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1
ALQAHTANI, RUBAYYI T., MARK I. NELSON und ANNETTE L. WORTHY. „A BIOLOGICAL TREATMENT OF INDUSTRIAL WASTEWATERS: CONTOIS KINETICS“. ANZIAM Journal 56, Nr. 4 (April 2015): 397–415. http://dx.doi.org/10.1017/s144618111500005x.
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This paper analyses the steady-state operation of a generalized bioreactor model that encompasses a continuous-flow bioreactor and an idealized continuous-flow membrane bioreactor as limiting cases. A biodegradation of organic materials is modelled using Contois growth kinetics. The bioreactor performance is analysed by finding the steady-state solutions of the model and determining their stability as a function of the dimensionless residence time. We show that an effective recycle parameter improves the performance of the bioreactor at moderate values of the dimensionless residence time. However, at sufficiently large values of the dimensionless residence time, the performance of the bioreactor is independent of the recycle ratio.
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Liu, Wei Ping, und Xia Fei Yin. „Continuous Flow Microbial Fuel Cell for Organic Wastewater Treatment“. Advanced Materials Research 777 (September 2013): 92–95. http://dx.doi.org/10.4028/www.scientific.net/amr.777.92.
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A continuous flow double chamber microbial fuel cell (MFC) for wastewater treatment was constructed. Anaerobic activated sludge was used as bacterial source and simulated organic wastewater was used as substrate. Effluent of anode chamber was used directly as influent of the cathode chamber. The aerobic microorganisms could degrade organic matters further. The electricity production and organic wastewater treatment of the MFC were studied. The results show that the wastewater chemical oxygen demand (COD) of the total removal rate was 74.1%~77.45%, the anode chamber in which the removal rate of COD is 32.2%~35.3%, and COD removal efficiency of aerobic biological treatment in the cathode chamber was 60.2%~66.7%. The continuous flow system could improve the removal rate further. The maximum current density of MFC was 1.56 mAm-2, the maximum output power was 24.336 mWm-2.
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Manea, Elena Elisabeta, und Costel Bumbac. „Performance Evaluation of Continuous Flow Aerobic Granular Sludge Configurations“. Revista de Chimie 70, Nr. 1 (15.02.2019): 283–85. http://dx.doi.org/10.37358/rc.19.1.6900.
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Increasing the efficiency and capacity of existing wastewater treatment plants can be carried out by using intensive biological processes. One of the currently studied biological solutions consists in using aerobic granular sludge in order to achieve both organics and nutrients removal simultaneously in one tank and with high efficiency. Aerobic granular sludge is currently used at full scale in sequential batch reactors, research for identifying the optimal solutions for continuous flow systems being carried out worldwide. The paper summarizes the results obtained for two continuous flow configurations with aerobic granular sludge, in terms of organics and nutrients removal for synthetic wastewater in laboratory conditions. Both experimental setups led to wastewater treatment efficiencies, with values ranging between 80 and 99% for COD, 85 and 99% for BOD5, 52 and 98% for NH4+ and 5 to 87% for TP.
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Bumbac, C., I. A. Ionescu, O. Tiron und V. R. Badescu. „Continuous flow aerobic granular sludge reactor for dairy wastewater treatment“. Water Science and Technology 71, Nr. 3 (05.01.2015): 440–45. http://dx.doi.org/10.2166/wst.2015.007.
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The focus of this study was to assess the treatment performance and granule progression over time within a continuous flow reactor. A continuous flow airlift reactor was seeded with aerobic granules from a laboratory scale sequencing batch reactor (SBR) and fed with dairy wastewater. Stereomicroscopic investigations showed that the granules maintained their integrity during the experimental period. Laser diffraction investigation showed proof of new granules formation with 100–500 μm diameter after only 2 weeks of operation. The treatment performances were satisfactory and more or less similar to the ones obtained from the SBR. Thus, removal efficiencies of 81–93% and 85–94% were observed for chemical oxygen demand and biological oxygen demand, respectively. The N-NH+4 was nitrified with removal efficiencies of 83–99% while the nitrate produced was simultaneously denitrified – highest nitrate concentration determined in the effluent was 4.2 mg/L. The removal efficiency of total nitrogen was between 52 and 80% depending on influent nitrogen load (39.3–76.2 mg/L). Phosphate removal efficiencies ranged between 65 and above 99% depending on the influent phosphate concentration, which varied between 11.2 and 28.3 mg/L.
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Çeçen, Ferhan. „ACTIVATED CARBON ADDITION TO ACTIVATED SLUDGE IN THE TREATMENT OF KRAFT PULP BLEACHING WASTES“. Water Science and Technology 30, Nr. 3 (01.08.1994): 183–92. http://dx.doi.org/10.2166/wst.1994.0096.
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This study examines the effect of powdered activated carbon (PAC) addition to activated sludge in the treatment of pulp bleaching effluents which contain a large amount of nonbiodegradable matter. The effect of PAC addition has been studied in both batch and continuous-flow reactors. Isotherms were developed for PAC and biomass adsorption. It was shown that substrate removal by air stripping and biosorption was negligible. The change in substrate concentration occurred mainly by biodegradation. The biological removal data obtained in batch and continuous-flow reactors were fitted to kinetic models. Both batch and continuous-flow experiments revealed that there remained a high amount of nonbiodegradable substrate as expressed by residual COD and Color436. Carbon addition to activated sludge resulted in a high decrease in substrate concentration, particularly for color. However, the results indicated that there was no noticable biological enhancement with PAC addition. The combined PAC and activated sludge process seemed to be a combination of adsorption and biodegradation.
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Bryant, Curtis W., W. A. Barkley, Michael R. Garrett und David F. Gardner. „Biological nitrification of kraft wastewater“. Water Science and Technology 35, Nr. 2-3 (01.02.1997): 147–53. http://dx.doi.org/10.2166/wst.1997.0504.
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A program of batch, continuous-flow, and field pilot tests have been conducted to measure the extent and stability of nitrification in kraft wastewater. Laboratory batch tests measured the extent and rate of ammonia removal from kraft wastewater. Controlled variables included aerated stabilization basin (ASB) location, temperature, pH, ammonia concentration, black liquor content, bicarbonate content, and presence of acclimated nitrifying bacteria. Findings were that (a) moderate wastewater temperature (22-35°C), pH near 7.3, and black liquor spill control prevented slowing of nitrification, and (b) provision of acclimated nitrifying bacteria (by appropriate recirculation methods) dramatically reduced the residence time needed for nitrification in kraft ASBs. Laboratory-scale, fixed-film, continuous-flow tests were used to investigate dynamic responses to changes in wastewater composition and flow. Results demonstrated that the nitrifying films were not ‘damaged’ by 4- or 24-hour step increases in influent ammonia, but the films could not respond quickly enough to substantially dampen out the effect on effluent quality. A pilot 4-stage rotating biological contactor (RBC) was installed at an ASB to test the nitrification of kraft wastewater under actual process variations. The results during the 11-month run were: (a) the RBC demonstrated capability to consistently and substantially reduce NH4-N concentration below 1 mg/L, (b) about one month was needed to establish effective treatment, and (c) effective treatment was sustained at a maximum hydraulic loading rate of 0.11 m3/day per m2.
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Kevbrina, M. V., Y. A. Nikolaev, D. A. Danilovich und A. Ya Vanyushina. „Aerobic biological treatment of thermophilically digested sludge“. Water Science and Technology 63, Nr. 10 (01.05.2011): 2340–45. http://dx.doi.org/10.2166/wst.2011.492.
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Aerobic biological treatment of digested sludge was studied in a continuously operated laboratory set-up. An aerated reactor was filled with thermophilically digested sludge from the Moscow wastewater treatment plant and inoculated with special activated sludge. It was then operated at the chemostat mode at different flow rates. Processes of nitrification and denitrification, as well as dephosphatation, occurred simultaneously during biological aerobic treatment of thermophilically digested sludge. Under optimal conditions, organic matter degradation was 9.6%, the concentrations of ammonium nitrogen and phosphate decreased by 89 and 83%, respectively, while COD decreased by 12%. Dewaterability of digested sludge improved significantly. The processes were found to depend on hydraulic retention time, oxygen regime, and temperature. The optimal conditions were as follows: hydraulic retention time 3–4 days, temperature 30–35 °C, dissolved oxygen levels 0.2–0.5 mg/L at continuous aeration or 0.7–1 mg/L at intermittent aeration. Based on these findings, we propose a new combined technology of wastewater sludge treatment. The technology combines two stages: anaerobic digestion followed by aerobic biological treatment of digested sludge. The proposed technology makes it possible to degrade the sludge with conversion of ∼45% volatile suspended solids to biogas, to improve nitrogen and phosphorus removal in reject water from sludge treatment units, and to achieve removal of malodorous substances after 8–9 days of anaerobic–aerobic sludge treatment.
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Kim, In-Sung, Yong-Joo Cho, Hong-Keun Choi und Eun-Ju Lee. „Biological Treatment of Processed-Leachate from Landfills by Reed (Phragmites australis)-Bed in a Continuous Flow System“. Korean Journal of Ecology 27, Nr. 6 (01.12.2004): 375–81. http://dx.doi.org/10.5141/jefb.2004.27.6.375.
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Sánchez, Jenifer Benavides, Marianna Vuono und Davide Dionisi. „Model-based comparison of sequencing batch reactors and continuous-flow activated sludge processes for biological wastewater treatment“. Computers & Chemical Engineering 144 (Januar 2021): 107127. http://dx.doi.org/10.1016/j.compchemeng.2020.107127.
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Khararjian, H. A., W. H. Callaway, P. Cardinal und J. Meany. „Intermittent Cycle Extended Aeration System (ICEAS R) for Small Wastewater Treatment Plants“. Water Science and Technology 22, Nr. 3-4 (01.03.1990): 323–30. http://dx.doi.org/10.2166/wst.1990.0218.
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Many municipalities and industrial plants with small quantities of wastewater are facing challenges with providing economical treatment strategies. They require simply designed and operated processes which give high quality effluent. One such process is the Intermittent Cycle Extended Aeration System (ICEAS R). This is a variant of the activated sludge biological process which allows continuous inflow of raw wastewater and intermittently discharged influent. It provides flow equalization, biological oxidation and sedimentation with decanting of supernatant in a single tank. The process can be operated on any cycle duration based on the required degree of treatment. Each cycle consists of aeration, sedimentation and decantation phases. The aeration phase can be operated on an oxic/anoxic mode for the purpose of nitrification/denitrification and biological phosphorus removal. To date, there are more than 100 plants worldwide and 25 within the U.S.A. that are built and operating successfully. High degrees of BOD, suspended solids and nitrogen removal are obtained with the plants. Most of the small plants require minimal operating personnel, generally one or two, for continuous operation.
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Yibo, Wen, Zhang Min und Qian Yi. „Biological Treatment of Coke-Plant Wastewater for COD and NH3-N Removal“. Water Science and Technology 23, Nr. 10-12 (01.05.1991): 1883–92. http://dx.doi.org/10.2166/wst.1991.0644.
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For removing COD and NH3-N from high-strength coke-plant wastewater, studies were conducted in a lab scale, continuous flow system, in which anaerobic, anoxic and oxic units were included. The results have shown that the effluent COD and NH3-N of A-A/O system could be less than 78 mg/L and 4.7 mg/L respectively when the influent COD and NH3-N were higher than 1200 mg/L and 240 mg/L respectively at a total HRT of 36 hrs. Moreover, the total nitrogen of wastewater was removed by 49%. It is concluded that A-A/O system is efficient for coke-plant wastewater treatment and the anaerobic process has played very important role in the system.
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Desmiarti, Reni, Yoji Morishita, Tomonari Fujisawa, Yasushi Ishiguro, Toshiro Yamada und Fusheng Li. „Characteristics of Nanoparticles in Drinking Water Treatment using Biological Activated Carbon“. MATEC Web of Conferences 156 (2018): 03039. http://dx.doi.org/10.1051/matecconf/201815603039.
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Characteristics of nanoparticles in drinking water treatment were performed using five types of biological activated carbon (BAC) columns (BAC1-BAC5) in continuous flow experiments. The BAC was created by covering granular activated carbon (GAC) with attached microorganisms from water samples taken from the Nagara River in Japan. The total running time was about 2000 h. The characteristics of the nanoparticles were investigated based on size distribution and volume distribution measured by Zetasizer Nano. Total dissolved organic carbon (DOC) and ultraviolet absorbance at 260 nm (UV260) were also studied. The important results in this study were that the detached nanoparticles in the effluent were within the size distribution ranges of 0.26~5.62 nm, 0.62~3.62 nm, 0.62~3.12 nm, 0.62~4.19 nm, and 0.62~6.50 for BAC 1, 2, 3, 4 and 5, respectively. The profile of peak size and peak number along the bed depth of the BAC columns was evaluated for better understanding the characteristics of the nanoparticles. This result is very important for improving drinking water treatment using granular activated carbon to remove microorganisms.
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Pujol, R., J. P. Canler, A. Vachon und P. Vidou. „Biological Aerated Filters: An Adapted Biological Process for Wastewater from Coastal Areas“. Water Science and Technology 25, Nr. 12 (01.06.1992): 175–84. http://dx.doi.org/10.2166/wst.1992.0349.
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SUMMARY compact facilities together with modular and environment-friendly appearance are arguments in favour of Biological Aerated Filters(B. A. F. ) in coastal areas where the amount of available land imposes strict limitations on technological choices. The operation of B. A. F. in combination with a physico-chemical process was studied using the data obtained from two wastewater treatment plants located in coastal areas (Barcares and Saint Palais/Mer, France). The main conclusions are the following.-Effluent quality in terms of COD, BOD5 S.S. proved satisfactory for organic load conditions higher than those applied when using conventional procedures.-Adaptation to organic load variations is not a basic problem for this type of coastal community,but hydraulic flow-rate control should be the main concern.-Restarting plant operation after a long shutdown only takes a few days.-Furthermore technical and economical optimisation required continuous monitoring, especially in the field of washing and aerating control. This type of management involves the use of reliable, high- performance control equipment.
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Grognard, F., und O. Bernard. „Stability analysis of a wastewater treatment plantwith saturated control“. Water Science and Technology 53, Nr. 1 (01.01.2006): 149–57. http://dx.doi.org/10.2166/wst.2006.017.
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This paper presents a saturated proportional controller that achieves depollution of wastewater in a continuous anaerobic digester. This goal is reached by defining a region of the state-space where the depollution is achieved and forcing attractivity and invariance of this region. The control variable is the dilution rate and the controlled variable is a linear combination (Sλ) of the substrates concentrations, that could be the chemical oxygen demand or the biological oxygen demand, depending on the value of λ. No measurement of the substrates concentrations in the input flow is required: the only necessary measurement is Sλ.
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El-Gohary, F. A., S. I. Abou-Elela und H. I. Aly. „Evaluation of biological technologies for wastewater treatment in the pharmaceutical industry“. Water Science and Technology 32, Nr. 11 (01.12.1995): 13–20. http://dx.doi.org/10.2166/wst.1995.0389.
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Wastewater from a pharmaceutical and chemical company provides the material of this study. The company produces drugs, diuretics, laboratory chemicals and others. The company is located 30 km north of Cairo, and discharges both industrial (1050 m3/d) and human wastewater (8400 m3/d) without treatment into a near-by evaporation pond. Reduction of pollutants in the wastewater down to permissible concentrations is necessary for the protection of ground water and the environment. Analysis of the combined wastes indicated that it is very acidic and contains high concentrations of organic compounds and total solids. Combined wastes were subjected to different treatment processes for final disposal into surface water, or reuse for irrigation purposes. Biological treatment of the combined wastes was carried out using both batch and continuous flow systems. The biological treatments included activated sludge process, fixed film reactor, and fixed film reactor followed by activated sludge process. Technical feasibility studies indicated that good quality effluent could be obtained using either extended aeration (20 hr aeration) or a fixed film reactor followed by activated sludge (11 hr detention time). Residual BOD5, COD, oil and grease concentrations in the treated effluent were complying with the National Regularity Standards. When constructional cost was considered, extended aeration was the first choice. Engineering designs of the proposed treatment options are included.
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Ferguson, John F., und Mark M. Benjamin. „Studies of Anaerobic Treatment of Sulfite Process Wastes“. Water Science and Technology 17, Nr. 1 (01.01.1985): 113–21. http://dx.doi.org/10.2166/wst.1985.0009.
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A series of laboratory studies of treatment of sulfite process wastes constitute a case study of application of high rate anaerobic biological treatment. Sulfite evaporator condensate (SEC) was evaluated in batch and continuous flow studies to find the efficiency of treatment that was possible and the conditions suitable for treatment. The role of sulfur and neutralization in the process were especially significant. Caustic extraction stage bleaching wastes (CE) were also studied for their use in neutralizing the evaporator condensate. Toxicity effects requiring dilution were found, but both CE and SEC can be treated, removing most of the BOD in a high rate process at detention times believed suitable for commercial application.
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Chithra Devi, Rengaraj, Nirmaladevi D. Shrinithivihahshini und Rajendran Viji. „Study on the efficiency of continuous flow-based constructed wetland system for grey water treatment“. International Journal of Advances in Scientific Research 3, Nr. 5 (05.06.2017): 52. http://dx.doi.org/10.7439/ijasr.v3i5.4198.
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Water is inevitable for our life. Due to the population growth, there is a tremendous pressure on the existing fresh water resources such as surface water and ground water. Increasing water demand and improper usage of potable water lead to scarcity of fresh water resources. Globally, treating grey water is a real constraint to minimize the problem of water scarcity. The continuous flow-based constructed wetland system for grey water treatment is a technique for reusing the domestic grey water and it is a low-cost method. The current study was aimed to evolve a suitable user-friendly treatment system for handling the household grey water. In the present study, grey water has been collected from the Bharathidasan University and it has been treated with biofiltration and rhizhodegradation techniques using continuous flow-based constructed wetland system. The system has been found as more effective for treating the Physico-chemical parameters such as suspended solids, pH, electrical conductivity, TS, TDS, DO, BOD, COD, TOC, CO3, HCO3, SO4, NO3, PO4, Ca, Mg, Na, K, total hardness, calcium hardness, chloride, and total alkalinity. The results reported the reduction in the biological oxygen demand (89%), chemical oxygen demand (81%), DO (95%), carbonate (100%), sodium (65%), and potassium (85%).It also examined the benefits and risks associated with the results in the reuse of domestic grey water for the purpose of vegetable gardening, irrigation, and toilet flushing. Consequently, this biofiltration method is natural, simple, and low cost-effective treatment in a holistic manner.
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Sipaúba-Tavares, LH, CST Guariglia und FMS Braga. „Effects of rainfall on water quality in six sequentially disposed fishponds with continuous water flow“. Brazilian Journal of Biology 67, Nr. 4 (November 2007): 643–49. http://dx.doi.org/10.1590/s1519-69842007000400008.
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An investigation was carried out during the rainy period in six semi-intensive production fish ponds in which water flowed from one pond to another without undergoing any treatment. Eight sampling sites were assigned at pond outlets during the rainy period (December-February). Lowest and highest physical and chemical parameters of water occurred in pond P1 (a site near the springs) and in pond P4 (a critical site that received allochthonous material from the other ponds and also from frog culture ponds), respectively. Pond sequential layout caused concentration of nutrients, chlorophyll-a and conductivity. Seasonal rains increased the water flow in the ponds and, consequently, silted more particles and other dissolved material from one fish pond to another. Silting increased limnological variables from P3 to P6. Although results suggest that during the period under analysis, rainfall affected positively the ponds' water quality and since the analyzed systems have been aligned in a sequential layout with constant water flow from fish ponds and parallel tanks without any previous treatment, care has to be taken so that an increase in rain-induced water flow does not have a contrary effect in the fish ponds investigated.
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Chong, Nyuk-Min. „BIOLOGICAL TREATABILITY OF AMINE LADEN REFINERY WASTEWATER“. Water Science and Technology 30, Nr. 3 (01.08.1994): 21–28. http://dx.doi.org/10.2166/wst.1994.0054.
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Mono- and Di- hydroxyl amines are used in the desulfuration processes for refined petroleum products. The refinery wastewater treatment plant may be shocked by amine laden wastewater periodically, bringing operation difficulties to the biological treatment units. Data on the treatability, shock load behaviour and on long term system stability of biological treatment of amines are therefore required. Shake-flask test results showed that pure diethanol amine and diisopropanol amines have characteristics of persistent compounds. Each of the two compounds has a prolonged lag time when first inoculated with indigenous activated sludge. Acclimated activated sludge in a continuous flow reactor treated a feed of ethanol amine with a 93 percent COD removal and a 98 percent nitrification, but the system was unstable because amine caused a bulking sludge. By physical retention of the activated sludge, 550 mg/l influent COD of amines was treated to m1 average 50 mg/l effluent COD. Sludge yield was approximately 0.26 mg MLSS per mg COD. The activated sludge system withstood a chm1ge of feed to a real refinery wastewater laden with the; amine. A mean cell residence time above five (5) days should be maintained for safe treatment of; amine.
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Taseli, Basak (Kilic), und C. F. Gokcay. „Biological Treatment of Paper Pulping Effluents by Using a Fungal Reactor“. Water Science and Technology 40, Nr. 11-12 (01.12.1999): 93–99. http://dx.doi.org/10.2166/wst.1999.0699.
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Pulp and paper plants are amongst the most polluter industries in this country and elsewhere. Most of the organic halides (AOX) and colour from pulp bleaching units are discharged to the receiving basins without being fully treated. A fungus, which is able to affect over 50% AOX and colour removals from soft-wood bleachery effluents within two days contact time, have been isolated in this laboratory. Optimum condition for dechlorination by this fungus in batch tests was determined as pH 5.5 and 25 °C. The low agitation speeds required by the fungus indicated its tendency towards immobilisation on a solid substrate. Glass wool was chosen as a suitable immobilising matrix to be used in the continuous experiments. An up-flow column was packed with glass wool and operated successfully for over one and half years with AOX removals around 70% in 7-8 hours contact time. Fungal dehalogenation required very low supplemental carbon and no DO. The fungal reactor was also effective in dechlorinating polychlorinated aromatics, e.g. PCP, though dehalogenation ability decreased considerably with the chlorinated aliphatics. High PCP concentrations presumably toxified the fungus, even at short exposures, thereby irreversibly damaging the column reactor.
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He, Can, Jianbing Wang, Heng Xu, Xiangyu Ji, Weiyi Wang und Xieyang Xu. „Treatment of Bio-Treated Coking Wastewater by Catalytic Ozonation with Semi-Batch and Continuous Flow Reactors“. Water 12, Nr. 9 (10.09.2020): 2532. http://dx.doi.org/10.3390/w12092532.
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In this work, the treatment of bio-treated coking wastewater (BCW) by catalytic ozonation was conducted in semi-batch and continuous flow reactors. The kinetics of chemical oxygen demand (COD) removal were analyzed using BCWs from five coking plants. An integral reactor with catalytic ozonation stacked by ozone absorption (IR) was developed, and its efficiency was studied. The catalyst of MnxCe1-xO2/γ-Al2O3 was efficient in the catalytic ozonation process for the treatment of various BCWs. The chemical oxygen demand (COD) removal efficiencies after 120 min reaction were 64–74%. The overall apparent reaction rate constants were 0.0101–0.0117 min−1, which has no obvious relationship with the initial COD of BCW and pre-treatment biological process. The IR demonstrated the highest efficiency due to the enhancement of mass transfer and the utilization efficiency of ozone. Bypass internal circulation can further improve the reactor efficiency. The optimal results were obtained with the ozone absorption section accounting for 19% of the valid water depth in the reactor and 250% of circulation flow ratio. The long-term and full-scale application of the novel reactor in a continuous mode indicated stable removal of COD and polycyclic aromatic hydrocarbons (PAHs). The results showed that the system of IR is a promising reactor type for tertiary treatment of coking wastewater by catalytic ozonation.
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Truong, Canh Thanh. „TREATMENT OF OF PIGGERY WASTEWATER BY BIOPROCESS TECHNOLOGY - UPFLOW SLUDGE BLANKET FILTER (USBF)“. Science and Technology Development Journal 13, Nr. 1 (30.03.2010): 48–58. http://dx.doi.org/10.32508/stdj.v13i1.2081.
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This paper describes a research to use an innovative combined biological process, upflow sludge blanket filter (USBF), that rapidly and economically remove BOD, nitrogen and phosphorus from piggery wastewater. The USBF design is a continuous flow system incorporating the aeration zone, clarifier and anoxic zone into a single tank. The research showed a result of 97%, 80%, 94%, 90% and 85% for COD, BOD5, SS, nitrogen and phosphorus removal, respectively. This is concluded that USBF can be used as a simple and economic method to treat pigerry wastewater.
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Bortone, G., R. Saltarelli, V. Alonso, R. Sorm, J. Wanner und A. Tilche. „Biological anoxic phosphorus removal - the dephanox process“. Water Science and Technology 34, Nr. 1-2 (01.07.1996): 119–28. http://dx.doi.org/10.2166/wst.1996.0363.
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Simultaneous enhanced biological phosphate uptake and biological denitrification under anoxic conditions were investigated in a modified lab-scale nutrient removal activated sludge system (DEPHANOX). The aim of the experiments was to find whether it can be technologically convenient to use the capability of poly-P bacteria of taking up phosphate under anoxic condition by utilizing nitrate as electron acceptor. An experimental comparison of removal efficiencies with a more conventional treatment flow scheme (JHB), using low influent TKN/COD ratio, was also carried out. Phosphate uptake in anoxic condition was compared to that in oxic environment in batch tests. PHB anoxic and oxic degradation was evaluated by respirometric tests. Results of the long-term operation of continuous-flow lab-scale system as well as results of batch tests showed that the anoxic phosphate uptake with simultaneous denitrification after a previous anaerobic substrate uptake could significantly reduce the extent of competition for organic substrate between poly-P bacteria and denitrifiers. A side-stream nitrification in fixed-film reactor reduced the losses of organic carbon by oxidation and stabilized the slow-growing population of nitrifiers in the system.
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Nogueira, E. W., F. M. Licona, L. A. G. Godoi, G. Brucha und M. H. R. Z. Damianovic. „Biological treatment removal of rare earth elements and yttrium (REY) and metals from actual acid mine drainage“. Water Science and Technology 80, Nr. 8 (15.10.2019): 1485–93. http://dx.doi.org/10.2166/wst.2019.398.
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Abstract Actual acid mine drainage (AMD) containing a high concentration of sulfate (∼1,000 mg·L−1), dissolved metals, uranium, rare earth elements and yttrium (REY) was treated using a down-flow fixed-structured bed biological reactor (DFSBR). The reactor was operated in a continuous flow mode for 175 days and the temperature was maintained at 30 °C. The synthetic AMD was gradually replaced by the actual AMD in 20, 50 and 75% of the total medium volume. Sugarcane vinasse was used as the electron donor and the influent pH of the reactor was decreased from 6.9 to 4.6 until the system collapsed. REY elements and transition metals were removed from the actual AMD and precipitated in the down-flow fixed-structured bed reactor. Sulfate reduction achieved 67 ± 22% in Phase II and chemical oxygen demand (COD) removal was above 56% in Phases I and II. Removal of La, Ce, Pr, Nd, Sm and Y was higher than 70% in both Phases II and III while Fe, Al, Si and Mn were removed with efficiencies of 79, 67, 48 and 25%, respectively. The results highlighted the potential use of DFSBR in the treatment of AMD, providing possibilities for simultaneous sulfate reduction and metal and REY recovery in a single unit.
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Nenov, Valentin. „TSS/BOD removal efficiency and cost comparison of chemical and biological wastewater treatment“. Water Science and Technology 32, Nr. 7 (01.10.1995): 207–14. http://dx.doi.org/10.2166/wst.1995.0234.
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Based on standard settling column tests, Jar tests and continuous activated sludge laboratory experiments as well as combination of these processes implemented for a treatment of municipal wastewater with a composition typical for the influent water of Ravda Municipal Wastewater Treatment (MWWT) plant, the removal efficiency obtained in respect of the total suspended solids (TSS) and the biochemical oxygen demand (BOD) was evaluated. The laboratory experiments confirmed the high efficiency of the chemically enhanced mechanical treatment (CEMT) towards TSS and BOD/COD removal. The data obtained show that low dose chemical treatment in a large range of surface flow rate of precipitation provides a reduction of TSS and BOD/COD larger than 60% and 50%, respectively. Regarding Ravda WWTP as a typical case for the Black Sea coast it was proved that CEMT is an attractive alternative for retrofitting the existing plants based on the activated sludge process as a secondary treatment process. CEMT upgrading can be done at much lower cost (practically only O&M treatment expenditure is required) compared with an eventual biological step extension.
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Aziz, Faissal, Mounir El Achaby, Amina Lissaneddine, Khalid Aziz, Naaila Ouazzani, Rachid Mamouni und Laila Mandi. „Composites with alginate beads: A novel design of nano-adsorbents impregnation for large-scale continuous flow wastewater treatment pilots“. Saudi Journal of Biological Sciences 27, Nr. 10 (Oktober 2020): 2499–508. http://dx.doi.org/10.1016/j.sjbs.2019.11.019.
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Mohammed, Noor Abdul Ameer, Abeer I. Alwared und Mohammed S. Salman. „The Continuous Decolorization of Reactive Yellow Dye using Advanced Oxidation Reactors“. Iraqi Journal of Chemical and Petroleum Engineering 21, Nr. 2 (30.06.2020): 1–6. http://dx.doi.org/10.31699/ijcpe.2020.2.1.
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The reactive yellow azo dye (λmax = 420 nm) is widely utilized for textile coloring due to its low-cost stability and tolerance properties. Treatment of dye-containing wastewater by traditional methods is usually inadequate because of its resistance to biological and chemical degradation. From this research, the continuous reactor of an advanced oxidation method supported the use of H2O2/TiO2/UV to remove the coloration of the reactive yellow dye from the discharge. At constant best conditions obtained from the batch reactor tests pH=7, H2O2 dosage = 400 mg/l and TiO2=25mg/l , the aqueous solutions were tested in the continuous reactor at different dye concentration and different flow rates . The maximum removal efficiency was found to be 91.552% obtained at the flow rate 5 l/h, also the results of decomposition information proved that method was pseudo-first-order kinetics.
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ZOU, Haiming, und Xiwu LU. „AN INNOVATIVE CONTINUOUS FLOW BNR-IC PROCESS FOR NUTRIENTS REMOVAL AND PHOSPHORUS RECOVERY FROM SYNTHETIC AND REAL DOMESTIC WASTEWATER“. JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 24, Nr. 2 (07.06.2016): 116–23. http://dx.doi.org/10.3846/16486897.2015.1113180.
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An innovative continuous flow process linking biological nutrients removal (BNR) with induced crystallization (IC) was used to remove nutrients and recover phosphorus (P) from synthetic and real domestic wastewater. The results showed that a good nutrients removal performance was found regardless of feeding solutions. P recovery efficiency from synthetic wastewater was 70.2% slightly less than that from real domestic sewage (74.2%). Importantly, P recovery can effectively enhance the subsequent biological P removal. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis displayed an obvious shift in microbial community structure when switching feeding synthetic solution to real wastewater. A total of 13 bands were detected in sludge samples using synthetic and real domestic sewage, affiliated with 8 phyla or classes domain Bacteria (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Flavobacteria, Actinobacteria, Sphingobacteria, Epsilonproteobacteria and Chlorobia). The results obtained here suggest that the continuous flow BNR-IC process is feasible for nutrients removal and P recovery from domestic sewage and is a promising technology for wastewater treatment combined with recycling of P elements.
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Tracy, Mark L., Sue E. Littlefield und Gregory Möller. „Continuous Flow Vapor Generation for Inductively Coupled Argon Plasma Spectrometric Analysis. Part 2. Arsenic“. Journal of AOAC INTERNATIONAL 74, Nr. 3 (01.05.1991): 516–21. http://dx.doi.org/10.1093/jaoac/74.3.516.
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Abstract Total arsenic Is determined by Inductively coupled plasma atomic emission using hydride vapor generation. A 1 g sample is wet ashed in a 16 X 150 mm 10 mL volumetric test tube on a programmed heating block with nitric, sulfuric, and perchloric acids at up to 310 °C. After treatment with hydrochloric acid and potassium iodide, arsenic Is reduced by sodium borohydride to arsine In a simplified continuous flow manifold. A standard pneumatic nebulizer effects the gasliquid separation of AsH3, which is quantified by ICP atomic emission at 193.756 nm. The instrument detection limit for the method has been determined to be 0.4 μg/L. For a 10:1 dilution of a nominal 1 g sample, the detection limit is 4 μg/kg and the linear range Is up to 4 mg/kg. Recoveries from 3 matrixes were 99-104%, with a typical RSD of 2%. The method has demonstrated statistical control for samples of biological interest and is especially well suited to analysis of small samples.
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Bhattarai, Kiran K., Chongrak Polprasert und Bindu N. Lohani. „Models for Aquacultural Treatment of Septage“. Water Science and Technology 18, Nr. 7-8 (01.07.1986): 103–12. http://dx.doi.org/10.2166/wst.1986.0280.
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The research programme on aquacultural treatment of nightsoil has been conducted at the Asian Institute of Technology (AIT) for about 10 years. This paper emphasizes only the research scheme in which nightsoil is fed directly into single-stage, non-flow-through ponds for the production of algae and fish Tilapia (Qreochromisniloticus). The culture of herbivorous fish such as Tilapia in the same pond to graze on the algae is practical, in order to produce the fish protein biomass which is easily harvestable for animal (or human) food. Dynamic and empirical models describing the performance of nightsoil-fed fish ponds were developed to simulate the temporal changes of various physico-chemical and biological parameters including dissolved oxygen, carbon dioxide, bacteria, algae, and fish growth. These models were based on the basic mechanisms and phenomena occurring in the ponds, and the simulated results calculated from the Continuous System Modelling Programme (CSMP) computer package available at the AIT Regional Computer Center.
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Rosa-Masegosa, Aurora, Barbara Muñoz-Palazon, Alejandro Gonzalez-Martinez, Massimiliano Fenice, Susanna Gorrasi und Jesus Gonzalez-Lopez. „New Advances in Aerobic Granular Sludge Technology Using Continuous Flow Reactors: Engineering and Microbiological Aspects“. Water 13, Nr. 13 (29.06.2021): 1792. http://dx.doi.org/10.3390/w13131792.
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Aerobic granular sludge (AGS) comprises an aggregation of microbial cells in a tridimensional matrix, which is able to remove carbon, nitrogen and phosphorous as well as other pollutants in a single bioreactor under the same operational conditions. During the past decades, the feasibility of implementing AGS in wastewater treatment plants (WWTPs) for treating sewage using fundamentally sequential batch reactors (SBRs) has been studied. However, granular sludge technology using SBRs has several disadvantages. For instance, it can present certain drawbacks for the treatment of high flow rates; furthermore, the quantity of retained biomass is limited by volume exchange. Therefore, the development of continuous flow reactors (CFRs) has come to be regarded as a more competitive option. This is why numerous investigations have been undertaken in recent years in search of different designs of CFR systems that would enable the effective treatment of urban and industrial wastewater, keeping the stability of granular biomass. However, despite these efforts, satisfactory results have yet to be achieved. Consequently, it remains necessary to carry out new technical approaches that would provide more effective and efficient AGS-CFR systems. In particular, it is imperative to develop continuous flow granular systems that can both retain granular biomass and efficiently treat wastewater, obviously with low construction, maintenance and exploitation cost. In this review, we collect the most recent information on different technological approaches aimed at establishing AGS-CFR systems, making possible their upscaling to real plant conditions. We discuss the advantages and disadvantages of these proposals and suggest future trends in the application of aerobic granular systems. Accordingly, we analyze the most significant technical and biological implications of this innovative technology.
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Pandoli, Omar, Fatima Ventura Pereira-Meirelles, Eric Monteiro Lobo Lobo Luz, Aline Assumpção, Raquel dos Santos Martins, Tommaso del Rosso und Khosrow Ghavami. „Synthesis of Silver Nanoparticles with Potential Antifungical Activity for Bamboo Treatment“. Key Engineering Materials 668 (Oktober 2015): 86–91. http://dx.doi.org/10.4028/www.scientific.net/kem.668.86.
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To increase the durability of bamboo it is important to find an easy method to fill the micro and meso structure of the biological matrix using a nanostructural material with an anti-fungical activity. A colloidal solution of silver nanoparticle (Ag-NPs) is a dispersion of metal nanoparticle in water with a diameter between 5-100 nm. Even if the biological mechanism is not completly understood yet, Ag-NPs show a satisfactory bactericidal and antifungical activity. We present a simple and rapid production of Ag-NPs made by a sol-gel synthesis in flow mode by means of microreactor tecnology through a chemical reduction of AgNO3 with NaBH4 in presence of two different organic ligands: sodium/potassium tartrate and trisodium citrate. The synthesis of Ag-NPs in continuous flow compared to the batch technique allowed to reduce the time of synthesis, facilitating the reproducibility of the process and consequently obtaining NPs with more uniform physical and chemical characteristics. The microorganisms of the genus Aspergillus were used for the microbiological tests. The effect of different Ag-NPs on microbial growth was observed daily. In particular, it was shown that the response of the fungus is inversely proportional to the size of the nanoparticles, cell growth is disrupt depending on the proportion between silver and organic ligand and microbialstatic effect, especially in relation to sporulation stage was also observed.
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Calzavara, Diego, Davide Ferraro, Lucio Litti, Greshia Cappozzo, Giampaolo Mistura, Moreno Meneghetti und Matteo Pierno. „Single File Flow of Biomimetic Beads for Continuous SERS Recording in a Microfluidic Device“. Advances in Condensed Matter Physics 2018 (20.06.2018): 1–9. http://dx.doi.org/10.1155/2018/2849175.
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A major challenge in cancer treatment is the quantification of biomarkers associated with a specific cancer type. Important biomarkers are the circulating tumor cells (CTCs) detached from the main cancer and circulating in the blood. CTCs are very rare and their identification is still an issue. Although CTCs quantification can be estimated by using fluorescent markers, all the fluorescence techniques are strongly limited by the number of emissions (therefore markers) that can be discriminated with one exciting line, by their bleaching characteristics, and by the intrinsic autofluorescence of biological samples. An emerging technique that can overcome these limitations is Surface Enhanced Raman Scattering (SERS). Signals of vibrational origin with intensity similar to those of fluorescence, but narrower bandwidths, can be easily discriminated even by exciting with a single laser line. We recently showed the benefit of this method with cells fixed on a surface. However, this approach is too demanding to be applied in clinical routine. To effectively increase the throughput of the SERS analysis, microfluidics represents a promising tool. We report two different hydrodynamic strategies, based on device geometry and liquids viscosity, to successfully combine a microfluidic design with SERS.
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Gavasci, Renato, Agostina Chiavola und Massimo Spizzirri. „Technical-economical analysis of selected decentralized technologies for municipal wastewater treatment in the city of Rome“. Water Science and Technology 62, Nr. 6 (01.09.2010): 1371–78. http://dx.doi.org/10.2166/wst.2010.337.
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Several wastewater treatment technologies were evaluated as alternative systems to the more traditional centralized continuous flow system to serve decentralized areas of the city of Rome (Italy). For instance, the following technologies were selected: (1) Constructed wetlands, (2) Membrane Biological Reactor, (3) Deep Shaft, (4) Sequencing Batch Reactor, and (5) Combined Filtration and UV-disinfection. Such systems were distinguished based on the limits they are potentially capable of accomplishing on the effluent. Consequently, the SBR and DS were grouped together for their capability to comply with the standards for the discharge into surface waters (according to the Italian D.Lgs. 152/06, Table 1, All. 5), whereas the MBR and tertiary system (Filtration + UVc-disinfection) were considered together as they should be able to allow effluent discharge into soil (according to the Italian D.Lgs. 152/06, Table 4, All. 5) and/or reuse (according to the Italian D.M. 185/03). Both groups of technologies were evaluated in comparison with the more common continuous flow treatment sequence consisting of a biological activated sludge tank followed by the secondary settlement, with final chlorination. CWs were studied separately as a solution for decentralized urban areas with limited population. After the analysis of the main technical features, an economical estimate was carried out taking into account the investment, operation and maintenance costs as a function of the plant's capacity. The analysis was based on real data provided by the Company who manages the entire water system of the City of Rome (Acea Ato 2 S.p.A.). A preliminary design of the treatment plants using some of the selected technologies was finally carried out.
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Hu, Kun, Zhen Zhong Li, Yong Guo und Wei Xing Huang. „Operating Conditions and Kinetics of Wastewater Treatment in a Three-Phase Biological Fluidized Bed Reactor“. Advanced Materials Research 396-398 (November 2011): 1989–94. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.1989.
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Systematic experiments were carried out with synthetic wastewater in order to investigate the operating conditions and kinetics of wastewater treatment in a three-phase biological fluidized bed reactor. It is found that with the COD loading rate changed stepwise from 3.5 to 11.2 kg COD/m3•d, the reactor can rapidly restore from each impact of COD load and maintain the removal rate for COD at 85% or above, presenting a high flexibility for the variation of organic loading rate (OLR) in the influent. While the operating OLR keeps constant, the increase of influent COD and NH3-N concentrations will be followed by the correspondingly increased removal rates, so that the COD and NH3-N concentrations in the effluent keep nearly constant. The batched experiments under different air supply conditions show that there exists an optimal air flow rate at which the most effective treatment can be achieved. Finally, a kinetics model of the continuous treatment process was derived based on mass balance and Monod equations, and the kinetic constants were determined by the experimental data at steady operating OLR.
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Sarria, V., S. Parra, M. Invernizzi, P. Péringer und C. Pulgarin. „Photochemical-biological treatment of a real industrial biorecalcitrant wastewater containing 5-amino-6-methyl-2-benzimidazolone“. Water Science and Technology 44, Nr. 5 (01.09.2001): 93–101. http://dx.doi.org/10.2166/wst.2001.0259.
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5-amino-6-methyl-2-benzimidazolone (AMBI), used in the manufacture of dyes, was characterised as a biorecalcitrant compound by means of different biodegradability tests. In order to enhance the biodegradability of this important pollutant, the application of Advanced Oxidation Process (AOPs) as a pre-treatment was explored. Some experiments were addressed to find the most efficient AOP. The systems H2O2/hv, TiO2/H2O2/hv, Fe3+/hv, Fe3+/H2O2 and Fe3+/H2O2/hv were compared. The photo-Fenton system was the most efficient and the optimal conditions (AMBI, Fe3+, H2O2 concentrations) for the degradation of AMBI were found. During the photo-Fenton degradation, experiments were also made to obtain information concerning the evolution of: (a) organic carbon and initial compound concentration; (b) the oxidation state; (c) the toxicity; (d) the biodegradability; and (e) the chemical nature of the intermediates. These analyses show that the solution resulting from the treatment of AMBI is biologically compatible and complete mineralisation can be performed by biological means. A combined photochemical (Fenton) and biological flow reactor for the degradation of AMBI was successfully operated in continuous mode at laboratory scale. 100% of the initial concentration of AMBI and 80.3% of Dissolved Organic Carbon (DOC) were removed in 3.5 hours of total residence time. Finally, some field experiments under direct sunlight carried out at the Plataforma Solar de Almeria, Spain, demonstrated that this solar catalytic system is an effective treatment for this kind of industrial wastewater.
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Jethwa, Dr Kruti B. „A Review on Design Basis for Constructed Wetlands for Wastewater Treatment“. International Journal for Research in Applied Science and Engineering Technology 9, Nr. VIII (15.08.2021): 373–77. http://dx.doi.org/10.22214/ijraset.2021.37163.
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Since last few years Constructed Wetlands (CWs) are being used to treat secondary or tertiary municipal or domestic wastewater effluents have been recognized as an effective means of “green technology” for wastewater treatment. Constructed wetlands (CWs) provide a natural way for simple, inexpensive, and robust wastewater treatment. The idea of natural management systems is the restoration of disturbed ecosystems and their sustainability for remuneration to nature. The Constructed wetlands (CWs) are designed to copy natural wetland systems, utilizing wetland plants, soil and associated microorganisms using various biological, physicochemical processes to remove unwanted constituents from wastewater effluents. This review paper studies various types of constructed wetlands, i.e., surface or subsurface, vertical or horizontal flow and their type of operation, i.e., continuous, batch or intermittent flow, loading rate, selection of plants and wastewater characteristics that affect the treatment efficiency. The design models with their suitability for various parameters and operational conditions such as Darcy’s equation, Kadlec and Knight Model (K-C* model), Arrhenius equation, and population equivalent calculation have been discussed. Lastly, future research requirements have been considered.
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Zhao, Shuang, und Cui Ping Wang. „Simultaneous COD and Nitrogen Removal in Up-Flow Microaerobic-Oxic (M/O) Process for Domestic Wastewater Treatment“. Advanced Materials Research 838-841 (November 2013): 2739–44. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.2739.
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A novel process for improving the energy use and treatment efficiency of the biological nitrogen removal process, up-flow microaerobic-oxic (M/O) process which is composed of up-flow micro-aerobic and aeration was proposed based on a laboratory scale for domestic wastewater treatment, the dissolved oxygen (DO) in up-flow micro-aerobic was in the range of (0~0.5) mg/L. The M/O process performance under different hydraulic retention time (HRT) and Internal return ratio (r) was investigated. Under the optimal conditions, the average removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and ammonium nitrogen (NH4+-N) were 89.1%, 64.1%, and 96.6 % with effluent concentrations of COD, TN and NH4+-N less than 50,15 and 8mg/L, respectively. The distribution of sludge particles diameter and microbial activity of activated sludge were also measured, the mean particle diameter was in the range of 180~250μm and the SOURT was 13.11 mgO2/(gMLVSSh). Up-flow micro-aerobic (M/O) reactor has the advantages of more stable performance and better resistance to the load shock than the conventional A/O process within continuous running period of 130 days.
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Woolard, C. R. „The advantages of periodically operated biofilm reactors for the treatment of highly variable wastewater“. Water Science and Technology 35, Nr. 1 (01.01.1997): 199–206. http://dx.doi.org/10.2166/wst.1997.0046.
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Many wastes generated by industry, at hazardous wastes sites and at landfill experience shock loads of inhibitory organic compounds which can upset biological treatment systems. Biofilm reactors can be used to treat these wastes. However, the continuous flow mode operation normally used results in biofilm stratification and uneven biomass distribution that limits the ability of biofilm processes to treat shock loads. Periodic operation of biofilm reactors is advantageous because even biomass distribution can be obtained. In addition, data from membrane sequencing batch biofilm reactors indicates that periodic operation imposes regular variations in substrate concentration on the biofilm. As a result, organisms throughout the film achieve maximum growth rates which cause physiological adaptations that can improve biofilm response to shock loads.
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Odendaal, P. E. „Wastewater Reclamation Technologies and Monitoring Techniques“. Water Science and Technology 24, Nr. 9 (01.11.1991): 173–84. http://dx.doi.org/10.2166/wst.1991.0247.
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The paper deals with technologies for the direct reuse of treated municipal wastewater. The choice of reclamation technologies is determined by the quality of the wastewater, quality criteria for the reuse applications, reliability, operational considerations and the extent of control over the total treatment sequence. Catchment quality control as well as flow and quality equalisation should be regarded as first steps and an integral part of reclamation technology. Biological treatment is of primary importance, and special attention is given to the benefits for reclamation of activated sludge processes with high sludge retention times, and to biological nitrogen and phosphorus removal. Further unit processes discussed are chemical coagulation and flocculation, solids separation, disinfection, activated carbon, reverse osmosis, stabilisation and sludge management. In discussing monitoring techniques, attention is given to instrumentation, analogue and digital transmission, flow measurement, continuous measurement of selected parameters, sampling, maintenance, visual observation, and biomonitoring. In the conclusion, examples are given of various applications of using secondary effluent with little or no tertiary treatment, and the point made that considerable impact on the conservation of water supplies can be made without resorting to complicated and expensive technology.
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Rathnaweera, S. S., B. Rusten, L. D. Manamperuma, S. Wang und B. Helland. „Innovative, compact and energy-efficient biofilm process for nutrient removal from wastewater“. Water Science and Technology 81, Nr. 9 (01.05.2020): 1941–50. http://dx.doi.org/10.2166/wst.2020.245.
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Abstract Rapid population growth, industrial development and stringent demand for treatment of wastewater require developing and emerging economies to upgrade existing wastewater treatment plants (WWTPs) or planning new WWTPs. In the context of unavailability or unaffordability of land and resources for infrastructure expansion, low cost, small footprint, less energy consumption and product reuse are some of the major factors to be considered when either upgrading or designing new WWTPs in developing and emerging economies. Although the transition from activated sludge to biofilm processes has partly solved these challenges, there are innovations that can make the processes even more compact and more efficient. Newly developed CFIC (continuous flow intermittent cleaning) process is the next generation moving bed biological wastewater treatment system and is an example for addressing these issues. The CFIC pilot studies showed promising performance for biological chemical oxygen demand and nitrogen removal as well as particle separation facilitating wastewater reuse.
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Haghighi-Podeh, M. R., und G. Siyahati-Ardakani. „Fate and toxic effects of cyanide on aerobic treatment systems“. Water Science and Technology 42, Nr. 3-4 (01.08.2000): 125–29. http://dx.doi.org/10.2166/wst.2000.0368.
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Many industries discharge significant quantities of cyanide into the environment. Removal of cyanide is a vital task of increasing importance. Currently, the chemical methods of treating cyanide wastewater are used worldwide. The high cost, disposal problems and toxic by-products formation of chemical methods for treating cyanide wastewater has opened the door for more investigation of new methods. This paper evaluates the fate and toxic effects of cyanide on aerobic treatment systems. Both batch and continuous flow experiments were performed. The results indicate that the aerobic biological treatment of cyanide wastewater is an effective technology, which offers many advantages over chemical treatment methods. The microbiological experimental results show that among the microorganisms present in the culture, oscillatoria, philodina, carchesium, pseudomonas and bacillus bacteria were resistant to cyanide and capable of biodegrading it. The results of this study indicate that biodegradation and sorption of cyanide are the most important and least important removal mechanisms, respectively.
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Bewtra, J. K., N. Biswas, W. D. Henderson und J. A. Nicell. „Recent Advances in Treatment of Selected Hazardous Wastes“. Water Quality Research Journal 30, Nr. 1 (01.02.1995): 115–26. http://dx.doi.org/10.2166/wqrj.1995.016.
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Abstract Horseradish peroxidase, once activated by hydrogen peroxide, initiates the oxidation of a wide variety of aromatic compounds. The products of this reaction undergo a non-enzymatic polymerization to form water insoluble aggregates which are easily separated from solution. This process shows great promise for removing aromatic compounds from industrial wastewaters which are not efficiently removed through conventional treatment methods. The capability of solubilized horseradish peroxidase in catalyzing the precipitation of phenols from solution in batch reactors is discussed. Studies have been conducted on the biological sulfate reduction process to remove metals from synthetic and actual industrial wastewaters. Under anaerobic conditions, bacteria of the genera Desulfovibrio and Desulfotomaculum produce hydrogen sulfide which reacts with metals to form metal sulfide precipitates. An anaerobic upflow fixed-film reactor with continuous flow was used to treat actual wastewater from a plating plant supplemented with lactate. The results indicate that soluble metals can be precipitated at efficiencies of up to 99%. The rates of organic conversion, sulfate reduction and metal removal have been found to be dependent on the hydraulic retention time.
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Nowak, Agata, Robert Mazur, Ewa Panek und Joanna Chmist. „Model Studies on the Effectiveness of MBBR Reactors for the Restoration of Small Water Reservoirs“. E3S Web of Conferences 30 (2018): 02004. http://dx.doi.org/10.1051/e3sconf/20183002004.
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The authors present the Moving Bed Biofilm Reactor (MBBR) model with a quasi-continuous flow for small water reservoir restoration, characterized by high concentrations of organic pollutants. To determine the efficiency of wastewater treatment the laboratory analysis of physic-chemical parameters were conducted for the model on a semi-technical scale of 1:3. Wastewater treatment process was carried out in 24 h for 1 m3 for raw sewage. The startup period was 2 weeks for all biofilters (biological beds). Approximately 50% reduction in COD and BOD5 was obtained on average for the studied bioreactors. Significant improvements were achieved in theclarity of the treated wastewater, with the reduction of suspension by 60%. The oxygen profile has improved significantly in 7 to 9 hours of the process, and a diametric reduction in the oxidative reduction potential was recorded. A preliminary model of biological treatment effectiveness was determined based on the conducted studies. In final stages, the operation mode was set in real conditions of polluted water reservoirs.
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Bortone, Giuseppe, Sabrina Gemelli, Andrea Tilche, Roberto Bianchi und Giovanni Bergna. „A new approach to the evaluation of biological treatability of industrial wastewater for the implementation of the “waste design” concept“. Water Science and Technology 36, Nr. 2-3 (01.07.1997): 81–90. http://dx.doi.org/10.2166/wst.1997.0488.
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An intrinsic characteristic of the Italian industrial production system is the presence of several industrial districts with a prevalent manufacturing typology, in which several small and medium enterprises dealing with the same or similar products are concentrated in a small territory. An important textile district is localized in Como area, north of Italy. In many cases, industrial districts are served by large treatment plants that receive the majority of the pollution loading from several small and medium enterprises that do not have internal treatment facilities. The treatment fee is determined by regional regulations; commonly, the single wastewater stream connected to the sewer is billed by the sewer manager to the source industry on the basis of the flow rate and of a complex formula that takes into account a series of parameters. This method is unable to properly evaluate the relationship between treatment fee and actual treatment costs, since conventional physical-chemical and biochemical parameters are not necessarily linked to wastewater treatability. New advanced respirometric methodologies could be used as wastewater characterization techniques, since they are particularly suited to represent the effect of a given wastewater on the final wastewater treatment plant. Hence, they could be better correlated to treatment costs. The instrument developed is composed of two parallel moving bed continuous flow completely mixed reactors of the working volume of about 5 l each, equipped with oxygen sensors connected to a computer that acts as a controller and as a data acquisition and processing unit. Some examples of experimental results obtained with synthetic waste and with real sewage are presented.
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Dzhumagulova, Nazira, Ivan Gavrilov und Dinh Dap Nguyen. „Activated sludge biocenosis regulation for intensifying aerating constructions“. MATEC Web of Conferences 193 (2018): 02015. http://dx.doi.org/10.1051/matecconf/201819302015.
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One of the most effective methods of wastewater treatment is a biochemical method that almost completely disposes various dissolved organic matter. To improve the oxidation capacity of aerotanks and to control the biochemical processes of wastewater treatment, it was necessary to determine experimentally biocenosis variability influenced by the environment and other factors.The goal of the present research is intensification of biological wastewater treatment by means of direct effect upon the metabolism of activated sludge microorganisms. The experiment studied the organization of species and quantitative composition of active sludge biocenosis in aerotanks while removing contaminants from wastewater. The experiments were carried out in continuous-flow aerotanks of publicly owned treatment facilities. Everyday over a period of three weeks, samples of microorganisms were obtained from aerotanks, quality and quantity objectives of purified water.
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Welz, P. J., G. Holtman, R. Haldenwang und M. le Roes-Hill. „Characterisation of winery wastewater from continuous flow settling basins and waste stabilisation ponds over the course of 1 year: implications for biological wastewater treatment and land application“. Water Science and Technology 74, Nr. 9 (18.06.2016): 2036–50. http://dx.doi.org/10.2166/wst.2016.226.
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Wineries generate 0.2 to 4 L of wastewater per litre of wine produced. Many cellars make use of irrigation as a means of disposal, either directly or after storage. In order to consider the potential downstream impacts of storage/no storage, this study critically compared the seasonal organic and inorganic composition of fresh winery effluent with effluent that had been stored in waste stabilisation ponds. Ethanol and short chain volatile fatty acids were the main contributors to chemical oxygen demand (COD), with average concentrations of 2,086 and 882 mgCOD/L, respectively. Total phenolics were typically present in concentrations <100 mg/L. The concentration of sodium from cleaning agents was higher in the non-crush season, while the converse was true for organics. The effluent was nitrogen-deficient for biological treatment, with COD:N ratios of 0.09 to 1.2. There was an accumulation of propionic and butyric acid during storage. The composition of the pond effluent was more stable in character, and it is possible that bacterial and algal nitrogen fixation in such systems may enhance biological wastewater treatment by natural nitrogen supplementation. It is therefore recommended that if land requirements can be met, winery effluent should be stored in ponds prior to treatment.
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Röske, I., K. Röske und D. Uhlmann. „Gradients in the taxonomic composition of different microbial systems: comparison between biofilms for advanced waste treatment and lake sediments“. Water Science and Technology 37, Nr. 4-5 (01.02.1998): 159–66. http://dx.doi.org/10.2166/wst.1998.0608.
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The application of in situ hybridization with group specific oligonucleotide probes detected by epifluorescence microscopy and confocal laser scanning microscopy was tested to identify spatial gradients in the distribution of bacteria in biofilms of plug flow reactors and in the bottom sediment layer of a drinking water reservoir. The two tubular biofilm reactors were fed with the effluent from a full scale biological wastewater treatment plant to which were added the chlorophenols whole degradation was being investigated. One was operated as a continuous-flow reactor and the other as a sequencing batch reactor. The vertical gradients in the microbial colonization of the sediment were analyzed by means of glass slides exposed to the sediment. In the biofilms of both reactors the beta-Proteobacteria dominated. The Cytophaga-Flavobacterium group and the Gram-positive bacteria were also abundant. Only small amounts of gamma-bacteria could be detected. This is contrary to findings using traditional cultivation methods. Unlike the biofilms in the reactor, the bacterial Aufwuchs on the glass slides in the sediment presented a surprising diversity of morphological types and size classes of bacteria.
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Hansen, Kamilla M. S., und Henrik R. Andersen. „Energy Effectiveness of Direct UV and UV/H2O2Treatment of Estrogenic Chemicals in Biologically Treated Sewage“. International Journal of Photoenergy 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/270320.
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Continuous exposure of aquatic life to estrogenic chemicals via wastewater treatment plant effluents has in recent years received considerable attention due to the high sensitivity of oviparous animals to disturbances of estrogen-controlled physiology. The removal efficiency by direct UV and the UV/H2O2treatment was investigated in biologically treated sewage for most of the estrogenic compounds reported in wastewater. The investigated compounds included parabens, industrial phenols, sunscreen chemicals, and steroid estrogens. Treatment experiments were performed in a flow through setup. The effect of different concentrations of H2O2and different UV doses was investigated for all compounds in an effluent from a biological wastewater treatment plant. Removal effectiveness increased with H2O2concentration until 60 mg/L. The treatment effectiveness was reported as the electrical energy consumed per unit volume of water treated required for 90% removal of the investigated compound. It was found that the removal of all the compounds was dependent on the UV dose for both treatment methods. The required energy for 90% removal of the compounds was between 28 kWh/m3(butylparaben) and 1.2 kWh/m3(estrone) for the UV treatment. In comparison, the UV/H2O2treatment required between 8.7 kWh/m3for bisphenol A and benzophenone-7 and 1.8 kWh/m3for ethinylestradiol.
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Ribeiro, Renato P., Rodrigo F. Bueno, Roque P. Piveli, Débora C. Kligerman, William Z. de Mello und Jaime L. M. Oliveira. „The response of nitrous oxide emissions to different operating conditions in activated sludge wastewater treatment plants in Southeastern Brazil“. Water Science and Technology 76, Nr. 9 (06.07.2017): 2337–49. http://dx.doi.org/10.2166/wst.2017.399.
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Abstract The continuous measurements of N2O emissions from the aeration tanks of three activated sludge wastewater treatment plants (WWTPs) operated with biological nitrogen removal (BNR) and non-BNR were performed during the different operating conditions of several parameters, such as aeration, dissolved oxygen (DO) profiling and organic shock loading (with landfill leachate). The nitrification process is the main driving force behind N2O emission peaks. There are indications that the variation of the air flow rate influenced N2O emissions; high N2O emissions denote over-aeration conditions or incomplete nitrification, with accumulation of NO2− concentrations. Thus, continuous measurements of N2O emissions can provide information on aeration adequacy and the efficiency of complete nitrification, with major focus on DO control, in order to reduce N2O emissions. An additional concern is the observed propensity of WWTPs in developing countries to receive landfill leachates in their wastewater systems. This practice could have adverse effects on climate change, since wastewater treatment during periods of organic shock loading emitted significantly higher amounts of N2O than without organic shock loading. In short, non-BNR WWTPs are subject to high N2O emissions, in contrast to BNR WWTP with controlled nitrification and denitrification processes.