초음파와 스코리아를 이용한 골프장 저류지의 조류제거

Abstract

The specimen was taken from the pond artificially created at the golf course, the algae was controlled as move and fix, and the specimen was periodically taken over 2 months, and the concentration of Chlorophyll-a was analyzed. And based on the concentration result of Chlorophyll-a, the optimal conditions of algae removal using ultrasound through the power, frequency and ON/OFF test of the ultrasound were elicited. And to maximize the effectiveness of algae removal using ultrasound, the experiment was performed by adding dusting powder, which was scoria as environment-friendly natural material, widely distributed throughout Jeju-do, targeted for extracting the proper condition of scoria and ultrasound appliable to the field, and reaching the following findings. 1) The observation of Algae showed that Aug. 23 through Sept. 10, dominant species is Cyanobacteria containing toxic materials, Anabaena spiroides, and Chlorophyll-a is 106.82㎍/ℓ～549.90㎍/ℓ. Staring from Sept. 14, Microcystis areuginosa is dominant species, and the concentration is 61.17㎍/ℓ～1628.84㎍/ℓ. It is higher than Chlorophyll-a concentration in other lakes or reservoirs about 10～40 times. 2) The comparative experiment of ultrasound frequency(40kHz, 28kHz) and power(40W, 80W, 120W) showed that the frequency is low as the finding of existing studies, and with power in high condition, the removal efficacy of Chlorophyll-a was high. But in case of high-concentration Chlorophyll-a, it sustained a constant value without any change 30 minutes after exposure in spite of high power, 120W. 3) The ON/OF experiment of ultrasound with power at 28kHz, 120W and exposure time between 30～120 minutes to explore the effect of ON/OFF during the exposure time of the ultrasound generator on the removal efficacy of algae showed that the removal efficacy was kept regardless of ON/OFF time. It can save 30-minute power and periodical exposure of ultrasound contributes to removal efficacy. 4) With jar-tester stirred for about 30 minutes at 200rpm, and precipitation time at 30min, 60min, 90min, 120min, the maximum removal efficacy of Scoria was 49% at 2g/ℓ after 90 minutes, and the optimal condition was 125㎛, 2g/ℓ. 5)The removal efficacy at concentration was 84%～93% at 30 minute exposure time of ultrasound using the optimal condition of ultrasound 28kHz, 120W, and that of Scoria, 125㎛, 2g/ℓ. And the removal efficacy of Chlorophyll-a at exposure time of 120 minutes showed the value of 99% or more, which indicated the largest removal efficacy.