A combined process of two-sludge and induced crystallization was proposed to solve some problems which exist in the traditional processes

such as lack of carbon source

SRT contradictions and low efficiencies for recovery and reuse of phosphorus.Its performance for the removal of organic substrates

phosphorus and nitrogen was investigated.The results showed that the average removal efficiencies of COD

TN

TP were 93.2%

71.2% and 95.7%

when the concentrations of COD

TN

TP and C/N were 152—237 mg·L-1

3.92—7.68 mg·L-1

31.3—50.5 mg·L-1 and 3.91—5.21

respectively.Among those

about 85.9% of the total COD removal was in anaerobic reactor.The share of TN removal in the anaerobic

aerobic

anoxic and post-aeration reactors was 31.7%

11.4%

54.9% and 2.0%

respectively

and the anoxic reactor took the most.The induced crystallization played a major role in removing phosphorus and took about 81.5% of the total removal.The main roles played by two-sludge process were denitrification and assist- chemical removal of phosphorus.Sidestream ratio was a key factor for the stable operation of two-sludge process.An important task of post-aeration reactor was to remove COD and ammonia nitrogen in bypass sludge.