| Summary: | 碩士 === 國立屏東科技大學 === 畜產系 === 91 === Abstract
The number of pigs growing in Taiwan area is increasing year by year. In 1997 the density of pig population is 221 heads / SqKM. In 1998, the Government established strict standard for waste water discharge of animal farm on biological oxygen demand (BOD), Suspension Solid (SS) and Chemical Oxygen Demand (COD). And the control over the conductivity of waste water discharge will soon be imposed. Further studies are planned for reducing the salt content, heavy metal additive and the effect of silt generated from the waster water treatment to the conductivity of waste water discharge, so as to design dilution methods for reducing the conductivity of the waste water discharge. The study is separated in 5 trial. Trial 1: Sampling from reservoir, river, underground water and pig farm waste water to test for various data, including conductivity and pH. Trial 2: 24 heads of 28 day age LYD crossbred weanling pigs are distributed randomly into 3 groups with 3 different feeds of 0%, 0.2% and 0.4% salt contents. The young pigs are bred in an environment weather room in free feeding manner for 8 weeks. The residues are cleaned out to weigh to measure the intake quantities. 20 LYD crossbred female pigs in the average weight of 58 kgs are distributed randomly into 5 groups with feed salt content of 0%, 0.1%, 0.2%, 0.3% and 0.4%. The pigs are raised on metabolism cage in an environment temperature control room. After 7 days adaptation period, then formally conduct metabolism measuring for 8 days. The excrement and urine are collected on the 4th and 8th days are collected to measure the conductivity. Trial 3 test is conducted on 12 LYD crossbred female pigs in the average weight of 38kgs and randomly distributed into 3 groups of feeds with contents of copper and zinc respectively 50ppm/ 94ppm, 50ppm / 30000ppm and 250ppm / 94ppm. The pigs are raised on a metabolic rack in environment weather rooms. After 7 days orientation period, the metabolism examination is conducted for 8 days and the excrement and urine are collected on 4th and 8th days to measure the conductivity. Trial 4 test is conducted by sampling from aeration pit of the school farm at fixed time on daily basis. The samples collected are taken to measure the conductivities and pH value. Trial 5 test is conducted on the discharge water from the 3-Step pig manure waste water treatment process, anaerobic fermentation and aerobic fermentation and the top clear liquid of continuous batch aeration pit, diluted with tap-water in the ration of 1:1 and measure the conductivities of the waster water prior to dilution, tap-water and those after dilution.
Results of trial 1 test indicates that the discharged waste water of excrement and urine of pig after treatment of waste water treatment system has still a conductivity as high as 3490μs/cm, and those fed with food residue are even as high as 7840μs/cm. Certain areas with underground water conductivity higher than 1000μs/cm. When such water is used to rinse piggery, it will result in the increase of conductivity of waste water.
The results of trial 2 and trial 3 tests show that the conductivity of pig excrement and urine tends to increase following the addition of salt, copper and zinc additive. The result of trial 4 test shows the conductivity of waste water tends to increase following the accumulation of silt. The result of trial 5 test shows the diluted waste water has 60% conductivity of the original.
Concluding the results of trial 1 through trial 5 tests, the 0.2% feed salt addition is more suitable. The addition of copper and zinc is better be as established by the government and remove the excessive silt in the waste water on daily basis, which will help to reduce the conductivity of discharged waste water. Dilution can reduce the conductivity of discharged waste water, however, when the conductivity of the water used in dilution is exceeding 750μs/cm, it would not be able to reduce the conductivity of the waste water discharged.
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