Engineering low-cost, low-energy decentralized anaerobic wastewater treatment processes by guided evolution of microbial communities

It is estimated that today as many as 2.4 billion people live without access to improved sanitation with rural areas home to 7 out of 10 people living without access. The prevailing paradigm of energy and water intensive centralised wastewater treatment (WWT) systems typified in the Global North renders current technologies not only unsuitable for address of the sanitation crisis experienced by the rural poor, but is increasingly recognised as unsustainable even in energy and water rich economies. As such, there is an urgent need to develop low-cost, low-energy decentralized wastewater treatment systems. Anaerobic digestion (AD) is a biological treatment process enabling stabilisation of wastes by removal of organics from the waste stream. Further,
AD has the potential to operate with a net energy gain as anaerobic microbes convert organics to methane gas, a readily storable form of renewable energy. However AD processes are notoriously fickle in the treatment of variable waste streams, so much so, that even in the Global North where centralisation provides a degree of redundancy in the wastewater infrastructure, AD is rarely if ever applied to the treatment of raw sewage. Recent advances in molecular biology are now enabling new insights to the complex microbial communities found in WWT systems. Many published studies point to the importance of the seed community in relation digester colonisation, and hence to the efficiency and stability of biological processes. Yet to date, no rational methodology exists to optimise microbial community composition in the the seed sludge for AD technologies. This project aims to couple application of 'WASTEBOT', a novel robotics platform developed at UoG, with an environmental 'omics approach to evolve and characterize optimal microbial communities for use as seed sludge in AD. The efficacy of the optimized seed communities to deliver robust and predictable treatment will be tested in-situ in novel household-scale digesters serving rural communities in both
the global south in collaboration with Asian Institute of Technology in Thailand, and, in the global north via collaboration with Scottish Water. If successful, the optimization procedure has potential to improve confidence across a range of low-cost, low-energy digester types and thus deliver much needed solutions to the sanitation crisis.