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...
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...
Measurement of Stream Reaeration Rate Coefficients Using Propane Gas
Three determinations of the reaeration rate coefficient, K2, were made on a 1185-m reach of the upper Assabet River in Westborough and Northborough,...
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...
Carbon Dioxide Pressure in Surface Waters of Canadian Lakes
Direct measurements of the partial pressure (pCO2) of carbon dioxide were made in lakes of three study areas: ELA (the Experimental Lakes Area) and...
Epilimnetic Dissolved Oxygen Content and Surface Water Pump Performance
Surface water pumps have been operated and monitored at TVA's Douglas Dam since 1987. The purpose of these pumps is to improve the dissolved oxygen (DO) content of the hydropower...
Gas Transfer Velocities on Lakes Measured with Sulfur Hexafluoride
Gas transfer velocities have been determined on five lakes ranging in size from 0.13 km2 to 450 km2 using...
Technology Development for Auto-Venting Turbines
Experimentation with venting air into the hydroturbines at Norris Dam has convinced the Tennessee Valley Authority (TVA) that this is a viable method for increasing dissolved oxygen (DO)...
A Simple Empirical Model of Aeration at Navigation Dams
In a study of aeration at 28 dams in the upper Ohio River basin, site-specific least-squares linear regression models were used to describe the dissolved oxygen deficit below each dam...
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