The situation
A pumping station feeding water to a treatment scheme was failing too often, becoming costly and time-consuming to fix. The customer approached Oren Environmental to find a long-term, more cost-effective solution to the problem.
They also wanted to eliminate any risk of polluting the nearby river with untreated water. The water contained harmful deposits, so sending it to a treatment plant was essential to avoid negatively impacting the river’s ecosystem. Additionally, the deposits were damaging the pumps when they were left to sit redundantly in the untreated water when the pumping station failed.
Our approach
Upon investigation, we discovered that the pumping station was initially built using a Direct-on-Line (DOL) system that runs pumps at full speed. This system relies on a lot of electrical energy to pump the water and leads to many starts and stops, which reduces the lifespan of the pumps.
We also found that the non-return valves (NRV), which prevent water from returning to the tank after being pumped away, were located at the bottom of the chamber, making them very difficult to access. Additionally, there were no isolation valves that could be closed manually in the event of an NRV failure, posing the risk of the water returning to the wet well and filling it up again.

Our approach was to refurbish the pumping station and design and build a new solution that would have lower whole-life costs, be safer to access and be more energy-efficient and sustainable to run.
We did this in two parts. Firstly, we redesigned the pipework within the chamber to make it more accessible to operators, negating the need for them to be lowered into the chamber via a harness in a deep and confined space. This also included installing gear isolation valves that could be isolated from the surface.
Secondly, we converted the old DOL system to a variable-speed drive (VSD) system, which has several benefits. It allows us to programme the pumps to automatically maintain the water levels to preset requirements, rotate them so they have even wear, and ensure they stop and start slowly to prevent pump damage.
Obstacles we overcame
- Maintaining operations –
The pumping station had to remain operational while we refurbished it. Otherwise, the untreated water would overflow and potentially pollute the environment.
To manage this, we installed an external power supply outside the kiosk that houses the control panel for the pumping station. Then, to enable us to enter the chamber to replace the pipework, we used those external power supplies to put temporary pumps into a chamber further up the pipeline. We also installed an over-pumping solution to keep the water moving as we worked. - Gaining access–
The pumping station is located in the yard of a local tool hire company. To overcome this, we built a good relationship with the onsite contacts and kept them as informed as possible to minimise disruption to their site.

Our impact
As a result of our work:
- Water levels are now consistently controlled and maintained
- The pumps no longer fail and will last for longer without frequent need for repair
- The tool hire company is less inconvenienced by our accessing their site to fix pump problems
- Less energy is used to keep the pumping station operational and, therefore, fewer costs
- Any risk of untreated water polluting nearby watercourses is reduced

