Grease is the word as city aims to cut risks to pipes

November 30, 2010

By Warren Kagarise

Fatty byproducts damage city sewer system and reduce capacity

Grease is more than just a word for city engineers.

The byproduct from french fries and other fatty fare can cause the same problems in municipal sewer systems as in human arteries.

The city is scheduled to consider a plan to cut down on the amount of food grease running down restaurant drains and into the municipal sewer system. City Council members could consider a measure as early as Dec. 6 to require offenders and incoming restaurants and other food sellers to install equipment — such as grease interceptors and traps — to prevent the lardy leftovers from reaching the sewer.City Environmental Science Associate Dana Zlateff said blockages caused by fats, oils and grease can cause sewer backups and overflows, plus damage to buildings and property.

“It clogs like an artery,” she said. “It gets constricted — and builds up and builds up and builds up — and then that’s where you get a blockage and a lot of damage.”

Most nearby cities use similar requirements to comply with King County Wastewater Treatment Division rules.

Seattle, Bellevue and other municipalities also adopted measures in recent years to address fats, oils and grease. The neighboring Sammamish Plateau Water and Sewer District — the utility provider and regulator for northern Issaquah customers — also has rules to address the pipe-clogging substances.

The solution: grease-control devices. The proposed Issaquah ordinance calls for installation if a business is known to cause a grease buildup in the sewer system, causes a visible sheen of grease in the system or if the owner makes $20,000 or more in improvements to the business.

Zlateff reached out to restaurateurs and the Issaquah Chamber of Commerce to discuss the proposed ordinance. The business community asked if the measure could be implemented in phases, as the city did to roll out a compostable food-packaging ordinance throughout 2010.

Options include equipment to catch the grease at a restaurant or other food purveyor. Zlateff said the best choice is to tackle grease at the source.

The steps can be as simple as wiping grease and fatty residue from pots, pans and utensils; installing sink strainers; and posting signs to alert employees not to pour grease down the drain.

“A lot of fats, oils and grease get built up in the pipe and basically results in a blockage,” Zlateff said. “It either overflows into their business and then it also comes out the door and goes into surface water and becomes a public health issue.”

Inside municipal pipes, the material congeals into a blob and decreases capacity.

Bacteria release a corrosive byproduct as the material is broken down. The resulting damage to the pipes can be pricey to repair. Or the pipes might need to be replaced.

If the material is not discovered in the city pipes and instead reaches the South Treatment Plant in Renton, the gunk must be removed by hand.

“It’s kind of a ripple effect all the way down,” Zlateff said.

The city uses specialized equipment to record video and photos inside municipal pipes. Council Utilities, Technology & Environment Committee members glimpsed grease images at a November meeting.

Councilman Mark Mullet — a Council Utilities, Technology & Environment Committee member — likened the goop to “something you would see in a Freddy Krueger movie.”

Recycle post-feast grease

Turn Thanksgiving post-feast grease into biodiesel — and help prevent a hazard in local sewer systems.

King County has joined General Biodiesel to offer disposal locations for a free and eco-friendly option to dump cooking fats and grease through Dec. 31.

The closest 24/7 disposal site to Issaquah is the Sammamish Safeway, 630 228th Ave. N.E. Find a complete list of disposal sites at the company website.

Warren Kagarise: 392-6434, ext. 234, or Comment at

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