BACKGROUND Continuous-flow culture models are one tool for studying complex interactions between members of human fecal microbiotas because they allow studies to be completed during an extended period of time under conditions where pH, nutrient availability, and washout of waste products and dead cells can be controlled. Because many of the existing well-validated continuous-flow models are lar...

Three activated sludge reactors of different sizes and designs, one in pilot-plant-scale of 7,000 gallon liquid volume, and two in benchscales of 7.5 gallon and 1.2 gallon liquid volumes, respectively, were used to evaluate the scale-up effects on the process at outdoor temperatures. The reactors were operated under equivalent conditions by regulating the mean cell residence time, mean hydrauli...

Effect of fractional gas hold-up εG on volumetric mass transfer coefficient KLa were studied for two different type of airlift contactors conventional and modified. KLa was directly proportional to gas hold-up within bubbly flow regime (UG < 0.075 m/s ) in conventional one but reverse trend ( inversely proportional) was reported in modified airlift contactor. Mathematical relation between KLa a...

A simplified method is used to determine the optimum water content in the flue gases of charcoal gasifiers to be utilized as alternative fuels in the operation of engines and gas turbines for power generation. Computational models of plug flow reactors and well stirred reactors are employed to simulate the reaction and post-flame zones, adopting different chemical mechanisms. In the simulations...

An experimental study has been conducted on the effectiveness of two types of flow-altering countermeasures placed around a cylindrical pier under clear water condition, which include sacrificial piles and submerged vanes. Their arrangements follow the optimal configurations recommended in the published articles with some modification. The temporal evolution of maximum scour depth and its equil...

This review is a synopsis of different bioprocess engineering approaches adopted for the production of marine enzymes. Three major modes of operation: batch, fed-batch and continuous have been used for production of enzymes (such as protease, chitinase, agarase, peroxidase) mainly from marine bacteria and fungi on a laboratory bioreactor and pilot plant scales. Submerged, immobilized and solid-...

Packed bed reactor finds wide application in wastewater treatments. Packed bed reactors can be employed for aerobic and anaerobic biological treatment of wastewater. They can also be used for physico-chemical treatments such as activated carbon adsorption of various pollutants from wastewater. Packed beds with up flow and down flow mechanisms are widely used for wastewater treatment. Use of flu...