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Hydrogen sulfide (H2S) is a precipitant used widely for metal recovery in metallurgical industries. A potentially low-cost method for producing H2S utilizes two waste products: municipal solid waste (MSW) and sulfate-rich wastewater. In this process, MSW serves as the electron donor and sulfaterich wastewater functions as an electron acceptor for sulfate-reducing bacteria (SRB) to produce H2S through the anaerobic respiration of SRB. The free liquid that is generated in a MSW landfill, referred to as leachate, has previously been tested as an electron donor for SRB. However, with high concentrations of recalcitrant organic carbon and biodegradable carbon typically scavenged by fermentative and methanogenic microorganisms, the use of leachate typically results in poor sulfate reduction rates. The liquor from the anaerobic fermentation of MSW (composed primarily of volatile fatty acids (VFAs)) could instead provide a more concentrated and readily available source of electron donors for SRB. Yet, the variability in the composition of organics within the liquor combined with the versatility of SRB and the presence of competitors for substrates results in poor predictions of sulfate reduction rates. Furthermore, the combined use of liquor from MSW fermentation (fermenter liquor) and sulfaterich wastewater would serve as an exemplar for using two locally available waste sources to produce a valuable resource of local demand. However, the high salinity of some sulfate wastewater streams, particularly in arid regions such as Australia, is found to make biological sulfate reduction less effective. Therefore, to explore the combined use of the two waste streams, the aim of this study was to examine the effectiveness of MSW fermenter liquor as an electron donor to be used with high salinity sulfate streams for biological H2S production. Studies have found that a limitation to using VFA mixtures as a feed to SRB cultures is that acetate is often not metabolized. As such, the capacity of different inocula to utilize all the fermentation products of MSW for sulfate reduction was investigated. The three inocula chosen for investigation were biofilm from a laboratory-scale reactor fed with sewage, sediment from a brackish mangrove, and sediment from a saline estuary. The salinities of the environments from which the inocula were sourced were maintained throughout the enrichment. The performance of each inoculum was evaluated for the extent that the chemical oxygen demand (COD) was utilized by SRB. The study found that the mangrove and estuarine inoculated reactors demonstrated higher sulfate removal efficiencies (80-88%) compared to the biofilm inoculated reactors (32-49%) as a result of the efficient use of COD. To explore VFA usage by sulfate-reducing cultures exposed to high salinity sulfate streams, the culture enriched from the estuarine sediment and hence grown under saline conditions of 20 g NaCl/L was subject to salinity increments of 7.5 g NaCl/L from 20 to 50 g NaCl/L. With a feed of ii synthetic fermenter liquor (VFA ...

Acid mine drainage (AMD) is one of the most important environmental problem faced by some of the coal and many metal mines which is required to be treated and managed in economical and efficient manner. The AMD is harmful for aquatic life and corrodes the pumps, pipes and machineries in the mines. The AMD problem originates from active mines, abandoned mines, coal waste spoils and stripped area. About 40% of the AMD pollution problems originates from active mines both surface and underground and rest from others. The discharged acidic water from the mines is detrimental to environment in general and water quality in particular, because if their high acidity, high metal concentration and high sulfate content. Lots of researches are going on throughout the worlds to tackle and minimize the problems of AMD in coal mines of USA, Canada, Australia and India. Therefore it requires neutralization up to acceptable limit. Now days, various treatment systems are available for treatment of AMD. Active treatment system is costly and requires continuous supervision, whereas passive treatment system is long process. The application of SAPS utilizes the advantage of active treatment system and passive treatment system. In present paper, an attempt has been made to highlight AMD generation and application of SAPS for treatment of AMD.

Acid mine drainage (AMD) is presently observed as one of the major water pollution problems in mining area throughout the world. Proper scientific management of AMD is essential for achieving the national goals for environmental norms. In this studyperformance of AMD treatment by laboratory successive alkalinity producing system (SAPS) by observing the effects of some metals and hydraulic retention time. In this study the experiments were conducted in laboratory successive alkalinity producing system (SAPS) with different synthetic AMDs for five Hydraulic retention times(HRTs). The successive alkalinity producing system shown the promising results during the AMD treatment. The effects of iron, aluminium and manganese were jointly investigated, whichshowed that Net alkalinity generation (NAG) increases with increase in influent metal contents. It was also observed thatNAG also showed increasing tendency with HRT during AMD treatment by SAPS. The obtained findings from this study can be applied for efficient design and operation of successive alkalinity producing system for AMD treatment process in mining industry.