Aerobic biological treatment of abattoir wastewater has been a commonly used practice for many years. The treatment system is designed to reduce BOD by up to 95% by introducing dissolved oxygen into the wastewater to help with the decomposition of organic substances. But there are many and varied aeration systems to chose from. There are [among others] Splasher or propeller type aerators that sit on the surface of lagoons, submersible aerators that are below the surface, and Venturi-Aerators which are mounted on the banks of lagoons.
Venturi-Aerators, distributed in Australia by Hydro Innovations, use a bank mounted self-priming pump to draw water from the lagoon, then discharge it at pressure, accelerating it into the nozzle of the venturi-aerator. This acceleration [from 3.6m/s up to in excess of 16.5m/s] creates a vacuum that draws in 2.2 times more air than fluid pumped, and mixes air with water. A hydraulic shear facilitates the release of soluble gases and volatiles from the water and it is discharged, saturated with dissolved oxygen.
According to Hydro Innovations, the venturi-aeration [V-A] system can deliver high oxygen transfer efficiencies, but the biggest advantage to the system is the ease of access for monitoring, servicing and maintenance. Because the system is located on the banks of lagoons, not floating on them, operators can safely and easily access them. This has a very positive impact not only on safety, but on maintenance costs.
With the V-A system, no cranes or boats are necessary to access equipment, eliminating the associated risks [and costs] of having to use them. Downtime is also greatly reduced because of the speed at which the equipment can be accessed, and because Gorman-Rupp pumps are used to provide the flow and pressure, any service required on the pump is able to be done in a very timely manner.
Asset owners can also derive a level of peace of mind with the system, as pumps and venturi-aeration units are designed, cast, machined, assembled and tested in the USA. More information about this system can be obtained from info@HydroInnovations.com.au
Image shown at top is A “bank-mounted” Gorman-Rupp pump and Venturi-Aerator system
