Electrocoagulation of food waste digestate and the suitability of recovered solids for application to agricultural land
Electrocoagulation of food waste digestate and the suitability of recovered solids for application to agricultural land
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DOI：
10.1016/j.jwpe.2021.102121
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发表时间：
2021-08
影响因子：
7
通讯作者：
Matthew Reilly;Andrew P. Cooley;B. Richardson;D. Tito;M. Theodorou
中科院分区：
文献类型：
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作者：
Matthew Reilly;Andrew P. Cooley;B. Richardson;D. Tito;M. Theodorou
来自食物垃圾厌氧消化（AD）的消化物含有肥料营养物（例如P和N），其对于农业目的是有价值的，并且如果处置不受控制则可能对环境有害。在这里，我们应用电凝聚法（EC）处理污泥，分离液体和营养丰富的固体。混凝剂定量电凝聚法（CDEC）用于比较铝和钢阳极处理AD发酵罐的厌氧状态，该发酵罐饲喂代表食物垃圾的受控饮食。当施加0-4.66 mM的金属投加浓度时，发现Fe在帮助去除化学需氧量（COD）方面比Al高出高达29.8%上级。为了减轻板结垢，将悬浮状态稀释至0.25和0.1浓度，以通过连续流电凝聚（CFEC）成功处理。CFEC添加的可溶性P/Fe的最高回收率为22.4 mg-P g-Fe−1。当使用2.33 mM Fe处理0.25稀释度的酒石酸盐时，实现了这一点。与对照相比，这些最佳条件还导致滤液中可溶性P减少4.5 mg L-1（或87.7%），COD去除254 mg L-1（33.2%）。EC处理对滤液中NH 4+浓度无影响。对一系列已知有毒元素（铜、镍、锌、砷、镉、铬、钼和铅）的分析表明，CFEC回收的固体可适用于土地。
Digestates from anaerobic digestion (AD) of food waste contain fertiliser nutrients (such as P and N) which are valuable for agricultural purposes and can be environmentally hazardous if disposal is uncontrolled. Here, we applied electrocoagulation (EC) for treatment of digestates, to separate liquids and nutrient-rich solids. Coagulant-dosing electrocoagulation (CDEC) was used to compare Al and steel anodes for treatment of digestate from AD fermenters fed a controlled diet representative of food waste. When applying metal dosing concentrations of 0–4.66 mM, Fe was found to be up to 29.8 % superior to Al in terms of aiding removal of chemical oxygen demand (COD). To mitigate plate fouling, the digestate was diluted to 0.25 and 0.1 concentrations to enable successful treatment by continuous-flow electrocoagulation (CFEC). The highest recovery of soluble P per Fe added by CFEC was 22.4 mg-P g-Fe−1. This was achieved when using 2.33 mM Fe to treat a 0.25 dilution of digestate. In comparison to a control, these optimal conditions also caused a reduction of 4.5 mg L−1(or 87.7 %) of soluble P and the removal of 254 mg L−1(33.2 %) of COD in the filtrate. The NH4+concentration in filtrate was not influenced by EC treatment. Analyses of a range of known toxic elements (Cu, Ni, Zn, As, Cd, Cr, Mo and Pb) indicates that the solids recovered by CFEC could be suitable for application to land.