SU1730051A1 - Method of determining depth of active sludge in water - Google Patents

Abstract

The invention can be used to determine the depth of the activated sludge layer in water. The difference in the value of oxygen concentration in two adjacent horizons is measured. The depth of the active sludge layer is set at the mark at which the maximum change in the concentration of oxygen dissolved in water is detected. 1 tab.

Description

The invention relates to methods for controlling the level of sludge in the settling tanks of sewage treatment plants, as well as for controlling sludge in artificial and natural water bodies, and can be used to formulate a process schedule for cleaning in systems of biological treatment of wastewater from industrial enterprises, municipal and agricultural enterprises.

Controlling precipitation levels in sewage treatment plants, in particular, active or secondary sedimentation tanks, is associated with the need both to regulate the concentration of active or aerotanks, and to prevent the transport of activated sludge to purified water. In addition, the control of active sludge deposits is relevant in solving problems of drinking water supply, fisheries and environmental protection in natural water bodies, as well as in the operation of artificial water bodies for various purposes. The visual, mechanical (lot, bathometer, dippers, etc.), instrumental (echo sounder, mutter number, etc.) methods for monitoring the level of precipitation do not provide reliable information about the depth of the activated sludge.

The closest in technical essence and the achieved control result to the proposed is a method of automatic control of the concentration of microorganisms in the waste and natural waters, which involves measuring the parameter correlating with the physiological state of the microorganisms forming the layer of activated sludge, successively across horizons. As such a parameter, the content of dissolved carbon dioxide in water is used, the rate of its release from water is determined, and their concentration is determined by the magnitude of the rate of release of carbon dioxide taking into account the degree of activity of microorganisms in water.

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The disadvantage of this method is the low accuracy of determining the depth of the active sludge layer in water due to the need to measure additional parameters, which complicates the control and introduces additional error in the definition.

The purpose of the invention is to improve the accuracy of determining the depth of the layer of activated sludge in water.

This goal is achieved by measuring the parameter correlating with the physiological state of the microorganisms forming the active sludge layer, successively over the horizons, the difference in the oxygen concentration value of two adjacent horizons being used as such a parameter, and the depth of the active sludge layer is determined by the mark at which the maximum change in the concentration of oxygen dissolved in water was detected.

The method is carried out as follows.

To determine the depth of the active sludge bed, for example, in a secondary clarifier, the concentration of dissolved oxygen is measured over fixed horizons. For measuring the concentration, for example, an oxygen meter is used, the sensor of which is lowered to a depth, or evenly at a given speed, or with stops at specified depths (depending on the inertia of the sensor). At the same time, when the sensor is lowered, the depth of the sensor and the readings of the device, i.e. the concentration of dissolved oxygen at the appropriate depth. For each pair of horizons adjacent to the measurement, the difference in the concentration of dissolved oxygen is calculated. As a result of these measurements and from the calculated differences in the values of oxygen concentrations, the depth of the active sludge layer is determined. This depth is set at a point at which the maximum change in the concentration of oxygen dissolved in water is detected.

Example. The verification of the method for determining the depth of the presence of a layer of active sludge in water was carried out in a secondary settling tank of the treatment facilities of the Shebekinsky chemical plant.

To measure the concentration of dissolved oxygen at various depths of the secondary lavatory, a portable oxygen meter, type Oxymet-1, was used, the sensor of which is connected to a recording device with a marking cable 5 cm away.

Sequentially, starting from a depth of 10 cm to a depth of 420 cm every 10 cm

The concentration of dissolved oxygen was measured. At the same time, samples of activated sludge were taken with a bathometer from the same depth, and the concentration of activated sludge at this depth was determined by the dry residue method.

The difference in the concentration of dissolved oxygen in two adjacent horizons, i.e. the change in the concentration of oxygen dissolved in water, according to the data obtained, was determined by the formula

AP02.

where Dr.O2 is the change in the concentration of dissolved oxygen, mg / l-cm;

p02i is the value of the concentration of dissolved oxygen in the measured horizon, mg / l;

p02Y — value of the concentration of dissolved oxygen in the adjacent previous measurement horizon, mg / l;

h is the distance between the measured horizons, see

Measured results

data on the concentration of dissolved oxygen (02) and the concentration of activated sludge, as well as the calculated difference in the value of the concentrations of dissolved oxygen for each pair of neighboring measurement

horizons are given in the table.

The data in the table indicate that the proposed method allows determining the level of activated sludge in the secondary settling tank to within

5cm.

The method can be implemented using any other oxygen meter. The method can be effectively used in the regulation of the mode of operation of biochemical wastewater treatment facilities, as well as in the cartization of bottom sediments of natural and artificial reservoirs with different bottom profiles.

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Claims (1)

Invention Formula The method of determining the depth of the active sludge layer in water, which involves measuring the parameter correlating with the physiological state of the microorganisms forming the active sludge layer, is consistent across the horizons, characterized in that, to increase the accuracy of determination, the parameter uses the difference in the oxygen concentration over the two adjacent horizons, and the depth of the active sludge layer is set at the mark at which the maximum change in the concentration of dissolved water is detected oxygen.