Treatment procedures for stable waste and reduction or elimination of infective eggs and larvae of the genus Strongylus spp.

The objective of this study was to characterize the processes of composting stable waste and to evaluate the efficiency in the reduction or elimination of infective eggs and larvae of Strongylus spp. The composting treatments were: open, without rotation, in a smaller volume (CASRm) and larger volume (CASRM); open, with rotation, in a smaller volume (CAm) and a larger volume (CAM), and anaerobic in biodigester (CF), in three replicates. The monitored parameters were temperature, moisture and presence of parasites in the beginning and at the end of the experimental period. Temperature at the center of CAM and CASRM reached ita peak on the first day, of approximately 60ºC, being higher than 50ºC only in the first three days. In the other treatments, the maximum temperature was around 30ºC. Before treatments were applied, it was possible to observe high levels of contamination by larvae of Strongylus spp. (with 25.3 larvae per gram). The reduction of infective third stage larvae in the compost at the end of the experiment was of 97% (CAM), 87% (CAm), 90% (CASRM), 100% (CF), and 26% for the CASRm treatment. On the outside it was not possible to detect the presence of the parasite. The humidity outside the compound at the end of the experiment was of approximately 17 to 30%, and internally, of 40 to 60%. Helminth eggs remained viable even after the composting process and heaingt treatment. The results indicate that the mere provision of stable waste without the proper handling and in small volumes does not lead to the total elimination of eggs and infective larvae of Strongylus spp.

本研究旨在表征稳定废弃物堆肥过程，并评估其对圆线虫属（Strongylus spp.）感染性虫卵与幼虫的消减或清除效果。本研究设置的堆肥处理组包括：无翻堆小体积敞口堆肥组（CASRm）、无翻堆大体积敞口堆肥组（CASRM）、翻堆小体积敞口堆肥组（CAm）、翻堆大体积敞口堆肥组（CAM），以及厌氧消化罐厌氧堆肥组（CF），每组设置3次生物学重复。监测参数为试验周期初始与结束阶段的温度、湿度及寄生虫检出情况。CAM与CASRM堆体中心温度在试验首日即达到峰值，约60℃，且仅在前3日维持温度高于50℃；其余各组的最高温度约为30℃。试验实施前，可检测到高水平的圆线虫属幼虫污染，每克样本含25.3条幼虫。试验结束时，各堆肥组的感染性三期幼虫（infective third stage larvae）消减率分别为：CAM组97%、CAm组87%、CASRM组90%、CF组100%，而CASRm组仅为26%；堆体外部未检出该寄生虫。试验结束时，堆体外部湿度约为17%~30%，内部湿度为40%~60%。即便经过堆肥与加热处理，蠕虫卵（Helminth eggs）仍保持存活。研究结果表明，仅对稳定废弃物进行简单堆放而未采取合理调控手段，且采用小体积方式时，无法完全清除圆线虫属的虫卵与感染性幼虫。