Improvement of acidification on dewaterability of oily sludge from flotation

Abstract

a b s t r a c tThis paper presents the improvement of acidification on the dewaterability of oily sludge from a flotation process. Various parameters, including the volume of supernatant water, capillary suction time (CST), and specific resistance to filtration (SRF) were used to evaluate the dewaterability of oily sludge. In addition, floc size distribution and release rates of Al(III) were used to explain skeleton breakage as a result of the acidification treatment. Results show that dewaterability increased obviously as the sludge pH decreased. After 120 min of settling, the volume of supernatant water reached 77% at pH 4.0. Maximum reductions in CST and SRF were 93.1% and 89.2%, respectively. Following acidification, the flocs in the oily sludge achieved a broader particle size distribution and a smaller median diameter [d (0.5)] of 36.0 m (cf. 74.4 m for the raw sample). In addition, lower pH led to a greater rate of release of Al(III). This study verifies that the floc skeleton of oily sludge can be broken through the dissolution of aluminum hydroxide; i.e., acidification enhances the dewaterability of oily sludge by changing the floc structure. All results indicate that acidification is advisable as a pretreatment of oily sludge.

Utilization of oil recovered from biodiesel wastewater as an alternative feedstock for biodiesel production

“…Acidification is widely used to separate oily impurities from polar substances such as wastewater and crude glycerol . In BWW, the emulsion (oil–soap–water) was irreversible acidified by strong acid as descripted in Figure .…”

The U se of P lant B ased S urfactant in R emoval of O il from O ily S ludge via T hermochemical C leaning M ethod

“…The characteristic of semi-solid oily sludge is mainly consists of water (90-99 wt%), waste crude oil (0.5-3 wt%), mineral particles (0.2-2 wt%) [4], [6] and presence of heavy metals; depending on the nature of wastewater produced at production unit. The semi-solid oily sludge needs to be dewatered and treated via treatment including bioremediation, incineration and composting [6], [7] before it can be disposed.…”

Investigating Dissolved Air Flotation Factors for Oil Refinery Wastewater Treatment

“…Generally, most industrial wastewater treatment companies face the challenge to acquire effective treatment techniques to comply with the environmental regulations, conserve water and present opportunity for pollution reduction (Sahu & Chaudhari, 2013). Currently, most research efforts are being dedicated to process development and optimization such as combination of physical, chemical and biological processes for the effective treatment of ORW (Yavuz et al, 2010;Guo et al, 2011). However, the use of biological processes for treatment of ORW is problematic, sincethe oil composition is not suitable for the growth of microbial community (Diya'Uddeen et al, 2011;Guo et al, 2011).…”

“…Currently, most research efforts are being dedicated to process development and optimization such as combination of physical, chemical and biological processes for the effective treatment of ORW (Yavuz et al, 2010;Guo et al, 2011). However, the use of biological processes for treatment of ORW is problematic, sincethe oil composition is not suitable for the growth of microbial community (Diya'Uddeen et al, 2011;Guo et al, 2011). Chemical treatment is also an essential pre-treatment requirement for the efficient treatment of ORW, since conventional flotation techniques for removing oils are not satisfactory without chemicals (Yavuz et al, 2010).…”