RU2344088C2 - Method of biological sewage treatment and related installation for implementation thereof - Google Patents

Abstract

FIELD: chemistry, water purification.

SUBSTANCE: invention can be used for biological sewage treatment. Inflow midportion is supplied from distributor box 3 through the pipeline 3.1 to the second section of aeration tank 4.2 with its excess delivered through overflow lip 3.2 to the first section of aeration tank 4.1 where contacts with increased amount of sludge and is supplied through drain port to the second section 4.2 and further to sludge sedimentation tank 5 and post-treatment unit 7. Level in the specified capacities is increased. It is accompanied with decreasing of pipeline 3.1 throughput, while that of pipeline 8.1 increases.

EFFECT: stabilised quality of purified water in increased inflow without control and automation devices.

6 cl, 4 dwg

Description

The invention relates to a method for biological treatment with a changing influx of domestic, urban, some types of industrial wastewater and to a plant for its implementation.

Exceeding the average estimated inflow (discharge) leads to a temporary increase in the hydraulic load on the structures and organic pollution loads on activated sludge, as a result of which the quality of the treated water deteriorates.

Several methods for balancing loads are known.

The simplest of the known solutions, ensuring the equalization of both types of loads, involves the use of control tanks for a part of the flow that exceeds the average, with subsequent supply of them to the treatment plant during minimum inflow hours [(1) SNiP 2.04.03-85 Sewerage. External networks and structures, (p. 6.51-6.53)].

The method is applicable for small wastewater flow rates or frequent and slight excesses of the average flow rate. But, for example, from sanatoriums, small settlements at night, there is practically no sanitation. Some enterprises, including small meat and milk processing, work in one shift. In such cases, the capacity of the storage tank should be significant - comparable to the capacity of biological treatment facilities. Moreover, such a solution is passive from a technological point of view (sedimentation may be provided).

Another known method [(2) Pat. 2158237 RU “Method of biological wastewater treatment and sludge treatment”, IPM 2000, No. 30], which provides equalization of the load on the sludge, provides for the cleaning of a part of the inflow that exceeds the average in the mineralizer and the subsequent, together with the average flow rate, in the aeration tank.

The disadvantages of this method: the biological orientation of the action of the sludge, determined by their composition, is different in the mineralizer and aeration tank, so cleaning the excess flow rate in the mineralizer cannot be quite effective; in technological schemes of treatment facilities, a mineralizer is not always provided for; limitation of the output of mineralized sludge - not earlier than 6 hours after the supply of wastewater to the mineralizer is stopped and the ratio of the quantities of ashless substances entering the mineralizer with wastewater and contained in the mineralized sludge is limited, it makes it necessary to control the process.

The foregoing limits the applicability of the method.

The closest analogue to the claimed device is a device for biological treatment of domestic wastewater, including a tank divided by partitions into a receiving chamber, aeration tank, silt sump, collection well [(3) Pat. 2233247 RU "Method for the biological treatment of domestic wastewater (options) and a device for its implementation (options)", IPM 2004, No. 21 (II h)].

The closest analogue to the claimed method are methods for biological treatment of domestic wastewater, including the supply of these waters to a device for treating domestic wastewater and the withdrawal of purified water (see the above patent RU 2233247).

The disadvantages of the closest analogue: the inevitable accumulation of sediment in the receiving chamber; the need to use a control device, level sensors, means of controlling the operation of airlifts, aerators.

The main disadvantage is the impossibility of stabilizing the contamination of treated water with increased inflow only due to the intensification of aeration, since both types of loads increase.

The purpose of the invention is the stabilization of the quality of purified water with increased inflow by increasing the level (increase working capacity) and the mass of sludge in contact with waste water without the use of control and automation.

This goal is achieved in that the installation for biological wastewater treatment, including a tank divided by partitions into an aeration tank, a sludge sump, is equipped with a mechanical treatment unit to which a distribution chamber adjoins, and the aeration tank is divided into two sections by a partition with a bypass hole in it, the lower part the distribution chamber is connected by a pipeline with a valve to the second section of the aeration tank, and its overflow edge is located above the first, a horizontal silt sump with airlift adjoins the block after-treatment with an aerobic attached microflora, having an outlet pipe with a valve and an overflow edge to the collection well.

The mechanical cleaning unit contains grids with manual cleaning and a horizontal sand trap with gravity removal of sediment.

The mechanical cleaning unit and the distribution chamber are located above the first section of the aeration tank, and the lower part of the sand trap is immersed in water.

The sludge settler is equipped with thin-layer modules with the cross movement of water and sludge, made of film material on a cord frame.

The front and rear walls of the silt sump are perforated over the cross section of the settling zone.

This goal is also achieved by the fact that in the method of biological treatment of wastewater with activated sludge in the aeration tank and a sludge tank, part of the wastewater is sent to the second section of the aeration tank and then to the sludge tank and aftertreatment unit, and the excess is sent to the first section of the aeration tank associated with the second through overflow edges into which activated sludge is recycled and at the same time provide a simultaneous increase in the level in the aeration tank sections and in the sludge settler.

The invention is illustrated by drawings, where Fig.1 is a plan of installation; figure 2 is a vertical section of a distribution chamber; figure 3 is a vertical section of the silt sump; figure 4 is a vertical wall of a prefabricated well.

The installation consists of a tank divided by a vertical partition into two compartments - A and B. The main fractions of the capacity of the compartments are the first and second sections of the aeration tank, respectively.

Above the first compartment A there are: a mechanical cleaning unit 1, 2; distribution chamber 3; silt bowl 6; the first section of the aeration tank 4.1. In compartment B are located: the second section of the aeration tank 4.2; silt sump 5; a post-treatment unit with attached microflora 7; prefab well 8.

Three gratings 1 are sequentially placed in the mechanical cleaning unit (clearances decrease in the direction of water movement, manual removal of sediment). Lattices are placed above compartment A in a tray connected to a horizontal sand trap 2, which has a pipe 2.1 to remove sediment during emptying. The sand trap is partially immersed in the silt mixture of the aeration tank. The distribution chamber 3 is provided with a pipe 3.1 (with a valve) from the bottom of the chamber to the second section of the aeration tank at a minimum level and a overflow edge 3.2 to the first section of the aeration tank. The vertical partition separating the compartments has a bypass hole at the minimum design level (provides the specified quality of purified water with an average inflow) from the first to the second section of the aeration tank. The silt horizontal sump is equipped with airlift 5.1, thin-layer modules 5.2 (cross-movement of sludge water, made of film material on a cord frame) and has front and rear walls perforated along the cross-section of the settling zone. Airlift 5.1 is connected to the sludge bowl 6, which has an overflow edge 6.1 to the first section of the aeration tank and a pipe 6.2 to remove excess sludge.

The operation of the installation is as follows. Wastewater arriving with a changing inflow is filtered through a grate 1 and settles in a sand trap 2, the sediment from which is removed through the 2.1 pipeline.

At a rate of up to medium, the wastewater from the distribution chamber 3 through the pipeline 3.1 enters the second section of the aeration tank 4.2. At the same time, a sludge mixture from the first section enters from the first section through the bypass hole in the vertical partition. The sludge mixture from the second section of the aeration tank passes through the sludge settler 5, the sediment sludge 5.1 is pumped into the sludge bowl 6, from which through the overflow edge 6.1 enters the first section of the aeration tank. (With a minimum inflow, it is advisable to remove excess sludge through the pipeline 6.2). The purified water from the sludge settler enters the after-treatment unit 7 and through pipeline 8.1 enters the collection well 8. During this period, the minimum level is set in the aeration tank sections, the sludge settler and the after-treatment unit. With an inflow to medium in the first section of the aeration tank, the sludge dose is greater than in the second. (In the absence and flow rate to the average inflow, the dose of sludge increases).

When the flow rate is more than average, the middle part of the inflow from the distribution chamber 3 through pipeline 3.1 enters the second section of the aeration tank 4.2, and the excess through the overflow edge 3.2 into the first section of the aeration tank 4.1, where it contacts a high dose of sludge and enters the second section through the bypass hole and further into the sludge sump and tertiary treatment unit. At the same time, the level in the indicated containers rises. (With an increase in the level, the throughput of pipeline 3.1 decreases, and that of pipeline 8.1 increases. During the adjustment period, the valve on the pipeline 3.1 adjusts the distribution of the inflow, and the valve on the pipeline 8.1 minimizes overflows over the edge 8.2. The valves also allow you to adjust the process for a long, for example, seasonal changing the inflow schedule).

Thus, with an inflow of more than average, stabilization is achieved not only for the contamination of the treated water, but also for its consumption, which simplifies, for example, subsequent disinfection.

The simple design of the installation, the lack of control and automation tools increase the reliability of its operation, simplify operation, which is especially true, for example, for rural areas.

In particular, when the wastewater is supplied for cleaning by pumps, the method and installation are guaranteed to stabilize their flow rate and pollution.

The proposals have been developed and the conversion of the obsolete plant at the wastewater treatment facilities in the city of Perevoz in the Nizhny Novgorod Region has begun.

Information sources

1. SNiP 2.04.03-85. Sewerage. External networks and facilities, clause 6. 51-6. 53.

2. Pat. 2158237 RU "Method of biological wastewater treatment and treatment of sludge. IPM 2000, No. 30.

3. Pat. 2233247 RU "Method for the biological treatment of domestic wastewater (options) and a device for its implementation (options)". IPM 2004, No. 21 (II hour).

Claims (6)

1. Installation for biological wastewater treatment, including a tank divided by partitions into an aeration tank, a sludge sump, a collection well, characterized in that it is equipped with a mechanical treatment unit to which the distribution chamber is adjacent, and the aeration tank is divided into two sections with a bypass hole in it , the lower part of the distribution chamber is connected by a pipeline with a valve to the second section of the aeration tank, and its overflow edge is located above the first, a horizontal silt sump with an airlift adjoins the block after-treatment with an aerobic attached microflora, having an outlet pipe with a valve and an overflow edge to the collection well. 2. Installation according to claim 1, characterized in that the mechanical cleaning unit contains grids with manual cleaning and a horizontal sand trap with gravity removal of sediment. 3. Installation according to claim 1, characterized in that the mechanical cleaning unit and the distribution chamber are located above the first section of the aeration tank, and the lower part of the sand trap is immersed in water. 4. Installation according to claim 1, characterized in that the sludge sump is equipped with thin-layer modules with the cross movement of water and sludge, made of film material on a cord frame. 5. Installation according to claim 1, characterized in that the front and rear walls of the silt sump are perforated along the cross-section of the settling zone. 6. A method of biological treatment of wastewater with activated sludge in an aeration tank and a sludge sump, characterized in that a part of the wastewater is sent to the second section of the aeration tank and then to the sludge sump and a aftertreatment unit, and the excess is sent to the first section of the aeration tank connected to the second by means of an overflow edge into which activated sludge is recycled and at the same time provide a simultaneous increase in the level in the aeration tank sections and in the sludge settler.

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