KR20080100899A - Method for preparation of alternative water for agriculture from wastewater effluents using gamma-ray irradiation and calcium exchange method - Google Patents

Abstract

A method for manufacturing alternative water for agriculture from outflow water of a sewage disposal plant is provided to fundamentally prevent contamination of the hydrosphere ecosystem by efficiently processing the effluent discharged into a stream or river without separate treatment. A method for manufacturing alternative water for agriculture from outflow water of a sewage disposal plant comprises the following steps of: irradiating gamma-rays of 0.1 to 100kGy, emitted from radioactive isotopes, on the water discharged from the sewage disposal plant; and passing zeolite(5), obtained by replacing Ca^++ ion on an electric charge part with respect to a sample. The radioactive isotopes are cobalt(Co, atomic number:60).

Description

Method for preparation of alternative water for agriculture from wastewater effluents using gamma-ray irradiation and calcium exchange method}

Figure 1: Overall process diagram of removal of harmful components in effluent water from sewage terminal treatment plant

* Explanation of symbols for the main parts of the drawings

 (1) Effluent inflow pump

 (2) gamma irradiator, (2a) gamma irradiator frame

 (3) ON-OFF valve for effluent inlet

 (4) zeolite reactor

 (5) zeolite

 (6) washing water tank, (6a) washing water supply pump

 (7) hydrochloric acid tank, (7a) hydrochloric acid supply pump

 (8) Calcium Tank, (8a) Calcium Supply Pump

 (9) Cleaning water discharge pump, (9a) Cleaning water ON-OFF valve

(10) Discharge treated water ON-OFF valve, (10a) Discharge treated water piping

(11) Bubbling Fans (11a) Bubbling Diffusers

The present invention relates to a method for producing an alternative agricultural water by removing pathogenic microorganisms, residual organic pollutants and sodium ions from the sewage treatment plant effluent, and more specifically, is released from the cobalt radioisotope from the sewage treatment plant effluent. It is to develop technology to secure alternative water for agriculture by efficiently removing sodium ions by using calcium and sodium substitution reaction after completely sterilizing pathogenic microorganisms and decomposing and removing residual organic pollutants by examining gamma rays.

In Korea, there are many cases of drought damage due to lack of agricultural water from April to May when farming begins. Although sporadic, it is commonly reported to suffer drought damage every two to three years. In order to solve the shortage of agricultural water, the government is promoting the development of agricultural water and the construction of multi-purpose dams, but it also has the disadvantage of causing new environmental problems.

However, in the sewage treatment plant, the effluent contains not only pathogenic microorganisms such as Salmonella, but also persistent organic pollutants, including endocrine barriers with various carcinogenic and mutagenic properties, which can cause great damage to fish and livestock. Can bring The effluent also contains a significant amount of sodium ions, which can be used directly in cropland, resulting in a qualitative decline in cropland soil. Therefore, the hazardous components contained in these effluents must be completely removed before they can be used as alternative water such as agricultural water.

According to a report by Jae-Young Cho (2006), when the groundwater and sewage treatment plant effluent were treated in the field crop fields, the sodium content in the soil was more than three to four times higher than that of the general groundwater. This resulted in excessive concentration of sodium in the soil when continuous discharge of sewage treatment plant effluent from the sewage treatment plant without the removal of sodium ions. In addition to the poor quality of sodium, ionic toxicity of sodium itself may also occur, so if the sewage treatment plant effluent is used as irrigation water in farmland, there should be a way to control the soil salting due to the concentration of sodium.

Korean patent (20-0276379-0000) exemplifies a heavy water treatment system that recycles general household sewage into heavy water by combining biofilm method and advanced oxidation treatment method, and recycles it into domestic water, and Korean patent (10-0330923). -0000) illustrates the wastewater treatment system using anaerobic, aerobic contact circulation method and attached filtration method and a method thereof, and the Republic of Korea Patent (10-0325722-0000) illustrates the treatment method of wastewater using ozone and high concentration oxygen. In addition, Korean patent (10-0446041-0000) discloses the wastewater generated at industrial sites as heavy water by combining rotary biofilm method, activated carbon and activated carbon adsorption filtration method, sand filtration method and advanced oxidation process. A heavy water treatment system that treats and recycles water for domestic use is illustrated. Korean patent (10-0467396-0000) discloses a sewage treatment plant outlet. The effluent water treatment method is illustrated through inflow of branched raw water through ozone contact, and the Republic of Korea Patent (10-0469317-0000) illustrates an advanced wastewater treatment system using ozone, and the Republic of Korea Patent (10-0473651-0000) For example, a water treatment apparatus and a water treatment method for removing contaminants contained in various wastewaters such as industrial wastewater or domestic sewage using ultrasonic waves and photocatalysts are described. The Korean patent (10-0454416-0000) is used in kitchens and bathrooms. The sewage treatment system exemplifies the sewage treatment system to be used as a toilet and treatment water for toilet toilet treatment, and the Korean patent (20-0305457-0000) describes a biological treatment step for treating domestic sewage and other wastewater. Example of advanced wastewater treatment system that removes various untreated pollutants in the rear stage and purifies them. The Korean patent (20-0285740-0000) exemplifies a treatment system for using domestic sewage as river maintenance water, and the Korean patent (10-0550976-0000) treats sewage effluent containing a high concentration of salt. Sewage effluent treatment system and treatment method for producing agricultural water, industrial water, dry water maintenance water, groundwater reclaimed water, and indirect drinking water are described in detail. It is composed of a pretreatment process that produces primary treated water by removing the wastewater, and a backwash type microfiltration process that produces secondary treated water by filtering unfiltered foreign substances that are not filtered in the pretreatment process.

Korean Patent (10-0399153) describes the process of converting sewage or wastewater treatment water into industrial water using gamma rays. More specifically, the process of removing suspended solids using sand filters and the process of gamma ray irradiation By dissolving dissolved organic matter, color and microorganism at the same time, and removing inorganic ions using ion exchange resin to convert to industrial water.

Sodium ions are removed to prevent soil salting, and other organic pollutants or microorganisms are removed to convert to alternative agricultural water.

An object of the present invention is to irradiate gamma rays emitted from cobalt radioisotopes to effluents in a sewage terminal treatment plant in an appropriate dose to decompose and remove residual organic contaminants such as pathogenic microorganisms and endocrine disruptors, and sodium contained in a large amount of effluent water It is to develop alternative water that can be reused as agricultural water by removing sodium ions through substitution reaction with calcium.

The present invention consists of a process for removing pathogenic microorganisms contained in the effluent of sewage treatment plant, gamma-ray irradiation process for controlling residual organic pollutants, and a process for completely removing sodium ions contained in high concentration in the effluent through substitution reaction with calcium ions. It is.

More specifically, the present invention includes the following steps.

Irradiating 0.1 to 100 kGy of gamma rays emitted from radioisotopes to the sewage treatment plant discharged water; And

A process for treating effluent from sewage terminal treatment plant in which the sample is passed through a zeolite prepared by substituting Ca ⁺⁺ ions at a charged site.

The radioisotope is preferably cobalt (Co, atomic number: 60), and may be used bentonite particles known to have excellent cation charge capacity instead of zeolite.

Hereinafter, the present invention will be described in detail with reference to FIG. 1.

Zeolite (particle diameter 2mm) is filled in the zeolite reactor 4 and calcium is supplied to the calcium supply pump 8a to soak for 48 hours to replace Ca ⁺⁺ ions at the zeolite charged site.

The effluent discharged from the sewage treatment plant is transferred to the effluent inflow pump (1) to remove residual organic contaminants such as pathogenic microorganisms and endocrine disruptors by the gamma irradiation device (2) installed in the effluent inlet.

The effluent water passed through the above process is removed through the zeolite reaction tank 4 by discharging sodium ions distributed in high concentration in the effluent by substitution reaction with calcium ions charged in the zeolite, and the treated effluent may be discharged into rivers or rivers. It is separately sent to each supply source such as an agricultural water storage facility or a reservoir through the discharge treatment water pipe 10a.

The process of substituting calcium on the zeolite surface is further described as follows.

When Ca ⁺⁺ ions of the zeolite filled in the zeolite reaction tank 4 are replaced with Na ⁺ ions, the effluent inlet pipe is turned on and off with the on-off valve (3) and the effluent treatment water on-off valve (10), and the washing water is turned on. The OFF valve 9a is closed, and the washing water and the hydrochloric acid are supplied to the washing water supply pump 6a and the hydrochloric acid supply pump 7a to blow air into the bubbling fan 11 through the bubbling diffuser 11a. After washing Na ⁺ and other foreign substances substituted in the zeolite while bubbling, the washing water ON-OFF valve 9a is opened and the washing water discharge pump 9 is operated and discharged.

When the rinsing water is completely discharged, the rinsing water ON-OFF valve 9a is closed, and calcium is supplied to the calcium supply pump 8a, soaked for 48 hours, and replaced with a zeolite charged with Ca ⁺⁺ ions. When the replacement is completed, the effluent can be treated from the initial stage by closing the washing water ON-OFF valve 9a and opening the effluent water ON-OFF valve 10 to start the effluent inflow pump 1 to supply the effluent. Can be. The system consists of a cleaning train and a treatment train, as required, to allow for continuous processing.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are illustrative of the present invention, and the content of the present invention is not limited to the examples.

<Example 1>

The experiment was carried out by collecting the discharged water discharged from the sewage treatment plant in Jeonju-si, Jeollabuk-do with a 20 liter plastic container and refrigerated. After the effluent was transferred to a 4 liter water sample container, gamma rays (cobalt-60) were investigated at 1, 3, and 5 kGy levels at the Advanced Radiation Research Institute in Jeongeup, Jeollabuk-do, Korea. Irradiating gamma rays to a system produces highly reactive species such as hydrated electrons, H, OH, and hydrogen atoms, which are responsible for redox reactions, decomposition of residual organic pollutants, and sterilization of pathogenic microorganisms. Can be performed.

<Example 2>

In order to remove sodium ions present in high concentrations in the effluent, first, zeolites having excellent cation exchange capacity (CEC) were purchased and used in the example experiments. The zeolite used in the experiment is a natural zeolite having a particle size of 2 mm. The zeolite was soaked in calcium regeneration solution (CaCl ₂ , 20,000 Ca ⁺⁺ mg / L) for 48 hours to replace Ca ⁺⁺ at the charged site of the zeolite. The zeolite substituted by Ca ⁺⁺ was washed three times with deionized water and used in this column experiment.

Example 3

A pilot experiment using a transparent acrylic column used to remove high concentrations of sodium ions in the effluent was carried out as follows. The acrylic column had an inner diameter of 10 cm and a height of 100 cm, and a valve was installed above and below the column, and used as an inlet and an outlet of the effluent used in the experiment. Thereafter, the zeolite substituted with charge was carefully filled with Ca ⁺⁺ prepared in Example 2.

Example 4

The effluent was collected by operating the valve at the bottom of the column at the same speed while supplying the zeolite-filled transparent acrylic column using the continuous pump at a rate of 100 ml / min.

Example 5

The distribution of E. coli group distribution, the contents of endocrine disrupting substances 1,2,4-trichlorobenzene contained in the effluent from the sewage terminal treatment plant, and the sodium ion The content change was investigated. As the experimental control, the sewage treatment plant discharged water itself was used, and the experiment was repeated three times.

The selection of endocrine disruptor 1,2,4-trichlorobenzene was selected as an indicator material based on a report by Lee Moon-Hee et al. (2005) that the detection frequency was high in sewage treatment effluent regardless of season. Tests for E. coli and sodium ions were conducted by the Water Pollution Process Test of the Ministry of Environment, and tests for 1,2,4-trichlorobenzene were carried out by gas chromatography-mass spectrometry (GC / MS) after methylene chloride extraction. Was analyzed.

The results of investigating the effect of sodium removal and reduction of E. coli and 1,2,4-trichlorobenzene according to the embodiment of the present invention compared to the discharge water directly collected from the sewage treatment plant in Jeonju-si, Jeollabuk-do are shown in Table 1 below.

[Table 1] Reduction effect of sodium, E. coli and 1,2,4-trichlorobenzene according to an embodiment of the present invention

Survey Item Sewage Treatment Plant Experiment 1 Experiment 2 Experiment 3 Sodium ions (mg / L) 134.4 9.5 10.2 8.8 Coliform group (MPN / mL) 924 0 0 0 1,2,4-trichlorobenzene (ug / L) 3.35 0.59 0.43 0.12

In Table 1, the sewage terminal treatment plant effluent refers to the effluent source itself, which has not undergone the treatment process according to the embodiment of the present invention, and Experiment 1 removes sodium by passing a gamma-irradiation dose of 1 kGy / min and a calcium-substituted zeolite column. The experiment 2 indicates that the gamma-irradiation dose 3kGy / min, the calcium-substituted zeolite column and the sodium removal process, Experiment 3 shows the gamma-irradiation dose 5kGy / min, calcium-substituted zeolite column It passes through the sodium removal process.

E. coli group of about 924MPN / mL was distributed in the sewage treatment plant effluent, but it was 100% completely sterilized when irradiated with gamma ray 1, 3, 5kGy / min. This indicates that gamma irradiation can be a very useful means to control a large number of pathogenic microorganisms distributed in sewage treatment plants.

The endocrine disruptor 1,2,4-trichlorobenzene, which is known to be contained in the effluent of the sewage treatment plant, showed 3.35 ug / L in the effluent, but 82.4% compared to the effluent when irradiated with 1kGy of gamma rays, 87.2% and 5kGy survey showed 96.4% reduction compared to discharged water. According to this embodiment, a gamma ray irradiation facility is required as a useful means for controlling the endocrine disruptor contained in the discharge water from the sewage terminal treatment plant, and 3 to 5 kGy level irradiation is required to control the residual organic pollutants. Appeared.

Finally, sodium ions contained in high concentrations in the sewage treatment plant effluent can cause phytotoxicity by itself and adversely affect soil physical properties and must be removed by appropriate treatment. As a result of the experiment, when the discharged water passed through the zeolite prepared by substituting Ca ⁺⁺ ions at the charged site, it was found to have 92.4 to 93.4% sodium removal effect compared to the sewage treatment plant effluent.

According to the present invention, when the sewage treatment plant effluent passes gamma rays emitted from the cobalt (Co-60) radioisotope, and then the effluent passes through the zeolite prepared by substituting Ca ⁺⁺ ions at the charged site, E. coli group The complete sterilization of and endocrine disrupting substances 1,2,4-trichlorobenzene 82.4 to 96.4% can be decomposed and removed, sodium ions also have the effect of removing 92.4 to 93.4%.

Therefore, by efficiently treating the effluent discharged to rivers or rivers without any treatment, it is possible to fundamentally prevent the pollution of the hydrosphere ecosystem and to secure a stable alternative water resource for agriculture.

Claims (3)

Method for producing alternative agricultural water using the discharged water discharged from the sewage terminal treatment plant, characterized in that consisting of the following steps: Irradiating 0.1 to 100 kGy of gamma rays emitted from radioisotopes to the sewage treatment plant discharged water; And Treating the effluent of the sewage terminal treatment plant for passing the sample through a zeolite prepared by substituting Ca ⁺⁺ ions at the charged site; The method of claim 1, wherein the radioactive isotope is cobalt (Co, atomic number: 60). The method of claim 1 or 2, wherein the zeolite is substituted with bentonite, the method of producing alternative agricultural water using the discharged water discharged from the sewage terminal treatment plant.

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