Bioremediation of oil-rich wastewater: managing sewer Fats, Oils, and Grease (FOG) deposits with energy uncoupler product

The disposal of Fats, Oils, and Grease (FOG) down drains in both residential and commercial settings results in the buildup of these substances within sewer systems. This accumulation can ultimately lead to blockages and subsequent sewer overflows, posing significant challenges for the water industry. The impacts include potential customer dissatisfaction, negative effects on business operations, and regulatory fines. Effectively managing FOG is a complex issue, and finding viable solutions is paramount. Solutions leading to an alleviation of this problem are of great value, nonetheless, no uniform approaches have been established so far, and the existing measures remain insufficient. FOG bioremediation is emerging as a promising alternative to traditional sewer cleaning methods, but effective, targeted implementation requires higher scientific understanding of FOG deposit formation and modes of action of biological products. This research introduces a novel approach to understanding and addressing FOG deposit formation and treatment. It does so by tailoring these methods to the specific stages of FOG deposit development and utilizing an energy uncoupler product— specifically, a combination of yeast protein extract with surfactants. To substantiate the effectiveness of this approach, comprehensive trials were conducted. These trials encompassed synthetic solutions to simulate deposit formation, preformed synthetic deposits, as well as real deposits collected from the UK's sewerage network. The results of the thesis question and provide an alternative to the currently accepted model of FOG deposit formation through saponification. Instead, the work proposes a two-stage model based on the initial starch-lipid complexation followed by growth through accumulation of fats, lipids, carbohydrates, proteins, and calcium. The study then assessed the uncoupler treatment's impact through two mechanisms of action, i.e., inhibition and rehabilitation, in terms of reducing deposit mass and removing organic fractions present in wastewater. The results provided compelling evidence for the advantageous use of metabolic uncouplers in minimizing FOG deposit formation within sewer systems. Finally, the economic assessment of using the metabolic uncoupler revealed its financial feasibility for both planned and unplanned sewer cleaning procedures through the reduced maintenance that occurred when using it.