Wastewater Filtration in an Aquifer Thermal Energy Storage (ATES) System

Background

Aquifer thermal energy storage (ATES) is the storage and recovery of thermal energy in the subsurface. ATES is applied to provide heating and cooling to buildings. Storage and recovery of thermal energy is achieved by extraction and injection of groundwater from aquifers using groundwater wells. Systems commonly operate in a seasonal mode. The groundwater that is extracted in summer, is used for cooling by transferring heat from the building to the groundwater by means of a heat exchanger. Subsequently, the heated groundwater is injected back into the aquifer, which creates a storage of heated groundwater. In wintertime, the flow direction is reversed such that the heated groundwater is extracted and can be used for heating, often in combination with a heat pump. (Wikipedia). Amiad’s partner in Denmark, Diatom A/S, was contacted by Suez Water Technology and Solutions, who were working on a project that utilizes municipal wastewater as a heating source for the ground water. The energy from the wastewater is transferred via heat exchangers to the ATES building and reliable filtration was required to protect these exchangers.

Challenge

The main challenge was the fact that the filtration system needed to run on very low pressure, adhering to the concept of using the smallest amount of energy possible.
The maximum operating pressure could not exceed 2 bar, and as the filtration system required higher pressure for backwash, an external backwash pump was installed.

Solution

Amiad recommended disc filtration, as this technology successfully copes with organic contamination, along with an external source design for operating at low pressure.
The 12 x 4” Galaxy disc filters (200 micron) provided the required filtration solution with low energy and water consumption with a small footprint. The scope of supply was for a turn-key system including the filter, pump, instrumentation and control.

Results

Suez is pleased with their decision to install Amiad’s suggested solution and by Diatom’s knowledgeable support before, during, and after installation and on-site service.
Results are excellent and the system is providing:

• Quick ROI
• Reduced energy consumption
• Less wasted resources