Journal of the Sanitary Engineering Division 

About: Journal of the Sanitary Engineering Division is an academic journal. The journal publishes majorly in the area(s): Waste disposal & Sanitary engineering. It has an ISSN identifier of 0044-7986. Over the lifetime, 623 publications have been published receiving 15759 citations.

Kinetics of Adsorption on Carbon from Solution

Abstract: Laboratory investigations show that rates of adsorption of persistent organic compounds on granular carbon are quite low. Intraparticle diffusion of solute appears to control the rate of uptake, thus the rate is partially a function of the pore size distribution of the adsorbent, of the molecular size and configuration of the solute, and of the relative electrokinetic properties of adsorbate and adsorbent. Systemic factors such as temperature and pH will influence the rates of adsorption; rates increase with increasing temperature and decrease with increasing pH. The effect of initial concentration of solute is of considerable significance, the rate of uptake being a linear function of the square-root of concentration within the range of experimentation. Relative reaction rates also vary reciprocally with the square of the diameter of individual carbon particle for a given weight of carbon. Based on the findings of the research, fluidized-bed operation is suggested as an efficient means of using adsorption for treatment of waters and waste waters.

Unified Basis for Biological Treatment Design and Operation

Abstract: A unified basis for design and operation of biological waste treatment systems employing suspensions of microorganisms is developed from microbial kinetic concepts and continuous culture of microorganisms theory. Biological solids retention time, θ c , average time period a unit of biological mass is retained in the system, is suggested as an independent parameter for process design and control. Steady-state kinetic models are presented for three process configurations, i.e., completely mixed reactor without solids recycle, completely mixed reactor with solids recycle, and plug flow reactor with solids recycle. Reported values of kinetic coefficients are tabularized for: (1) aerobic treatment of carbonaceous wastes; (2) aerobic biological nitrification; (3) anaerobic methanogenic fermentation of carbonaceous wastes. These coefficient values are substituted into the models to determine lower limits, i.e., minimum values of θ c , for each process. Minimum values of θ c of models are compared with θ c values for actual treatment systems.

Floc Breakup in Turbulent Flocculation Processes

Abstract: Floc breakup theories are developed for the complex activated sludge floc and they are applied as well to inorganic chemical flocs. Rate expressions were developed for two modes of breakup in two hydraulic regimes. In one type of breakup it was assumed that primary particles are eroded from the floc surface when the surface shearing forces exceed the shear strength of the bonds joining the particles to the floc surface. The analysis of this surface shearing force required the description of floc motion in the turbulent environment. Expressions were developed for the peak floc size as a function of shearing conditions. The rate of floc breakup was described as the product of the number of metastable floc, the frequency of metastable floc disruption, and the number of primary particles eroded per disruption. A second form of floc breakup was observed experimentally with activated sludge floc. It appeared that the overall integrity of the floc was controlled by a filament mesh running through the floc allowing the buildup of very large floc prior to breakage. The high strength of these filaments seemed to allow the buildup of flocs to sizes that would not be possible in the absence of filaments.

Equilibria and Capacities for Adsorption on Carbon

Abstract: Laboratory investigations show that the ultimate capacity of granular carbon for adsorption of biochemically-resistant organic substances from dilute solution after a sufficient period of contact is on the order of 15% to 25% by weight. Experimental adsorption isotherms for a number of organic substances indicate that adsorption equilibria for solutions of micromolar concentration are well-described by the Langmuir monolayer adsorption theory. Adsorption equilibria for solutions of high concentration appear to be best described by the Brunauer-Emmett-Teller multilayer theory. Interpretation of observed data leads to the conclusion that different types of adsorbed films are formed for high and low concentrations in solution at equilibrium with carbon; the data appear to reveal a range of activities for various parts of the surface area of the adsorbent. Ultimate capacities increase with decreasing temperature, decreasing pH, and decreasing particle size.

Prediction of Stream Reaeration Rates

Abstract: Results are given of many field measurements of actual rates at which river water that is low in dissolved oxygen, but free of organic pollution, absorbs oxygen from atmosphere; by using dimensional analysis and multiple-regression techniques, observed reaeration rates have been related to hydraulic properties of river channels; several reaeration formulas thus developed can be used to predict accurately rate at which oxygen will be absorbed by water flowing in natural stream channels.