10.2190/96V0-7XNJ-VJNX-7YU4 96V07XNJVJNX7YU4 5 Analyzing Activated Sludge Process Performance Data 185 194 20020509 20020509 20020509 20020509 96V07XNJVJNX7YU4.pdf http://baywood.metapress.com/link.asp?target=contribution&id=96V07XNJVJNX7YU4 2 Tze-Wen Chi Tunghai University, Taichung, Taiwan Because of their important impacts on the environment, the biochemical oxygen demand (BOD) and total suspended solids (TSS) concentrations in effluent streams are critical performance measures for wastewater treatment plants. Wastewater effluent standards often specify the concentration limit for each of these pollutants. Most often, the reported BOD of treatment plant effluent is the sum of the residual unassimilated dissolved BOD and the BOD embedded in escaping biological solids of the clarifier effluent. To meet this effluent standard, a treatment plant must have adequate aeration for substrate removal and sludge formation suitable for separation. This article proposes a method to analyze the activated sludge treatment performance data for the estimation of dissolved BOD and BOD embedded in TSS. the estimation is useful for better control of operation and for the mathematical modeling, by Monod's reaction formulation, that governs the relation between the substrate concentration (S) and bacteria concentration (X). In the secondary clarifier effluent, S is the dissolved BOD while X represents the escaping biological solids or TSS. the proposed method applies the log-linear regression to derive a regression of dissolved BOD on TSS. This basic model is then utilized in conjunction with bootstrap to estimate the dissolved BOD and the BOD embedded in TSS. the analysis of a set of sixty-seven secondary biological municipal wastewater treatment plants yields an estimate of 2.65 mg/ℓ with standard deviation of 1.18 mg/ℓ for dissolved BOD and 0.605 with standard deviation of 0.083 for the ratio of BOD and TSS. A. W. Lawrence and P. L. McCarty, Unified Basis for Biological Treatment Design and Operation, <i>Journal of Environmental Engineering Division</i>, ASCE 96, pp. 757-758, 1970. J. Monod, <i>Recherches sur la Croissance des Culture Bacteriemes</i>, Hermann, Paris, 1942. H. A. Thomas and J. E. Mckee, Longitudinal Mixing in Aeration Tanks, <i>Sewage Works Journal, 16</i>, pp. 42-55, 1944. H. A. Thomas and R. Archibald, Longitudinal Mixing Measured by Radioactive Traces, <i>Proceedings of ASCE 77</i>: a separate no. 84, 1951. N. F. Gray, <i>Activated Sludge: Theory and Practice</i>, Chapter 2, Oxford Press, Oxford, England, 1990. Committee on Water Pollution Management, Engineering Design Variables for Activated Sludge Process, <i>Journal of Environmental Engineering Division</i>, ASCE 106, pp. 475-503, 1980. W. H. Hoven, E. D. Schroeder, and G. Tehobanoglous, Activated Sludge Effluent Quality Distribution, <i>Journal of Environmental Engineering Division</i>, ASCE 105, pp. 819-828, 1979. R. E. Roper, R. O. Dickey, S. Marman, and R. W. Yandt, Design Effluent Quality, <i>Journal of Environmental Engineering Division</i>, ASCE 105, pp. 309-321, 1979. A. H-S. Ang and W. H. Tang, <i>Probability Concepts in Engineering Planning and Design</i>, Vol. I, John Wiley & Sons, New York, 1975. R. R. Sokal and F. J. Rohlf, <i>Biometry</i> (3rd Edition), W. H. Freeman and Co., New York, 1995. Metcalf and Eddy Inc., <i>Wastewater Engineering</i> (3rd Edition), Chapter 8, McGraw-Hill, New York, 1991. T. J. Mcghee, <i>Water Supply and Sewerage</i> (6th Edition), Chapter 22, McGraw-Hill, New York, 1991. S. J. Randtke and P. L. McCarty, Removal of Soluble Secondary Effluent Organics, <i>Journal of Environmental Engineering Division</i>, ASCE 105, pp. 727-743, 1979. C. Z. Mooney and R. Duval, <i>Bootstrapping: A Nonparametric Approach to Statistical Inference</i>, Sage Publications, Newbury Park, California, 1992. B. Efron and R. Tibshirani, <i>An Introduction to the Bootstrap</i>, Chapman & Hall, New York, 1993.