Monitoring Organic Loading of Onsite Wastewater Treatment Systems in the Songkhla Lake Basin

Abstract

This project aims to determine the amount of carbon and nitrogen loading of a wastewater treatment plant as a case study during (1) initial installation and (2) setup for a period of 3-5 years in the Songkhla lake basin with the flow rate measured during the day. The highest flow rate of wastewater into the plant on 0.30 and 2.30 pm at is 1 and 1.1 l/sec. and the flow rate was at its lowest during the night time. The characteristics and properties of wastewater input compared with nutrients showed the needs of the microorganisms that the ratio of BOD₅ to N (TKN) was in the range of 24.8: 5 and 32.5: 5, respectively. Those show low of carbon to nitrogen ratio and nitrogen ratio higher than BOD₅ load and the amount of wastewater in the form of TSS COD BOD₅ and TKN loading into the onsite treatment plant are 19.4 to 22.7, 10.9 to 13, 6.3 to 9.7 and from 1.7 to 2.4 kg/day, respectively. The anaerobic initial installation tank has the highest organic loading, and second was aeration initial installation tank and the anaerobic setup for 3-5 years, respectively. Finally, the overall problem for wastewater management concerns engineering and management; first, personnel who control the system is the most important by the controller not understanding about the onsite treatment system, and secondly, the cooperation from workers in the building and the monitors for the onsite treatment system.