The 0.9 acre former gasworks at Fareham in Hampshire lies on the banks of the Fareham Lake, an inland finger of Portsmouth Harbour. The works in Bath Lane were established by the Fareham Gas & Coke Company in 1856, but gas production ceased in 1925 when the Gosport Gas & Coke Company took over the supply of gas to the holder station. Natural gas reached the area in 1970/71 when the Fareham equipment was modernised. The gasholders were finally demolished in 1993.
In 1996, following discussions with the Environment Agency, English Nature and other bodies, a remediation scheme was devised to clean-up the former gasworks and the adjacent foreshore. Restricted access to the site meant that lorry movements had to be minimised, and as much of the material as possible had to be treated on-site. The evolving technique of bio-remediation was employed to enable natural soil bacteria to break down the contaminants. Early in 1997, before work could start on excavating the foreshore, a coffer dam was installed to protect the workings. This was constructed from sheet piling driven into the bed of the Fareham Lake. Extreme care had to be taken during piling operations because of the proximity of nearby waterfront houses. Once the contaminated material had been removed, the voids were backfilled with imported stone. On completion of the excavations the coffer dam was removed.
Two bio-remediation beds were constructed in the base of an old gasholder. Slotted PVC drainage pipes were installed to collect water as it percolated through the cells. A layer of lightly contaminated soil was added, on top of which were laid 40mm slotted pipes to provide aeration of the soil from a remote, electrically driven blower. Suitable contaminated soil excavated from the foreshore was mixed with a nutrient and loaded into the beds. Once the beds had been filled, irrigation pipes were laid on the surface and a polyethylene cover provided. The material contained within the beds was turned over monthly using a mini-excavator. After six months the natural bacteria had converted the contaminants to carbon dioxide and water, allowing the re-use of the cleaned material at a later stage in the site remediation.
Fareham Lake is a Site of Special Scientific Interest (SSSI) and is an attractive location much sought after for waterside properties. It is envisaged that the land will be sold to a residential developer.
