Author ORCID Identifier:

https://orcid.org/0009-0003-5806-0997

Date of Graduation

12-2025

Document Type

Thesis

Degree Name

Master of Science in Poultry Science (MS)

Degree Level

Graduate

Department

Poultry Science

Advisor/Mentor

Obe, Tomi

Committee Member

Owens, Casey

Second Committee Member

Sun, Xiaolun

Keywords

Advanced Oxidation Processes (AOPs); Campylobacter; Disinfection; Poultry processing wastewater; Reactive Oxygen Species; Salmonella

Abstract

Water is an essential resource used in poultry processing, generating large volumes of foodborne pathogen-rich wastewater posing treats to public health. Treating poultry processing wastewater (PPW) is crucial for safe water reuse and sustainable development. Conventional disinfection methods like aerobic digestion and chlorination, although effective, impose considerable operational cost and generate harmful by-products. Integrated recycling systems such as advanced oxidation processes (AOPs) which destroy micro-organisms through the generation of reactive oxygen species (ROS) present a promising opportunity for enhancing resources and sustainability. This study investigated the use of photo-electrochemical (PEC), specifically by combining electrochemical (EC) and photochemical (PC; Photosensitizer and light) processes to reduce Campylobacter species (jejuni (Cj) and coli (Cc)) individually and in combination with Salmonella Typhimurium (ST) in simulated wastewater. In the Chapter 3 study of simulated PPW experiment, 6 Log10 CFU/ml of Cj, Cc and ST contaminated water was subjected to alternating current in EC treatments with a voltage demand of 50 V and 70 V and ferrous sulfate as a Fenton-related catalyst, alongside PC treatments using curcumin, a photosensitizer at concentrations of 0.8% and 1.6% to generate singlet oxygen and hydrogen peroxide. Samples were collected every 30 min for 300 min and plated on Campylobacter agar that was incubated at 42°C for 48 h. Furthermore, cocktail of Cj and ST was exposed to the same PEC treatments. Bacterial growth was assessed on Campylobacter and XLD agar. Cj was completely disinfected after 150 min (4.70 Log CFU/ml) at 50 V and 120 min (5.97 Log CFU/ml) at 70 V of treatment whereas Cc was disinfected after 210 min (5.68 Log CFU/ml) at 50 V and 180 min (5.99 Log CFU/ml) at 70 V. While the rate of disinfection time varied between Campylobacter species and in response to the voltage of the EC treatment by 30 min, increasing concentration of curcumin in PC treatment had no significant (p< 0.05) impact on bacterial reduction rates. In a mixed population, Cj and ST exhibited complete reduction in 120 min (6.07 Log CFU/ml), establishing an optimal condition of both EC (70 V) and PC (1.6%) for effective removal of both pathogens. Our findings suggest that combined PEC treatments effectively killed Campylobacter and Salmonella in contaminated water, highlighting the potential of AOPs as a sustainable poultry wastewater disinfection strategy. In the Chapter 4 of further study, we demonstrated microbial disinfection of aerobic bacteria (AC), coliforms (CC), Enterobacteriaceae (EB) and E. Coli count including Salmonella and Campylobacter in PPW obtained from the scalder and Inside-outside bird wash (IOBW) stages of poultry processing in both pilot scale and semi-industrial scale (30 L). PPW types were exposed to 70 and 100 V EC combined with 1.60% PC levels for 300 min with samples collected every 30 min for evaluation of Salmonella, Campylobacter, AC, EB, CC and E. Coli disinfection. Although statistically not significant (P> 0.05), treatments at optimized 100 V exhibited quicker disinfection time of pathogens tested compared to the 70 V EC level. This further suggests that PEC treatments are viable and sustainable disinfection strategies for PPW, reducing environmental pollution while promoting safe wastewater reuse in poultry processing operations.

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