photo-biological hydrogen production and recovery of volatile fatty acids from waste activated sludge

Abstract

The demand for energy is rising primarily because of technological advances. Fossil fuels are unable to generate energy with such massive amounts. Renewably generated clean energy can address this problem. Hydrogen is an environmental friendly and clean fuel that may be utilised in combustion machines or fuel cells for generating power. Starch wastes from various industrial food processing wastes are easily accessible, which makes them a viable source for the production of hydrogen (H2). The production of H2 during the fermentation process is based upon various external bioprocess parameters, including pH, temperature, and light intensity; substrate type and concentration (simple sugar or complex carbohydrate), mixed or pure microorganism strain; mode of operation (batch, fed batch, or continuous), fermentation technique (dark or photo) and the design and configuration of the bioreactor. Among various processes, photo fermentation way of Bio-H2 production is thought to be one of the easy and cost-effective technique. Photo-fermentation is a potentially dynamic method that can utilise a range of feedstocks, such as the residues of dark fermentations, which can result in different two-stage system configurations, or different industrial and agricultural waste streams that are high in organic acids or sugars. This system’s metabolic and enzymatic characteristic are described, and potential waste streams for practical use are explored. The substrate in photo-fermentation technique was chosen as waste activated sludge which is produced in large amount in many water treatment plants around the country. The WAS is found to be reach in all type of nutrients needed for a bacterium to grow and able to produce gases. Purple non-sulphur bacteria were chosen to carry out the photo-fermentation process under proper illumination of light under anaerobic conditions. Different parameters were checked to enhanced the proper production of Bio-H2 in lab scale. We have followed simple water displacement method to collect the produced gas in a 250-ml measuring cylinder. At the end of 96 hrs we could find 250 ml of water to get displaced and assume that that much amount of gases was produced. When we tried to execute the process by using WAS as substrate then at the same time interval there was gas collected. Different microorganism presents in the WAS obstructed R. sphaeroides to ferment the substrate. Next step will be pre-treatment of WAS and run the same process to overcome the challenges and to able to produce Bio-H2 at an easy step.