Lau S S, Fang M, Wong J W
Department of Biology, Hong Kong Baptist University, Kowloon, PR China.
Arch Environ Contam Toxicol. 2001 Feb;40(2):184-91. doi: 10.1007/s002440010162.
With the increasingly growing global production of sewage sludge, evaluation of its applicability in agriculture and land restoration is essential. This study assessed the potential effects of composting process and fly ash amendment on soil-ameliorating properties of sewage sludge. The metal availability and phytotoxicity of ash-amended sludge compost (AS, mature sewage sludge compost mixed with fresh lagoon ash) and sludge-ash co-compost (SA, co-composted mixture of sewage sludge and lagoon ash) were compared. The results of this work suggested that both composts favored the applicability of sewage sludge for land application by reducing Cd, Cu, Pb, and Zn availability. The SA co-compost stimulated seed germination at ash amendment rates of < or = 10%, whereas various treatments of AS compost inhibited germination at an extract dilution of 50%. Amendment of lagoon ash before or after sludge composting increased electrical conductivity (EC) and volatilization of NH4-N, but lowered availability of PO4-P. Together with the results of phytotoxicity, an optimal ash amendment rate of 5% for AS and 10% for SA were most desirable. Alkaline amendment prior to sludge composting was recommended, because it could be more effective in reducing soluble and plant-available metal concentrations through the composting process.
随着全球污水污泥产量的日益增加，评估其在农业和土地复垦中的适用性至关重要。本研究评估了堆肥过程和粉煤灰改良对污水污泥土壤改良特性的潜在影响。比较了添加灰分的污泥堆肥（AS，成熟污水污泥堆肥与新鲜泻湖灰混合）和污泥-灰共堆肥（SA，污水污泥和泻湖灰的共堆肥混合物）的金属有效性和植物毒性。这项工作的结果表明，两种堆肥都通过降低镉、铜、铅和锌的有效性，有利于污水污泥在土地应用中的适用性。SA共堆肥在灰分添加率≤10%时促进种子萌发，而AS堆肥的各种处理在提取物稀释50%时抑制萌发。在污泥堆肥之前或之后添加泻湖灰会增加电导率（EC）和NH4-N的挥发，但会降低PO4-P的有效性。结合植物毒性结果，AS的最佳灰分添加率为5%，SA为10%最为理想。建议在污泥堆肥之前进行碱性改良，因为它在通过堆肥过程降低可溶性和植物可利用金属浓度方面可能更有效。
