Gambling with Public Health:
Authorizing Dilution Instead of Sewage Treatment During Rain
Events
What is the draft blending guidance?
- On November 3 EPA released its draft guidance that
relaxes restrictions on discharging inadequately treated sewage into
waterways during rain events. It allows publicly owned treatment works
(POTWs) to divert sewage around secondary treatment units, and then
combine the largely untreated sewage with fully treated wastewater prior
to discharge. Specifically, it authorizes primary solids removal
and disinfection to substitute for biological treatment during wet
weather. EPA is accepting comments on the draft guidance through
January 9, 2004.
Who supports it and why is it being proposed?
- Sewer authorities have convinced the Bush administration
that the answer to insufficient maintenance of aging sewer systems and
capacity problems at some treatment plants during heavy rain is to relax
current treatment requirements under the Clean Water Act. They claim that
abandoning the requirement to treat all sewage will resolve
“inconsistencies in regional enforcement” and avoid the cost of upgrading
treatment facilities.
Why is this a bad idea?
- Blending is bad for public health.
Blended sewage has significantly higher levels of pollution than sewage
that has undergone full secondary treatment. Although solids
removal plus disinfection successfully removes some bacteria, it is not
effective at removing viruses, helminth worms, or parasites.
Viruses and parasites, such as Giardia and Cryptosporidium, cause the
majority of waterborne outbreaks. In contrast, biological treatment
is
very effective at removing viruses and other pathogens from
wastewater. This distinction is critical, because public health
studies have documented that more than half of the waterborne disease
outbreaks in the United States in the past fifty years were preceded by
heavy rainfall.
The Centers for Disease Control estimates
7.1 million cases of mild to moderate and 560,000 cases of moderate to
severe infectious waterborne disease in the United States each
year.
Blending is bad for the environment. Allowing polluters
to discharge inadequately treated sewage into our nation’s waters will
have adverse, long-term environmental consequences. Sewage in our
waterways closes beaches, kills fish, shuts down shellfish beds, and
causes gastrointestinal and respiratory illnesses. In 2000 alone,
sewage contamination caused or contributed to 20% of the 11,270 beach
closings and advisories.
Blending is illegal. The Clean Water Act requires
all wastewater to meet secondary treatment standards prior to
discharge. Blended sewage does not meet current statutory or
regulatory requirements, and EPA has taken several enforcement actions
against sewer operators in which EPA has clearly stated in writing that
blending violates the Clean Water Act.