The specification process of a rainwater recycling system may be separated into the following two elements:

Transcription

1 The specification process of a rainwater recycling system may be separated into the following two elements: 1) Specification of the rainwater system itself. (i.e. Gravity/Pressurised system, storage tank capacity) System type is dictated by the client and site conditions. Storage tank requirements may be calculated, using projected rainfall and water demand figures. 2) Proposed application for the recycled rainwater. Application of the recycled rainwater is more subjective. The Water Regulations Advisory Scheme (WRAS) Information and Guidance No Reclaimed Water Systems. recommends that a risk assessment is performed for each installation. This procedure would determine if the appropriate controls would be in place for the proposed water use. The following examples have been provided for illustrative purposes, detailing one typical form of a risk assessment carried out in line with the recommendations of WRAS No It should be noted that a risk assessment is site specific, dependant on local conditions and the type of equipment that is utilising the recycled water. The following documents should therefore only be used as guidance when writing individual risk assessments. Rainwater recycling systems are successfully used across the world. It is generally recognised that with basic filtration rainwater is acceptable for nonpotable applications, such as toilet flushing and washing machines. Please note that the information in this document is of an illustrative nature and is supplied by Polypipe Civils Ltd without charge. Although we have endeavoured to ensure the information detailed is accurate, final determination of the suitability of any information or material for the use contemplated and the manner of use is the sole responsibility of the user and the user must assume all risk and liability in connection therewith.

2 Toilet Flushing Water Spray - Droplet skin contact WRAS Information and Guidance (1999) WRAS Guidance (1999) <10,000 per 100ml <10,000 per 100ml Systems sampled by Polypipe Civils have shown levels below the minimum recommendeed levels. UV Disinfection Unit should be considered as a precautionary measure where these criteria cannot be achieved consistently

3 Wash Down Non-food preparation areas Water Spray - Droplet skin contact Partial Body Immersion Accidental Human Consumption The Bathing Water (Classification) Regulations 1991 WRAS Guidance (1999) <10,000 per 100ml <10,000 per 100ml Systems sampled by Polypipe Civils have shown levels below the minimum recommendeed levels. 3. Vortex leaf filter will remove the leaves and 4. The inline filter will remove small particles UV Disinfection Unit should be considered as a precautionary measure where these criteria cannot be achieved consistently Warning Notices Draw-off points marked and identified in accordance with WRAS Information and Guidance No

4 Cistern Hand Basins Hand Immersion Accidental Human Consumption The Bathing Water (Classification) Regulations 1991 The Bathing Water (Classification) Regulations contained in initial 2. UV Disinfection Unit Warning Notices Draw-off points marked and identified in accordance with WRAS Information and Guidance No

5 Bathroom & Washroom Hand Basins Partial Body Immersion Accidental Human Consumption The Bathing Water (Classification) Regulations Vortex leaf filter will remove the leaves and 4. The inline filter will remove small particles 3. contained in initial 4. UV Disinfection Unit Warning Notices Draw-off points marked and identified in accordance with WRAS Information and Guidance No

6 Jet Wash Water Spray - Droplet skin contact The Bathing Water (Classification) Regulations 1991 The Bathing Water (Classification) Regulations contained in initial 2. UV Disinfection Unit should be considered as a precautionary measure where these criteria cannot be achieved consistently. Continued

7 Jet Wash ( Continued) Aerosol - Inhalation UK Water Supply 1. contained in initial 2. UV Disinfection Unit requires a specific risk assessment following recognised code of practice.

8 Garden Irrigation Partial Body Immersion Accidental Human Consumption WRAS Information and Guidance (1999) WRAS Guidance (1999) <10,000 per 100ml <10,000 per 100ml Systems sampled by Polypipe Civils have shown levels below the minimum recommendeed levels. 1. contained in initial 2. UV Disinfection Unit should be considered as a precautionary measure where these criteria cannot be achieved consistently Warning Notices Draw-off points marked and identified in accordance with WRAS Information and Guidance No

9 Washing Machine Dry Residue Skin Contact WRAS Guidance (1999) No grit, low suspended solids. WRAS Guidance (1999) <10,000 per 100ml <10,000 per 100ml Systems sampled by Polypipe Civils have shown levels below the minimum recommendeed levels Washing machine manufacture should be consulted to ensure no guarantee is invalidated 1. contained in initial 2. UV Disinfection Unit should be considered as a precautionary measure where these criteria cannot be achieved consistently

10 Shower / Bathing Full Body Immersion Accidental Human Consumption UK Water Supply Regulations contained in initial 2. UV Disinfection Unit should be considered as a precautionary measure where these criteria cannot be achieved consistently 1. UV Disinfection Unit. 2. An appropriate water quality testing/monitoring program

11 Swimming Pool Full Body Immersion Swimming Pool Water Treatment and Quality Standards, 1999 water. ( colour, odour). Recommended turbidity < 0.5 NTU Swimming Pool Water Treatment and Quality Standards, 1999 No bacterial counts per 100ml for total coliforms. Counts < 10 per 100ml are acceptable provided not in consecutive samples. No E.coli per 100ml Additional control may be necessary. An appropriate water quality testing/monitoring program is recommended 1. contained in initial 2. UV Disinfection. Additional controls may be necessary. An appropriate water quality testing/monitoring program is recommended. Continued

12 Swimming Pool ( Continued) Accidental Human Consumption 1. contained in initial 2. UV Disinfection. Additional controls may be necessary. An appropriate water quality testing/monitoring program is recommended