Koivula Niina, Räikkönen Tarja, Urpilainen Sari, Ranta Jussi, Hänninen Kari
Department of Biological and Environmental Sciences, University of Jyväskylä, P.O. Box 35, FIN-40014, Finland.
Bioresour Technol. 2004 Jul;93(3):291-9. doi: 10.1016/j.biortech.2003.10.025.
Our earlier experiments in small composters (220 l) indicated the favourable effect of ash from co-incineration of sorted dry waste on the composting of catering waste. The aim of this new study was to clarify further, at a scale of 10 m3, the feasibility of using similar ash as an additive in composting. Source-separated catering waste was mixed with bulking agent (peat and wood chips) and fuel ash from a small (4 MW) district heating power plant. Three compost mixes (CM) were obtained: CM I with 0%, CM II with 10% and CM III with 20 wt.% of fuel ash. These three different mixes were composted in a 10-m3 drum composter as three parallel experiments for 2 weeks each, from January to April 2000. After drum composting, masses were placed according to mixing proportions in separate curing piles. The catering waste fed to the drum was cold, sometimes icy. Even then the temperature rapidly increased to over 50 degrees C. In CM III, the temperature rose as high as 80 degrees C, and after the first week of composting the temperature was about 20 degrees C higher in the CMs II and III than in the CM I. It also improved the oxygen concentrations at the feeding end of the drum and obviously prevented the formation of H2S. No odour problems arose during the composting. Addition of ash increased the heavy metal contents of the composting masses, but the compost was suitable for cultivation or green area construction. Ash clearly decreased the loss of total nitrogen in a time span of 2 years. The lower amounts of nitrogen mean that the amounts applied per hectare can be greater than for normal composts. Measured by mineralization, the breaking down of the organic matter was more rapid in the CM III than in the CM I. Humic acid increased steadily during first 12 months composting, from the initial 39 mg/g organic matter to 115 and 137 mg/g in CMs II and III. Measured by temperature, mineralization and humification the addition of ash appeared to boost the composting. Ash had also other beneficial effects on composting it improved the availability of oxygen in compost mass during the drum composting phase and reduced the formation of odorous gases, especially H2S.
我们早期在小型堆肥器（220升）中进行的实验表明，分类干垃圾共焚烧产生的灰烬对餐饮垃圾的堆肥有有利影响。这项新研究的目的是在10立方米的规模上进一步阐明使用类似灰烬作为堆肥添加剂的可行性。源头分类的餐饮垃圾与填充剂（泥炭和木屑）以及来自小型（4兆瓦）区域供热发电厂的燃料灰混合。得到了三种堆肥混合物（CM）：CM I含0%燃料灰，CM II含10%燃料灰，CM III含20重量%燃料灰。这三种不同的混合物在一个10立方米的滚筒式堆肥器中作为三个平行实验进行堆肥，每个实验持续2周，时间从2000年1月至4月。滚筒式堆肥后，按照混合比例将物料放置在单独的熟化堆中。送入滚筒的餐饮垃圾是冷的，有时还结冰。即便如此，温度仍迅速升至50摄氏度以上。在CM III中，温度高达80摄氏度，并且在堆肥第一周后，CM II和CM III中的温度比CM I中的温度高约20摄氏度。它还提高了滚筒进料端的氧气浓度，并明显防止了硫化氢的形成。堆肥过程中未出现气味问题。添加灰烬增加了堆肥物料中的重金属含量，但该堆肥适合用于耕种或绿地建设。灰烬在两年时间跨度内明显减少了总氮的损失。较低的氮含量意味着每公顷的施用量可以比普通堆肥更大。通过矿化作用衡量，CM III中有机物的分解比CM I中更快。在堆肥的前12个月中，腐殖酸稳步增加，从最初的39毫克/克有机物增加到CM II和CM III中的115毫克/克和137毫克/克。通过温度、矿化作用和腐殖化作用衡量，添加灰烬似乎促进了堆肥过程。灰烬对堆肥还有其他有益影响，它在滚筒式堆肥阶段改善了堆肥物料中氧气的可用性，并减少了有气味气体尤其是硫化氢的形成。
