Breaking of biochar during compaction of amended soil used in roadside biofilters or landfill cover can affect infiltration, clog amended soil, and change its pollutant removal capacity. It is unknown how the initial biochar size affects the biochar breaking, clogging potential, and contaminant removal capacity of biochar-amended soil. We compacted a mixture of coarse sand and biochar with sizes smaller than, similar to or larger than the sand and applied stormwater contaminated with E. coli in columns packed with the compacted sand-biochar mixture. Coating biochar with a dye and analyzing the dye concentration in the broken biochar particles eluted from the columns, we proved that biochar predominantly breaks under compaction by disintegration or splitting, not abrasion, and increases in biochar size decrease the likelihood of biochar breaking. We attribute this result to the effective dissipation of compaction energy through a greater number of contact points between a large biochar particle and the adjacent particles. Most of the broken biochar particles deposited in the pores, resulting in an exponential decrease in hydraulic conductivity of amended sand with an increase in suspended sediment loading. The clogging rate was higher in the columns with smaller biochar. The columns with small biochar also exhibited high E. coli removal capacity, partly because of an increase in straining by the smaller pore size created by the deposition of fine biochar particles created during compaction. These results are useful in selecting appropriate biochar size for its application in soils and roadside biofilters for water treatment.

在路边生物滤池或垃圾掩埋场中使用的改良土壤压实过程中，生物炭的破裂会影响渗透，堵塞改良土壤并改变其污染物去除能力。尚不清楚初始生物炭的尺寸如何影响生物炭改良土壤的生物炭破损，堵塞潜力和污染物去除能力。我们压实了粗砂和生物炭的混合物，其尺寸小于，类似于或大于沙子，并施加了被大肠杆菌污染的雨水填充有压实的沙子-生物炭混合物的色谱柱中。用染料涂覆生物炭并分析从色谱柱洗脱出来的破碎生物炭颗粒中的染料浓度，我们证明了生物炭在压实过程中主要通过分解或分裂而不是磨损而破裂，并且生物炭尺寸的增加降低了生物炭破裂的可能性。我们将此结果归因于大生物炭颗粒与相邻颗粒之间大量接触点的压实能量的有效耗散。大多数破碎的生物炭颗粒沉积在孔隙中，导致修正后的砂土的水力传导率呈指数级下降，而悬浮沉积物的负荷增加。生物炭较小的色谱柱中堵塞率较高。生物炭较小的色谱柱也表现出较高的大肠杆菌的去除能力，部分原因是由于压实过程中产生的细微生物炭颗粒的沉积而产生的较小的孔径增加了过滤的压力。这些结果可用于选择合适的生物炭尺寸，以用于土壤和路边生物滤池中进行水处理。