Bespoke EnviroHub Water Treatment System Protects Environment and Local Community During Construction of Housing Development
Project Overview
Bellway, one of the UK's largest house builders, was undertaking construction work on a new housing development which consisted of 370 new homes. Of these homes, 222 will be for private sale, while the remaining 148 will be available through shared ownership schemes.
Challenge
After the completion of earthworks, Bellway constructed an attenuation pond at the lowest point of the site. However, an unrecorded water main was discovered within a nearby carriageway. This unexpected discovery obstructed the original route planned for the new outfall pipe.
During this time, the area experienced heavy rainfall and melting snow, causing the ground to become saturated. Water began to collect in the attenuation basin, with no outfall available to discharge it. The attenuation pond had around 600mm of freeboard remaining and contained significant volumes of silt-contaminated water. If it continued to rain, there was a risk of the pond overtopping, leading to an uncontrolled discharge that would negatively impact the nearby carriageway and cause a pollution incident in the nearby brook. Bellway were keen to prioritise finding a way to reduce the water level in the pond, whilst the new outfall was being created. Otherwise, the impact on the environment and local community could have been severe.
Bellway took immediate action and reached out to RVT for support.
Solution
RVT collected water samples from the site and performed in-house jar tests.
The results showed that the water had a high concentration of colloidal (clay) matter and low alkalinity levels, which is a challenging situation. Adding metallic salt to neutralise the coagulants would decrease the alkalinity and pH levels further. Considering these factors, we swiftly modified our systems and adjusted our conventional chemical dosing method from using a metallic salt and anionic polymer to using a metallic salt and caustic soda. This change helped us maintain suitable pH levels while still achieving adequate flocculation. As a result, we were able to decrease the turbidity readings from 4000Ntu down to 5-10Ntu, which was a significant improvement.
RVT proposed a full chemical dosing system with caustic dosing for pH correction, along with real time data monitoring and alarms to ensure treatment efficacy 24/7.
The system reduced the TSS, Turbidity and maintained pH level within the Environmental Quality Standards.
Bespoke Water Treatment Solution for Bellway
RVT Group supplied a system capable of treating 14 litres/second consisting of:
- EnviroHub TU02 Dosing Skid to automatically add the dose required to achieve adequate water quality.
- EnviroHub TT10 Treatment Tank for PAC and Caustic dosing.
- EnviroHub HL50 Lamella Plate Settlement Tank for solids separation.
- EnviroHub TT03 Treatment Tank – 3m3 Holding Tank, to allow the effluent from the lamella to be pumped to the outfall.
RVT also provided
- An EnviroHub Monitoring Unit to monitor the pH, turbidity and flow of water.
- Soundex® Curtains to ensure that any noise created by the EnviroHub solutions was kept to a minimum.
Contact us to discuss your site water solutions
This case study was produced and originally issued by RVT Group - construction industry partners for EnviroHub. To contact them directly, please call 0808 178 3286 (7:30am to 4:30pm Mon-Fri).
To discuss EnviroHub solutions for your quarry, please contact brand owners Atlantic Pumps on 0800 118 2500 or complete our enquiry form.
Gallery
RVT's In-house jar test
Sample before treatment (left), Mid-treatment (centre), After treatment (right)
Treatment Tanks are designed to pretreat water with coagulant and flocculent polymer to improve settlement of solids, or for pH correction.
The HL50 is RVT's largest settlement tank, designed to remove suspended solid particles from water (50m² volume).
RVT's acoustic curtains are certified to reduce noise by up to 32.9dB and achieve up to 98% noise absorption.
