Recovery of Calcium Carbonate from Wastewater Treatment Sludge Using a Flotation Technique

Abstract

The use of flotation technique for the recovery of calcium carbonate (CaCO 3) from wastewater treatment sludge was investigated in this study. The parameters that were investigated included dosage of floating agents (sodium oleate and sunlight dish liquid) and the percentage solids of the slurry. The experiments were performed by floating sieved and un-sieved materials and CaCO 3 was determined for both conditions as well as from tailings. Initial CaCO 3 analysis for the bulk material indicated that sieved and un-sieved materials had 63.4% and 32.9% CaCO 3 content by weight respectively. The modification of pH was effected by dosing 1g NaCO 3 to both 1000 g of sieved and un-sieved materials which was sufficient to raise the pH of the slurry to 9.5. A lower average recovery of 2.33% was observed on un-sieved material after using sodium oleate as a collector when compared to sunlight liquid of 31.6%. Therefore, it was concluded that for un-sieved material sunlight dishwashing liquid was a better collector compared to the latter. The results of this study proved that there is great potential of recovering commercial grade limestone from wastewater sludge.

Recent Development in Ammonia Stripping Process for Industrial Wastewater Treatment

“…However, the calcium carbonate from the ammonia stripper sludge can be recovered. Maree and Zvinowanda, for example, used the flotation technique to recover calcium carbonate from wastewater treatment sludge [38]. As a result, they discovered that floatation technique can potentially recover commercial grade limestone from wastewater sludge [38].…”

“…Maree and Zvinowanda, for example, used the flotation technique to recover calcium carbonate from wastewater treatment sludge [38]. As a result, they discovered that floatation technique can potentially recover commercial grade limestone from wastewater sludge [38]. Meanwhile, He et al assessed the feasibility and performance enhancement for treatment of alkaline-stripped effluent in aerated constructed wetlands [39].…”

Water and nutrient recovery from urine: A lead up trail using nano-structured In2S3 photo electrodes*

“…[9] Ammonia can be removed by the conventional method of air-stripping, biological treatment, or breakpoint chlorination. [10][11][12] Practically recycling of human urine has been explored using techniques such as alkaline urine dehydration, struvite precipitation, evaporation, reverse osmosis, nitrification, precipitation, ammonia stripping, electro-dialysis, nanofiltration and advanced oxidation. [13][14][15] Distillation is the oldest method and least energy intensive technique for urine recycling.…”

Systematic investigation of interactions of bulk nanobubbles with soft matter

“…Froth flotation is an effective separation method based on the differences in surface hydrophobicity of different particles and has been widely applied in industrial processes, such as mining and wastewater treatment. 49,50,92,97,[102][103][104][105][106][107][108][109][110][111][112] Gases are inherently hydrophobic, thus the recovery in froth flotation begins with the collision and adhesion of hydrophobic particles to the gas bulk bubbles followed by transportation of the hydrophobic nanoparticle-bubble complex from the collection zone to the froth zone, enrichment of the froth, and finally removal from above by overflow, while hydrophilic particles remain and are discharged as tailings. 113 Fan et al…”