Hydrochemische Grundwasserkartierung von Taebriz/Iran und Umgebung

Copy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Development Of An Entropy- Based Fuzzy Eutrophication Index For Reservoir Water Quality Evaluation

Eutrophication phenomenon is one of the most common water quality problems in reservoirs in many regions. Determining the trophic status of the reservoirs is not a precise process and contains vagueness. Fuzzy set and entropy theories are concepts which can model uncertainty and imprecision in the data and the analysis. In this study, an Entropy-based Fuzzy Eutrophication Index model has been developed for classification of trophic level of Satarkhan Reservoir in the north-western part of Iran. Through the Fuzzy Synthetic Evaluation technique, trophic levels were considered as fuzzy sets and a fuzzy evaluation matrix was formed by defining the membership function of water quality indicators. The indicators were weighed by integrating both objective and subjective criteria. In this regard, the entropy method was used to determine the objective weights of the indicators based on the amount of useful information available in the data set and the subjective weight was determined by the analytical hierarchy process using a pairwise comparison done by the expert judgment. Classification of the trophic status of the reservoir was determined by multiplying the weighed vector by the fuzzy evaluation matrix. The results showed that critical months for eutrophication in Satarkhan reservoir occur in autumn and spring after the overturning phenomena. The strength of the results of developed entrophy-based fuzzy entrophication index is that the trophic level in each month was expressed with a degree of certainty. Also due to the ability of the model to integrate different kinds of objective and subjective quality observations considering the information included in the data, the proposed model is more robust than the previous index models such as Trophic Status Index and fuzzy trophic index

Development Of An Entropy- Based Fuzzy Eutrophication Index For Reservoir Water Quality Evaluation

Eutrophication phenomenon is one of the most common water quality problems in reservoirs in many regions. Determining the trophic status of the reservoirs is not a precise process and contains vagueness. Fuzzy set and entropy theories are concepts which can model uncertainty and imprecision in the data and the analysis. In this study, an Entropy-based Fuzzy Eutrophication Index model has been developed for classification of trophic level of Satarkhan Reservoir in the north-western part of Iran. Through the Fuzzy Synthetic Evaluation technique, trophic levels were considered as fuzzy sets and a fuzzy evaluation matrix was formed by defining the membership function of water quality indicators. The indicators were weighed by integrating both objective and subjective criteria. In this regard, the entropy method was used to determine the objective weights of the indicators based on the amount of useful information available in the data set and the subjective weight was determined by the analytical hierarchy process using a pairwise comparison done by the expert judgment. Classification of the trophic status of the reservoir was determined by multiplying the weighed vector by the fuzzy evaluation matrix. The results showed that critical months for eutrophication in Satarkhan reservoir occur in autumn and spring after the overturning phenomena. The strength of the results of developed entrophy-based fuzzy entrophication index is that the trophic level in each month was expressed with a degree of certainty. Also due to the ability of the model to integrate different kinds of objective and subjective quality observations considering the information included in the data, the proposed model is more robust than the previous index models such as Trophic Status Index and fuzzy trophic index

Solidification/Stabilization of Heavy Metals from Air Heater Washing Wastewater Treatment in Thermal Power Plants

In the present investigation, for the first time in Iran, dewatered sludge waste from air heater washing wastewater treatment of a thermal power plant was subjected to investigation of the cement base stabilization and solidification experiments in order to reduce the mobility of heavy and other hazardous metals as well as increasing the compressive strength of the solidified product for possible reuse of the waste. The solidification was done with two cement based mix designs with different waste/cement ratio is different samples. The results of leaching test on the solidified samples revealed that regarding the sand-cement mixture even with 25% waste/cement ratio, the leaching of heavy metals has completely been controlled up to 95%. In cement stabilization process the leaching of V, Ni, Zn and Cr could be decreased from 314.1, 209.1, 24.8 and 5.5 mg/L respectively in the raw waste to 6, 32.1, 3.6 and 3.6 mg/L in a mixture with 20% waste/cement ratio. During stabilization with cement-sand, the TCLP leachate contents of mentioned metals have been decreased to 4.2, 16.2, 2.5 and 2.2 mg/L with waste/cement ratio of 20%. X-ray diffraction studies showed that portlandite, calcite, lime, larnite and quartz have been shaped during the stabilization process. The compressive strength test results revealed that in both mixture samples, decreasing the compressive strength with increasing the amount of waste content in the mixture occurs. In sand-cement solidified samples with waste/cement ratio 25% and in cement solidified samples with waste/cement ratio 20%, a 40% decrease occurs in the compressive strength in comparison with the waste free mixtures

Enhancing Wastewater Treatment Efficiency Using MBBR: A Media Selection Approach

Background: Wastewater treatment is a critical environmental challenge, and moving bed biofilm reactor (MBBR) technology is an effective solution. The selection of appropriate biofilm media significantly impacts treatment efficiency, particularly in terms of organic matter and nutrient removal. This study aims to optimize media selection for MBBR systems to improve wastewater treatment. Methods: Three biofilm media types-K3, MB3, and K5-were evaluated based on key properties such as specific surface area (SSA), porosity, buoyancy, and economic feasibility. The analytical hierarchy process (AHP) was employed to assess and prioritize these criteria. Expert Choice software facilitated the analysis, followed by a laboratory-scale investigation to assess pollutant removal efficiency. Results: K5 media outperformed K3 and MB3 in terms of nitrogen removal (90%), chemical oxygen demand (COD) reduction (90%), biochemical oxygen demand (BOD) elimination (95%), and TSS removal (89%). K5 also demonstrated superior efficiency in pollutant removal while maintaining consistent pH regulation. K3 and MB3 displayed relatively lower performance, especially in nitrogen and COD removal. Conclusion: The study confirms that K5 media, selected using the AHP method, provides the highest treatment efficiency in MBBR systems. The AHP-based media selection process enhances the decision-making process, ensuring that economic and performance factors are adequately considered. Future studies should focus on scaling up the MBBR system with K5 media to further evaluate its long-term performance in real-world conditions

Solidification/Stabilization of Heavy Metals from Air Heater Washing Wastewater Treatment in Thermal Power Plants

In the present investigation, for the first time in Iran, dewatered sludge waste from air heater washing wastewater treatment of a thermal power plant was subjected to investigation of the cement base stabilization and solidification experiments in order to reduce the mobility of heavy and other hazardous metals as well as increasing the compressive strength of the solidified product for possible reuse of the waste. The solidification was done with two cement based mix designs with different waste/cement ratio is different samples. The results of leaching test on the solidified samples revealed that regarding the sand-cement mixture even with 25% waste/cement ratio, the leaching of heavy metals has completely been controlled up to 95%. In cement stabilization process the leaching of V, Ni, Zn and Cr could be decreased from 314.1, 209.1, 24.8 and 5.5 mg/L respectively in the raw waste to 6, 32.1, 3.6 and 3.6 mg/L in a mixture with 20% waste/cement ratio. During stabilization with cement-sand, the TCLP leachate contents of mentioned metals have been decreased to 4.2, 16.2, 2.5 and 2.2 mg/L with waste/cement ratio of 20%. X-ray diffraction studies showed that portlandite, calcite, lime, larnite and quartz have been shaped during the stabilization process. The compressive strength test results revealed that in both mixture samples, decreasing the compressive strength with increasing the amount of waste content in the mixture occurs. In sand-cement solidified samples with waste/cement ratio 25% and in cement solidified samples with waste/cement ratio 20%, a 40% decrease occurs in the compressive strength in comparison with the waste free mixtures