James M. Symons

H2O2VisUV process for photo-oxidation of waterborne hazardous substances — C1C6 chlorinated hydrocarbons

This paper presents results from the first phase development of the H2O2VisUV process for photo-oxidation of waterborne hazardous substances. The technology is generally applicable to numerous situations requiring removal of hazardous substances from: (a) groundwater; (b) drinking water; (c) chemical process water; (d) leakage contamination; and (e) wastewater. However, the first phase research focused attention on drinking water contaminants. The compounds investigated, C1C6, were: tetrachloromethane, tetrachloroethene, dichloroethane, dichloroethene, trichloroethane, trichloroethene and benzene. Dark (no VisUV) oxidation rates and photo-oxidation rates were determined; the latter rate constants were 104–105 greater than dark reaction values. The VisUV photons produce oxidizing free radicals from H2O2 and H2O, and excited state species or free radicals from the reactant compound. The experimental work was conducted in a photochemical batch stirred tank reactor, with 100 W and 450 W mercury vapor lamps, covering the VisUV range, 578.0-222.4 nm. A mathematical model was used to analyze the results and obtain the rate constants. Also, the rate constants were successfully correlated by a molecular composition structure (MCS) model, which permits estimation of rate constants for other C1C6 chlorinated hydrocarbon compounds.

The determination of total organic halide in water: a comparative study of two instruments.

Abstract Total organic halide (TOX) analyzers are commonly used to measure the amount of dissolved halogenated organic byproducts in disinfected waters. Because of the lack of information on the identity of disinfection byproducts, rigorous testing of the dissolved organic halide (DOX) procedure for method bias is not always possible. This note presents the results of a brief study comparing two commercial TOX analyzers with neutron activation. The purpose was to determine if differential bias exists between the two analyzers, and to determine analyte recovery of adsorbed disinfection byproducts. Disinfection byproducts of aquatic fulvic acid were prepared using the following disinfectants: chlorine, bromine, and monochloramine. Analysis of these samples indicated that the two commercial TOX analyzers gave similar results. Neutron activation analysis suggested that organic chlorine recovery from the activated carbon adsorbent was complete, however results with organic bromine recovery were inconclusive. A...

Use of ultraviolet irradiation and hydrogen peroxide for the control of solvent contamination in small water utilities

The U.S. Environmental Protection Agency has recently regulated several industrial solvents. The treatment technologies available for these contaminants are air stripping or adsorption on granular activated carbon. Both have disadvantages: with air stripping, the off-gases may have to be treated prior to discharge and granular activated carbon must periodically be thermally reactivated. The process being researched is a combination of oxidation and ultraviolet (UV) irradiation. The oxidant to be investigated is hydrogen peroxide (H2O2). The general concept is that because H2O2 is easy to feed, because UV technology is improving, and because the waters to be treated are low in TOC, the likelihood of unknown oxidant by-products being produced is small, as is the likelihood of fouling of the UV Lamps, and because no waste streams are produced, this would be an attractive treatment possibility for small utilities. Thus far, benzene, 1,2-dichloroethane, 1,1-dichloroethylene, 1,1,1-trichloroethane, trichloroethylene, carbon tetrachloride, and 1,4-dichlorobenzene have been tested at high concentrations in head-space free Teflon® bags in the dark. In addition, benzene, 1,1,1-trichloroethane, trichloroethylene, and carbon tetrachloride have been tested in the presence of UV irradiation with H2O2, and the results compared as follows: Compound Total conversion (mg/L/hour) Factor of improvement with UV irradiation dark reaction UV irradiation Trichloroethylene 0.03 30 1000 Benzene 0.12 60 500 1,1,1-Trichloroethane 0.11 13 120 Carbon Tetrachloride 0.02 5 250 Batch test studies will be completed for several other compounds in future research and all the compounds will also be tested under flow-through conditions.

H2O2/VisUV photo-oxidation process for treatment of waterborne hazardous substances—Reaction mechanism, rate model, and data for tubular flow and flow stirred tank reactors

Abstract This paper presents the chemical reaction engineering development of the H 2 O 2 /VisUV photo-oxidation process for treatment of hazardous waterborne substances, that occur in groundwater, leachates, and industrial wastewater. Reaction results, on benzene (BNZ), dichlorobenzene (DCB), trichloroethene (TCE), trichloroethane (TCA), and carbon tetrachloride (CTC), have been obtained, providing engineering data and models that can be used to size full-scale equipment. A photochemical flow stirred tank reactor (pcfSTR) and a photo-chemical tubular flow reactor (pcTFR) were used in the experimental work. Two experimental discoveries were made in the course of the work: (1) conventional thermal kinetics do not apply, the rate controlling variable is the photon flux, and (2) for the photo-chemical reactors used, the pcfSTR was more effective than the pcTFR. The following sub-topics are discussed: reaction mechanism, reactor hydrodynamics, photon flux effects, typical reaction data (on benzene and trichloroethane), and rate constants.

The History of Environmental Research in Cincinnati, Ohio: (From the U.S. Public Health Service to the U.S. Environmental Protection Agency)

A 1982 audiotape interview of Gordon G. Robeck, Director of the EPA Drinking Water Research Division in Cincinnati, conducted by James M. Symons (with the EPA in 1982) provided much of the following historical information. The PHS Drinking Water Standards began with the 1893 Interstate Quarantine Act under Treasury because of inspection of immigrants for disease. The 1912 PHS law included funds for establishment of a field Ohio R. unit to determine how stream pollution by waterborne diseases (typhoid fever and cholera) was endangering drinking water supplies. The Field Investigation Station (FIS) was located in the former Kilgour Mansion and in a PHS Marine Hospital in Cincinnati, converted for water research. At the Field Investigation Station, Ohio River water was pumped to a pilot plant for studies on water treatment and on septic tanks. The 1913-1914 Drinking Water Standards for Interstate Carrier Water Supplies preceded the 1925 Streeter and Phelps equations for Ohio R. dissolved oxygen levels. Research started on the effectiveness of sand filtration and chlorination for the protection of public health. In 1953, when the Department of Health, Education, and Welfare (HEW) was created, the PHS was included. In 1954, the water laboratory in Cincinnati moved out to Columbia Parkway to the newly constructed Robert A. Taft Sanitary Engineering Center, consolidating PHS offices from seven locations. Engineering and treatment studies received funding from the Navy and Civil Defense to counteract the possible sabotage of drinking water with planned treatment. The Cincinnati water lab moved administratively through federal changes from 1965 to 1970. In 1965, the Federal Water Quality Administration was formed, and in 1966 the pollution control staff (both civil service and Corps) was transferred to the Department of Interior. Starting in 1967, the PHS began rebuilding drinking water research. EPA, created in 1970, took over environmental programs among various federal agencies. The Federal Water Pollution Control Act of 1972 (commonly called The Clean Water Act) led to the EPAs National Pollutant Discharge Elimination System, which controls discharges and construction grants. Funding under the Safe Drinking Water Act of 1974 led to research that supported drinking water regulations. At EWRI 2013, the Cincinnati Field Investigation Station Centennial will be held (1913-2013).

Influence of Natural Organic Matter on Oxidation of Volatile Organic Compounds by the H2O2/VisUV Process

Abstract This paper presents experimental research to determine the affect of background natural organic material (NOM) on the conversion of five (5) VOCs: 1,1,1-trichloroethane (TCA), benzene (BNZ), trichloroethylene (TCE), 1,4-dichlorobenzene (DCB), and tetrachloroethylene (PCE). Experiments were conducted using DI water and Houston tap water ([TOC] = 3.6 mg/L) as solvents. In addition, the affects of buffer form and excess hydrogen peroxide were determined. Experimental runs were conducted in a photochemical-flow-stirred-tank reactor (pcfSTR), using a 450 W visible/ultraviolet radiation source. The data were analyzed using the Prengle- Shimoda reaction rate model, yielding the reaction rate constant ka (μmols A conv/min, Lr, photon flux) for comparison purposes. Analysis of the experimental data indicated the following conclusions: 1) At the concentrations used for bicarbonate or phosphate buffer, little or no affect was observed; 2) The presence of NOM surpressed the reaction rate for three of the compounds, TCA, BNZ, and PCE at the 95 % confidence level; and 3) Excess hydrogen peroxide, beyond the stoichiometric value, increased the reaction rate constant for all five compounds. The greatest increase was seen for DCB.