Online Optical Monitoring of BOD/cBOD in Wastewater

Oral Presentation

Prepared by C. Russo1, N. Klinkhammer1, G. Klinkhammer1, D. Hanthorn2
1 - ZAPS Technologies Inc., 4314 SW Research Way, Corvallis, OR, 97333, United States
2 - City of Corvallis, PO Box 1083, Corvallis, OR, 97339, United States


Contact Information: [email protected]; 541-207-1122


ABSTRACT

Because online continuous measurements run automatically, water quality managers need not devote resources to manual sample collection and processing. Rather, these resources can be focused more directly on protecting human health and the integrity of watersheds and aquatic ecosystems- by facilitating greater process control while enabling more timely and effective enforcement of environmental laws and by ensuring compliance with wastewater treatment regulations.

Hybrid Multispectral Analysis (HMA) is an optical approach to online monitoring which uses a combination of in-situ fluorescence, absorption and scattering measurements in a single flow-cell to continuously characterize chemical bonding and molecular structure. In the HMA approach, high intensity light is used to identify molecular bonds and particles in the sample stream enabling the quantification of the oxidants and oxidizers present that ultimately drive oxygen demand. The HMA method’s use of light allows for a very rapid and precise characterization of the sample stream without the need of surrogate microbial seeds, reagents or other sample disruptions. The end result is a more continuous, direct and efficient form of monitoring.

Presented here are results from an entire year of online data measured using the HMA approach to quantify cBOD concentrations in the influent, primary effluent and plant effluent of a 9.7 MGD (dry weather average) hybrid trickling filter, solids contact plant. These data are also compared to smaller (0.25 MGD) and slightly larger (17.5 MGD) treatment plants which together demonstrate an observed diurnal pattern common to wastewater treatment facilities. Data comparison between the HMA and traditional 5-day cBOD analyses are also presented. Finally, the data set is used to discuss seasonal variation, the cBOD response to well-known flow phenomena and how this data can be used by a plant operator to better define the processes at work within the entire sewage delivery and treatment system.