Range Of Influent Concentrations Research Articles

Improvement of phosphorus removal in bioretention cells using real-time control

ABSTRACT Retrofitting urban watersheds with wireless sensing and control technologies will enable the next generation of autonomous water systems. While many studies have highlighted the benefits of real-time controlled gray infrastructure, few have evaluated real-time controlled green infrastructure. Motivated by a controlled bioretention site where phosphorus is a major runoff pollutant, phosphorus removal was simulated over a range of influent concentrations and storm conditions for three scenarios: a passive, uncontrolled bioretention cell (baseline), a real-time controlled cell (autonomous upgrade), and a cell with soil amendments (passive upgrade). Results suggest the autonomous upgrade matched the pollutant treatment performance of the baseline scenario in half the spatial footprint. The autonomous upgrade also matched the performance of the passive upgrade; suggesting real-time control may provide a ‘digital’ alternative to existing, passive upgrades. These findings may help site- and cost-constrained stormwater managers meet their water quality goals.

Predicting removal kinetics of biochemical oxygen demand (BOD) and nutrients in a pilot scale fed-batch algal wastewater treatment system

Our previous reports have presented single-step treatment of primary-settled urban wastewater by a mixotrophic alga, Galdieria sulphuraria. Here, we present an approach to predict the operational cycle time, t*, required to meet the discharge standards for ammoniacal-nitrogen (NH3-N), phosphate (PO4) and biochemical oxygen demand (BOD) in fed-batch mode, under varying influent concentrations. First order removal rates of NH3-N, PO4 and BOD, determined using data from 10 fed-batch cycles in a pilot scale system (700 L), were used to predict their temporal fate and t* in 30 other cycles. Predicted concentrations of NH3-N, PO4, and BOD and t* over a wide range of influent concentrations agreed well with the measured ones, with root mean square errors, respectively, of 2.06 mg/L, 0.23 mg/L, 2.88 mg/L and 0.30 days. The coefficient of determination between the measured and the predicted values were as follows: for NH3-N: r2 = 0.82, n = 90; for PO4: r2 = 0.87, n = 90; for BOD: r2 = 0.70, n = 30; and for t*: r2 = 0.61, n = 30. The validity of the model in predicting temporal concentration profiles of NH3-N, PO4 and BOD reflected by Janus quotient (respectively of 0.85, 0.87 and 0.61) is comparable to or better than those reported in the literature. Sensitivity analysis procedures identified the influent concentration of PO4 as the most sensitive parameter in predicting t*.

Advancing performance evaluation standards for household water treatment technologies.

Diarrheal illnesses and fatalities continue to be major issues in many regions throughout the world. Household water treatment (HWT) technologies (including both point-of-use (POU) and point-of-entry (POE) treatment solutions) have been shown as able to deliver safe water in many low-income communities. However, as shown herein, there are important inconsistencies in protocols employed for validating performance of HWTs. The WHO does not stipulate influent concentration as a parameter that could influence removal efficacy, nor does it indicate an influent concentration range that should be used during technology evaluations. A correlation between influent concentration and removal is evidenced herein (R2 = 0.88) with higher influent concentrations resulting in higher log-removal values (LRVs). The absence of a recommended standard influent concentration of bacteria (as well as for viruses and protozoa) could have negative consequences in intervention efforts. Recommendations are provided that regulatory bodies should specify an influent concentration range for testing and verification of HWT technologies.

Analysis of a Chemostat Model with Variable Yield Coefficient and Substrate Inhibition: Contois Growth Kinetics

We analyze the steady-state operation of a generalized reactor model that encompasses a continuous flow bioreactor and an idealized continuous flow membrane reactor as limiting cases. The biochemical reaction kinetics is governed by a Contois growth model subject to noncompetitive substrate inhibition with a variable substrate yield coefficient. The steady-state performance of the reactor is predicted and stability of the steady-state solutions as a function of dimensionless residence time reported. Our results identified two cases of practical interest. The first feature corresponds to the case where solutions to both no-washout and washout conditions are bistable. The second feature identifies the parameter region in which periodic solutions can occur when the yield coefficient is not constant. Both these features are often undesirable in practical applications and must be avoided. Scaling of the model equations reveals that both the second-bifurcation parameters are functions of the influent concentration. Our results predict how the reactor behavior varies as a function of influent concentration and identify the range of influent concentrations where the reactor displays neither periodic nor bistable behavior.

A hydrologic tracer study in a small, natural wetland in the humid tropics of Costa Rica

Growing populations and food demand in the tropics are leading to increased environmental pressures on wetland ecosystems, including a greater reliance on natural wetlands for water quality improvement. Effective assessment of wetland treatment potential requires an improved understanding of the hydraulic and biogeochemical factors that govern contaminant behavior, however detailed studies of flow through natural, tropical wetlands are scarce. We performed a tracer study using a conservative salt (potassium bromide) to examine the hydraulic behavior of a small, natural wetland in the Costa Rican humid tropics and modeled observed breakthrough curves using the 1-D advection–dispersion equation. Velocities in the wetland were extremely slow, from less than 4 m day−1 to a maximum of ~30 m day−1, and were distributed across several flowpaths, illustrating a spatial heterogeneity of flow and velocities. Modeled dispersion coefficients were also low (33 ± 33 m2 day−1). Estimated residence times suggested high potential pollutant removal capacity over a range of influent concentrations, reinforcing the environmental services provided by this and other small tropical wetlands. The study also highlighted how small variations in wetland topography and vegetation yield strong differences in transport patterns that affect transport and mixing in densely vegetated, heterogeneous wetland systems. Empirical data on the hydraulics, and resulting ecosystem functions, of small, distributed wetlands may provide support for improved conservation and management of these important ecosystems.

The Monod and a biphasic biodegradation kinetics of diesel hydrocarbons by a biofilm of Pseudomonas and the potential electromotive force involved

AbstractBACKGROUNDTwo kinetic models for diesel degradation in a continuous‐flow reactor at a retention time of 1.5 h were compared. One model included the Monod equation and the other, a biphasic model, did not involve Monod parameters. The experiment included two Pseudomonas species. A thermodynamic study on the nitrate‐reducing degradation of diesel was performed in addition to a BOD5 /COD ratio to evaluate the biodegradability of both the diesel components and their residual concentrations.RESULTSThe Monod model revealed that both μmax,h and for the C10–C18 chains were 2.5‐fold and 11‐fold, respectively, lower than those of chains C20–C22. The biphasic model failed to detect the influent concentration range at which the biofilm slowed down processing the substrates. The shifts of the influent‐to‐effluent BOD5/COD ratios from 0.67 to 0.80 and from 0.80 to 0.95, for the lowest and highest substrate concentrations, respectively, confirmed that residuals in the effluent can be degraded. Stoichiometric calculations for C10–C22 revealed theoretical spontaneous release of Gibbs free energies from –6.89 to –70.27 kJ, and electromotive forces from 4.4 to 45.51 mV for both the lowest and highest diesel concentrations, respectively.CONCLUSIONThe influent diesel concentration interval of 1008–1344 mg L−1 was the range over which the maximum utilization rates of chains C10–C22 decreased from 1.12 to 0.57 vss−1 due to the inhibitory action of chains C10–C18 (P<0.05). Following the degradation of diesel, the organic residuals left in the effluent can be easily assimilated. The nitrate‐reducing degradation was able to produce an electromotive force spontaneously. © 2014 Society of Chemical Industry

EFFECT OF COD LOADING RATE ON AN UPFLOW ANAEROBIC SLUDGE BLANKET REACTOR DURING ANAEROBIC DIGESTION OF PALM OIL MILL EFFLUENT WITH BUTYRATE / SUVARTOJAMO CHDS POVEIKIS PALMIŲ ALIEJAUS GAMYBINIŲ NUOTEKŲ SU BUTIRATU ANAEROBINIO PŪDYMO PLOKŠTELINIAME REAKTORIUJE METU

Palm oil Mill Effluent (POME) with concentrated butyrate was treated in a 4.5 l upflow anaerobic sludge blanket reactor (UASBR), run over a range of influent concentrations (16.5–46.0 g-COD l−1), chemical oxygen demand (COD) loading rates (1.5–11.5 g-CODl−1d−1) and 11–4 days hydraulic retention time (HRT) at 37 °C by maintaining pH between 6.5–7.5. The process consistently removed 97–99% of COD at loading rates up to 1.5–4.8 g-COD l−1d−1 by varying HRT (11–7.2 days). Butyrate is an important intermediate in the anaerobic degradation of organic matter. In sulphate-depleted environment, butyrate in POME (BOD/COD ratio of 0.5) is β-oxidised to acetate and hydrogen, by obligate proton reducers in syntrophic association with hydrogen utilizing methanogens. The conversion of acetate to methane appeared to be rate limiting step. Maximum biogas (20.17 ll−1d−1) and methane production (16.2 ll−1d−1) were obtained at COD loading rate of 4.80 gl−1d−1and HRT of 7.2 days. The biogas and methane production were higher in the presence of butyrate compared to control. The methane content of the biogas was in the range of 70–80% throughout the study while in control it was 60–65%. Finding of this study clearly indicates the successful treatment of POME with butyrate in UASBR. Santrauka Palmių aliejaus gamybinės nuotekos (POME) su koncentruotu butiratu buvo apdorotos 4,5 l talpos aukštyn tekančio aerobinio dumblo plokšteliniame reaktoriuje (UASBR). Nuotekos tekėjo įvairių koncentracijų (16,5–46,0 g – ChDS 1−1), cheminio deguonies suvartojimo (ChDS) normos (1,5–11,5 g – ChDS 1−1d.−1). Hidraulinio sulaikymo trukmė (HRT) nuo 11 iki 4 dienų, kai temperatūra 37 °C, pH palaikant 6,5–7,5. Vykstant procesui nuolat buvo pašalinama 97–99% ChD, kai tiekimo ir pakrovimo sparta 1,5–4,8 g – ChDS 1−1d.−1 kintant HRT(11–7,2 d.). Butiratas yra svarbus tarpininkas organinių medžiagų anaerobinio skilimo procese. Sulfatas iš aplinkos, butiratas iš POME (BDS/ChDS santykis 0,5) yra acetato ir vandenilio β oksidatoriai, priverčiantys protonų reducentus sintrofinės sąveikos su vandeniliu metu utilizuoti metanogenus. Acetato virtimas metanu pasirodė esąs greitį ribojantis veiksnys. Daugiausia biodujų (20,17 l 1−1 d.−1) ir metano (16,2 l 1−1 d.−1) susidarė tada, kai suvartojamo ChD tiekimo greitis buvo 4,80 g 1−1d.−1, o HRT – 7,2 dienos. Daugiau biodujų ir metano susidarė dalyvaujant butiratui, palyginti su kontroliniu pavyzdžiu. Biodujose metano kiekis tyrimo metu svyravo 70–80%, o kontroliniame buvo 60–65%. Šis tyrimas aiškiai parodė, kad POME su butiratu UASBreaktoriuje apdorojamas sėkmingai.

Field Application of Farmstead Runoff to Vegetated Filter Strips: Surface and Subsurface Water Quality Assessment

Farmstead runoff poses significant environmental impacts to ground and surface waters. Three vegetated filter strips were assessed for the treatment of dairy farmstead runoff at the soil surface and subsurface at 0.3- or 0. 46-m and 0. 76-m depths for numerous storm events. A medium-sized Michigan dairy was retrofitted with two filter strips on sandy loam soil and a third filter strip was implemented on a small Michigan dairy with sandy soil to collect and treat runoff from feed storage, manure storage, and other impervious farmstead areas. All filter strips were able to eliminate surface runoff via infiltration for all storm events over the duration of the study, eliminating pollutant contributions to surface water. Subsurface effluent was monitored to determine the contributing groundwater concentrations of numerous pollutants including chemical oxygen demand (COD), metals, and nitrates. Subsurface samples have an average reduction of COD concentrations of 20, 11, and 85% for the medium dairy Filter Strip 1 (FS1), medium dairy Filter Strip 2 (FS2), and the small Michigan dairy respectively, resulting in average subsurface concentrations of 355, 3960, and 718 mg L COD. Similar reductions were noted for ammonia and total Kjeldahl nitrogen (TKN) in the subsurface effluent. The small Michigan dairy was able to reduce the pollutant leachate concentrations of COD, TKN, and ammonia over a range of influent concentrations. Increased influent concentrations in the medium Michigan dairy filter strips resulted in an increase in COD, TKN, and ammonia concentrations in the leachate. Manganese was leached from the native soils at all filter strips as evidenced by the increase in manganese concentrations in the leachate. Nitrate concentrations were above standard drinking water limits (10 mg L), averaging subsurface concentrations of 11, 45, and 25 mg L NO-N for FS1, FS2, and the small Michigan dairy, respectively.

NO3−-N removal with sulfur-lime porous ceramic carrier (SLPC) in the packed-bed bioreactors by autosulfurotrophic denitrification

The performance of sulfur-lime porous ceramic carrier (SLPC) in the packed-bed bioreactors (PBBRs) was evaluated. SLPC showed the applicability of energy substrate as well as physical support to the microbial biofilm for the contaminated groundwater treatment. The PBBRs fed with influent concentration range of 20–60mgNO3−-N/L also showed the maximum denitrification efficiency of 99.5% at the loading rate range of 0.22–1.2kgNO3−-N/m3SLPC/d. A comparison with the previous results showed that NO3−-N removal rates of the PBBRs were significantly higher than those of sulfur packed-bed reactors. The nitrous oxide content in the produced gas was found to be less than 1%. Good mass transfer of NO3−-N to the biofilm on sulfur surfaces and absence of clogging problems could be the main reasons for the higher NO3−-N removal rate in the PBBRs. Results presented here also constitute the usability of an innovative SLPC and suggest that the PBBRs with SLPC is suitable for post-denitrification of NO3−-N contaminated groundwater due to unnecessary external energy and alkalinity source.

Removal of antibiotics and non-steroidal anti-inflammatory drugs by extended sludge age biological process

Removal of four antibiotics (sulfamethoxazole, sulfadimethoxine, sulfamethazine and trimethoprim) and four non-steroidal anti-inflammatory drugs (acetaminophen, ibuprofen, ketoprofen and naproxen) using extended sludge age biological process was investigated. The sludge age of the biological system was greater than 200 d. Hydraulic retention time of 12 h was maintained throughout the experiment. The extended sludge age biological process is able to treat pharmaceuticals with good and steady removal efficiencies: 64–93% removal for antibiotics over 1–5 μg L −1 influent concentrations and 94% to complete removal for acetaminophen and ibuprofen with a wide range of influent concentrations 1–100 μg L −1. For ketoprofen and naproxen the removal efficiencies are 79–96% over a range of 1–15 μg L −1 influent concentrations. The removal efficiency decreases with increasing initial concentrations for all target compounds except for ibuprofen. This indicates that the initial influent concentration is an important parameter for the studies of fate of pharmaceuticals. The amount of bio-mass and size of the reactor required to achieve good and steady removal efficiencies for known influent pharmaceutical concentrations are also suggested in this study.

Sorption behavior of Cu(II) ions on insolubilized humic acid under acidic conditions: An application of Scatchard plot analysis in evaluating the pH dependence of specific and nonspecific bindings

Sorption behavior of Cu(II) ions on a humic acid-based solid phase, insolubilized humic acid (IHA), were investigated under continuous column conditions. The quantitative data were derived on the basis of breakthrough curves obtained at different experimental conditions. For the studied experimental conditions, the highest and lowest observable capacities of IHA toward Cu(II) were found as 48.34 and 0.84 μmol g −1, respectively. In order to evaluate the pH dependence of Cu(II) binding on IHA, the effect of influent concentration was investigated at three different pH values (1.0, 2.0 and 3.0), and adsorption isotherms were derived for each acidic condition. The characteristics of Cu(II) bindings were evaluated by using Scatchard plot analysis, and it was observed that under strongly acidic condition, pH 1.0, nonspecific and/or multi-type interactions between Cu(II) and IHA were the prevailing effects causing the Cu(II) sorption. On the other hand, at pH 2.0 and 3.0, the role of specific interactions was more clearly observed, and so at pH(s) 2.0 and 3.0, the binding of Cu(II) on IHA was mainly attributed to specific interactions rather than nonspecific ones. For pH 2.0 and 3.0, the binding types of Cu(II) on IHA were sub-classified according to different affinities observed between Cu(II) and IHA, and thus two main types of specific bindings were proposed for the studied influent concentration range (1.0 × 10 −3 to 1.0 × 10 −1 mol l −1): Type-1, high-affinity/low capacity and Type-2, low-affinity/high capacity bindings. Finally, probable benefit of each specific binding type in separation of Cu(II) from acidic aqueous media has been discussed in detail.

Removal of selected pharmaceuticals, fragrances and endocrine disrupting compounds in a membrane bioreactor and conventional wastewater treatment plants

Eight pharmaceuticals, two polycyclic musk fragrances and nine endocrine disrupting chemicals were analysed in several waste water treatment plants (WWTPs). A membrane bioreactor in pilot scale was operated at different solid retention times (SRTs) and the results obtained are compared to conventional activated sludge plants (CASP) operated at different SRTs. The SRT is an important design parameter and its impact on achievable treatment efficiencies was evaluated. Different behaviours were observed for the different investigated compounds. Some compounds as the antiepileptic drug carbamazepine were not removed in any of the sampled treatment facilities and effluent concentrations in the range of influent concentrations were measured. Other compounds as bisphenol-A, the analgesic ibuprofen or the lipid regulator bezafibrate were nearly completely removed (removal rates >90%). The operation of WWTPs with SRTs suitable for nitrogen removal (SRT>10 days at 10 °C) also increases the removal potential regarding selected micropollutants. No differences in treatment efficiencies were detected between the two treatment techniques. As in conventional WWTP also the removal potential of MBRs depends on the SRT. Ultrafiltration membranes do not allow any additional detention of the investigated substances due to size exclusion. However, MBRs achieve a high SRT within a compact reactor. Nonylphenolpolyehtoxylates were removed in higher extend in very low-loaded conventional WWTPs, due to variations of redox conditions, necessary for the degradation of those compounds.

The solids retention time—a suitable design parameter to evaluate the capacity of wastewater treatment plants to remove micropollutants

Micropollutants as endocrine disrupting compounds (EDC) or pharmaceuticals are of increased interest in water pollution control. Wastewater treatment plant (WWTP) effluents are relevant point sources for residues of these compounds in the aquatic environment. The solids retention time (SRT) is one important parameter for the design of WWTPs, relating to growth rate of microorganisms and to effluent concentrations. If a specific substance is degraded in dependency on the SRT, a critical value for the sludge age can be determined. In WWTPs operating SRTs below this critical value, effluent concentrations in the range of influent concentrations or a distribution according to the adsorption equilibrium have to be expected, whereas in WWTPs operating at SRTs higher than the critical value degradation will occur. Critical SRTs were determined for different micropollutants, indicating that the design criteria based on the sludge age allows an estimation of emissions. Different treatment technologies as conventional activated sludge systems and a membrane bioreactor were considered and no significant differences in the treatment efficiency were detected when operated at comparable SRT. The results of the investigations lead to the conclusion that low effluent concentrations can be achieved in WWTPs operating SRTs higher than 10 days (referred to a temperature of 10 degrees C). This corresponds to the requirements for WWTPs situated in sensitive areas according to the urban wastewater directive of the European Community (91/271/EEC) in moderate climatic zones.

Simultaneous removal of Cr(VI) and phenol in chemostat culture of E. coli ATCC 33456 and P. putida DMP-1

A chemostat coculture consisting of a phenol-degrading organism, P. putida, and a Cr(VI)-reducing strain, E. coli ATCC 33456, was evaluated for its potential to simultaneously remove phenol and Cr(VI). Steady-state operating conditions were obtained with near complete removal of phenol and Cr(VI) under a range of influent concentration of phenol (233–2541 mg/l), influent Cr(VI) (1–10.3 mg/l), and liquid detention time (2–6.7 days).

Simultaneous removal of Cr(VI) and phenol in chemostat culture of e. coli ATCC 33456 and p. putida DMP-1

A chemostat coculture consisting of a phenol-degrading organism, P. putida, and a Cr(VI)-reducing strain, E. coli ATCC 33456, was evaluated for its potential to simultaneously remove phenol and Cr(VI). Steady-state operating conditions were obtained with near complete removal of phenol and Cr(VI) under a range of influent concentration of phenol (233-2541 mg/1), influent Cr(VI) (1-10.3 mg/1), and liquid detention time (2-6.7 days).

Anaerobic digestion of palm oil mill effluent using an up-flow anaerobic sludge blanket reactor

Anaerobic treatment of palm oil mill effluent (POME) was studied using a 16-litre laboratory scale up-flow anaerobic sludge blanket reactor (UASB) run over a range of influent concentrations from 5.1 to 42.5 g Chemical Oxygen Demand (COD) per litre at a constant hydraulic retention time of four days. Methane production, volatile fatty acid conversion, net sludge growth and Chemical Oxygen Demand reduction were monitored. Over 96% Chemical Oxygen Demand was removed at loadings up to 10.6 g COD l −1 day −1. At the highest influent concentration reactor instability was observed. Up to this point the results indicated that the UASB could treat POME more effectively than other systems reviewed.

2,4-D degradation in monoculture biofilm reactors

Two strains of Alcaligenes eutrophus AEO106 were used to inoculate expanded bed biofilm reactors which were exposed to a range of concentrations and loading rates of 2,4-dichlorophenoxyacetic acid (2,4-D herbicide). Two bench-scale reactors were inoculated with bacterial strains containing different plasmids. Plasmid pRO101 expressed the 2,4-D degradative pathway in the presence of inducer (2,4-D or 3-chlorobenzoate), whereas plasmid pRO103 was engineered to allow constitutive expression of the pathway due to the deletion of a regulatory gene. Biofilm growth characteristics, loading rate and 2,4-D conversion efficiency relationships were compared in the two reactors. Actual loading rates tested ranged from 3.6 to 52.3 g 2,4-D per liter expanded bed volume per day (g/ld). The range of influent concentrations tested was between 166 and 728 mg/l (0.017 and 0.078%). Mineral nutrients were supplied in the feed solutions. At loadings up to 15 g/ld, reactors were aerated with filtered air. Pure oxygen was found to be necessary at higher loadings to sustain maximum bacterial activity. Removal of 2,4-D to below detectable concentrations (< 3 mg/l) was demonstrated at all but the highest loadings tested (at least up to 10 g/ld with air and > 25 g/ld with pure oxygen). However, minimum effluent chemical oxygen demand (COD) values were 25 mg/l even at lower loading conditions. Advantages noted with the AEO106 pRO103 (constitutive) biofilm included greater biomass development (up to 3 times higher volatile solids), 50–100% higher specific substrate conversion rates, quicker response to step increases in feed rate and concentration and more consistent effluent quality. Approximately one-third lower effluent COD concentrations, with one-half the standard deviation among individual analyses, were noted with pRO103 compared to pRO101. The genetically engineered biofilm reactor was shown to be a viable experimental treatment technology for one xenobiotic compound in these studies. However, pure culture conditions were not maintained throughout the experiments because of the low-level persistence of a sporadic contaminant bacterial species (identified as Xanthomonas maltophilia), which apparently incorporated plasmids from Alcaligenes eutrophus AEO106.

Anaerobic digestion of cheese whey using an upflow anaerobic sludge blanket reactor: III. Sludge and substrate profiles

Anaerobic treatment of cheese whey using a 17·5 litre upflow anaerobic sludge blanket reactor was investigated in the laboratory over a range of influent concentration from 4·5 to 38·1 g COD litre −1 at a constant hydraulic retention time of 5 days. The results indicated that two sludge distribution regions, a sludge bed and a sludge blanket, as well as two distinct reaction phases, acidogenic and methanogenic, were formed. However, as the substrate loading was increased, the acidogenic region extended into the methanogenic region in the upper portion of the reactor until the whole region was acidogenic, leading to the failure of the reactor.

MANGANESE OXIDATION RELATED TO THE RELEASES FROM RESERVOIRS1

ABSTRACT: Stratified reservoir waters frequently contain objectionable quantities of dissolved manganese. The oxidation and removal of dissolved manganese during transport below Normandy Dam, Tennessee, was shown to be much more rapid than expected from chemical oxidation. Oxidation took place in only a day of travel time rather than months or years. Laboratory studies showed that removal was associated with a slime found on rock surfaces below the dam and led to the development of column technology as a possible method of treating natural waters containing manganese. Hydraulic loadings on the columns in the range of 390–780 m3/hr.ha accomplished a 90 percent removal rate of soluble manganese over an influent concentration range of 2 to 15 mg/l.

Anaerobic digestion of cheese whey using up-flow anaerobic sludge blanket reactor

Anaerobic treatment of cheese whey using a 17·5-litre up-flow anaerobic sludge blanket reactor was investigated in the laboratory. The reactor was studied over a range of influent concentration from 4·5 to 38·1 g chemical oxygen demand per litre at a constant hydraulic retention time of 5 days. The reactor start-up and the sludge acclimatization were discussed. The reactor performance in terms of methane production, volatile fatty acids conversion, sludge net growth and chemical oxygen demand reduction were also presented in this paper. Over 97% chemical oxygen demand reduction was achieved in this experiment. At the influent concentration of 38·1 g chemical oxygen demand per litre, an instability of the reactor was observed. The results indicated that the up-flow anaerobic sludge blanket reactor process could treat cheese whey effectively.