The installation of a range of pumps and related equipment as part of an international beer brewer’s expansion in Gauteng has helped ensure water and energy efficiency.

The range of Grundfos submersible pumps, smart digital pumps and vertical multistage centrifugal pumps were installed at the Sedibeng brewery’s wastewater plant and water treatment plant. The installation included the installation of a water recovery plant, allowing the operation to further optimise water use within its facility.

The expansion also saw the upgrading of the water treatment plant, where clean ‘raw’ water from the municipality is further purified for brewing purposes. After the beer is produced, beer residues and water used for pipe cleaning is treated to meet regulated environmental discharge limits. The water can also be re-used for cleaning, further saving water.

According to Grundfos associate sales engineer Raymond Makgoga, three submersible wastewater pumps were provided to transfer water from the brewery to the water recovery plant. After the sedimentation process, water is pumped to the reclamation plant for final treatment. In this circuit, about 6 000 m³ of water is pumped daily, with the pumps being driven by 15 kW high-efficiency motors with IE3 rating.

“In the water treatment plant, a number of Grundfos Smart Digital S and Smart Digital XL pumps are installed, mounted on dosing skids,” says Makgoga. “These must accommodate a range of chemicals from sodium hydroxide and sodium hypochlorite in the reverse osmosis circuit, to citric acid and anti-scalant in the ultra-filtration circuit.”

“These systems give a high level of control, communicating vital data between the pump and the programmable logic controller (PLC) so that chemical dosing is accurate and appropriate,” he says. “This eliminates over-dosing and ensures that chemicals are not wasted; the Grundfos pumps are able to measure the volumes of water flow and then dose in proportion.”

The dosing pumps include Grundfos’s CIU 500 interface, which is a standard interface for data transmission between an industrial ethernet network and a Grundfos pump or controller, making data exchange possible between the pumping systems and a PLC or supervisory control and data acquisition system. Other accessories in the package include pressure relief valves, pressure loading valves for maintaining pressure on the discharge line, and pulsation dampeners to ensure smooth dosing flow.

Energy efficiency was also an important factor for the Sedibeng facility, considering the significant energy consumed by wastewater treatment plants, with large pumps transferring about 1 750 m³ of water an hour, pumping 24 hours a day. To monitor and conserve energy, the company uses a Utilities Benchmark Model which compares the electricity used with the kilograms of water treated and chemical oxygen demand (COD).

The use of IE3 energy efficient motors in the Grundfos pump installations assisted in reducing energy consumption to about 1.3 kW per kilogram COD treated, from a previous level of over 1.9 kW. The new equipment helps to facilitate daily data tracking, helping the operation work towards even more demanding energy saving targets.

Grundfos service sales agent Nancy Khumalo explains that energy savings can be modelled in advance to indicate how the company’s pump installations can improve energy consumption.

“This allows our customers to consider how the Grundfos pumps could contribute to reducing their carbon footprint and their actual electricity costs,” says Khumalo. “We are also able to provide an estimation of the capital payback period based on these savings.”