SU1411292A1 - Method of biological purification of waste water - Google Patents

Abstract

The invention relates to the biological treatment of wastewater and can be used for the complete treatment of municipal wastewater with the purification of biologically treated wastewater from nitrogen and phosphorus. The aim of the invention is to increase the degree of nitrogen extraction while maintaining a high degree of phosphorus recovery while reducing the volume of treatment plants and the coagulant dose. The proposed method of biological wastewater treatment includes sequential treatment in the primary clarifier, aeration tank, secondary clarifier, followed by compaction, dehydration and heat treatment of the sludge. Wastewater treatment in the aeration tank is carried out at a concentration of dissolved oxygen of 4–5 mg / l, the rate of extraction of contaminants is 140–150 g of BOD per 1 g of the ash-free substance of activated sludge, which creates conditions for the maximum increase in activated sludge. The sediment of the primary settling tank, together with the excess activated sludge, is subjected to aerobic-anaerobic treatment, the sludge liquid after compaction and dehydration of the sediment is coagulated, settled and discharged together with the biologically treated wastewater. The cleaning method provides an increase in the amount of total nitrogen removed by 2 times, a reduction in the consumption of coagulant by 80% and a decrease in the volume of biological treatment facilities by 1.5 times. 3 tab. (L with

Description

Yu

QD 1C

The invention relates to the treatment of wastewater and can be used for the complete biological treatment of municipal wastewater with the purification of biologically treated wastewater from nitrogen and phosphorus.

The aim of the invention is to increase the degree of nitrogen extraction while maintaining a high degree of phosphorus recovery while reducing the volume of treatment facilities and the coagulant dose.

The method is carried out as follows.

Wastewater after rough mechanical cleaning is served sequentially.

primary settling tank, aeration tank operating in the mode of maximum increase in active sludge, and secondary settling tank. The sediment from the primary clarifier and excess activated sludge from the secondary clarifier are fed to the aerobic-anaerobic treatment and then to the precipitator. After compaction, the fermented mixture of sediment and excess sludge enters the dewatering unit. As a result of dewatering the precipitate mixture

Your water enters the coagulation unit.

where it is treated with lime, and then sent to a septic tank and dumped along with biologically treated wastewater. The dehydrated sludge is fed to the heat treatment unit and then used as a fertilizer.

The technological scheme provides for mechanical treatment of wastewater {water in the primary clarifier, biological purification in the aeration tank with a regenerator, in the secondary clarifier. the flow rate of air entering the aerogenic and regenerator is measured with a ro-meter power. The content of the suspended substances, the concentration, the PC in the initial and treated waste liquid is determined by the usual methods. The concentration of dissolved oxygen in the wastewater is recorded using an AKP-1 dissolved oxygen sensor.

Table 1 shows the comparative results of studies of the efficiency of nitrogen extraction depending on the concentration of dissolved oxygen in the waste liquid.

Increasing the concentration of dissolved oxygen (more than 4-5 mg / l) ow.

0

0

five

0

five

0 5 0

five

It is impractical from the point of view of purification of waste liquid from nitrogen compounds, since the effect of purification on nitrogen no longer increases. At lower levels of dissolved oxygen, the degree of nitrogen extraction is significantly lower. Concentrated dissolved oxygen is 4-5 mg / l with a specific air flow rate of 24-26 m of wastewater.

To determine the maximum increase in activated sludge, various amounts of contaminants are fed to the treatment due to a change in plant capacity. For each obtained value of the rate of extraction of contaminants, the magnitude of the increase in activated sludge and the corresponding effect of nitrogen cleaning are determined.

Comparative research results are presented in Table 2.

The greatest effect of cleaning on nitrogen occurs when the aerotank is operating in the mode of maximum increase in activated sludge, which amounted to 131 g / m post, wastewater. It. This is due to the fact that the greatest amount of nitrogen compounds is removed from the aerotank only as an increase in the biomass of excess active 1.

In the known method, the work of the aerotank under conditions of the maximum increase in activated sludge is impractical because it leads to an increase in the amount of contaminants in the sludge water that enters the head of the sewage treatment plant,.

The rate of extraction of contaminants is 140-150 g of MIC per 1 g of the ash-free substance of activated sludge, the concentration of dissolved oxygen is 4-5 mg / l.

For each case, the flow rate of the original waste liquid, sludge water, and the volume of the precipitate formed are measured. Take samples of the source water after passing it through; aeration tank, sludge water after compaction and sediment collection. A full chemical analysis of samples is carried out to determine the concentration of contaminants, including, phosphorus, total phosphorus, nitrates, total nitrogen, VPK-, the sludge dose, as well as the coagulum dose for sludge water, as coagula nta use lime. The daily wastewater flow rate in both schemes is 1350MV / day, the flow rate of active sludge is 50% of the daily wastewater flow rate is 675 thousand m / day according to the known method. Activated sludge is kept under denitrification conditions for 12 hours, as a result of which it takes on a blackened color. When microscopic activated sludge anaerobic forms of microorganisms are detected. To restore the oxidative capacity, activated sludge is aerated for hours.

Comparative data are summarized in table 3.

Using the proposed method for treating municipal wastewater, compared with the known, an increase in the amount of total nitrogen removed by 2 times, a reduction in coagulant consumption by 80% and a reduction in the volume of biological treatment facilities by 1.5 phases. F.-formula inventions

The method of biological treatment of wastewater from biogenic elements, including treatment in the primary sedimentation tank, aeration tank, secondary sedimentation tank, followed by compaction, dehydration, drying and incineration of sludge, characterized in that.

In order to increase the degree of nitrogen extraction while maintaining a high degree of phosphorus recovery while simultaneously reducing the volume of treatment facilities and the coagulant dose, wastewater treatment in a nitrogen tank is carried out at. removal rates of contaminations 140-150 g of MIC per 1 g of ash-free substance activated sludge and dissolved oxygen concentration 4-5 mg / l, sediment of the primary settling tank together with excess active sludge is subjected to sequential aerobic-anaerobic treatment, sludge liquid after dehydration and compaction of sediments coagulate defend and shed along with treated wastewater

Table 1

Concentration (dissolved oxygen qi,

 mg / l 2 3 4 5 6

23

39 53 55 55

The rate of extraction of contaminants, g VPKp per 1 g of the ash-free substance of active sludge

Growth of active nla, g / m post, waste

waters

The degree of extraction of nitrogen,%

Table3

Table 2

25,100

140

150 200

70 120 129 131 130

52

74

75 75

Continuation of table 3

51411292

Table 3 sales

Content in the original wastewater,

PoS.

off

Sludge content

water, g / m: Po5

No5-.

The content in the water and after coagulation, g / m:

Rob

No5

Content in treated wastewater

VM:

ROY

"ABOUT

Prod: disgusting table.3

ten

The volume of structures of aerobic-anaerobic stabilization of sieges

Claims (1)

Method of biological treatment of wastewater from nutrients, including treatment in a primary sump, aeration tank, secondary sump followed by compaction, dehydration, drying and incineration of sludge, characterized in that the wastewater in aeration tank is carried out at "·. pollution extraction rates 140 150 g of MIC for 1 g of ashless activated sludge substance and dissolved oxygen concentration of 4-5 mg / l, the sediment of the primary settler together with excess activated sludge is subjected to sequential aerobic-anaerobic treatment ^: sludge liquid after dehydration and sediment compaction coagulates, settles and discharges along with the treated wastewater Table 1 Concentration (dissolved oxygen, mg / l 2 3 4 5 6 The degree of nitrogen extraction,% 23 39 53 55 55 Table 2 The rate of extraction of pollution, g VPK _P for 1 g of ashless activated sludge substance 100 140 150,200 The increase in activated sludge, g / m ³ post, wastewater 70 120 129 131 130 The degree of nitrogen extraction,% 45 52 74 75 75 Table3 Processing scheme Indicators by method famous proposed The daily consumption of wastewater, thousand m ³ / day 1350 1350 The concentration of activated sludge, g / l 2 four Continuation of table.Z ------------ --------------- Processing scheme Indicators by method famous proposed one Duration aeration, h 8.5 3.6 Increase in active sludge, g / m ³ 70 131 Continuation of Table Z ' Continuation of table.Z Processing scheme Indicators by method Soil processing Indicators by method famous proposed famous proposed Content in Outcome 10 Scope of construction waste water aerobic-anaerobic g / m ³ : sediment stabilization R 10 10 ka, thousand m ³ - 140 M 40 40 Coagulant dose Silt content fifteen for circulating water, g / m ³ : 1 □ activated sludge  M fifty fifty (CaO), g / m ³ 1300 - Consumption circulating Ν ₀ δ 220 220 active Silt content ep silt, thousand m ³ 675 675 water after coagulation - Coagulant dose \ for tion, g / m ³ : silt water (according fifty 0.1 CaO, g / m ³ ) - 675 Sludge flow rate, ^Ν οδ Content in- 220 3 25 thousand m ³ Volume of aeration tanks, , 40 40. wall wastewater thousand m ³ 480 200 de g / m ³ : The total consumption of coag ^p about 3 3 Lanta, t / day 200 27 "about twenty 10 Editor N. Gunko