Bega Cheese Upgrades DAF Plant for Excellent Results

Overview

In Northern Victoria, Sean Trebley, Environmental Manager – Bega Cheese, was presented with the significant challenge of upgrading the ageing wastewater aeration system at Bega’s Strathmerton Plant. The existing system, which had served its purpose for many years, comprised a dissolved air flotation (DAF) unit that discharged into an aerated lagoon. Effluent from this lagoon was then stored in two non-aerated lagoons during the winter months, with irrigation occurring in the summer.

However, as time passed, the surface aerators began to fail progressively. These failures not only compromised the efficiency of the wastewater treatment process but also led to increased operational costs. Repairs were neither simple nor inexpensive. Accessing the aerators required the deployment of cranes or boats, a process that often resulted in damage to the dam liner. The recurring costs and logistical challenges eventually made the continued repair of these surface aerators uneconomical, prompting the need for a more sustainable and efficient solution.

Identifying the Problem

The Strathmerton Plant faced several critical issues. The primary concern was the frequent breakdown of the surface aerators, which had a direct impact on the plant’s ability to maintain optimal levels of dissolved oxygen in the lagoon. This, in turn, affected the overall efficiency of the wastewater treatment process, leading to suboptimal effluent quality and increased chemical oxygen demand (COD) levels.

Furthermore, the maintenance of the existing system had become increasingly burdensome. Each time an aerator failed, the repair process was time-consuming and costly, requiring specialized equipment and expertise. The damage to the dam liner during these repairs posed an additional environmental and financial risk. It became clear that a more robust and cost-effective solution was necessary to ensure the long-term sustainability of the plant’s operations.

The Proposed Solution

To address these challenges, Hydro Innovations was consulted to provide an alternative that would not only replace the failing equipment but also enhance the overall efficiency of the wastewater treatment process. After a thorough assessment, Hydro Innovations recommended the installation of a bank-mounted Gorman-Rupp “EchoStorm” aerator to replace the surface aerators. Additionally, an EDUR DAF pump was proposed to replace the existing pump/compressor/pressure tank system on the DAF plant.

The EchoStorm aerator was selected for its ability to deliver efficient aeration from a bank-mounted position, eliminating the need for equipment to be placed directly in the lagoon. This design choice significantly reduced the risk of future maintenance-related damage to the dam liner and simplified the installation and servicing processes.

The EDUR DAF pump was chosen for its energy efficiency and effectiveness in the dissolved air flotation process. Unlike the old system, which relied on a 7kW recycle pump and a 3-phase air compressor, the new 1kW EDUR PBU 201 DAF pump required significantly less power while delivering superior performance. This upgrade was expected to result in substantial energy savings and a corresponding reduction in operating costs.

Implementation

The project was initiated with the delivery of the new equipment approximately one month after the solution was proposed. Installation was carried out efficiently, with minimal disruption to the plant’s operations. The EchoStorm aerator was installed on the lagoon’s bank, ensuring easy access for future maintenance without the need for costly cranes or boats.

The EDUR DAF pump was integrated into the existing DAF system, replacing the outdated pump/compressor/pressure tank arrangement. The compact size and design of the new pump allowed for a straightforward installation process, further minimizing downtime and disruption.

Performance and Outcomes

Since the installation of the new EchoStorm aerator and DAF pump, the Strathmerton Plant has seen marked improvements in its wastewater treatment process. Shane O’Brien, who oversaw the installation, noted that the improvements in the DAF plant were evident almost immediately. “After just 15 minutes of running the EDUR DAF pump, we could see a significant difference in the DAF tank conditions,” O’Brien commented. This rapid response highlighted the efficiency of the new system and validated the decision to upgrade the plant’s equipment.

Operators have also reported a consistent increase in dissolved oxygen levels within the lagoon, a key indicator of effective aeration. This improvement has had a direct impact on the quality of the effluent, with COD levels dropping by 50% — a significant achievement that underscores the effectiveness of the new system.

The enhanced mixing provided by the EchoStorm aerator has also contributed to the re-suspension of settled solids, making them more bioavailable to colony-forming units. This has further optimized the biological treatment process, leading to a more efficient breakdown of organic matter in the lagoon.

Long-Term Benefits

The benefits of the upgrade extend beyond immediate improvements in performance. The energy savings achieved by replacing the 7kW recycle pump and 3-phase air compressor with the 1kW EDUR DAF pump are expected to result in a substantial reduction in the plant’s operational costs. Additionally, the lower maintenance requirements of the new system will further reduce costs and minimize downtime, ensuring that the plant can operate more efficiently and sustainably in the long term.

Having the aeration system mounted on the bank instead of having to deploy boats or cranes to access equipment, will deliver operational savings well into the future and improve WHS conditions for personnel.

The Result

The upgrade of the wastewater aeration system at Bega’s Strathmerton Plant represents a significant step forward in the plant’s operational efficiency and sustainability. By replacing outdated, high-maintenance equipment with advanced, energy-efficient solutions, the plant has not only improved its wastewater treatment process but also achieved long-term cost savings and reduced environmental impact. This case study serves as a compelling example of how targeted upgrades can yield substantial benefits in industrial wastewater management.

More information about these pumps and aerators may be obtained from Hydro Innovations at Info@HydroInnovations.com.au.