Optimized method and apparatus for treating laundry effluent

The invention relates to the treatment of waste water 100 using a bioreactor 118. The heated wastewater 100 of the Laundry to be cooled before being introduced into the bioreactor 118th The present invention enables an almost complete recycling of the heat energy dissipated for cooling in the laundry 102. Before returning to the laundry, the wash water or the rinsing water is temporarily stored in a first heat-insulated tank. The latched in the first heat-insulated tank wash water or rinse water is circulated through the first heat exchanger, so that a transfer of heat energy from the waste water in the wash water or the rinse water takes place.