Why cruise ship wastewater helps and hurts Juneau’s sewage treatment utility


Juneau-Douglas Wastewater Treatment Plant outflow pipe sign Gastineau Channel
Signs along the beach behind the Juneau-Douglas Wastewater Treatment Plant indicate where treated wastewater flows into Gastineau Channel on March 18, 2021. Douglas is on the other side of the channel. (Photo by Jeremy Hsieh/KTOO)

The City and Borough of Juneau has agreed to pay $64,000 in fines to state environmental regulators for repeatedly discharging dirty water from its two main sewage treatment plants. They’ve also promised to take steps to clean up the treated water they pipe into the environment, as well what goes down the drain in the first place.

Here’s what went wrong at the downtown plant, and why Juneau can both blame and thank the cruise industry for its contributions.

Raw sewage from downtown Juneau and Douglas gushes through a newer headworks building at a city treatment plant. It’s noisy and doesn’t smell great. A couple of machines continuously dip and pull a series of plates that look like stainless steel cheese graters. They’re screening out bits of trash before a much trickier stage of treatment.

But this plant isn’t just for city sewage. Up to four cruise ships at once can also offload their wastewater into this system. In the last pre-pandemic summer, cruise ships left behind nearly 20 million gallons of wastewater — more than triple the amount from just five years earlier.

Even so, the cruise ships aren’t pushing the plant anywhere close to its capacity limits. At least, not by volume. In the summer in 2019, the plant operated at about a third of its design capacity of 2.8 million gallons per day.

But the wastewater the cruise ships unload with the city is often harder to treat than regular municipal wastewater. Experts the city hired found that surges of “high-strength” cruise ship waste were one likely culprit for most of the violations at the Juneau-Douglas Wastewater Treatment Plant in recent years. Too much partially treated sewage was getting through and being piped into Gastineau Channel.

Juneau wastewater engineer Lori Sowa and wastewater treatment supervisor Randall Brown discuss how wastewater from downtown Juneau, Douglas and cruise ships gets treated at the Juneau-Douglas Wastewater Treatment Plant on March 18, 2021, with KTOO reporter Jeremy Hsieh. (Photo by Paige Sparks/KTOO)

City wastewater engineer Lori Sowa explained why those surges are problematic.

“Most of the treatment that happens here relies on a community of microbes that naturally grow within the wastewater,” she said. “It’s not just one bacteria or one microbe, it’s really a community of microbes that work together to treat the waste,” she said. “And so, just like any biological system, even like, you think about your body — if things change, then you can get sort of out of whack.”

There were two specific pollutants the downtown plant had trouble lowering. One is tracked by how much oxygen microorganisms need to break stuff down in water. If it’s too high, there’s no oxygen left for fish and other marine life. This happens on a much larger scale when agricultural runoff from the Mississippi River watershed causes huge dead zones in the Gulf of Mexico stretching thousands of square miles.

“It basically sucks the all the oxygen, the dissolved oxygen, out of the water,” said Guy Archibald, the staff scientist at the Southeast Alaska Conservation Council. “You know, life just can’t live there.”

Archibald used to be an environmental chemist who worked on wastewater.

“Yeah, Unfortunately, I used to get a lot of these samples in the lab,” he said with a chuckle.

The other pollutant the city repeatedly ran afoul of was total suspended solids. Before you get grossed out, Sowa said in these cases, it’s likely those helpful, poop-eating microbes. They’re supposed to settle out to the bottom of clarifier tanks, leaving clear water to be disinfected with ultraviolet light for discharge.

But if those solids end up out in Gastineau Channel, they can settle out on the seafloor instead and smother the filter feeders, snails, mussels and crab that live there.

“It’s kind of the basis of the food chain,” Archibald said.

At least, that’s the risk. Sowa said it’s unlikely these intermittent violations or the plant’s proper discharges over time would create a noticeable environmental effect in the channel.

Most of the violations at the downtown treatment plant that regulators reviewed happened in the summer of 2017, when a facility upgrade kept the plant from running normally for months.

When the volume of wastewater flowing into the Juneau-Douglas Wastewater Treatment Plant is low, operators can shut down one of the two aeration basins, as pictured here on March 18, 2021. Because of construction for a major plant upgrade in 2017, they were forced to shut one down in the summer of 2017, when cruise ships offloaded tough-to-treat surges of wastewater. (Photo by Paige Sparks/KTOO)

After the upgrade, the system handled the regular flow and surges of cruise ship wastewater better. Discharge violations fell off.

But if cruise ship traffic gets back on its pre-pandemic path, the fully operational plant may still run into problems.

Locals may be tempted to think cruise ship wastewater is nastier because cruise ship passengers are, you know, full of it?

Negin Kamali is a spokesperson for Princess Cruises. She wouldn’t go on tape, but replied to questions over email. Kamali said their ships generally try to unload their lowest-strength wastewater first: the stuff from guestroom showers and sinks, then laundry and lastly from galleys and food prep.

This practice fits with the rate structure in the contracts that the city maintains with the major cruise lines. They pay a base rate according to how much they offload that’s the same as what industrial users in town pay. Unlike industrial users in town, the cruise companies pay more, the nastier their wastewater is.

Cruise lines paid the city $1,153,784 for offloading wastewater in the 2019 season, according to city revenue data. So the $64,000 in fines that ratepayers covered aren’t catastrophic. City Manager Rorie Watt said the cruise ships’ money actually helps regular people in town.

“Taking graywater from cruise ships provided a substantial amount of revenue that allowed us to probably keep, you know, land-based Juneau operators’ rates down, maybe even as much as 3, 4, 5, 6%.”

The contracts do give the city discretion to refuse offload requests. That’s one thing Watt said should have happened more during the summer of 2017. Sowa said when the plant is running smoothly, they don’t need to refuse service.

And the actual sewage from toilets? Kamali said their ships usually hold on to that. They can legally discharge it untreated once they’re 12 nautical miles from land. Or treat it on board and discharge closer to shore under permits similar to the city’s.

In 2020, 30 out of 42 large ships registered with the Alaska Department of Environmental Conservation for wastewater purposes had permits to discharge treated wastewater closer to shore.

Kamali said there’s generally two reasons the company’s ships would offload in Juneau: They’re close to maxing out their storage tanks, or their treatment plants aren’t working properly. She said Juneau is like a safety valve that gives them more flexibility. She said the costs are significant, and offloading doesn’t come with any “distinct economic or environmental advantage” over other disposal options.

Juneau is the only regular cruise ship stop in Alaska that provides this service. The Port of Alaska in Anchorage can, but it doesn’t get many cruise ship visits. Juneau’s city manager said the pros and cons vary from ship to ship, and policies from cruise line to cruise line.

“All the ships have, you know, their own issues, their own systems and some ships, you know, as they’re upgrading their wastewater plants like the service more than others,” Watt said. “Some companies like the service more than others and they just thought it was good policy while in port to connect.”

While cruise ships have had a significant impact on Juneau’s treatment system, most of their wastewater goes elsewhere. Former DEC regulator Ed White analyzed data of all the large ships discharging in Alaska waters in 2018. In his report for the Ocean Conservancy, he found in 2018, only about 4% was offloaded for treatment in Juneau.

To better monitor what the cruise ships are offloading, the city has installed sensors and samplers at the four docks where the big ships tie up. Workers at the plant can see how much is flowing in from each dock and how dirty it is in real time.

A monitor at the Juneau-Douglas Wastewater Treatment Plant shows wastewater flow rates from four ship cruise docks
A monitor at the Juneau-Douglas Wastewater Treatment Plant shows wastewater flow rates from four ship cruise docks on March 18, 2021. The cruise lines contract with the City and Borough of Juneau to offload their wastewater for treatment. (Photo by Paige Sparks/KTOO)

In its agreement with environmental regulators, the city promises to come up with a new strategy to manage cruise ship sewage. That includes new contracts with the cruise lines for 2022 that will require better information about what they’re unloading before they unload it. And possibly more facility upgrades.

Kamali with Princess said the cruise line and its corporate siblings, Holland America and Seabourn, look forward to working with the city on the strategy.

KTOO is doing a deep dive into sewage this week. In the next story, we’ll learn about a very different set of problems that gunked up the Mendenhall Valley treatment plant. 

Jeremy Hsieh

Local News Reporter, KTOO

I dig into questions about the forces and institutions that shape Juneau, big and small, delightful and outrageous. What stirs you up about how Juneau is built and how the city works?

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