SU1320177A1 - Method of processing active excessive silt and deposition of primary settlers - Google Patents

Abstract

Sludges resulting from biological purificn. of waste waters which comprise activated sludges or mixed sludges contg. activated sludges and sludges from the preclarification stage are treated. The treatment also includes aerobic stabilisation, compacting and dewatering of the sludge. Aerobic stabilisation takes place in the stabiliser. The level of the sludge is conserved- according to equation (I); hi is the sludge level at time i; Qi is the vol. of sludge to be stabilised at a given time i; in m3/day. P is the nominal time of aerobic stabilisation (day); Fi is the effective area in m2 of the stabiliser at time i; k is dimensionless constant of value 1.05-1.08; Tp is nominal temp. (deg.C) of the sludge in the stabiliser; Ti is sludge temp. (deg.C) at time i.

Description

one

The invention relates1 {TC to the treatment of sludge formed during the treatment of wastewater at bioxide and cleansing stations, in particular, to aerobic stabilization of sludge,

The purpose of the invention is to improve the water recovery properties of stabilized sludge and reduce the cost of

The method is as follows.

The sediment of primary sedimentation tanks before aerobic stabilization is degassed to remove the gas resulting from the partial decomposition (fermentation) of the easily acidified organic matter of the sediments by putrefactive microorganisms during the long residence of the sediment in the primary sedimentation tanks. The main components of the gas (hydrogen sulfide, carbon dioxide gas, methane and others,) have an inhibitory effect on the microflora of the active mother, which leads to a slower process of aerobic stabilization and deterioration of water loss; gh properties of stabilized precipitation

The sedimentation of the primary sedimentation tanks is carried out by aeration. Duration (5-25 min) and intensity (0.5-1.5 h) of aeration depends on the type of sediment, its viscosity, degree of compaction and. Reducing the duration and intensity of aeration does not ensure a sufficient degree of degassing, increasing them increases the air consumption for aeration without improving the process parameters.

Aerobic stabilization is carried out to prevent sediment from rotting and improving its drainage of its properties; The process consists in the biochemical oxidation of the organic part of the sludge and the adsorption of fine and colloidal components by slamming the activated sludge. As a result, the drainage properties of the sediments are improved. By the time of the oxidation of all easily oxidizable organic matter in the sediment, its water withdrawal properties are improved to the maximum extent possible with this treatment method. Further aeration, without changing the stability of precipitation to the action of rotten microorganisms, is accompanied by a deterioration in the water-returning properties of precipitation as a result of the death of microorganisms of actinic sludge,

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its destruction and accumulation of metabolic products in the system. The duration of the aerobic stabilization process depends on the type of precipitation, its proportion, the degree of compaction, temperature, etc., and can be determined based on the experiment: approximate calculations for specific characteristics precipitation. However, at sewage treatment plants, a number of characteristics are constantly changing (the temperature of precipitation in the stabilizer, their flow rate, the number of operating sections, etc.),

The optimal duration of the aerobic stabilization process is maintained by varying the level of precipitation in the stabilizer in accordance with the dependence:

 ()

t f

where h is the precipitation level in the stabilizer, m; O - consumption of precipitation entering

on stabilize, - the duration of the process at the estimated temperature and flow of precipitation, days; Tp is the calculated temperature. WITH; T is the temperature of precipitations; K - bezzerkern koes1h}) search1ekt,

equal to 1.05-1.08%; F stabilizer working area, m

This dependence takes into account the change in 1) the precipitation approach, their temperature, the number of operating sections (when disconnecting a row of sections) and allows maintaining the level of precipitation in the stabilizer, ensuring non-rotting sludge with good water-withdrawing properties.

Primer p. 1., The sediment of the primary settling tanks (PO) with a solids concentration of 48.2 g / l, ash content 30%, specific filtration resistance 1100.10 cm / g degassed azera- for 25 minutes at intensive aeration of 1.5, mixed with activated sludge (AJ-0 with a concentration of 10.2 g / l, ash content of 25.7%, specific filtration resistance of 87.10 cm / g and stabilized when the level of precipitation changes in the stabilizer.

The consumption of precipitation is 1000 m / day at cooTHoiiieinfH L1 1: ON - 1: 2 ,, temperature

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precipitation in the stabilizer is 19 ° С; the working area of the stabilizer is 1080 m.

Aeration is carried out using a compressor unit, the concentration of dissolved oxygen is 2-3 mg / l. The process control is carried out according to the rate of oxygen consumption, the specific filtration resistance (USF), and the concentration of the solid phase.

The stabilized sediments are compacted and dewatered on vacuum filters after reagent conditioning.

The duration of aerobic stabilization () at a design temperature of 14 ° C is 6 days, while the level of sediment and stabilizer is 5, 4 m. The level of sediment in the stabilizer at a precipitation temperature of 19 ° C is calculated by the formula

1000-6. 1 7Q

 -lOSO- 3,79 m.

The precipitation in the stabilizer with increasing temperature from 14 to. 19 C is reduced 1.4 times (from 5.4 to 3.79 m), the duration of the process varies from 6 to 4 days, which is necessary to obtain a non-rotting sludge with good water-withdrawing properties.

The duration of aerobic stabilization for 4 days, the flow rate of air 200, the magnitude of USF decreased to 50-10 ° cm / g, the moisture of compacted sludge decreases to 96.2%, the performance of vacuum filters rises to 26 kg / m.

Example 2. The process of aerobic stabilization is carried out similarly to example 1. The duration of aeration

Compiled by G. Lebedev. Editor L. Pcholinsk. Tehred L. Oliynyk. Proofreader A. Obruchar

          - ™ ------- - --- ------------------ --------- Order 2573/20 Circulation 851 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

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sedimentation of primary sedimentation tanks 5 minutes at an intensity of 0.5. .

The consumption of precipitation is 1000, the ratio of AI: PO is 1: 0.45, the temperature of precipitation in the stabilizer is 15 C, the working area of the stabilizer is 1080 no. The duration of the process at a design temperature of 20 ° C is 3.5 days. The level of precipitation in the stabilizer increases from 3.62 to 4.25 m as the temperature decreases from 20 to 15 ° C.

At the same time, the duration of aerobic stabilization is 4.5 days, the air flow rate is h, the value of GFR is reduced to 4810 cm / g, the moisture of the compacted sludge is 96.5%, the capacity of vacuum filters rises to 28 kg / m h.

The proposed method provides an improvement in the water recovery properties of sediments: the filtration resistivity decreases, the moisture content of the compacted stabilized sediment decreases, and the performance of the vacuum filters increases. As a result of reducing the duration of aerobic stabilization, reducing air consumption, reducing the consumption of reagents for conditioning stabilized sediments before mechanical dehydration and reducing energy consumption, the proposed method becomes cheaper. In addition, the level of precipitation in the stabilizer is automatically maintained, which is necessary to obtain a non-rotting, sediment with good water-diverting properties, taking into account temperature changes and precipitation consumption.

Claims (2)

1. METHOD FOR PROCESSING OVER-ACTIVE Sludge and sedimentation of primary sedimentation tanks, including aerobic stabilization followed by compaction and dehydration, characterized in that, in order to improve the water-discharge properties of the stabilized sediment and reduce the cost of the method, the sedimentation of primary sedimentation tanks before aerobic stabilization is performed by aerobic stabilization and aerobic stabilization a change in the level of precipitation in the stabilizer in accordance with the dependence: where h _T is the level of precipitation in the stabilizer, m; Q - consumption of precipitation entering stabilization, m ³ / day; ΐρ is the stabilization duration at the calculated temperature, days; from Tp - design temperature ^ precipitation in the stabilizer, C; Т - temperature of precipitation, ° C; K is a dimensionless coefficient equal to 1.05-1.08; F is the stabilizer working area, m ² . 2. The method of pop. 1, characterized in that the sediment of the primary sedimentation tanks before aerobic stabilization degassed by aeration for 5-25 minutes at an intensity of 0.5-1.5 m ³ / m ³ h .. 1 13