自热式高温微好氧污泥消化中氮、磷的转化规律

Transformation of Nitrogen and Phosphorus in Autothermal Thermophilic Micro-aerobic Digestion Process

对自热式高温好氧消化工艺进行改进而形成自热式高温微好氧消化工艺,并通过中试考察了对城市污泥的稳定化效果,以及对有机物的去除和氮、磷的转化情况。结果表明,即使在气温为-2^-5℃的情况下,系统在48 h内就能达到46.8℃的高温状态,污泥消化312 h后对VSS的去除率>38%,达到EPA制定的503条款要求。对运行过程中污泥的氮、磷含量变化作进一步的研究,发现在升温初期氮、磷含量的波动幅度很大,随温度的稳定则其含量也基本趋于稳定,除外界因素对系统中的氮、磷含量有影响外,溶胞作用、聚磷菌的活动可能是导致污泥中磷含量变化较大的主要原因。污泥中分别有接近65%、95%的氮和磷存在于固相中,为将消化后的污泥作为肥料使用提供了可能。

Autothermal thermophilic aerobic digestion process was modified into an autothermal thermophilic micro-aerobic digestion （ATMD） process, and the sludge stabilization, organic removal and transformation of nitrogen and phosphorus were investigated in the pilot-scale test. The results show that even in the case of -2 ℃ to -5 ℃in winter, the system temperature can reach 46.8 ℃ within 48 h, and the removal rate of volatile suspended solids （VSS） is above 38% after 312 h of digestion and a- chieves the standard of EPA. In the investigation of change of nitrogen and phosphorus in ATMD process, it is found that the fluctuation of nitrogen and phosphorus is great at the early stage of temperature rise, and their contents become stable with the stabilization of temperature. Except external factors influencing nitrogen and phosphorus contents, lyocytosis and PAOs activity may be the main reasons for wide variation of phosphorus. Nearly 95 % and 65 % of phosphorus and nitrogen exist in the solid phase, which provides a possibility for using digested sludge as fertilizer.