From waste to product: Developing pulp and paper mill biosolids into a marketable resource

Paper mill biosolids were evaluated as a secondary resource. The biosolids were found to have levels of regulated compounds below Ontario limits. Pore water and soil samples from land application sites echoed these findings. Growth studies revealed that fresh biosolids used as a soil alternative did not support plant growth and plants suffered from nitrogen deficiency. Results were consistent with historical findings at land application sites. Significant vegetation growth at sites did not occur until one year following application. Carbon to nitrogen testing done at receiving sites showed that over time the biosolids undergo decomposition and stabilize. Greenhouse studies revealed that fresh biosolids were better suited as an organic additive rather than a soil alternative and improved the growth of Jack Pine seedlings. Composting was studied as a stabilization method. After three weeks, the composted material exhibited characteristics of good quality compost according to Ontario Ministry of Environment guidelines.