Viterra’s Tamworth malt facility has a grain capacity of 45 kt and supplies malt both domestically and internationally. The plant required an advanced water treatment plant (AWTP) to treat malting steep water to a quality suitable for re-use within the facility.
Ovivo Australia designed and constructed a cutting-edge AWTP using membrane bioreactor (MBR) and reverse osmosis (RO) technology.
The MBR and RO perform all the necessary steps to treat the influent to a condition suitable for re-use within the client’s facility and to maintain discharge agreement conformance for the reject stream generated.
The malting steep waste is initially screened, balanced, pH corrected and biologically treated to reduce BOD/COD, nitrogen and phosphorous. Permeate is drawn through two immersed membrane trains reducing TSS levels and pathogens. The MBR permeate is further treated through a dual-stage RO system to remove dissolved content and pH corrected before being stored for re-use. The process designed by Ovivo incorporates the use of a bioselector that conditions the wastewater prior to biotreatment and enhances biological phosphorous removal.
The AWTP, which is capable of treating a hydraulic load of 300 kL per day, can recover 75% of the wastewater which equates to approximately a 50% reduction in Viterra’s reliance on local potable water supply.
Ovivo was able to provide the client with capital cost savings over conventional activated sludge systems. The AWTP performed the same function but with a reduced footprint and associated civil installation costs. The technology used resulted in a compact and efficient means of improving water quality and is well suited for re-use applications. The AWTP, which was delivered as design, build and operation (DBO), enables water savings of 50 ML per year.
Since commissioning, plant reliability has been stable with minimal requirement for process adjustments. The aeration system uses Ovivo’s Aerostrip Fine Bubble Diffusers, a high-performing membrane diffuser that has provided high SOTR against power input. The efficiency has been shown as 4 – 4.2 kg O2/h/kW input. Optimisation of the positive displacement blowers is achieved through Ovivo’s DO control strategy.
The plant is controlled via a SCADA system that allows for remote monitoring and trending.
This type of advanced water plant is the fifth of its kind that Ovivo has completed for the Australian food and beverage sector. The experience has shown that production of potable-grade water for non-potable re-use from industrial trade waste is a reality, with proven long-term operational stability and reliability.