• Environmental Engineering Research
• /
• v.20 no.1
• /
• pp.79-87
• /
• 2015

To treat leather industry wastewater (LIW) containing high nitrogen concentration, eight aerobic denitrifiers were isolated from sludge existing in an LIW-treatment aeration tank. Among them, one strain named as KH8 had showed the great ability in denitrification under an aerobic condition, and it was identified as Pseudomonas aeruginosa R12. The aerobic denitrification ability of the strain KH8 was almost comparable to its anaerobic denitrification ability. In lab-scale aerobic denitrifications performed in 1-L five-neck flasks for 48 hr, denitrification efficiency was found to be much improved as the strain KH8 held a great majority in the seeded cells. From the nitrogen balance at the cell-combination ratio of 10:1 (the strain KH8 to the other seven isolates) within the seeded cells, the percentage of nitrogen loss during the aerobic denitrification process was estimated to be 58.4, which was presumed to be converted to $N_2$ gas. When these seeded cells with lactose were applied to plant-scale aeration tank for 56 day to treat high-strength nitrogen in LIW, the removal efficiencies of $COD_{Cr}$ and TN were achieved to be 97.0% and 89.8%, respectively. Under this treatment, the final water quality of the effluent leaving the treatment plant was good enough to meet the water-quality standards. Consequently, the isolated aerobic denitrifiers could be suitable for the additional requirement of nitrogen removal in a limited aeration-tank capacity. To the best of our knowledge, this is the first report of aerobic denitrifiers applied to plant-scale LIW treatment.

• Journal of Korean Society on Water Environment
• /
• v.29 no.5
• /
• pp.656-665
• /
• 2013

This research was conducted to investigate pollutant load unit factor from aquacultural farms. Pollutant load unit factors were investigated on the 13 kinds of fish type, i.e., Trout, Leather Carp, Eel, Carp, Cartfish, Freshwater Eel, Crucian Carp, Colored Carp, Sturgeon, Marsh Snail, Sweetfish, Pond Snail, Eriocheir Sinensis. Water qualities in aquacultural farms were investigated wide range of values by fish type and pollutant items. High BOD and COD values were observed at the Leather Carp (Ponded water system), Cartfish (Ponded water system) and Freshwater Eel (Recirculating System). TOC and DOC values were relatively high at the Freshwater Eel (Recirculating System) and Eriocheir Sinensis (Extensive). Eel (Ponded water system) and Freshwater Eel (Recirculating System) produced high concentrated nutrient pollutants, i.e., T-N, T-P. Pollutant load unit factors are dependent on fish type, aquacultural type, water quality items, etc. If some fishes have similar basic unit values, those could be applied for TMDLs as a group of fish having same pollutant load unit. The water quality concentrations of post treatment facilities' (mainly reservoir tank) effluent were higher than those of fish raising bath because of extracting pollutant from sediment in the reservoir tank. Therefore, it needs to the management and regulations about post treatment facilities.

• Journal of Korean Society on Water Environment
• /
• v.22 no.1
• /
• pp.37-44
• /
• 2006

Ecotoxicity assessments of 90 selected effluents of 22 industry types from 2002 to 2004 in Korea were evaluated by a toxic battery of bioassay test using fish Oryzias latipes, invertebrate Daphnia magna, algae Selenastrum capricornutum and bacteria Vibrio fischeri with the physicochemical measurement items and permit concentrations on the present Water Quality Conservation Act in Korea. Total toxic unit (${\Sigma}TU$) of 8 industry types of 22 industry types by the toxic battery appeared in order of the value site as follows; Pigment Dye Manufacturing (${\Sigma}TU$ 217.1) > Textile and Dye (${\Sigma}TU$ 39.3) > Semiconductor Electronic Manufacturing (Small) (${\Sigma}TU$ 25.6) > Wastewater and Sewage Treatment Plants (${\Sigma}TU$ 25.4) > Coating (${\Sigma}TU$ 23.8) > Leather Skin Manufacturing (${\Sigma}TU$ 18.0) > Synthetic Resin Manufacturing (${\Sigma}TU$ 15.6) > Assemble Metal Manufacturing (${\Sigma}TU$ 10.7). Our results demonstrate that ecotoxicity assessment, by bioassay test, is effective and practical for industrial wastewater management for 90 selected effluents with the limitation of the physicochemical permit. Among 90 effluents, 9 samples failed physicochemical permit limitation and 81 passed it. In result of ecotoxicity assessment of 90 effluents by the toxic battery, 76 effluents exhibited ecotoxicity and the others did not. The physicochemical measurement items and permit concentrations on the present Water Quality Conservation Act in Korea were low related to the ecotoxicity value by the toxic battery and appeared limited for water quality management to water-ecosystem and environment-friendly management of water.