Soma Services has been proud to include the National Trust on its client data base since being invited to investigate problems with the sewage treatment plant at Fountains Abbey West Gate in 2006. After carrying out three contracts on the Fountains Abbey & Studley Royal Estate Soma has recently been awarded a contract for supply and installation of a new sewage treatment plant and associated drainage works at Nostell Priory to a total value of £368,000.

In the 1980’s a Clearwater Biospiral treatment system had been installed on land adjacent to the Fountains Abbey West gate to treat foul flow from toilets and the Visitor Centre restaurant. This system was well maintained by a local contractor and as a result had given good service. However, with increasing visitor numbers and plans for increased promotion of the restaurant facilities, Soma Services were engaged to monitor the performance of the plant and to recommend a cost effective upgrade to ensure future compliance with the requirements of the Environment Agency. The consented discharge standard only included numerical reference to BOD5 and suspended solids but with future flows in mind and the likelihood of tightening of standards imposed by the Environment Agency consideration needed to be given to removal of ammonia.

The August Bank holiday period was selected to monitor visitor numbers and performance of the plant in detail and a sampling strategy was devised to enable the point, in terms of visitor numbers, at which the Biospiral plant failed to meet the required standards to be identified. The resulting data was processed and the options for upgrade works were presented in a formal report.

Tender documents were issued to a number of suppliers and after due consideration the contract to supply and install the new system was awarded to Soma Services as the lowest bidder and also the only company offering a solution that utilised the existing equipment. The existing Biospiral plant, although old, was still in very good mechanical order and using this equipment as part of the new scheme offered substantial savings. A WPL High Performace Aerated Filter (HiPAF) biozone/humus module was selected to operate in series with the Biospiral unit. Ongoing sampling of the system since the installation has shown that, at current visitor levels, the upgraded works provides full nitrification as well as compliance with the consented standards and it has been calculated that the system could now deal with a significant increase in visitor numbers without further modification.

Following the successful completion of the West Gate project a similar exercise was carried out at the Studley Royal Canal gates location. Here a toilet block was served by an old septic tank and filter bed discharging to a soakaway which had not operated correctly for some time. Smell nuisance had been reported and a long term solution was required. The nearby tea rooms were served by a septic tank which also gave rise to some degree of smell nuisance.

The solution proposed was the installation of a package treatment plant serving both locations with a discharge to the lake consented by the Environment Agency. Theoretical calculations of foul flows to treatment from visitor numbers were compared with water meter readings, a basis for design was agreed and a WPL HiPAF was selected for installation in a wooded area behind the tea rooms.

The contract executed by Soma Services included application for a Consent to Discharge, supply and installation of the treatment plant as well as foul and discharge drainage to make the necessary connections from the toilet block, tearooms and point of discharge consented by the Environment Agency. The route of the drainage included two road crossing and grassed areas in view of the public and a high standard of reinstatement was essential. This was achieved with minimum inconvenience to the public throughout the project.

Also within the Fountains Abbey Estate is the How Hill Holiday Cottages development where the local planning authority required particular attention to foul drainage of the site. A solution was provided by Soma Services following negotiations with English Nature addressing issues of a great crested newt population. In accordance with Consent to Discharge obtained from the Environment Agency a WPL HiPAF package sewage treatment plant was installed and a soakaway system carefully designed and constructed to follow the contours of the site. In this way a highly treated effluent is dispersed into the ground eliminating the risk of adverse environmental impact on the site, the adjoining land and water feature.

The Nostell Priory near Wakefield was served by a very old stone filter bed system which due to growth of visitor numbers did not provide sufficient capacity and was beyond economic repair or refurbishment. The site drainage and alternative treatment options were fully investigated by DSSR Consulting Engineers and a WPL HiPAF treatment system was selected. A contract to supply and install the new treatment plant together with extensive drainage works to deliver foul flows from the Priory buildings to the new treatment plant location has been awarded to Soma Services. The works are currently in progress and Soma staff are working closely with the on site archaeologists, the local building control department and the local planning department regarding tree protection.

More information about Nostell Priory can be found at the following websites:
National Trust page for Nostell Priory
Nostell Priory Holiday Park

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