Gaspard Philippe G, Schwartzbrod Janine
Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Faculté de Pharmacie, Nancy, France.
Int J Hyg Environ Health. 2003 Mar;206(2):117-22. doi: 10.1078/1438-4639-00197.
The use of sludge in agriculture must be carried out according to many guidelines, especially regarding a precise knowledge of the pathogenic microorganisms it contains. The control of the produced sludge requires a sampling strategy that is representative of the contamination present in the sludge. Thus, we evaluated the distribution of helminth eggs in sludge to determine how to sample and at what frequency. Two plants were studied, firstly we studied sludge that was undergoing biological treatment (anaerobic digestion, prolonged aeration), secondly we evaluated the dehydration step (centrifugation and filter press). The helminth egg concentrations were measured over short periods (between 5 minutes and 7 hours) and for periods of over 24 hours (7 to 28 days). The results showed that there was much homogeneity in periods of less than 7 hours, thus it was advisable to take grab samples. An appropriate sample weight was 30 g dry matter, because this allowed an analysis in triplicate when testing treatment processes according to standards of France, (less than 3 viable eggs/10 g dry matter). Determination of the egg concentration in the plants during periods of over 24 hours showed that the parasite flow was stable. In some cases, large variations were due to the treatment processes (storage or thickening, mixing of different sludges). These results have been confirmed with the study of 6 other plants during a one year period. Thus, the recommended sampling frequency can be limited to every 3 to 6 months, by adapting the sampling methods to the characteristics of the plant.
农业中污泥的使用必须遵循许多指导方针，特别是要准确了解其中所含的致病微生物。对产生的污泥进行控制需要一种能代表污泥中污染情况的采样策略。因此，我们评估了污泥中蠕虫卵的分布情况，以确定如何采样以及采样频率。我们研究了两家工厂，首先研究了正在进行生物处理（厌氧消化、延时曝气）的污泥，其次评估了脱水步骤（离心和压滤）。在短时间内（5分钟至7小时）以及超过24小时（7至28天）的时间段内测量了蠕虫卵浓度。结果表明，在不到7小时的时间段内，情况较为均匀，因此宜采集 grab 样本。合适的样本重量为30克干物质，因为按照法国标准测试处理工艺时，这样的重量可以进行三次重复分析（每10克干物质中活卵少于3个）。对超过24小时时间段内工厂中卵浓度的测定表明，寄生虫流量是稳定的。在某些情况下，较大的变化是由于处理工艺（储存或浓缩、不同污泥的混合）导致的。在为期一年的时间里，对其他6家工厂的研究证实了这些结果。因此，通过根据工厂特点调整采样方法，建议的采样频率可以限制为每3至6个月一次。
