Low Influent Concentration Research Articles

Modeling changes in hydraulic conductivity due to siltation using soil columns from Alshuwaib dam site, United Arab Emirates

Changes in soil hydraulic conductivity (K) as a function of total suspended solids (TSS) concentration in the infiltrating water were studied in the laboratory using the constant-head technique. Soil samples collected from Alshuwaib dam site in the United Arab Emirates were selected for the study. The soil samples were collected from two distinct layers at the dam site; an upper layer which is composed of silt and clay and a lower layer which is mainly composed of sand. Formation of the upper layer is believed to be due to deposition of TSS originally present in the intercepted stormwater or due to dust deposition at the site. Temporal variations in the saturated K of the soil were studied using water with various TSS concentrations. The infiltrating turbid solution was prepared using tap water mixed with soil samples collected from the upper layer. Results show that presence of TSS in the water introduced into the columns caused a drop in K over time. Changes in K follow a sharp drop shortly after injecting the turbid solution and a slower drop at later times. The sharp initial drop was more pronounced for cases with higher injected TSS concentration. For an experimental time of about 80 h, K dropped an order of magnitude for cases with low influent concentration. Changes in K were simulated using a mechanistically based model that assumes formation of new layers with lower K values as a result of particle entrapment below the soil surface followed by particle deposition on the surface. The developed layers model closely predicts variations of K over time, with no observed particle entrapment, except at low TSS concentration. Meanwhile, predicted deposited masses of TSS are in agreement with those determined after the completion of the experiments. Results presented here could also be useful to managers of surface recharge facilities in the country and elsewhere.

Influence of Organic Load on Biohydrogen Production in an AnSBBR Treating Glucose-Based Wastewater.

An anaerobic sequencing batch reactor with immobilized biomass (AnSBBR) was applied to the production of biohydrogen treating a glucose-based wastewater. The influence of the applied volumetric organic load was studied by varying the concentration of influent at 3600 and 5250mg chemical oxygen demand (COD) L(-1) and cycle lengths of 4, 3, and 2h resulting in volumetric organic loads of 10.5 to 31.1g CODL(-1). The results revealed system stability in the production of biohydrogen and substrate consumption. The best performance was an organic removal (COD) of 24% and carbohydrate removal (glucose) of 99%. Volumetric and specific molar productivity were 60.9molH2 m(-3)day(-1) and 5.8molH2 kg SVT(-1)day(-1) (biogas containing 40% H2 and no CH4) at 20.0g CODL(-1)day(-1) (5250mg CODL(-1) and 3h). The yield between produced hydrogen and removed organic matter in terms of carbohydrates was 0.94molH2 Mol GLU(-1) (biogas containing 52% H2 and no CH4) at 10.5g CODL(-1)day(-1) (3600mg CODL(-1) and 4h), corresponding to 23 and 47% of the theoretical values of the acetic and butyric acid metabolic routes, respectively. Metabolites present at significant amounts were ethanol, acetic acid, and butyric acid. The conditions with higher influent concentration and intermediate cycle length, and the condition with lower influent concentration and longer cycle showed the best results in terms of productivity and yield, respectively. This indicates that the best productivity tends to occur at higher organic loads, as this parameter involves the biogas production, and the best yield tends to occur at lower and/or intermediate organic loads, as this parameter also involves substrate consumption.

Phosphonium grafted styrene–divinylbenzene resins impregnated with iron(III) and crown ethers for arsenic removal

Abstract In the present work a polymer with phosphonium pendant groups impregnated with crown ether (dibenzo-18-crown-6) and loaded with iron ions was investigated for arsenic removal through adsorption from aqueous solutions. The impregnated polymer was loaded with iron ions due to the high affinity of arsenic to it. The characterization of the surface modification of the obtained new adsorbent material was performed on the basis of energy dispersive X-ray analysis; scanning electron microscopy and Fourier transform infrared spectroscopy. The arsenic adsorption was investigated, including effect of pH, arsenic initial concentration, the shaking time and temperature. The effect of the pH was examined over the range 2–11. The adsorption of As(V) increases with pH increasing reaching a maximum at pH higher than 8. Equilibrium, kinetic and thermodynamic studies were carried out to study the adsorption performance of the obtained material in the removal process of arsenic from aqueous solutions. For the studied materials the equilibrium data closely fitted Langmuir model and was achieved a maximum adsorption capacity of 32.6 μg As(V)/g of material. The pseudo-second order kinetic model is suitable for describing the adsorption system. The obtained results show that the studied adsorbent can be used with efficiency in the arsenic removal from underground water even from low influent arsenic concentration solutions.

The chemostat study of metabolic distribution in extreme-thermophilic (70°C) mixed culture fermentation.

The effects of pH, hydrogen partial pressure (PH2), and influent glucose concentration on the metabolic distribution in chemostat were investigated in this work in extreme-thermophilic mixed culture fermentation (MCF) process. The results showed that acetate, ethanol, and hydrogen were the main metabolites. A shift of ethanol to acetate and hydrogen was observed as pH increasing from 4.0 to 7.0 or PH2 decreasing from 0.64 to 0.05 atm. The maximum hydrogen yield was 3.16 ± 0.16 mol/mol glucose at PH2 0.05 atm. Lactate was only accumulated at low pH or high influent glucose concentration, while others such as butyrate and formate were rather low. Thermodynamic analysis illustrated that a mixture of acetate, ethanol, and/or lactate was essential for hydrogen production in extreme-thermophilic MCF. The hydrogen-producing rate was also calculated, and the maximum value was 2.2 ± 0.1 L/(L-reactor/day) at PH2 0.05 atm. Except hydrogen, other metabolites, such as liquid fatty acids and biofuels, could also be the producing targets in extreme-thermophilic MCF.

Humic acid transport in saturated porous media: Influence of flow velocity and influent concentration

Understanding the transport of humic acids (HAs) in porous media can provide important and practical evidence needed for accurate prediction of organic/inorganic contaminant transport in different environmental media and interfaces. A series of column transport experiments was conducted to evaluate the transport of HA in different porous media at different flow velocities and influent HA concentrations. Low flow velocity and influent concentration were found to favor the adsorption and deposition of HA onto sand grains packed into columns and to give higher equilibrium distribution coefficients and deposition rate coefficients, which resulted in an increased fraction of HA being retained in columns. Consequently, retardation factors were increased and the transport of HA through the columns was delayed. These results suggest that the transport of HA in porous media is primarily controlled by the attachment of HA to the solid matrix. Accordingly, this attachment should be considered in studies of HA behavior in porous media.

Influence of influent methane concentration on biogas upgrading and biogas slurry purification under various LED (light-emitting diode) light wavelengths using Chlorella sp.

Raw biogas is a valuable renewable energy but usually requires upgrading. The mixed LED (light-emitting diode) light wavelengths achieved much better microalgae growth than that of the monochromatic. The best LED light wavelength mix ratio for both biogas upgrading and biogas slurry nutrient removal was the red:blue ratio of 5:5. Lower influent CH4 (methane) concentration achieved higher biogas slurry nutrient removal efficiency, whereas moderate influent CH4 concentration achieved the best biogas upgrading effect. Therefore the optimal parameters were determined to lie between the low and moderate influent CH4 concentrations and the mixed red:blue ratio of 5:5 LED light wavelengths. They achieved the best biogas upgrading and biogas slurry nutrient purification effects with the following values: 92.60 ± 2.24% (v/v) of upgraded biogas CH4 concentration, 85.73 ± 4.26% of chemical oxygen demand removal efficiency, 73.21 ± 2.51% of total nitrogen removal efficiency, and 73.89 ± 4.82% total phosphorus removal efficiency.

Disinfection capacity of seven constructed wetlands and ponds

The disinfection performance of three subsurface flow constructed wetlands (SSF), a free-water surface-constructed wetland and three ponds were investigated. They functioned as advanced treatment stage following treatment in a large municipal wastewater treatment plant equipped with nutrient removal. Despite low influent concentrations of 10(3.9)/100 mL, Escherichia coli underwent a reduction of 1.7 (ditch) to 2.3 (sandy loamy SSF) orders of magnitude. After passing through these treatment plants E. coli was lowered sufficiently to within the permitted levels thus allowing it to be used in drip irrigation of fruits and vegetables. The change of seasons and hydraulic loading (in the range of 50-150 mm/day) as well as short-term overloadings did not impact the effluents' quality.

Removal of Fluoride from Aqueous Solutions by Adsorption Using a Siliceous Mineral of a Kenyan Origin

AbstractThe problem of high fluoride in water sources in Africa and the rest of the developing world has exacerbated in the latest past due to increasing shortage of water. More people are being exposed to high water fluoride resulting in elevated levels of fluorosis in the societies. Fluoride (F) adsorption from solutions using a siliceous mineral from Kenya (M1) was studied on batch basis and results verified on high fluoride water using fixed‐bed column experiments. About 100% batch F adsorption was achieved at 200 mg/L F concentration, 0.5 g/mL adsorbent dosage, 303–333 K, and pH 3.4 ± 0.2. Based on Giles classifications, F adsorption isotherm was found to be an H3 type isotherm. The equilibrium data was correlated to Freundlich and Langmuir models and the maximum Langmuir adsorption capacity was found to be 12.4 mg/g. Column experiments were conducted for different fluoride concentrations, bed depths, and flow rates. The F breakthrough curves were analyzed using the Thomas model and efficient F adsorption was found to occur at low flow rates and low influent concentrations. The Thomas F adsorption capacity (11.7 mg/g) was consistent with the Langmuir isotherm capacity showing that M1 could be applied as an inexpensive medium for water defluoridation.

Electrochemically induced dual reactive barriers for transformation of TCE and mixture of contaminants in groundwater.

A novel reactive electrochemical flow system consisting of an iron anode and a porous cathode is proposed for the remediation of mixture of contaminants in groundwater. The system consists of a series of sequentially arranged electrodes, a perforated iron anode, a porous copper cathode followed by a mesh-type mixed metal oxide anode. The iron anode generates ferrous species and a chemically reducing environment, the porous cathode provides a reactive electrochemically reducing barrier, and the inert anode provides protons and oxygen to neutralize the system. The redox conditions of the electrolyte flowing through this system can be regulated by controlling the distribution of the electric current. Column experiments are conducted to evaluate the process and study the variables. The electrochemical reduction on a copper foam cathode produced an electrode-based reductive potential capable of reducing TCE and nitrate. Rational electrodes arrangement, longer residence time of electrolytes and higher surface area of the foam electrode improve the reductive transformation of TCE. More than 82.2% TCE removal efficiency is achieved for the case of low influent concentration (<7.5 mg/L) and high current (>45 mA). The ferrous species produced from the iron anode not only enhance the transformation of TCE on the cathode, but also facilitates transformation of other contaminants including dichromate, selenate and arsenite. Removal efficiencies greater than 80% are achieved for these contaminants in flowing contaminated water. The overall system, comprising the electrode-based and electrolyte-based barriers, can be engineered as a versatile and integrated remedial method for a relatively wide spectrum of contaminants and their mixtures.

Technological options for the removal of arsenic with special reference to South East Asia

Arsenic contamination in ground water, used for drinking purpose, has been envisaged as a problem of global concern. However, arsenic contamination of ground water in parts of South East Asia is assuming greater proportions and posing a serious threat to the health of millions of people. A variety of treatment technologies based on oxidation, co-precipitation, adsorption, ion exchange and membrane process are available for the removal of arsenic from ground water. However, question remains regarding the efficiency and applicability/appropriateness of the technologies, particularly because of low influent arsenic concentration and differences in source water composition. Some of these methods are quite simple, but the disadvantage associated with them is that they produce large amounts of toxic sludge, which needs further treatment before disposal into the environment. Besides, the system must be economically viable and socially acceptable. In this paper an attempt has been made to review and update the recent advances made in the technological development in arsenic removal technologies to explore the potential of those advances to address the problem of arsenic contamination in South East Asia.

Characteristics of Nitrous Oxide (N2O) Emissions from Intermittently-Aerated Sequencing Batch Reactors Treating the Separated Liquid Fraction of Anaerobically Digested Pig Manure

In this study, the N2O emission from an intermittently aerated sequencing batch reactor (IASBR-1) treating the separated liquid fraction of anaerobically digested pig manure (SLAP) was investigated. The wastewater had chemical oxygen demand (COD) concentrations of 11,540 ± 860 mg l−1, 5-day biochemical oxygen demand (BOD5) concentrations of 2,900 ± 200 mg l−1and total nitrogen concentrations of 4,041 ± 59 mg l−1, with low COD:N ratios (2.9, on average) and BOD5:N ratios (0.72, on average). Synthetic wastewater, simulating the SLAP with similar COD and nitrogen concentrations but with higher BOD5 concentrations of up to 11,500 ± 100 mg l−1, was treated in another identical reactor (IASBR-2) to compare the effects of carbon source on nutrient removals and N2O emissions. In steady-state, soluble N2O accumulated in the non-aeration periods, with the highest N2O concentrations measured at the end of the non-aeration periods. There was a significant reduction in N2O concentrations during the aeration periods with reductions occurring immediately on commencement of aeration. The mean N2O emissions in an operational cycle were 253.6 and 205.3 mg for IASBR-1 and IASBR-2, respectively. During the non-aeration periods, only 8.3% and 8.4% of total N2O emissions occurred in IASBR-1 and IASBR-2, respectively; while during the aeration periods, 91.7% and 91.6% of N2O emissions took place in IASBR-1 and IASBR-2, respectively. The mean specific N2O generation rates were 0.010 and 0.005 mg (g VSS·min)−1 in the aeration periods, 0.024 and 0.021 mg (g VSS·min)−1 in the non-aeration periods for IASBR-1 and IABSR-2, respectively. Mean nitrogen removal via N2O emissions was 15.6% and 10.1% for IASBR-1 and IASBR-2, respectively. The IASBR-1 with low influent BOD5 concentrations emitted and generated more N2O.

Anthraquinone compounds as redox mediators for enhanced continuous-flow anaerobic biotransformation of reactive dyes under hypersaline conditions

The effect of anthraquinone disulfonate (AQDS) on the decolorization of the azo dye Reactive Red 198 (RR198) and the anthraquinone dye Reactive Blue 4 (RB4), as well as the effect of RB4 on the decolorization of RR198, both AQDS and RB4 serving as redox mediators, was assessed. An anaerobic, continuous-flow, fluidized-bed bioreactor with an immobilized halotolerant mixed culture was used in this study. All tests were performed at a reactor temperature of 35°C, a hydraulic retention time of 6.1 h, pH 7.2±0.1, with glucose used as the carbon and electron source. AQDS at relatively low influent concentrations (10–150 μM) enhanced the extent of RR198 reduction, but had a negligible effect on the biodecolorization of RB4. At an equal concentration of 50 µM, RB4 and AQDS had a similar enhancing effect on the biodecolorization of the azo dye RR198. Therefore, anthraquinone dyes can serve as redox mediators in mixed, spent textile dyebaths potentially leading to enhanced reductive biodecolorization rate and exten...

Incomplete aerobic degradation of the antidiabetic drug Metformin and identification of the bacterial dead-end transformation product Guanylurea

Active pharmaceutical ingredients as well as personal care products are detected in increasing prevalence in different environmental compartments such as surface water, groundwater and soil. Still little is known about the environmental fate of these substances. The type II antidiabetic drug Metformin has already been detected in different surface waters worldwide, but concentrations were significantly lower than the corresponding predicted environmental concentration (PEC). In human and mammal metabolism so far no metabolites of Metformin have been identified, so the expected environmental concentrations should be very high. To assess the aerobic biodegradability of Metformin and the possible formation of degradation products, three Organisation of Economic Cooperation and Development (OECD) test series were performed in the present study. In the Closed Bottle test (OECD 301 D), a screening test that simulates the conditions of an environmental surface water compartment, Metformin was classified as not readily biodegradable (no biodegradation). In the Manometric Respiratory test (OEDC 301 F) working with high bacterial density, Metformin was biodegraded in one of three test bottles to 48.7% and in the toxicity control bottle to 57.5%. In the Zahn–Wellens test (OECD 302 B) using activated sludge, Metformin was biodegraded in both test vessels to an extent of 51.3% and 49.9%, respectively. Analysis of test samples by high performance liquid chromatography coupled to multiple stage mass spectrometry (HPLC–MS( n)) showed in the tests vessels were biodegradation was observed full elimination of Metformin and revealed Guanylurea (Amidinourea, Dicyandiamidine) as single and stable aerobic bacterial degradation product. In another Manometric Respiratory test Guanylurea showed no more transformation. Photodegradation of Guanylurea was also negative. A first screening in one of the greatest sewage treatment plant in southern Germany found Metformin with high concentrations (56.8 μg L −1) in the influent (PEC = 79.8 μg L −1), but effluent concentration was much lower (0.76 μg L −1) whereas Guanylurea was detected in a low influent and high effluent concentration (1.86 μg L −1). These data support the experimental findings in the OECD tests and analytical results of other studies, that Metformin under aerobic conditions can bacterially be degraded to the stable dead-end transformation product Guanylurea.

Performance evaluation of a continuous bipolar electrocoagulation/electrooxidation–electroflotation (ECEO–EF) reactor designed for simultaneous removal of ammonia and phosphate from wastewater effluent

The present study aimed to evaluate the performance of a continuous bipolar ECEO–EF reactor designed for simultaneous removal of ammonia and phosphate from wastewater effluent. The reactor was comprised of two distinct units: electrochemical and separation. In the electrochemical unit, Al, stainless steel, and RuO 2/Ti plates were used. All the measurements were performed according to the standard methods. Maximum efficiency of the reactor for phosphate removal was 99% at pH of 6, current density of 3 A, detention time of 60 min, and influent phosphate concentration of 50 mg/l. The corresponding value for ammonia removal was 99% at a pH of 7 under the same operational conditions as for phosphate removal. For both phosphate and ammonia, the removal efficiency was highest at neutral pH, with higher current densities, and with lower influent concentrations. In addition to removal of phosphate and ammonia, application of the Al 3+ plates enabled the removal of nitrite and nitrate, which may be present in wastewater effluent and are also products of the electrochemical process. The reactor was also able to decrease the concentrations of phosphate, ammonia, and COD under actual wastewater conditions by 98%, 98%, and 72%, respectively. According to the results of the present study, the reactor can be used for efficient removal of ammonia and phosphate from wastewater.

Evaluation of stormwater BMPs for implementing industrial stormwater permitting strategy

This study assesses the performance of stormwater best management practices (BMPs) in industrial sectors and their effluent quality to facilitate the development of technology-based numerical effluent criteria. Generally, retention ponds outperform other BMP types for reducing total suspended solids, and media filter and wetland basins outperform other BMPs for metal removal. Detention basins were not effective in reducing stormwater pollution although they can retain the stormwater before entering surface waters. However, many BMPs show high variability of influent and effluent concentrations and no significant difference between them, which makes it difficult to determine the effectiveness of the BMP. In some cases, low influent concentrations govern the distribution of effluent concentrations and effluent concentrations are often greater than inflow concentrations. The analysis results can be used to assist in the developing a watershed based multisector industrial stormwater general permit to ensure compliance with total maximum daily loads. The results also suggest the need for additional monitoring data.

Removal of nitrate and hexavalent uranium from groundwater by sequential treatment in bioreactors packed with elemental sulfur and zero‐valent iron

The bioreduction of soluble hexavalent uranium (U(VI)) to insoluble tetravalent uranium (U(IV)) is an attractive bioremediation strategy for the clean-up of contaminated groundwater. High levels of the common occurring co-contaminant, nitrate (NO3(-)), can potentially interfere with uranium bioremediation. In this study, treatment of a synthetic groundwater containing a mixture of NO3(-) and U(VI) was investigated in a sulfur-limestone autotrophic denitrifying (SLAD) bioreactor that was coupled in series with a bioreactor packed with zero-valent iron (Fe(0), ZVI) and sand. An additional aim of the study was to explore the possible role of biological activity in enhancing the reduction of U(VI) by Fe(0). The SLAD reactor removed NO3(-) efficiently (99.8%) at loadings of up to 20 mmol NO3(-) L(r)(-1) d(-1), with near stoichiometric conversion to benign dinitrogen gas (N(2)). The ZVI bioreactor subsequently removed uranium (99.8%) at high (0.22 mM) and low (0.02 mM) influent concentrations of the radionuclide. Aqueous uranium was reliably eliminated to below the maximum contaminant level of 30 µg L(-1) (0.13 µM) when the ZVI reactor was operated at average empty bed hydraulic retention times as low as 2.3 h, demonstrating the feasibility of the sequential treatment strategy in packed bed bioreactors. Sequential extraction of the ZVI reactor packing confirmed that uranium was immobilized as U(IV). Uranium removal was enhanced by microbial activity as confirmed by the increased rate of uranium removal in batch assays inoculated with effluent from the ZVI bioreactor and spiked with Fe(0) compared to abiotic controls.

Impact of total organic carbon and chlorine to ammonia ratio on nitrification in a bench-scale drinking water distribution system

Nitrification occurs in chloraminated drinking water systems and is affected by water quality parameters. The aim of this study was to investigate the impact of total organic carbon and chlorine to ammonia ratio on nitrification potential in a simulated drinking water distribution system as during chloramination. The occurrence of nitrification and activity of nitrifying bacteria was primarily monitored using four rotating annular bioreactors (RAB) with different chlorine to ammonia ratios and total organic carbon (TOC) levels. The results indicated that nitrification occurred despite at a low influent concentration of ammonia, and a high concentration of nitrite nitrogen was detected in the effluent. The study illustrated that reactors 1(R1) and 3 (R3), with higher TOC levels, produced more nitrite nitrogen, which was consistent with the ammonia-oxidizing bacteria (AOB) counts, and was linked to a relatively more rapid decay of chloramines in comparison to their counterparts (R2 and R4). The AOB and HPC counts were correlated during the biofilm formation with the establishment of nitrification. Biofilm AOB abundance was also higher in the high TOC reactors compared with the low TOC reactors. The chlorine to ammonia ratio did not have a significant impact on the occurrence of nitrification. Bulk water with a high TOC level supported the occurrence of nitrification, and AOB development occurred at all examined chlorine to ammonia dose ratios (3:1 or 5:1).

Ozonation as a Means to Optimize Biological Nitrogen Removal from Landfill Leachate

In this study, we investigate factors that can affect nitrification and denitrification in a moving bed biofilm system, treating partly stabilized landfill leachate. The optimization of biological treatment by means of controlled ozonation is additionally evaluated. Results obtained with a laboratory-scale, continuous-flow biofilm system suggest that nitrogen removal can be limited by the low influent biodegradable substrate concentrations, and that autotrophic nitrification can be adversely impacted by the high alkalinity buffer and ammonium/ammonia concentration. Our results suggest an optimum ozone dosage as high as 0.5 g/L O3 can be required to effectively decrease the effluent soluble COD concentration and pH profile in the aerobic reactors, improve the biodegradable COD production from inert compounds, and induce chemical nitrification in the system. The specific cost of ozonation evaluated is 0.36–0.73 euro/m3 with 911 mg/L average effluent soluble COD measured in the biofilm system.

Effects of water vapor on activated carbon load equalization of gas phase toluene

Experimental testing and numerical simulations were conducted to assess the effects of elevated water vapor concentrations on the ability of granular activated carbon (GAC) to achieve load equalization of dynamically varying gas-phase toluene concentrations. Columns packed with Calgon BPL 4 × 6 mesh GAC were subjected to intermittent (8 h/day) toluene loading in air streams containing up to 90% relative humidity. Influent toluene concentrations ranged from 100 to 1000 ppm v, and GAC column empty bed residence times ranged from 1.5 to 10 s. In comparison to load equalization performance achieved with dry air, high relative humidity improved load attenuation at high influent toluene concentration (e.g., 1000 ppm v) but decreased the degree of load attenuation at low influent toluene concentration (e.g., 100 ppm v). Model simulations conducted using a pore and surface diffusion model were in good general agreement with experimental observations. Collectively, results demonstrate that GAC columns can be of practical benefit as passively-operated load equalization devices even in the case of high relative humidity. Such systems may prove useful as a pre-treatment process for biofilters and other air pollution control devices that would otherwise be subjected to wide variation in contaminant loading.

Performance evaluation and mathematical modelling of granular activated carbon biofiltration in wastewater treatment

Biological filtration is an effective technique for removing organic matter from wastewater. The perfor- mance of a biofilter can be influenced by a range of operational conditions. In this study the performance of biofilters was investigated for the influence of filter media depth, influent concentrations, filtrations rates and backwashing. The results show that performance of GAC filters decreased with shallower filter bed depths. In addition, the GAC per- formed better at lower influent concentration and lower filtration rates. The daily backwash adopted to avoid the phys- ical clogging of the biofilter did not have any significant effect on the organic removal efficiency of the filter. The con- centration, activity and characteristics of the biomass are quantified and described. A mathematical model was devel- oped to simulate the organic removal of the GAC biofiltration system. The performance of the GAC filter under dif- ferent influent organic concentration levels, filtration rates and filter bed depths was adequately simulated by the math- ematical model developed for this study.