为了获取优化的污水除磷工艺,基于前期对白云石石灰结晶流化床去除厌氧消化上清液中磷的工艺条件和参数的初步探究,考察了不同酸化程度下白云石石灰释放Mg2+、Ca2+的效果,并根据MAP反应特点,选择出酸化液体积为5、6.5和10 m L,分别对应n...为了获取优化的污水除磷工艺,基于前期对白云石石灰结晶流化床去除厌氧消化上清液中磷的工艺条件和参数的初步探究,考察了不同酸化程度下白云石石灰释放Mg2+、Ca2+的效果,并根据MAP反应特点,选择出酸化液体积为5、6.5和10 m L,分别对应n(Mg)/n(P)为0.6、1.4、2.2进行后续实验。利用响应面法(RSM)对白云石石灰结晶流化床强化除磷工艺的影响因素进行分析和探讨,考察了p H值、n(Mg)/n(P)与停留时间(HRT)(分别记为X1、X2、X3)及各因素之间交互作用对磷去除率的影响,并利用扫描电子显微镜、X射线衍射和傅里叶变换红外光谱对产物进行表征,得出最佳工艺参数为p H=9.5、n(Mg)/n(P)=2.2、HRT=3.0 h。RSM法所建立的回归模型显著,实验精准度、精密度和可信度均在合理范围内,回归方程中X1、X2、X3、X1X2、X1X3、X21、X22、X23对磷去除率影响显著。产物MAP晶形较好,但由于废水的碱度较大(20 mmol/L),产物中含有大量的Ca CO3沉淀。展开更多
Digested effluent of manure (DEM) produced by biogas-plants contains many macro- and micro-nutrients. In an experiment conducted in southern Kyushu (Japan), forage crops cultivated after receiving DEM and chemical fer...Digested effluent of manure (DEM) produced by biogas-plants contains many macro- and micro-nutrients. In an experiment conducted in southern Kyushu (Japan), forage crops cultivated after receiving DEM and chemical fertilizers exhibited similar dry matter yields. From a logistical standpoint, however, DEM in liquid form is difficult to handle and apply due to the low concentration of nutrients. To overcome this shortcoming, we prepared dehydrated DEM (DDEM) by adding DEM to cattle manure without disturbing the manure fermentation process. The objective of this research was to evaluate the effect of DDEM on dry matter yield and nitrogen recovery rate in annual dual-cropping systems (summer crop of maize or sorghum and winter crop of Italian ryegrass) that are typical of the region and to compare these results to commercial cattle manure alone, in combination with chemical fertilizer (CM or CM + CF), or no fertilizer application (NF). In both cropping systems, the DDEM treatment produced similar dry matter yields (2.6 to 3.02 kg·m-2) and apparent nitrogen recovery rates (43% to 53%) as the CM + CF and CM treatments. This suggests that DDEM can potentially replace chemical fertilizers and commercial cattle manure in the region.展开更多
文摘Digested effluent of manure (DEM) produced by biogas-plants contains many macro- and micro-nutrients. In an experiment conducted in southern Kyushu (Japan), forage crops cultivated after receiving DEM and chemical fertilizers exhibited similar dry matter yields. From a logistical standpoint, however, DEM in liquid form is difficult to handle and apply due to the low concentration of nutrients. To overcome this shortcoming, we prepared dehydrated DEM (DDEM) by adding DEM to cattle manure without disturbing the manure fermentation process. The objective of this research was to evaluate the effect of DDEM on dry matter yield and nitrogen recovery rate in annual dual-cropping systems (summer crop of maize or sorghum and winter crop of Italian ryegrass) that are typical of the region and to compare these results to commercial cattle manure alone, in combination with chemical fertilizer (CM or CM + CF), or no fertilizer application (NF). In both cropping systems, the DDEM treatment produced similar dry matter yields (2.6 to 3.02 kg·m-2) and apparent nitrogen recovery rates (43% to 53%) as the CM + CF and CM treatments. This suggests that DDEM can potentially replace chemical fertilizers and commercial cattle manure in the region.
