Salman Zafar

Biogas is a valuable renewable energy source and a secondary energy carrier provided by anaerobic digestion of biodegradable organic materials. It can be used as a fuel in a number of ways. Methane (CH4) and carbon dioxide (CO2) are the main components of biogas, with other pollutants such as ammonia (NH3), water vapour (H2O), hydrogen sulphide (H2S), methyl siloxanes, nitrogen (N2), oxygen (O2), halogenated volatile organic compounds (VOCs), carbon monoxide (CO), and hydrocarbons present in varying amounts. H2S is a toxic and odorous compound formed by the anaerobic digestion of bio-solids and other organic materials, and it is also one of the pollutants in biogas. Hydrogen sulphide must be eliminated because it is toxic to human health, poisonous to process catalysts, and corrosive to machinery. Desulfurization, or the removal of hydrogen sulphide, is an integral part of biogas utilization efficiency. The conventional desulfurization technologies for biogas that are currently avai...

Waste management has become a major environmental challenge across the Middle East due to high waste generation rate, lack of disposal sites, and absence of a sustainable waste management strategy. The annual solid waste generation in the Middle East has exceeded 150 million tons with countries like Saudi Arabia, Kuwait, United Arab Emirates, Qatar, and Bahrain featuring among the world’s top ten per capita waste generators. Lack of legal and institutional frameworks has been a major stumbling block in the progress of waste management sector. In recent years, waste management sector has made steady progress in the region; however, concerted efforts are needed to make it at par with the developed countries.

Despite being an attractive technological option for solid waste management, incineration-based processes for municipal solid waste (MSW) treatment are a subject of intense debate around the world. In the absence of effective controls, harmful pollutants may be emitted into the air, land and water which may influence human health and environment. Although incineration of municipal waste coupled with energy recovery can form an essential part of an integrated waste management system, yet strict controls are required to prevent its negative impacts on human health and environment.

Saudi Arabia has the potential to produce 1.6 TWh per year of electricity if all the plastics and other mixed waste are processed in RDF-based incineration plants. Around 3 TWh per year of power can be generated if all the food waste in Saudi Arabia is utilized in anaerobic digestion plants

India has a tremendous biomass potential which could easily be relied upon to fulfil most of our energy needs. An estimated 5 crore metric tonnes of liquid fuels are consumed annually in India, but with the actual biomass potential and its full utilization, India is capable of generating almost double that amount per annum.

As per Energy Statistics 2015, waste-to- energy potential in India is estimated to be 2,556MW, of which approximately 150MW (around 6 per cent) has been harnessed till March 2016. Despite the abundant waste-to energy potential, India’s progress in the field has been lethargic so far. Availability of land and funds is a major issue. Further, due to mismanagement, the waste collection is often inefficient and the deliveries are unreliable. The waste collected is often inaccurately segregated, which results in poor quality of waste, making it incompatible with the plants. Moreover, truck collections are sometimes
deliberately contaminated with industrial wastes to increase the supply’s weight and cost.

The biodiesel industry in India is still not developed despite the fact that demand for diesel is five times higher than that for petrol. The government’s ambitious plan of producing sufficient biodiesel to meet its mandate of 20 percent diesel blending is unrealized due to a lack of sufficient Jatropha seeds to produce biodiesel. Currently, Jatropha occupies only around 0.5 million hectares of low-quality wastelands across the country, of which 65-70 percent are new plantations of less than three years.

Environmental aspect of CSR is the duty to cover environmental consequences of a particular company's operations, products and facilities. The major ingredients of environmental sustainability are elimination of waste and emissions, maximizing energy efficiency and productivity and minimizing practices that may adversely affect utilization of natural resources by coming generations. Sustainability and carbon footprint occupies an increasingly important position on the corporate agenda around the world. Growing number of companies are realizing the importance of environmental initiatives in business development. Decrease in energy and raw material usage combined with reduced emissions and waste generation can tackle the environmental challenges facing the world. Leading IT companies, like Microsoft, Adobe, Apple and Google, are investing in renewable sources of energy that can generate power directly on-site. Clean manufacturing practices and energy-efficient design of equipment are also hallmarks of environmental sustainability. Let us take a close look at some of the major aspects of environmental sustainability. Eco-Friendly Packaging Packaging is an important concern for consumers, particularly those who are interested in converting to eco-friendly buying behaviors. Packaging plays a great role in environmental sustainability by protecting products, preventing waste and enabling efficient business conduct. Reduction in the amount of packaging and use of eco-friendly packaging material provide an attractive opportunity to promote environmental sustainability. Sustainable packaging is a relatively new addition to the environmental considerations for CSR. Companies using environment-friendly packaging materials are reducing their carbon footprint, using more recycled materials and minimizing waste generation. Companies that highlight their environmental initiatives to consumers can increase sales as well as boost product reputation.

The fermentation of whey by Kluyveromyces marxianus strain MTCC 1288 was studied using varying lactose concentrations at constant temperature and pH. The increase in substrate concentration up to a certain limit was accompanied by an increase in ethanol formation, for example, at a substrate concentration of 10 g L)1 , the production of ethanol was 0.618 g L)1 whereas at 50 g L)1 it was 3.98 g L)1. However, an increase in lactose concentration to 100 g L)1 led to a drastic decrease in product formation and substrate utilization. The maximum ethanol yield was obtained with an initial lactose concentration of 50 g L)1. A method of batch kinetics was utilized to formulate a mathematical model using substrate and product inhibition constants. The model successfully simulated the batch kinetics observed at S 0 ¼ 10 and 50 g L)1 but failed in case of S 0 ¼ 100 g L)1 because of strong substrate inhibition.

The fermentation of whey by Kluyveromyces marxianus strain MTCC 1288 was studied using varying lactose concentrations at constant temperature and pH. The increase in substrate concentration up to a certain limit was accompanied by an increase in ethanol formation, for example, at a substrate concentration of 10 g L−1, the production of ethanol was 0.618 g L−1 whereas at 50 g L−1 it was 3.98 g L−1. However, an increase in lactose concentration to 100 g L−1 led to a drastic decrease in product formation and substrate utilization. The maximum ethanol yield was obtained with an initial lactose concentration of 50 g L−1. A method of batch kinetics was utilized to formulate a mathematical model using substrate and product inhibition constants. The model successfully simulated the batch kinetics observed at S0 = 10 and 50 g L−1 but failed in case of S0 = 100 g L−1 because of strong substrate inhibition.

Kluyveromyces marxianus strain MTCC 1288 was employed to study the batch kinetics of ethanol and biomass production from crude whey. The yeast was able to metabolize most of the lactose within 22 h to give 2.10 g L−1 ethanol and 8.9 g L−1 biomass. The growth rate reached the peak value of 0.157 h−1 during the exponential phase but decreased significantly after the fermentation time of 12 h, presumably due to product inhibition. The specific ethanol formation rate attained the maximum value of 0.046 h−1 between 6 and 8 h of batch fermentation. The relationship between ethanol concentration and specific growth rate suggested a strong inhibitory effect of ethanol on the specific culture growth rate.