Fecal Coliform Decay and Regrowth Kinetics in an Anaerobic Dairy Wastewater Environment
The kinetics of fecal coliforms (FC) decay and regrowth were analyzed under laboratory conditions using filtered dairy wastewater under anaerobic conditions.
The mean specific growth rates during the regrowth phase, µr , in the batch study were 1.79, 1.46, and 1.27d-1 for initial organic carbon concentrations of 478, 235 and 127 mg/L COD, respectively. The substrate concentrations had a significant impact on the FC regrowth. A maximum specific growth rate (mmax) of 1.92 d-1, and half-saturated coefficient (ks) of 60.92mg/L were determined from these data.
The mean dark FC decay rate coefficients, kd , at 35oC in the batch study were 2.19, 2.52 and 3.29 d-1 for organic carbon concentrations of 478, 235 and 127 mg/L COD, respectively. The effect of substrate concentrations on the FC dark decay rate coefficient was significant (P-value=0.0004). A simple linear regression equation of kd= 3.460-0.00497 *S was obtained for the batch study.
The decay rate coefficients of FC, determined from non-steady state data, for hydraulic retention times of 1.7, 3.5, and 6.9days at 25oC were 1.34, 1.57, and1.38 d-1, respectively.
The mean µr values in the CSTR at 35oC were 0.83, 2.85, 2.68, 2.29, 2.11 d-1 for the hydraulic retention times of 1.7, 3.5 (Trial 1), 3.5 (Trial 2), 3.5 (Trial 3) and 6.9days, respectively. mmax of 4.00d-1, and ks of 275.12mg/L were obtained for the CSTR studies. mmax of 3.03 d-1, and ks of 169.01mg/L was obtained for the combined data from batch and CSTR studies.
The mean kd-ìd values determined from the non-steady state data for hydraulic retention times of 1.7, 3.5 (Trial 1), 3.5(Trial 2), 3.5 (Trial 3), and 6.9days at 35oC were 4.67, 1.72, 0.72, 1.63, and 5.87d-1, respectively. These results indicate that the 3.5days hydraulic retention time reactors were near steady state conditions.
Advisor:Caye M. Drapcho; Eric C. Achberger; Kelly A. Rusch; Richard L. Bengtson
School:Louisiana State University in Shreveport
School Location:USA - Louisiana
Source Type:Master's Thesis
Keywords:biological and agricultural engineering
Date of Publication:04/18/2002