SU814900A1 - Method of thickening microbic biomass from active silt suspension - Google Patents

Description

I The invention relates to microbiological, food and other industries, and more particularly to technological processes for obtaining microbial biomass, in particular activated sludge.

A known method of thickening microbial biomass of eggs of a suspension of activated sludge, including mechanical, dehydration using sludge compactors. silt sites and further drying in natural conditions or in special dryers [1].

The disadvantage of this method is the low degree of thickening with 15 mechanical dehydration of a suspension of activated sludge (50-80 g / l). The supply of a suspension of activated sludge with a biomass concentration of 50-80 g / l and a dryer leads to a sharp increase in the cost of the finished product, as well as to large losses of biomass.

The purpose of the invention is the intensification of the process of mechanical dehydration of a suspension of activated sludge and * 5 reducing the loss of microbial biomass during drying.

The goal is achieved by the fact that before the mechanical dehydration,> 30 mineral substances are introduced into the suspension of activated sludge, which possess the properties of a coagulant and yeast as a flocculant.

In addition, iron and aluminum salts or a mixture of aluminum and iron salts and calcium salts are used as mineral substances.

In this case, the mineral coagulant is chosen not only taking into account the harmlessness of the action when using the finished product, but also taking into account the beneficial use of mineral compounds. When using activated sludge, for example as a fertilizer, it is useful to use substances such as ammophos, lime and other compounds.

The concentration of added mineral compounds is from 100 mg / l to 16 g / l. To intensify the coagulation process, in addition to mineral coagulants, yeast Candida gull liar mondi i s is added to the suspension of activated sludge in the form of aqueous suspensions with a biomass concentration of 15-18%. The amount of added yeast is 160-1800 mg / l or per weight part of the microbial biomass of active sludge - ^ j - weight, part of the yeast.

At high concentrations of mineral coagulant in combination with yeast in a suspension of activated sludge, it is possible to obtain a dense precipitate when the suspension settles in a gravitational field up to 40-50 g / l. After sedimentation, the resulting precipitate is sent to a separator, a torus, where an additional thickening of the microbial biomass to IO14 0 g / l occurs. The thickened suspension is fed to a dryer. The finished product after su-. _s shilka has a moisture content of 3-5% and can be obtained both in finely divided form and in granular form. ”The shelf life is practically unlimited.

The proposed method is illustrated by 15 example.

A suspension of activated sludge with a biomass concentration of 11 g / l from the secondary settling tanks of treatment plants is fed to a mixer, in which jg the suspension is contacted with reagents; potassium chloride, iron, yeast with a concentration in suspension of 8 g / l, 0.3 g / l, 3 g / l, respectively.

After mixing with the reagents, a suspension of activated sludge is subjected to mechanical dehydration, first in settling tanks and then in separators. The suspension to be dried has 116 g / l biomass. In a fluidized-bed dryer, losses amount to 4% of the amount by-30 of the supplied biomass. The finished product is obtained in granular form.

According to the known method, a suspension with a concentration of 28 g / l is fed into the spray dryer, the loss on drying is .9%.

The technical and economic effect of the invention is to reduce the cost of the product by 10-15%, as well as to significantly reduce the loss of microbial biomass of activated sludge during drying "

Claims (1)

I The invention relates to microbial, food and other areas of use, and more specifically to the technological processes of obtaining 1F1 microbial biomass, in particular activated sludge. sludge beds and further drying under natural conditions or in special dryers l. The disadvantage of this method is the low degree of condensation during mechanical dewatering of a suspension of activated sludge (50-80 g / l). The supply of a slurry of activated sludge with a biomass concentration of 50-80 g / l to the dryer leads to a dramatic increase in the cost of the finished product, as well as to a large loss of biomass. This goal is achieved by the fact that mineral substances with coagulant properties and yeast as flocculant are introduced into the suspension of activated sludge before mechanical dehydration. In addition, as the mineral substances, salts of iron, alumina, or a mixture of salts of iron and iron, calcium and calcium are used. In this case, the mineral coagulum is chosen not only taking into account the non-harmful effect; when using the finished product, but also taking into account the beneficial use of general compounds. When using activated sludge, for example, as a fertilizer, it is useful to use substances such as gnosufos, lime and other compounds. The concentration of added mineral compounds is from 100 mg / l to 16 g / l. In order to intensify the production of coagulation, in addition to the extravascular coagulants, Drug Candi gul 1 I ler mondii is added to the suspension of active sludge in the form of aqueous suspensions with a concentrated biomass of 15-18%. The amount of e1 "added is yeast is 160-1800 mg / l or one weight part of the microbial biomass of active t. -1 weight, part of the yeast. sludge 300 1G At high concentrations of mineral coagulant in combination with yeast in a suspension of active sludge, it is possible to obtain a dense sediment when the sludge suspension in the gravitational field is up to 40-50 g / l. The precipitate formed after settling is sent to a separator where additional condensation of microbial biomass to 110140 g / l occurs. The thickened suspension is fed to the dryer. The finished product after sous-. Shilka has moisture and can be obtained both in fine form and in granular form. The shelf life is practically unlimited. The proposed method is illustrated by an example. A suspension of activated sludge with a biomass concentration of 11 g / l from secondary settling tanks of treatment facilities is fed to a mixer, in which the suspension is contacted with reagents: potassium chloride, iron, and yeast with a concentration in suspension, respectively 8 g / l, 0.3 g / l , 3 g / l. After mixing with the reagents, the slurry of active sludge is subjected to mechanical dehydration, first in the backs and then in the separators. The supply for drying the suspension has 116 g / l of biomass. In a fluid bed dryer, the loss is 4% of the amount n of feed biomass. The finished product is obtained in granular form. By a known method, a suspension with a concentration of 28 g / L is supplied to the spray dryer (loss on drying is 9%. The technical and economic effect of the invention is to reduce the cost of the product by 10-15%, and also significantly reduce the loss of microbial activated sludge biomass when drying .. Claim 1. Method for thickening microbial biogas from a slurry of active sludge, including ... mechanical dehydration and drying, characterized in that, in order to intensify mechanical dewatering and reduce losses during: drying ke, mineral substances are introduced into the suspension of active sludge prior to mechanical dehydration, possessing coagulant properties to yeast as flocculant 2, The method according to claim 1, distinguishing to and with the fact that iron salts are used as mineral substances aluminum, or a mixture of aluminum sapay and iron, calcium salts. Sources of information taken into account during the examination 1. Golovovsk. EC, Biological basis of water purification. M. f Higher School, 1978, p. 232.