Understanding how microbial communities respond to design and process engineering in wastewater treatment

点击翻译按钮获取中文摘要

Global human activity is responsible for the production of 105 billion tonnes of organic wastes per year. Organic waste sources include food waste, crop and animal residues (including manures) and sewage sludges from wastewater. The unsupervised decomposition of this material results in the release of substantial greenhouse gases (GHG) to the atmosphere. It has been estimated that extensive deployment of existing anaerobic digestion (AD) technologies for the biological treatment of organic wastes could reduce global GHG emissions by 10% by 2030 and produce 10,100 to 14,000 terawatt hours of energy. That is, 16-22% of global electricity consumption, or 26-37% of natural gas usage. Thus, AD could play a critical part in global efforts to reach Net Zero. AD is a bio-based technology that uses communities of hundreds of different species of microbes to recover resources from waste. The microbes found in anaerobic digesters facilitate the decomposition of organic materials into biogas, a mixture of carbon dioxide (CO2) and methane, two greenhouse gases that contribute to climate change. In contrast to fossil sources of these gases, the carbon liberated by AD comes from CO2 that has been recently fixed from the atmosphere by plants. By cycling CO2 fixed from the atmosphere rather than adding CO2 from fossil fuels, AD can be considered a Net Carbon Zero technology. The biogas generated by AD is usually captured before being burned to generate heat, electricity and Net Zero CO2, or upgraded to biomethane, sometimes referred to as Renewable Natural Gas, which can be injected into the grid as a Net Zero drop-in replacement for natural gas. Methane can be used as a building block for a range of important chemicals, including plastics, and so AD could potentially contribute to the displacement of fossil fuels for plastics and other products that are currently petroleum-based.Anaerobic digestion is the UK government's preferred disposal route for the 9.5 million tonnes per annum of domestic food waste. Segregated food waste collection legislation is due to be rolled out in the UK this year (2023) so that more resources can be recovered from waste more easily. In addition, UK water companies treated 801,721 tonnes of sewage sludge in 2021, a decarbonisation saving of 563,200 tonnes CO2 equivalent. There are numerous benefits to the work we propose to carry out with Yorkshire Water, which aims to reach Net Zero by 2030, with the primary impacts including:- Near-term solutions that can be deployed before 2025;- Providing medium-term options that can be planned for implementation over the five year Asset Management Period from 2025 (known as AMP8 or PR24 - the Ofwat 2024 Price Review that will consider whether Water Companies are performing as expected);- A long-term consideration of the opportunities offered by AD, including but not limited to: - recovery of volatile fatty acids (building block molecules) from sewage sludge for the production of bioplastics; - treatment of microplastics; - the future of wastewater treatment eg. genetic manipulation of biology to enable zero aeration (low energy) wastewater treatment in 10 years, wastewater treatment for carbon capture, and as an exemplar for biorefining.