When the National Trust’s north western region, based in Grasmere, Cumbria, needed a new commercial package sewage treatment plant to serve the only licensed premises in their property portfolio, Hutchinson Environmental Solutions supplied the most convincing and competitive tender and won the contract to supply, install and maintain.
The Sticklebarn pub, near the head of the Great Langdale valley in the heart of the southern Lake District, and the adjacent public toilets, had previously been served by two aging septic tanks and drainage fields which no longer met the requirements of either the expanding business, visitor numbers or the environment. A 12m long Kee Process NuDisc rotating biological contactor was specified as a replacement system, as was a supply and installation date in the pub’s closed season that pushed both Hutchinson and Kee. Understanding the need not to impact on the vital seasonal trade from nearby campsites and passing fellwalkers for the popular pub, both companies managed already-busy schedules to meet the challenge. Tenders closed in October 2014 and the sewage treatment plant was delivered direct to site at the end of January 2015.
Poor weather at this time of year can affect a major treatment plant installation like this, not only on site where ground conditions can deteriorate very quickly (and reinstatement costs rise in direct proportion) but also in terms of getting large plant, materials and people to “off-mains” locations on icy, sometimes snow-covered, rural roads when daylight hours are short.
Despite being in the most mountainous area in England – the well-known Langdale Pikes sit above the tarn that lends the pub its name – levels between the existing foul drain inlet and the only possible treated effluent discharge point were very tight, to the extent that a treated effluent package pump station had been recommended. Hutchinson put nearly 45 years’ practical experience into revising the layout so that a gravity outlet was possible, saving the National Trust both the cost of the pump station and its ongoing running and maintenance costs. This was also a more “environmentally secure” solution since powers cuts in Langdale are not uncommon: without electricity there is no outlet from a pump station so sewage backs up through the treatment plant – not what you want in such a beautiful and popular tourist location, nor one in which the local tenant farmer breeds and raises internationally-renowned Herdwick lamb and mutton.
Equally sensitive are the surface waters to which the treated effluent is discharged. Great Langdale Beck flows into the phosphate-sensitive SSSI Elterwater Tarn to become the river Brathay, turning south into Windermere Lake just before Ambleside. For this reason, a phosphate dosing system was incorporated into the sewage treatment plant design.
Hutchinson make four planned service and maintenance visits to the sewage treatment plant per year, as well as covering any eventual reactive maintenance as part of the ongoing service agreement.