Background
Welsh Water’s new visitor centre in the Llys y Frȃn Country Park Reservoir, Pembrokeshire, will include a new outdoor activity zone, as well as a waterside cabin, which will support walkers, cyclists and water sports enthusiasts. The centre will also include staff offices and meeting rooms, plus a café, and cycle hire and repair facilities. A total of £4 million is being spent on the project, with £1.7m of EU funding, secured through the Welsh government’s Tourism Attraction Development Programme.
The Overall Objective
The existing Llys Y Fran Wastewater Treatment Works (WwTW) was too small to cope with the expected increase in flow/load following the refurbishment and would not have met future needs, or a more stringent, discharge consent. Civil engineering contractor Young Bros (YB), was responsible for demolishing the works and constructing an enhanced capacity Rotating Biological Contractor (RBC) treatment works in its place. However, it was not possible to do this alongside the existing works, due to the lack of space. YB asked Siltbuster Process Solutions (SPS) to provide a temporary solution to treat the waters generated onsite while the new RBC system was under construction.
Solution
SPS developed a temporary treatment solution in conjunction with Welsh Water (DCWW). Once the contract had been awarded to Young Bros, SPS visited the site with them to determine exactly where the temporary WwTW needed to be located and to finalise the scope of supply. Following an onsite consultation with YB, SPS proposed locating its temporary treatment works on an area of land below the existing works. This meant the old works could be completely demolished and the new upgraded WwTW could be built in the same location. It also eliminated the need for YB to pump wastewater in order to feed it, and instead leveraged the natural gravitational flow.
SPS designed and installed a bespoke small-scale complete WwTW solution that primarily consisted of two HB20 units, tasked with separating suspended solids and associated organic matter from the waste stream, and a MBBR10, which provides the biological treatment stage.
The MBBR10 is our smallest mixed bed bioreactor which uses a duty/standby air blower system to provide the required oxygen, and to keep the media moving and enable the soluble organic matter to be broken down by the fixed film micro-organisms which grow on the media. This biomass is then settled out in the downstream HB20 Lamella settlement tank acting as the secondary settlement tank, with the clear liquid then discharged to the existing final effluent discharge point. The settled sludges from both HB20s were pumped to a local sludge storage tank, with the de-sludge frequency controlled by means of an adjustable timing system on the pump skid.
