Performance of seed sludge acclimatized synthetic wastewater in treating chicken slaughterhouse wastewater using upflow anaerobic sludge blanket

• Main Author: Tuan Mohd Marzuki, Tuan Nurfarhana
• Format: Thesis
• Language: English
• Published: 2021
• Subjects: Upflow anaerobic sludge blanket reactors
• Online Access: http://psasir.upm.edu.my/id/eprint/114839/1/114839.pdf; http://psasir.upm.edu.my/id/eprint/114839/; http://ethesis.upm.edu.my/id/eprint/18189

Chicken slaughterhouses generate wastewater rich in organic content and are considered high organic load wastewater, becoming a suitable feedstock for treatment processes that generate electricity. Improper treatment of chicken slaughterhouse wastewater (CSWW) has created severe environmental deterioration especially in surface water. Various treatments have been implemented to treat slaughterhouse wastewater such as dissolved air floatation, coagulation and flocculation processes, conventional activated sludge, lagoon and pond systems, and anaerobic digestion (AD) but meeting limitations to achieve efficiency. Thus, Upflow Anaerobic Sludge Blanket (UASB) reactor was introduced to be the best method for anaerobic treatment. The common drawback in the UASB reactor is the slow start-up process at the early stage of treatment, where the system requires well-developed microorganisms in the seed sludge to degrade the waste. In this study, two sets of UASB reactors, named UASB 1 and UASB 2 were employed to study on the effect of acclimatized seeding sludge using synthetic wastewater (SWW) on reactor process performance and energy generation in treating CSWW. In UASB 1, acclimatization process was not applied on seeding sludge for monitoring purposes, while the seed sludge in UASB 2 was acclimatized using SWW for 30 days. After the acclimatization stage reached a stable state, both bioreactors were fed with the same CSWW at the same organic loading rate (OLR) from 0.5 g/L/day to 6 g/L/day with hydraulic retention time (HRT) of 24 hours and under mesophilic condition (37°C). The Chemical Oxygen Demand (COD) removal efficiencies of UASB 2 were more than 90 % throughout the steady-state of the OLR added. This is equivalent to Specific Methane Production (SMP) of 0.27 LCH4/gCODadded recorded at the optimum OLR of 5 g/L/day in UASB 2 compared to the overall performance observed in the UASB 1. Other parameters such as pH, alkalinity, total ammonia nitrogen (TAN), total suspended solid (TSS), fats, oil and grease (FOG), and colour intensity were analysed to evaluate on the system stability in both reactors. UASB 1 showed some distress in the system when the feeding reached OLR 5 and 6 g/L/day compared to UASB 2, showing stable condition throughout the study. The reactor which contains the acclimatized seed sludge successfully produced a significant methane yield and sufficient removal of COD in the effluent, which met the standard addressed by the Department of Environment Malaysia. The acclimatized seed sludge has fastened the start-up process for the bioreactor with only 30 days compared to other studies as it developed an adequate microorganism to degrade the CSWW. Energy generation for laboratory scale (LS) bioreactor and commercial scale (CS) bioreactor were calculated at 0.0186 kWh and 181.78 kWh per day respectively, using data from optimum performance in UASB 2. This shows that the UASB reactor in CS treating CSWW with acclimatized seed sludge is able to cover the electrical energy required for the chicken slaughterhouse operation of 44 kWh.