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Advanced oxidation process in general and hydrodynamic cavitation, in particular, has emerged as a promising technology for the treatment of wastewater in the last few years as the process is energy-efficient and cost-effective. In this process, cavities are generated due to local pressure drops caused by constrictions. This work aimed to investigate the potential of hydrodynamic cavitation as a tertiary treatment to treat the secondary sedimentation tank effluent of a sewage treatment plant, with two laboratory-scale experimental setups having an orifice plate of a 1 mm diameter hole. The process dependency was estimated by optimizing inlet pressure (0.8 bar for setup I and 5 bar for setup II). Moreover, effective orifice jet length was varied to investigate the impact of fluid buoyancy force on expansion and collapse of a cavity on the chemical oxygen demand removal and disinfection potential. At L2 length (two-thirds of the original length), both setups can degrade the organic and inorganic pollutants to the maximum extent. With the optimum condition in setup II, maximum COD, TSS, and fecal coliform degradation were 80.47%, 62.83%, and 52.27%, respectively, compared to setup I. [ABSTRACT FROM AUTHOR]

The strength of municipal wastewater and sludge considering their potential for biogasification can be expressed in terms of multiple parameter comprehensive indices (MPCI), namely, Wastewater Comprehensive Index (WWCI) and Sludge Comprehensive Index (SCI), respectively. Both of these indices can be calculated using fuzzy multiple criteria decisions making (FMCDM). Simple linear equations are established to express the relation between these indices, suspended solids concentration and biogas. The linear equation is developed to predict biogas from multiple parameter comprehensive indices, which indicate the linear relation between strength of wastewater, sludge and biogas. Nomogram was developed to get immediate quantification of biogas by linear scaling of suspended solid concentration and multiple parameter comprehensive indices (MPCI). Using a linear equation obtained from regression analysis; a suitable scale was developed to construct the nomogram. The biogas was found 96% precise with reference to measured one when estimated using nomograms. A single parameter, that is, suspended solids concentration will be monitored at municipal wastewater treatment plant, by digital device; to save chemicals, time, power and human resource. While taking efforts toward smart cities; digitalization and resource conservation will be creditable. [ABSTRACT FROM AUTHOR]

Globally, over 50% of the population is urbanized as on today. As per World Bank's estimates, by 2045, the world's urban population will increase by 1.5 times to 6 billion. Cities are in focus primarily and the world has evidenced that cities are core to socio economic development of any nation. Cities also in perceived as source of threats for climate change. The attention on cities is not only for socio-economic development of any nation but also as potential to bring in disasters. Smart city concept is considered to be a novel model, to address both the issues balancing development and disaster prone characteristics of city, using technology. However, the taxonomy of smart cities varies through geographies. Government of India in 2014 selected 100 cities for transformation into smart cities in a mission mode through infrastructure development with an objective to improve quality of life of citizens, by use of technology. Many media have released ranking of smart cities but measure of smartness in a systematic & scientific approach has been limited. This study presents a framework of smart cities in India and suggests a methodology to assess smartness of cities under six broad dimensions using fuzzy multi criteria decision making (MCDM) technique. This model gives a comprehensive Smart City Index, which evaluates cities on the basis of multiple characteristics of a smart city including economy, governance, environment, mobility, living and people. The model assesses datasets across 31 factors for 4 cities of Gujarat, and smartness index was calculated for 4 cities of Gujarat state in India. The results presented gives an understanding on performance of the cities in various aspects and provides guidance to authorities to take corrective measures for improvement. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]