Fly ashHeavy metals Leaching Leachate Slag a b s t r a c t Fly ash and slag leachate pollution can be of great environmental concern due to generation of these wastes in huge quantities from their respective industrial units, mainly coalbased thermal power plants and iron and steel plants. For simulation of natural leaching in laboratory, various leaching methods are available, but selection of a method that can exactly simulate the real-life scenario for accurate estimation of various pollutants is challenging; particularly, the heavy metals present and impact due to reuse or disposal of these wastes. For choosing the most suitable leaching method according to specific situation, one must primarily consider the chemical and physical properties of wastes, the composition of the source, age of waste disposal, and the climatic conditions of the disposal area. Since these factors may not be specified, a variety of leaching methods with relevant equipment have been proposed by researchers; that are based on their required information to particular conditions in absence of a prescribed protocol and non standardization of equipment. The present review is an attempt to investigate the suitable leaching method for coal fly ash and slag.

Rapid industrialisation and resulting industrial solid waste from power plants and integrated iron and steel industries, have imposed an enormous environmental pressure on water resources of Chhattisgarh, a state in Central India. Rural population living nearby the study area is mainly depended on the available surface water in the form of lakes or pond in their vicinity. Therefore it is necessary to look after the surface water through leachate pollution caused by dumping and disposal of industrial solid waste. In the present study, ten surface water samples each for pre monsoon and post monsoon were collected for analysis from the surrounding areas of a major industrial region of Chhattisgarh. The AAS analysis of the surface water samples shows higher concentration of certain heavy metals above the permissible limits. In the pre monsoon samples the metals Mn and Cr resulted higher concentration and at the same time metals; Cu, Fe and Pb resulted in lower concentrations. Similarly, for the post monsoon samples, Mn, Cr and Fe found with higher concentration, while Cu and Pb resulted with lower concentration. The high amount of heavy metals were found in the analyzed samples shows that there is a real risk for population living in the nearby areas of the industrial region of Chhattisgarh. Therefore a huge amount of industrial wastes produced needs a proper disposal. Unscientific and poorly-managed disposal of industrial solid wastes containing heavy metals needs remediation before discharging into the environment.

As per the World Health Organization 80% of wastewater is released to the environment without satisfactory treatment. Constructed Wetlands (CWs) are one of the natural wastewater (WW) treatment methods. CWs have been recommended as a low technology, low maintenance, low operation cost, and green technology wastewater treatment system. Many types of CWs are currently in use. This paper studies these different types based on the climate, area, base materials, temperature, contaminant removal efficiency, removal mechanism and physicochemical analysis of various wastewater parameters. It is found that wetlands are successful in removing organic matter–Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD) and suspended solids and nutrients–total Nitrogen (TN) and total Phosphorus (TP). CWs need to be studied as a promising solution not only for effective treatment of wastewater but also as an economical method to improve the fertility of soil. Further, the paper discusses the scope of future research in CW to further improve the wastewater treatment technology.

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The present study investigates the application of Multi Criteria Decision Modelling (MCDM) on batch anaerobic codigestion of kitchen food waste (FW) and the fresh septic tank sludge (STS) for robust output. The batch experiment was carried out at a temperature of 37 ± 2 °C.