Being a wastewater treatment specialist, I have often pointed out that more projects should be making use of waste by-products to generate renewable energy. Anaerobic digestion (AD) processes, which are widely used in wastewater treatment processes produce biogases. These are mainly methane and carbon dioxide gases, which are often wasted. In a recent paper McCarty et al. said that anaerobic treatment of wastewater offers the potential for wastewater treatment to become a net generator of energy, rather than the large energy consumer that it is today. The good news for the environment and the wastewater treatment industry in the north of England is that the European Investment Bank (EIB) announced that they have just approved a £400 million loan to the UK’s United Utilities for energy efficient water management, including generating green energy.
The loan will benefit 6.8 million people across Northwest England, through individual schemes to improve drinking water quality and enable more energy efficient treatment of wastewater. The funding will include support for projects that take into account the potential impact on water and wastewater of extreme weather events and climate variability over a 25-year period. The EBI has provided nearly GBP 3 billion to water companies across the United Kingdom in the past 5 years.
One of the projects to benefit from the funding is the £100m project at Davyhulme wastewater treatment works in Manchester, says the press release. The scheme will provide enhanced sludge digestion, resulting in a cleaner soil conditioner that can be recycled to farmland, plus large volumes of biogas that will be used to generate green energy via combined heat and power engines at the site. The electricity generated will be used to power the entire plant, one of the biggest in the UK, and any excess will be transferred into the National Grid.
Wastewater treatment plants at 12 locations will also be upgraded to generate heat and electricity through combined heat and power engines. The treatment capacity in two locations will be increased to meet local population growth and ensure compliance with new environmental standards.
The funding will also support flood alleviation schemes and programmes to improve water quality in rivers along the coastline by upgrading sewer overflow points and building 101 new storm water detention tanks.
United Utilities already uses AD technology to treat sewage sludge and generate electricity at a number of their large treatment plants across the North West. Blackburn is the first in East Lancashire to use a sustainable power supply to run its heating and machinery, as reported by the BBC News.
In some countries, e.g. Sweden and Austria, biogas that is already of high quality is already injected directly into the natural gas grid. A book edited by Lens et al. in 2005 presents the fundamentals and full-scale applications of state-of-the-art combination of fuel cell and biomass fermentation technologies for the generation of heat and power.
Let's hope that funding of this kind will continue to be fuelled into projects to produce bioenergy, even in the current climate of cuts in investment.
CABI’s Environmental Impact internet resource has a special section on biofuels research information in the form of abstracts, books, book chapters, reports, reviews, for subscribers, while the CABI Biofuels Information Exchange (http://biofuelexperts.ning.com/) provides free access to over 35,000 research records on biofuels from our CAB Abstracts Database, as well as links to pertinent third party biofuels reports and books, news summaries, discussion forum and more!
Link to press release.
McCarty, P. L.; Bae, JaeHo; Kim, JeongHwan (2011) Domestic wastewater treatment as a net energy producer-can this be achieved? American Chemical Society, Washington, USA, Environmental Science & Technology, 2011, 45, 17, pp 7100-7106, 42 ref.
Lens, P.; Westermann, P.; Haberbauer, M. and Moreno, A.; eds (2005) Biofuels for fuel cells: renewable energy from biomass fermentation. IWA Publishing, UK. xx + 523 pp. ISBN 1843390922.