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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Chemistry and Chemical Engineering
- نوع مقاله: Journal Article
- کلمات کلیدی: Ozone,reactor,sludge reduction,Oxidation of sludge,Yield coefficient
- چکیده:
- چکیده انگلیسی: The excessive biological sludge production is one of the disadvantages of aerobic process such as SBR. So the problem of excess sludge production along with its treatment , and disposal in aerobic processes in municipal and industrial waste water can be seen in many parts of the world even in our country . to solve the problem of excess sludge production , reducing in by oxidizing some of the sludge by Ozone is a suitable idea , thus reducing the biomass coefficient as well as the sewage sludge disposal. In this study, Two SBR reactors with of 20 liter being controlled by on-line system are used. After providing the steady state in the reactors, along the 8 month research sampling and testing parameters such as COD, MLSS, MLVSS, DO, SOUR, SVI, residual ozone and Yield coefficient were done. The results showed that during the solid retention time of 10 days the kinetic coefficient of Y and Kd was 0.58 (mg Biomass / mg COD) and 0.058 (1/day) respectively. At the next stage of research, different concentrations of ozone in one liter of the returned sludge to reactor were used to reduced the excess biological sludge production. The results showed that the 20 mg ozone per gram of MLSS in one liter of the returned sludge to reactor is able to reduce Yield coefficient from 0.58 to 0. 28 (mg Biomass/mg COD),In other words, the biological excess sludge by 52 % .but the soluble COD increased slightly in the effluent and the removal percentage decreased from 92 in blank reactor to 64 in test reactor. While the amount of SVI and SOUR in this consumed ozone concentration reduced 9 mgO2/h.gVSS and 20 ml/g respectively. No sludge was seen in the 25 mg ozone concentration per gram of MLSS in one liter of the returned sludge to reactor.
- انتشار مقاله: 01-05-1387
- نویسندگان: Afshin Takdastan,Naser Mehrdadi,Ali Akbar Azimi,Ali Torabian,Gholamreza Nabi Bidhendi
- مشاهده
- جایگاه : پژوهشی
- مجله: Environmental Energy and Economic Research
- نوع مقاله: Journal Article
- کلمات کلیدی: children,Carcinogenic risk,Hazard index,Hazard Quotient,Adults
- چکیده:
- چکیده انگلیسی: Health risk assessment for heavy metals is a suitable technique to environmental planning. Accordingly, soil samples were obtained from three contaminated sites of Tehran Province, Iran. The heavy metals determined by ICP-AES, then health risks calculated for adults and children. The hazard quotient and hazard index values for all heavy metals and pathways were below a safe level in site 1, and all inhabitants were not at non-carcinogenic risk. The HQ of the ingestion pathway in adults and children for site 2 and site 3 were in the following order: Cd>Pb>Cu>Zn. As for adults and children in the three pathways, the HQ values for Pb, Cu and Zn were less than one, meaning that both the adults and children were not at non-carcinogenic risk. The HQ of the ingestion in adults, similarly, HQ of the ingestion and dermal in children for Cd were greater than 1 in 2 and 3 sites, meaning that the Cd was hazard for adults and children. The cancer risk has been calculated based on Pb and Cd. The US Environmental Protection Agency considers acceptable cancer risk within the range of 1×10−6 to 1×10−4. Though insignificant in its values, carcinogenic risk for adults in site 1 (2.722×10-4), site 2 (6.67×10-4) and site 3 (9.4444×10-4) and for children on site 1 (5.5×10-4), site 2 (2.203×10-2) and site 3 (1.94×10-3) have been higher than the acceptable values. Hence, the cancer risk for children were more than adults.
- انتشار مقاله: 23-01-1399
- نویسندگان: Fatemeh Akbarpour,Saeid Gitipour,Majid Baghdadi,Naser Mehrdadi
- مشاهده
- جایگاه : پژوهشی
- مجله: Environmental Energy and Economic Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Life cycle assessment,Sewage Sludge Disposal,Ekbatan Tehran Wastewater Treatment,OpenLCA,Eco Indicator 99
- چکیده:
- چکیده انگلیسی: The present study has assessed the life-cycle as an efficient method for environmental analysis, four disposal systems, and the management of urban sewage sludge in Ekbatan Tehran wastewater treatment plant. In order to assess the effects of the life-cycle Eco Indicator 99 method was used by OPENLCA software, and system boundary has been considered since the arrival of swage to wastewater treatment until its exit and the disposal of sludge. According to the results, using sludge in agricultural lands has positively influenced the group effect of fossil fuels due to economizing the production of phosphor and nitrogen fertilizers. On the other hand, using sludge in agriculture has negatively influenced the carcinogenetic group effects, Inorganics Respiratory, ecotoxicity, acidification, and fertilization, which is mainly due to the heavy metals in sludge. However, industrial fertilizers have some heavy metals. Therefore, comparing the effects of life cycle from two processes of using sludge and industrial fertilizer may be considered in decision making to select the optimal process.
- انتشار مقاله: 13-04-1399
- نویسندگان: Gholamreza Nabi Bidhendi,Morteza Rahmanzedeh,Hasan Hoveidi,Naser Mehrdadi
- مشاهده