Wastewater recycling in small laundries using MBR-technology

Аннотация

The operation of laundries in Germany is characterized by high water and energy consumption. The business competition, increase of energy cost and active legislative requirements provide for growing demand for wastewater reuse systems (for process water treatment, heat and chemical recovery). In relation to the washing technology the level of water saving is rather high. However, the consumption of fresh water cannot be reduced unless the technologies of wastewater treatment and reuse have been integrated into the existing system. There are few if any examples of using wastewater reuse technologies for small laundries with a capacity of less than 500 kg/day; whereas the available water recycle systems are not efficient enough. A membrane bioreactor with flat submerged ultrafiltration membranes was installed at one of such laundries. The operation of the bioreactor provided for 93% COD reduction, and 90% water return. The quality of permeate was very high (it did not contain suspended solids or microbes) and met the requirements to the reuse in washing process. The cost analysis showed that the use of available permeate heat instead of electrical energy improved the economic efficiency of the laundry operation.

Ключевые слова

ultrafiltration , heat utilization , membrane bioreactor , laundry wastewater , water recycling , industrial wastewater treatment