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A bench scale aerobic sequencing batch reactor (SBR) was evaluated in terms of its potential to treat synthetic dairy wastewater. The 2-l plexiglass bioreactor was supplied with oxygen via a fine bubble air diffuser, fed with synthetic dairy wastewater under various operational conditions. To analyze the process, three significant independent variables — influent chemical oxygen demand (COD), mixed liquor volatile suspended solids (MLVSS), and aeration time — were assessed. Three dependent process and quality parameters (as process responses) were also evaluated: total COD removal efficiency, sludge volume index (SVI) and final pH. The experiments were based on a central composite design (CCD) and analyzed using response surface methodology (RSM). The treatment was limited to the following concentration regimes: COD (1000, 3000 and 5000 mg/l), MLVSS (3000, 5000 and 7000 mg/l) and aeration time (2, 10 and 18 h). Maximum COD removal efficiency (of 96.5%) was obtained for an influent with the following characteristics: CODin: 3000 mg/l, MLVSS 5000 mg/l, and aeration time of 18 h. The study demonstrated the capability of aerobic SBRs for high COD removal from dairy industrial wastewater. Easy operation, low cost, and minimal sludge bulking condition were some of advantages of the SBR system as an option for biological treatment of medium-strength industrial wastewater. The present study provides valuable information about relationships between quality and process parameters for different values of operating variables.

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Treatment of organic leachate is one the most controversial topics around the world which led this study to assess the efficiency of the combined oxidation and adsorption treatment (COAT) process in the treatment of leachate by considering local experiments. The removal of effluent parameters (TDS, COD, BOD) was enhanced by oxidizing the GAC surface as a catalyst with NaOH before the process and by ozone within the procedure as well. Assessing the interacting effect of operating variables (i.e., ozone concentration, GAC density, reaction time and pH) provides valuable information for optimization. Response Surface Methodology (RSM) was employed. The optimized model’s circumstances are the reaction time of 30.77 min, ozone dosage of 141.29 mg/l, pH of 7.2, and the GAC density of 1.29 gr/cm³ with the predicted removal percentage of 51.63%,62.84% and 56.13% for TDS, COD and, BOD respectively.
 

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Wastewater planning management is a complex problem involving agricultural, rural and industrial interests. In countries facing rapid population growth, identifying methods that can allow them to take good decisions among several competitive alternatives is of utmost importance. The purpose of this paper is to present a methodology for a wastewater planning management system using a Multi-criterion Decision-making (MCDM) method based on utility function. It allows one to take into account a multiple conflicting multi criterion context in terms of objective specification, criteria, criterion scales and construction of a payoff matrix that consists of the alternative versus criteria array. These objectives deal with groundwater protection, effluent quality, wastewater reuse, system reliability and resources needed. A number of wastewater treatment techniques are presented as alternative action plans from which the most satisfying alternative is to be chosen. In order to select on appropriate management scheme, we propose to use the UTA (Utility Additive) method. This method is interactive and permits the decision maker (DM) to select the best solution according to his viewpoint . The UTA method proceeds in two steps: the assessment of optimal utility using piecewise linear programming techniques and sensitive analysis using a post - optimal procedure. An application of UTA method in wastewater planning management system is presented for the first time and some extensions of the method are discussed.

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The aim of this study, in the first step, was to recover the protein content in wastewater of fish meal factories using chitosan, chitosan nanoparticles and chitosan-aluminum sulphate composition. In the second step, the extracted protein was assessed for its  essential amino acids profile.  Also, the  reduced amount of proteins in the waste water was evaluated by measuring different parameters such as turbidity, pH, COD. Finally, chitosan nanoparticles characteristics were investigated using atomic force microscopy. Results showed that turbidity, COD and soluble protein significantly decreased upon  adding different concentrations of chitosan, nanoparticle of chitosan and chitosan-alum (p<0.05). The maximum protein recovery was related to chitosan-alum composition and chitosan nanoparticles with no significant difference between these two treatments. Evaluation of recovered protein in term of amino acids profiles showed that there were essential amino acids such as histidine, lysine, methionine and phenylalanine in protein of fish meal wastewater.      

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Phosphate ions is one of the chemical pollutants that enters to the surface and underground water through municipal, industrial and agricultural wastewater. The aim of this study is to investigate the removal of phosphate from wastewater by Chlorella vulgaris and Spirulina platensis. To this purpose the microalgae added to 350 ml wastewater in lab experiment. In order to evaluate the effect of phosphorus removal, the experiment were performed during 8 days. The initial dry weight of Chlorella vulgaris and Spirulina platensis in wastewater samples were 0.02 and 0.05 g/L, respectively. During the growth period, the concentration of phosphate in aqueous solution were measured on days 1st, 4th, 6th and 8th by APHA standard methods through Bio spec-1601 spectrophotometer. Based on the results, the percentage of phosphorus removal by Chlorella vulgaris was 40.65, 38.0124.45 and 72.21 , and by Spirulina platensis was 20.13, 20.01, 10.44 and 42.79 for days 1 to 4, 4 to 6, 6 to 8 and 1 to 8, respectively. The final dry weight of Chlorella vulgaris and Spirulina platensis in wastewater samples were 3.93 and 1.93 g/L, respectively. From this study it can be concluded that the algae are able to remove phosphorus from wastewater and Chlorella vulgaris has higher ability of reducing phosphorus from waste water, and could be good candidate to reduce the phosphate in wastewater treatment.

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Research subject: Osmosis membrane bioreactor is one of the best industrial wastewater treatment methods. The main advantage of using osmosis process is its operation at low hydraulic pressures which has a better performance in removing pollutants and low energy consumption than other methods                        
Research approach: In this research, Nano porous Titanium dioxide powder with a specific surface area and anatase wall was synthesized through a thermal process using cetyltrimethylammonium bromide (CTAB) as a surfactant directing agent and a pore-creating agent.Ultrafiltration nanocomposite membranes were made using modified titanium dioxide (TiO₂) (MT) and polysulfone (PSf) by phase the inversion method. The morphology and structure of the prepared membranes and nanoparticles were investigated using by atomic fourier transforms infrared spectroscopy(FESEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this research, bovine serum albumin (BSA) was used as simulated wastewater for the feed solution. The fabricated ultrafiltration membranes were tested in osmosis membrane bioreactor (OMBR) system due to lower energy and fouling. 0.6 % solution of poly (sodium 4-styrene sulfonate) was used as an osmotic solution. Comparative separation performance and antifouling properties of both nanocomposites in several analyzes such as water contact angle measurement, pure water flux and filtration of different concentrations of bovine serum albumin solution. BSA and fouling resistance have been investigated


Main results:  TThe results that Due to the addition of MT nanoparticles to the polymer matrix, the hydrophilicity and surface energy of the membrane increased, which led to the improvement of the membrane performance. The membrane containing 1% titanium oxide nanoparticles showed the best result. For example, for feeding with a concentration of 200 ppm, the water flux increased from 20 to 38.5 L/ m² h, and the percentage of returning lethal solution decreased from 19.6 to 30 g/ m² h. The flux recovery in this membrane was 96%, which indicates the antifouling property of the modified nanocomposite membrane.                                                                
              

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Backgrounds: Hospital sewage is known as an important source of human pathogenic bacteria such as methicillin resistant Staphylococcus aureus (MRSA) strains disseminated from hospital to the environment. This study aimed to investigate the presence of MRSA in the treated outgoing wastewater collected from a referral hospital in Tehran, Iran.
Materials & Methods: During 2015, sampling was carried out at two stages from a hospital wastewater. All black colonies with halos on HiCrome aureus agar medium supplemented with oxacillin were collected and identified as MRSA using specific primers for nucA and mecA genes. Isolates susceptibility to 18 antibiotics was determined according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI). Bacterial typing was performed for the isolates using a combination of Phene plate (PhP) typing, prophage typing, staphylococcal cassette chromosome mec (SCCmec) and ccr typing methods.
Findings: A total of 79 MRSA isolates were confirmed using specific primers and showed susceptibility to quinupristin-dalfopristin, vancomycin, chloramphenicol, and linezolid. High resistance to penicillin, ciprofloxacin, kanamycin, tobramycin, and erythromycin was reported. Sixteen PhP types consisting of eight common types (CTs) and eight single types (STs) were identified among the strains, among which CT1 was the dominant type. Also, two prophage patterns and four prophage types were identified, and all the strains were positive for SCCmec type III and ccr type 3.
Conclusion: The results of this study revealed that sewage-treatment process was able to remove community-acquired MRSA (CA-MRSA) strains; however, hospital-acquired MRSA (HA-MRSA) strains were able to survive during the treatment process in this hospital.

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Aims: The dyes are high usage chemical compounds in textile industry. Discharge of colored effluent to the water sources, effect on the unpleasant appearance and the solubility of gases. The dyes reduce light penetration to the lower layers of water and photosynthetic activity. They caused cancers and variety of mutations. In this research, the decolorization ability of Reactive Red 152 dye by isolated strains from textile wastewater was measured, also environmental conditions were optimized.
Materials and Methods: In this experimental study, the bacterial strains were isolated from samples collected from different parts of textile wastewater. The dye decolorizing bacteria were screened. The decolorization ability of the strains was evaluated under different conditions such as incubation time from 0 to 72 hours, pH 6 to 9, different dye concentrations from 50 to 400mg/l and different carbon sources.
Findings: Ten strains were isolated from Kashan textile wastewater that 4 strains showed high ability in decolorization. The highest decolorization was observed after 48 hours, pH=9, 50mg/l concentration of dye and glucose as carbon source.
Conclusion: Textile wastewater contains bacterial strains which have high decolorization ability. Therefore, we can use these bacteria for decolorization of wastewater dyes.

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The waste produced by households, industry and factories to use as wash water and cooling systems and equipment, is caused environmental complications. Waste created a suitable environment for the growth of odor and pathogenic bacteria. This study aimed to isolate microorganisms in the wastewater and use them for the reduction of BOD (biochemical oxygen demand) and COD (chemical oxygen demand).The samples were collected aseptically from different parts of wastewater of herbal distillation industry. The bacterial strains were isolated from the samples in LB media. The isolates were distinguished based on the morphology and biochemical characteristics. Among the total 69 isolates, four isolates were selected to measure the ability to reduce BOD and COD and added to the waste water. Reduction of BOD was measured using BOD meter. Also, COD was determined by titration method. The isolates were identified by biochemical tests. The amount of BOD and COD reduction after adding selected strains to wastewater was 47.43 - 71.82% and 44.79 - 56.5% respectively. Also, the consortium of bacterial strains showed better ability to reduce BOD and COD (38.32-57.29%and 76.6-83.21% respectively). The results determined that wastewater contains bacterial strains which have shown significant reduction in BOD and COD and organic matter decomposition in wastewater and reuse it in agricultural and industrial sectors. Therefore, we can use these bacteria for wastewater treatment.

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Over the past few years, due to the shortage of forest resources as well as the increasing consumption of paper and paperboard, many pulp and paper manufacturers have developed the use of different sources of recycled (secondary) fibers. Therefore, recycling of paper is an effective and eco-friendly way to preserve forest resources, which eventually save the natural diversity and energy. The use of biotechnology in various sectors of the cellulosic products industries such as bio-pulping, bio-bleaching, bio-deinking, bio-wastewater treatment, etc. has been considered and good achievements have been obtained in this field. One of the most important applications of biotechnology in the cellulosic industries is the use of enzymes in the processing of recycled fibers. The use of enzymatic technologies, as environmental friendly process, has led to changes in industrial processes as much as possible and indicated great potential in solving many problems of recycled fibers, especially problems related to waste paper deinking, pulp drainage rate, fiber hornification, refining and stickies materials. In general, deinking with enzymes under acidic or neutral conditions declines the chemicals usage and reduces the yellowing of recycled paper under conventional alkaline deinking conditions. Today, the use of cellulosic enzymes (cellulase and hemicellulase) and oxidative enzymes (such as laccase) as well as amylase and pectinase have shown acceptable results for deinking different types of waste paper and most experiments in semi-industrial as well as industrial units have shown that deinking with them can reduce the cost of chemicals, increase the separation of ink particles

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Oil and gas processing activities is causes excess water consumption, which leads to excessive production of wastewater. This produced waste water contains mineral and biological compounds which can contaminate water and ground water. Vast amount of this industries’ produced wastewater in Oil-rich countries which mostly are arid countries, lead them to find more effective methods for water reuse as a new water resources. One of the most important water pollutant are heavy metals, so investigator are believe that heavy metals toxicity into environment is more than which disperse from radioactive toxicity to ground water and seas. Various physical, chemical and biological methods of waste water treatment are applied in refining and petrochemical industries. considerable amount af mercury with different operational units’ wastewater is discharge to environment from refinery units. Since mercury is not biodegradable and tend to accumulate in living organisms, we must be able to control it by using effective methods. Application of membrane filtration is new method for water and wastewater treatment industry. In this research, by application of case study on one of the nation’s gas refineries, reverse osmosis membrane system performance under different operating conditions, was studied. For this purpose effects of variable parameters, namely operating pressure (5, 7, 9 and 11 bar), pH (3, 6, 9, 11) and mercury concentration (1, 2, 4, 8 and 12 mg/l) on removal performance were studied. Considering removal performance of mercury, COD, TDS, EC, Turbidity and also membrane flow rate, optimum operating condition was obtained. Base on the results, reverse osmosis membrane performance is efficient in optimum parameters’ value, namely 7 bar pressure and pH=9 from permeate water quality and economical aspects. by increasing system pressure a significant decline in mercury and COD removal efficiency was observed. removal efficiency of mercury, COD, and TDS in 7 bar pressure condition was 91.35%, 99.55%, and 94.89% respectively and also permeat flowrate was acceptable, so 7 bar was found as optimum pressure. On the next stage af investigation, although by increasing wastewater sampel’s pH, a considerable increase in mercury and COD removal efficiency was observed, it cause a dramatic rise in TDS and turbidity in feed wastewater and also in permeate stream. More over high value of pH, namely pH=11 can make system prone to fouling. So pH=9 was choosen as a optimum pH. Finally reverse osmosis membrane performance in encountering with possible shocks and high concentration of influent mercury was investigated. Although results shows a significant decrease in membrane removal efficiency in encountering with high influent mercury concentration, reverse osmosis membrane system efficiency in mercury removal is acceptable in encountering conventional mercury concentration of refineries. reverse osmosis membrane performance is efficient in optimum parameters’ value namely 7 bar pressure and pH=9, so removal efficiency of mercury,COD, and TDS was 97.5%, 99.755 and 93.29% respectively.

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The composition of wastwwater in sewer lines are changing due to their nature. Wastewater contains large amount of organic materials, therfore it is suseptible to biological disintegritaion. Normally the conditions of sewers dicctate and promote the type of growth of bacteria being either aerobic or anaerobic. Previous studies have shown that large number of concrete sewer lines were found to beeffected by anaerobic bacteria activites. In this experimental investigation the aerobic biological transformation of organic matter in small diameter gravity slope wastewater collection system is evaluated. In this study a sewer network reactor at pilot scale was designed and built. The reactor consists of 15 meters length of PVC with 0.1 m diameter, two storage tanks and re circulating pump. The whole system was set up on a platform with adjustable slope. To ease the Formation of attached growth of micro organism a plastic net was attached on the inner surface of PVC pipe, thus a rough surface for attachment of microorganisms was formed. Due to the variation of hydraulic mean diameter, contact area with flowing wastewater was ranged from 1.88 to 3.77 m2 (half or full). Synthetic wastewater with characteristic municipal wastewater was used. A settled activated sludge fromYasreb wastewater treatment plant in Qaemshahr city was used to start and accelerate the biofilm growth in the reactor. In order to study bio-film attachment rate two P.V.C square plates in dimensions of 10*10 cm were placed perpendicular on the direction flow of wastewater. The reactor was conducted under aerobic conditions in a hydraulic retention time of 7 hours under constant temperature changed about 20 ±3 C. In this study parameter such as BOD, COD, TN and NH3-N and NO3-N were measured on daily basis. The thickness of biofilm increased and formed as irregular with thickness of 3-4.7 mm. Biofilm characteristics analysis showed that density and surface density were respectively 55 mg Ts/cm-3 and between 22.3 and 33.1 m-2. The concentration of suspended biomass was varied from10-15 mgl-1 at optimum COD removal. Oxygen consumption rate was estimated from decreasing rate of soluble oxygen concentration which reached to 0.21 mg l-1 min-1 after 3 weeks of operation. The highest reduction in COD and biological oxygen demand (BOD) concentration were 59% and 54% respectively . By increasing the chemichal oxygen demand (COD) loading by 70 %, removal rate of COD reduced by only 9%. Due to high COD concentration of wastewater effuluent, the nitrification process was limited. In order to nitrify the waste water, a longer hydraulic retention time(HRT) or higher recirculation is required. From the results and analysis it can seen be seen that proposed innovative method is applicable in many fields such as mountainous area, area with water stress ratio, water scarce area and ... which normally an application of conventional wastewater treatment either are costly or impractical. And also with regard to publicized incentives for using waste water reclaimation as a source of water for agricultral irrigation, thus with more precision in desigin and operation, an effluent of these new configuration of PVC pipes can be used in agri-industry

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Composting is certainly one of the most natural types of recycling process. One of the problems during this process is the management of leachate that adversely affects human and ecological health in the area. Leachate is a complex organic compound which is difficult to be degraded biologically by conventional methods. Advanced oxidation processes (AOPs) have been widely studied for the degradation of diverse types of industrial wastewaters. The purpose of the study was aimed to evaluate the efficiency of hydrogen peroxide with ultraviolet light (H2O2/UV) for the treatment of high chemical oxygen demand (COD) strength compost leachate, color and turbidity using response surface methodology (RSM) under central composite design (CCD). The various operation conditions such as initial pH, dose of hydrogen peroxide, and UV-contact time was examined in order to optimize the maximum COD and color removal and turbidity of the compost leachate. The total number of 20 experimental runs was set. Optimal condition obtained for H2O2/UV process were initial pH 7.5, dose of hydrogen proxide 2.3 mL/L, and UV-contact time 95 min. In these conditions, the removal of COD and color and turbidity for H2O2/UV process was 12.32%, 20.83%, and 8.68 NTU, respectively. The results indicated that the H2O2/UV process has been successful in reducing turbidity but in COD removal efficiency is not well. Composting is certainly one of the most natural types of recycling process. One of the problems during this process is the management of leachate that adversely affects human and ecological health in the area. Leachate is a complex organic compound which is difficult to be degraded biologically by conventional methods. Advanced oxidation processes (AOPs) have been widely studied for the degradation of diverse types of industrial wastewaters. The purpose of the study was aimed to evaluate the efficiency of hydrogen peroxide with ultraviolet light (H2O2/UV) for the treatment of high chemical oxygen demand (COD) strength compost leachate, color and turbidity using response surface methodology (RSM) under central composite design (CCD). The various operation conditions such as initial pH, dose of hydrogen peroxide, and UV-contact time was examined in order to optimize the maximum COD and color removal and turbidity of the compost leachate. The total number of 20 experimental runs was set. Optimal condition obtained for H2O2/UV process were initial pH 7.5, dose of hydrogen proxide 2.3 mL/L, and UV-contact time 95 min. In these conditions, the removal of COD and color and turbidity for H2O2/UV process was 12.32%, 20.83%, and 8.68 NTU, respectively. The results indicated that the H2O2/UV process has been successful in reducing turbidity but in COD removal efficiency is not well. The results indicated that the H2O2/UV process has been successful in reducing turbidity but in COD removal efficiency is not well.

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Introduction: Petrochemical industry is one of the major industries playing significant role in the economy of Iran. In general, petrochemical effluents contain various contaminants including suspended solids, organic matters, oil and grease, metal salts, sulfide, ammonia, hydrocarbons, cyanides, volatile organic compounds (VOCs) and other toxic substances. In most of petrochemical complexes, wastewaters are treated by activated sludge process along with the oil/water separation systems as a pretreatment. Since the performance evaluation of wastewater treatment plant is required to assess the effluent quality, to meet higher treatment requirement and to know the feasibility of handling higher hydraulic and/or organic loadings, this study was conducted to evaluate the performance of a full-scale petrochemical wastewater treatment plant.
Materials and methods: Wastewater treatment system consists of a screening unit, an API, an equalization basin, coagulation and flocculation, DAF system, aeration tanks, primary and secondary clarifier and filtration. The treatment plant was designed to treat the wastewater generated from different units of petrochemical complex with reuse purposes of treated effluent. To evaluate the performance of the treatment plant, 12-h composite flow weighted samples were carried out in 4 days within 6 month and were analyzed for COD, BOD5, TDS, TSS, phenol, cyanide, oil, ammonia and TKN in accordance to standard methods. Microbial structure of activated sludge was also evaluated. Overall performance of the plant and the performance efficiency of each unit were calculated.
Results: According to the results, the actual average influent flow was significantly lower than the average design flow based on the long-term data and our measurements. This increases the hydraulic retention time (HRT) in all units in the WWTP. Based on the results, the values of COD, BOD5 and TSS in the influent and effluent were 1319±230, 967±491 and 227±174 mg/l and 73.6±19.6, 33.6±25.9 and 6.4±5.9 mg/l respectively. The ratio of BOD5/COD was calculated about 0.58 indicates a good potential for biodegradability of the wastewater. The results also revealed that 68.5% removal of COD and 81.9% removal of BOD5 have been occurred in preliminary and primary units while; these units are usually designed for the elimination of oil and suspended solids as well as the equalization of quantitative and qualitative parameters of the influent. At an organic loading of 0.48±0.15 kg/m3.d the removal efficiencies for COD and BOD5 in biological unit were calculated about 37 and 46% respectively. The mean value of MLSS within the biological reactor was 1463 mg/l. In addition, the mean plus standard deviation values of MLSS measured in returned activated sludge (RAS) were 2323 ± 1080 mg/l. According to the daily average concentrations of COD in the effluent of the WWTP, in some cases within the study period, the COD values were exceeded from national discharge standards. Microbial analysis showed that among the isolated bacterial strains, the genus belonging to Alcaligenes, Pseudomonas, Bacillus and Moraxella as heterotrophic nitrifying bacteria was identified as predominant strains in biological unit.
Conclusion: Based on the results, in 64% of our measurements (135 days from 209 days of study period), the daily average effluent COD values were above national guidelines for surface water discharge (60 mg/l). In 3% of the time during the study period, the daily average values of COD in the effluent were more than 200 mg/l. The results also indicated that the average effluent concentration of oil was significantly higher than the expected design value.

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Leachate generated in the landfill due to the complex structure and high pollution requires developed physical and chemical and biological treatment methods. Aerobic granular sludge is one of the newest technology of immobilized microbes that has the potential to improve the biological wastewater treatment technology. One of the leachate treatment method which have been highly regarded recently is the leachate treatment by aerobic granules in the SBAR reactor. This study has been done for the purpose of treatment of leachate with aerobic granular. In order to optimize the formation of the granules and use it in the leachate treatment of this experiment, the construction of granules and leachate treatment has been done in two distinct phases: granules production has been done in the SBAR reactor for 28 days with increase loading to 6000 mg per liter and leachate treatment has been done in the same reactor in 24 days to loading 6000 mg per liter. The reactor used in this test is made of Plexiglas and has the dimensions 75 *20*20 cm3 and the volume of 28 liter. To link the upper and lower part of the reactor as well as effective mixing in the reactor an airlift PVC pipe has been used with the height of 50 and diameter of 20 cm. Some holes with the diameter of 2 cm has been created at the bottom of the airlift pipe and aeration is in the middle of airlift pipe and the bottom of reactor to led to rotation confusion and the oxygen transfer well done. For granules cultivation the synthetic wastewater containing glucose has been used as the carbon source, the ammonium chloride as the nitrogen source, the potassium dihydrogen phosphate as the phosphorus source as well as the micronutrients such as magnesium sulfate, ferrous sulfate, calcium chloride, potassium dihydrogen phosphate. At first the granules are made with synthetic wastewater in 6-hour cycles containing 30 minutes feeding, 270 minutes’ aeration, 30 minutes settling, 30 minutes’ wastewater discharge. In this experiment, the temperature has been controlled in the range of 20-23 C and DO in the range of 6-8 ppm and PH in the range of 7.5-8.3. In the next stage, the feasibility of using these granules in the leachate treatment has been tested. The results of the MLSS, SVI, VELOCITY, DIAMETER, COD REMOVAL tests show that the granules produced from synthetic glucose wastewater will be able to purify leachate. Synthetic sewages loading in the 6-hour cycles and the organic loading increases have been done till the formation of granules in 28 days. After each cycle, the parameters mentioned above were examined and the sludge morphology. With the entering of synthetic sewage to the reactor, at first the suspended solids increased and the granules' seeds production reduced. With the consolidation of granules and its sustainability, the leachate is injected to the reactor and is replaced by the artificial sewage. With the arrival of leachate to the reactor, the granules start to disintegrate and thus lead to an increase in the suspended solids of the system. Due to the change of the raw sewage and replacement of leachate instead of synthetic sewage, in some granules collapse happened. The results show that when granules are accustomed to the leachate entering the reactor, increase of bacterial activity lead to the improvement of efficiency of leachate treatment in the system and the efficiency of COD removal reached 90%.

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Nowadays, heavy metals are one of the greatest environmental problems. This problem intensifies by development of great industries and increasing of pollutant and contaminant resources daily. Increasing of population and reduction of water resources detect importance of waste treatment and reuse of water resources. Studies on treatment of effluents containing heavy metals have showed that adsorption to be a highly effective technique for removing heavy metals from aqueous solutions. The aim of this research was to use of absorbent materials (kaolin clay) to remove chromium (VI) from the wastewater in discontinuous system According to the results, optimum conditions of chromium removal were, pH=5, primary concentration of pollutant: 1000(mg/l), fine grained weight of consumed kaolin in constructing concrete: 30%, equilibrium time: 360 minutes, absorbing capacity: 3.06 mg/g absorbent. Covering the concrete surface with kaolin absorbent can be an innovative and useful solution for increasing the rate of elimination of pollutant and contaminants, cost reduction and accelerating the absorption process. Absorbing capacity of chromium is 29.5 mg/g absorbent in this condition respectively. Real waste sample are used for confirming the application of concrete in ordinary conditions of wastewater basin in accordance of optimum conditions of kinetics wastewater. Elimination rates of heavy metal of chromium were 90.3% in optimum condition with real samples that has been got from industrial factory. Therefore, it could be concluded that modified concert presents a good potential for treatment of Cr in wastewater. However, further research should be applied for continuous removal of heavy metal in large-scale. According to the result , mixing Kaolin in the concrete could be used to increase the Durability and adsorption efficiency of Chromium .