Application of Cell Immobilization in the Batch Activated Sludge Treatment of Domestic and Poultry Wastewater Using Carbonized Coconut Shell and Carbonized Rice Hull

Domestic wastewater (DWW) and poultry wastewater (PWW) are some of the primary sources of pollution that affect receiving surface and marine waters, potentially causing eutrophication and other environmental concerns. This study aimed to evaluate the effect of cell immobilization in the performance of batch activated sludge treatment (BAST), particularly nitrification and organic matter removal, in DWW and PWW. Two kinds of cell immobilizers were tested: carbonized coconut shell (CCS) and carbonized rice hull (CRH), both of which are produced from biowaste that are abundantly available in the Philippines. The cell immobilizers were applied in batch reactors seeded with activated sludge (AS) from a sewage treatment facility. Ammonia-nitrogen (NH3-N) and chemical oxygen demand (COD) concentrations were measured hourly over 6-hour periods via spectrophotometry. Application of CCS in two batches of AS-seeded BAST of DWW showed a 10.12% increase in average COD removal from 341.27 ± 4.97 mg/L to 375.79 ± 3.79 mg/L and an 18.55% increase in average NH3-N reduction from 23.49 ± 7.77 mg/L to 27.85 ± 4.30 mg/L. On the other hand, application of CRH in two batches of AS-seeded BAST of PWW showed a 10.69% increase in average COD removal from 483.00 ± 28.56 mg/L to 534.65 ± 59.69 mg/L and a 19.92% increase in average NH3-N reduction from 83.06 ± 12.48 mg/L to 99.61 ± 14.63 mg/L. Comparing the performance between the two immobilizers over three batches of BAST, results showed that CCS-immobilization had higher COD removal of 383.34 ± 7.86 mg/L (DWW) and 605.35 ± 34.37 mg/L (PWW) and higher NH3-N reduction of 32.10 ± 4.92 mg/L (DWW) and 144.03 ± 3.25 mg/L (PWW) compared to CRH-immobilization with COD removal of 351.90 ± 29.27 mg/L (DWW) and 557.05 ± 41.10 mg/L (PWW) and NH3-N reduction of 29.44 ± 1.86 mg/L (DWW) and 115.36 ± 17.87 mg/L (PWW). This study has demonstrated that aerobic treatment of DWW and PWW can be improved using cell immobilization, with CCS-immobilization substantially outperforming CRH-immobilization in terms of COD removal and NH3-N reduction.