Immobilization of anaerobic ammonium oxidizing bacteria has been studied to enhance the biomass retention of the slowly growing bacteria and the process stability. The purpose of this study was to compare the nitrogen removal efficiency of granular and immobilized anammox bacteria with poly vinyl alcohol and alginate. The specific anammox activity of the granular, homoginized and immobilized anammox bacteria were 0.016±0.0002 gN/gVSS/d, 0.011±0.001 gN/gVSS/d and 0.007±0.0005 gN/gVSS/d, respectively. Although the activity decreased to 43.7 % of the original one due to low pH and O2 exposure during the homogination and the immobilization, it was rapidly recovered within 7 days in the following continuous culture. When synthetic T-N concentrations of 100, 200, 400, 800 mg/L were fed, the immobilized anammox bacteria showed higher nitrogen removal efficiencies at all operational conditions than those of granular anammox bacteria. When the sludge retention time was shorten below 30.7 days and the reject water was fed, the nitrite removal efficiency of the granular anammox bacteria dropped to 8 % of the initial value, while that of the immobilized anammox bacteria was maintained over 95 % of the initial one. The immobilization with poly vinyl alcohol and alginate would be a feasible method to improve the performance and stability of the anammox process.

This study investigated the feasibility of odor removal using ultrasonic droplets of electrolyzed water. 91.65% of the injected electrons were converted to oxidizing agents including hypochlorous acid at HCl 2.2%, 3 V, and a retention time of 5 min. The size of the droplets generated by the ultrasound showed a distribution with D25=1.359 μm and D75=2.506 μm. The odor removal efficiency of the electrolyzed water droplets was over 90% for a composite odor composed of acetaldehyde, hydrogen sulfide, and ammonia, while that of tap water droplets was 50%. The electrolyzed water droplets were also effective in removing ammonia generated in full-scale organic waste treatment facilities.

This work aimed to analyze current status of by-products generation and industrial symbiosis network in Gyeongsangbuk-do, South Korea. Manufacturing sector of the province mainly consists of electronics, machinery, steel, metal-working industries. Gumi and Pohang have the 1st and 2nd largest worker population in the manufacturing sector. 21,950.7 ton/d of waste is generated from the industries in 2011, of which 82.2% is recycled. The industrial waste, which is not recycled, is mainly composed of sludge cake from domestic wastewater treatment plants, waste plastic, incinerator ash, and slag. Pohang is the largest generating city of both total and the non-recycled industrial waste in the province, and most of the waste is from Pohang steel industrial park. Symbiosis map in Pohang steel industrial park shows that most of the current material symbiosis in the industrial park is for waste refractories and slag.