Ahmadreza Yazdanbakhsh; Mohammad Rafiee; Ghasem Kiani feizabadi
Volume 26, Issue 1 , March and April 2019, , Pages 109-118
Abstract
Background: Anoxic-oxic (A/O) is a new method of wastewater treatment and is being used in Mahdishahr wastewater plant. considering the lack of studies in this area, it seemed necessary to study the performance of A/O system in wastewater treatment. This study was carried out to evaluate the efficiency ...
Read More
Background: Anoxic-oxic (A/O) is a new method of wastewater treatment and is being used in Mahdishahr wastewater plant. considering the lack of studies in this area, it seemed necessary to study the performance of A/O system in wastewater treatment. This study was carried out to evaluate the efficiency of Mahdishahr wastewater Treatment Plant. Materials and Methods: The present cross sectional study was conducted in 2014 during 8 months. Sampling was performed two times per week from the incoming wastewater, aeration pond and effluent. Overall, 200 samples were collected. The efficiency of Treatment Plant was measured by TSS, BOD5, COD, MLSS, MLVSS, and SVI indices in aeration ponds based on standard method. Then the datas were analyzed by statistical analysis. Results: The mean concentrations of BOD5, TSS and COD in influent were 221.6 mg/l, 203.8mg/l and 321 mg/l respectively. The mean concentrations of BOD5, TSS and COD in effluent were 23.65 mg/l, 16.79 mg/l and 34.9 mg/l respectively. According to the results the average removal efficiency of BOD5, TSS and COD were about 87.25%, 91.77% and 87.29% respectively. These results are in accordance with standards of Iranian Department of Environment to be used for agricultural purposes. During the study, the monthly mean for SVI was 67.3 ml/g and the mean for MLSS and MLVSS was 1880 and 1182 mg/l respectively. Conclusion: in present study, the efficiency of A/O process in COD removals is approximately 89 percent, representing high degradability of wastewater in A/O reactor. In addition, according to the results this method was efficient and the effluent complied with Iranian standards in terms of COD, TSS and BOD5, thus the flow is suitable for reuse or discharge to water courses.
Fatemeh Adami ghamsari; Farzaneh Hosseini; Anita Khanaferi
Volume 22, Issue 4 , September and October 2015, , Pages 685-685
Abstract
Background & Objectives: Today, entrance of wastewaters, especially detergent and cleaner agent’s production industries wastewaters, to surface and underground waters is one of environmental pollution concerns. These wastewaters are containing detergents and surfactants, such as polysorbates ...
Read More
Background & Objectives: Today, entrance of wastewaters, especially detergent and cleaner agent’s production industries wastewaters, to surface and underground waters is one of environmental pollution concerns. These wastewaters are containing detergents and surfactants, such as polysorbates and, because of exposure of human and other organisms, their degradation is of great important. This research analyses degradation of a non-ionic detergent in polysorbate group called Tween 80 (polysorbate 80) and studies effect of pH and temperature on degradation rate of this detergent, using lipolytic bacteria (isolated from Tehran oil refinery wastewater and activated sludge). Materials & Methods: For primary isolating of lipolytic bacteria, the TSA medium containing Tween 80 and olive oil has been, separatively, used. Then specific culture Tween agar and Tributyrin agar have been used to study for lipase enzyme bacteria production. Also for confirmation degradation, instrumental methods, spectrophotometer and FTIR were used. Results: The results shows that the isolated bacteria are able to depredate polysorbate 80 by lipase enzyme production. Bacillus cereus was known as the best degradator after the identification of the molecular basis of sequencing 16S rRNA. Bacillus cereus ATCC 14579 (T), Pseudomonas aeruginosa and other Bacillus sp was known. Conclusion: The results showed that pH and temperature affects on the degradation of tween, and the Pseudomonas aeruginosa at acidic range of pH, two gram positive bacillus at alkali range of pH and three bacteria at 37 ˚C have the best degradation.
Reza Barati Reshvanloo; Abbas Rezaee; Hoshyar Hosseini; Hamidreza Tashyiee
Volume 21, Issue 4 , September and October 2014, , Pages 693-701
Abstract
Background: High nitrate concentration in water resources can create some diseases such as methemoglobinemia in children and environmental problems like eutrophication. Nowadays, different biological methods have developed for nitrate removal from water resources. This study aimed to examine ammonium ...
Read More
Background: High nitrate concentration in water resources can create some diseases such as methemoglobinemia in children and environmental problems like eutrophication. Nowadays, different biological methods have developed for nitrate removal from water resources. This study aimed to examine ammonium nitrogen removal via modified integrated fixed film activated sludge (IFAS) using multiwall carbon nanotubes.
Materials and Methods: The experiments were performed to evaluate efficiency of modified IFAS using carbon nanotube in laboratory scale with continues form. The effect of multiwall carbon nanotubes on sufficiency of process with retention time and ammonium concentration was studied.
Results: The results showed that applied multiwall carbon nanotubes in modified IFAS can lead to an acceleration in primary sludge production and ammonium removal from low and middle concentrations wastewater.
Conclusion: According to the obtained results, utilizing the multiwall carbon nanotubes as medium in an IFAS can improve the efficiency of the system for ammonium removal.