Nutrified Sludge
A new biological treatment process, Nutrification, enables a wastewater treatment plant to remove phosphorus from influent water at an operating and maintenance cost 35% less than that...

Landfill Park: From Eyesore to Asset
By reclaiming a 50 acre landfill as a recreational area, Cambridge, Mass. increased its open space by 20%. The park includes three softball and three soccer fields, one multisport field,...

Air-Water Transfer: The Role of Partitioning
A review is presented of the role of air-water equilibrium in determining the direction and rate of transfer of chemicals between water bodies and the atmosphere. Because this diffusive...

Formation of Droplets from Bursting Bubbles at an Air-Water Interface
The breakup of an air bubble at a still water surface leads to the formation of two distinct droplet families known respectively as film drops and jet drops. The former are the tiny fragments...

The Effect of Surface Films on Concentration Fluctuations Close to a Gas/Liquid Interface
Modeling of gas/liquid mass transport requires knowledge concerning the behavior of near-surface concentration fluctuations at clean and film-covered gas/liquid interfaces. Previous measurements...

Effect of Temperature on Gas Transfer at Low Surface Renewal Rates
In order to investigate the dependence of gas transfer coefficients on temperature under conditions of low surface renewal rates, laboratory experiments were conducted using simultaneous...

Surface Renewal Due to Large Flow Structures in Open Channel Flow
It is shown that under certain flow conditions, surface renewal cannot be understood as an exclusive result of the bursting occurring near the wall, as proposed by several authors. Flow...

Turbulent Velocity and Gas Concentration Measurements in the Near-Surface Layer
An experiment was undertaken to study the mechanism of interfacial mass transfer. Near-surface liquid turbulence and oxygen concentration fluctuations have been measured in a grid-stirred...

Development of Method for Measuring Near-Surface Turbulence
New techniques for tracking particles in fluid are presented. A method to make micro-capsules which are filled with pure water and covered with a thin film of polystyrene is developed....

Measurement of Wave-Induced Turbulent Flow Structures Using Digital Image Sequence Analysis
The turbulent flow in water close to the wavy wind-stressed water surface has been examined quantitatively in a large circular wind-water tunnel with a flow visualization method using...

A Fluorescence Technique to Measure Concentration Gradients near an Interface
A new fluorescence technique which measures the concentration profile in a mass transfer boundary layer is described. It uses a tracer whose fluorescent intensity is inversely proportional...

Regional Estimates of Gas Transfer Using an Airborne System
The aircraft-based eddy correlation technique was recently used to obtain regional observations of transfer processes of sensible and latent heat as well as carbon dioxide over wetlands...

Tracer Gas Transfer Technique for Shallow Bays
Developmental field tests using propane and Rhodamine WT tracers were conducted to adapt the tracer gas method for use in shallow bays. A special injection box was built to prevent mixing...

From Mean Fluxes to a Detailed Experimental Investigation of the Gas Transfer Process
Three new experimental techniques are discussed which allow a much more detailed investigation of the gas transfer process than any previous techniques. Using heat as a proxy tracer for...

Methane Tracer Technique for Gas Transfer at Hydraulic Structures
Using a simple headspace gas chromatographic technique, gas transfer at several hydraulic structures were investigated. Naturally occurring methane was used as a tracer gas to measure...

Gas Transfer Velocities and Radar Backscatter from the Water Surface
Gas transfer velocities of sulfur hexafluoride, methane, and nitrous oxide were determined in two different wind-wave tanks and related to friction velocity and radar backscatter from...

A Gas Chromatographic Protocol for the Measurement of Krypton Gas in Water
This paper presents the results of a study to investigate the feasibility of using a gas chromatographic (GC) technique for the measurement of non-radioactive krypton gas concentrations...

Characteristics of Low-Slope Streams that Affect O2 Transfer Rates
Multiple-regression techniques were used to derive the reaeration coefficients estimating equation for low sloped streams: K2 = 3.83 MBAS-0.41...

Development of an Expert System for Estimating Stream Reaeration Rates
This paper describes a data base of measured reaeration coefficients organized to assist users with estimating coefficients for rivers and streams with hydraulic characteristics similar...

Volatilization of PCBs From the Great Lakes
The potential volatilization of polychlorobiphenyls (PCBs) and other semi-volatile organic chemicals (SOCs) from Lake Superior and Green Bay, Lake Michigan, is being investigated. The...

 

 

 

 

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