Pilot scale investigation and optimization of the moving bed bioreactor (MBBR) as an ammonia removal upgrade technology for lagoon wastewater treatment systems

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Biological treatment is the most common and economical means of ammonia removal in wastewater. However, at cold temperatures nitrification rates decline substantially or become completely impeded in many treatment systems in Canada. Over 1000 aerated lagoon treatment facilities are presently in operation in Canada and due to their large exposed surface areas are subject to low temperatures in the winter. Attached growth processes and specifically the moving bed biofilm reactor (MBBR) has shown promise with respect to low temperature nitrification; however, the MBBR technology has not been studied nor optimized during long exposures to 1ºC, a common temperature of wastewater exiting lagoons during winter months. Furthermore, a fundamental gap in knowledge exists with respect to the response of attached biofilm and embedded microbial communities in wastewater treatment systems exposed to very cold temperatures for long durations. The objective of this research is to investigate and optimize the performance of the MBBR technology as an upgrade treatment for lagoon systems at cold temperatures and further develop a fundamental understanding of attached growth biofilm and biomass characteristics at very cold temperatures. In addition, the study will investigate methods to optimize the treatment efficiency and operational costs of MBBR units during warm temperature and low ammonia concentration conditions in upgrade MBBR systems designed to oxidize high ammonia concentrations at very cold temperatures. Furthermore, the study will characterize the solids exiting the nitrifying upgrade MBBR treatment systems using digital particle size analysis. Next generation genetic sequencing, environmental scanning electron microscopy and confocal laser scanning microscopy in combination with live/dead viability staining and fluorescent in-situ hybridization will be used to investigate the effects of temperature, loading and biocarrier geometry on the biofilm and biomass attached to the MBBR carriers. Ultimately theses advances will help reduce the risks to the environment, fisheries resources, and human health by decreasing the discharge of harmful deleterious substances.