SU712397A1 - Method of waste water purification - Google Patents

Description

to improve the flotation extraction of oils, and it is impractical to introduce more than 10 g / m, as this does not lead to a significant improvement in flotation cleaning.

The effect of potassium permanganate, introduced by the flotation stage, is reduced to the intensification of flotation extraction of oils by reducing the electric charge of the surface of the oil particles, and since this reagent is an oxidizing agent, there is also a partial oxidation of organic substances contained in the waste water of the coking and chemical industry to intermediate products, which are surface active agents. As a result, the interaction between oil particles, waste water and air bubbles changes, which ultimately leads to an intensification of the process of flotation of selected oils.

The floated oil is removed with the help of strokes and fed for recycling, and the oil-free water is supplied to the averager. Phosphoric nutrition in the form of a solution of phosphoric acid is supplied to the averager.

From the average, the waste water enters the aerotank of the first stage for purification from phenols, the temperature of the waste water is 30-35 ° C, the residence time in the aerotank is 6-7 hours. Then the water enters the aeration tank of the second stage for purification from rohanids, the residence time is 14 h, The wastewater enters the sump.

The method allows purifying wastewaters from coke-chemical production from oils by 65-80%, cyanides by 90-92%, phenols by 99-99.5%, and rodanides by 99-99.3%. After cleaning, the waste water may

to be used to replenish circulating cycles of technical water supply and to extinguish coke.

Example 1. To 1 liter of coke-chemical wastewater (the composition is presented in Table 1) was added 5% KMp04 solution at the rate of 2.5 g / m of wastewater and floated for 15 minutes. The frothy product, into which the oils pass, is removed from the surface of the liquid. After the flotation treatment, wastewater is subjected to biochemical purification, for which phosphorus nutrition is applied at the rate of 10 mg PsOs per 1 liter of wastewater, phenol and rodan destructive culture are sequentially added, and wastewater is aerated, maintaining the temperature at 30 ° C. The duration of biochemical purification is 16 hours. The degree of purification from phenols and rodanides is 99%.

Table I

Example 2. To 1 l of waste water coke production, the composition of which is given in table. 2, a 5% KMp04 solution was added at a rate of 10 g / m wastewater and was floated as in Example 1. The results of flotation are shown in Table. 2. Oil recovery is 80%.

table 2

After flotation, the wastewater is subjected to biochemical purification, the duration of which is 19 hours. The residual content of phenols is 2 mg / l (purity 99.5%), rodanides 1 mg / l (99.3%).

Thus, the use of this method of wastewater treatment provides the following advantages compared with existing methods: reduces reagent consumption by 14-24 times with the same degree of purification from oils, cyanides, phenols, increases the degree of purification from rodanides, and also reduces the amount of utilized sludge.

Claims (2)

1. A method of purifying wastewater from oils, phenols, rodanides and cyanides, including sludge, reagent flotation, the introduction of phosphorus nutrition, averaging followed by biological oxidation, characterized in that, in order to increase the degree of purification from the rodanides, as well as reduce reagent consumption during having the same degree of purification from other components and reducing the volume of the sludge being utilized, potassium permanganate is introduced into the wastewater before flotation. 2. A method according to claim 1, characterized in that the potassium permanganate is introduced in an amount of 2.5-10 g per 1 m of treated water. Information sources, taken into account in the examination 1. USSR author's certificate No. 461065, cl. C 02 C 5/10, 1975. 2. “Coke and Chemistry, 1975, No. 6, p. 36-38 (prototype).