| The research was carried out to study the 10-year-old landfill lechate from Shanghai Laogang Landfill in removing nitrogen economically and effectively. The research included part nitritation process in a Sequential Batch Reactor (SBR) and ANAMMOX (Anaerobic Ammonium Oxidation) process in an Upflow Anaerobic Sludge Blanket (UASB) of the 'mature' landfill leachate. Effluent in the former process was produced to fit for the following ANAMMOX, and removal over nitrogen was achieved finally in the latter process. The main experimental results show as follows:(1) Adopted normal activated sludge and modulated Hydraulic Retention Time (HRT), the SBR for part nitritation of 'mature' landfill leachate was successfully started up under the operational condition of temperature 30 ℃, DO 0.81.1mg.l-1. After the star-up, the nitritation rate in the SBR is 200mg.l-1.d-1, and the ratio of NH4+-N/NO2--N in the outlet of SBR is about 1:1.1, which is a fine ammonium/nitrite ratio for the following ANAMMOX.It is not difficult to nitritating for 'mature' landfill leachate with its many natural advantages, such as low BOD5, high ammonium concentration, and high alkalinity etc.(2) The ANAMMOX reactor was inoculated with anaerobic granular sludge and nitritating sludge (from the SBR) and was performed at 35℃, HRT 2d for more than 4 months. The influent concentration of NH4+-N or NO2--N respectively was 250mg.l-1, NH4+-N removal efficiency was 85% and NO2--N 95%. ANAMMOX was inhibited by high NO2--N concentration (300mg.l-1). When volumetric load of NH4+-N (or NO2- -N) was 500g.m-3.d-1(T 35℃, HRT 0.5d), NH4+-N removal efficiency was 84% , removal rate was 384g.m-3.d-1 and NO2--N was 81%, 406g.m-3.d-1.When a SBR can provide a fine part-nitritating influent for ANAMMOX reactor, and a large volumetric load can also be achieved (500g.m-3.d-1), how to inhibitANAMMOX by NCV-N (a high concentration or accumulation in the reactor) and how to keep activated sludge in the ANAMMOX reactor should be studied further. |
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