indian National Standards at most of the locations. Pulmonary function tests performed on workers showed that the average values of pulmonary function in these workers are significantly lower than the average values reported for normal South Indian healthy males.     

Ceramic Filter for Small System Drinking Water Treatment: Evaluation of Membrane Pore Size and Importance of Integrity Monitoring

Ceramic filtration has recently been identified as a promising technology for drinking water treatment in households and small communities. This paper summarizes the results of a pilot-scale study conducted at the U.S. Environmental Protection Agency’s (EPA) Test & Evaluation (T&E) Facility in Cincinnati on two ceramic filtration cartridges with pore sizes of 0.05 and 0.01?μm to evaluate their ability to remove turbidity and microbiological contaminants such as bacteria [Bacillus subtilis ( ≈ 1.0?μm) and Escherichia coli ( ≈ 1.4?μm)], Cryptosporidium oocysts (4–6?μm), polystyrene latex (PSL) beads (2.85?μm) (a surrogate for Cryptosporidium), and MS2 bacteriophage ( ≈ 0.02?μm) (a surrogate for enteric viruses). The results demonstrated that the relatively tighter 0.01-μm cartridge performed better than the 0.05-μm cartridge in removing all the biological contaminants and surrogates. For turbidity removal, the 0.01-μm cartridge performed slightly better than the 0.05-μm cartridge; however, the permeate rate in the 0.01-μm cartridge reduced rapidly at higher feed water turbidity levels indicating that a tighter membrane should only be used with adequate pretreatment or at a low feed water turbidity to prolong membrane life. Microbiological monitoring was identified as a more sensitive indirect integrity monitoring method than turbidity and particle count monitoring to ensure effective treatment of water by ceramic filtration. Both PSL beads and B. subtilis showed potential as effective surrogates for Cryptosporidium, with B. subtilis showing higher degree of conservatism. Any opinions expressed in this article are those of the writer(s) and do not necessarily reflect the official positions and policies of the EPA. Any mention of products or trade names does not constitute recommendation for use by EPA. This document has been reviewed in accordance with EPA’s peer and administrative review policies and approved for publication.     

Rapid assessment of antibiotic effects on Escherichia coli by bis-(1,3-dibutylbarbituric acid) trimethine oxonol and flow cytometry

The effects of selected antibiotics on Escherichia coli were studied by flow cytometry with the fluorescent anionic membrane potential probe bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)]. The actions of azithromycin, cefuroxime, and ciprofloxacin at five times the MIC on E. coli were compared by the traditional CFU assay and flow cytometry. Changes in viable counts of bacteria determined with DiBAC4(3) and by flow cytometry following treatment with the antibiotics showed trends similar to those found by the CFU assays. However, viable counts determined by flow cytometry following antibiotic treatment were 1 to 2 logs higher than those determined by the corresponding CFU assays. All the results obtained by flow cytometry were provided within 10 min after sampling, whereas the conventional CFU assay results took at least 18 h. The results indicated that flow cytometry is a sensitive analytical technique that can rapidly monitor the physiological changes of individual microorganisms following antibiotic action and can provide information on the mode of action of a drug. The membrane potential probe DiBAC4(3) provides a robust flow cytometric indicator for bacterial cell viability.     

钼蓝分光光度法联合测定铁矿石中磷和二氧化硅

以往铁矿石中磷和二氧化硅含量的测定需要分别采用钼蓝分光光度法。在使用磷钼蓝分光光度法时,常会因钒、砷等的干扰使得磷测定结果不准确,需要将样品再处理后才能测定。实验采用石墨垫底铁坩埚,碳酸钠和硼酸混合熔剂高温熔融铁矿石,使铁矿石样品分解彻底,再分别采用铋磷钼蓝和硅钼蓝分光光度法测定磷和二氧化硅含量,从而实现了采用钼蓝分光光度法联合测定铁矿石中磷和二氧化硅。干扰试验表明,在高温熔融时,石墨可将钒(V)还原为钒(III),使样品中钒不干扰磷的测定;显色液中加入15mg硫代硫酸钠溶液可将砷(V)还原为砷(III),继而消除砷对磷测定的干扰。磷的质量浓度在0~3μg/mL范围内遵守比尔定律,校准曲线的线性相关系数为0.9999,表观摩尔吸光系数为2.242×10⁴ L·mol^-1·cm^-1;二氧化硅的质量浓度在0~5μg/mL范围内遵守比尔定律,校准曲线的线性相关系数为0.9995,表观摩尔吸光系数为9.342×10³ L·mol^-1·cm^-1。方法中磷和二氧化硅的检出限分别为0.0026μg/mL和0.0081μg/mL。按照实验方法测定6个铁矿石标准样品中磷和二氧化硅,磷测定结果的相对标准偏差(n=8)小于5%,相对误差小于2%;二氧化硅测定结果的相对标准偏差(n=8)小于2%,相对误差小于1.5%。按照实验方法测定5个铁矿石样品中磷和二氧化硅,磷测定结果的相对标准偏差(RSD,n=8)小于7%,二氧化硅测定结果的相对标准偏差(n=8)小于1%;磷和二氧化硅的测定值均与电感耦合等离子体原子发射光谱法的测定值相一致。     

Performance Assessment of a New Type of Membrane Bioreactor under Steady State and Transient Operating Conditions

Methyl-t-butyl ether (MTBE) is an additive to gasoline that serves as an oxygenate to increase the octane rating and improve combustion efficiency. Assessment of MTBE biodegradation under aerobic conditions was performed in lab-scale biomass concentrator reactors (BCRs). These reactors were bench-scale microcosms that retain and concentrate biomass thereby enabling biodegradation to sub-μg/L level. The BCRs were run under low hydraulic retention times with a synthetically prepared feed containing 500??μg/L of several oxygenates, MTBE, diisopropyl ether (DIPE), ethyl-t-butyl ether (ETBE), t-amyl methyl ether (TAME), t-amyl alcohol (TAA), and the primary gasoline constituents benzene, toluene, ethyl benzene, and p-xylene (BTEX). The BCRs were effective in the removal of the aforementioned contaminants to concentrations lower than the targeted 5??μg/L, which is below the U.S. Environmental Protection Agency (EPA) taste and odor threshold of 20–40??μg/L. Reactor performance was also evaluated under shock loading and intermittent feeding (starvation tests) of the contaminants of concern to evaluate the reactor’s robustness in recovering from such stresses. The BCRs were found to be highly resilient to fluctuations in substrate and flow conditions.     

Phosphorus Treatment Capability of Marshland Upwelling System under High Background Salinity Conditions

The marshland upwelling system (MUS) is an alternative onsite wastewater treatment system developed for coastal communities. The phosphorus treatment efficiency of the MUS operated under high background salinity conditions ( ～ 32?ppt) was examined over the course of a one-year field study. Five individual studies were investigated by intermittently injecting wastewater at a depth of 3.8?m using flow rates/injection frequency regimes of 1.9?L/min (30?min/3?h), 5.5?L/min (30?min/3?h), 2.8?L/min (30?min/3?h), and 2.8?L/min (15?min/h). There were two studies conducted within the 2.8?L/min (30?min/3?h) flow regime: (1) with normal influent and (2) with high strength synthetic wastewater. Over the course of the study, no signs of phosphorus saturation were observed. The overall system efficiency for the entire study was estimated to be >98%. Removal rate coefficients ranged from 0.73–1.25?m?1 and 0.66–1.08?m?1 for total phosphorus and orthophosphate, respectively. Upon completion of the final 2.8?L/min (15?min/h) study, it was determined that a travel distance of only 9.4?m would be needed to reduce influent concentrations below 0.1?mg?P/L.     

Treatment of MTBE-Contaminated Water in Fluidized Bed Bioreactor

Methyl tertiary-butyl ether (MTBE) biodegradation was evaluated in a laboratory-scale granular activated carbon (GAC)-based fluidized bed bioreactor system. The reactor was operated in seven distinct phases during which the MTBE loading rate, hydraulic retention time, cocontaminant loading [butyl, toluene, ethylbenzene, and xylene (BTEX) and tertiary-butyl alcohol (TBA)] and temperature were varied. The reactor was able to treat MTBE to less than 20 ug/L at 25°C and total organic carbon (TOC) loading rates between 0.01 and 1.1 kg/m3 of expanded GAC bed per day (kg/m3?day). Net biomass yield in the reactor under high loading conditions was approximately 0.55 g of total suspended solids (TSS) per gram of TOC consumed. This high yield under the higher loading rates necessitated that biomass be removed from the reactor to control bed expansion. At a loading rate of 1.5 kg/m3?day, MTBE effluents exceeded 20 ug/L. Reactor performance decreased as the reactor temperature was reduced from 25 to 15°C, but even at the lower temperatures MTBE removal efficiency exceeded 99%. Methyl tertiary-butyl ether treatment efficiency was not affected by the addition of TBA or BTEX under the conditions evaluated. Results of this study demonstrate that fluid bed bioreactors inoculated with an appropriate microbial culture can efficiently treat MTBE-contaminated water.