This study investigates the possibility to achieve aerobic granulation for the treatment of saline shipboard slop wastewater to remove hydrocarbons. Two sequencing batch reactors (SBR) with a working volume of 3.5 L, were used. In the first reactor (R1), granules were previously cultivated with a stepwise increase of salinity and, subsequently, they were gradually adapted to hydrocarbons. In the second reactor (R2), granules were simultaneously adapted to a gradual increase of salinity and hydrocarbons. Both the reactors were operated with an organic loading rate (OLR) of 1.6 KgCOD∙m−3·d−1, by setting a 6-hours cycle. The volumetric exchange ratio (VER) was fixed at 50% and the hydraulic retention time (HRT) was kept at 0.5 days. Five parallel phases of 30 days-duration were studied. When only slop was fed to reactor, in R1 the total suspended solids (TSS) and granules dimension decreased till about 4.7 g∙L−1 and 1.25 mm respectively, probably due to a metabolic inhibition and a breakage of granules. In R2 the TSS concentration stabilized on a value next to 4.4 g∙L−1 and no degranulation was observed (mean diameter ≈ 1 mm), probable due to a biological adaptation and a biodegradation of the adsorbed recalcitrant fraction. In R1, the reduction of total petroleum hydrocarbons (TPH) in liquid phase and the increase of TPH on granules, confirmed that a physical bioadsorption effect was dominant. In R2 a decreasing trend of TPH bioadsorbed on granules, together with a contextual depletion in liquid phase, suggested a probable occurrence of hydrolysis and biodegradation of the bioadsorbed hydrocarbons.
CITATION STYLE
Campo, R., & Di Bella, G. (2017). Shipboard slop treatment by means of aerobic granular sludge: Strategy proposal for granulation and hydrocarbons removal. In Lecture Notes in Civil Engineering (Vol. 4, pp. 544–549). Springer. https://doi.org/10.1007/978-3-319-58421-8_85
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