Solid-state anaerobic digestion (SS-AD) is a common practice for biogas production. Biogas constitutes a major part in the renewable energy production globally. In SS-AD, microorganisms consume the organic substrates present in the waste and convert it to biogas which consist of methane mainly. Different types of solid waste are used in SS-AD like food waste, municipal waste, agricultural waste which makes SS-AD a suitable process for waste treatment. SS-AD requires small capacity reactor with lower energy utilization in heating. It generates digestate which is very easy to handle and can be used as fertilizer since its rich in nutrients. Present study has discussed SS-AD, its working and operating process classification. Operational parameters define stability and efficiency of any process; therefore, operating parameters are discussed as well like nutrients, feed stocks, pH, temperature, C/N ratio, inoculums, inhibitors, and mixing and feedstock-inoculum ratio. Improvement in the biogas production strategies includes co-digestion, additives, and feedstock treatment methods. Latest strategies like the use of genetic engineering, and molecular biology tools are discussed as well.

Kabul, the capital city of Afghanistan is facing the serious problem of scarcity of water. Over-exploitation of the groundwater and the contamination of water are adding to the problem. There are poor management and misuse of water due to instability and the long war in the country. A chain of a large number of shallow wells is created to meet the requirement of rising population. It led to the over-exploitation of groundwater and the water table is declining very fast. Some of the existing wells are already dried. The grave situation can be imagined by the fact that around 85% of the population of the city is dependent on groundwater sources particularly hand pumps installed by individual households. Another problem of the city is the contamination of groundwater resources due to lack of a sewage system and treatment before its disposal. This paper elaborates the current status of water resources in terms of availability and its quality. Basin boundaries of water systems do not follow the administrative boundaries. Hence, cooperation and commitment at local, national and international levels, among various institutions, and organizations are needed to manage the looming water crisis in the capital of Afghanistan. This paper stresses the need for city-specific water policy for effective management of water resources. Population growth regulation in water-scarce areas is also required to contain the impact of the water crisis. The water policy will ensure environmental sustainability, enhanced productivity, groundwater recharge and biodiversity.

The leachate released from dumpsites can cause severe contamination of land and water. By studying seasonal variations of leachate characteristics generated from three active landfill sites of Delhi (India), it was found that seasonal variations can significantly affect the composition of leachate. Various parameters, such as conductivity, total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total Kjeldhal, ammoniacal nitrogen, organic nitrogen, heavy metals, chlorides and sulfates, are being released throughout the year beyond the prescribed disposal limit. It has also been seen that substantial quantities of industrial and other hazardous waste materials are also being dumped into the landfills. One can also find significant amounts (much above the permissible disposable limits) of substances such as TDS, COD, BOD, chloride, cyanide, and as in the inland surface waters. Already, the existing landfills are chocked much beyond their receiving capacity. Hence, if more waste matter is dumped in such places, it would only lead to releasing more hazardous leachate substances for a longer duration. This study will provide an in-depth analysis of leachate quality in three active landfill sites in the city of Delhi. This would enable the concerned authorities to install more effective seasonal-specific leachate management facilities at such landfills.

A simpler cost-effective method for the isolation of magnetically separable 'self-doped iron oxide nanocarbons' (FeO-NC) from waste printer ink (used as a carbon source material which is available free of cost) is discussed here. The process involves carbonization of waste printer ink in a muffle furnace at similar to 600 degrees C to obtain FeO-NC. The as-prepared FeO-NC has been investigated as an efficient heterogeneous catalyst for the long-known important organic reaction involving transformation of styrene to benzaldehyde in a quantitative yield (similar to 70%). Importantly, FeO-NC were magnetically separable along with good recyclability, which supports the sustainability of reported process. (C) 2020 Elsevier Ltd. All rights reserved.

Increasing landfill sites leads to serious environmental problems due to the generation of leachates. Leachates are the potentially hazardous waste from landfill sites and consist of many organic and inorganic, dissolved suspended, biodegradable or non-biodegradable matters. In this chapter, we are discussing various process involved during landfill biodegradation, generation of leachate and factor affecting biodegradation process. Microbes played an important role in the biodegradation and bioremediation of landfill waste and leachates. The different kind of microbes used organic material present in landfill and leachate for their metabolic activities and resulted in the production of gases like CH4 and CO2. The biodegradation processes of waste material depend on the various factors including characteristics of waste materials, moisture content, temperature, pH and the presence of inhibitors.

Numerous traditional methods are available for the conversion of waste to energy (WTE) such as incineration, anaerobic digestion, pyrolysis, gasification. Most of them suffer from low efficiency and high energy requirements. Microbial fuel cell (MFC) technology is an excellent alternative for the generation of renewable and sustainable energy and has the potential to help alleviate the current global energy crisis. The total wastewater generated in India is almost 250% of the total treatment capacity, and the Government is, therefore, looking for a sustainable solution for the treatment of waste. Indian population consumes around 700 billion cubic meters of water annually, and this figure will rise to 950 and 1422 billion m(3) by 2025 and 2050 respectively. Although treatment of wastewater is a serious concern, the energy recovery potential of wastewater has not yet been fully developed. A survey has been conducted through this study, and it was estimated that MFC technology has the potential to generate around 23.3 and 40 Tera Watt (TW) power by 2025 and 2050 by treating wastewater generated throughout India (urban areas) if utilized properly. This review article presents a various aspect of MFC technology for a proper understanding by the readers. This will be a unique study wherein the energy recovery potential of the wastewater produced in the Indian subcontinent has been estimated through MFC technology. A number of factors affecting the performance of MFC such as electron losses, reactor configuration, and varying concentration must be taken into account to augment output energy. The article summarizes an extensive literature survey of some selected papers published hi the last decade.

The abysmal state of and challenges in municipal solid waste management (MSWM) in urban India is the motivation of the present study. Urbanization contributes enhanced municipal solid waste (MSW) generation and unscientific handling of MSW degrades the urban environment and causes health hazards. In this paper, an attempt is made to evaluate the major parameters of MSWM, in addition to a comprehensive review of MSW generation, its characterization, collection, and treatment options as practiced in India. The current status of MSWM in Indian states and important cities of India is also reported. The essential conditions for harnessing optimal benefits from the possibilities for public private partnership and challenges thereof and unnoticeable role of rag-pickers are also discussed. The study concludes that installation of decentralized solid waste processing units in metropolitan cities/towns and development of formal recycling industry sector is the need of the hour in developing countries like India.

Air, water and soil contamination is the major source generated from municipal solid wastes. In current scenario air, water, and soil are polluted because of the uninhibited decomposition of solid wastes. The systematic treatment of municipal solid wastes leads to the economical source of energy. Appropriate municipal waste management (MSW) strategy be implemented to minimize environmental impact and subsequent energy recovery. In this mini review report we have discussed about the technological aspects of energy production from MSW. Overall energy potential and future prediction has also been reported.

Four organotin(IV) complexes of dihydrobis(2-mercaptothiazolinyl)borate were synthesized and characterized by elemental analysis and spectroscopic techniques (IR, 1H-NMR, 13C-NMR, 11B-NMR, and 119Sn-NMR). All the compounds were screened against bacterial, fungal, and cyanobacterial strains. Among the complexes, triorganotin(IV) complexes show better inhibition growth as compared to diorganotin(IV) complexes.

Potassium hydrotris(2-mercaptobenzathiazolyl)borate (KL) was formed by the solid state reaction of potassium borohydride and 2-mercaptobenzathiazoline. This ligand was reacted with R(n)SnCl(4-n) (R = methyl, butyl and phenyl, n = 2 and 3) in dichloromethane and four different neutral organotin(IV) complexes were obtained. All compounds were characterized by elemental analyses, FT-IR and multinuclear NMR ((1)H, (13)C, (11) B and (119)Sn) spectroscopy. Spectroscopic data indicate the six-coordinated nature of tin in its di and triorganotin(IV) complexes.To check the toxic potential of the ligand and its organotin(IV) complexes, selected bacterial (E. coli, S. epidemidis and S. dysenteriae) and fungal (A. niger, C. albicanes and A. flaves) species were screened. The results were compared with standard drugs kinamycine and miconazole for bacterial and fungal activity, respectively. The toxicity of the organotin(IV) complexes depends on the number and nature of organic groups attached to the tin atom; triorganotin(IV) complexes exhibit better inhibition than diorganotin(IV) complexes. All compounds were also screened on the cyanobacterial strains (Aulosira fertillissma, Anabaena variabilis, Anabaena species and Nostoc muscorum). Results show that the compounds inhibit the growth of organisms at very low concentration.

An oxo-homoscorpionate ligand [potassium bis(phthalato)borate] (KL) was prepared by solid state reaction of potassium borohydride and phthalic acid (1 : 3 molar ratio). The ligand is uninegative and can be a bi, tri and tetra-dentate chelating agent. The di- and tri-organotin(IV) complexes of this ligand are formed by replacement of chloride in R2SnCl2 and (R = methyl, butyl and R′ = phenyl and butyl). The ligand and all its complexes were characterized by elemental analyses and spectral studies (IR, 1H, 13C, 119Sn NMR and ESI mass spectra). Spectroscopic data reveal that all the complexes are hexacoordinate; the diorganotin complexes have trans octahedral geometry while the triorganotin complexes are distorted octahedral geometry. The toxicity of these organotin(IV) derivatives on selected microbes was considered. The compounds exhibit antibacterial (Bacillus anthracius and Escherichia coli) and antifungal (Candida albicans and Penicillium italicum) activities in vitro. The ligand shows less toxicity towards the microorganisms and its toxicity significantly increased after complexation with organotin(IV). Triorganotin derivatives (R3SnL) of the ligand are more effective compared to diorganotin derivatives (R2SnL2).

We investigated the antibacterial activity of some new steroidal thiosemicarbazone derivatives, prepared from the reaction of cholest-5-en-7-one with thiosemicarbazides, in ethanol in the presence of a few drops of HCl at 80 degrees C in high yield. All the compounds have been characterized by means of elemental analyses, IR, 1H NMR and mass spectroscopic data, to find an effective antibacterial agent. The antibacterial activity was first tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) of compounds was determined. The results showed that the steroidal thiosemicarbazones derivatives inhibit growth of both types of the bacteria (Gram-positive and Gram-negative). The acetoxy and chloro derivatives of cyclopentyl and cyclohexyl amine thiosemicarbazones were found to have more antibacterial activity than the other derivatives.

A heteroscorpionate ligand, potassium hydrobis(benzoato)(salicylaldehyde)borate (KL), has been synthesized. This was converted into organotin complexes R 2 SnL 2 and R 3 SnL complexes by mixing and stirring with a methanolic solution/suspension of organotin chloride. The ligand and its complexes were characterized by elemental analyses and spectral studies (IR, 1 H NMR, 13 C NMR, ESI mass spectra and Thermo gravimetric analysis (TGA)). Antibacterial and antifungal studies of these compounds were evaluated by the disc diffusion method at variable concentration against three species of bacteria ( Staphylococcus aureus, Klebsiella pneumonia and Bacillius subtillis ) and two species of fungi ( Asperjillius fiavus and Candida albicans ). It was found that triorganotin derivatives (R 3 SnL) of the ligand were more effective as compared with diorganotin derivatives (R 2 SnL 2 ). The organotin complexes of borates were tested for their algicidal activity on the cyanobacterial strains Aulosira fertilissma, Anabaena species, Anabaena variabilis and Nostoc muscorum and showed high to moderate toxicity towards the above species. The ligand and its complexes were also tested for its pH effect on soil in vitro for a duration of more than one month and it was found that they are able to kill pests without damaging the soil quality. Copyright © 2006 John Wiley & Sons, Ltd.

The inheritance of petaloidy along with plant height and maturity was studied in two crosses of pea, taking Early December (Petaloid) as male and two normal flower-late maturing varieties, 479 B and 172 M as females. Monogenic factor pairs governed the expression of petaloidy and plant height. The normal flower condition was dominant to petaloid. The symbol ‘Pst’ was proposed for the gene controlling petaloidy. A digenic F2 ratio of 12 late: 3 medium: 1 early was obtained for maturity. Joint segregation of characters revealed that all the four genes governing three characters were independent of one another. Pod deformity and style number were pleiotropically controlled by the gene ‘Pst’.