Investigate and improve the performance of a sequencing batch reactor under organic shock load conditions: Mathematical model

Acidic shock loads sometimes pose a problem to biological wastewater treatment systems by reducing their performance level to the required discharge level. This research examines the effects of these loads with the aid of laboratory-sized Sequencing Batch Reactors (SBRs). Shock loads of 721.25 to 1515.36mg/L were used in organic shock and their impact on COD ratios was observed. In the present study, the COD clearance was reduced from 89.13 ± 1.19% to 60.88 ± 2.31%. Based on the simulated data, a mathematical model was formulated to predict COD decomposition in the aquifer to understand the correlation of the diffusion rate for organic matter and the organic shock load on the diffusion rate for humic substances, which is as follows: The simulated results have good agreement with those of the experiment with a maximum error of 3.36% at the organic shock load of 1019.20 mg/L. To study the reactor performance under subsequent organic shock loads the influent COD was kept at 1249.50 mg/L for eight batch cycles. Specifically, the analyses revealed that the removal ratios tended to increase with increasing numbers of applied shock loads. Furthermore, COD removal efficiency was determined at different Mixed Liquor Suspended Solids (MLSS) levels (2000-5250 mg/L). Optimal COD removal efficiency was obtained from the highest level of MLSS with 75.81%.