WO1994020425B1 - Improved method for purifying waste water using activated sludge to increase purification yields - Google Patents

Abstract

A method for increasing the purification yield in a waste water purification plant activation tank by means of an activated sludge method, wherein optionally cationized talcum, pyrophyllite, kaolin or mica with a particle size under 100 νm is fed into the biomass in amounts of up to 2.0 g per litre of waste water. A substantial improvement in solid/liquid separation at the outlet of the activation tank as well as increase in the yield of removed carbon, nitrogen and phosphate pollutants are observed even when the plant is operating at medium or full capacity.

Claims

 MODIFIED CLAIMS [received by the International Bureau on 21 September 1994 (21.09.94); claims 6-9 deleted; other amended claims (1 page)] 1 / - Process of purification of waste water type called "activated sludge", to increase the efficiency of purification of carbon pollution, the purification efficiency of nitrogen pollution and possibly the yield d. purification of the phosphate pollution, in which the wastewater is brought into contact with an biomass composed of scrubbing micro-organisms in an activation basin, the treated water is separated from the activated sludge in a decanter, and a fraction of the activated sludge towards the activation pool, said method being characterized in that biomass is mixed with a powder of talc or pyrophyllite or mica so as to cause the formation of composite flocs consisting of grains of talc, pyrophyllite or mica trapped in a bacterial matrix, the activated sludge formed by said composite flocs having a density greater than that of water and being partially continuously recycled increase microorganisms concentration in the activation tank and the residence time of said microorganisms in said basin. 2 / - Method according to claim 1, characterized in that a talc powder, pyrophyllite or mica consisting of particles smaller than 100 microns in size. 3 / - Method according to claim 2, characterized in that a talc powder, pyrophyllite or mica consisting of particles of size between 3 and 50 microns. 4 / - Method according to one of claims 1, 2 or 3, characterized in that mixed between 0.01 g and 2.0 g of talc powder, pyrophyllite or mica per liter of wastewater to be treated entering in the activation pool. 5 / - Method according to one of the claims 1, 2, 3 or 4, characterized in that a talc powder, pyrophyllite or cationized mica is used. DECLARATION UNDER ARTICLE 19 The new claims were limited to lipophilic products: talc, pyrophyllite, mica. These products have an adsorbent power with respect to fats and are known for their lack of affinity for bacteria (the latter being hydrophilic in nature and consequently having an affinity with hydrophilic materials). The effect of constitution of flocs mixed grains of powder / bacteria is very marked for these products and is totally unexpected given their lipophilic property; these flocs of density higher than that of water, allow to increase during recycling the concentration of microorganisms in the pool of activation and the residence time of microorganisms. The fact that the lipophilic products targeted by the new claims lead to an improvement in the purification of carbon, nitrogen and phosphate pollutants, and that this result is significantly greater than that of the hydrophilic products (kaolin), is very surprising and difficult to explain at the same time. 'actual hour. The process of the invention is new compared to the techniques described in the prior documents and therefore implies an inventive step since, from these earlier documents targeting hydrophilic products (kaolin), the skilled person can not deduce the activity products covered by the new claims.