In 2010 the Pittsburgh (Pa.) Water and Sewer Authority (PWSA) observed a significant increase in the concentration of total trihalomethanes (TTHMs), especially brominated THM species, in its finished water. In an effort to explain these changes, PWSA and the University of Pittsburgh's Swanson School of Engineering investigated bromide concentrations in the Allegheny River (PWSA's source water) and THM formation in PWSA's drinking water. Results of the investigation indicated that elevated bromide concentrations in the source water were associated with increased concentrations of TTHMs, especially brominated THMs, in the drinking water. Additionally, a survey of the river system suggested that industrial wastewater treatment plants (brine plants) treating Marcellus Shale wastewater, as well as other wastewaters, were major contributors of bromide in the raw water. The study results also indicated that PWSA's conventional treatment process, which includes enhanced coagulation and secondary sedimentation, was ineffective at removing bromide from the source water. The increase in bromide concentrations in the Allegheny River system could affect the ability of conventional drinking water plants drawing water from this source to comply with the Stage 2 Disinfectants/Disinfection Byproducts Rule.

In the wake of the ongoing 2014/2015 Ebola virus outbreak, significant questions regarding the appropriate handling of Ebola virus-contaminated liquid waste remain, including the persistence of Ebola virus in wastewater. To address these uncertainties, we evaluated the persistence of Ebola virus spiked in sterilized domestic sewage. The viral titer decreased approximately 99% within the first test day from an initial viral titer of 106 TCID50 mL–1; however, it could not be determined if this initial rapid decrease was due to aggregation or inactivation of the viral particles. The subsequent viral titer decrease was less rapid, and infectious Ebola virus particles persisted for all 8 days of the test. The inactivation constant (k) was determined to be −1.08 (2.1 days for a 90% viral titer decrease). Due to experimental conditions, we believe these results to be an upper bound for Ebola virus persistence in wastewater. Wastewater composition is inherently heterogeneous; subsequently, we caution that interpretation of these results should be made within a holistic assessment, including the effects of wastewater composition, dilution, and potential exposure routes within wastewater infrastructure. While it remains unknown if Ebola virus may be transmitted via wastewater, these data demonstrate a potential exposure route to infectious Ebola virus via wastewater and emphasize the value of a precautionary approach to wastewater handling in an epidemic response.

In March 2014, an outbreak of Ebola virus (Ebola) arose in western Africa. Since then, there have been more than 10000 cases reported with a mortality rate of approximately 70% in clinically confirmed cases. A significant unanswered question has arisen for the scientific and engineering communities, as well as the general public, surrounding Ebola virus persistence in the environment and the potential for an environmental route of Ebola virus exposure. Here, the authors review the state of knowledge of Ebola virus environmental persistence and highlight future research needs. In general, there are limited data on the environmental persistence or disinfection of Ebola virus available in the open literature. The available evidence suggests that Ebola virus is inactivated at a rate more rapid than or comparable to those of typically monitored enteric viruses. Additionally, while environmental exposure is not the dominant exposure route, available data suggest that it is imprudent to dismiss the potential of environmental transmission without further evidence. A significant research effort, including environmental persistence studies and microbial risk assessment, is necessary to inform the safe handling and disposal of Ebola virus-contaminated waste, especially liquid waste in the wastewater collection and treatment system.

Since the events of Sept. 11, 2001, the world has become a different place. More attention than ever is being paid to the nation's vulnerabilities, and this has prompted officials at all levels to examine the tools available for ensuring the security of public utilities. The recent emphasis on making sure that public water supplies are safe has created the need for continuous monitoring systems and analytical techniques that can be used at the utility level to test for a variety of toxic materials in a short amount of time. States and colleagues provide a survey of continuous monitoring and analytical methods currently available to utilities for security purposes. This survey grew out of an investigation the Pittsburgh (Pa.) Water & Sewer Authority (PWSA) and the University of Pittsburgh School of Engineering conducted in order to identify feasible analytical responses to security concerns. This investigation included a literature search; discussions with personnel from various water utilities, water industry organizations, and regulatory agencies; and evaluation of several commercially available monitoring and analytical systems. The article also takes a look at the analytical measures PWSA uses to screen for possible contamination in response to threats or suspected tampering with its water system as well as during times of heightened security. Although these methods are limited and their results should be interpreted with caution, there are some techniques, such as acute toxicity testing, that can be useful.

Current World Health Organization and Centers for Disease Control and Prevention guidance for the disposal of liquid waste from patients undergoing treatment for Ebola virus disease at hospitals in the U.S. is to manage patient excreta as ordinary wastewater without pretreatment. The potential for Ebolavirus transmission via liquid waste discharged into the wastewater environment is currently unknown, however. Possible worker inhalation exposure to Ebolavirus-contaminated aerosols in the sewer continues to be a concern within the wastewater treatment community. In this study, a quantitative microbial risk assessment was carried out to assess a sewer worker's potential risk of developing Ebola virus disease from inhalation exposure when performing standard occupational activities in a sewer line serving a hospital receiving Ebola patients where there is no pretreatment of the waste prior to discharge. Risk projections were estimated for four scenarios that considered the infectivity of viral particles and the degree of worker compliance with personal protective equipment guidelines. Under the least-favorable scenario, the median potential risk of developing Ebola virus disease from inhalation exposure to Ebolavirus-contaminated aerosols in the sewer is approximately 10-5.77 (with a first to third quartile range of 10-7.06 to 10-4.65), a value higher than many risk managers may be willing to accept. Although further data gathering efforts are necessary to improve the precision of the risk projections presented here, the results suggest that the potential risk that sewer workers face when operating in a wastewater collection system downstream from a hospital receiving Ebola patients warrants further attention, and that current authoritative guidance for Ebolavirus liquid waste disposal-to dispose in the sanitary sewer without further treatment-may be insufficiently protective of sewer worker safety.