From Day 74, the TP removal efficiency slightly decreased because the influent was shifted to the synthetic wastewater. From Day 74 to Day 120, the average TP removal efficiencies in AES and ANS were 50.70% and 87.34%, and the average final concentration was 3.19 mg L−1.
3.5. FK-228 variations and sulfate generation
The pH value and SO42− concentration in SIBPD were illustrated in Fig. 6. From Day 1 to Day 6, the pH of influent was 7.04–7.12, however, the pH in Effluent A (7.14–7.46) was slightly higher than influent.
Fig. 6. pH variation and sulfate concentration of SIBPD.Figure optionsDownload full-size imageDownload as PowerPoint slide
After Day 7, the pH in Effluent A began to gradually decrease, decreased to 7.01 on Day 59, indicated that the aerobic nitrification became the main reaction taken place in AES and alkalinity would be consumed in the nitrification process.
The pH value in influent was 7.45–7.57 during the real wastewater period from Day 60 to Day 73. Accordingly, the pH of Effluent A varied from 7.13 to 7.38, whereas the pH in Effluent B was always above 7.