David A. Cornwell

University of Florida

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Public Perceptions of Direct Potable Reuse in Four US Cities

American Water Works Association (2015)

Stephanie K.L. Ishii Treavor H. Boyer David A. Cornwell Steve Via

This work is motivated by technical advancements related to direct potable reuse (DPR) and the importance of public values when considering alternative water resources. This study involved the distribution of an online survey to residents in four US cities about existing tap water supplies and “purified water,” defined as “municipal wastewater that has undergone advanced water treatment processes, thus resulting in water quality that, at a minimum, complies with drinking water regulations.” Overall, 50–60% of respondents were in support of using purified water as potable water. Contaminant concerns were highest for taste/smell and microbial contaminants in both current tap water and purified water. Survey results highlight the importance of addressing certain areas when communicating about DPR to the public, such as barriers against microbial contamination, the trustworthiness of utilities, potential improvements over the status quo, and community‐specific drivers that necessitate the use of purified water in a given setting.

Potable water

Tap water

Water source

Water industry

10.5942/jawwa.2015.107.0132

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Citations (21)

Modeling Bromide River Transport and Bromide Impacts on Disinfection Byproducts

American Water Works Association (2018)

David A. Cornwell Baljit K. Sidhu Richard Brown Nancy E. McTigue

Disinfection byproducts (DBPs) formed during potable water treatment can be affected by bromide (Br)‐containing discharges into receiving streams from coal‐fired power plants as well as other sources that increase the bromide content of the source water. This research focused on two aspects related to bromide increases in receiving streams. First, a bromide river transport model was adapted to track bromide concentrations in the river following a point discharge. In this work, the point discharges modeled were coal‐fired power plants. The model tracked the bromide concentrations at river segments after the point of discharge daily and, therefore, at water intakes as a function of time. In this article, the application of the model is illustrated for two rivers: the Ohio River along the Indiana and Kentucky borders and the Dan River in Virginia and North Carolina. Second, models to predict DBP formation due to increased bromide in source waters were developed. The source waters used in the DBP models were obtained from 13 states across the United States. Good model fits were found for predicting trihalomethane as bromide varies, as well as for predicting the unregulated sum of four haloacetic acids (HAA4). A method was also developed to predict the sum of nine HAAs (HAA9) based on measured sum of five HAAs (HAA5; the currently regulated HAAs) and modeled HAA4. The DBP formation models developed using the specific criteria evaluated in this research would have applications beyond only bromide discharges from coal‐fired power plants and would apply to any cause of a bromide increase in the source water.

Haloacetic acids

Trihalomethane

10.1002/awwa.1145

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Citations (7)

Feasibility Studies on Liquid Ion Exchange for Alum Recovery From Water Treatment Plant Sludges

American Water Works Association (1980)

David A. Cornwell Roger M. Lemunyon

In the final article of a three‐part series on the use of liquid ion exchange procedures for aluminum recovery from water treatment plant sludges, a specific procedure for the purification of aluminum prior to recycling is presented. Batch tests were conducted to develop appropriate extraction and stripping equilibrium curves. The study determined that more than 95 percent recovery of soluble aluminum is feasible.

Alum

Stripping (fiber)

Ion-exchange resin

10.1002/j.1551-8833.1980.tb04465.x

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Citations (8)

Using spore removal to monitor plant performance for Cryptosporidium removal

American Water Works Association (2007)

Richard A. Brown David A. Cornwell

Data from available literature indicate that Cryptosporidium oocysts are removed more efficiently than aerobic spore‐forming bacteria during water treatment processes involving clarification and filtration. Therefore, monitoring removal of naturally occurring aerobic spores can provide a conservative estimate of the potential for Cryptosporidium removal in full‐scale water treatment processes, which in turn can be used to establish the demonstration of performance credit allowed by the Long Term 2 Enhanced Surface Water Treatment Rule as well as to provide a valuable performance evaluation tool for water plant operators. The results from this study showed that (1) median raw water spore concentrations ranged from 300 to 3,000 spores/L for two lake sources and 80,000 to 400,000 spores/L for four river sources; (2) median filtered water spore concentrations rarely exceeded 5 spores/L, and these levels of removal were not apparently dependent on source water concentration; and (3) >4‐log spore removal could not be mathematically demonstrated unless raw water levels exceeded 10,000 spores/L (e.g., river sources).

Raw water

Filtration (mathematics)

Bacterial spore

10.1002/j.1551-8833.2007.tb07892.x

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Citations (17)

Evaluating Polymers to Avoid Polymer‐Induced N‐Nitrosodimethylamine Formation

American Water Works Association (2017)

David A. Cornwell Richard A. Brown Stuart W. Krasner

Chloramines are often used instead of free chlorine as a residual disinfectant in order to limit formation of regulated halogen‐substituted disinfection by‐products that form more readily in the presence of free chlorine. However, the use of chloramines can form carcinogenic nitrosamines. Some polymers, particularly polyDADMAC, contribute nitrosamine precursors (as confirmed in this research). Alternative polymers produced from natural products evaluated in bench and pilot testing produced clarification and filtration performance as good as or better than that with polyDADMAC or other currently used polymers while contributing little or no nitrosamine precursors. However, there was indication of high biological growth in filters that were not chlorinated. Replacing readily biodegradable acetic acid with a mineral acid (e.g., hydrochloric acid) during synthesis of chitosan might reduce the potential for biological activity with this polymer. Performance variations in different source waters suggest that site‐specific determination of the best polymer type, dose, and application point should be completed before using any polymer.

Nitrosamine

Disinfectant

Hydrochloric acid

Chloramination

10.5942/jawwa.2017.109.0040

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Citations (7)

Trace Contaminants in Water Treatment Chemicals: Sources and Fate

American Water Works Association (2004)

Richard A. Brown David A. Cornwell Michael J. MacPhee

This article describes a comprehensive national investigation of trace contaminants in water treatment chemicals. In general, no pervasive problems with trace contaminants in US water treatment chemicals were found, but serious isolated contamination incidents continue to occur. The most commonly identified problems were transport‐related, typically the result of improperly cleaned or maintained delivery vehicles and transfer hoses. These and other related problems were routinely averted when utilities developed and implemented inspection and evaluation programs for incoming chemical deliveries. This research produced compositional data from more than 50 treatment‐chemical products. Trace contaminants contributed by coagulants partitioned primarily into residuals rather than finished water during full‐ and pilot‐scale studies conducted during this investigation. Mass balance calculations from these partitioning studies confirmed the compositional data reported for coagulants in this research, results that are much lower than limited data reported previously in the literature for samples collected before 1990.

TRACE (psycholinguistics)

Water contamination

10.1002/j.1551-8833.2004.tb10763.x

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Citations (8)

How Have We Done in Reducing Lead in Water Since the LCR?

American Water Works Association (2018)

David A. Cornwell

With a proposal to update the Lead and Copper Rule expected in 2019, it is a good time to evaluate improvements since the 1991 rule took effect.

Lead (geology)

10.1002/awwa.1167

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Citations (5)

Residuals processing and disposal

American Water Works Association (2000)

David A. Cornwell

10.1002/j.1551-8833.2000.tb08817.x

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Citations (1)

Sludge: The Disposal Dilemma

American Water Works Association (1987)

F. Michael Saunders Peter W. Doe Richard H. Moser Larry Wapensky David A. Cornwell

This discussion took place during the AWWA annual conference June 24, 1986. Participants were: Peter Doe, Havens and Emerson Inc., Saddle Brook, N.J.; Richard H. Moser, American Water Works Service Co., Marlton, N.J.; Terry Rolan, City of Durham, Department of Water Resources, Durham, N.C.; F. Michael Saunders, School of Civil Engineering, Georgia Institute of Technology, Atlanta, Ga.; and Larry Wapensky, RCRA Permits Section, US Environmental Protection Agency, Region VIII, Denver, Colo., David A. Cornwell, Environmental Engineering and Technology, Newport News, Va., served as moderator.

Atlanta

10.1002/j.1551-8833.1987.tb02853.x

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Citations (2)

High-precision Pb isotopes of drinking water lead pipes: Implications for human exposure to industrial Pb in the United States

The Science of The Total Environment (2023)

George D. Kamenov Benjamin F. Swaringen David A. Cornwell Nancy E. McTigue Stephen M. Roberts

Lead (geology)

10.1016/j.scitotenv.2023.162067

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Citations (9)