RU2391295C2 - Method for biological purification of waste water from oil products - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to biotechnology, particularly to biological purification of waste water from oil products using active sludge and a biological preparation Destroyl. The method involves addition of Destroyl biological preparation to waste water before the aerotank and to active sludge before the aerotank, where Destroyl is added to the waste water and active sludge in ratio ranging from 3:4 to 4:3.

EFFECT: method increases efficiency of removing oil products.

2 cl, 1 tbl, 10 ex

Description

The present invention relates to wastewater treatment, in particular to methods for biological treatment of water from oil products, and can be used at biological treatment plants.

A known method of purification of oily wastewater in aeration tank by oxidation with activated sludge with the addition of a mixture of cultures of oil-oxidizing microorganisms: Bacillus formosus, Pseudomonas lignefaciens, Bacillus brevis [AC USSR 925875, C02F 3/34]. From the description of the method it follows that the waste water is purified with a content of substances extracted with sulfuric ether, 70-100 mg / l and substances extracted with hexane, 20-25 mg / l with an aeration duration of up to 8 hours. After cleaning, the content of substances is, respectively, not less than 5 mg / l and not less than 1.5 mg / l, and the removal efficiency, respectively, of 92.8-93.8% and 91.6-92.5%, not enough.

Information is known on the biological treatment of domestic and industrial wastewater containing oil products using the microbial culture of the biological product Destroyl [Railway Transport, 2007, No. 11, p.65]. Destroil, manufactured by Sibbiopharm, Berdsk, contains Acinetobacter sp. Culture isolated from nature, which selectively affects hydrocarbons. When a biological product is introduced into an aeration tank filled with purified waters interacting with activated sludge, the oil content in the purified waters decreases slightly (example 2) compared to the control (example 3).

The aim of the invention is to reduce the content of petroleum products in purified waters. The technical result is achieved by the fact that in the method of biological treatment of wastewater from petroleum products using activated sludge and biological product "Destroyl", according to the invention, the biological product "Destroyl" is added to the waste water to the aeration tank and to activated sludge to the aeration tank, the obtained waste water is mixed with the obtained activated sludge, and the biological product "Destroil" is introduced into wastewater and activated sludge in a ratio of 3: 4 to 4: 3. Biological product "Destroyl" is introduced into wastewater and activated sludge in an amount of 1.5-2.0 g per 1 m ^{3 of} water-sludge mixture located in the aeration tank.

Wastewater and activated sludge are sufficiently enriched with nitrogen-phosphorus salts, however, if necessary, the salt concentration is adjusted to 0.002-0.003% by the addition of mineral fertilizers. The temperature of the wastewater should be mainly 18-22 ° C.

Wastewater is treated according to the proposed, known and control methods.

Example 1

Of primary settler collected wastewater volume of 1 m ^3, and from the secondary sedimentation tank - the return activated sludge of 1 m ³ in special tanks, determine the content of nitrogen-phosphorus salt in order to clarify the need for additional application of mineral fertilizers. The temperature of wastewater and activated sludge is 20 ° C. Destroil biological product is introduced into waste water in an amount of 0.9 kg and activated sludge in an amount of 0.9 kg. In total, the amount of the drug added is 1.8 kg (1800 g: 900 m ³ = 2.0 g per 1 m ^{3 of the} water-sludge mixture in the aeration tank). Wastewater with a biological product added is mixed and saturated with air by bubbling for 4 hours (according to the method of use of the drug), the same actions are performed with activated sludge with a biological product introduced into it. The resulting wastewater is mixed with the activated sludge obtained in a non-flow tank, the mixture is fed into an aeration tank with a volume of 900 m ³ , where the supplied mixture interacts with running wastewater and activated sludge during an aeration period of 20 hours. The cleaning results are shown in the table.

Example 2 (known method)

In running wastewater and activated sludge interacting in an aeration tank with a volume of 900 m ³ , a suspension of the biological product "Destroil", pre-activated for 4 hours in the presence of mineral fertilizers and air (according to the method of use of the drug), in the amount of 1.8 kg, is produced cleaning with an aeration period of 20 hours. The cleaning results are shown in the table.

Example 3 (control)

Wastewater treatment in aeration tank is carried out according to example 2 without the use of biological product "Destroyl". The cleaning results are shown in the table.

Example 4-7

Wastewater treatment is carried out according to example 1. The total amount of Destroil biological product introduced into wastewater and activated sludge is 1.8 kg with a dose ratio of 2: 4 applied to wastewater and activated sludge (example 4); 4: 2 (example 5); 3: 4 (example 6); 4: 3 (example 7). The cleaning results are shown in the table.

Example 8-10

Wastewater treatment is carried out according to example 1. The total amount of the biological product "Destroil" introduced into the wastewater and activated sludge is: 0.9 kg (example 8); 1.35 kg (example 9); 3.6 kg (example 10). The ratio of the doses of the biological product "Destroyl" introduced into the wastewater and activated sludge is 1: 1. The cleaning results are shown in the table.

The implementation of the proposed method according to example 1 allows to reduce the content of petroleum products in wastewater when they are cleaned in the aeration tank from 3.80 to 0.134 mg / l, with a removal efficiency of 96.5%. For comparison, the implementation of the known method (example 2) helps to reduce the amount of petroleum products from 4.16 to 0.222 mg / g with a removal efficiency of 94.7%, and the control method (example 3) from 4.42 to 0.275 mg / l, removal efficiency of 93.8%. This improvement in the performance of wastewater treatment for petroleum products is achieved due to the preliminary adaptation of Destroil bio-oxidizing microorganisms to a specific wastewater composition and activated sludge biocenosis and the achievement of the stage of active degradation of petroleum products. The ratio of the doses of the biological product "Destroyl" introduced into the wastewater and activated sludge should be from 3: 4 to 4: 3. At other ratios, the amount of petroleum products in purified waters increases. The total amount of Destroil biological product introduced into waste water and activated sludge should be 1.5-2.0 g per 1 m ^{3 of} water-sludge mixture in the aeration tank. When reduced to 1.0 g / m ³ (example 8), the efficiency of cleaning from oil products decreases, and an increase to 4.0 g / m ³ (example 10) is impractical (efficiency increases slightly).

Table Example The oil content at the inlet, mg / l The content of oil products at the exit, mg / l (oil removal efficiency,%) one 3.80 0.134 (96.5) 2 4.16 0.222 (94.7) 3 4.42 0.275 (93.8) four 4.16 0.183 (95.5) 5 4.16 0.183 (95.5) 6 4.16 0.154 (96.3) 7 4.16 0.141 (96.6) 8 4.29 0.125 (95.0) 9 4.29 0.167 (96.1) 10 4.29 0.159 (96.3)

Claims (2)

1. The method of biological treatment of wastewater from petroleum products using activated sludge and biological product "Destroil", characterized in that the biological product "Destroil" is introduced into the waste water to the aeration tank and activated sludge to the aeration tank, the obtained waste water is mixed with the obtained activated sludge, biological product Destroyl is introduced into wastewater and activated sludge in a ratio of 3: 4 to 4: 3. 2. The method according to claim 1, characterized in that the wastewater and activated sludge biological product "Destroil" contribute in the amount of 1.5-2.0 g per 1 m ³ water-sludge mixture in the aeration tank.