Papers by Author: Hyun Jong Joo

Abstract: The aim of this research was to develop a zeolite carrier for wastewater treatment in a small-size sewage treatment facility. To evaluate the ion-exchange characteristic of zeolite medium, the isotherm equation of both Langmuir and Freundlich model were examined. It was found that the maximum absorption amount (q_m) and adsorption strength (1/n) were about 2.94 mg NH₄⁺-N/g and 0.3854, respectively. In order to validate the adsorption performance by applying the zeolite carrier to the in-situ field, nitrogen removal efficiency was evaluated by a retrofitted process in the small sewage treatment where carbon-nitrogen ratio was especially low in influent. By the application of this proposed method, the effluent TN concentration was in the range of 6.5-20 mg/L (average of 12.9 mg/L) which may satisfy sufficient discharge standard limit. The zeolite medium had ion-exchange capacity of 30-40% of influent NH₄⁺-N concentration, and TN removal efficiency improved about 40% compared to the existing process. Therefore, the renovation of the carrier utilization shows the possibility of pre-treatment of NH₄⁺-N in influent and thus improves the TN removal efficiency of wastewater treatment.

Abstract: The dependence of composition and sintering temperature on physical properties of ALA was investigated. Mechanism of black discoloration(sometimes called black core) usually found in the interior cores of artificial lightweight aggregate was also investigated by the optical observations. As a result, the primary cause of black discoloration in the interior of the lightweight aggregate body resulting from incomplete burn-out of carbonaceous impurities and iron-containing materials.In the cross-sectional morphology of ALA, bloating phenomena as well as formation of large pores were found in the samples containing ferrous materials. By increasing content of ferrous materials, both specific gravity and water absorption have been decreased.