Excess nitrogen (N) flowing from livestock manure to water systems poses a serious threat to the natural environment. Thus, livestock wastewater management has recently drawn attention to this related field. This study first attempted to obtain the optimal conditions for the further volatilization of NH3 gas generated from pig wastewater by adjusting the amount of injected magnesia (MgO). At 0.8 wt.% of MgO (by pig wastewater weight), the volatility rate of NH3 increased to 75.5% after a day of aeration compared to untreated samples (pig wastewater itself). This phenomenon was attributed to increases in the pH of pig wastewater as MgO dissolved in it, increasing the volatilization efficiency of NH3. The initial pH of pig wastewater was 8.4, and the pH was 9.2 when MgO was added up to 0.8 wt.%. Second, the residual ammonia nitrogen (NH4 +-N) in pig wastewater was removed by precipitation in the form of struvite (NH4MgPO4·6H2O) by adjusting the pH after adding MgO and H3PO4. Struvite produced in the pig wastewater was identified by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis. White precipitates began to form at pH 6, and the higher the pH, the lower the concentration of NH4 +-N in pig wastewater. Of the total 86.1% of NH4 +-N removed, 62.4% was achieved at pH 6, which was the highest removal rate. Furthermore, how struvite changes with pH was investigated. Under conditions of pH 11 or higher, the synthesized struvite was completely decomposed. The yield of struvite in the precipitate was determined to be between 68% and 84% through a variety of analyses.

This paper presents the applicability of natural zeolite (Clinoptilolite) for recovery of ammonium nitrogen from high-strength wastewater stream. Isotherm experiments showed the ammonium exchange Clinoptilolite followed Freundlich isotherm and its maximum exchange capacity was 18.13 mg NH4+-N/g zeolite. The X-ray photoelectron spectroscopy (XPS) analysis indicated that a significant amount of nitrogen was adsorbed to the Clinoptilolite. Optimal flowrate for recovery of high concentration ammonium nitrogen was determined at 16 BV/d (=19.2 L/min) throughout the lab-scale column studies operated under various flowrate conditions. This study also provided a method to determine the recovery rate of final product of nitrogen fertilizer based on the model application to the lab-scale continuous data.

본 연구는 제품 생산과정 시 해충혼입에 의한 소비자 해충 클레임 발생 가능성을 규명하고자 고농도 질소충진(98.6~98.8%) 유아용 캔 포장 분유제품에서의 화랑곡나방 알, 유충(4령)의 발육 가능성을 알아보았다. 고농도 질소가스와 일반 대기로 포장된 제품내부에서 보관기간에 따라 부화율, 우화율, 치사율 등을 조사하였고 포장해체 후 지속적으로 보관하면서 동일한 조사를 수행하였다. 실험 결과 질소충진 처리하였을 경우 보관기간에 관계없이 화랑곡나방 알과 유충은 100% 치사하였다. 그러나 질소가 충진되지 않은 처리구에서 유충 치사율은 대략 40%정도를 나타내었고, 보관 기간에 따라 유의한 차이는 보이지 않았다(df=2,27, F=2.06, P>0.05). 화랑곡나방 알의 경우 모든 반복에서 실크가 발견되어 부화가 이루어졌으나, 발육이 지속적으로 진행되었을 경우 발견되었을 것으로 예상되는 2~3령 유충이 발견되지 않아 분유제품이 갓 부화한 1령 유충의 먹이로는 적합하지 않은 것으로 조사되었다.

The purpose of this research was to investigate applicative possibility of field. Pilot-scale experiments were conducted, at outdoor temperature, HRT 10hour, IR(Internal Recycle) 150% and used 2.8㎥ Reactor. External carbon source was varied 80 to 120 mg/L. When External carbon source and Alkalinity were injected to the B3 pilot plant, the removal efficiencies of COD and BOD were not decreased. Nitrification rate were 5.95, 5.40, 4.08 mgNH4+-N/gSS/d during operation periods and denitrification rate was 3.12mgNO3--N/gSS/d. When we surveyed the relationship between loading rate of nitrogen and nitrogen removal quantity, this data was 0.949, B3 process will be possible application process of field.