Potential application of coastal biofilm-coated gravel particles for treating oily waste

Abstract

This paper reports on hydrocarbon-degrading microbial consortia immobilized in biofilms on gravel particles in the intertidal zone of the Arabian Gulf coast. These microorganisms contribute to the self-cleaning of the coasts and, in addition, could potentially be used for cleaning oily industrial waste before its disposal in the open environment. Each gravel particle was found coated with about 100 mg biofilm of blue-green biomass. The predominant phototrophs were the cyanobacteria Dermocarpella and to a lesser degree Lyngbya sp. The most dominant hydrocarbondegrading bacterium in this consortium was Acinetobacter calcoaceticus; minor bacteria included Micrococcus and nocardioforms. The biofilm-coated gravel particles were used in 5 successive cycles of purification of oily sea water. This immobilized microflora was efficient during all cycles in hydrocarbon consumption. In contrast, bacteria adhering to biomass-uncoated gravel particles brought about hydrocarbon degradation in the first few cycles, but then gradually lost their cleaning potential, apparently due to their successive washing out from the particles during successive cycles.

Treatment of mixed domestic–industrial wastewater using cyanobacteria

“…They were also reported as efficient agents for the assimilation of organic matter from contaminated media [4,43,60] as well as transformation and removal of heavy metals [4,34,49]. Not only the polluted wastewater, but also in natural aquatic environments and soil cyanobacteria developed as mats have been successfully used in bioremediation of oil spills in different parts of the world [12,50,51,56].…”

A microbiological study of the self-cleaning potential of oily Arabian Gulf coasts

“…Similar to the microbial mats (Sorkhoh et al 1992), the epilithic consortia comprise both phototrophic partners and oil-utilizing bacteria. Evidence of oil and hydrocarbon attenuation by bacterial cultures isolated from these consortia has been provided in a previous study (Radwan and Al-Hasan 2001). However, unlike those of the mats, the phototrophs in the epilithic consortia are mainly unicellular eukaryotes, namely diatoms.…”

“…Results from our laboratory revealed that indigenous oilutilizing bacteria occur in the Arabian Gulf mainly in association with animate (Sorkhoh et al 1992;Radwan et al 2002Radwan et al , 2005Radwan et al , 2007 and inanimate (Radwan et al 1999) coastal materials, rather than free in water (for a recent review see Radwan 2008). Among the interesting coastal consortia were those coating gravel particles collected from the north which, in laboratory experiments, exhibited oil attenuation potential for oily waste (Radwan and Al-Hasan 2001). Repeated trips along the Kuwait coast of the Gulf showed that these biofilm-coated gravel particles were frequent most of the year in the intertidal zone along the whole coast.…”

Time Dependent Influence of Aerobic Heterotrophic Bacteria Cyanobacteria Interaction during Biodegradation of Poly Aromatic Hydrocarbons

“…The genera of Cyanobacterial reported in previous studies to have degraded hydrocarbons under aerobic conditions include; Aphanocapsa, Anabaena, Microcoleus, Nostoc, Oscillatoria and Phormidium [26]. Microcoleus chthonoplastes and Phormidium corium cultures were observed to have degraded n-alkanes [27]. Oscillatoria sp.…”