Patent ID: 6245121
Filing Date: 2001-06-12
Classification: B01D,C02F,C05F,Y02A,Y02P,Y02W

Abstract:
A process for a treatment of an aqueous liquid effluent containing organic and inorganic matter and having a solids content of at most 12% by weight of dry matter to obtain a purified liquid phase and a solid organic fertilizer, an organic soil improver, or a combination thereof, which process comprises:subjecting the aqueous liquid effluent to one or more primary liquid/solid separation steps and, optionally, one or more physico-chemical treatment steps to obtain a liquid medium containing no more than 3% by weight of dry matter and having a turbidity of at most 300 NTU and a collection of concentrates containing in total at least 15% by weight of dry matter;subjecting the liquid medium thus obtained to an ultrafiltration or microfiltration step to obtain an ultrafiltrate or microfiltrate containing at most 1% by weight of dry matter and having a turbidity of at most 100 NTU;subjecting the ultrafiltrate or microfiltrate to a reverse osmosis operation to obtain a concentrate and a permeate, the permeate constituting the purified liquid phase;adding and mixing with the collection of concentrates an organic complement in particulate form to obtain a mixture containing from 20 to 40% by weight of dry matter, andaerobically fermenting said mixture until an organic soil improver or an organic fertilizer having a dry matter content of 40 to 60% by weight, or a combination thereof is obtained.