Valorization of waste activated sludge: biohydrogen production and recovery of volatile fatty acids

Abstract

Over the course of the industrial revolution, over 80% of the world's energy has been produced by burning fossil fuels. Moreover, over the past 10 years, the global energy consumption has increased dramatically and is expected to do so for the next fifty years. Therefore, Energy is crucial for ensuring world development, and hydrogen, the cleanest sustainable energy source, has enormous promise. Thus, employing biological creatures like bacteria, algae, or archaea to produce hydrogen gas is a sustainable method known as bio-hydrogen production. Hydrogen is a clean, environmentally beneficial biofuel with several excellent features. In the research study, consortia of E. coli and E. aerogenes were used for the anaerobic fermentation of bio-hydrogen production and the VFA’s that were collected from the effluent were measured and used as a media for the photo-fermentation thereafter. Samples from Titagarh Sewage Treatment plants were collected and various parameters like pH, COD, TSS, TDS, VFA, ammonia, carbohydrate and ammoniacal nitrogen were calculated and based on these, fermentation were carried out thereafter. Also, nowadays VFA is an important platform chemical for biofuel, bioplastics, food and pharma industries. In our study, we have also recovered VFA from the wastewater effluent by adsorption on activated carbon and chemical precipitation by calcium salts and it was seen that adsorption has a better efficiency than precipitation in the recovery process. The recovered VFA can be used as a chemical in the future.