Deciding which are the best performing wastewater treatment plants can be complicated, as their operations comprise different parameters which are either dependent or non-dependent on each other, and are important when deciding the type of treatment. The relative importance of these parameters in terms of weight indicates the priority assigned by decision-makers to the criteria when ranking the alternatives. These weights are calculated by statistical relativity and Saaty's nine point scale. The sensitivity of both of these approaches is analyzed. The performance of six municipal wastewater treatment plants is evaluated using the Multi-criteria Decision Making (MCDM) Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). Efficiency is monitored on the basis of nine wastewater characteristics and compared with the limits established by the Central Pollution Control Board of India. The analysis uses both qualitative and quantitative approaches, which result in differential rankings; accordingly, plants with maximum organic loading removal efficiency were found to be most efficient when weights were applied as per Saaty's scale. The study proposes a field base approach with regard to the suitability of the weight allocation method for respective utilization of the fuzzy approach in environmental monitoring systems.

Multiple parameter comprehensive index by fuzzy logic is an innovative approach toward environmental indexing. An attempt was carried out to express strength of municipal wastewater and sludge considering their potential for biogasification in terms of wastewater comprehensive index (WWCI) and sludge comprehensive index (SCI), respectively. Both these indices were calculated using fuzzy multiple criteria decisions making (FMCDM). Further biogas was predicted using these WWCI and SCI by multiple linear regression. A significant relation was found in suspended solids concentration of influent wastewater and digester feedstock with WWCI and SCI, respectively. Considering this linear relation, an empirical equation was developed consisting WWCI and SCI giving biogas, which was found a user friendly and precise over established biogas prediction models. As both of these indices will be obtained simply by measuring suspended solids concentration by digital inline meter at wastewater treatment plant there will be no any need to practice laborious sampling, characterization, and calculations.

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Urbanization and industrialization with minimal focus on environmental pollution has resulted in rapid degradation of natural environment demanding a fresh look at the pollution control strategies. An attempt has been made to address the problem, and a viable procedure for ranking of industries based on their environmental pollution potential has been proposed. Vagueness in the perception of environmental experts for ranking the techno‐scientific parameters in linguistic terms for the specific usage coupled with imprecision in parametric data calls for the application of fuzzy modeling in this study. The formalized approach detailed in this article using fuzzy multicriteria decision making for ranking the industries is one of the important techniques in decision research. The case study discussed in this article relates to three dying and printing textile industries located in Surat, in the State of Gujarat, India. The feasibility of the proposed approach for ranking of the industries has been discussed. The approach detailed in this sequel might be considered as a small step in the formulation of appropriate environmental pollution control strategies. A commentary on pollution tax, stringent emission standards, and its effect on the ranking of industries with further research needs form an integral part of the article. © 2008 American Institute of Chemical Engineers Environ Prog, 2008

Reuse of greywater is the one of the alternative to fulfil the water demand. This study was carried out the efficiency of filter media for greywater treatment. The main aim of present study to develop the primary filter by using locally available media (i.e. jute coir rope, rise husk, pine wood pieces and marble stone). Greywater was collected from the Girls Hostel at SVNIT on regular basis. Filter performance was examined by maintaining the physico-chemical such as turbidity, COD and total solids. Filters were run for different retention time (i.e. 2h, 4h, 6h., 8h., and 16h.) in which at 8h RT, gives maximum removal efficiency. Filters used as primary filter so greywater applied directly and obtained results shows that all media remove impurities significantly Rice husk media shows maximum turbidity removal (66-81%) for different retention time. Than turbidity removal showed by jute coir rope (63-79%) followed by marble chips (53-73%) and pine wood (52-73%). COD removal in treatment by marble chips bed (34-59%) slightly greater than coir jute rope (41-52%), pine wood (31-51%) and rice husk (22-55%). Total Solids maximum removed by pine wood (21-48%) for all retention time examined. Effect of retention time also was monitored for all filters among the all media filters 8h retention time showed maximum removal efficiency in terms of impurities analysed.