Performance and process kinetics of an activated-sludge reactor system treating poultry slaughterhouse wastewater

• Main Authors: Ting-Hsun Hsiao, 蕭庭訓
• Other Authors: Yu-I Huang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/85538385179915000635

博士 === 中興大學 === 生物產業機電工程學系所 === 99 === By taking their averages, the BOD and COD concentrations of poultry slaughterhouse wastewater obtained from a field surrey were 551 and 1127 mg/L, respectively. Poultry slaughterhouse wastewater with such a high BOD/COD ratio of 0.49 discloses that it can be appropriately treated by biological processes. In this work, two small-scale activated sludge reactor (ASR) systems were used. In order to generate practical experimental data and explore the process kinetics of the ASR systems treating poultry slaughterhouse wastewater, two different organic loading rats (0.76 and 1.52 kg COD/m3-d) were operated. At each organic loading rate, four test runs proceeded by varying four different mean cell residence time (θc) (ranging from 4.6 to 24.3 d). Thus, practical performance data of the ASR systems can be obtained. In addition, biomass can also be removed from the steady-state ASRs to evaluate all essential kinetic parameter values (k, Ks, YT, Kd, a and b; required in Monod-model calculation) using the batch reactor method. When the ASR systems were maintained at the same organic loading rate but with four different θc between 4.6 and 24.3 d, the F/M ratio (0.31–1.13 kg COD/kg VSS-d) decreased with increasing θc; the SOUR value (15–33 mg O2/g VSS-h) decreased moderately with increasing θc or decreasing F/M ratio. The obtained maximum specific substrate utilization rate (k) and half saturation constant (Ks) values were 1.7–3.6 mg COD/mg VSS-d and 78–89 mg COD/L, respectively. The k value decreased with increasing θc or decreasing F/M ratio, whereas the Ks value varied slightly with different θc. The obtained true yield coefficient (YT) and decay coefficient (Kd) were 0.34–0.36 mg VSS/mg COD and 0.08–0.16 d-1, respectively. The obtained oxygen-use coefficients for substrate degradation and microbial synthesis (a) and for energy of maintenance (b) were 0.60–0.63 mg O2/mg COD and 0.12–0.19 d-1, respectively. The calculated COD residual concentrations and COD removal efficiencies using the Monod model were 18–39 mg COD/L and 94.8%–97.6%, respectively. The calculated results agree well with the experimental measurements (21–49 mg COD/L; 93.5%–97.2%), implying that Monod kinetics describes well substrate removal rate in the ASR systems treating poultry slaughterhouse wastewater. By respectively varying each parameter value from -100% to +100%, △S/S was linearly sensitive to Ks in the △P/P range of -100% to +100%, but △S/S was highly sensitive to k in the △P/P range of 0% to -40%.