Verfahren zum biologischen Reinigen von Abwasser

In a waste water biological treatment process, the novelty is that: (a) non-dissolved substances are removed by a quantitative membrane separation process before the first aerobic biological treatment stage; (b) the membrane treatment is a single-stage or multi-stage process, the first or last stage of which is filtration, micro-filtration, nano-filtration, ultra-filtration and reverse osmosis; (c) the filtrate arising from the membrane separation process is surrendered to aerobic fermentation, while the membrane process concentrate is surrendered to anaerobic fermentation; (d) the concentrate contains 3-15 % solids by weight; (e) inorganic substances are removed from the filtrate before aerobic fermentation by precipitation or steam stripping; (f) the filtrate is aerobically fermented in a ventilated, fully mixed fermenter, in which the cells discharged from the brew are further cleaned by a filter unit before being returned to the fermenter in whole or in part; (g) the filtrate is ni trified or de-nitrified as required, phosphates precipitated and then discharged to a receiving tank; (h) the biocatalysts discharged from the aerobic fermentation reactor are surrendered to an anaerobic bioreactor and; (i) the concentrate from the membrane separation process and the biocatalysts are surrendered to the same bioreactor. USE - Separation of the waste into organic and dissolved substances. The concentrate is then suited for treatment by aerobic fermentation. ADVANTAGE - The process facilitates the construction of a very compact treatment plant which can be located close to the waste water discharge point. The process improves the energy balance of water treatment.