Project Appreciation and Objectives
Greywater recycling (GWR) and rainwater harvesting (RWH) are tools for water conservation, particularly in new developments designed to meet the Code for Sustainable Homes. Depending on the system andthe uses for the GWR or RWH, savings of 6% to 32% of potable water are achievable.
After use, the harvested or recycled water is still discharges to sewer for treatment. With RWH, waste loading is maintained but more wastewater is discharged thank potable water supplied with GWR, although the volume of wastewater discharged is the same as the volume of potable water supplied, the effluent concentration can be higher. Charging schemes therefore need to account for this.
Metering GWR and RWH systems is one option, but technical challenges are substantial; tariff structures are another option. Care is needed to ensure that customers are not deterred from installing useful water conservation measures that may be endorsed by regulators and other parts of the company.
This project will answer the following questions:
- What technical solutions are there for metering RWH and GWR systems? What are the costs and requirements for installation and maintenance?
- If metering is not technically feasible, what alteratnives for wastewater charging could be applied?
Benefits to Clients
- Maintenance of revenue with respect to wastewater treatment as GWR and RWH systems become more prevanlent.
- Technical guidance on metering GWR and RWH systems that will ensure reliable meeting which can be shared with developers and installers.
- Gather experience from the UK and overseas.
- Specification for metering installation, including installation guidelines.
- Economic analysis to develop understanding of how much potable water customers might save, whole life costing of meter installation and investigation of potential alternative charging mechanisms.
- Tariff modelling and impact studies, including Defra's South West Pilot scheme on water affordability, and the UUKWIR study on future methods of charging for the water industry.
- Micro-components of water use, and water efficiency quantification, including leadership of the water using products area of Defra's Market Transformation Programme and Portfolio studies that collected information using WRc's unique Identiflow system.