磷酸酯酶活性对餐厨垃圾单相厌氧消化抑制的预警作用

为了研究磷酸酯酶活性对餐厨垃圾单相厌氧消化抑制的预警作用,考察了单相CSTR反应器在容积负荷2.0~8.5kgVS/(m3·d)条件下的酸性和碱性磷酸酯酶活性,并同步分析了挥发性脂肪酸(VFAs)、容积产气率、pH值的变化.结果表明,酸性和碱性磷酸酯酶活性在容积负荷为2.0~4.0kgVS/(m3·d)时,平均值为14.1,9.8μgNP/(h·mL);容积负荷为5.0~7.5kgVS/(m3·d)时,其平均值为138.4,23.6μgNP/(h·mL);容积负荷为8.5kgVS/(m3·d)的超负荷阶段达到峰值318.1,51.5μgNP/(h·mL)后快速下降.磷酸酯酶活性骤升的时间较VFAs、容积产气率骤降超前2d、较pH值的骤降提前1d.磷酸酯酶活性较常规指标VFAs、容积产气率和pH值等对单相厌氧消化抑制具有一定的预警作用.

Role of phosphatase activity as an early warning indicator of inhibition in a single-phase anaerobic digester treating food waste

The objective of this study was to understand the role of phosphatase activity as an early warning indicator of inhibition that has been often observed in the anaerobic digestion (AD) of food waste. Tests were conducted in laboratory scale, single-phase CSTR reactors operated at loading rates ranged from 2.0 to 8.5kg VS/(m3×d). The activity of acid phosphatase (ACP) and alkaline phosphatase (ALP), volatile fatty acids (VFAs), volumetric gas production rate and pH were measured during the reactor operation. The average ACP and ALP activity at the start-up phase when the reactor loading rate ranged from 2.0 to 4.0kg VS/(m3×d) were measured as 14.1 and 9.8 μgNP/(h×mL), respectively; while 138.4 and 23.6μgNP/(h×mL) at the steady phase when the reactor loading rate was within 5.0 to 7.5kg VS/(m3×d). The ACP and ALP activity peaked at 318.1 and 51.5μgNP/(h×mL) when reactors were overloaded at 8.5kg VS/(m3×d), after which both activity significantly decreased. The sharp increase in phosphatase activity occurred two days prior to the loading rate increase and one day prior to the pH drop, which suggests it could be an early warning indicator of inhibition that often occurred in the anaerobic digestion of food waste.