Anaerobic co-digestion of sewage sludge and food waste

Abstract

Anaerobic co-digestion of organic matter improves digester operating characteristics and its performance. In the present work, food waste was collected from the institute cafeteria. Two types of sludge (before centrifuge and after centrifuge) were collected from the fluidised bed reactor of the institute treating sewage wastewater. Food waste and sludge were studied for their physico-chemical characteristics, such as pH, chemical oxygen demand, total solids, volatile solids, ammoniacal nitrogen, and total nitrogen. A biomethane potential assay was carried out to find out the optimum mixing ratio of food waste and sludge for anaerobic co-digestion. Results indicated that food waste mixed with sludge in the ratio of 1:2 produced the maximum biogas of 823 ml gVS(-1)(21 days) with an average methane content of 60%. Batch studies were conducted in 5 L lab-glass reactors at a mesophilic temperature. The effect of different substrate loading rates on biogas production was investigated. The mixing ratio of food waste and sludge was 1:2. A loading rate of 1 gVS L d(-1)gave the maximum biogas production of 742 ml g(-1)VS L d(-1)with a methane content of 50%, followed by 2 gVS L d(-1)with biogas of 539 ml g(-1)VS L d(-1) Microbial diversity of the reactor during fed batch studies was investigated by terminal restriction fragment length polymorphism. A pilot-scale co-digestion of food waste and sludge (before centrifuge) indicated the process stability of anaerobic digestion.

From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures

“…The positive effect of co-digesting organic matter with sewage sludge (e.g. food waste or energy grass) on the reactor performance has recently been reported [42, 43]. Moreover, the application of leachate in sewage digestion has been proposed too [44].…”

Anaerobic Digestion of Kitchen and Sewage Sludge Bio Waste to Biogas Using Engineered Bio Catalysis

“…The blended kitchen and sewage sludge bio waste had an average organic carbon loading content of 95% and this was a clear indication that the blended waste is an attractive option for biogas production due to the high organic composition. Prabhu and Mutnuri (2016) also reported a high organic rate of more than 80% when they investigated the potential of co-digesting kitchen waste and other organic waste. As the anaerobic digestion process increased, the organic carbon loading rate decreased significantly with increase in the digestion period by about 82% (Figure 2).…”

Optimizing the co-digestion supply chain of sewage sludge and food waste by the demand oriented biogas supplying mechanism

“…With the increase of newly built sewage plants, large amounts of excess sludge have been produced (Prabhu and Mutnuri, 2016). Anaerobic digestion (AD) has been regarded as a promising method for sludge stabilization, and the produced biogas can be used for electricity production as a renewable energy source (Glivin et al, 2016; Luo et al, 2019).…”