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A novel and high‐rate anaerobic sequencing bath reactor (ASBR) process was used to evaluate the hydrogen productivity of an acid‐enriched sewage sludge microflora at a temperature of 35 °C. In this ASBR process a 4 h cycle, including feed, reaction, settle, and decant steps, was repeatedly performed in a 5 L reactor. The sucrose substrate concentration was 20 g COD/L; the hydraulic retention time (HRT) was maintained at 12–120 h at the initial period and thereafter at 4–12 h. The reaction/settle period ratio, which is the most important parameter for ASBR operation was 1.7. The experimental results indicated that the hydrogenic activity of the sludge microflora was HRT‐dependent and that proper pH control was necessary for a stable operation of the bioreactor. The peak hydrogenic activity value was attained at an HRT of 8 h and an organic loading rate of 80 kg COD/m3 × day. Each mole of sucrose in the reactor produced 2.8 mol of hydrogen and each gram of biomass produced 39 mmol of hydrogen per day. An overly‐short HRT might deteriorate the hydrogen productivity. The concentration ratios of butyric acid to’acetic acid, as well as volatile fatty acid and soluble microbial products to alkalinity can be used as monitoring indicators for the hydrogenic bioreactor. 相似文献
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The ability of Candida bombicola ATCC 22214 to produce sophorolipids using Turkish corn oil and honey was investigated. Shake flask experiments were carried out both with and without the addition of glucose as the second carbon source. The organism could produce sophorolipids under both conditions but higher production was obtained when corn oil was combined with glucose. The 3 L bioreactor was first operated in batch mode, using both corn oil and glucose. When all the glucose was consumed, 1/4th of the broth was pumped out and was replaced by freshly prepared medium containing 10 % [w/v] of cheap market honey as the sole carbon source. Feed was comprised of corn oil. High concentrations of sophorolipids (> 400 g/L) were produced. The crude products obtained from the batch cultivation could be solidified as very light brown solids when unused oil was removed by hexane, while the products of the two‐stage cultivation remained as viscous, honey‐like liquids after identical treatments. 相似文献
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The long‐term growth process of two microbial consortia effective in the aerobic cometabolic biodegradation of a mixture of 6‐chlorinated aliphatic hydrocarbons (CAHs), the effectiveness of these consortia as inocula for the bio‐augmentation of different types of microcosms and the development of a double‐substrate, high‐performing consortium is presented. The propane‐utilizing consortium generally proved to be the most effective one, being able to biodegrade vinyl chloride, cis‐ and trans‐1,2‐dichloroethylene, trichloroethylene, 1,1,2‐trichloroethane and 1,1,2,2‐tetrachloroethane at all the CAH concentrations tested (0–4 μM). Both consortia maintained unaltered CAH degradation capacities over a 300‐day growth period in the absence of the CAHs and were effective in inducing the rapid onset of CAH depletion upon inoculation in slurry microcosms set up with five types of aquifer materials. A consortium supplied with both methane and propane combined the best degradation capacities of the two single‐substrate consortia, and maintained stable performances for 150 days under slurry conditions. The degree of conversion of the organic Cl to chloride ions was equal to 90 %. 相似文献
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The wastewater from a modern Portuguese wine producing cooperative has been characterized by an automatic sampler which allowed for the collection of daily and hourly averaged samples in two distinct representative situations: the vintage and non‐vintage periods of the year. Continuous data of room and wastewater temperatures, pH and flow rate were stored in a data logging system. The winery sells most of the husk and settled sour vine to distilleries, which reduces the quantity of waste and the wastewater pollution load as well as providing an additional source of income. However, the concentration values were higher than the limits allowed by the local authority for discharge into the municipal sewage system; therefore, lab‐scale tests were carried out using an anaerobic hybrid filter, to get comparative data on the feasibility of such an anaerobic process to pre‐treat this wastewater. The main results, obtained during 7 months of experimentation, indicate that satisfactory COD removals (0.65–0.90) can be ensured by this reactor configuration at relatively low hydraulic retention times (2–3 d), which makes this solution simple and favorable for application in this case study. 相似文献
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The goal of this work is to develop a mathematical model to describe a continuous aerobic membrane bioreactor (MBR) for the treatment of different kinds of wastewater. Firstly, the experimental setup and the materials and methods to obtain data for the model verification are described. Secondly, a black box model is developed and verified for size containing wastewater. The model calculates output streams and concentrations from input streams and compositions using distribution coefficients. These coefficients are derived from experimental data. In a third step, two shortcut models of different complexity are developed. Both shortcut models use the black box balancing as a basis. However, the component balances for carbon and oxygen are no longer modeled by constant distribution coefficients. The basic shortcut model introduces Monod kinetics to modify the carbon balance. The enhanced shortcut model introduces transport laws for dissolved oxygen supply and combines the Monod kinetics with an additional term for oxygen limitation to model biological growth. The models show an increasing degree of agreement. 相似文献
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A rigorous approach to mathematical modeling of a continuous aerobic membrane bioreactor (MBR) for the treatment of wastewater is reported. The idea is to apply the activated sludge model ASM3 to the special configuration of a membrane bioreactor. Therefore, the biochemical processes modeled by the ASM3 were implemented together with mass balances typical of a MBR running at constant TSS. The model parameters were adapted to the properties of an artificial wastewater by using a global search algorithm. The model could be validated by comparing effluent chemical oxygen demand (COD), sludge production and CO2 concentration in the exhaust to the experimental data. 相似文献
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D.B. Kosolapov P. Kuschk M.B. Vainshtein A.V. Vatsourina A. Wießner M. Kstner R.A. Müller 《Engineering in Life Science》2004,4(5):403-411
This paper reviews the main microbial processes involved when toxic metals are removed from wastewater in constructed wetlands. Microbial activity is thought to play a key role in the detoxification of these metals. The paper concentrates on the microbial processes which affect the mobility, the toxicity and bioavailability of metals, namely biosorption, metal sulfide precipitation by sulfate reducers, redox transformations, and methylation, as well as microbe‐plant interactions. These reactions result in either the precipitation and accumulation of metals in wetland soils, or their volatilization and emission into the atmosphere. The possibilities of optimizing the microbially mediated reactions for the development of wetland technology are discussed as a long‐term metal retention strategy. 相似文献
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It is proposed a dynamic model for adsorption of NH4+ ions from ammonia waters on volcanic tuff in a 10‐bed three‐phase (air – ammonia waters – volcanic tuff) fluidization column. The model consists in the nonstationary material balance differential equations. For each layer the ideal well‐mixing conditions are considered. The effluent ammonia ion concentrations, corresponding to each layer, have been measured at several time values in a laboratory‐scale column. The absolute relative mean error between the calculated and measured values of ammonia ion concentrations into liquid phase for all layers and times is 6.65 %, being in the order of magnitude of experimental errors. 相似文献
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In a study where the removal of heavy metals from wastewater is the primary aim, the biosorption of heavy metals onto biosolids prepared as Pseudomonas aeruginosa immobilized onto granular activated carbon was investigated in batch and column systems. In the batch system, adsorption equilibriums of heavy metals were reached between 20 and 50 min, and the optimal dosage of biosolids was 0.3 g/L. The biosorption efficiencies were 84, 80, 79, 59 and 42 % for Cr(VI), Ni(II), Cu(II), Zn(II) and Cd(II) ions, respectively. The rate constants of biosorption and pore diffusion of heavy metals were 0.013–0.089 min–1 and 0.026–0.690 min–0.5. In the column systems, the biosorption efficiencies for all heavy metals increased up to 81–100 %. The affinity of biosorption for various metal ions towards biosolids was decreased in the order: Cr = Ni > Cu > Zn > Cd. 相似文献
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Synthetic wastewater was treated in a bench scale submerged membrane bioreactor (SMBR). A long‐term experiment was conducted by varying the sludge residence time (SRT) (10–500 d) and BOD loading (1.3–0.25 kg/m3·d). The biological activity was observed in terms of the oxygen utilization rate (OUR) and adenosine triphosphate (ATP) profile; the process stability was analyzed based on the extent of organic degradation and suction pressure. The microbial population in the SMBR was dependent on the SRT and BOD loading, and its biological activity was increased with an increase in the SRT or BOD loading. At a low feed to microorganism (F/M) ratio (0.06 kg BOD/kg MLSS·d), the sludge production of the reactor was reduced to 0.04 kg MLSS/kg BOD, which is much less than in the conventional activated sludge process (0.4–0.6 kg MLSS/kg BOD). The F/M ratio influenced the biological activity (via ATP and the OUR) significantly at a short SRT (≤90 d). However, the effect of the F/M ratio ceased at a low F/M ratio (≤ 0.07 kg BOD/kg MLSS·d). The accumulation of organics in the SMBR was accompanied with an increase in the supernatant TOC, which caused a high suction pressure and an abrupt change in the operating conditions to process instability. However, the process stability of the SMBR increased with an increase in the SRT and a decrease in the BOD loading along with a concomitant decrease in the biological activity and sludge production. 相似文献
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Availability of good quality water for crop irrigation is a big challenge in developing countries due to limited resources of clean water. Textile industry consumes a huge amount of water during dyeing process and consequently it releases high strength wastewater into wastewater streams. The present study was designed with the objective to use textile wastewater treated in sequencing batch bioreactor for irrigation purpose. Wastewater containing 100 mg/L reactive black-5 azo dye amended with different co-substrates was treated using mixed liquor suspended solids (MLSS) and two previously isolated dye-degrading bacterial strains (Psychrobacter alimentarius KS23 and Staphylococcus equorum KS26). About 90% color and COD removal in case of dye-containing wastewater amended either with mineral salts + yeast extract or only yeast extract was achieved in 24 h after treatment with mixed culture (MLSS + KS23 + KS26). The treated wastewater was applied for irrigation of pea and wheat plants under controlled conditions. Untreated dye-contaminated wastewater was used as a control for comparison. A significant positive effect of treated dye wastewater amended with different co-substrates on the seed germination index, root and shoot length and biomass was observed in response to application of dye-containing wastewater treated with MLSS and dye-degrading bacterial strains compared to untreated control. Results of this study reveal that the dye-degrading microbial cultures could be used to enhance the treatment efficiency of dye-contaminated wastewater that can be utilized for irrigation of crops and biomass production. 相似文献
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Guo H Zhou J Jing W Zhang X Zhang Z Uddin MS 《Bioprocess and biosystems engineering》2005,27(4):249-254
A novel combined biofilm reactor was established and applied as a single treatment unit for carbon and nitrogen removal of
wastewater. The nitrogen removal performance of the reactor at different levels of organic carbon (COD) loading was investigated
when the influent total nitrogen (TN) loading was 0.74 g TN/m2 day. Continuous experimental results demonstrated that 80% nitrogen was eliminated when the influent COD loading ranged between
2.06 g and 3.92 g COD/m2 day. Microbial composition in the reactor was analyzed using fluorescent in situ hybridization (FISH) and conventional batch
tests. The relative abundance of ammonia-oxidizing bacteria in the aerobic zone of the reactor measured by FISH was consistent
with the result from conventional batch tests. 相似文献
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Hossein Jafari Mansoorian Amir Hossein Mahvi Ahmad Jonidi Jafari Mohammad Mehdi Amin Ahmad Rajabizadeh Narges Khanjani 《Enzyme and microbial technology》2013,52(6-7):352-357
Electricity generation from microbial fuel cells which treat food processing wastewater was investigated in this study. Anaerobic anode and aerobic cathode chambers were separated by a proton exchange membrane in a two-compartment MFC reactor. Buffer solutions and food industry wastewater were used as electrolytes in the anode and cathode chambers, respectively. The produced voltage and current intensity were measured using a digital multimeter. Effluents from the anode compartment were tested for COD, BOD5, NH3, P, TSS, VSS, SO4 and alkalinity. The maximum current density and power production were measured 527 mA/m2 and 230 mW/m2 in the anode area, respectively, at operation organic loading (OLR) of 0.364 g COD/l.d. At OLR of 0.182 g COD/l.d, maximum voltage and columbic efficiency production were recorded 0.475 V and 21%, respectively. Maximum removal efficiency of COD, BOD5, NH3, P, TSS, VSS, SO4 and alkalinity were 86, 79, 73, 18, 68, 62, 30 and 58%, respectively. The results indicated that catalysts and mediator-less microbial fuel cells (CAML-MFC) can be considered as a better choice for simple and complete energy conversion from the wastewater of such industries and also this could be considered as a new method to offset wastewater treatment plant operating costs. 相似文献
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Abstract: Nitrification and denitrification have traditionally been regarded as essentially separate phenomena, carried out by different bacteria in segregated areas of soil, sediments, water or reactors. However, research in the 1980s and 1990s has established that nitrifiers and denitrifiers are not as metabolically fastidious as previously thought, and strict segregation is not necessary. Moreover, some bacteria are able to convert NH4 4 and other reduced nitrogen compounds to nitrogen gas and the gaseous nitrogen oxides in combined nitrification/denitrification processes. Such organisms are of interest for wastewater treatment for two opposing reasons. Firstly, the idea of single-stage nitrogen removal has obvious attractions for system design. Secondly, N2 O is a serious pollutant, implicated in virtually all current environmental problems (e.g. acid rain, greenhouse effect, ozone depletion). 相似文献
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A bioreactor system with 30 packed gel envelopes was installed in a thermal power plant for the removal of nitrogen from ammonia-containing desulfurization wastewater. Each envelope consisted of double-sided plate gels containing Nitrosomonas europaea and Paracoccus denitrificans cells with an internal space in between for injecting an electron donor. The envelope can remove ammonia from wastewater in a single step. When the wastewater was continuously treated with the bioreactor system, it removed 95.0% of the total nitrogen in the inlet, and the total nitrogen concentration in the outlet was below 9.0 mg L−1. The maximum nitrogen removal rate was 6.0 g day−1 per square meter of the gel area. The maximum utilization efficiency of the injected ethanol for denitrification was 98.4%, and the total organic carbon concentration in the outflow was maintained at a low level. Since the bioreactor system could use the electron donor effectively, it was not necessary to use an additional aerobic tank to remove the electron donor and a settling tank to segregate the surplus sludge containing bacteria from wastewater. Our concept of using packed gel envelopes would be highly effective for constructing a simple and efficient nitrogen removal system capable of simultaneous nitrification and denitrification. 相似文献