Moustafa Moteleb

Bioremediation and Biorestoration of a Crube Oil-Contaminated Freshwater Wetland on the St.Lawrence River

Biostimulation by nutrient enrichment and phytoremediation were studied for the restoration of an acutely stressed freshwater wetland experimentally exposed to crude oil. The research was carried out along the shores of the St. Lawarence River at Ste. Croix, Quebec, Canada. The research determined the effectiveness of fertilizer addition in enhancing the biodegradation rates of residual oil. It further examined the rate at which the stressed ecosystem recovered with and without the addition of inorganic fertilizers and the role of nutrients in enhancing wetland restoration in the absence of healthy wetland plants. Chemical analysis of integrated sediment core samples to the depth of oil penetration within the experimental plots indicated that addition of inorganic nutrients did not enhance the disappearance of alkanes or PAHs. In surface samples, however, hydrocarbon disappearance rates were higher when the metabolic activity of wetland plants was suppressed by the removal of emergent plant growth. These results suggest that oxygen limitation plays a major role in preventing rapid biodegradation of hydrocarbons in anoxic wetland sediment.

Pertubated loading of a formaldehyde waste in an anaerobic granular activated carbon fluidized bed reactor

The objective of this study was to examine the biological treatment of a formaldehyde waste simulating wastewater from a resin production facility. An analysis of degradation of a high strength organic waste stream containing formaldehyde in an anaerobic fluidized bed granular activated carbon bioreactor (AFBGAC) is presented. In the first part of this study, the AFBGAC bioreactor was operated for a total of 700 days under four different continuous loading rates, to optimize the hydraulic retention time, until steady state performance was obtained. In the second part, the effect of substrate perturbation on effluent quality was examined by periodically loading the reactor using five distinct perturbation schemes to simulate different production shifts. The feed under the first three perturbation schemes was applied in cycles of 16 h on and 8 h off, 12 h on and 12 h off, and 8 h on and 16 h off. The fourth scheme applied feed at 8 h on and 16 h off with no feed on weekends. The fifth scheme examined the long-term effect of substrate limitation using the 8 h on and 16 h off loading cycle with a feed interruption of 9 days. The organic loading per day was kept constant throughout the feed perturbation study. The reactor removed more than 95% of the dissolved organic carbon content of the waste under both continuous and cyclic loading. Formaldehyde removal rates of up to 99.99% were achieved under continuous loading while removal rates ranged from 97.4% to 99.9% under cyclic loading. Although the AFBGAC failed occasionally due to excessive buildup of attached biomass during the phase of continuous loading, it still maintained excellent overall removal efficiencies. It also showed resilience to substrate limitations and load perturbations under dynamic loadings. The results presented in this study provide a promising strategy to treat inhibitory wastes.

Effect of influent oxygen concentration on the GAC adsorption of VOCs in the presence of BOM

Abstract Two rapid small-scale column tests (RSSCTs) were conducted in combination with a large column adsorber to determine if the small columns could predict the performance of a large column. The adsorbate solution consisted of three volatile organic chemicals (VOCs) in the presence of background organic matter (BOM). Landfill leachate was used as the BOM source. Dissolved molecular oxygen was used as a parametric viriable in the column studies to determine its influence on the breakthrough behavior of the adsorbate solution. The RSSCT, designed according to the assumption of no dependency of the intraparticle surface diffusion coefficient on the activated carbon particle size, accurately predicted the performance of the large column under anoxic conditions (absence of molecular oxygen), but failed to predict its performance under ambient (8 mg 1−1 dissolved oxygen) or oxic conditions (30 mg 1−1 dissolved oxygen). The RSSCT, designed according to the assumption of a linear dependency of the intraparticle surface diffusion coefficient on the activated carbon particle size, accurately predicted the performance of the large column under oxic and ambient conditions, but failed to predict its performance under anoxic conditions. The presence of molecular oxygen in the test environment resulted in an increased adsorption of the BOM on the GAC surface, which in turn, decreased the capacity of the VOCs due to competitive effects.

Optimum Nitrogen Concentration Supporting Maximum Crude Oil Biodegradation in Microcosms

ABSTRACT The purpose of this study was to determine the minimum nitrogen concentration needed by microorganisms to biodegrade crude oil hydrocarbons attached to sand particles in a microcosm simula...

Restoration of an Oil-Contaminated St. Lawrence River Shoreline: Bioremediation and Phytoremediation

ABSTRACT The purpose of this field study was to evaluate bioremediation and phytoremediation in restoring an oil-contaminated freshwater shoreline. Weathered Mesa light crude oil was released intentionally onto small plots in the upper intertidal zone of a study site located along the St. Lawrence River. Treatments were established to examine the effect of nutrient addition and the role of plants (Scirpus pungens) on the removal of oil constituents from the contaminated plots. Fertilizers under evaluation included sodium nitrate, prilled ammonium nitrate, and triple super phosphate. Composite core samples were collected after 0, 1, 2, 4, 8, 12, 16, and 21 weeks for identification of remaining oil constituents by gas chromatography-mass spectrometry (GC-MS). To account for differences because of physical washout, all oil constituents were normalized to the conservative biomarker hopane. Although bioremediation and phytoremediation treatments achieved slightly better degradation of hydrocarbons than natural...