用水芹菜种子发芽特性评价污泥堆肥腐熟度和生理毒性

Seed Germination and Root Growth of Cress in Water Extract of Sewage Sludge Compost for Maturity and Phytotoxity

未腐熟的污泥堆肥产品可能对种子发芽和苗期生长产生毒害作用。本研究利用包括水芹菜(cress,Lepidicem sativum L.)在不同堆肥水提取液中的几项指标来指示堆肥的腐熟度。结果表明,不添加猪粪污泥堆肥(TS)和添加猪粪的污泥堆肥(TS-PM)对发芽率、根长和发芽率指数的影响有显著的差别。在堆肥初期,添加猪粪的污泥堆肥水浸提液对种子的毒性明显,较不添加猪粪的污泥堆肥要大,但随着堆肥的进行,堆制100d 后,添加和不添加猪粪的污泥堆肥水浸提液对种子发芽率(GR)毒性减少到零。种子发芽率指数(GI)与水提取液中 NH_4-N,WSC/WSN-or,pH 之间呈明显的负相关,而与 NO_3-N 和有机态氮(WSN-or.)含量呈极显著正相关。添加和不添加猪粪的污泥堆肥 IC_(50)值在堆肥开始时有差异,仅添加猪粪污泥堆肥能计算出 IC_(50)值,以后随着堆肥的进行各堆肥处理的水浸提液在任何浓度和培养时间均不能计算出 IC_(50)值。

Composting is a possible means to treat and reuse sewage sludge produces from wastewater treatment plants.But the residual toxicity of composted products may have ad- verse effects in seedling and crop growth.Some indicators including seed germination was se- lected to evaluate maturity of sludge compost with manure seeding and without manure.The results showed that the pH value,the concentration of WSC and NH_4^+-N in two treatments became very low with composting time,but in the beginnig of composting,the concentration of WSC and NH_4^+-N was very high,especially in sludge with pig manure seeding,and fol- lowing composting time,the same trend was observed for toxicity of compost.Sludge com- post with or without pig manure seeding had a significant inhibition on root growth and seed germination of Lepidiurn sativum L.,but sludge compost with pig manure seeding had a stronger inhibition in seed germination and root growth than sludge compost without pig ma- nure seeding,corresponding to high soluble carbon and NH_4^+-N content of the pig manure added.Besides,the inhibition of sludge compost with or without pig manure seeding had a marked inhibition on seed germination and root growth during the initial period of compost- ing.But after 100 days,seed germination was comparable to that of the control with deion- ized water only.The change of seed germination index was same trend to seed germination and root growth.Seed germination index(GI)is more negative correlated with water soluble chemical indicators including NH_4-N,WSC/WSN-or.and pH,and most positive correlated with NO_3-N and WSN-or.IC_(50)(the concentration causing 50% inhibition of seed germination)value had a great difference in composting treatments,IC_(50)values of sludge compost with pig manure seeding was only 26.9% at 0 day,all of composting treatments could not calculated IC_(50)value at any time and any dose of extract,because there were a higher percentage of compost extract indicating the lower toxicity in compost,so IC_(50)value is not suitable indicator for composting muturity.