SU971827A1 - Method for processing effluent precipitates - Google Patents

Description

(54) METHOD FOR TREATMENT OF WASTEWATER DRAINS

one

The invention relates more to methods of treating sewage sludge and can be applied in 11 enterprises of processing urban and industrial waters.

A known method of treating sludge is by anaerobic digestion in methane tanks and subsequent recycling. In this method, the sludge from the methanthenkrv is subjected to gravitational compaction, after which part of the sludge is returned (recycled) to the digesters, and the drain water from the compactor is sent for biological treatment 1.

The closest in technical essence and the achieved result to the proposed method is the treatment of sewage sludge by co-compaction of raw sludge from primary sludge pits and excess activated sludge from secondary sludge pits in a lagging vessel, digesting the compaction mixture in the sludge, followed by centrifuge separation. In this method, the fermented and non-fermenting substances are separated on an ip centrifuge and sent for drying, and the fugate silt

centrifuges containing (capable of further fermentation) substances are sent to a plate centrifuge with nozzle ubirpyskoy (separator). On the .od1 separator, separation of the fugate into drainage water, which is sent for bio-logical purification, and condensed product containing substances capable of further fermentation, the latter is sent to the digestion tank for fermentation 2.

The disadvantage of this method is the low efficiency of the process due to the high content of suspended substances in the discharge water.

Compaction of raw sludge (primary clarifiers) and excess activated sludge (secondary clarifiers) to a moisture content of 94–96% requires 8–12 hours or more, i.e. boliP (x volumes of the sinker, which is explained by its not (|) 20 effective coagulation when together with the deposition of particles of excess sludge and wet oc; i4ka, which differ sharply in grunnulstrichesky composition. -397 rum of more than 0.25 mm; 25-15% of particles have a size of more than 1 mm. The particle size of active la particles is generally less than 0.1-0.2 mm. In addition, the volumes of 6 F iCBJBHoro silt and raw sludge (5-10 times); Limiting the possibility of reducing the moisture content of the load with a joint compaction of raw sludge and excess activated sludge in a sludge compactor does not provide the conditions for the most effective retention of suspended substances in wastewater. The aim of the invention is to increase the process efficiency by reducing the suspended solids content in the drainage water. , including compaction of raw sludge and extractable active shea, anazobic digestion, two-stage centrifugation with recirculation, compaction after the first stage of centrifuges Rovani subjecting the mixture of supernatant-uncompacted with excess activated sludge in sootnoschenii by volume of 1: 2 to 1: 5, respectively. The seal was mainly removed for 2–5 hours. The lower limit is due to the need to obtain drainage water, the quality of which will allow it to be cleaned on aeration pads, and not to increase the load on them. Upper P1) was determined by the real ratio of precipitation in osh structures and hegiuns deposits, by considerations. The drawing shows the general scheme of the proposed method. Crude sludge from the primary clarifier enters the trash 2 for anaerobic digestion. The fermentation sediment 3 is divided, centrifugal 4, after which the dehydrated sediment 5 is removed for drying, and the centrifuge 6 is fed to the mixing and co-condensation in the compactor 7 with excess active sludge 3 from the secondary clarifier. A mixture of a centrate is condensed in a nLooPlugger and ground sludge 9 is fed to the separator 10. The drain 11 from the compactor is discharged into aerotanks. The fugate 12 condensed on the separator is returned to the digester, and the overflow 13 is transferred to the azrotec. Example. The process parameters and the quality of the products proposed and known methods are summarized in the table. Concentrations of loaded precipitation by the proposed method are 7 and 8%, while by the known method - 4.3 and 8%. The time of gravitational compaction of precipitation is reduced from 8-12 to 2-5 hours. This allows the body to be effective. use volumes of metxggenk and iluscite. Increasing the efficiency of dry matter retention on the separator from 90 to 96% ensures draining with a quality of 300 mg / l according to the proposed method with a propt 700 mg / l as known, which significantly reduces the load on biological structures.

products

Concentration of sludge entering the methane tank and raw sludge from primary clarifiers,%

The mixture of raw sludge excess activated sludge from iloplotnitel

Condensed upon secondary centrifugation (separation) of the silt mixture

Concentration of sediment, post t1 is about per centrifuge,%

Koktsentratik,%

4.3

2.15

2.15

0.7

0.7

Excess activated sludge concentration,%

The efficiency of retention of dry matter in the secondary centrifuge (separator),%

Concentration of drainage water (given to aero tanks) mg / l

0.5

0.5

90

96

.300

700

Claims (2)

1. A method of treating sewage sludge, including compaction of crude sludge and excess activated sludge, anaerobic digestion, two-stage centrifugation with recirculation, characterized in that, in order to increase the efficiency of the process by reducing the suspended solids in the drain water, compaction after the first centrifugation stage under35 2S accurate activated sludge in the ratio of. 'volume from 1: 2 to 1: 5, respectively. 2. The method according to π. 1, distinguishing * with I in that the compaction is carried out for 2-5 hours