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The heterocyclic ether 1,4-Dioxane (1,4-DE) is a toxic by-product used widely in various industrial activities as a solvent or stabilizer. 1,4-DE was classified as a probable human carcinogen according to the United States Environmental Protection Agency (USEPA) due to its chemical and physical properties. Emerging pollutants in industrial wastewater is the major challenge for the operation of effluent treatment plant. The bioremediation of 1,4-DE is an effective approach to treat the industrial wastewater. The bacterial consortium was obtained from industrial sludge samples, Yanbu, Saudi Arabia and enriched in 1,4-DE supported basal salt saline medium. Biodegradation of 1,4-DE was studied at several concentrations ranging from 200 to 1200 mg/L. Complete mineralization of 1,4-DE from 200 to 800 mg/L was achieved in 4 to 8 days at 4% salinity. 1,4-DE utilization was studied at different salinity (4% and 6%), the results exhibited complete mineralization of 1,4-DE at 4 days and 6 days respectively. Increase in salinity to 8% displayed 92% degradation of 1,4-DE. Addition of yeast extract accelerated the biomass production correspondingly reduced the time required for biodegradation under saline condition. The bacterial consortium showed the ability to degrade 1,4-DE completely at various range of concentrations. Lab scale continuous stirred tank reactor (CSTR) was used to evaluate the industrial wastewater treatment efficacy of the bacterial consortium under saline condition. CSTR operated for 36 days displayed chemical oxygen demand (COD) removal and 1,4-DE degradation of 96% under saline condition. THF (Tetrahydrofuran) which accelerated the degradation process of 1,4-DE was completely degraded in 28 days. Bacterial analysis with high throughput sequencing technique confirmed the existence of bacterial strains like Ochrobactrum (45%), Marinobacter (21%), Stenotrophomonas (16%), Pseuodomonas (9%), Sphingomonas (4%), Bacillus (3.5%) and Sedimentibacter (1.5%). [ABSTRACT FROM AUTHOR]

The halophilic consortia were enriched from water samples of Abhor, Red Sea, Jeddah, Saudi Arabia for the degradation of phenanthrene, fluorene, hexadecane, pyrene, and treatment of automobile service station wastewater under saline conditions (4%). Complete degradation of phenanthrene and fluorene was recorded up to a concentration of 500 mg.L-1 in 12 days, when the concentration was raised to 800 mg.L-1, the percentage of degradation of the two compounds was recorded by 84 and 90% within 14 days, while when the concentration increased to 1000 mg.L-1, a significant decline was recorded. Pyrene degradation was studied under saline conditions, where it recorded a degradation rate of 92 and 81% at a concentration of 50 and 100 mg.L-1 in 10 and 12 days, respectively, while when increasing the concentration, a severe decrease in the percentage of degradation was recorded that reached 57 and 44% at concentration 200 and 300 mg.L-1, respectively .Hexadecane recorded complete degradation at a concentration of 0.5 and 1%, within 4 and 6 days, respectively, while at a concentration of 1.5%, the rate of deterioration was 88% in 10 days. Record 93% removal of COD in CSTR within 40th day, when treatment of automobile service station wastewater with halophilic bacterial consortia. The existing bacterial strains were classified as potentially responsible for petroleum hydrocarbon degradation and treatment of automobile service station wastewater such as Ochrobactrum, Propionispira, Martelella, Bacillus, Marinobacter, and Azospira. The present study recommends that the hydrophilic consortia can be used in the treatment of automobile service station wastewater under saline conditions. [ABSTRACT FROM AUTHOR]

Concern about increasing incidents of petroleum hydrocarbon spills and spillage into different marine environments is rising day by day due to enhanced human activities in marine water. The toxic compounds of spilled petroleum hydrocarbon in marine water lead to the immediate death of numerous marine organisms as well as initiate various vicious biogeochemical cycles in the marine environment resulting in prolonged toxic impacts on the marine environment. Recently, many sophisticated techniques, including physical methods, chemical methods, and biological methods, have been developed and adopted for the treatment of marine environments polluted with petroleum compounds. However, biological treatment is one of the most promising methods in this field by which microorganisms such as bacteria, fungi, and algae are used for biodegradation of pollutants such as the spilled petroleum hydrocarbon into neutralized or eco-friendly compounds. This review has been focused on different aspects of the pollution of the marine ecosystem by oil, mainly Petroleum hydrocarbons, the fate of spilled oil in marine environments and the role of microbial communities in it, as well as various techniques, especially the bioremediation and biodegradation of spilled oil including the factors affecting the capacity of techniques. Moreover, some future aspects of research in the field of biodegradation and bioremediation of spilled oil have been proposed. [ABSTRACT FROM AUTHOR]

Bacterial degradation of phenols in the environment is influenced by number of factors such as salinity, pH, temperature, and nutrient availability. Halophiles are the group of microorganisms which could grow at saline conditions and thus renders a variety of environmental applications. Moderate halophiles can grow at 3–5% NaCl concentration and are able to utilize a diverse class of toxic pollutants persists in the environment as a result of industrial activities. The moderately halophilic bacterial consortia enriched from wastewater collected from Industrial Effluent Treatment Plant of Yanbu, Saudi Arabia utilized phenol as sole carbon source for its growth. The halophilic consortia could survive and utilize phenol at higher salt concentrations (8% and 12% NaCl). Yeast extract supplied as additional substrate significantly enhanced the phenol biodegradation at higher salt concentrations. The consortia effectively degraded 100% of added phenol within 4 days at haloalkaline conditions (4% NaCl, pH 10). Addition of urea as alternate nitrogen substrate greatly reduced the lag time of the bacterial consortia for the phenol biodegradation. PCR‐DGGE analysis of the moderately halophilic bacterial consortia revealed the presence of three dominant strains which are identified as Ochrobactrum sp. SAR1, Pseudomonas sp. SAR2, and Ochrobactrum sp. SAR3. Through this study, the moderately halophilic bacterial consortia can serve as versatile candidate for the treatment of phenol present in saline and alkaline industrial wastewaters. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1587–1593, 2018 [ABSTRACT FROM AUTHOR]

Clean-up of contaminated wastewater remains to be a major challenge in petroleum refinery. Here, we describe the capacity of a bacterial consortium enriched from crude oil drilling site in Al-Khobar, Saudi Arabia, to utilize polycyclic aromatic hydrocarbons (PAHs) as sole carbon source at 60°C. The consortium reduced low molecular weight (LMW; naphthalene, phenanthrene, fluorene and anthracene) and high molecular weight (HMW; pyrene, benzo(e)pyrene and benzo(k)fluoranthene) PAH loads of up to 1.5 g/L with removal efficiencies of 90% and 80% within 10 days. PAH biodegradation was verified by the presence of PAH metabolites and evolution of carbon dioxide (90 ± 3%). Biodegradation led to a reduction of the surface tension to 34 ± 1 mN/m thus suggesting biosurfactant production by the consortium. Phylogenetic analysis of the consortium revealed the presence of the thermophilic PAH degraderPseudomonas aeruginosastrain CEES1 (KU664514) andBacillus thermosaudia(KU664515) strain CEES2. The consortium was further found to treat petroleum wastewater in continuous stirred tank reactor with 96 ± 2% chemical oxygen demand removal and complete PAH degradation in 24 days. [ABSTRACT FROM AUTHOR]

Pharmaceutical wastewater with different toxic recalcitrant materials and high salinity requires a novel treatment technology before released into the environment. The present research details the treatment of pharmaceutical wastewater along with energy production using bioaugmentation of halophilic consortium in air cathode microbial fuel cell (ACMFC) under saline condition (4%). Organic load (OL) varied from 1.04 to 3.51 gCOD/L was studied in ACMFC. TCOD (Total Chemical Oxygen Demand) removal exhibited 65%, 72%, 84% and 89% at 1.04, 1.52, 2.01 and 2.52 gCOD/L OL respectively. SCOD (Soluble Chemical Oxygen Demand) removal of 60%, 66%, 76% and 82% was recorded during the operation of identical OL (1.04–2.52 gCOD/L). Prominent TCOD (92%), SCOD (90%), TSS (Total Suspended Solids) removal of 73% was attained at 3.02 gCOD/L OL with corresponding energy production of 896 mV (Current density (CD) - 554 mA/m2, Power density (PD)-505 mW/m2). CE (Columbic Efficiency) was 43%, 38%, 33%, 30%, 28% and 22% at different OL ranged between 1.04 and 3.51 gCOD/L. Increase in OL to 3.51 gCOD/L revealed decrement in TCOD (68%), SCOD (62%), TSS (52%) removal and energy production (CD-234 mA/m2, PD-165 mW/m2). Complete removal of phenol was accomplished at different OL in 6 (1.04, 1.52 gCOD/L) and 8 (2.01, 2.52 and 3.02 gCOD/L) days respectively. Ochrobactrum , Marinobacter , Bacillus and Rhodococcus were the dominant halophilic electrogenic strain in ACMFC at different OL. [Display omitted] • Pharmaceutical wastewater treatment and bioenergy production in air cathode MFC. • Total and soluble COD removal was 92% and 90% at 3.02 g COD/L OL. • Complete removal of phenol in 6 and 8 days at different OL. • Maximum power density (505 mW/m2) accomplished at 3.02 g COD/L OL. • Ochrobactrum , Marinobacter , Bacillus , Rhodococcu s dominated the bacterial profile. [ABSTRACT FROM AUTHOR]