DAF Float Processing and Hydrocyclone Trial

Summary

​Wastewater streams from red meat processing (RMP) plants can contain high levels of fats, suspended solids, biological oxygen demand (BOD) and other elements that are unacceptably high for industrial outfalls to local water authorities and/or are difficult to process in on-site waste water treatment plants. Dissolved Air Floatation (DAF) provides a solution for removing particles down to 25 µm (or towards 10 µm with chemical dosing) compared to a Saveall which removes particles in the 100µm+ range. However, DAF sludge tends to be generated at around 2 to 8% solids (depending upon the inlet and operations of the DAF, hence there is motivation to consider firstly removing fat to create a tallow product before processing through a DAF and to also consider concentrating the DAF sludge to reduce waste management costs. Hydrocyclone technology (where liquid is pumped into a cone arrangement that applies high centrifugal forces) can separate fat particles towards 15 µm hence providing an opportunity to create a tallow product from a RMP red stream and could also concentrate DAF to a higher solids concentration. Removal of fats from the red stream showed strong technical viability with an estimated 1.2-year payback.