potential use of hydrogen peroxide in water well rehabilitation

A water supply borehole in the Sherwood Sandstone aquifer in Warrington, UK was found to be infested with iron bacteria that resulted in large ochreous deposits and damaged the pump. Before the pump was replaced, the borehole was treated using hydrogen peroxide. Comparison of the borehole condition seen in CCTV surveys carried out before and after treatment shows that previously observed bacterial growths had been removed. A specific capacity curve was constructed from step test data and used to assess the borehole yield under operational conditions. This showed that the iron bacteria had increased drawdown by some 20% and that the treatment had restored the previous yield characteristics. The improvement is thought to be due to a mechanical scrubbing effect caused by the vigorous release of oxygen bubbles during the decay of the peroxide.