| Sewage drainage standards become more stringent and a large number of new and existing sewage treatment plants are facing the pressure of the nitrogen and phosphorus discharge standards. For the purpose to prevent the eutrophication, nitrogen and phosphorus removal has become the main national goal of academia. Sewage treatment industry in China is facing the problem of nitrogen and phosphorus removal from wastewater. Intelligent controlling system-sequencing batch biofilm reactor (ICS-SBBR), the developed innovative technology of nitrogen and phosphorus removal from urban sewage in this study has the advantages of operation with a single Structures, no physical partition, and high microbial concentration compared with conventional nitrogen and phosphorus process. ICS-SBBR process creates alternating running (aerobic/anoxic)n environment in chronological order in a unique operation mode. This creates benefit conditions for nitrification, denitrification, aerobic phosphorus uptake and denitrifying phosphorus uptake, and short aeration time and hydraulic retention time, which saves energy, minimizes the area, and reduces the investment in infrastructure.This study investigated nitrogen and phosphorus removal performance and microbial diversity in blended fiber filled ICS-SBBR process under different C/N ratios. The nitrogen and phosphorus removal performance and species composition of denitrifying bacteria and polyphosphate accumulating organisms were also investigated in suspended materials packed ICS-SBBR process.Different C/N ratios and control modes had little effect on the COD and NH4+-N removal but significant effect on TN removal in suspended carrier ICS system and timer controlling system (TCS). When the C/N ratios were 5.0 and 3.3, TN removal efficiencies in ICS were 15.5% and 12.1% higher than those of TCS. The C/N ratio had no obvious effect on phosphorus removal. The mechanism of phosphorus removal in the ICS system was different from the TCS system. In ICS system, anaerobic phosphorus release did not occur, but denitrifying phosphorus removal could occur during the anoxic period, while TCS system was the traditional aerobic phosphorus uptake and anaerobic phosphorus release process. The ICS system saved as much as 40% energy than TCS system, and had a 30% shorter HRT than the TCS. In the ICS system. The environment for microbial growth was (aerobic/anoxic)n and bacteroidetes group, which was the most dominant bacteria, accounts for 45% of community. However, in TCS system, the environment for microbial growth was anaerobic/aerobic, andβ-Proteobacteria group accounted for 37% of communities, which acted as the most dominant bacteria. Different dominant bacterias led to different mechanisms of nitrogen and phosphorus removal within ICS system and the TCS system.In suspended material packed SBBR system, HRT was set HRT were set four kinds of conditions:(3+5) h, (3+6) h, (4+5) h, (2+7) h. HRT had little effect on removal of organic matter, nitrogen and phosphorus in ICS system but had significant effect in TCS system. The removal efficiencies were 82.9%,53.6%, and 69.0%at HRT of (4+5)h, while when the HRT was (2+7)h, the removal efficiencies were 68.4%,48.0%, and 75.7%. The C/N ratio greatly affected TN removal and TN removal efficiencies were 96.3%,89.7%, and 84.3%in ICS system, while in TCS system, removal efficiencies were 89.2%,79.5%, and 76.8%. The C/N ratio had little effect on TP removal. The C/P ratio could not affect TN and COD removal in both ICS and TCS system. Study on denitrifying bacteria and polyphosphate accumulating organisms in suspended material filled SBBR system shown that denitrifying phosphorus removal bacteria was an important part of PAOs, and whether it was dominant flora system depending on inducing conditions. Direct aerobic phosphorus uptake of PAOs existed in the system and could become dominant flora when induced. Phosphorus removal system performed direct uptake of phosphate with high efficiency and short HRT without anaerobic phosphorus release. |
PDF Full Text Request