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Showing 7 results for Wastewater Treatment


Volume 1, Issue 1 (3-2023)
Abstract

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.
 

Volume 6, Issue 3 (12-2022)
Abstract

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.                                                                
              
Mohammad Goodarzi, Hossain-Ali Rafiee-Pour, Fereshteh Jookar Kashi,
Volume 11, Issue 1 (3-2020)
Abstract

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.

Volume 12, Issue 4 (12-2024)
Abstract

Aims: In this study, we evaluated the performance of direct microbial fuel cells using citric acid wastewater as a substrate under different concentrations of MLSS 1000 mg.L-1 and 3000 mg.L-1. 
Materials & Methods: Aspergillus niger yeast was used as a microorganism over 4 days and nights of this experiment. A Nafion membrane was used for proton transfer, and graphite plates were used for electron transfer. COD removal efficiency, maximum open circuit voltage, power, and current density were evaluated. 
Findings: The general trend of energy production and removal efficiency showed that energy production increased with increasing MLSS. The maximum of these variables was recorded for MLSS of 3000 mg.L-1, achieving a removal efficiency of 93%, an open circuit voltage of 500 mV, and power and current density of 24345 µW.m-2 and 444 mA.m-2, respectively. 
Conclusion: Our results showed that the designed MFC suits wastewater treatment and energy recovery.


Volume 17, Issue 2 (7-2017)
Abstract

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.

Volume 17, Issue 2 (7-2017)
Abstract

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.

Volume 23, Issue 5 (11-2023)
Abstract

Industrial progress has ushered in the production of a diverse array of pollutants, encompassing both organic and non-biodegradable substances, such as hydrocarbon compounds derived from petroleum. As the discernible environmental ramifications of these pollutants continue to escalate, the quest for efficacious methodologies for wastewater remediation assumes paramount importance. Among the emergent technologies, plasma technology has garnered considerable acclaim due to its capacity to obliterate a myriad of pollutants. Plasma, which ensues from the application of high voltage to either a gaseous or liquid medium, engenders profoundly reactive species capable of dismantling intricate organic compounds. Similarly, ozone, an exceedingly potent oxidizing agent, has long commanded recognition for its aptitude in the degradation of pollutants. Its robust oxidative attributes render it an invaluable instrument in the realm of wastewater treatment. Ozone treatment entails the infusion of ozone gas into the contaminated aqueous medium, whereupon it engages pollutants in a transformative reaction, rendering them into less deleterious byproducts. By amalgamating the ozonation process with plasma technology, we can harness the merits of both modalities and achieve synergistic effects. This hybridized approach proffers several advantages vis-à-vis individual treatment methodologies, including augmented pollutant removal efficiency, diminished treatment duration, and amplified energy efficiency. The plasma-ozonation process exploits plasma's propensity for the generation of reactive species, capable of reacting with the organic constituents in wastewater. The ensuing ozonation phase augments the degradation of these constituents, engendering a more efficacious and comprehensive removal process. Prior investigations have scrutinized the efficacy of ozone and plasma in isolation for the eradication of p-nitrophenol, a ubiquitous organic pollutant encountered in industrial wastewater. These inquiries have methodically examined various parameters to ascertain their influence on pollutant removal efficiency. Factors such as applied voltage, ozone dosage, initial pH, reaction duration, and initial solution concentration have been subjected to meticulous scrutiny to optimize the treatment regimen. In the present study, we have devised an innovative mathematical model to probe the interplay between these two independent variables: plasma technology and ozonation. The model incorporates a quadratic equation and employs analysis of variance (ANOVA) to gauge the significance of each variable and discern the optimal conditions for pollutant removal. Through scrutiny of the model, we have ascertained that the pinnacle of removal efficiency, surpassing 95%, materializes under specific parameters. These parameters encompass an applied voltage of 14 kV, an oxygen flow rate of 6 L/min, an initial pH of 10, a reaction duration of 6 minutes, and an initial concentration of 200 mg/L. These revelations offer valuable insights into the operational parameters that yield superlative results for pollutant removal within the context of the plasma-ozonation process. The efficacious integration of ozone and plasma technologies in wastewater treatment proffers a promising panacea for the elimination of p-nitrophenol pollutants and sundry other organic constituents. By fine-tuning the process parameters in alignment with the model's recommendations, we can attain exceptional levels of pollutant elimination whilst concurrently minimizing energy consumption and treatment duration. This research significantly contributes to the perennial endeavors aimed at fashioning sustainable and efficient remedies for industrial wastewater treatment, endowing valuable perspectives for their future deployment and widescale application in industrial settings.




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