Both bioretention and sludge biochar have better effects to the removal of nitrogen and phosphorus removal in water. Combining them coulid improve the effect of bioretention on NH4 +. After applying sludge biochar, the adsorption effect of filler on NH4 + was improved. When the sludge biochar was applied to the filler, on the top of the submerged area in the tank, the removal rate of NH4 + could reach 88.62%∼94.48%. ...