GENETIC MODEL AND BIOSPECTRAL ANALYSIS FOR MONITORING MUTATIONS IN THE CELL CYCLE FOR APPLICATION IN WASTEWATER TREATMENT

Abstract

The global demand for sustainable development, universal and equitable access to safe and affordable drinking water has garnered a pace of attention in the last two decades. According to World Health Organization (WHO) reports, at least two billion people globally use contaminated drinking water sources for drinking. Contaminated water transmits diseases such diarrhea, cholera, dysentery, typhoid, and polio. It is estimated that by 2025, half of the world’s population will be living in water-stressed areas. Numerous wastewater treatment processes and techniques have been utilized to reduce water pollution and improve drinking water quality. Understanding the behavior of microbial communities in biological processes has been recently the focus of many research studies. Efforts have been made to understand the functional characterization of microorganisms associated with the removal of organics, inorganics and nutrients from wastewater bulking and foaming in activated sludge. The application of electric field to the bioreactors induces electrochemical mechanisms such as electrocoagulation that help not only in municipal wastewater treatment but also in the degradation of pollutants and removal of toxic and hazardous compounds in landfill leachate and industrial wastewaters. Therefore, in this thesis we designed an electrobioreactor which integrates the electrochemical technologies with biological treatment taking into consideration the effects of electricity on bacterial viability in such systems. The main objective of the present research thesis work is to develop and optimize a conceptual model for the functional microbial communities in wastewater treatment electro- bioreactors. The conceptual model proposed is based on 16S rRNA gene high-throughput sequencing data analysis and bioreactor efficiency. The collective data clearly demonstrated that applying various electric currents affected the microbial community composition and stability as well as the reactor efficiency in terms of soluble chemical oxygen demand (sCOD), nitrogen (N) and phosphorous (P) removals for better effluent water quality. Evaluation of the optimum current density 3, 5 and 7 A/m2, hydraulic retention time (6 – 75 h) and other operating conditions such as dissolved oxygen, electrical conductivity, and temperature of the wastewater electrobioreactors were conducted and discussed. The integration of serial passaging technique approach to wastewater electrobioreactors and characterizing the functional microbial communities to enhance sludge settleability were proposed. Based on previous research study conducted in our laboratory, it was investigated that the impact of applying continuous and intermittent electric field at different current densities ranging from 5 – 20 A/m2 affected the bacterial counts in the reactors. We found that low current densities increased viable bacterial cells, while bacterial counts started to decrease at current densities higher than 10 A/m2. These experiments allowed us to conclude that