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The objective of this research was to develop amathematical model that simulates and predicts chemical and biological fundamentals ofnitrification in pilot-scale distribution systems and to evaluate kinetic parametersassociated with the fundamentals. Six pilot-scale distribution systems were set up at the WaterScience and Engineering Laboratory on the campus of the University of Wisconsin-Madison. Water from Lake Mendota was used as the source water to the distributionsystems after being treated with conventional alum coagulation and filtration processes.Prior to entering the distribution systems, the treated Lake Mendota water waschloraminated so that the chloramine residual at the end of the system was in a range oftypical levels in full-scale distribution systems (i.e., 0.5~2.5 mg Cl2/L). The freeammonia dose was also controlled at the entrance of the pilot-scale distribution system. Each of the six pilot-scaledistribution systems was set up with two connected tanks designed to behave as twocompletely-mixed-flow-through reactors. In total, the pilot system was comprised oftwelve tanks. Each tank had a unique combination of controlled conditions includingchloramine residual, influent free ammonia concentration, and detention time.Chloramine residuals at the end of each system could be controlled at 0.5 to 1.0 mg Clsub2/sub/Lor 2.0 to 2.5 mg Clsub2/sub/L. Influent excess ammonia concentrations could be controlled athigh (Clsub:/subNHsub3/sub=3:1), medium (Clsub2/sub:NHsub3/sub=4:1), or low levels (Clsub2/sub:NHsub3/sub=5:1). The targetdetention time was 1 day or 3 days. Each tank was connected to a PVC pipe loop with1.27 cm diameter and 7.6 m length. Recycle flow rate in the pipe loop was maintained tomake each tank a completely mixed reactor and, at the same time, could simulate typicallow-flow conditions (e.g. 0.07 m/s, Boe-Hansen et al., 2002) in real distribution systems.Samples were collected regularly at the 1-day tank influent, 1-day tank effluent (same asinfluent to 3-day tanks), and 3-day tank effluent. Sampling data included concentrationsof chloramines, free ammonia, dissolved oxygen, nitrite, nitrate, HPC, and AOB in thebulk water. Ambient conditions temperature and pH were also monitored. Includes 14 references, figure.

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Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 5File Size: 1 file , 430 KB