Dongjin Lee

Effect of Volatile Fatty Acid Concentration on Anaerobic Degradation Rate from Field Anaerobic Digestion Facilities Treating Food Waste Leachate in South Korea

The purpose of this study was to investigate the effect of volatile fatty acid concentration on anaerobic degradation rate of food waste leachate in the anaerobic digestion facilities. The anaerobic digestion facilities treating food waste leachate (FWL), codigestion with food leachate and animal manure (A-MIX), and codigestion with food waste leachate and sewage sludge (S-MIX) were selected for this study. In accordance with the regulation under Wastes Control Act in South Korea, the guideline of volatile solid removal rate for anaerobic digestion facility is set as 65% for anaerobic degradation efficiency. Highest volatile solids removal rates were achieved from FWL (63.5%) than A-MIX (56.4%) and S-MIX (41.2%). Four out of eight FWLs met the guidelines. The concentration of volatile fatty acids, therefore, was analyzed to determine the relationship with volatile solid removal rate. The results showed that, in order to meet the Korean guideline of 65% volatile solid removal rate, volatile fatty acid concentrations should remain below 4,000 mg/L on the field anaerobic digestion facilities treating FWL. Volatile fatty acid concentrations should be used along with others as an operational parameter to control and manage the anaerobic digestion process.

Content characteristics of persistent organic pollutants waste from paint, iron making and steel making process

This study has been carried out in order to effectively manage three groups of unregulated hazardous organic substances (PCDD/DFs, PAHs, PCBs) in South Korea. The investigated substances have been analyzed according to the test methods for hazardous substances in specified wastes provided by the National Institute of Environmental Research, Korea. Total contents of the organic compounds have been determined for hazardous wastes from three major industrial categories (paint, iron removal, steelmaking), such as waste organic solvent, waste paint or dust. By investigating the waste samples for 7 PAHs using GC/MSD, Naphthalene has been detected (N.D~1631.33 mg/kg). The highest Naphthalene concentration, which exceeded the korean marine dumping waste standard, was found in waste organic solvents and waste paints. Although a content analysis of 7 PCB isomers has been conducted, none of these compounds was detected. The analysis of PCDD/DFs has revealed that all samples meet the criterion for low POP content defined in the technical guidelines developed under the Basel Convention. The PCDD/DFs content in dust samples deriving from 10 manufacturing processes (billet, bloom) was determined to be in the range of N.D~5.66 ng I-TEQ/g waste.

Characteristic of Nutrient Release by Submerged Plants under Different Water Temperatures in Lake Reservoir

To evaluate effects of water temperatures on nutrient releases of submerged plants in lake reservoir, COD, T-N and T-P releases of submerged plants were investigated for 60 days under different incubation temperatures ( and ) in columns. The amounts of COD releases by Carex dimorpholepis were at and at . In Miscanthus sacchariflorus, the amounts of COD releases were at and at . The amounts of T-N releases in Carex dimorpholepis at and were 45.8 and , respectively. In Miscanthus sacchariflorus, the amounts of T-N releases were at and at . At , the amounts of T-P releases in Carex dimorpholepis and Miscanthus sacchariflorus were 5.65 and , respectively. At , the amounts of T-P releases in Carex dimorpholepis and Miscanthus sacchariflorus were 8.70 and , respectively. In the column experiment, the amounts of COD, T-N and T-P releases by submerged plants at were generally higher than those at .

Growth Characteristic and Nutrient Uptake of Water Plants in Constructed Wetlands for Treating Livestock Wastewater

BACKGROUND: Constructed wetlands for wastewater treatment are vegetated by wetland plants. Wetland plants are an important component of wetlands, and the plants have several roles in relation to the livestock wastewater treatment processes. The objectives of this study were to investigate the growth characteristics and nutrient absorption of water plants in constructed wetlands for treating livestock wastewater. METHODS AND RESULTS: In this study, livestock wastewater treatment plant by constructed wetlands consisted of water plant filtration bed, activated sludge bed, vertical flow(VF), horizontal flow(HF) and HF beds. Phragmites communis TRINIUS(PHRCO) was transplanted in VF bed, Iris pseudoacorus L(IRIPS) was transplanted in HF bed and PHRCO, IRIPS and Typha orientalis PRESEL(THYOR) were transplanted in HF. Growth of water plants in constructed wetlands were the highest in October. The IRIPS growth was higher than other plant as 264 g/plant in October. The absorption of nitrogen and phosphorus by IRIS were 3.38 g/plant and 0.634 g/plant, respectively. The absorption of K, Ca, Mg, Na, Fe, Mn, Cu and Zn by water plants were higher in the order of IRIPS > THYOR > PHRCO. CONCLUSION(S): The absorption of nutrients by water plants were higher on the order of IRIPS > THYOR > PHRCO in constructed wetlands for treating livestock wastewater.