Stonehenge Water Management - AWARD

Tender description

Stonehenge is a prehistoric monument located in Wiltshire, approximately 2 miles west of Amesbury and 8 miles north of Salisbury. One of the most famous sites in the world, Stonehenge is the remains of a ring of standing stones set within earthworks. It is in the middle of the most dense complex of Neolithic and Bronze Age monuments in England, including several hundred burial mounds. The site and its surroundings were added to the UNESCO's list of World Heritage Sites in 1986 in a co-listing with Avebury Henge. It is a national legally protected Scheduled Ancient Monument owned by the Crown and managed by English Heritage. Surrounding land is owned by the National Trust. A new visitors centre, located at Airman's Corner approximately 1.3 miles from the stones, opened in December 2013. The centre houses permanent and temporary exhibitions, as well as a gallery, a gift shop, café, office space and toilet facilities. Also located on site is an ancillary building with site offices and essential services equipment. Given the distance between the coach drop off zone and the visitor centre toilet facilities, a new toilet block was built and commissioned in 2017. Under the provisions of an Environment Agency abstraction consent, the potable water supply (PWS) on site is provided by a private borehole. It is subsequently treated for nitrogen and pathogen removal prior to storage and distribution. A second borehole provides the heating and cooling energy required for the ground source heating and cooling system (GSHC). This is an open loop system with the abstracted water being returned to a third borehole. In an effort to reduce the volume of water abstracted for use on site, a n activated sludge membrane bioreactor (MBR) wastewater treatment plant is designed to treat wastewater to an extremely high standard in order that it may be re-used in the two toilet blocks for toilet flushing. As a secondary means of discharge, treated effluent may also be dispersed to a soakaway for infiltration to groundwater. Vacuum drainage systems (VDS) installed at both toilet blocks reduce the volume of water required for each flush. Whilst all of these systems are independent systems, they all work together to achieve the provision, distribution and treatment of water on site. Historically, these systems have been managed and operated independently without cross-communication between O&M providers, which has not allowed for the optimisation of their operation or the efficiencies afforded by bringing the management of these systems under a single point of operation responsibility. As a part of three year cycle, English Heritage are re-visiting the operation and maintenance contracts that manage the potable water, ground source heating/cooling, vacuum drainage and the wastewater treatment plant. Given the critical importance of delivering safe drinking water, protection of the environment and the challenges of complian...