RU2099293C1 - Method of treating waste waters - Google Patents

Abstract

FIELD: waste water treatment. SUBSTANCE: invention relates to bioadsorption waste water purification to remove dissolved and finely dispersed organic matters: petroleum derivatives, fats, proteins, and surfactants. Treatment is accomplished by 2-4-step filtration through charge beds covered with activated sludge. Charge beds are made up of activated carbon and a porous polymer material which alternate with each other at volume ratio 1: (1-3). Total residence time of waste water in bioadsorber is 0.5 to 6.0 h. Waste water may be preliminarily subjected to physical- chemical UV treatment through semipermeable membranes or to flotation. EFFECT: enhanced purification efficiency. 2 cl, 2 tbl

Description

 The invention relates to wastewater treatment technology using physicochemical and bioadsorption methods and can be used in engineering, oil refining, agro-processing enterprises, and in public utilities, where wastewater contains dissolved and finely dispersed oil products, fats, proteins, and surfactants.

 A known method of oxidative biological wastewater treatment by microorganisms cultured on the surface of the particles of a fluidized bed of a nozzle, followed by filtration through a bed of a fixed load (USSR Patent, N 1784035, class C 02 F 3/08. 1991).

 Oxidation of the bulk of organic substances is carried out in the fluidized bed of the nozzle under aerobic or anaerobic conditions, the removal of suspended solids in a dense loading layer. In the zone of the fluidized nozzle, granular activated carbon (GAU) is used, in a fixed layer quartz sand (V. V. Naidenko, Yu.F. Kolesov. Bio-adsorption wastewater treatment. / Water supply and sanitary engineering. 1992, N 10, p. 27 -28) or GAU (VN Shvetsov, K. M. Morozova. Biosorbers promising facilities for deep treatment of natural and waste waters. / Water supply and sanitary equipment. 1994, N 1, p. 8-12 prototype).

 For the implementation of the method, column-type apparatuses are used, the fluidization of the nozzle is ensured by the upward flow of the treated water during its continuous circulation.

 The disadvantages of the method: loss of load GAU due to abrasion of the granules, high energy consumption for water circulation.

 The purpose of the invention: cheaper process while maintaining a high degree of wastewater treatment from organic substances, increasing the efficiency of purification from suspended solids.

This goal is achieved by the fact that the wastewater is preliminarily subjected to physicochemical treatment (for example, flotation or ultrafiltration) to remove large mechanical impurities, emulsified and floating organic substances (fats, oils, oil products) and then fed to the bioadsor, where wastewater passes 2.4 stepwise biofiltration through loading with microorganisms cultured on its surface. In this case, water flows from one stage to another, in contact with alternating loading layers of highly porous polymeric material, for example polyethylene (loading by Irrigation) and granular activated carbon at a linear flow rate of 1.5-5.0 m / h and air flow at aeration of 5-12 m ³ / m ^{3 of} treated water.

 The residence time of the wastewater in the bioadsorber is 0.5-6.0 hours, depending on the amount and composition of dissolved organic substances. The volumetric ratio of the load "Watering" and GAU 1.2: 1.

 In the bioadsorber according to the proposed method, microflora is selected that is specific for each stage of biofiltration, in accordance with the composition of water varying from stage to stage, which ensures a deeper purification of it.

 The regeneration of the load with the removal of excess activated sludge is carried out periodically by sectional water-air washing with a 2-fold increase in air flow.

 Regeneration frequency is set based on the load on organic substances.

Compared with the known, the proposed method allows
to simplify the design of the bioadsorber, while creating the possibility of manufacturing units of the block type;
reduce material costs by partially replacing the GAU load with a cheaper “Watering”;
to reduce the loss of GAU due to abrasion of granules during continuous movement, to reduce the removal of suspended solids with purified water.

 Wastewater treatment is carried out as follows.

The wastewater of a dairy plant, a food processing unit, oil-containing wastewater of a car fleet is subjected to preliminary treatment by ultrafiltration on BTU 0.5 / 2.0 F1 ultrafilters, flotation or settling for 3-4 hours. Then they are passed through 2-4 stages of biofiltration in a bioadsorber divided by partitions into several sections filled with Irrigation or activated carbon loading with a granule size of 1.5-3.5 mm. The free loading volume of “Watering” was 90 ± 2% GAU 50.55%
Biofiltration is carried out at a temperature of 15-25 ^o C, a linear flow rate of 1.5-5.0 m / h, an air flow rate of 5-12 l / l of water, a residence time of the treated water in the biadsorber of 0.5-6.0 hours. Volumetric load ratio "Watering": GAU change within 0.5.3: 1. The results of the treatment of wastewater of various compositions are given in table. 12.

 According to the results obtained, when using a combined load in the bioadsorption unit, the optimal load ratio of the “Polivom” GAU is 1.3: 1, the number of biofiltration steps is 2-4.

 With an increase in the load of Irrigation (the ratio of Irrigation / GAU is more than 3), a longer treatment time for wastewater is required. An increase in the loading of activated carbon (the ratio of "Irrigation" / GAU 0.5), with comparable results in terms of purification efficiency, leads to a reduction in the inter-regeneration period of biofiltration, especially when treating wastewater from food production.

 With an increase in the number of biofiltration steps to 6, no noticeable change in the efficiency of water treatment is observed.

 Biofiltration in the optimal mode of the dairy wastewater after pre-treatment with ultrafiltration ensures a reduction in COD from 0.8-1.05 g / l to 27-39.6 mg / l at a process time of 3-4 hours.

 When biofiltration of wastewater, passed only sludge (COD = 1.5-1.6 g / l), a similar result is achieved in 6 hours

 Biooxidation of petroleum products at their concentration in wastewater within the solubility range (15-24 mg / l) to a residual content of 0.3-0.5 mg / l takes 30 minutes. With an increase in the process time to 60 min, the concentration of petroleum products in purified water does not exceed 0.1 mg / L.

 The content of suspended solids in purified water is 3-25 mg / l.

 The time to establish a stable mode of bioadsorber operation is 14-28 days.

Claims (2)

 1. The method of oxidative bioadsorption treatment of wastewater containing dissolved and finely dispersed organic substances, including treatment with activated sludge cultivated on a charge with continuous removal of purified water, regeneration of the charge and removal of excess activated sludge, characterized in that the waste water is treated with 2 4- step-by-step biofiltration through alternating loading layers made of activated carbon and porous polymer material “Irrigation” taken in a volume ratio of 1 1 3 with total the residence time in the bioadsorber is 0.5 6.0 hours  2. The method according to p. 1, characterized in that the wastewater is preliminarily subjected to physicochemical treatment, for example by ultrafiltration through semipermeable membranes or by flotation by known techniques.

Images