PROTOCOLS FOR RESEARCHING THE IMPACT OF SLUDGE GRANULATION ON BNR PROCESSES

Sludge granulation is a leading edge topic at the intersection of two of the most important goals in wastewater biological nutrient removal: process intensification to achieve more capacity from existing infrastructure, and reduction in energy requirements as a means for plants to become net energy positive. This paper discusses the research initiatives undertaken at two wastewater treatment plants with full-scale implementation of sludge granulation by implementing hydrocyclones to separate and retain the heavier biomass fraction of waste activated sludge (WAS). The protocols described herein are used to assess the impacts of sludge granulation on biological nutrient removal (BNR) systems, in particular with regards to biomass settleability and microbial populations, as well as characterizing the nature, activity, and abundance of granules in mixed liquor. This paper is thought to be of great interest to facilities interested in understanding the implications and potential benefits of implementing granule selectors.