METHOD FOR ADVANCED TREATMENT AND REUSE OF BIOCHEMICAL EFFLUENT FROM CHEMICAL WASTEWATER

Abstract

A method for advanced treatment and reuse of biochemical effluent from chemical wastewater comprises following steps: (1) preparing a highly-loaded Fe.sub.3O.sub.4 magnetic resin by spray suspension polymerization; (2) using the magnetic resin prepared in Step (1) for advanced treatment of the biochemical effluent from chemical wastewater and adding 3˜5 mmol/L H.sub.2O.sub.2 into the biochemical effluent from chemical wastewater for a mixed reaction of 60˜600 minutes; (3) separating solid from liquid firstly in the mixed wastewater after being treated in Step (2), and then disinfecting the separated biochemical effluent from chemical wastewater.

Claims

1. A method for advanced treatment and reuse of biochemical effluent from chemical wastewater, characterized by comprising following steps: (1) preparing a highly-loaded Fe.sub.3O.sub.4 magnetic resin by spray suspension polymerization; (2) using the magnetic resin prepared in Step (1) for advanced treatment of the biochemical effluent from chemical wastewater and adding 3˜5 mmol/L H.sub.2O.sub.2 into the biochemical effluent from chemical wastewater for a mixed reaction of 60˜600 minutes; (3) separating solid from liquid firstly in the mixed wastewater after being treated in Step (2), and then disinfecting the separated biochemical effluent from chemical wastewater.

2. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 1, characterized in that: the volume ratio of the magnetic resin and the biochemical effluent from chemical wastewater is 0.1%˜5%.

3. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 1, characterized in that: the specific surface area of the magnetic resin is 500˜700 m.sup.2/g, the mass fraction of Fe.sub.3O.sub.4 nanoparticles in the magnetic resin is 30%˜50%.

4. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 2, characterized in that: the magnetic resin is prepared by using a nozzle with aperture of 20˜50 μm to disperse uniformly a mixed solution of an oil phase and Fe.sub.3O.sub.4 nanoparticles into a water phase under 0.1 MPa to form an emulsion, heating up to 70° C. for 2 hours' reaction at a stirring speed of 150 r/min and then heating up to 85° C. for 12 hours' reaction, subsequently using deionized water, ethanol, acetone to wash, and finally drying.

5. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 3, characterized in that: in the oil phase, a monomer is divinylbenzene, a porogen is toluene and an initiator is azobisisobutyronitrile, the ratio of divinylbenzene and toluene is 1:2˜1:3 and the mass fraction of azobisisobutyronitrile is 1%.

6. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 3, characterized in that: in the water phase, a dispersant is sodium dodecyl sulfate and polyvinylpyrrolidone, and the ratio of sodium dodecyl sulfate and polyvinylpyrrolidone is 1:3˜1:6, the mass fraction of the dispersant is 0.5%˜2%.

7. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 3, characterized in that: the Fe.sub.3O.sub.4 nanoparticles is oleic-coated modified, the mass ratio of the Fe.sub.3O.sub.4 nanoparticles and the oil phase is 1:1˜1:2.

8. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 1, characterized in that: in the advanced treatment process, the pH value of the mixed wastewater is adjusted to 5˜7 by using hydrochloric acid and sodium hydroxide.

9. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 1, characterized in that: the disinfection is UV and chlorine combined disinfection, being a ultraviolet light and a NaClO disinfectant; the amount of the NaClO disinfectant is 5 mg/L in terms of Cl.sub.2, the ultraviolet light with low pressure mercury lamp as light resource has a UV radiation intensity of 30 W and reaction time of 100˜1800 seconds.

10. The method for advanced treatment and reuse of biochemical effluent from chemical wastewater according to claim 1, characterized in that: it further comprises mixing the magnetic resin resulted from separation in Step (3) with a recycled liquid, which is composed of 5 wt. %˜15 wt. % sodium hydroxide (NaOH), 20 wt. %˜70 wt. % methanol (CH.sub.3OH) or 5 wt. %˜15 wt. % NaOH, 50 wt. % CH.sub.3OH, after mixing the magnetic resin with the recycled liquid for 20˜180 minutes, standing for 55˜65 minutes to separate the magnetic resin for recycling.

Description

DETAILED DESCRIPTION

[0026] In order to make the objectives and advantages of the present invention more apparent, the present invention will be described in detail with reference to the following embodiments. It should be understood that the following words are only the description of one or more specific embodiments of the present invention, not a serious limitation for the protection claimed by the present invention.

[0027] The method for advanced treatment and reuse of biochemical effluent from chemical wastewater is a coupling process of resin absorption, Fenton advanced oxidation and UV-chlorine disinfection, which enriches the refractory organic matters in the biochemical effluent from chemical wastewater through resin absorption, and adds H.sub.2O.sub.2 for Fenton advanced oxidation decomposition under catalysis of Fe.sub.3O.sub.4 nanoparticles, then removes parts of decomposition products through resin absorption and further removes the organic substances remained in solution through UV-chlorine disinfection.

Embodiment 1

[0028] After adjusting pH value of the biochemical effluent of a large chemical wastewater treatment plant to 6, adding magnetic resin and H.sub.2O.sub.2 successively, the volume of the magnetic resin accounting for 2% in the biochemical effluent from chemical wastewater, the concentration of H.sub.2O.sub.2 being 4 mmol/L, and separating solid from liquid after 300 minutes' reaction. Adding NaClO disinfectant of 5 mg/L by Cl.sub.2 into the separated biochemical effluent from chemical wastewater, while opening UV lamp of 30 W for 600 seconds, the water quality of the effluent is shown in Table 1. Finally, mixing the separated magnetic resin with 5 wt. % sodium hydroxide (NaOH), 70 wt. % methanol (CH.sub.3OH) for regeneration, the regeneration time being 130 minutes, then standing for 55 minutes; using the regenerated magnetic resin as a fresh magnetic resin. As shown in Table 1, with reference to the water quality standard for washing water in the reuse of urban recycling water—Water quality standard for industrial uses (GB/T19923-2005), the waste water of this plant meets the reuse standard of recycled water.

TABLE-US-00001 TABLE 1 Comparison of effluent water quality from the method in the present invention with the water quality standard for washing water soluble total residual fecal TOC COD.sub.Cr BOD.sub.5 solid chlorine coliforms index (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (cells/L) effluent from 7.8 20.2 10.8 500 0.3 10 the method for the present invention washing water — — ≦30 ≦1000 ≧0.05 ≦2000 standard for water quality

Embodiment 2

[0029] After adjusting pH value of the biochemical effluent of a large chemical wastewater treatment plant to 5, adding magnetic resin and H.sub.2O.sub.2 successively, the volume of the magnetic resin accounting for 1.5% in the biochemical effluent from chemical wastewater, the concentration of H.sub.2O.sub.2 being 3 mmol/L, and separating solid from liquid after 100 minutes' reaction. Adding NaClO disinfectant of 5 mg/L by Cl.sub.2 into the separated biochemical effluent from chemical wastewater, while opening UV lamp of 30 W for 120 seconds, the water quality of the effluent is shown in Table 2. Finally, mixing the separated magnetic resin with 15 wt. % sodium hydroxide (NaOH), 20 wt. % methanol (CH3OH) for regeneration, the regeneration time being 60 minutes, then standing for 60 minutes; using the regenerated magnetic resin as a fresh magnetic resin. As shown in Table 2, with reference to the water quality standard for boiler supply water in the reuse of urban recycling water—Water quality standard for industrial uses (GB/T19923-2005), the waste water of this plant meets the reuse standard of recycled water.

TABLE-US-00002 TABLE 2 Comparison of effluent water quality from the method in the present invention with the water quality standard for boiler supply water soluble total residual fecal TOC COD.sub.Cr BOD.sub.5 solid chlorine coliforms index (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (cells/L) effluent from 5.9 18.3 7.1 500 0.5 24 the method for the present invention boiler supply — ≦60 ≦10 ≦1000 ≧0.05 ≦2000 water standard for water quality

Embodiment 3

[0030] After adjusting pH value of the biochemical effluent of a large chemical wastewater treatment plant to 7, adding magnetic resin and H.sub.2O.sub.2 successively, the volume of the magnetic resin accounting for 3% in the biochemical effluent from chemical wastewater, the concentration of H.sub.2O.sub.2 being 5 mmol/L, and separating solid from liquid after 550 minutes' reaction. Adding NaClO disinfectant of 5 mg/L by Cl.sub.2 into the separated biochemical effluent from chemical wastewater, while opening UV lamp of 30 W for 1800 seconds, the water quality of the effluent is shown in Table 3. Finally, mixing the separated magnetic resin with 10 wt. % sodium hydroxide (NaOH), 50 wt. % methanol (CH3OH) for regeneration, the regeneration time being 100 minutes, then standing for 65 minutes; using the regenerated magnetic resin as a fresh magnetic resin. As shown in Table 3, with reference to the water quality standard for process and product water in the reuse of urban recycling water—Water quality standard for industrial uses (GB/T19923-2005), the waste water of this plant meets the reuse standard of recycled water.

TABLE-US-00003 TABLE 3 Comparison of effluent water quality from the method in the present invention with the water quality standard for process and product water soluble total residual fecal TOC COD.sub.Cr BOD.sub.5 solid chlorine coliforms index (mg/L) (mg/L) (mg/L) (mg/L) (mg/L) (cells/L) effluent from 9.2 22.3 11.4 850 0.5 18 the method for the present invention process and — ≦60 ≦10 ≦1000 ≧0.05 ≦2000 product water standard for water quality

[0031] To sum up, the method for advanced treatment and reuse of biochemical effluent from chemical wastewater provided by the present invention can, on one hand, effectively enriches the pollutants through absorption by utilizing its higher specific surface area; on the other hand, facilitate Fenton oxidation decomposition by rendering Fe.sub.3O.sub.4 loaded therein as catalyst and can also remove the decomposition products through the magnetic resin by absorption. At the same time, adding additional UV source and chlorine strengthens its oxidation process, and functions as disinfection to kill pathogen, so that the water reuse can be further achieved.

[0032] The implementation of the present invention has been described in detail by above embodiments, but to which the present invention is not limited, for those skilled in the art, after being informed of the description in the present invention, several equivalent modifications and substitutions can be made without departing from the principle of the present invention, these equivalent modifications and substitutions should also be considered as falling within the scope of the present invention.