電子酸化工程을 利用한 畜産廢水處理에 관한 硏究

Abstract

The test of the single cathode discharge structure or high-voltage pulse corona electron generating device as batch-type one, the test combining the electron generating device with the electromagnetic wave generating device, the continuous test of pilot plant operation obtained the following results. 1. Batch-type single cathode discharge structure electron generating device test 1) As for disintegration of phenol depending on the number of single cathode discharge structure electron generating devices, the more devices, the higher removal efficiency. Major mechanisms of the disintegration included oxidation caused by ozones and OH radicals generated by high-voltage discharge in the atmosphere and reduction decomposition of hydrated electrons. 2. Batch-type high-voltage pulse corona electron generating device test 1) Distilled water and the aqueous solution of phenol decreased in pH from 8.46 to 6.40 and from 7.97 to 3.90, respectively. The decrease of pH in distilled water resulted from generation of hydrogen peroxide; it is assumed that the remarkable decrease of pH in the aqueous solution of phenol was influenced by organic acids as oxidation by-products of phenol, including muconic acids and o-benzoquinone. 2) By-products of the aqueous solution of phenol contained 29.24min O-Benzoquinone and 63.44min muconic acids. Since these are identical to oxidation intermediates of phenol, which were generated during the advanced oxidation process based on ultrasonic waves, it was predicted that main oxidizing agents leading disintegration of phenol through the discharge of high-voltage pulse corona were OH radicals. 3) The disintegration test in the aqueous solution of phenol demonstrated that removal efficiency was 3 times higher with both air and excitation electrons injected than with only air injected. This is because 5ppm ozones, 28,883,400ion hydrated electrons, and OH radicals generated from the electron generating device using the discharge of high-voltage pulse corona are involved in phenol removal. 4) As for the removal rate by initial concentration of the aqueous solution of phenol, the higher initial concentration, the higher reaction efficiency, probably because a great amount of excitation (hydrated) electrons, ozones, and OH radicals generated from the electron generating device more frequently get contact with the high-concentration aqueous solution of phenol. 5) Of 77% removal efficiency, OH radicals (40%) made the greatest contribution to the removal rate, followed by oxidation power caused by ozones (20%) and hydrated electrons (12%). The remaining 5 percent might be explained by the effects of thermal energy resulting from reactions among radicals (H·, O·, HO2, O2-·) generated during the discharge of high-voltage corona. 3. Batch-type electron generating device and electromagnetic wave device combination test 1) Both synthetic and swine samples showed a gently rising curve for the value of conductivity because ionic compounds are created during the process of generating various ionic matters through the discharge of high-voltage pulse corona and decomposing high-concentration organic matters. 2) It took one or two days to decompose synthetic wastewater composed of COD 60ppm; the removal rate for 60ℓ, 80ℓ, and 100ℓ swine samples was 72.8 percent, 48.8 percent, and 44.6 percent, respectively. 3) The T-N removal rate for synthetic wastewater was 24.7 percent while the removal rate for 60ℓ to 100ℓ swine samples all was 10 to 12 percent. This is because ammonia nitrogen was directly stripped due to air supplied in 35L/min and to the wastewater temperature of 28℃ to 30℃ and because ammonia was changed into N2 through reaction with OH radicals and stripped into the atmosphere. 4) The T-P removal rate for synthetic wastewater was 3.3 percent while the removal rate for 60ℓ to 100ℓ swine samples all was 2.5 to 2.9 precent. The removal rate of a little phosphorus from a swine sample can be explained by generation of insoluble deposits through reaction between phosphorus and calcium as solid matter depending on swine alkalinity. 4. Continuous pilot plant test The average concentration of swine wastewater used to operate pilot plant was 10,971ppm for TBOD, 4,486ppm for CODMn, 7,540ppm for SS, 2,432ppm for T-N, and 242ppm for T-P; on these conditions, it was operated through the electron oxidation process, consequently obtaining the following results. The removal efficiency for BOD, COD, SS, T-N, and T-P all was over 95 percent; the average removal rate for BOD (82.1%) was highest, followed by COD (44.3%), T-N (37.3%), and T-P (30.1%), with SS increased by 4.8 percent as compared with raw water concentration. The removal rate for T-N was 59.9 percent in the primary sediment, 68.3 percent in an activation tank, and 84.35 percent in the secondary sediment.