코크스폐수는 페놀, 암모니아, 황화시안, 시안화합물과 같은 오염물질들을 고농도로 함유하고 있는 유독성 산업폐수이다. 국내에서는 이 폐수를 처리하기 위해 생물학적 전탈질공정(biological pre-denitrification process)을 주로 사용하고 있다. 그러나 원인을 알 수 없는 이유로 질소제거효율이 급격히 떨어지는 문제가 발생하고 있으며, 여름철에 더 실공정이 불안정해진다. 따라서 이번 연구에서는 코크스폐수가 가장 먼저 유입되는 탈질조를 대상으로 폐수에 함유된 페놀, 암모니아, 황화시안, 철-시안, 프리시안이 온도변화에(20~38 ℃)에 따라 탈질조 슬러지에 어떠한 영향을 미치는지 회분식 탈질실험을 통해 살펴 보았다. 그 결과 탈질반응은 여름철 실 공정의 운전온도(38 ℃)에서 최적을 보였으며, 오_x000D_ 염물질들의 분해속도도 온도가 증가할수록 빨라졌다. 페놀, 암모니아, 황화시안, 철-시안은 200 mg/L 이하의 농도에서는 탈질반응에 거의 영향을 주지 않았으나, 프리시안은 0.5 mg/L의 저농도에서도 탈질반응에 심각한 저해를 주었다. 한편, 오염물질의 독성효과는 온도가 증가할수록 감소하는 현상을 보였다.

Cokes wastewater is one of the most toxic industrial effluents since it contains high concentrations of pollutants, such as phenol, ammonia, thiocyanate and cyanides. Although biological pre-denitrification process has been used to treat this wastewater in Korea, unexpected failure in nitrogen removal occasionally occurs during summer season. In this study, therefore, we examined inhibitory effects of phenol, ammonia, thiocyanate, ferric cyanide and free cyanide on biological denitrification according to temperature variation (20~38 ℃). Batch experiments showed that denitrification rate was faster in summer (38 ℃) than other seasons, and removal rates of pollutants increased with increasing temperature. Phenol, ammonia, thiocyanate and ferric cyanide did not inhibit denitrification even at its high concentration (200 mg/L). However free cyanide above 0.5 mg/L seriously inhibited the bilolgical denitrification reaction. Inhibitory effect of these pollutants was reduced with increasing temperature.

Cokes Wastewater Denitrification Pre-denitrification Process Phenol Thiocyanate Cyanides

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