This abattoir’s ancient activated sludge system needed complete refurbishment requiring the aeration tank to be drained.
A characteristic of the waste water is its consistently very high ammonia concentration.
The activated sludge system has to achieve a final effluent of 20 mg/l BOD, 10 mg/l ammonia and 30 mg/l suspended solids.
The authorities required that this standard be achieved at all times with no concessions for out of spec discharges during re commissioning. To overcome this, during the first few days of the start up process, a proportion of the untreated waste water was tankered away and the plant was re commissioned on a “fill and draw” basis using the final settlement tanks as reservoirs for the partly treated effluents.
Bio-Systems Europe manufactured bacteria products, EU10Startup and EU1000 were the products applied here. These materials were added over 5 days. After three further days the ammonia standard had been achieved. Subsequent BOD and SS analysis demonstrated that these requirements were also being met.