Nitrogen and Phosphorus Removal Associated with Changes in Organic Loads from Biological Reactors Monitored by Multivariate Criteria

Abstract

The study aimed to evaluate the techniques of main principal components analysis (PCA) and hierarchical cluster analysis (HCA) as a criterion to monitor the removal of nitrogen forms and phosphorus in sequential upflow anaerobic sludge blanket (UASB), submerged aerated biological filters (SABF), and horizontal subsurface flow constructed wetland (HSSF-CW) treating different organic loads of swine wastewater. System was conducted in four organic loads of swine effluent. The UASB reactor did not provide satisfactory removal of nitrogen and phosphorus. In SABF, dissolved oxygen increased by more than 50 mg L−1 in nitric forms between phases I and IV. The HSSF-CW removed 87.5 and 63.1% and 70 and 42 kg ha−1d−1 of nitrogen and phosphorus, respectively. The PCA showed the effect of salinity and nitrogen/organic load measured and nitrogen and phosphorus removal with high positive correlation (r > 0.80). Two components extracted from the 7 variables were responsible for 81.8, 66.7, and 61.6% of the original influent and effluent data from the UASB, SABF, and HSSF-CW reactors, associated by nutrient removals. There was a reduction in HCA similarity with application of the sequential biological treatment, with the formation of four clusters and the central highlight of the nitrite and nitrate in the SABF reactor. The multivariate techniques presented in this document reduce the number of analyses, maintaining the representativeness of the monitoring data for wastewater treatment.