A Study on the change of nitrogen removal characteristics in the applications of external carbon sources using organic waste resources

Abstract

Waste water emitted from industrial facilities is increasing in relative inorganic content along with a decrease in the amount of organic matter every year, making it difficult to remove nutrients caused by high concentrations of organic matter in the early stages of wastewater treatment. In the wastewater treatment process, the denitrification process for nitrogen removal requires organic carbon as an electronic donor, so the addition of external carbon sources is necessary, but there is a concern of increased cost, obstruction of nitrification of residual organic carbon sources. The external carbon sources used for denitrification can include methanol, ethanol, and wastewater, which have been studied in various ways. However, failure to properly use these sources of external carbon can lead to a decrease in denitrification efficiency, which can lead to increased COD(Chemical Oxygen Demand), resulting in deterioration of water quality as well as a decrease in nitric oxide efficiency. Therefore, the purpose of this study was to investigate the nitrogen removal characteristics of wastewater when applying wastewater, methanol, and antibiotic-announced wastewater used as an external carbon source. This study was conducted in a biological diffuse reaction tank, and the KNO3 reagent was injected to 1.4 mg/L within the reaction tank to see the denitrification efficiency, and methanol, A negative wastewater, B negative waste water, and antibiotic fermented waste were injected in the same amount. Methanol, primary treated water, and antibiotic fermented waste reduced the total solids concentration of sludge in bioreactors by 5.2%, 17.4% and 3.4%, respectively, but the total solids concentration of A food wastewater and H food wastewater was increased by 9.1% and 8.3%, respectively. In addition, the concentration of T-N(Total Nitrogen) in bio-reactor treated water decreased by 15.6% and 0.97% and 0.85%, respectively, when methanol, primary treatment water and antibiotic fermented waste liquid were injected, but T-N in A food wastewater and H food wastewater negative waste water increased by 6.7% and 2.9%, respectively. The concentration of NO3--N in methanol, primary treated water, antibiotic fermented waste solution, A negative wastewater, and H negative wastewater was reduced by 56.4%, 9.95%, 0.85%, 11.8% and 18.3%, respectively. If organic waste resources are applied as external carbon sources in the wastewater treatment process, it is possible to supply insufficient carbon sources during the denitrification process, but the nitrogen concentration of organic waste resources can rather increase the concentration of T-N. Further research on the possibility of decomposition of nitrogen sources contained in drinking water and antibiotic fermented waste liquid in the wastewater treatment process will be conducted through continuous experiments by type of organic waste resources.