Evaluation and Selection of RBC Models for Design of Domestic Wastewater Facilities
This study evaluated three existing models commonly used for the design of Rotating Biological Contactors (RBC). Operating data from six RBC Treatment Plants located in eastern Massachusetts...
NAPL and Contaminant Transport in the Soil Matrix
A one-dimensional multiphase mass transport model for the migration of a Non-Aqueous Phase Liquid (NAPL) containing sparingly water soluble organics in the unsaturated soil zone is described....
Biological Treatment of PAHs in Soil Residues in Simulated Land Treatment Systems
The lower molecular weight compounds (2 and 3 ring PAHs) are readily degraded by microorganisms. The heavier molecular weight PAH (polycyclic aromatic hydrocarbon) compounds (4, 5 and...
Aerobic Biodegradation of Chlorinated Solvents in Unsaturated Soils
A potentially attractive application of methylotrophic bacteria is in the treatment of contaminated, unsaturated soil. Methane and air could be supplied by injection and withdraw wells,...
Trio of Microcomputer Models for Organic Chemical Transport in Rivers
Three microcomputer models have been jointly developed to provide tools to simulate the fate of organic chemicals in river systems. The three models offer a range of complexities and data...
Environmental Analysis of Sludge Disposal Options
In a Court-ordered agreement to eliminate disposal of sludge from its treatment plants into the ocean, the City of Los Angeles was required to evaluate alternatives for transporting and...
Conversion of Mixed Waste to LSA Waste?A Case Study
This paper describes a treatment process that was successfully employed at the National Guard Armory in Chicago, Illinois, to convert sludge classified as hazardous chemical/radioactive...
The Utilization of a Deflocculant to Decrease the Permeability of a Clay Liner
A hazardous waste landfill was completed in Oklahoma during 1988. The clay liner was constructed to fulfill the RCRA requirements for permeability of equal to or less than 1E-07 centimeters...
Treatment and Disposal Options
Viable treatment and disposal alternatives which can meet stringent environmental regulations and at affordable cost to the agricultural economy present formidable problems. Treatment...
Chemigation Equipment for Protecting Water Quality
Concerns for protecting groundwater quality have brought forth some strict EPA regulations on equipment required for injecting pesticides into irrigation systems. These chemigation equipment...
Simulating Long-Term Sedimentation Trends on the Lower Mississippi River
A one-dimensional numerical model was used to determine long-term aggradation and degradation trends in the lower Mississippi River. Geometry in the model came from hydrographic surveys....
Agriculture and Groundwater Quality
Nitrates and pesticides used in agriculture cause groundwater degradation. Agricultural practices in the U.S. will have to be changed to alleviate the health effects of these chemicals....
Geostatistics in Estimating Chemical Residuals at a Site
Kriging with generalized covariances is used to evaluate the effectiveness of remediation and cleaning of a contaminated site. The goal is to estimate: a) the amount of total volatile...
Odors: The Other Effluent
Neighbors object to unpleasant odors emitted at wastewater treatment plants, and dealing with such odors requires tact as well as technology. The operators and engineers must listen to...
Stabilizing a `Mann'-Sized Sinkhole
On Sept. 21, 1988, a sinkhole suddenly developed beneath a transmission/distribution effluent pipeline on Mann Road in Orange County, FL. Initially it measured 30 ft in diameter and 8...
Studies of Fish Protection Methods at Hydroelectric Plants
Five largely untested but economical fish-protection systems were tested at sites throughout North America. The process of selecting laboratory and field test sites was completed at the...
Waterstop Technology?The Next Chapter
Water leakage through and around failed waterstops in concrete structures can cause serious flooding, damage to equipment, affect structural stability, and pose potential safety problems....
Alternating Direction Oxidation Ditches?A Cost Saving Technology from Denmark
A soon to be released EPA report claims that in Denmark, small alternating direction oxidation ditches (ADOD) save as much as 70% of the cost for conventional oxidation ditches. The alternating...
Foam Over Troubled Toxics
Foams are now being used to control noxious vapor emissions from hazardous waste landfills. Another use of foams is in control of vapors emitted by chemical spills and fires. This article...
Speaking of RISK
With sensitivity, common sense and preparation, an engineer can explain risk effectively and fairly without alienating the public. Risk communicators should use a standard set of terms...
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