Efficacy of Ultrasonic Disinfection in Removing Pathogenic Bacteria From Aquaponic Systems
Discipline: Ecology Environmental and Earth Sciences
Subcategory: Microbiology/Immunology/Virology
Session: 4
Room: Gallery Place
Meilin Scott - Western Washington University
Co-Author(s): Cersey Ochieng, Egerton University, Njoro, Kenya; Dr. Oscar Donde, Egerton University, Njoro, Kenya; Dr. Anne Osano, Bowie State University, Bowie, MD; Dr. Joshua Ogendo, Egerton University; Njoro, Kenya
Aquaponic systems offer a unique approach to solving food insecurity and conserving water resources by integrating aquaculture and hydroponic systems. However, disease from contaminated wastewater has prevented aquaponic systems from becoming an established method of food production. Ultrasonic disinfection technique is a chemical-free and environmentally friendly alternative to wastewater purification. Previous research has demonstrated the technique’s effectiveness in disinfecting municipal sewage waste. However, few studies have applied this technique to aquaponic systems. The objectives of this study were to determine: 1) the effectiveness of ultrasonic disinfection technique and 2) the optimal time of treatment exposure in eliminating pathogenic E. coli and fecal coliforms (CFU) from aquaponic systems. Samples were collected from pond water with Nile tilapia and tank water with Nile tilapia and catfish. Sewage water and distilled water samples were used as positive and negative controls respectively. Samples were subjected to ultrasonic disinfection technique for 0, 20, and 40 minutes. Bacteria were cultured using spread plate technique and colonies were counted. Results demonstrated that ultrasonic disinfection technique was effective in eliminating pathogenic bacteria. There was a significant difference in CFU between raw aquaponic wastewater and treated wastewater for the pond, tank, and sewage samples. 40 minutes was the optimal exposure time for all samples, whereby the lowest CFU values were observed and samples met the agricultural water standards by the FDA. The increase in CFU observed between 0 and 20 minutes of exposure for the pond and tank samples indicated that temperature is likely a factor in eliminating bacteria. Future research includes monitoring the water temperature during the experiment, rerunning experiments using more precise techniques for calculating CFU such as membrane filtration technique or PCR, and integrating ultrasonic disinfection with other techniques like ultraviolet radiation. Evidence suggests that ultrasonic disinfection technique may contribute to effective removal of pathogenic bacteria in aquaponic systems in order to supply safe food on a large-scale while being environmentally friendly and sustainable.
Funder Acknowledgement(s): USDA NIFA AFRI COMPETITIVE GRANT, Grant No. 2020-67038-30659
Faculty Advisor: Dr. Oscar Donde, oscar.donde@egerton.ac.ke
Role: I conducted the experiments and created my oral presentation.