Roy C. Haught

Real-time contaminant detection and classification in a drinking water pipe using conventional water quality sensors: techniques and experimental results.

Accurate detection and identification of natural or intentional contamination events in a drinking water pipe is critical to drinking water supply security and health risk management. To use conventional water quality sensors for the purpose, we have explored a real-time event adaptive detection, identification and warning (READiw) methodology and examined it using pilot-scale pipe flow experiments of 11 chemical and biological contaminants each at three concentration levels. The tested contaminants include pesticide and herbicides (aldicarb, glyphosate and dicamba), alkaloids (nicotine and colchicine), E. coli in terrific broth, biological growth media (nutrient broth, terrific broth, tryptic soy broth), and inorganic chemical compounds (mercuric chloride and potassium ferricyanide). First, through adaptive transformation of the sensor outputs, contaminant signals were enhanced and background noise was reduced in time-series plots leading to detection and identification of all simulated contamination events. The improved sensor detection threshold was 0.1% of the background for pH and oxidation-reduction potential (ORP), 0.9% for free chlorine, 1.6% for total chlorine, and 0.9% for chloride. Second, the relative changes calculated from adaptively transformed residual chlorine measurements were quantitatively related to contaminant-chlorine reactivity in drinking water. We have shown that based on these kinetic and chemical differences, the tested contaminants were distinguishable in forensic discrimination diagrams made of adaptively transformed sensor measurements.

Treatability study using Phanerochaete sordida for the bioremediation of DDT contaminated soil

A treatability study was conducted to determine the potential of white rot fungi to remediate soil from a Superfund site that had been contaminated with DDT. A tiered approach was utilized, starting with simple laboratory studies to screen the potential of white rot fungal strains to degrade DDT and culminating with a soil pan study that simulated land farming. Results from early tiers of the study indicated that Phanerochaete sordida had the best potential for remediating the soil. In the soil pan study, the fungus ultimately grew very well after second inoculation. However, the good growth did not translate to higher DDT removal compared to removal in pans that were not inoculated. 14[DDT] fate studies indicated the small amount of removal that did occur for both fungal inoculated and non‐inoculated conditions could be partially attributed to incorporation into humic material. Addition of a surfactant to the soil enhanced the removal of DDT in both inoculated and non‐inoculated soil. Consequently, under...

Adaptive Water Sensor Signal Processing: Experimental Results and Implications for Online Contaminant Warning Systems

A real-time event adaptive detection, identification and warning (READiw) system has two principal functions. First, signal treatment using adaptive algorithms reduces background noise and enhances contaminant signals, leading to accurate detection of water quality changes of as low as 1%. Second, its forensic classification technique relates changes of water quality parameters to the reactivity of contaminants and hereby their chemical classes. To test these detection functionalities, contaminant transport experiments in a pilot-scale single pass pipe were conducted for 16 herbicides and pesticide, inorganic and biological contaminants. Sensor outputs (free and total chlorine, chloride, pH, DO, conductivity, ORP, and turbidity) were analyzed with the adaptive procedures. The results show unique changes of water quality parameters and the reactivity differences among the tested contaminants, based on which an effective READiw system can be configured.

Evaluating a composite cartridge for small system drinking water treatment.

A pilot-scale evaluation was conducted at the U.S. Environmental Protection Agency (EPA) Test & Evaluation (T&E) Facility in Cincinnati, Ohio, on a multi-layer, cartridge-based system that combines physical filtration with carbon adsorption and ultraviolet (UV) light disinfection to serve as a home-base water treatment security device against accidental or intentional contaminant events. The system was challenged with different levels of turbidity, a number of biological contaminants including Bacillus subtilis, Escherichia coli, MS2 bacteriophage and Polystyrene Latex (PSL) beads as a surrogate for Cryptosporidium and a number of chemical contaminants including super-chlorination, methyl tertiary butyl ether (MTBE), water chlorination disinfection byproducts (DBPs) and diazinon. The results demonstrated that the performance of the system varies as a function of the specific contaminant or surrogate. The overall performance indicated the potential of the system to improve the quality and safety of household water and to serve as an additional treatment barrier in circumstances where there is little or no treatment or where the quality of treated water may have deteriorated during distribution. The results also demonstrated that B. subtilis spore can serve as a more conservative surrogate for Cryptosporidium than PSL beads.

Tracer Dispersion Studies for Hydraulic Characterization of Pipes

1. Shaw Environmental, Inc., 5050 Section Avenue, Cincinnati, OH 45212; PH (513) 782-4893; FAX (513) 782-4663; email: Srinivas.Panguluri@shawgrp.com 2. U. S. Environmental Protection Agency, ORD/NRMRL/WSWRD, 26 W. Martin Luther King Drive, Cincinnati, OH 45268; PH (513) 569-7655; FAX (513) 569-7185; email: Yang.Jeff@epa.gov 3. U. S. Environmental Protection Agency, ORD/NRMRL/WSWRD, 26 W. Martin Luther King Drive, Cincinnati, OH 45268; PH (513) 569-7067; FAX (513) 569-7185; email: Haught.Roy@epa.gov 4. RM Clark Consulting Engineer; 9627 Lansford Drive, Cincinnati, OH 45242; PH (513) 891-1641; FAX (513) 891-2753; email: rmclark@fuse.net 5. Shaw Environmental, Inc., 5050 Section Avenue, Cincinnati, OH 45212; PH (513) 782-4730; FAX (513) 782-4663; email: Radha.Krishnan@shawgrp.com 6. Shaw Environmental, Inc., 5050 Section Avenue, Cincinnati, OH 45212; PH (513) 782-4974; FAX (513) 782-4663; email: Don.Schupp@shawgrp.com

Evaluation of Ceramic Filtration for Drinking Water Treatment in Small Systems

There are approximately 50,000 small community systems and 140,000 noncommunity systems serving over 25 million transient and non-transient populations of 3,300 people or less. Several of these small systems are having difficulty complying with the ever increasing number of regulations and regulated contaminants and it is estimated that small systems contribute 74 % of the Safe Drinking Water Act (SDWA) and its Amendments (SDWAA) violations annually. Nearly 90% of these are for Maximum Contaminant Level (MCL) violations. EPA conducts in-house technology development and evaluation to support the small communities. As part of this research effort, EPA has been evaluating a ceramic filtration system for the production of drinking water. The system is being challenged with various turbidity levels, Cryptosporidium (using polystyrene latex beads as a surrogate) and Bacillus Subtilis (to evaluate bacteria removal). This paper presents the results of studies conducted to date on this system. Future research efforts will include testing the system for removal of total coliforms, MS2 bacteriophage and Cryptosporidium parvum.

Predicting Chlorine Residuals in Unlined Metallic Pipes

There are numerous factors that can influence the quality of water in distribution systems. These include chemical and biological quality of source water; effectiveness and efficiency of treatment processes; adequacy of treatment facilities, storage facilities and distribution system; the age, type, design, and maintenance of the distribution network; and quality of treated water. Perhaps one of the most serious public health aspects of water quality deterioration in a network is the loss of disinfectant residual which can weaken the barrier against microbial contamination. A factor frequently cited as contributing to the loss of disinfectant residuals is internal corrosion of the pipe wall material. The effect of velocity in contributing to the loss of residual chlorine has been studied in a simulated distribution and has been reported previously. The results of this research has been verified in studies conducted in full scale systems and is reported in this paper.

Chlorine Decay and DBP Formation under Different Flow Regions in PVC and Ductile Iron Pipes: Preliminary Results on the Role of Flow Velocity and Radial Mass Transfer

A systematic experimental study was conducted using a pilot-scale drinking water distribution system simulator to quantify the effect of hydrodynamics, total organic carbon (TOC), initial disinfectant levels, and pipe materials on chlorine decay and disinfection by-product (DBP) formation. The first phase of the experiments focused on the variables of flow rate and pipe materials and their effects on the formation of trihalomethanes (THMs) a primary category of DBPs in chlorinated drinking water. Different from previously reported bench-scale investigations, this experimental study was to determine chlorine decay and DBP formation kinetics under simulated field conditions and to contrast the effects of new PVC and aged ductile iron pipe materials. In this paper, we report the experimental findings on the rate of THM formation under stagnant, laminar, transitional and turbulent conditions, and further attempt to address the effects of the pipe materials on the reaction kinetics. The results indicate that the second-order DBP formation model of Clark (1998) can sufficiently describe the variations in total trihalomethanes (TTHM) concentrations. The determined reaction constants are smaller under stagnant and turbulent flows in the new PVC pipes than the aged ductile iron pipe. The latter has a high rate of DBP formation accompanying with rapid chlorine residual loss. It is suggested that these observed differences are a result of the mass-transfer enhanced wall demand in the aged ductile iron pipe. Implications for re-chlorination in the distribution network operations are discussed.

Development of a Water Security Filtration System for Whole House Water Supply

The waterborne disease outbreaks have been a constant reminder of the critical importance of ensuring safe drinking water. Properly designed and operated public water systems, either large or small, are required to protect public health. This paper presents the results of tests conducted on a multi-layer cartridge based small system that combines physical filtration with chemical adsorption and ultraviolet light disinfection. The system was challenged with test water containing different levels of turbidity, a number of biological contaminants including B. subtilis, E. coli, MS2 bacteriophage and Polystyrene Latex (PSL) beads (as a surrogate for Cryptosporidium) and a number of chemical contaminants including methyl tert-butyl ether (MTBE), high chlorine concentrations, drinking water treatment disinfection byproducts (DBPs) including trihalomethanes and haloacetic acids, arsenic and diazinon. This paper benchmarks the baseline performance of the system in removing physical, biological and chemical contaminants and identifies the areas for further development. The applicability of the system as a home water security device was evaluated.

Watershed Monitoring Using a Non Line of Sight Data Telemetry System

In collaboration with Clermont County, the U.S. EPAs Office of Research and Development is developing watershed-wide load and transport models to account for stream processes at the Experimental Stream Facility in Milford, Ohio. To better understand environmental stressors in stream flow and the structure and function of stream ecosystems, researchers are establishing continuous water quality monitoring stations along the Lower East Fork River and its tributaries. In conjunction with this effort, EPA and the University of Cincinnati are developing a non-line-of-sight digital datalink using a high frequency radio for telemetry of environmental data with a direct 50-mile range. Features of this design include real-time continuous monitoring of remote sensor measurements, all-weather 30MHz transmission (without repeaters), and solar-powered remote telemetry stations. Remote sensor data is transmitted to a central monitoring station from a network of water quality sensor sites for alarms, analysis, and archiving purposes. Small VHF transceivers can be integrated into the communications network for shorter distance data links where numerous sensors are necessary. Applications include watershed source monitoring, treatment facility data collection, and water storage quality validation.