Many contaminated sites redeveloped in the 1970s and 1980s are being reassessed by regulators – and found wanting. In some cases further remediation is necessary. This is the situation facing St Michael’s golf course in Widnes, Cheshire.
Back in the mid-1970s, Halton borough council in Cheshire decided that something had to be done about a 55 hectare (ha) chemical waste tip known locally as Ditton Alps. Initially, half the site was reclaimed and transformed into a nine-hole golf course, which opened in 1977. About a decade later the remainder of the site was remediated and another nine holes unveiled. But fast forward to the present day and the council is once again planning remediation of the site.
The problem lies with the area redeveloped in the 1970s. Work undertaken in those early days just wasn’t good enough, Halton’s Mike Curtis told CLM. A drainage system wasn’t properly installed and contaminated material wasn’t properly capped. Instead, just a couple of inches of top soil was spread over the area. This means that rain is able to reach contaminants, producing leachate that pollutes a brook running through the site. The less-than-adequate capping also raises potential human health risk, with arsenic concentrations identified as a particular concern.
It is worrying that a site once deemed to have been cleaned up is now in the process of gaining PartIIA special site status, but there is a bright side to the story. The second stage of remediation was much more effective. The section cleaned up in the late 1980s isn’t a source of significant pollution or risk – an example of how the quality of remediation has taken huge strides forward.
Remediation contractor Land & Water is leading the team charged with putting right what 1970s reclamation got wrong. High on the agenda is construction of a permeable reactive barrier (PRB) to treat leachate, Land & Water’s Simon Bamford told CLM. Designed in conjunction with Queen’s University Belfast and Jacobs Babtie, the PRB offers two crucial advantages: it will be underground and therefore inaccessible to vandals; and running and maintenance costs will be very low. Because Halton plans to make use of Defra’s capital projects funding scheme to pay for remediation, the council is keen to minimise on-going operating and maintenance costs – Defra’s scheme is only designed to stump up for capital expenditure. |
