| 生活污水污泥制备的生物质炭对红壤酸度的改良效果及其环境风险 |
| 摘要点击 2573 全文点击 1276 投稿时间：2011-12-21 修订日期：2012-03-12 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 污泥 生物质炭 红壤 酸度改良 环境风险 |
| 英文关键词 wastewater sludge biochar red soil amelioration of acid soil environmental risk |
|
| 中文摘要 |
| 采用厌氧热解方法由采自南京市生活污水处理厂的2种污泥分别在300、500和700℃下制备生物质炭,测定了污泥和污泥生物质炭的性质和重金属含量,研究了污泥和污泥生物质炭对酸性红壤的改良效果,并探讨了污泥炭中重金属的环境风险,以考察污泥生物质炭在红壤地区农用的可行性. 结果表明,污泥和污泥炭中含有一定量的碱,添加污泥和污泥炭均可提高红壤的pH值,但污泥中有机氮的矿化和铵态氮的硝化会引起红壤pH波动. 90 d培养实验结束时,500和700℃下制备的污泥炭的改良效果远高于污泥. 污泥和污泥炭中含有丰富盐基阳离子,添加污泥和污泥炭提高了土壤交换性钙、镁、钾和钠含量,降低了土壤交换性铝和交换性H+含量. 污泥制备成生物质炭后重金属含量有所增加,但除Zn和Cd外,Cu、Pb、Ni和As含量没有超过国家标准. 与污泥相比,城东污泥炭中有效态重金属含量显著降低,说明热解过程可以降低有毒重金属的活性. 90 d培养实验结束后,添加江心洲污泥和污泥炭处理之间土壤有效态重金属含量差异不显著; 添加城东污泥炭处理,土壤大部分重金属的有效态含量低于添加污泥处理. 因此,污泥生物质炭可以用作酸性土壤改良剂,与直接添加污泥相比,污泥生物质炭没有增加土壤重金属的活性和生物有效性. |
| 英文摘要 |
| Biochars were prepared from wastewater sludge from two wastewater treatment plants in Nanjing using a pyrolysis method at 300, 500 and 700℃. The properties of the biochars were measured, and their amelioration effects on the acidity of a red soil and environmental risk of application of sludge biochars were examined to evaluate the possibility of agricultural application of wastewater sludge biochars in red soils. Results indicated that incorporation of both sludge and sludge biochar increased soil pH due to the alkalinity of sludge and sludge biochar, and the mineralization of organic N and nitrification of ammonium N from wastewater sludge induced soil pH fluctuated during incubation. The amelioration effects of biochars generated at 500 and 700℃ on the soil were significantly greater than that of sludge significantly. Sludge and sludge biochar contain ample base cations of Ca2+, Mg2+, K+ and Na+ and thus incorporation of sludge and sludge biochar increased the contents of soil exchangeable base cations and decreased soil exchangeable aluminum and H+. Contents of heavy metals in sludge biochars were greater than these in their feedstock sludge, while the contents of Cu, Pb, Ni and As in sludge biochars were lower than the standard values of heavy metals were wastewater sludge for agricultural use in acid soils in China except for Zn and Cd. The contents of available forms of heavy metals in the biochars generated from sludge from Chengdong wastewater treatment plant was lower than these in the corresponding sludge, suggesting that pyrolysis proceed decreased the activity of heavy metals in wastewater sludge. After 90-day incubation of the soil with sludge and sludge biochar, the differences in the contents of soil available heavy metals were not significant between the biochars and their feedstock sludge from Jiangxizhou wastewater treatment plant, and the contents in the treatments with biochars added was lower than these in the treatments with the corresponding sludge from Chengdong wastewater treatment plant for most of heavy metals. It can be concluded that the biochars from wastewater sludge could be used as soil amendments to adjust soil acidity. Application of sludge biochars did not increase activity and availability of heavy metals compared with direct incorporation of the sludge. |
|
|
|
