A fluidized-bed reactor for the photocatalytic mineralization of phenol on TiO-coated silica gel.

TiO photocatalysis represents a promising class of oxidation techniques that are intended to be both supplementary and complementary to the conventional approaches for the removal of refractory and trace organic contaminants in water and air. Powdered TiO dispersion systems employed in most studies require an additional separation step to recover the catalyst from the effluent water, which represents a major drawback for large scale applications. The optimization of photocatalytic treatment systems involves merging the benefits of catalyst immobilization on a retainable support, thus eliminating the need for downstream catalyst separation, maximization of photon-exposed catalyst area, and continuous operation.

Simultaneous removal of oil and grease, and heavy metals from artificial bilge water using electro-coagulation/flotation.

US and international regulations pertaining to the control of bilge water discharges from ships have concentrated their attention to the levels of oil and grease rather than to the heavy metal concentrations. The consensus is that any discharge of bilge water (and oily water emulsion within 12 nautical miles from the nearest land cannot exceed 15 parts per million (ppm). Since there is no specific regulation for metal pollutants under the bilge water section, reference standards regulating heavy metal concentrations are taken from the ambient water quality criteria to protect aquatic life.

Effect of operational parameters on the removal of particulate chemical oxygen demand in the activated sludge process.

The removal of particulate material in the aeration basin of the activated sludge process is mainly attributed to bioflocculation and hydrolysis of particulate substrate. The bioflocculation process in the aeration tank of the activated sludge process occurs only under favorable conditions in the system, and several common operational parameters affect its performance. The principal objective of this research was to observe the effect of mixed liquor suspended solids, solids retention time (SRT), and extracellular polymer substances on the removal of particulate substrate by bioflocculation.

Kinetics of particulate organic matter removal as a response to bioflocculation in aerobic biofilm reactors.

Recent research has identified that the major fraction of chemical oxygen demand in domestic wastewaters is in particulate form. The research presented herein develops the kinetics of particle removal as a response to bioflocculation at the surface of aerobic biofilms. This study focuses on the removal of particles that are maintained in aqueous suspension after 30 minutes of gravity settling.

Kinetics of removal of particulate chemical oxygen demand in the activated-sludge process.

The existing theories incorporated to state-of-the-art, activated-sludge-consensus models indicate that the removal of particulate substrate from the liquid in the activated-sludge process is a two-step process: instantaneous enmeshment of particles and hydrolysis followed by oxidation. However, experimental observations indicate that the removal of particles is not instantaneous and needs a more accurate description. This removal process can actually be described as a three-step process: flocculation, hydrolysis, and oxidation.