The chemically enhanced primary treatment works in Hong Kong will be upgraded for biological nitrogen removal. This study proposed a novel approach to waive the upgrading by urine source-separation, onsite nitrification and discharge of nitrified urine into sewers to achieve in-sewer denitrification. Human urine was collected and a lab-scale experiment for full urine nitrification was conducted. The results showed that full nitrification was achieved with alkaline addition. Simulation of nitrified urine discharge into an 8-km pressure main in Hong Kong was conducted with a quasi-2D dynamic sewer model developed from a previously calibrated sewer biofilm model. It was assumed that 70% of the residents' urine was collected and fully nitrified on-site. The simulation results revealed that the proposed approach is effective in removal of nitrogen within the sewer, which decreases ammonia-N at the sewer outlet to a level required for secondary effluent discharge in Hong Kong.
Urine nitrification and sewer discharge to realize in-sewer denitrification to simplify sewage treatment in Hong Kong
F. Jiang, Y. Chen, H. R. Mackey, G. H. Chen, M. C. M. van Loosdrecht; Urine nitrification and sewer discharge to realize in-sewer denitrification to simplify sewage treatment in Hong Kong. Water Sci Technol 1 August 2011; 64 (3): 618–626. doi: https://doi.org/10.2166/wst.2011.491
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