The Challenge
Redesigning a Potable Water Treatment Facility to Remove Contaminants While Saving Energy
A potable water treatment facility located along Lake Biel in western Switzerland was completely redesigned to supply clean, safe drinking water to 70,000 residents in Biel and Nidau. Driven by the need for energy efficiency and resilience against climate change, utility provider Energie Service Biel/Bienne (ESB) aimed to cut energy use and trace contaminants, ensuring reliable water treatment despite fluctuating raw water quality.
Location
Biel, Switzerland
End User
Energie Service Biel/Bienne (ESB)
Est. Cost Savings
$120,000 /year*
OEM
Membratec S.A.
Est. Energy Savings
400 MWh/year
Est. CO2 Emissions Savings
269 MTCO2e /year
The Solution
Low-Pressure PX® Pressure Exchanger® for Reduced Energy Consumption
ESB collaborated with Membratec S.A. to replace the existing plant with a reverse osmosis (RO) water treatment facility to ensure an energy-efficient provision of high-purity water. The plant features a modern membrane system to remove contaminants, especially chlorothalonil products. Aiming to minimize the use of chemicals for higher water quality, the designers chose to eliminate the use of antiscalants.
However, removing these chemicals results in a lowered permeate yield from the RO system. Consequently, higher pressure and more energy are required to meet the desired permeate output. To save energy and associated costs, the designers implemented an energy recovery system using the Low-Pressure PX® Pressure Exchanger® (LP PX) from Energy Recovery.
The plant’s final capacity with first phase and second phase will be 1,200 m3/h with an RO system of 600 m3/h resulting in production capacity of 14,400 m3/day of RO permeate, which will be blended with bypassed ultrafiltrated water. The RO is integrated in a complete treatment system (ultrafiltration, reverse osmosis for half of the flow, ozonation, GAC filtration). The first phase of RO includes two PX LP180 units into each train and the fully commissioned plant will have 16 low-pressure PXs installed.
Award-Winning Water Treatment Design
With the contribution of the PX Pressure Exchanger technology, the energy consumption of reverse osmosis permeate falls below 0.6 kWh/m3 to ensure energy efficiency for cost-effective clean water production.
Each pressure exchanger transfers hydraulic power, allowing the system to reduce the energy consumption of reverse osmosis and the size of the high-pressure pump.
Membratec S.A.
The Result
- Once fully commissioned, the potable water treatment facility will save an estimated 400 MWh/year, roughly equivalent to 30% of the energy consumption of the new system, and save an estimated $120,000 USD in operating costs annually.*
- Integration of the LP PX is essential for saving energy, reducing operational costs, and reduces the specific energy consumption of the permeate to below 0.6 kWh/m3.*
- The plant’s new energy-efficient design integrates the PX with innovative features to reduce electricity consumption and support Switzerland’s net-zero goals.
*Actual results may vary. Energy cost savings are calculated based on 8 lines in operation, with the cost of electricity being $0.32/kWh.