Bega upgrades wastewater aeration system

Sean Trebley, Environmental Manager for Northern Victoria, was given the task of upgrading the wastewater aeration system at Bega’s Strathmerton plant. The existing system consisted of a dissolved air floatation (DAF) unit, which flowed into an aerated lagoon. The resulting effluent was stored in two non-aerated lagoons during winter, with irrigation occurring in summer.

Over several years, the aging surface aerators had progressively failed, with repairs requiring the deployment of cranes and boats to gain access. This process was expensive and resulted in damage to the dam liner. Eventually, it became uneconomical to keep repairing the aerators.

Hydro Innovations recommended the installation of a bank-mounted Gorman-Rupp EchoStorm aerator for the lagoon to replace the surface aerators and an EDUR DAF pump to replace the existing pump/compressor/pressure tank system.

The 1 kW EDUR PBU 201 DAF pump eliminates the need for the 7 kW recycled pump and the three-phase air compressor, helping save energy costs. The pump has allowed the water to be aerated more efficiently and effectively before being transferred to the lagoon.

Operators have observed a continued increase in the dissolved oxygen level in the lagoon and have seen COD fall by 50% since installation. Due to the higher level of mixing, re-suspending settled solids became more bioavailable to colony-forming units.

Operators in Germany and the USA have been benefiting from similar upgrades for decades, retrofitting EDUR DAF pumps to older DAF systems to improve their efficiency and reduce maintenance costs. Systems from 1 to 22 kW are available with a range of materials including cast iron, stainless steel and super duplex.