Unit of Environmental Engineering, Section of Waste Treatment and Resource Management, Universität Innsbruck, Technikerstraße 13, 6020 Innsbruck, Austria; alpS GmbH, Grabenweg 68, 6020 Innsbruck, Austria.
Unit of Environmental Engineering, Section of Waste Treatment and Resource Management, Universität Innsbruck, Technikerstraße 13, 6020 Innsbruck, Austria.
Waste Manag. 2016 Jun;52:96-103. doi: 10.1016/j.wasman.2016.03.055. Epub 2016 Apr 4.
Although the mechanical treatment of source separated organic waste typically includes processing steps to remove impurities like plastic bags, smaller particles like glass, stones or sand are often not sufficiently removed. These particles lead to plant malfunctions, increased equipment abrasion and accumulation in the digester. It is possible to remove these small impurities before or during the fermentation process but this requires additional equipment at the waste treatment facilities. For pretreated biowaste with fairly low concentrations of impurities and small particle sizes no appropriate method was found in literature to determine these particles. Therefore various approaches to develop an appropriate method were tested and finally one method was selected. Sample mass calculation showed that for the determination of impurities >2mm a sample mass of about 6kg is required to receive statistically sound result. Firstly an elutriation step is used to concentrate the impurities in a sinking fraction, still containing some organic material. The elutriated material is then dried. After drying the elutriated material, impurities can be fairly easily sorted manually. The elutriation process is applicable for the determination of impurities >1mm. Due to the difficult manual sorting of particles <2mm and the reduced sample mass required for the determination of particles <2mm, these particles are determined by a different procedure: A sample mass of about 1kg is dried and combusted in a muffle furnace. The remaining ashes are sieved from 2 to 0.06mm. Particles <0.06mm were not considered as impurities. The data regarding the impurities content and particle size distribution in food- and biowaste are required for assessing separation options as well as the behavior of stones or sand in the digester. This allows describing the quality of the pretreated biowaste. Furthermore the need to adopt or improve the existing pretreatment can be identified and the impact to the fermentation process (impurities accumulated in the digester, etc.) can be evaluated.
虽然源分离有机废物的机械处理通常包括去除杂质（如塑料袋）的加工步骤，但较小的颗粒（如玻璃、石头或沙子）往往不能被充分去除。这些颗粒会导致设备故障、设备磨损增加以及在消化器中积累。在废物处理设施中，可以在发酵过程之前或期间去除这些小杂质，但这需要额外的设备。对于杂质浓度较低且颗粒尺寸较小的预处理生物废物，文献中没有发现合适的方法来确定这些颗粒。因此，测试了各种方法来开发合适的方法，最终选择了一种方法。样品质量计算表明，对于杂质>2mm 的测定，需要约 6kg 的样品质量才能获得统计学上可靠的结果。首先，使用淘析步骤将杂质浓缩在沉降部分中，该部分仍含有一些有机物质。然后对淘析材料进行干燥。干燥后，杂质可以通过手动相当容易地进行分类。淘析过程适用于杂质>1mm 的测定。由于<2mm 颗粒的手动分类困难以及<2mm 颗粒测定所需的样品质量减少，这些颗粒采用不同的程序进行测定：约 1kg 的样品质量在马弗炉中干燥和燃烧。剩余的灰烬用 2 至 0.06mm 的筛子进行筛分。<0.06mm 的颗粒不被视为杂质。需要评估食品和生物废物中的杂质含量和粒度分布数据，以评估分离选项以及石头或沙子在消化器中的行为。这可以描述预处理生物废物的质量。此外，可以确定需要采用或改进现有的预处理，并评估其对发酵过程（杂质在消化器中积累等）的影响。
