Measurement of Organic Nitrogen and Phosphorus Fractions at Very Low Concentrations in Wastewater Effluents

作者：Sattayatewa Chakkrid^*; Arnaldos Marina; Pagilla Krishna

来源：Water Environment Research, 2011, 83(8): 675-683.

DOI：10.2175/106143011X12928814444899

• dissolved organic nitrogen
• dissolved organic phosphorus
• measurement
• ion-exchange pretreatment

The purpose of this study was to develop simple, accurate, and inexpensive measurement protocols for dissolved organic nitrogen (DON) and dissolved non-reactive phosphorus (DNRP) at low levels in wastewater effluents. Two protocols are presented-one to measure DON exclusively, and the other to measure DON and DNRP simultaneously. Currently, DON and DNRP are calculated indirectly by subtracting the dissolved inorganic fractions from the total dissolved concentration, resulting in significant errors. To increase the accuracy of DON measurements, effluent sample pretreatment using ion exchange to remove nitrate was applied. Spectrometric methods were selected to measure the inorganic fractions-the second derivative UV spectroscopy method for nitrate, and the malachite green method for orthophosphate. These methods, combined with the optimized persulfate digestion of the samples, can be used to measure total dissolved nitrogen and phosphorus accurately. The measurement ranges attained were 0.05 to 3 mg N/L for DON and 0.01 to 0.5 mg P/L for DNRP. Water Environ. Res., 83, 675 (2011).

• 出版日期2011-8