PAPERmaking! g FROM THE PUBLISHERS OF PAPER TECHNOLOGY Volume 1, Number 1, 2015
and Stream Improvement [24] reported that the C:N ratios for paper mill sludge can range from 6 to 115:1. The organic matter content of paper mill sludges ranged from 32.54% to 57.91% with an average value of 44.04%. The high organic matter content is an extra benefit for the soils that will improve soil fertility and enhance the soils’ physical properties.
Table 1. Physico-chemical characteristics of paper mill sludges from different paper mill industry sites. (*PM = Paper mill)
Table 2. Heavy metals content of recycled paper mill sludges of different paper mill sites.
* PM = Paper mill, # Classifications were followed for land spreading of pulp and paper mill sludge by the British Columbia Pulp and paper Association [25], ** Investigation Level for Malaysian soils which the level is taken at the 95th percentile of the heavy metals data for agricultural soils [26]. The K content of the paper mill sludges ranged from 0.02% to 0.42% with an average K content of 0.12% (Table 1) that shows its lower quantity. Generally, pulp and paper mill sludges do not provide significant quantities of K [27]. The Ca and Mg contents ranged from 0.36% – 1.28% and 0.41% – 1.06%, respectively (Table 1). Pulp and paper mill sludges, often contain significant quantities of Ca, and sometimes Mg, in the form of carbonates and hydroxides, and have been proven to effectively neutralise soil acidity. In projects where pulp and paper mill sludges were used to reclaim mine tailings, the liming effect of the pulp and paper mill sludges have proven to be one of the primary benefits to soil fertility [28].
Page 7 of 15
Article 2 – Environment (sludge)
Made with FlippingBook - professional solution for displaying marketing and sales documents online