A chicken process plant in South Australia needed aeration to reduce odours at their wastewater treatment system. The plant had a large 350,000 litre tank, with in-flows exceeding 4 megalitres per day. They also wanted a system that was easy to maintain and safe for operators.
Engineers at the plant selected a Venturi-Aeration system. It consisted of two VA-1100 [6”] Venturi-Aerators, “powered” by two Gorman-Rupp pump model V6A60-B. The combined discharge rate is 140 litres per second [L/s]. The Gorman-Rupp pumps draw the wastewater from the tank and discharge it at pressure into the Venturi-Aerators. Air is drawn into the aerator at a ratio 2.2 times the pump flow, where it is mixed with the wastewater. Water is then discharged back into the tank, where “hydraulic sheer” facilitates the release of soluble gasses and volatiles from the water. The water is now saturated with dissolved oxygen.
The discharge of the two aerators were set up tangential to the side wall to induce a “spin” to the contents of the tank. This causes solids to migrate to the centre, where the pump suction lines were positioned. This way, large solids are collected, smashed through the pump and aerator, reducing their size and making them more available for biological reaction.
Hydro Innovations Regional Manager, Shaun Allgood recently visited the plant. Shaun noted that everything had been installed perfectly and was operating very well. A spokesperson from the plant said they were very happy with the system and its odour reducing capabilities.
The plant has found the system very easy to access for monitoring and maintenance. Because it is located outside of the tank [not in it or on it], there is need no lifting apparatus to access equipment. There is no “working over water” or “working at heights” to contend with or write up on risk assessment documents.
Smaller projects are possible with the use of smaller Venturi-Aerators, which are available in 50mm, 80mm, 100mm and 150mm sizes. Larger projects are approached by using multiples of the larger unit, sometimes using a dedicated large pump to “drive” two, three or even four Venturi-Aerators.