Multiple adsorption substrates have a synergistic effect on the adsorption and interception of pollutants. Layered substrate layer have significant NH 4 + -N interception capacity due to the unique lower adsorption layer. The addition of polyacrylamide in EGR substrate layer is likely to cause additional nitrogen pollution. Biochar can be used as an excellent modifier to enhance the rainfall runoff pollution interception capacity of EGRs.
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