SU1763391A1 - Method for biological purification of sewage and equipment for its realization - Google Patents

Description

The invention relates to sewage treatment plants and can be used for the biological treatment of domestic and industrial wastewater.

The known method of biological wastewater treatment. whereby the waste water is mixed in an aerotank with activated sludge in the presence of oxygen, the mixture of purified water and sludge is sent to a flotation cell to separate purified water and sludge, the latter is divided into circulating sludge and excess, and the circulating sludge is fed to the aeration tank.

A device for biological wastewater treatment is known. containing aeration tank with pipelines for supplying wastewater and oxygen, a flotator with a pipeline for discharging purified water, connected to the aeration tank with pipelines for withdrawing sludge mixture with purified water and supplying circulating and excess sludge.

The known method and device have an insufficient degree of water purification due to the supply to the aerotank and the liquid-liquid mixture formed in the flotation cell from the sludge obtained in it and the water in it.

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The aim of the invention is to increase efficiency.

This chain is achieved by the fact that before the separation, the sludge is dewatered, crushed, and the circulating sludge is mixed with a portion of the wastewater fed to the flotation cell.

In order to carry out these operations, the flotation device is made in the form of a tank connected to pipelines for feeding sludge mixture with purified water and draining purified water, as well as to bunkers designed to collect circulating and excess sludge.

The upper edges of the tank walls are located above the level of the mixture of sludge with purified water. In the tank there are belt conveyors with scrapers. Each bunker is equipped with an iodrobitel and a pipeline for supplying a transporting fluid, while the collecting sludge collecting bin is connected to the wastewater supply pipeline.

The drawing shows the flotation cell, a general view.

The flotator is made in the form of a tank 1 and is connected to an aero tank (not shown) equipped with pipes for supplying waste water and oxygen, a pipe 2 for withdrawing a mixture of sludge with purified water and a pipe 3 for feeding a circulating sludge aeration tank. The tank is also equipped with a pipe line 4 for discharging purified water with a valve 5 and a pipe 6 for discharging excess sludge.

The tank 1 is connected to the collecting sludge collecting bin 7 and to the excess sludge collecting bunker 8, and the upper edges of the walls 9 of the tank 1 are located above the level of the sludge mixture with purified water.

The container 1 is equipped with belt conveyors 10 with scrapers 11.

The circulating sludge collection bin 7 is provided with an iodrobitel 12, a conveyor fluid supply pipe 13 connected to the wastewater supply pipe to the aeration tank (not shown), and the excess sludge collecting hopper 8 is equipped with a seed conveyor 14 and a conveying fluid supply pipe 15.

The flotation cell is connected by a pipeline 16, provided with a valve 17, to a vacuum system (not shown).

The seed drums 12 and 14 are made in the form of a fixed 18 and a movable 19 disks, and the movable disk 19 is connected to the drive 20. The device may contain several pairs of such disks

The device works as follows.

Sewage water enters the aeration tank, where sa is mixed with active sludge in the presence of oxygen and is cleaned, and then a sludge mixture is removed through line 2

with purified water from the aero tank to the flotation tank 1, in which the vacuum is maintained.

Sludge claps, which are less dense than water, float to the surface

Water accumulates and condenses in this zone and, pushed by the lower pop-up pops, forms a layer above the surface of the water, which dehydrates between the walls 9 of the tank 1. The thickness of the slabs of sludge dehydrated is regulated by means of valves 5 and 17. Water through the voids between the pops flow down and through the pipeline 4 for the removal of purified water flows to the consumer.

0 Dehydrated activated sludge by conveyors 10 with scrapers 11 is divided into circulating and surplus and sent to recycling sludge bins 7 and 8, respectively, where

5 its grinding between fixed 18 and movable 19 discs. The crushed circulating sludge is transported by waste water supplied through conduit 13 and fed through conduit 3 to the aeration tank, and excess sludge is transported by fluid supplied through conduit 15, and withdrawn via conduit 6 for subsequent use.

The described method and device for its

This embodiment allows to increase the efficiency of wastewater treatment due to the crushing of dewatered activated sludge and its interaction with part of the wastewater on the way it enters the aeration tank.

Claims (2)

1. The method of biological treatment of wastewater, which consists in the fact that the waste water is mixed in an aeration tank with activated sludge in the presence of oxygen, a mixture of sludge with 5 with purified water is sent to a flotation cell, where purified water and sludge are separated, which are then divided into excess and circulating, fed to the aeration tank, characterized in that, in order to increase 0 efficiency, sludge before separation is dehydrated, crushed and circulating sludge is mixed with a portion of the waste water supplied to the flotation cell. 2. A device for biological treatment of wastewater, containing an aeration tank with pipes for supplying wastewater and oxygen, a flotator with a pipeline for discharging purified water, connected to the aeration tank for discharging a mixture of sludge with purified water and a supply pipe circulating sludge, as well as the pipeline for supplying excess sludge, characterized in that the flotation cell is made in the form of a tank connected to the pipelines for feeding the sludge mixture with purified water and draining purified water and with bunkers for collecting circulating and excess sludge. moreover, the upper edges of the vessel walls are placed above the level of the sludge mixture with purified water, the tank is equipped with belt conveyors with scrapers, and each of the bins is equipped with an iodrobetter and a pipeline for transporting the transporting fluid, and the collection sludge collecting bin is connected to the waste water supply pipeline. 13 20 Yu about / H}. X o ;; 16 L Yu 20 15 If / d I