Tag Archives: Environmental engineering

Amusing Monday: Animations describe stormwater problems

Contaminated stormwater has been identified as the greatest threat to Puget Sound water quality, and state and federal governments are addressing the stormwater problem in numerous ways.

The animated videos on this page are part of an educational program established as part of the “Puget Sound Starts Here” outreach. This past summer, these videos were posted on YouTube as part of a school curriculum called “Drain Rangers.”

I spotted the videos this past week while working on a blog post about how well local governments in the Puget Sound region are embracing stormwater regulations mandated by state and federal permits. See “Stormwater Report …,” Water Ways, Dec. 15.

The first video on this page is a general introduction to the stormwater problem, based on the idea that it takes 15 minutes for pollution to reach a river. Two videos in the series are similar, although one includes more solutions. I’ve chosen the longer one, called “Video Two.” The third video discusses some basic solutions, while the last goes into more advanced treatments. Others can be found on the Drain Rangers Channel on YouTube.

The story of how “Drain Rangers” became a full-fledged elementary school curriculum is explained in a paper written by Pacific Education Institute (PDF 15.1 mb). Outlines of the school programs can be found on the Puget Sound Starts Here website.

“Polluted stormwater runoff is one of many environmental problems our students will face,” the paper states. “By equipping our students at a young age with the problem-solving tools of the engineer and the verbal and written skills of an effective communicator, we are preparing these students to solve the difficult and challenging environmental issues that affect our present and our future.”

The lessons are designed to meet state requirements for science, literacy and other educational standards. The curriculum addresses the problem of pollution as well as solutions.

“This curriculum introduces students to a problem-solving model where they think like an engineer and explore ways to solve the problem of polluted stormwater runoff,” according to the final report (PDF 965 kb) on the project funded by the Washington Department of Ecology.

According to the report, the grant project produced 15 teacher trainings, pilot projects in nine schools, four videos, six illustrations, 13 facts sheets and five posters. At least 34 schools signed up to implement the curriculum during the current school year, with about 70 schools expected to participate in 2018-19.

Specialized bacteria can remove rogue drugs during sewage treatment

UPDATE, March 10, 2016
I’ve added links for three previous reports related to the degradation of pharmaceuticals and personal care products.
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Concerns are growing about medications and person-care products that pass through sewage-treatment plants and into Puget Sound, where the chemicals can alter the physiology and behavior of fish and other organisms.

Almost everywhere scientists have looked, they have found drugs that people have either flushed down the drain or passed through their bodies. Either way, many active pharmaceutical compounds are ending up in the sewage at low levels. Conventional sewage-treatment plants can break down up to 90 percent or more of some compounds, but others pass through unaltered.

Now, researchers are working on a process that would use specialized bacteria to break down pharmaceutical compounds at existing sewage-treatment plants. The idea, developed by researchers at the University of Washington, is ready for a limited pilot project at one of the treatment plants in the Puget Sound region.

Heidi Gough, left, and Nicolette Zhou with a table-top treatment plant in the lab. UW photo
Heidi Gough, left, and Nicolette Zhou with a table-top sewage-treatment plant in the lab.
UW photo

Studies into this issue began more than 20 years ago, when it became clear that all sorts of compounds were passing through sewage-treatment plants and getting into the environment. Among the early findings was that male fish exposed to artificial birth-control hormones were changing into female fish. Later studies showed that common antidepressant medications seemed to be changing the behavior of fish, making them easier targets for predators.

In addition to estrogens and antidepressants, researchers have found blood thinners, cholesterol-reducing drugs, various heart medications, several hormones and painkillers, along with caffeine, cocaine and various cosmetic and cleansing chemicals.

A study funded by the Environmental Protection Agency looked for 56 active pharmaceutical compounds in sewage effluent from 50 major treatment plants around the country, finding significant levels of many compounds.

A new study by NOAA’s Northwest Fisheries Science Center and the University of Washington looked at 150 compounds coming from two sewage treatment plants in Puget Sound. They were Bremerton’s plant on Sinclair Inlet and Tacoma’s plant on Commencement Bay. They also tested the local waters along with juvenile chinook salmon and Pacific staghorn sculpin to see if the fish were picking up the compounds.

According to a NOAA news release, the study “found some of the nation’s highest concentrations of these chemical compounds and detected many in fish at concentrations that may affect their growth or behavior.” For additional reporting on that study, check out the Kitsap Sun story by Tristan Baurick and the Seattle Times story by Lynda Mapes.

These chemicals could be having effects on various animals in the food web — from benthic organisms that live in the sediments to marine mammals — but more study is needed. Complicating the situation is that multiple pharmaceutical chemicals may work together to create different effects, depending on their concentrations and the affected organism.

Many people would argue that we have enough information to dramatically increase our efforts to remove these compounds from wastewater going into Puget Sound. Drug take-back programs have been started in many cities and counties throughout Puget Sound to encourage people not to flush unused pills down the toilet or drain. See the Take Back Your Meds website. Still, Washington state has yet to develop a comprehensive statewide program that would cover everyone.

Meanwhile, nobody can say what percentage of the drugs going into the treatment plants were dumped down the drain versus being excreted from the human body. But it wouldn’t matter as much if the chemicals could be eliminated at the sewage-treatment plant.

More than a decade ago, Heidi Gough of the UW’s Department of Civil & Environmental Engineering began working on the development of bacteria that could break down these chemicals of concern. She and her colleagues have isolated cultures of bacteria that can break down triclosan, an antimicrobial; bisphenol A, a plasticizer; ibuprofen, an anti-inflammatory drug; 17β-estradiol, a natural hormone; and gemifibrozil, a cholesterol-lowering drug.

The process of isolating helpful bacteria and boosting their numbers could theoretically be used to break down almost any chemical of concern. To be suitable, the bacteria must 1) break down the target chemical to a very low level, 2) grow well in common growth media without the target chemical, 3) break down the chemical even when other nutrient sources are abundant, and 4) work quickly within the normal rate of sewage treatment.

Nicolette Zhou, a former UW graduate student, worked with Heidi to successfully develop a bench-top treatment plant to test the process. Nicolette also produced a computer model of how the operation would perform at a large-scale treatment plant. She completed her analysis and received her doctorate degree last fall. Her latest findings are now awaiting publication in a scientific journal.

Previous reports:

  • Genes involved in Bisphenol A degradation, Environmental Science and Technology.
  • Degradation of triclosan and bisphenol A by five bacteria, Pub Med.
  • Cultivation and characterization of bacteria capable of degrading pharmaceutical and personal care products, Pub Med.

Other systems have been proposed for breaking down complex pharmaceuticals, such as advanced oxidation or other chemical or physical treatment. But biological breakdown offers the most hope in the short term, because it is how most sewage-treatment plants work can be implemented quickly without major modifications and appears to be economical on a large scale, Nocolette told me.

In a large-scale system, the first step would be to identify the specific contaminants to be reduced and then select the bacteria. Some bacteria will break down multiple chemicals, she said.

The bacteria would be grown in a tank and be fed into the sewage digesters reactors, preferably in a continual flow. Multiple chemicals of concern might require several tanks for growing different bactieria.

If the process is successful and adopted by many treatment plants, an alternative process could be developed. Instead of growing the bacteria onsite, where conditions could be difficult to control, all sorts of bacteria could be grown in an industrial facility. The industrial plant would isolate the actual enzymes needed to break down the chemicals and ship them to the treatment plants. The enzymes could be stored and fed into the treatment process as needed.

The research into this treatment process has progressed to where the next step is a small-scale pilot project at a sewage-treatment plant in the Puget Sound area, Nicolette said. A portion of the actual wastewater would be diverted to the pilot plant, where sewage would be subjected to the specialized bacteria and tested for the level of treatment.

Ultimately, more studies are needed to establish a safe concentration for the various chemicals that come from pharmaceuticals and personal-care products. That way, one could culture the appropriate bacteria and establish a reasonable effluent limit for chemicals going into Puget Sound.

Following the money into raw sewage overflows

Water-quality leaders in the Washington Department of Ecology and U.S. Environmental Protection Agency were quick to respond yesterday to a Seattle Times’ story, which begins:

“Seattle and King County are poised to spend more than $1.3 billion of ratepayer money on pollution-cleanup programs that won’t even move the water-quality needle in Puget Sound.”

Yesterday’s story, by reporter Linda Mapes, is about combined sewage overflows — something that Bremerton knows a little about, having completed a cleanup program after 20 years and $50 million in expenditures. See my story from May 30 in the Kitsap Sun.

The premise of Linda’s story is that it might be better for local governments to focus on reducing stormwater overall rather trying to meet a 1988 state pollution standard focused on raw sewage discharges. After all, the reasoning goes, stormwater containing toxic chemicals may be worse for Puget Sound than stormwater mixed with sewage.

The state requirement, by the way, limits discharges of raw sewage in stormwater to one overflow per year, on average, for each outfall pipe.

There is plenty of room for disagreement, as the Times’ story points out. Christie True, director of King County Natural Resources and Parks, stresses that upcoming CSO projects will reduce the public’s exposure to untreated sewage. But Larry Phillips, a member of the King County Council, says dollars spent on CSO projects can’t be spent on buying habitat or attacking the surface-runoff problem, which the Puget Sound Partnership has deemed the region’s top priority.

Bill Ruckelshaus, the first administrator of the EPA and former chairman of the Puget Sound Partnership’s Leadership Council, was quoted as saying:

“This is just crazy; we don’t have unlimited funds in this country, and whatever we do, we ought to spend where we get the most bang for the buck … Cost-benefit has not been part of the discussion.”

David Dicks, former executive director of the partnership and now a member of the Leadership Council, said this:

“It’s just momentum. And what you learn in these things is you can go in and scream and yell and be a revolutionary for a while, but the institutional momentum of these laws has a lot of power, and it is just dumb power. … What we need to do is turn off the autopilot and see what makes sense here.”

Ecology and EPA officials took a stand in favor of the existing rules for reducing sewage discharges. Both issued quick responses to the Seattle Times article, writing on a blog called ECOconnect

From Kelly Susewind, manager of Ecology’s Water Quality Program:

“Infrastructure investments are needed to address water pollution caused by both CSO and stormwater discharges. In areas served by combined systems, CSO projects provide solutions to both CSO and stormwater pollution.

“The investments ratepayers make in their communities’ CSO programs protect public health and Washington’s waters, two principal missions of sewer and stormwater utilities. The success of these projects advances the goals of our state and federal laws to protect, clean up and preserve our waters for present and future generations.”

Adds Dennis McLerran, EPA’s regional administrator:

“Discharging large amounts of raw sewage to Puget Sound and Lake Washington is simply not acceptable. That’s why EPA has worked closely with the state, King County and Seattle over many years to address sewage treatment and the ongoing problem of Combined Sewer Overflow (CSO) pollution. With that work nearly completed, now is not the time to lose our resolve to finish the job visionary leaders in the Puget Sound region started some 40 years ago.”

Cost versus benefits for Bremerton CSO project (click to enlarge)
Kitsap Sun graphic

Shellfish were not mentioned in this discussion — maybe because it was focused on Seattle and King County, where industrial pollution is a major problem. In Kitsap County, shellfish are worth millions of dollars a year to the local and regional economy. For Dyes Inlet, the reopening of shellfish beds probably would not have happened except for a lawsuit that forced the city of Bremerton to comply with the federal Clean Water Act on a strict time schedule.

Lisa Stiffler, former PI reporter who now works for Sightline Institute, discussed Bremerton’s accomplishment with a focus on the cost. See “How Bremerton cleaned its waters, and came to wonder about the costs” in the online publication Crosscut.

A case can be made that shellfish beds in Dyes Inlet could have been cleaned up enough to be reopened by spending just the first $33 million, thereby saving the extra $17 million that it took to bring the city into full compliance with federal law.

But state and county health officials have told me on many occasions that Bremerton and Kitsap County, along with local residents, must continue to work hard to keep the Dyes Inlet shellfish beds open. Beaches in the inlet remain on the verge of closure again, and population growth tends to exacerbate the bacterial pollution.

Kitsap County Health District is respected for its monitoring and pollution-fighting program, but it does help to know that release of raw sewage into the inlet has become a very rare event.

Lisa makes a good point when she says Bremerton would have saved money if engineers would have known more about low-impact development during the planning for CSO reductions. Infiltrating rain water near the source (preferably before it runs off the property) reduces the need to deal with stormwater flowing through pipes. Keeping stormwater out of sewer lines by using LID techniques effectively allows the pipes to carry all the sewage to the treatment plants, even during heavy rains.

Bremerton has become a leader in LID. If city officials had known 20 years ago what they know today, they probably would have spent more on pervious pavement and rain gardens and less on expensive piping networks. But it appears they did their best with the knowledge they had — and LID has become a major part of ongoing efforts to address stormwater.

Cities still working on CSO problems may find Bremerton’s experience helpful. Keeping stormwater out of pipes is proving effective, whether or not those pipes also contain sewage.