Technologies

Technological solutions to reduce the climate change impacts of water and wastewater infrastructure vary widely. They can include:

• Energy-efficient pumps and distribution and collection systems.
• Energy-efficient wastewater treatment systems.
• Composting and other climate-friendly systems for managing wastewater biosolids and sludge.
• Energy production from biosolids biogas digestion.
• Electrical power generation, through micro-hydro additions to from water supply systems micro-hydro.
• Heating and cooling from wastewater sewer heat recovery.

For example, Woking Borough, in the United Kingdom, supplies combined heat and power and renewable energy. It also implements energy and environmental services in both the public and the  private sectors. The key to its s success is the combination of four factors:

• Technical innovation (such as the combined heat and power system, absorption cooling, etc.)
• Partnerships with the private sector.
• Financial and commercial innovation.
• Use of a local electricity balancing and trading system.

Issues to Consider

• Tradeoffs. There are often tradeoffs between performance of water and wastewater treatment systems, land requirements, and energy consumption/greenhouse gas emissions. For example, treatment systems that use membrane filtration technology result in very high performance and need little land, but they often entail higher energy consumption.
• Centralized vs. decentralized treatment. Centralized systems are often more cost effective due to economy of scale. This allows them to take advantage of high-performance technology that allows even better efficiency. However, these advantages must be balanced against the costs and impacts of piping the wastewater over a longer distance and the relative difficulty of making good use of the larger quantity of recycled water that results.