污泥灰修复农田重金属污染土的养分特性

为了解决中国农田重金属污染带来的环境问题,采用污泥灰对Pb、Cd污染的农田土壤进行修复处理,通过测试修复前后农田土壤的p H、阳离子交换量、土壤肥力、重金属的生物有效性和重金属溶出特性评估了污泥灰添加量对农田重金属污染土养分特性的影响规律。试验结果表明:污泥灰可显著提高农田重金属污染土壤的养分特性,改善农田重金属污染土壤理化性质,随着污泥灰添加量的增加,污染土的p H、阳离子交换量和土壤肥力显著增加,而Pb、Cd的生物有效性和溶出特性明显降低,当污泥灰的添加量为10%时,污染土中Pb、Cd的浸出浓度低于中国《地表水环境质量标准》Ⅲ类水限值。因此,污泥灰在修复农田重金属污染土领域有极大的应用前景,可根据农田土壤实际的污染工况和修复目标,合理选择污泥灰的添加量,保证修复后的农田土壤均满足修复标准。

The Environmental Security Characteristics of Farmland Contaminated Soil Stabilized by Municipal Sludge Ash

In order to solve the heavy metal contaminated soil of farmland in China.Municipal sludge ash was used to stabilize farmland contaminated soil. pH test,cation exchange capacity test,fertility test, heavy metal bioavailability and leachability test were conducted to investigate the environmental security characteristics of farmland contaminated soil stabilized by municipal sludge ash. Results showed that the municipal sludge ash could significantly improved the environmental security and physicochemical characteristics of the farmland contaminated soil.With the municipal sludge ash dosage increased, the pH,cation exchange capacity and fertility of the farmland contaminated soil was significantly increased, the heavy metal bioavailability and leachability of the farmland contaminated soil was changed oppositely.When municipal sludge ash dosage was 10%,the leaching concentration(Pb and Cd) below the threshold allowed by Environmental quality standards for surface water for agricultural used.Therefore, the municipal sludge ash has great application prospect in farmland contaminated soil.The contamination condition and remediation goal of the farmland contaminated soil should be completely considered and scientific measure could be adopted to ensure the effectiveness of municipal sludge ash treatment.