Compost Recycling of Wood Fiber Waste Produced by Paper Manufacture

The composting of wood fiber waste from the manufacture of newsprint is described, with a mixture of wood fiber waste:sewage sludge at a ratio of 1:1 giving best results in a trial of shoot growth of Pinus radiata. An alternative chemical nutrient amendment (initial C:N ratio of 60:1) gave a plant response which was not significantly different to that of sewage sludge. Over a five month period volume reductions of up to 39 percent were observed in the composts, providing potential savings in subsequent transport operations. Use of uncomposted materials or addition of fly- or screen-ash compost amendment (12.5 percent or 25 percent v /v) was inhibitory to plant growth. Concentrations of some heavy metals in Hobart city sewage (particularly of chromium) were high, precluding its long-term use as a soil nutrient supplement. In view of the high heavy metal content of sewage sludge and its high volume to nutrient ratio, it was concluded that composting with chemical amendment was the preferred option for future investigation. Such composts would require ash amendment (or lime equivalent) at concentrations lower than those used in this study to counter acidity produced during composting.