Canadian Journal of Chemical Engineering, Vol.98, No.1, 172-185, 2020
The multi-stage vertical bioreactor in water engineering
The excess of nutrients like nitrogen and phosphorous compounds in surface water (ie, coastal areas, lakes, and rivers) is responsible for major economic, public health, and environmental crises. Their impact is measured in multi-billion-dollar losses, in greenhouse gas emissions and severe algal blooms whose toxicity and geographical dimensions are being monitored and recorded. The present paper focuses on four areas, namely: (a) the economic impact of nutrient pollution, (b) a brief glance at the evolution of the technologies associated with nutrient removal from water/wastewater, (c) a review of the existing conventional planar reactors used in nutrient removal plants, and (d) a description of a novel multi-stage vertical bioreactor and its removal performance, microbial ecology, comparative costs, and construction flexibility. This bioreactor with acronym STAR (simultaneous treatment for ammonia/phosphate removal) is the first multistage bioreactor with vertical configuration used for the simultaneous nitrification, denitrification, and biological phosphorus removal from wastewater. The bioreactor shows high nutrient removal efficiencies of over 95% for both phosphorous and nitrogen compounds. Due to its vertical configuration, this bioreactor requires a smaller footprint and its modularity makes it exceedingly flexible to accommodate to the restricted construction spaces in urban areas.