Case Study

Successful Temporary Water Management Solution at Sewage Treatment Works

Infrastructure

Sewage Treatment Works at Witney, Oxfordshire needed to increase Flow to Full Treatment by March 2025.

Part of this extensive project included building new Final Settlement Tanks (FSTs) and Primary Settlement Tanks (PSTs) at the facility, the construction of which was led by Tilbury Douglas. Significant excavation was required in order to construct the below-ground tanks.

Challenge

Due to the size and depth of the excavation, large amounts of groundwater and surface water runoff entered the area during works. Clay contaminants in the ground and geographical strata meant that, once water entered the area, it became contaminated with high levels of particulate that required treatment.

RVT worked closely with Tilbury Douglas to ensure all elements of water treatment and discharge were suitable, dependable, and regulatory-compliant whilst navigating the complexities that the project presented.

Solution

RVT proposed a tailored solution including an EnviroHub® TT10 Treatment Tank paired with an EnviroHub® TU02 Chemical Dosing System to pH neutralise the contaminated water. At this point, flocculant was added on a meticulously calculated, flow-proportional basis before being pumped into the EnviroHub® HL50 Lamella Plate Settlement Tank where suspended solids were separated from the water.

This strategy treated contaminated water from the excavation works whilst adhering to the following strict discharge requirements to avoid harming biomass and potentially disrupting the sewage plant's treatment capabilities.