One of our recent jobs saw us called to a site in County Durham with 2 existing boreholes and a spring water supply. The boreholes had run into various problems and were plagued by water quality issues.
We were asked to identify the issue and after undertaking water analysis, the results showed the supply had failed on E.coli, sulphate and iron + manganese. This needing resolving as part of the private water supply regulations. However treatment wasn’t straight forward and left the land owner with the following options:
- Treat by Reverse Osmosis – prohibitively expensive, time intensive and would reduce the flow rate significantly.
- Drill a new shallower or deeper borehole to see if water quality improves and produces enough volume.
After discussing the options we were asked by the owners to undertake a hydrogeology report and investigate whether a new borehole could be drilled (either by drilling deeper or shallower) that provided sufficient volume and better quality water.
Post hydrogeological investigation we discovered that a new, shallower, borehole would provide better quality water but not in the volume and flow rate required. This required a further step and our proposal was to blend water from the new borehole with one of the existing boreholes, pipe them to a WRAS approved water storage tank and then boost them to the point of use.
Blending Private Water Supplies
Blending a water supply requires access to two water supplies (sometimes not feasible) where the supply with elevated level of the offending substance(s), is blended with another supply to dilute the water. This can be done in various ratios under controlled conditions to get the desired results. The system can then be set at the ratio of the two supplies and the system monitored and analysed long term to ensure that the correct, and desired, water quality is maintained.
Advantages of Blending Private Water Supplies
- Very good for problems that are difficult to treat via conventional methods
- Private supplies can be blended with mains supplies providing they are done so in a compliant manner with an appropriate type of control and air gap system in a storage tank.
Disadvantages of Blending Private Water Supplies
- Requires two water supplies – sometimes this is not feasible.
- Costs are incurred to blend the supplies correctly and also to monitor that the blended supplies maintain a consistent water quality.
If you are interested in potentially blending supplies contact us to discuss how this can be done.