[Effects of Solid Retention Time on the Phosphorus Removal and Nitrosation Granules System].

In this paper, the low C/N ratio of domestic sewage was studied, and mature phosphorus removal granules were inoculated to investigate the effect of solid retention time(SRT)on phosphorus removal and nitrification granular sludge at middle-low temperatures (14-21℃). The test showed that at room temperature (20℃±1℃), the enrichment of AOB in the phosphorus removal granules can be achieved with 30 d SRT and 5 L·(h·L) aeration intensity, while the NAR was over 90%. When the temperature was lowered to 15℃ and the SRT was 40 d, the phosphorus removal performance deteriorated, and the granule structure became loose with the formation of filamentous bacteria.

[Effect of Influent Ammonia Concentration on a Biological Phosphorus Removal Granules System].

Mature biological phosphorus removal granules were inoculated into a SBR. The effect of the ammonia concentration on biological phosphorus removal granules system was investigated by increasing the concentration of ammonia in the influent. The ability of the system to withstand ammonia loading was determined.

[Startup and Stabilization of Nitrosation in an Anoxic-aerobic Continuous-flow Reactor with Granules].

Matured nitrosation granules were inoculated to an anoxic-aerobic continuous-flow reactor at room temperature (17-19℃). The startup and stabilization of nitrosation with granules were studied. The results show that the nitrosation of the continuous-flow was successfully achieved with an average nitrite accumulation rate (NAR) above 95%.

[Effect of Different Ratios of Anaerobic Time and Aeration Time on the Formation of Partial Nitrification Granules].

Flocculent sludge with good nitritation performance and MLSS and SVI values of 3500 mg ·L and 162 mL ·g, respectively, was inoculated in the R1, R2, and R3 groups of the same SBR reactors at room temperature (22-28℃). The effects of different anaerobic time and aeration time ratios (1:2, 1:1, and 2:1) on the formation of partial nitrification granular sludge were studied. The results showed that granules in three reactors were successfully formed at 103 d, 82 d, and 64 d.

[Effect of Aerobic/Phosphorus Granules on Start-up of Partial Nitrification Granular Sludge].

The different effects of additional aerobic granules (AGs) and phosphorus removal granules (PRGs) on the start-up and stable operation of partial nitrification granular sludge (PNGS) were compared at room temperature(22-28℃). The results showed that in the first stage (days 0-22), partial nitrification was accomplished on day 19 for the three reactors (R1, R2, and R3). In the second stage (days 23-56), 20% AGs and 20% PRGs were added to R2 and R3 to induce PNGS.

[COD Requirement for Biological Phosphorus Removal Granule System Under Different Phosphorus Concentrations].

In this study, the effect of COD loading on a biological phosphorus removal granule system under different phosphorus concentrations was investigated by changing the concentration of total phosphorus (TP) and COD in the influent. The lowest concentration of COD for good performance of the biological phosphorus removal system under different phosphorus concentrations was obtained. The results show that when the concentration of TP was 10 mg·L in the influent, the lowest concentration of COD for good performance of the biological phosphorus removal system was 175 mg·L.