Volume 24: Sustainable Energy Solutions for a Post-COVID Recovery towards a Better Future: Part VII

Feasibility of energy generation with biogas at the household level: assessing the impact of anaerobic co-digestion of waste activated sludge and food waste taking a Water-Energy-Food (WEF) Nexus approach Gabriel Hernandez-Robles, Daphne Gondhalekar

Abstract

The effects of anaerobic co-digestion at household level with waste activated sludge and food waste as co-substrates were studied in a GD-BMP test with mix ratio volatile solids basis of 20:80, 30:70, 50:50, 70:30 and 80:20 (WAS/OW) respectively. The results obtained were used to assess the feasibility of energy generation and the volume of each waste that can be treated. The highest specific methane yield calculated was of 431.31mLCH4/gVSadded from the 30:70 mix ratio sample with an RSD of 4.68%. It was hypothesized that the benefits of adding food waste will shift the C/N ratio leading to a potential coverage to reduce the energy demand from households by 50%. In addition, the benefits from a house scale SBR with microbubble aeration followed by SCSTR anaerobic co-digestor. Using the 30:70 mix ratio analyzed, a calculation to obtain the electrical energy that can be recovered from a single household resulted in a 30% reduction of energy coming from the grid. This paper reflects that biogas can be used as a replacement of fossil fuels, reducing the carbon dioxide footprint and the strong link to the WEF Nexus cycle, and discusses the implications.

Keywords anaerobic co-digestion, GD-BMP test, organic waste, waste activated sludge, co-generation, Water-Energy-Food (WEF) Nexus