ABSTRACT

The large organic matter of solid waste such as garden and fruit waste offer great potential for biogas production. Anaerobic digestion of green waste-food waste mixture at thermophilic temperature range was carried out with the primary aim of investigating the effect of buffer (NaHCO3) and waste type in the digestion process, in order to initiate the digestion process.

Anaerobic digestion (AD) is a process by which microorganisms break down biodegradable material in the absence of oxygen. Anaerobic digestion can be used to treat various organic wastes and recover bio-energy in the form of biogas, which consists mainly of CH4 and CO2. A great option for improving yields of anaerobic digestion of solid wastes is the co-digestion of multiple substrates. Numerous studies demonstrate that using co-substrates in anaerobic digestion system improves the biogas yields due to positives synergisms established in the digestion medium and the supply of missing nutrients by the co-substrates. In addition, co digestion offers several possible ecological economical advantages. Recent research (published during the past three years) on this topic is reviewed in the current paper

 There was a digester tank of capacity 20 litre for decomposition of cow dung slurry and fruit waste. Two chemicals that are Na2Co3 and NaOH was used to make the buffer solution. Urea was added to increase the production of biogas. The fruit waste is grinded properly in grinding machine so that the surface area of slurry is increased and material will easily decompose in short time. Physio-chemical parameters of these influent (on the starting day of digestion) and effluent slurries (after 30th day from starting) in terms of total solid, volatile solid, temperature, pH and Non volatile solid were tested.

Overall study reveals that ideal condition for the production of bio gas is that pH of influent slurry must be 6.8 which was obtain by using buffering chemicals and waste should be grinded properly so that they decompose easily. This work can solve the problems of kitchen waste management as well as bring the fulfilment of energy requirement in terms of Biogas and optimization of biogas.

The ultimate biogas was obtained from using chiku (Sapodilla in Spanish), papaya, banana, muskmelon and mango fruit wastes as substrate was used. NaHCO3 was added further in order to improve the yield of CH4. The volume of the digester was 20 litres. The solid waste of 9kg was used which comprised of 5kg Cow dung, 2kg Fruit Waste, 2kg garden waste and100 gm of  NaHCO3. The remaining space in the digester was filled with water.