“…Initial and final dissolved oxygen (DO), pH, and initial dissolved phosphorus (DP) were measured. Analytical methods used in this study were as follows: DO was measured with a DO meter (LDO HQ10, Hack, USA), pH with a pH meter (B-212, Horiba, Japan), DN by persulfate digestionautomated cadmium reduction method (American Public Health Association et al, 1998), DP by persulfate digestion method (Japanese Industrial Standard, 1998), COD Cr by closed reflux -colorimetric method (American Public Health Association et al, 1998) and COD Mn by effective colorimetric method (Ishii and Urano, 1999). All the equipment used were prewashed with diluted hydrochloric acid (1+11) to avoid phosphorus contamination.…”