Showing 5 results for Wastewater
Majid Hosseinzadeh, Gholamreza Nabi Bidhendi, Ali Torabian, Naser Mehrdadi,
Volume 8, Issue 24 (4-2014)
Abstract
Background: Considering the toxic effects of heavy metals and microbial pathogens in industrial wastewaters, it is necessary to treat metal and microbial contaminated wastewater prior to disposal in the environment. The purpose of this study is to assess the removal of heavy metals pollution and microbial contamination from a mixture of municipal and industrial wastewater using membrane bioreactor.
Methods:A pilot study with a continuous stream was conducted using a 32-L-activated sludge with a flat sheet membrane. Actual wastewater from industrial wastewater treatment plant was used in this study. Membrane bioreactor was operated with a constant flow rate of 4 L/hr and chemical oxygen demand, suspended solids concentration, six heavy metals concentration, and total coliform amounts were recorded during the operation.
Results: High COD, suspended solids, heavy metals, and microbial contamination removal was measured during the experiment. The average removal percentages obtained by the MBR system were 81% for Al, 53% for Fe, 94% for Pb, 91% for Cu, 59% for Ni, and 49% for Cr which indicated the presence of Cu, Ni, and Cr in both soluble and particle forms in mixed liquor while Al, Fe, and Pb were mainly in particulate form. Also, coliforms in the majority of the samples were <140 MPN/100mL that showed that more than 99.9% of total coliform was removed in MBR effluent.
Conclusion: The Membrane Biological Reactor (MBR) showed a good performance to remove heavy metals and microbial matters as well as COD and suspended solids. The effluent quality was suitable for reusing purposes.
Nadiya Shahandeh , Reza Jalilzadeh Yengejeh,
Volume 12, Issue 2 (2-2018)
Abstract
Background: Various chemical, physical and biologic treatment methods are being used to remove nitrogen and phosphorus from wastewater. Sequencing batch reactor (SBR) is a modified activated sludge process that removes phosphorus and organic material from sanitary wastewater, biologically.
Methods: This study was conducted in 2016.The performance of an aerobic-anaerobic SBR pilot device, located at Ahwaz West Wastewater Treatment Plant, Ahwaz, southern Iran in phosphorus and organic material removal was evaluated to determine the effect of the aerobic-anaerobic step time on the efficiency of nitrogen and phosphorus removal, the effect of changing the sequence of steps and the effect of time ratio on phosphorus removal efficiency. A reactor of 8 L was used. Influent contained 397 and 10.7 mg/l COD and phosphorus, respectively. The pilot plant started with a 24 h cycle including four cycles of 6 h, as follows: 1- Loading (15 min), 2-Anaerobic (2 h)-Aerobic (2 h), 3- Settling (1 h), Idleness (30 min) and 5- decant (15 min).
Results: After reaching steady conditions (6 months), Removal percentages of phosphorus, BOD5, COD, and TSS in The SBR over a period of 6 months was 79%, 86%, 89% and 83%, respectively.
Conclusion: Result of this study can be used for designing and optimum operation of sequencing batch reactors.
Fatemeh Amini Fard, Reza Jalilzadeh Yengejeh, Mansoureh Ghaeni,
Volume 13, Issue 2 (5-2019)
Abstract
Background: Due to the high content of nitrogen in the municipal wastewaters, this study evaluated the efficiency of Scenedesmus as an important microalgae in the removal of nitrate from wastewaters and its application as an appropriate culture medium. As algae have high resistance to temperature and pH changes, they can absorb low concentrations of nutrients and need simple low-cost technology. Through photosynthesis, microalgae effectively stabilize carbon dioxide at a low cost, and the oxygen produced by the photosynthesis process can reduce the biochemical oxygen demand (BOD) of wastewaters.
Methods: In this research, the chemical oxygen demand (COD), BOD, pH, total nitrogen (TN), and microalgae density were measured in the samples within 14 days after sampling from the inlet and outlet of municipal wastewaters treatment plant.
Results: The results showed that nitrogen removal rate from the wastewaters at the laboratory conditions was 93% in the inlet and 85% in the outlet, which are higher in efficiency than those provided by other treatment processes.
Conclusion: The microalgae can be used for the removal of nitrate and the production of algae biomass in municipal wastewaters processes before entering the natural environment.
Majid Ebadi, Ali Asareh, Reza Jalilzadeh Yengejeh, Najaf Hedayat,
Volume 15, Issue 1 (1-2021)
Abstract
Background: Highly-concentrated phosphate and nitrate anions from sugarcane wastewater are often discharged into public waters without standardized treatments. This study assessed the effects of electrical coagulation, initial pH and reaction time in the removal of phosphate and nitrate pollutants.
Methods: We used aluminum electrodes to remove the pollutants at Hakhim Farabi Agricultural and Industrial complex, Khuzestan Province, Iran. A septic tank was used for collecting water samples followed by measuring the pH, and the concentrations of phosphate and nitrate in the samples. The pH was set at 5, 7, 9 or 11. Six aluminum electrodes were placed perpendicular to the water flow and were connected to power in a single-polar method. They were used to assess the effects of pH changes, electrical power at 10 and 30 volts and the water retention time at 15, 30, 45 or 60 min. on the efficiency of the pollutants’ removal.
Results: The results indicated that under equal retention time and varying pH values, as voltage increased from 10 to 30, the phosphate and nitrate removal increased progressively. It was further demonstrated that the maximum phosphate removal efficiency was achieved at pH7, while it declined at higher pH levels. The highest possible nitrate removal efficiency was achieved under alkaline pH levels. The overall results showed that at every pH and voltage, the percentage of phosphate and nitrate removal increased over time.
Conclusion: This study demonstrated that electro-coagulation process is an appropriate and efficient method to remove phosphate and nitrate pollutants from sugarcane wastewaters.
Sahar Karami, Zahra Jiriaei Sharahi, Samaneh Koudzari Farahani, Sadra Solhi, Sayed Mohsen Hosseini,
Volume 17, Issue 2 (5-2023)
Abstract
Background: Membrane technology for water purification has gained much attention in many industries and for healthier human life. Also, improving the elimination of toxic heavy metals is a much needed strategy for the filtration of public water supplies. This study investigated the removal of toxic heavy metals from wastewater, using a novel thin-film membrane.
Methods: We investigated the structural, physico-chemical, and antifouling properties of the membrane, and its ability to remove toxic elements from water. Seven parameters were examined: Contact angle, water ionic contents, Fourier’s transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), 3D-surface imaging, water flux, and antifouling effects.
Results: The results indicated that a thin-film layer formed on the membrane. The 3D-images demonstrated that the surface roughness decreased when the polyaniline ratio to nanoparticles increased. The surface hydrophilicity increased by incorporating polyaniline into the surface. The water flux increased from 8.04 (L/m2.h) to 14.74 (L/m2.h) in the virgin membrane. The sodium sulfate rejection was 61% for the virgin membrane whereas it was >67% in the thin-film coated membrane. The data demonstrated excellent anti-fouling properties for the novel membrane, with a flux recovery ratio of >94.65% while it was about 79% for the virgin one. The rejection rates of chromium and copper ions for the novel membrane were >86% and >84%, respectively. These values were significantly higher than those of the virgin membrane (>53% and >51%).
Conclusion: The thin-film composite membrane significantly improved the removal rate of toxic heavy metals from the wastewater samples compared to the virgin membrane.
