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的过程，并评估其对圆线虫属（Strongylus spp.）感染性虫卵及幼虫的消减或清除效率。本研究设置的堆肥处理组包括：无翻堆的开放式堆肥，分别采用小体积（CASRm）与大体积（CASRM）；带翻堆的开放式堆肥，分别采用小体积（CAm）与大体积（CAM）；以及厌氧消化罐厌氧堆肥（CF），所有处理均设置3次生物学重复。监测参数为实验周期始末的温度、湿度及寄生虫检出情况。CAM与CASRM堆体中心温度于实验首日达到峰值，约60℃，且仅在前3日维持高于50℃的水平；其余处理组的最高温度约为30℃。实验处理前，可检测到高浓度的圆线虫属幼虫污染（每克样本含25.3条幼虫）。实验结束时，各堆肥组中感染性第三期幼虫的消减率分别为：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。实验结束时，堆体外部湿度约为17%~30%，内部湿度为40%~60%。即便经过堆肥过程与热处理，蠕虫卵仍保持活性。结果表明，仅使用稳定废弃物却未采取恰当处理方式，且采用小体积堆肥时，无法完全清除圆线虫属的虫卵与感染性幼虫。