Gas Technology Institute

Gas Research Institute

Thomas David Hayes

Vipul J Srivastava

Blaine F Severin

David P Chynoweth

Bhupendra K Soni

Richard Biljetina

H Ronald Isaacson

James R Frank

Methods for improving ion flux and energy efficiency in a membrane stack of an electrodialysis unit wherein the membrane stack is disposed between an anode and a cathode each in an electrolyte of a selected concentration. Methods include increasing the concentration of the electrolyte, adding a strong base to the electrolyte and adding buffering anions to the electrolyte. Methods for cleaning the electrodes of such a unit involving involve applying a pulsed polarity reversal to the electrodes. Also provided are methods for improving unit operation by increasing the basicity of the electrolyte to the anode and increasing the acidity of the electrolyte to the cathode or alternatively or in addition, by applying heat to increase the operating temperature of at least one of the electrolyte and the treated water stream.

Electrolyte chemistry and improved stack performance in high brine concentration electrodialysis

Methods for controlling electrolyte chemistry in electrodialysis units having an anode and a cathode each in an electrolyte of a selected concentration and a membrane stack disposed therebetween. The membrane stack includes pairs of cationic selective and anionic membranes to segregate increasingly dilute salts streams from concentrated salts stream. Electrolyte chemistry control is via use of at least one of following techniques: a single calcium exclusionary cationic selective membrane at a cathode cell boundary, an exclusionary membrane configured as a hydraulically isolated scavenger cell, a multivalent scavenger co-electrolyte and combinations thereof.

Electrolyte chemistry control in electrodialysis processing

A method and apparatus for in-situ measurement of soluble contaminant flux rates from sediments in which an inverted desorption chamber containing a sorbent system is filled with water and placed over an area of sediment, whereby the interior of the chamber is isolated from the exterior of the chamber above the sediment. Soluble contaminants released from the sediment are sorbed onto the surface of a sorbent material disposed within a plurality of semipermeable membrane bags disposed within the chamber. Each semipermeable membrane bag is removed from the chamber in a pre-defined sequence over a period of time and the sorbent material in each bag is analyzed to determine an amount of the soluble contaminant sorbed by the sorbent material. From the results of the analyses, the mass of the soluble contaminant removed from the sediment over time can be calculated.

Sediment sampler for in-situ measurement of soluble contaminant flux rates

A method and device for measuring release rates of contaminants in at least one of a fast release mode and a slow release mode in which a volatile liquid sample is introduced into a sealed transparent reactor vessel having at least one sorbent contained within the transparent reactor vessel and a separator for preventing direct contact between the at least one adsorbent and the at least one volatile liquid sample in the transparent reactor vessel, whereby substantially zero headspace is maintained within the transparent reactor vessel. At least one solvent soluble constituent present in the at least one volatile liquid sample is passed through the separator, resulting in sorption of the at least one solvent soluble constituent by the at least one sorbent. In accordance with one preferred embodiment, the separator is a dialysis bag contained in the transparent reactor vessel into which the resin is placed. The at least one solvent soluble constituent is then removed from the at least one sorbent through the separator.

Zero headspace extractor and method for determining partitioning and contaminant release rates of volatile and semi-volatile compounds

A method for removing volatile and semi-volatile contaminants from groundwater in which the contaminants are stripped from the groundwater by sparging with an inert carrier gas and the stripped contaminants are transported into a bioactive zone into which at least one gaseous oxidant and at least one nutrient are independently injected, thereby stimulating at least one microbial culture associated with the bioactive zone to remove the stripped contaminants from the bioactive zone. By decoupling the sparging of the groundwater from the introduction of oxidants and nutrient feed gases into the bioventing bioactive zone of the subsurface, the oxygen and nutrient inputs to the bioactive zone can be adjusted (or carbureted) and controlled independently from the hydrocarbon input to the bioactive zone to achieve good kinetic performance in the bioactive zone while avoiding the problems of plugging of groundwater sparging due to biofilm and precipitate formation.

Carbureted bioventing for enhanced control of in-situ bioremediation

A method for in-situ dense non-aqueous phase liquids treatment in which a subsurface source area comprising at least one rapid release contaminant is located and free water removed therefrom. The subsurface source area is then heated to a temperature suitable for extracting the at least one rapid release contaminant from the subsurface source area. The at least one rapid release contaminant is extracted from the subsurface source area, resulting in solidification of the dense non-aqueous phase liquids remaining in the subsurface source area.

In-situ thermochemical solidification of dense non-aqueous phase liquids

A method for identifying and characterizing contaminated sources in a site having contaminated soils and sediments in which vapor pressure is measured at a plurality of subsurface soil sampling locations of the site, which measurements are then mapped, resulting in generation of a subsurface vapor pressure map. Contaminant mobility at the subsurface soil sampling locations having a peak vapor pressure is then determined and contaminants in fast release compartments and slow release compartments in the contaminated soils and sediments identified. Thereafter, the fraction of contaminants in the fast release compartments and the slow release compartments is determined. Calibration of the contaminant-specific vapor pressure with laboratory measurements of the rapid release fraction at each site allows a meaningful and rapid estimation of the spatial location and mass distribution of source areas.

Method for identifying sources of rapidly released contaminants at contaminated sites

A process for in-situ remediation of contaminated soil in which at least one treating agent is introduced into the contaminated soil and transported to an underground in-situ treatment zone of the contaminated soil by a foam-based fluid.

Foam transport process for in-situ remediation of contaminated soils

A non-mixed vertical tower anaerobic digester and anaerobic digestion process provides passive concentration of biodegradable feed solids and microorganisms in an upper portion of a continuous digester volume and effluent withdrawal from the middle to bottom portion of the digester, resulting in increased solids retention times, reduced hydraulic retention times, and enhanced bioconversion efficiency. In addition, due to passive concentration of solids, the non-mixed anaerobic digester accommodates high solids loadings and provides separation of microbial phases within the continuous digester volume to achieve substantially complete bioconversion of biodegradable feedstock components.

Solids concentrating anaerobic digestion process and apparatus

An improved anaerobic digestion process is provided to enhance the methane content of product gas so that no further processing may be required for utilization as high quality, high Btu gas comprising greater than 90 percent methane. Operating conditions of lowered carbon dioxide influent concentration to the methane production digester and operation of the methane production digester under pressurization achieve high conversion efficiency rates and high methane content product gas. The carbon dioxide produced during the anaerobic digestion may be physically and chemically separated and removed thereby reducing the carbon dioxide content of the product gas.

Growing community of inventors

Schaumburg, IL, United States of America

Thomas David Hayes