To investigate the DPAO performance, i.e. anaerobic P release
and anoxic P uptake capacities, a batch test was conducted here.
The operation procedure is as follows: 0.5 L of sludge sample was
collected after 80 days enrichment operation, and immediately
washed twice with the trace elements solution and filled into an
l L of transformed triangular flask. At the begin of 2 h anaerobic
phase, 0.5 L of synthetic wastewater was added to achieve the initial
COD and P concentrations of 200 mg/L, 5 mg/L, respectively.
After that, 36 mg/L of nitrate solution was added to provide anoxic
condition, in which NaNO3 was used in the simulated nitrate solution,
operated by 4 h. Effluent of at the end of anaerobic and anoxic
phases were both sampled for investigation of P release and uptake
performances.