REAL-TIME BOD MONITORING FOR WASTE-WATER PROCESS-CONTROL

This is a preliminary investigation of a method for the timely monitor ing of wastewater biochemical oxygen demand (BOD). Many ecological and economic pressures support the use of BOD measurement methods fast en ough to prevent process upsets. Since the standard laboratory procedur e takes five days, and previously used fast tests are unsatisfactory f or various reasons, tests were made on the Nissin Electric BOD-2000 in strument, which uses a yeast-based biosensor to measure soluble BOD in 30 min. It has been used successfully in the pharmaceutical and food industries. An initial attempt was made to place the instrument in fie ld service. This attempt was unsuccessful, so the present study concen trated on comparing its operation in the laboratory with the results o f the standard five-day BOD test (BOD,) procedure. The two types of te sts were compared for samples from Terminal Island Treatment Plant (TI TP), Bureau of Sanitation of the city of Los Angeles, using various co mbinations of filter porosities and wastewater sources in an attempt t o establish a measurement routine that would not suffer from clogging problems that plagued the held test. Under these conditions the result s from the instrument are excellent, and we briefly discuss further wo rk needed to bring it into field use. This test is believed to be the first effort to assess the capability of this technology in a wastewat er application in the United States.