Wastewater treatment and disposal is usually seen as an imposed cost, yet handled in the right way wastewater can be a source of energy, nutrients and reusable water. Here we present full scale industrial wastewater treatment plant case studies in Australia where process heat and high quality water are produced.
The dairy sector is the largest manufacturing sector in New Zealand, and consumes considerable amounts of energy and fresh water. Anaerobic treatment of the dairy wastewater generated results in the production of biogas, which provides a renewable source of energy. Secondary aerobic treatment generates effluent that is clean enough to be discharged into the environment or can be reused in the factory process. The combination of anaerobic and aerobic offers the best effluent quality for the lowest energy consumption.
The case studies include dairy and starch production wastewater in Australia. All production facilities use the ADI Systems ADI-BVF® reactor to anaerobically treat the wastewater, producing an energy-rich biogas. The biogas is used in plant boilers to generate process heat for the site. The anaerobic effluent is aerobically polished by a sequencing batch reactor or membrane bioreactor to further reduce the pollutants in the water prior to final discharge or reuse.