RU2304083C1 - Apparatus for biological purification of sewage water - Google Patents

Abstract

FIELD: equipment for biological purification of sewage water.

SUBSTANCE: apparatus for biological purification of sewage water has housing 1 incorporating balancing tank 4, aeration tank 8 divided by means of vertical partition walls 9 into steps furnished with aeration systems 10 and attached microflora carriers 11, secondary settler 12 with silt sedimentation hopper-accumulator 13, silt sedimentation discharge branch pipe 14, and unit 15 for bactericidal treatment of water. Housing 1 is furnished on the outside with thermal insulation 2 and is divided by means of vertical partition walls 3 into two reservoirs. First of reservoirs is balancing tank 4 having volume equal to at least 4-6 volumes of aeration tank and equipped with two vertical partition walls 5. Second reservoir 6 is equipped with system 7 for maintaining constant temperature and moisture content. Second reservoir 6 incorporates aeration tank 8, secondary settler 12 with silt sedimentation hopper-accumulator 13, branch pipe 14 for discharge of said silt, and unit 15 for bactericidal treatment of water.

EFFECT: reduced sizes, metal usage and manufacture costs of apparatus.

1 dwg, 1 ex

Description

The invention relates to techniques for wastewater treatment and can be used in installations of biological wastewater treatment of low productivity.

A known installation of biological wastewater treatment, containing buildings in the form of containers, including an averager with an aeration system, a primary sump with a silt accumulator, equipped with an aeration system, an aerotank divided by vertical partitions into steps equipped with aeration systems and carriers of attached microflora, made in in the form of vertical flat screens, a secondary settling tank with a silt sediment storage hopper and a branch pipe for its discharge, an aerobic stabilizer (mineralizer) with aeration system and a bactericidal treatment unit for purified water by ultraviolet radiation (RF Patent No. 2158233, M. Cl. C02F 1/40, 9/02, 1999).

The closest analogue to the claimed technical solution is a biological wastewater treatment plant, containing an averager, aeration tank, divided by vertical partitions into steps equipped with aeration systems with carriers of attached microflora, a secondary settling tank with a silt sediment storage hopper and a branch pipe for it, a bactericidal water treatment unit (Pat. RF No. 2239607, CL CO2F 3/00, publ. 10.11.2004).

A disadvantage of the known installation of biological wastewater treatment is that at low productivity (1-10 m ³ / day) it must be placed in a heated building, which significantly increases its size and cost. With the low productivity of the known installation, all its tanks have small volumes (hence, low heat capacity), and the water moves between them at very low speeds, which in winter will lead to complete freezing of the water in the installation and its failure. In addition, in this installation, the cleaning processes are carried out by microorganisms, the vital activity of which requires a temperature of at least 8 ° C (the optimum temperature to ensure maximum cleaning performance is 16-20 ° C).

The technical result of the claimed invention is to reduce the size, metal consumption and, consequently, the cost of the wastewater treatment plant while maintaining maximum levels of wastewater treatment.

In the prototype, the degree of wastewater treatment is provided at least 98-99% for the main controlled parameters (suspended solids and BOD (COD)). BOD is the biological need for oxygen, COD is the chemical need for oxygen. These indicators give a quantitative characteristic of organic substances present in wastewater, since there are tens of thousands of names of these substances. BOD are BOD ₅ , BOD ₂₀ and BOD _full . For example, BOD ₅ = 50 mg / liter, this means that oxygen must be supplied to the sample for 5 days in an amount of 50 mg / liter in order to oxidize organic matter in water. COD is the amount of oxygen needed to burn this organics. The numerical value of COD is always greater than the numerical value of BOD.

The task is achieved in a biological wastewater treatment plant, comprising a housing with an averager, an aeration tank, separated by vertical partitions into steps, equipped with aeration systems and carriers of attached microflora, a secondary sump with a silt sediment storage hopper and its branch pipe, and a bactericidal block water treatment, and the casing is equipped with thermal insulation from the outside, is divided by a vertical partition into two containers, the first of which is an averager and there is a volume equal to at least 4-6 volumes of the aeration tank and equipped with two vertical partitions, and the second capacity is equipped with a system for maintaining constant temperature and humidity and it contains an aeration tank, a secondary settling tank with a silt sediment storage hopper, a branch pipe for it and a bactericidal treatment unit for water.

With a wastewater flow rate of up to 1 m ³ / day, a septic tank can be single chamber, i.e. without partitions, at a flow rate of 1-10 m ³ / day - two-chamber, i.e. with one partition, and at a flow rate of more than 10 m ³ / day - three-chamber, i.e. with two partitions. The more partitions, the better, but this is an increase in metal consumption and cost. Therefore, the optimal number of partitions in the averager is two.

In our design, inside the second part of the tank, to maintain a constant temperature in it, there are two small electric heaters, and a fan with an electric heater is installed on the pipe supplying fresh air to the room (a biological installation, and microorganisms for breathing need oxygen). All this can be done using hot water instead of electricity from the heating system from the boiler room, but at the same time, the dimensions of the heaters will be larger and there will be a danger (in case of an accident, pipe or heater bursting) of flooding a room with equipment located in it, including equipment (blowers, heaters etc.), which is energized.

The drawing conventionally shows a longitudinal section of a biological wastewater treatment plant.

The biological wastewater treatment plant contains a housing 1 with thermal insulation 2, divided by a vertical partition 3 into two containers, the first of which is averager 4, which has a volume equal to 4-6 volumes of the aeration tank and equipped with two vertical partitions 5. This ratio of volumes allows maintain a high degree of purification with low productivity. The second tank 6 is equipped with a system 7 for maintaining constant temperature and humidity and there is an aeration tank 8, divided by vertical partitions 9 into steps, equipped with aeration systems 10 and carriers 11 of attached microflora, made in the form of vertical flat screens, the secondary settler 12, made in the form of a thin layer module, with a silo sludge storage hopper 13 and a branch pipe 14 for its removal and a bactericidal treatment unit 15 for purified water with ultraviolet radiation. The capacity of the averager 4 in the proposed technical solution is both a septic tank, a primary settler, a storage hopper and a sludge mineralizer.

The pipe 14 is connected to the averager 4 through the sludge removal system 16.

The biological wastewater treatment plant additionally has ventilation lights 17, 18 and hatches 19, 20.

The work of the biological wastewater treatment plant is as follows.

Wastewater from the sewage system through the pipeline is sent for treatment to averager 4, where they are pre-treated anaerobically (without oxygen) and mechanically cleaned for 2.5-3 days, or, more precisely, suspended solids are deposited with simultaneous accumulation and anaerobic sludge treatment. During the day, wastewater is supplied unevenly for treatment, during the day their volume is greater, at night much less. If in the known installation the wastewater from the averager entered the primary sump, where suspended particles settled, then in the proposed installation already in the averager 4 sedimentation of suspended particles occurs. From the averager 4, the wastewater flows by gravity to the aeration tank 8, where organic pollution is adsorbed and simultaneously oxidized by microorganisms immobilized (attached) on a special carrier 11 located in each stage of the biological treatment unit. To ensure the vital activity of microorganisms, the aeration tank is constantly aerated with air through an aeration system 10 located below the carriers 11 of the attached microflora. Air for aeration is supplied by a special compressor (blower), equipped with the necessary control unit and automation.

After passing through the aeration tank 8, the wastewater enters a thin-layer secondary clarifier 12, where suspended substances, including waste biofilm particles, are retained. Periodically (every 1-1.5 hours), a short-term automatic inclusion of the system 16 for the removal of the delayed sludge in the averager 4. In this example, the system 16 is an airlift. Such a scheme of the plant’s operation allows, firstly, to provide storage and processing of sediments in one tank, which simplifies their subsequent removal, and, secondly, increases the efficiency of water sedimentation in the septic chamber, since the excess biofilm in this case acts as a reagent, sorbing on its surface, part of the pollution contained in the source wastewater.

After the secondary sump 12, the water in the block 15 is subjected to antibacterial treatment with hard ultraviolet radiation, and then it is diverted to the relief or to the reservoir.

The frequency of sludge discharge from the averager (septic tank) 4 depends on the degree of pollution of the wastewater that has passed through the installation during the billing period and is 1-2 times a year. The accumulated fermented mineralized sludge sludge is removed by a sewage machine through the manhole cover 19 on the averager 4, into which the suction hose of the suction pump is lowered.

Example

Wastewater from the sewage system without separation of gray and fecal effluents with the content of the main pollutants C _BB = 27-138 mg / liter and BOD ₅ = 12-98 mg / liter through the pipeline goes to the averager, which by volume is 4-6 volumes of aeration tank. It is this ratio that allows you to maintain a high degree of purification with low productivity.

Due to the long (2.5-3 days) stay of wastewater in the averager, suspended solids settle and accumulate at the bottom of the averager and at the same time (due to the absence of dissolved oxygen in the water), organic matter decomposes with the participation of anaerobic bacteria (chlamydobacteria, saprophytic fungi, cyanobacteria, Thiobacillus denitrificans, Ps.auruginosa, Pseudomonas flourenscens and many others, developing in the volume of the averager depending on the nature of wastewater pollution and having a wide variety of properties), common which is the consumption of the substrate present in the wastewater for its nutrition, reproduction and selection. That is, there is a decomposition of organic compounds into simple substances, including N ₂ , CO ₂ and H ₂ O.

The number of anaerobic bacteria that are in the averager even with a high degree of conventionality cannot be determined, since their number is a constantly variable quantity, both in terms of species composition and mass, and they are distributed throughout the volume, and unpredictably unevenly. According to their species composition, there can be hundreds or thousands of them with the most incredibly diverse properties, since their selection is ongoing there. The largest particles settle to the bottom of the averager. After 2.5-3 days, the water begins to pour into the aeration tank. The aeration tank contains vertical screens on which microorganisms are attached in the form of a film.

Closer to the screen (where oxygen is practically absent) is the denitrifying species (Thiobacillus denitrificans, Ps.auruginosa, Pseudomonas flourenscens, etc.), and closer to the interface of the film with water, the nitrifying species (Sarkodina, Flagellata, Ciliata, Suctoria, Nematoda, Tardigranda , Rotifera et al.). Microorganisms (bacteria) of a nitrifying species, eating substances dissolved in water, transform them into simpler ones to nitrites and nitrates. Microorganisms (bacteria) of the denitrifying species, eating nitrates dissolved in water, decompose them to molecular nitrogen.

To ensure the vital activity of microorganisms, the aeration tank is constantly aerated with air, maintaining the dissolved oxygen content in water at the concentrations required for each stage (4-7 mg / liter). Wastewater is then fed to a sump.

Only thin-layer sedimentation tanks have an order of magnitude, or even two, smaller in comparison with any other sedimentation tanks.

In it, the suspension of suspended particles and spent biofilm occurs. Periodically, every 1.0-1.5 hours there is a short-term automatic inclusion of airlift. Due to this, pumping into the averager of suspended solids detained in the sump. Such a scheme of the plant’s operations allows for storage and processing of sludge in one tank, which simplifies their subsequent removal and increases the efficiency of water settling in the averager, since the excess biofilm in this case acts as a reagent, sorbing some of the contaminants contained in the source waste water on its surface. After that, the water enters the bactericidal treatment unit of water with ultraviolet radiation. Purified water enters the terrain or into the body of water. The degree of water purification is 98-99%.

This installation is intended for biological treatment of only household (fecal) wastewater.

Thus, the proposed technical solution reduces the size and metal consumption of the station by placing all the elements and cleaning units in a single building.

Claims (1)

Biological wastewater treatment plant, comprising a casing with a homogenizer, aeration tank, divided by vertical partitions into steps, equipped with aeration systems and carriers of attached microflora, a secondary sump with a silt sediment storage hopper and its branch pipe, and a bactericidal water treatment unit, characterized in that the case is equipped with thermal insulation from the outside, is divided by a vertical partition into two containers, the first of which is an averager and has a volume not equal to e 4-6 volumes aeration tank and provided with two vertical baffles and a second container provided with a system to maintain a constant temperature and humidity therein disposed aeration, secondary settling tank with a storage hopper sludge, its outlet nozzle and block the bactericidal treatment of water.