Abstract
Nitrogen (N) and phosphorus (P) must be removed from wastewater to sustain the water quality of receiving bodies. In this regard, algae can be utilized to achieve tertiary wastewater treatment, removing residual N and P; moreover, algae production creates opportunities to enhance overall water resource recovery facility productivity. Research evaluated an integrated fermenter-biological nutrient removal (BNR) process, integrating algae cultured on secondary effluent. It was hypothesized that algae recycled to the fermenter would increase volatile fatty acid (VFA) production. VFAs are critical for BNR stability; however, concurrent addition of N and P (from the algal biomass) could stress the BNR system. Surprisingly, addition of algae decreased VFA production and consumed ammonia, seemingly due to heterotrophic algae growth in the fermenter. Conversely, the BNR system realized no effect from the algal biomass recycling; P removal was consistent with and without algae, while less efficient nitrification but more efficient denitrification was realized.