SU258933A1 - A METHOD FOR CLEANING FLOWS CONTAINING SEWAGE WATER - Google Patents

Description

This invention relates to the field of the biological treatment of phenol-containing wastewater, in particular the effluent from coking plants.

The well-known one-stage method for the purification of phenol-containing wastewater consists in mixing the latter with domestic wastewater in aeration tanks and subsequent aeration of the treated effluent, as a result of which organic impurities are oxidized. However, it is impossible to bring the content of phenols in purified water to below tenths of mg / l, which makes it necessary to dilute the effluent discharged into the water body a hundred times.

The proposed method differs from the known ones in that the process is carried out in two stages, in the first of which phenol-containing and household drains are shifted to a 1: 1 ratio and aeration is carried out to a residual phenol content of 1 G / l, and in the second stage the resulting drains are mixed with new a portion of domestic wastewater, followed by aeration of wastewater.

This allows the wastewater to be completely purified from phenols, simplifies the process by eliminating the stage of diluting the effluent when it is discharged into water bodies and intensifies it due to the introduction of additional biogenic and easily oxidizable organic wastewater into the second stage.

contaminants, as well as creates favorable conditions for the formation of activated sludge (its mineralization and removal from the system are excluded).

Example. Phenolic wastewater, in particular the effluent from coke plants, containing various organic contaminants in significant concentrations, is discharged in two stages. For this start

the aeration tank does not serve the entire amount of household wastewater that was started for treatment, but only part of it that provides the minimum permissible dilution of phenol-containing wastewater 1: 1, and the remaining domestic wastewater

are introduced at a specific point along the length of the aerotank, where the termination of phenol up to about 1 mg / l (end of the first and beginning of the second stage). Activated sludge is also supplied to the beginning of the aerotank together with a mixture of phenol-containing and domestic waters. Purified effluent and activated sludge are separated in a secondary settling tank. The clarified water is dumped, and active sludge is fed to the top of the aero tank. Necessary

aeration time is calculated as follows.

The time / 1 of aeration required to reduce the concentration of phenols to 1 mg / l is found in the formula

3

where y is the initial concentration of phenols in the mixture of industrial and domestic wastewater supplied to the beginning of the aerotank. The ti value determines the entry point into the aero tank of an additional amount of domestic wastewater. The magnitude of the MIC purified in the first stage of the mixture of wastewater LI, are found by the formula

LI 168.93 u-115.41 mg / l. (2)

The aeration time in the second stage of the process, i.e., after the introduction of an additional amount of domestic wastewater (), is calculated but the formula

Li / n +

2nd t + n

ty -

hour.

KI

LZ - MIC domestic wastewater, g / mz;

t - consumption of a mixture of phenol-containing p

domestic waste water in the first stage

cleaning, mU / hour; K - air utilization factor

(determined by SNiP P-D.6.62);

the intensity of aeration (taken equal to 6.8 MZJM hour);

a coefficient depending on the total ratio of incoming phenol-containing and household wastewater treatment (determined from the attached table 1).

Table 1

The average cleaning rates for the proposed method of a mixture of coke and household wastewater are summarized in table. 2

table 2