Biological Activated Carbon Reactor Research Articles

Kinetics and Performance of Biological Activated Carbon Reactor for Advanced Treatment of Textile Dye Wastewater

The kinetics and performance of a biological activated carbon (BAC) reactor were evaluated to validate the proposed kinetic model. The Freundlich adsorption capacity (Ka) and adsorption intensity constants (n) obtained from the batch experiments were 1.023 ± 0.134 (mg/g) (L/mg)1/n and 2.036 ± 0.785, respectively. The effective diffusivity (Ds) of the substrate within the activated carbon was determined by comparing the adsorption model value with the experimental data to find the best fit value (4.3 × 10–4 cm2/d). The batch tests revealed that the yield coefficient (Y) was 0.18 mg VSS/mg COD. Monod and Haldane kinetics were applied to fit the experimental data and determine the biokinetic constants, such as the maximum specific utilization rate (k), half-saturation constant (KS), inhibition constant (Ki), and biomass death rate coefficient (kd). The results revealed that the Haldane kinetics fit the experimental data better than the Monod kinetics. The values of k, KS, Ki, and kd were 3.52 mg COD/mg VSS-d, 71.7 mg COD/L, 81.63 mg COD/L, and 4.9 × 10−3 1/d, respectively. The BAC reactor had a high COD removal efficiency of 94.45% at a steady state. The average influent color was found to be 62 ± 22 ADMI color units, and the color removal efficiency was 73–100% (average 92.3 ± 10.2%). The removal efficiency for ammonium was 73.9 ± 24.4%, while the residual concentration of ammonium in the effluent was 1.91 ± 2.04 mg/L. The effluent quality from the BAC reactor could meet the discharge standard and satisfy the reuse requirements of textile dye wastewater.

Water recycle system in an artificial closed ecosystem – Lunar Palace 1: Treatment performance and microbial evolution

Water recycle systems have important implications to realize material circulation in biological regeneration life support systems, which is of significance for long-term space missions and future planetary base. Based on membrane biological activated carbon reactor (MBAR) technologies, the ‘Lunar Palace 365’ experiment established various treatment processes for condensate wastewater, domestic wastewater, urine, and used nutrient solutions. The 370-day operation data showed the CODMn index of purified condensate wastewater decreased to 0.74 ± 0.15 mg/L, which met the standards for drinking water quality. The average removal rate of organic contaminants in domestic wastewater by the MBAR was 85.7% ± 10.2%, and this MBAR also had a stable nitrification performance with effluent NO3−-N concentrations fluctuating from 145.57 mg/L to 328.59 mg/L. Moreover, the purification of urine achieved the conversion of urea-N to NH4+-N and thus the partial recovery of nitrogen. 16S rDNA sequencing results revealed the evolution of microbial diversity and composition during the long-term operation. Meiothermus, Rhodanobacter, and Ochrobactrum were the dominant microorganisms in various MBARs.

Treatment and hybrid modeling of domestic reverse osmosis concentrate using biological activated carbon

The simulation and removal of organics from municipal reverse osmosis concentrate (ROC) using biological activated carbon (BAC) was investigated. BAC treatment of ROC achieved a TOC removal of 25.5% and 28.1% for empty bed contact time (EBCT) of 40 min and 60 min, respectively. Batch studies revealed that the TOC removal followed a first order reaction with a rate constant of 2.735 at R2 > 0.98. Most of the organics were removed within 80 min of treatment, with an average non-biodegradable fraction of 0.6453. The results obtained from the batch studies were then used for simulation of the continuous lab-scale BAC reactors, yielding average relative deviations of 7%–8% and normalized root mean square errors (RMSE) of 0.09–0.1. Results from a third reactor with EBCT of 80 min were used to train and verify a machine learning model. The model was then used for calculating the non-biodegradable organics fraction of ROC, which will be fed into the first order reaction model. The resulting serial hybrid modeling further reduced the average relative deviations to 5%–6% and a normalized RMSE of 0.08.

Effect of shear stress and carbon surface roughness on bioregeneration and performance of suspended versus attached biomass in metoprolol-loaded biological activated carbon systems

The bioregeneration of activated carbon (AC) in biological activated carbon (BAC) systems is limited by sorption-desorption hysteresis and transport between the adsorbent and biomass. In this study, we investigated these limitations and whether a biofilm covering the AC surface is required. Consequently, BAC reactors were operated at different shear stress and AC surface smoothness, since this may affect biofilm formation. The experiments were carried out in BAC and blank reactors treating synthetic wastewater containing the pharmaceutical metoprolol.After start-up, all reactors removed metoprolol completely; however, after 840h the removal dropped due to saturation of the AC. In the blank reactors, the removal dropped to 0% while in the BAC reactors removal recovered to >99%, due to increased biological activity. During the initial phase, the metoprolol was adsorbed, rather than biodegraded. At the end, the AC from the BAC reactors had higher pore volume and sorption capacity than from the blank reactors, showing that the AC had been bioregenerated.At high shear (G=25s−1), the rough AC granules (Ra=13μm) were covered with a 50–400μm thick biofilm and the total protein content of the biofilm was 2.6mg/gAC, while at lower shear (G=8.8s−1) the rough AC granules were only partly covered. The biofilm formation at lower shear (G=8.8s−1) on smooth AC granules (Ra=1.6μm) was negligible. However, due to the presence of suspended biomass the reactor performance or bioregeneration were not reduced. This showed that direct contact between the AC and biomass was not essential in mixed BAC systems. The microbial analyses of the suspended biomass and the biofilm on AC surface indicated that metoprolol was mainly biodegraded in suspension.

Influence of Biological Activated Carbon on Simultaneous Nitrification and Denitrification in Inflow with Different C/N Ratios

Influence of biological activated carbon (BAC) on simultaneous nitrification and denitrification (SND) in inflow with different C/N ratios was investigated with continuous operation of BAC reactor and SBR. Methanol was added as carbon source and the inflow C/N ratio was set to 3, 5, 8 and 10 to run for about 120 cycles, under conditions of indoor temperature (15-27℃), initial DO 2-3mg·L-1. The TN removal efficiency and stability of two reactors were compared. The results showed that, BAC reactor had a higher TN removal efficiency than SBR at different C/N ratios. TN removal rate of BAC reactor was 44.88%, 58.07% and 66.64%, when the C/N ratio was 3, 5 and 8 respectively. After increasing the C/N ratio to 10, the BAC reactor could maintain TN removal rate of 63.65%, but the SBR showed sludge bulking. BAC provided various DO environments for microorganisms in a vessel, which was beneficial to SND. BAC could reduce the influence of excessive carbon source on the nitrification system, enlarge the application range and improve the stability of reactor at different C/N ratios, and increase the nitrogen removal capacity of organic matter. BAC provided condition for efficient nitrogen removal.

Treatment of flotation wastewater using biological activated carbon

A laboratory scale up-flow biological activated carbon (BAC) reactor was constructed for the advanced treatment of synthetic flotation wastewater. Biodegradation of a common collector (i.e., ethyl xanthate) for non-ferrous metallic ore flotation was evaluated. The results show that the two stages of domestication can improve microbial degradation ability. The BAC reactor obtains a chemical oxygen demand (COD) reduction rate of 82.5% for ethyl xanthate and its effluent COD concentration lowers to below 20 mg/L. The kinetics equation of the BAC reactor proves that the activated carbon layers at the height of 0 mm to 70 mm play a key role in the removal of flotation reagents. Ultraviolet spectral analysis indicates that most of the ethyl xanthate are degraded by microorganisms after advanced treatment by the BAC reactor.

Removal of anaerobic soluble microbial products in a biological activated carbon reactor

The soluble microbial products (SMP) in the biological treatment effluent are generally of great amount and are poorly biodegradable. Focusing on the biodegradation of anaerobic SMP, the biological activated carbon (BAC) was introduced into the anaerobic system. The experiments were conducted in two identical lab-scale up-flow anaerobic sludge blanket (UASB) reactors. The high strength organics were degraded in the first UASB reactor (UASB1) and the second UASB (UASB2, i.e., BAC) functioned as a polishing step to remove SMP produced in UASB1. The results showed that 90% of the SMP could be removed before granular activated carbon was saturated. After the saturation, the SMP removal decreased to 60% on the average. Analysis of granular activated carbon adsorption revealed that the main role of SMP removal in BAC reactor was biodegradation. A strain of SMP-degrading bacteria, which was found highly similar to Klebsiella sp., was isolated, enriched and inoculated back to the BAC reactor. When the influent chemical oxygen demand (COD) was 10,000 mg/L and the organic loading rate achieved 10 kg COD/(m3·day), the effluent from the BAC reactor could meet the discharge standard without further treatment. Anaerobic BAC reactor inoculated with the isolated Klebsiella was proved to be an effective, cheap and easy technical treatment approach for the removal of SMP in the treatment of easily-degradable wastewater with COD lower than 10,000 mg/L.

A Study on Advanced Treatment for Coking Wastewater with Biological Activated Carbon Based on Efficient Degrading Flora

The removal efficiency of degrading flora which has been constructed is investigated in biological carbon process through the variation of COD and chromaticity. The results show that the efficient degrading strains can reproduce on the activated carbon quickly；the biological activated carbon reactor，in which degrading flora to coking waste water are inoculated，is adopted to carry out the treatment of wastewater，in such a way the COD and chromaticity in outflow water can remain at a lower level (with COD about 50mg/L and chromaticity about 50 degree). The average COD removal rate is 71% and the chromaticity removal ratio is 95%.

Treatment of wastewater from acrylonitrile‐butadiene‐styrene (ABS) resin manufacturing by biological activated carbon (BAC)

AbstractBackground: The wastewater originating from the production of acrylonitrile‐butadiene‐styrene (ABS) resin is a toxic and refractory industrial wastewater. The purpose of this work is to investigate the characteristics of adsorption and biodegradation of biological activated carbon (BAC) for ABS resin wastewater.Results: More than 80% of chemical oxygen demand (COD), total organic carbon (TOC) and organic nitrogen (Org‐N) was removed after the 100th run in BAC with the help of bioregeneration, and the treatment efficiency of BAC was higher than that of adsorption and biodegradation alone. The initial Org‐N was mainly transformed into NH4+‐N, and the transform efficiency reached 65% after the 100th run. After bioregeneration, the COD and TOC removal efficiencies of BAC reactor reached 88.97% and 86.26%, respectively. The BAC had different bioregeneration efficiencies of 94.41, 64.82, 61.05 and 40.04% for 3, 3‐imminodipropiononitrile, 3, 3‐oxydipropiononitrile, α, α‐dimethyl‐benzylalcohol and acetophenone, respectively, which mainly resulted from the different polarity of the compounds.Conclusion: BAC could protect microorganisms from shock loadings of toxic, refractory and complicated ABS resin wastewater. The mechanism of the organic pollutants removal by BAC consisted of three phases including adsorption, bioregeneration and stability. © 2012 Society of Chemical Industry

Effect of PAC Addition on the Physicochemical Characteristics of Bio-Cake in a Membrane Bioreactor

The effect of powdered activated carbon (PAC) addition on the architecture and cohesion strength of bio-cake in a membrane bioreactor (MBR) was investigated. Two reactors, a conventional MBR and a membrane-coupled biological activated carbon reactor (MBR ac ), were run in parallel. The addition of PAC led to a substantial increase in membrane permeability. Based on the conventional filtration theory, microbial floc size (d), bio-cake porosity (ε), and total attached biomass (TAB) were determined to find the key mechanism for the enhanced permeability. Unexpectedly the addition of PAC did not significantly change either the microbial floc size (d) or the porosity (ε) of the bio-cake. It decreased, however, not only the concentration of extra-cellular polymeric substances (EPS) in the bulk phase but also the TAB on the membrane. Using a separate batch cohesion test, it was revealed that the cohesion strength between microorganisms in the bio-cake in the MBR ac was weaker than that in the MBR. The addition of PAC led to the reduction of EPS, which act as glue-like materials, which in turn weakened the cohesion strength of the microorganisms. This resulted in a lower amount of TAB, i.e., a smaller amount of the bio-cake on the membrane, which ultimately gave rise to the enhanced permeability in the MBR ac .

Extracellular proteomic analysis for degradation of PAHs in source of drinking water with fusant strains

Extracellular proteomic expressions of two fusant strains were analyzed to observe their abilities to degrade polycyclic aromatic hydrocarbons (PAHs) in the source of drinking water from Yangtze River. The extracellular proteomes for the hybrid strains, Fhhh and Xhhh, and one of their parental strain Phanerochaete chrysosporium were measured by the two-dimensional electrophoresis and MS/MS. The similarity of proteome expression was 34.7% between Fhhh and P. chrysosporium and that was 28.6% between Xhhh and P. chrysosporium. PAHs degeneration performance for Fhhh, Xhhh and the native bacterium NJ2007 was studied by biological activated carbon reactor. The specific degradation rate of Fhhh for PAHs was 3.05 x 10(-5) day(-1) which was significantly higher than that of the NJ2007 and Xhhh (P < 0.05). The results indicate that the fusant strain could not express the same proteome as that of its parental strain but could degrade PAHs in the source water with higher efficiency.

An industrial-scale biodegradation system for volatile organics contaminated wastewater from semiconductor manufacturing process

Among all organic solvents, 2-propanol (isopropyl alcohol, IPA) and 2-propanone (acetone) are extensively used for wafer cleaning in semiconductor industries due to their relative high volatilities. However, the excess organic solvents always enter the wastewater treatment system along with impurities and result in a much higher chemical oxygen demand (COD) loading. Therefore, wastewater and gas phase contaminated by 2-propanol and 2-propanone has to be treated properly prior to discharge not only to meet the stipulated regulations, but also keep the health impact away. In this study, an integrated biodegradation system was constructed to remove 2-propanol and 2-propanone in the wastewater from the semiconductor manufacturing process. Special microorganisms were screened and inoculated onto granular-type activated carbon and packed carrier to give the biological activated carbon (BAC) reactors and biofilter, which were adopted to deal with wastewater and emitting gas, respectively. During the operation, with a well manipulation of the concentration of dissolved oxygen (DO) and necessary nutrients in BAC reactors and biofilter, the residual 2-propanol and 2-propanone in wastewater and flue gas can be eliminated successfully. The operating results show that when the total hydraulic retention time (HRT) is controlled as 24 h, the removal efficiency of COD in wastewater can reach 97% higher and the residual COD in emitting gas can be reduced to less than 0.1% even with a COD loading as high as 1440 mg/L. Under this condition, the COD value of the final effluent can meet the regulated limit, i.e. 100 mg/L. After a long-term operation, the running cost needed for this integrated system is estimated to be 2.5 NTD/m 3 wastewater. It can be concluded that the problem of 2-propanol and 2-propanone treatment pertaining to the semiconductor industries can be solved effectively with high economical and practical feasibilities.

Evaluation of a pilot scale dual media biological activated carbon process for drinking water

This study was carried out to optimize a dual media BAC (biological activated carbon) process for DOC removal and DBPs (disinfection by-products) control. Pilot scale tests were coducted at the Tukdo water treatment plant in Seoul, Korea. The dual media BAC process is highly efficient in the removal of DOC and THMFP, and is more capable of sustaining microorganisms than a single layer filter. The bottom layer of the sand filter functioned as a screen for turbidity, microorganisms, and other biological material. Total DOC removal efficiency was 13 to 25%, and the corresponding THMFP (trihalomethane formation potential) removal efficiency was approximately 20 to 33%. Turbidity and DOC leakage continued for 40 min after backwashing in all reactors. Breakthrough occurred from 24-72 hours in each reactor. Ten species of microorganisms were identified in the activated carbon filled in BAC reactors. The predominant species were Clavibactor and Corynebacterium and microbial species were simple at the lower end.

流入基質の切替わりに対する生物活性炭の応答

Parallel studies using biological activated carbon (BAC) and sand with bioactivity were conducted to evaluate the response of BAC to changes of substrate inflow. Low molecular weight substances with different biodegradability and adsorbability, i.e, 2,4-dichlorophenol (2,4-DCP), phenol, glucose, were fed into BAC and sand reactors. The influent substrate was changed from glucose to phenol (I), from phenol to glucose (II), and from 2,4-DCP to glucose and back to 2,4-DCP (III). In case of (I), effluent DOC concentration in the sand reactor increased temporarily by the change in influent substrate, because acclimation time was necessary for the new substrate. However, the BAC reactor removed the new substrate without any lag time because the new substrate was removed by adsorption. In case of (II), BAC reactor showed better performance than the sand reactor after the change in influent substrate, however, effluent DOC concentration in the BAC reactor also increased. The difference in the BAC performance between (I) and (II) was due to the different adsorbability of the new substrates, i.e, phenol with high adsorbability easily adsorbed on BAC after the change influent substrate from glucose to phenol and glucose with low adsorbability could hardly adsorb on BAC after the change influent from phenol to glucose. The change in influent substrate from 2,4-DCP to glucose (III) made the effluent DOC concentration increase in both reactors and the biodegradation to glucose in the BAC reactor delayed in comparison with sand reactor. Because 2,4-DCP has high adsorbability and desorbability, desorbed 2,4-DCP inhibited biodegradation of glucose after the change in influent substrate. Re-inflow of 2,4-DCP in day 12 did not increase effluent DOC concentration, because 2,4-DCP has high adsorbability and BAC kept biodegradability to 2,4-DCP by biodegradation of the desorbed 2,4-DCP during inflow of glucose.

Development of a combined BAC and BZ reactor for removal of nitrogen in wastewater from sludge drying process

A combined biological activated carbon (BAC) and biological zeolite (BZ) reactor is under development to remove organics and nitrogen from wastewater which contains both inhibitory organics to nitrification and high concentration of ammonium nitrogen. In this study, the combined BAC and BZ reactor was applied to treatment of scrubber-washed wastewater from sludge drying process. Successful treatment performance was accomplished by decreases in concentrations of the inhibitory organics (in BAC tank) and ammonium nitrogen (in BZ tank) occurred by both adsorption to the mediums and biological reaction. Appropriate nitrogen loading rate for fine and stable treatment was shown to be less than 7 mgNOx−-N · (gGAC · d)−1 for denitrification in BAC tank less than 4 mgHN4+-N · (gZeolite · d)−1 for nitrification in BZ tank. DOC/NOx−-N loading ratio to BAC tank is required to be more than 2.0 mgDOC · (mgNOx−-N)−1 for successful denitrification.

Development of a combined BAC and BZ reactor for removal of nitrogen in wastewater from sludge drying process

A combined biological activated carbon (BAC) and biological zeolite (BZ) reactor is under development to remove organics and nitrogen from wastewater which contains both inhibitory organics to nitrification and high concentration of ammonium nitrogen. In this study, the combined BAC and BZ reactor was applied to treatment of scrubber-washed wastewater from sludge drying process. Successful treatment performance was accomplished by decreases in concentrations of the inhibitory organics (in BAC tank) and ammonium nitrogen (in BZ tank) occurred by both adsorption to the mediums and biological reaction. Appropriate nitrogen loading rate for fine and stable treatment was shown to be less than 7 mgNOx−−N −(gGAC−d)−1 for denitrification in BAC tank and less than 4 mgNH4+−N−(gZeolite−d)−1 for nitrification in BZ tank. DOC/NOx−−N loading ratio to BAC tank is required to be more than 2.0 mgDOC−(mgNOx−−N)−1 for successful denitrification.

Biodegradation of Organic Substances by Biological Activated Carbon – Simulation of Bacterial Activity on Granular Activated Carbon

Biodegradation of organic substances by attached bacteria on biological activated carbon (BAC) was studied to clarify the advantages of granular activated carbon (GAC) as support media over conventional media without adsorption capacity with regard to biodegradation activity and community structure of attached bacteria. Anthracite (AN) was used as reference support medium without adsorbability. Low molecular organic substances with different biodegradability and adsorbability (phenol, glucose, benzoic acid and m-aminobenzoic acid) were fed into completely mixed BAC and AN reactors. The rate of biodegradation by BAC reactors fed with biodegradable organic substances was approximately 3 times as high as that by AN reactors. The difference in adsorbability of organic substances onto GAC had little effects on the rate of biodegradation. The structure of GAC with micro and macro pores did not provide better habitat for attached bacteria with regard to the size of population in comparison with anthracite without pores. The rates of biodegradation per attached bacteria for biodegradable organic substances in the BAC reactors were from 1.7 to 4.9 times higher than those in the AN reactors. GAC, as a bacterial support media, stimulated the biodegradation activity of each bacteria without increase in their population and probably with little change in their species composition. Although the number of attached bacteria on BAC was not different significantly from that on anthracite, m-aminobenzoic acid with low biodegradability was degraded only by the GAC reactor.

生物活性炭による低濃度有機化合物の分解除去

Biodegradation of organic substances by attached bacteria on biological activated carbon (BAC) was studied to clarify the advantages of granular activated carbon (GAC) as a support medium over conventional medium without adsorption capacity with regard to biodegradation activity and community structure of attached bacteria. Anthracite (AN) was used as a reference support medium without adsorbability. Low molecular organic substances with different biodegradability and adsorbability (phenol, benzoic acid, glucose and m-aminobenzoic acid) were fed into completely mixed BAC and AN reactors. The rates of biodegradation by BAC reactors fed with the biodegradable organic substances were approximately 3 times as high as those by AN reactors. The difference in adsorbability of the organic substances onto GAC had little effect on the rate of biodegradation. m-Aminobenzoic acid with low biodegradability was degraded only by the BAC reactor. The structure of GAC with micro and macro pores did not provide better habitat for attached bacteria with regard to the size of population in comparison with AN without pores. Bacterial floras on GAC was probably little difference from those on anthracite. Therefore GAC as a bacterial support medium stimulated the biodegradation activity of each bacterium without increase in the population and probably with little change in the species composition.

Ozone: A Means of Stimulating Biological Activated Carbon Reactors

Abstract To reduce the formation of chlorination byproducts in drinking water, the European strategy consists in developing techniques for the removal of organic matter. No chlorine is added to the water until the end of the treatment line, allowing a great reduction of the chlorine dose applied. Delaying the chlorination also improves the biological assimilation of organics within the filters. Identification of the basic properties (i.e., molecular weight, biodegradability) of the molecules which react with chlorine shows that the combination of ozone and biological activated carbon (BAC) filtration is an efficient and economical technique for the removal of these undesirable byproducts. More and more, drinking water suppliers are faced with the worrisome problem of chlorinated byproducts. This concern was prompted largely by the degradation of raw waters. Chlorinated byproducts are caused by the effect of chlorine on organic matter dissolved in water.