By Patrick Crow
The outbreak of Ebola in western Africa, augmented by a few cases in the U.S. and other nations, has triggered concerns about worker safety at U.S. wastewater plants.
To address those fears, the U.S. Centers for Disease Control and Prevention (CDC) was preparing Ebola guidance for personnel at wastewater treatment plants. Although such facilities are designed to kill viruses and bacteria with ozone, chlorine and ammonia, workers exposed to raw sewage aren't necessarily free from all risks.
In a recent conference call with the American Water Works Association (AWWA) and other water organizations, CDC said it has drafted an interim guidance, which it was circulating for expedited internal review, on precautions to protect wastewater workers from Ebola and how wastewater treatment processes actually inactivate the Ebola virus.
The guidance, Interim Guidance for Workers Handling Untreated Sewage from Ebola Cases in the United States, will outline recommendations for basic hygiene practices and personal protective equipment (PPE) use and disposal.
CDC said the document will provide instructions and protocols not only for employees who perform sewer maintenance, but also for construction workers who repair or replace live sewers, plumbers, and workers who clean portable toilets.
AWWA (which observed that Ebola protocols were appearing almost daily in the public health sector) scheduled its own webinar for members on risks and precautions for drinking water and wastewater employees.
The webinar was designed to present expert perspectives on current Ebola research relating to drinking water and wastewater operations, plus principles for pandemic planning that could be part of an all-hazard risk management plan.
The Water Environment Federation (WEF) also planned a webinar to provide an overview of the survival of Ebola in wastewater and to stress the protective practices wastewater workers should follow.
Meanwhile, the Water Research Foundation (WRF) released a statement reassuring water utility employees that Ebola is actually not a waterborne illness.
"Ebola is not a foodborne, waterborne or airborne illness. The virus is transmitted to humans from wild animals and spreads in the human population through human-to-human transmission," WRF noted. "Ebola is transmitted through direct contact with infected bodily fluids (e.g., blood, vomit, feces). The Ebola virus can only replicate within host cells. Therefore, it cannot survive long in water because it does not have its host -- either a human or an animal.
"Because of Ebola's fragility when separated from its host, bodily fluids flushed by an infected person would not contaminate the water supply," it said. "Researchers believe Ebola survives in water for only a matter of minutes. This is because water does not provide the same environment as our bodily fluids, which have higher salt concentrations. Once in water, the host cell will take in water in an attempt to equalize the osmotic pressure, causing the cells to swell and burst, thus killing the virus."
Jill Thiare, WRF director of marketing and communications, said that WRF stands by those statements but is now directing all inquiries to CDC. She explained that new data about the disease is emerging daily, and as the lead federal agency for Ebola containment and prevention, CDC can provide the best information.
However, there were lingering concerns about the dangers for wastewater workers. For example, some internet postings questioned if Atlanta's sewage system had been compromised because Emory University Hospital has treated Ebola patients.
The Ohio Environmental Protection Agency has also warned wastewater treatment plant workers to carefully follow all Occupational Safety and Health Administration requirements related to exposure to bloodborne pathogens.
Participating in a CDC blog, Steve Silverbush wrote, "As a person that runs a large metropolitan wastewater plant, I do have concerns that have yet to be answered. Those of us in the industry understand that there are diseases that can be carried in wastewater, cholera, hepatitis, and typhoid being the main ones that we have to be concerned with. Most other diseases can't survive temperatures below 85°F.
"My questions are at what temperature does Ebola become inactive, does it become dormant, or does it die? Can it remain active or become airborne from turbulence within the waste stream? Can it be killed with chlorine and at what concentration? I would really like some information on this so as to protect my staff and the public of my city."
About the Author: Patrick Crow covered the U.S. Congress and federal agencies for 21 years as a reporter for industry magazines. He has reported on water issues for the past 15 years. Crow is now a Houston, Texas-based freelance writer.
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