RU2164500C1 - Plant for biologically cleaning natural and sewage water - Google Patents

Abstract

FIELD: systems for biological cleaning of natural and sewage water. SUBSTANCE: plant includes chamber for preliminary biological cleaning and apparatus for biological aftercleaning, housing, charge units arranged in housing and carrying polymeric tubular members with microorganisms secured to said units; apparatuses for supplying and draining water. Housing is provided with system for dispersed distribution of cleaned water along surface area of its cross section. Charge units are oriented by their front walls towards flow of cleaned water. Airlift aerators are arranged in center of charge units; their upper ends are raised over said units, their lower ends are placed under them. System of tubular regeneration aerators is arranged under charge. Relation of areas of cells of net-structure tubular members to areas of their surface is in range (0.2:1)- (0.7:1). It is possible to use polymeric charge with activated carbon applied onto its surface. Polymeric tubular charge may be in the form of tore. EFFECT: enhanced efficiency of cleaning water, lowered energy consumption. 3 cl, 1 tbl, 1 dwg

Description

 The invention relates to the field of biological treatment of natural and wastewater and can be used to solve problems of water supply and sewerage in remote places of development of cottages, cottage neighborhoods, hotels, motels and gas stations, i.e. where there is no possibility of connection to the sewage system.

 A known installation for the biological treatment of domestic wastewater, consisting of a sump with a maintained level of clarified water and a pumping station, biofilters with distribution devices, a mixing chamber with flocculants, a reactor and a block of thin-layer sumps; the installation provides for recirculation circuits of clarified and biologically treated wastewater, as well as sludge from thin-layer sumps through mechanical treatment sumps and an automatic control system (see Austrian patent N 385498, class C 02 F 3/00 of 08.29.86, publ. 11.04.88 g.).

 A disadvantage of the known installation is the complexity of the design of thin-layer sedimentation tanks, uneven distribution of the treated water over the entire area of the biofilter, and a low degree of water purification.

 Known modular installation for biological treatment of domestic wastewater, consisting of devices: pre-treatment, biological treatment, containing at least two rotary bioreactors with tubular loading, each of which contains one submersible biofilter, and purification (see application N 4444514, firms GRUNDMANN, DIETER, DIPL.-PAED.-ING, Germany dated 11/30/94, class C 02 F 3/08).

 A disadvantage of the known installation is the design complexity and reduced reliability of the installation due to the placement of equipment in direct contact with the treated water.

 A known installation for biological treatment of domestic wastewater, consisting of a pre-treatment device - a septic tank-settler for separating suspended matter and biofilm returned from the stage of purification from the settler, a device for biological treatment on an aerated floating granular aeration tank with microorganisms attached to its surface, equipped with membrane aerators installed at the bottom of the aeration tank and circulating water-air flow up from the membranes through the loading layer and down along the side x walls of the aeration tank for the formation of aerobic and anaerobic zones and a device for supplying pre-clarified water, buried in the aeration tank, under the loading layer, as well as a device for tertiary treatment of wastewater - a secondary sump with an air-lift pump in communication with the first septic tank - a sump for draining sediment into it with excess biofilm (see the brochure of the company DYWIDAG-AQUASCHUTZ, Germany "Compact sewage treatment plant for domestic faecal sewage").

 A disadvantage of the known installation are: insufficiently high degree of purification due to the use of granular loading with a relatively small specific surface area, the absence of an optimal regime of biological treatment and post-treatment processes and low reliability of operation.

 A known installation for biological treatment of natural and wastewater, the closest in purpose and technical essence to the claimed one, consisting of a pre-treatment chamber, a biological treatment chamber connected to it, equipped with a loading in the form of polymer tubular elements of various cross-sectional shapes with microorganisms fixed on the loading surface combined in blocks placed in the body of aerators made in the form of diffusers installed at the level of the lower edge of the loading blocks, and mixers, both sintering water saturation with air, mixing and creating a circulating water-air flow through the load, as well as devices for supplying and discharging water; the unit is additionally equipped with a sump for separating the remaining suspension and biofilm with recirculation of the latter into the biological treatment chamber (see RU 2111177 C1, cl. C 02 F 3/06, 05/20/98

A disadvantage of the known installation is: insufficiently high degree of purification for suspended solids - up to 10-15 mg / l, for organic pollutants (BOD _full ) - up to 6-10 mg / l, for ammonia nitrogen - 5-8 mg / l, which is not Meets the standards for the discharge of purified water into a fishery pond and requires additional treatment; high energy costs due to the simultaneous use of aerators and mixers.

 The technical result of the proposed installation is to increase the degree of water purification and reduce energy consumption.

 The technical result is achieved by the fact that in the installation for biological treatment of natural and wastewater, consisting of a preliminary biological treatment chamber and a biological treatment plant, its body, loading units placed in it with microorganisms attached to it in the form of polymer tubular elements, aerators, devices for water supply and discharge, the housing is equipped with a dispersed distribution system of purified water over its cross-sectional area, the loading units are oriented by the front walls to otoku of purified water, airlift aerators are placed in the center of the blocks with the load, their upper ends are raised above these blocks, and the lower ones are recessed under them, the system of tubular regeneration aerators is placed under the load, and the cell area ratio of the tubular elements of the network-like structure to their surface areas is from 0.2: 1 to 0.7: 1.

The opportunity is provided for:
the use of polymer loading with activated carbon deposited on its surface;
perform polymer tubular loading in the form of a torus.

 The drawing shows a plant for the biological treatment of natural and wastewater.

The installation consists of a preliminary biological treatment chamber 1 with devices: for water inlet 2, water outlet 3, sludge discharge - pumps 4 and a device for biological water purification 5, consisting of a housing 6, equipped with:
a distributed distribution system of purified water, made in the form of a distribution tray 7, with overflow windows 8;
loading in the form of polymer tubular elements of a network-like structure with a ratio of the cell areas of the tubular elements to the surface areas of the elements from 0.2: 1 to 0.7: 1 and with microorganisms 9 attached to it, combined into blocks 10, oriented by their front walls 11 towards the flow purified water
placed in the center of blocks 10 with loading 9 airlift aerators 12, the upper ends of which 13 are raised above the blocks 10 with loading, and the lower 14 are buried beneath them;
a system of tubular regeneration aerators 15 located under the load 9;
a device for the release of purified water 16 with bypass windows 17 and
device for removing sludge 18.

Installation for biological treatment of natural and wastewater works as follows:
The source water containing a suspension of 200-300 mg / l and organic substances (BOD _full ) 250-350 mg / l, ammonium nitrogen 25-35 mg / l is fed into the pre-treatment chamber 1 with zones of aeration and sedimentation through the inlet device 2. In In the aeration zone, biochemical purification of water from organic contaminants occurs using microorganisms of activated sludge, where air is supplied to create aerobic conditions and mix. From the aeration zone, the sludge mixture is fed into the settling zone, where activated sludge is separated from the purified water. Active sludge, which has fallen to the bottom in the settling zone, is recycled to the aeration zone by airlift pumps 4.

Biologically purified water with suspended solids - 15-25 mg / l, organic substances (BOD _full ) - 15-25 mg / l, ammonium nitrogen - 5-10 mg / l, in gravity flow through the device for water 3 a device for biological purification of water 5, consisting of a housing 6, equipped with a distributed distribution system of purified water, made in the form of a distribution tray 7 with bypass windows 8, located in the upper part of the housing 6 of the biological purification device 5.

 Such a distributed water supply system ensures its uniform distribution over the cross-sectional area of blocks 10 with a load of 9.

 In the housing 6 there is a loading in the form of polymeric tubular elements of a network-like structure with a ratio of the cell areas of the tubular elements to the surface area of the elements from 0.2: 1 to 0.7: 1 and with microorganisms 9 attached to it, combined in blocks 10.

The tubular shape of the polymer load of the network-like structure 9 with a "highly developed" working surface and with the above optimal ratio of the areas of the cells of the elements to the areas of their surface determines:
effective mass transfer - the supply of water and oxygen to the entire working surface of the load;
high filtering, sorption and retention capacity of the load and provides high concentrations of biofilms, consisting of microorganisms adapted to biodegradation of difficultly oxidized contaminants and nitrifying bacteria, and, therefore, a high speed of the cleaning process and a high degree of water purification.

 It is possible to use a polymer tubular load with activated carbon deposited on its surface, which significantly increases the degree of water purification by increasing the sorption capacity of the load, which ensures removal of specific difficultly oxidized organic compounds from water.

 It is possible to use a polymer tubular loading made in the form of a torus, which significantly increases the degree of water purification by increasing the working surface area of the loading and, consequently, improving mass transfer processes.

 The load 9 is combined into blocks 10 with a rigid frame covered with a grid with cells, which simplifies installation and operation of the device and prevents the load from getting into the airlift aerator 12.

 Blocks 10 are oriented by the front walls 11 towards the flow of purified water. This orientation of the blocks with respect to the flow of the source water ensures the optimal hydrodynamic mode of the process: the directed flow of the treated water passes through the outer layers of the charge 9 from the side of the front wall 11 of the block 10, simultaneously to the charge 9 from the top of the airlift aerator 12 located in the center of the block 10, s the upper end 13, raised above this block, and the lower 14, buried beneath it - “pours out” the water-air flow generated by supplying compressed air to the airlift aerator 12, lifting it up and saturating it evacuated from under the load 9 by the lower end 14 of the aerator 12 of water with oxygen. A water-air flow evenly pouring from the upper end with a reflector 13 of the aerator 12 passes down through the entire volume of the charge 9 and is connected to a part of the stream of purified water moving through the front walls 11 of the block 10 with the load 9.

 The system of tubular regeneration aerators 15, placed under the blocks 10 with a load of 9, with a gap with respect to the lower end 14 of the airlift aerators 12, is a “comb” of perforated tubes and is turned on periodically for intensive aeration, which ensures that the charge 9 is cleaned of excess biofilm, reducing the degree of water purification, and preventing overloading of this load. Airlift aerators 12 can also be installed at the end walls of blocks 10 with a load of 9.

 Two autonomous aeration systems: permanent - airlift and periodic - through a system of tubular regenerative aerators 15, can improve the degree of water purification, since they eliminate the need for constant overly intense aeration of the load 9 and help maintain the optimal concentration of the biofilm.

 The degree of water purification is improved by maintaining the optimal amount of biomass and reducing the removal of suspended solids.

 The created regime of multiple circulation of air-water flow through blocks 10 with a polymer tubular loading of the network-like structure 9 provides an increase in the degree of water purification both by improving the mass transfer between oxygen-saturated water and microorganisms attached to the developed surface of the polymer tubular loading of the network-like structure 9 with the ratio of the area of the cell tubular elements of a network-like structure to areas of their surface from 0.2: 1 to 0.7: 1, and by providing the maximum retention method awns biofilm on the working surface of a highly cellular load 9 with the above characteristic.

 When the ratio of the cell areas of the tubular elements of the network-like structure to the areas of their surface larger than the proposed ones is 0.8: 1 (mesh size more than 10x10 mm), the working surface of the load is reduced by reducing the number of fibers forming a network-like structure of the load 9, which leads to a reduction the amount of immobilized biofilm and, therefore, to reduce the speed and degree of water purification.

 When the ratio of the cell areas of the tubular elements of the network-like structure to the areas of their surface less than the proposed ones is 0.1: 1 (the cell size is less than 3x3 mm), the degree of purification worsens as a result of the slowdown of mass transfer processes due to the rapid overgrowth of small load cells of 9 network-like structures.

 The device for discharging water is made in the form of a collection tray 16 with a number of evenly located bypass windows 17 and is located on the opposite side of the body 6 of the device for deep biological treatment 5 from the water inlet.

Purified water has the following indicators: suspended solids - 1-4 mg / l, organic pollution (BOD _full ) - up to 3 mg / l, ammonia nitrogen - up to 3 mg / l.

 Sludge removal and unloading is carried out if necessary through the device 18.

 Comparative data indicating the optimality of the proposed characteristics of the working surface of the boot are presented in the table.

The proposed installation in comparison with the known provides an increase in the degree of water purification:
for suspended solids - from 10-15 mg / l to 1-4 mg / l;
organic pollution (BOD _full ) - from 6-10 mg / l to 3 mg / l;
for ammonia nitrogen - from 5-8 mg / l to 3 mg / l due to:
creating an optimal hydrodynamic regime of the cleaning process that improves mass transfer - multiple circulation of a water-air flow ascending from the upper ends of the aerators 13, evenly distributed over the surface of the block 10 with a load of 9, and descending (when passing through the entire volume of the load, taking into account the connection with a part of the stream of purified water passing through the front wall of block 10);
the efficiency of mass transfer processes is also facilitated by factors that determine the uniform distribution of water throughout the volume of the load 9 — a distributed distribution system of the purified water, which ensures uniform distribution across the width of the blocks 10 with the load 9, frontal orientation of the above blocks to the flow of the purified water, ensuring uniform distribution over the height of the blocks 10 and, finally, the features of the placement of airlift aerators 12 installed in the center of the load 9 so that the top p 13 was raised above the blocks 10 with the load 9, and the bottom 14 is recessed beneath them and ensure uniform distribution of water over the top surface of the blocks.

 The efficiency of mass transfer processes is also increased due to the use of polymer loading with a "highly developed" working surface and an optimal ratio of the cell areas of the tubular elements of the mesh structure to the surface area of the elements from 0.2: 1 to 0.7: 1.

Only a combination of such features as a dispersed distribution system of treated water, frontal orientation of blocks with loading, features of airlift aerators placement, availability of a system of regenerative aerators and optimal characteristics of the working surface of a network-like loading structure provides deep purification of natural and wastewater, increasing the degree of purification by suspended solids in 10 times, BOD _full - about 3 times and ammonium nitrogen - more than 20 times.

The proposed installation also provides a reduction in energy consumption by 1.2 times and increase the reliability of operation due to:
the use of airlift aerators that provide aeration and mixing at the same time, and when the water is "spilled" from the aerator, it is additionally saturated with oxygen as a result of surface aeration;
the use of a regenerative aeration system of periodic action, in contrast to the mixers in the known device, operating continuously.

Claims (3)

 1. Installation for biological treatment of natural and wastewater, consisting of a preliminary biological treatment chamber, biological treatment plant, its body, loading units placed in it with microorganisms attached to it in the form of polymer tubular elements, aerators, devices for supplying and discharging water, characterized in that the housing is equipped with a dispersed distribution system of the purified water over its cross-sectional area, the loading units are oriented by the front walls to the stream of purified water, e the elevator aerators are placed in the center of the blocks with loading, while the upper ends of the aerators are raised above the blocks with loading, and the lower ends are recessed under them, the system of tubular regeneration aerators is placed under the loading, and the ratio of the cell areas of the tubular elements of the network-like structure to their surface areas is from 0. 2: 1 to 0.7: 1.  2. Installation according to claim 1, characterized in that a polymer charge is provided with activated carbon deposited on its surface.  3. Installation according to claim 1, characterized in that the polymer tubular load is made in the form of a torus.

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