The existing aerobic treatment plant at Bulmers has been upgraded with an anaerobic pre-treatment process for the total effluent. The effluent comes from the bottling lines for cider and other beverages. The main COD load comes from crushing of apples for the cider production.
The effl uent passes through a rotating sieve for removal of bigger particles from the crushing process and is thereafter collected in an equalisation tank. The anaerobic process is a high rate expanded granular sludge bed consisting of a neutralization tank, an anaerobic reactor with a bottom distribution system, a three-phase separator and a sludge granular storage tank. pH adjustment can be achieved by dosing NaOH. Trace elements and nutrients can be added to optimise the process. An overall COD reduction of 85 % has been guaranteed and achieve. by a good margin. After the anaerobic pre treatment, the cider effl uent is led to the existing aerobic treatment plant before it is discharged to the municipal sewage treatment. The biogas from the anaerobic treatment is utilized in a boiler for heating of the incoming wastewater. A pipe for the biogas transport to the existing boiler in the factory is under construction and the biogas will thereafter replace a part of the oil as fuel.