A Novel Approach for Stabilizing Heavy Metals in Municipal Solid Waste Incineration (MSWI) Fly Ash Using Waste Fishbone Hydroxyapatite (FB-HAP)

The present research focused on the role of fishbone hydroxyapatite (FB-HAP) in stabilizing heavy metals in municipal solid waste incineration (MSWI) Fly ash (FA) particularly Pb and Zn. Bones from a variety of fish species as well as a commercial apatite (Apatite II^TM) were used. The effect of both substances was studied under different liquid/solid (L/S) and settling periods. Batch tests were conducted under the fishbone/FA ratios of 0.0 and 1:10 by weight and various contact times of 6, 12, 24, and 672 h (28 days) with two different L/S ratios of 1.0 and 1.5 ml/g. The highest Pb and Zn removal efficiency reached 86.39 and 62.67%, respectively, after 672 h when fishbone dosage was 10% at L/S 1.5. Apatite II^TM was also effective for Pb stabilization; however, FB-HAP was more efficient (about 1.5–2 times). The results indicated that both contact time and L/S ratio were the most important factors for enhanced metal stabilization.