This study is to manufacture a titanium dioxide (TiO2) photocatalyst by recycling sludge generated using titanium tetrachloride (TiCl4) as a coagulant. Compared to general sewage, a TiCl4 coagulant was applied to dyeing wastewater containing a large amount of non-degradable organic compounds to evaluate its performance. Then the generated sludge was dried and fired to prepare a photocatalyst (TFS). Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), and nitrogen oxide reduction experiments were conducted to analyze the surface properties and evaluate the photoactive ability of the prepared TFS. After using titanium tetrachloride (TiCl4) as a coagulant in the dyeing wastewater, the water quality characteristics were measured at 84 mg/L of chemical oxygen demand (COD), 10 mg/L of T-N, and 0.9 mg/L of T-P to satisfy the discharge water quality standards. The surface properties of the TFS were investigated and the anatase crystal structure was observed. It was confirmed that the ratio of Ti and O, the main components of TiO2, accounted for more than 90 %. As a result of the nitric oxide (NO) reduction experiment, 1.56 uMol of NO was reduced to confirm a removal rate of 20.60 %. This is judged to be a photocatalytic performance similar to that of the existing P-25. Therefore, by applying TiCl4 to the dyeing wastewater, it is possible to solve the problems of the existing coagulant and to reduce the amount of carbon dioxide generated, using an eco-friendly sludge treatment method. In addition, it is believed that environmental and economic advantages can be obtained by manufacturing TiO2 at an eco-friendly and lower cost than before.

The purpose of this study is to produce the auxiliary fuel additives that will improve the heat value and reduce the odor of dried sewage sludge, an auxiliary fuel for power plants using process by-products. Through an odor analysis prior to the production of auxiliary fuel additives, it was confirmed that the main odor materials are Methylmercaptan, Acetaldehyde and Trimethylamine. Based on this, we measured the heating value on various processes by-products such as by-products of thermal power generation and by-products of refinery. In addition, the adsorption performance in the major odor material was evaluated. However, for Trimethylamine, it is very difficult to secure the reproducibility of the concentration of the standard materials as the standard material is liquid. Therefore, it was used Ammonia, which has basic property, to replace Trimethyamine. In the evaluation of various process by-products, the highest heating value in heavy oil fly ash was 5,575 kcal/kg, while in the adsorption performance evaluation, FCC was shown as having the best performance in adsorption, as it could adsorb 100% of Methylmercaptan, 47% of Acetaldehyde and 76% of Ammonia. We conducted an adsorption experiment after supporting a transition metal on the FCC in order to improve the adsorption capacity. As a result, it was confirmed the best efficiency when supporting the copper nitrate 0.5% on the FCC. Based on this result, the experiment was conducted to determine the optimal mixing ratio with a high heating value and odor reducing function using Heavy oil fly ash and FCC. The optimal mixing ratio was 90% of Heavy oil fly ash and 10% of FCC. Furthermore, it was found that the most economical performance and highest odor reducing efficiency was achieved when the mixing ratio was 90% of dried sewage sludge and 10% of auxiliary fuel additives.

The performance of the new aerobic digestion system combined with inorganic sludge separation unit and sludge solubilization unit, CaviTec II, is evaluated. Anaerobic digester effluent sludge is used for feed sludge of CaviTec II system. By addition of CaviTec II, the amount of cake generated is reduced by 27%, and the soluble nitrogen is reduced by 92%.

It is essential to decrease energy consumption and excess sludge to economically operate sewage treatment plant. This becomes more important along with a ban on sea dumping and exhaustion of resource. Therefore, many researchers have been study on energy consumption reduction and strategies for minimization of excess sludge production from the activated sludge process. The aeration cost account for a high proportion of maintenance cost because sufficient air is necessary to keep nitrifying bacteria activity of which the oxygen affinity is inferior to that of heterotrophic bacteria. Also, additional costs are incurred to stabilize excess sludge and decrease the volume of sludge. There were anoxic, aerobic, membrane, deairation and concentration zone in this MBR process. Continuous aeration was provided to prevent membrane fouling in membrane zone and intermittent aeration was provided in aerobic zone through ammonia sensor. So, there was the minimum oxygen to remove NH4-N below limited quantity that could be eliminated in membrane zone. As the result of this control, energy consumption of aeration system declined by between 10.4 % and 19.1 %. Besides, we could maintain high MLSS concentration in concentration zone and this induced the microorganisms to be in starved condition. Consequentially, the amount of excess sludge decrease by about 15 %.

본 연구는 원유로부터 정제된 파라자일렌(Para Xylene)을 원료로 테레프탈산(TPA: Terephthalic acid)을 생산하는 공정에서 배출되는 저순도 테레프탈산 잔사인 CTA(Crude Terephthalic acid)의 악취저감을 위한 저감제 개발과 유기성슬러지의 고형연료 활용 방안에 관하여 연구하였다. TPA 석유화학 공정에서 발생되는 TPA 슬러지의 발생량은 0.3~0.4%/kg이며, 슬러지는 보관 또는 운송, 소각 과정에서 끊임없이 악취를 발생시키며 대기환경에도 많은 영향을 끼친다. 이러한 악취로 인해 고효율의 열량을 가졌음에도 화력발전소의 연료로 이용하지 못하고 있는 실정이다. 악취저감제는 탄소수가 많은 고지방산과 비이온계면활성제 등을 일정 조성비로 혼합하여 실험하였고, fatty acid 15~30, mono fatty acid 20~35, linolenic acid 20~35, oleic acid 20~25, palmitic acid 5~10, non0ionic surface active agent 5~7% 구성성분 조성비를 갖는다. TPA 유기성 슬러지를 고형연료로 활용하기 위해 고형연료 품질시험에 따른 전 망목에 대해 실험하였다. 고형연료 샘플 500g을 기준으로 TPA 슬러지와 TPA 슬러지에 애쉬 10%를 첨가한 시료 각 두 종류에 대하여 실험한 결과 저위발열량 기준 3,960과 3,540 kcal/kg으로 각각 나타나 고형연료제품 품질기준 3,500 kcal/kg 이상을 만족하여 활용가치가 높은 것으로 나타났다. 또한 염소 0.03%, 황분･수은･카드늄･납･비소･안티몬 불검출, 크롬 45.4mg/kg, 코발트 5,400 mg/kg, 구리 145 mg/kg, 망간 1,300 mg/kg, 니켈 44.4 mg/kg, 탈륨･바나듐 불검출로 나타났다. 악취저감을 위한 pilot-plant는 그림 1과 같이 구성하여 실험하였고, 악취저감제는 0~25% 슬러지 중량비로 주입하여 처리특성을 조사였다.

In this study, GC-MS linked with an automatic thermal desorber was used to quantitatively analyze the odorous and volatile compounds in the gas emitted from a sewage sludge drying facility. In addition, the removal characteristics of these compounds were investigated by using a pilot-scale packed bed wet scrubber. A quantitative analysis for 58 odorous and volatile compounds in the gas was successfully achieved with GC-MS and GC-FPD. The a quantitative analysis revealed the major odorous compounds were hydrogen sulfide and acetaldehyde. In addition, D-type siloxane compounds such as octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6), were quantitatively measured. The concentrations of siloxane compounds measured in the gas were in the range of 4.54- 7.36 ppmv, higher than those in landfill gas. The average removal efficiency of the odorous and volatile compounds in a wet scrubber was 67.37%. D4, D5, and D6, which are hydrophobic compounds, were also removed by as much as 50.68%, 44.56%, and 70.26%, respectively.

This research intends to develop a photocatalytic concrete enabling to decompose the nitrogen oxides (NOx) using a titanium oxide photocatalyst for reducing the cost. In details, this research develops the mix composition of the photocatalytic concrete exhibiting photolytic characteristics and establish the technology enabling to reduce the emission of air pollutant caused by nitrogen oxides.