Consultants reveal latest sewer details

CARNATION _ Discussions on whether homes in Carnation

should abandon septic systems for city-wide sewers continued as officials from

the county, city and the sewer consulting firm disclosed more information

on the controversial topic.

American Engineering, the company hired to develop the sewer

plan, originally planned to present their sewer study to the city council at

the end of this month. However, the company is still waiting to hear

comments from government agencies and estimates that the document will be

available by May.

In anticipation of receiving the plan on time, the council has

scheduled a public hearing for May 16, with possible adoption of the plan on

May 30. Both meetings will tentatively be held at 7 p.m. at city hall.

If the council agrees that sewers are necessary for the city, a

workable system could be in place within the next three to five years, said City

Manager Woody Edvalson.

The sewage treatment plant will be located on a 10-acre lot along

West Entwistle Street that is zoned light industrial. The plant will only

utilize half of the property, which will accommodate large concrete basins to

hold the sewage, pumps, filters and a laboratory needed to run the facility.

"Will there be a stench? Absolutely not," said Einar Gundersen of

American Engineering about the concern over smells from the sewage

treatment facility. "There could be odors at times, but offensive? Probably not."

The company is proposing three sewer system methods to the city:

a conventional gravity sewer system, a vacuum sewer system and a

grinder pump system. Most cities have used the gravity system in the past, but

with increased technology, the vacuum and grinder methods have gained in


The gravity system uses angled pipes to transport the sewage from

the homes to the treatment center. This method has the highest

construction costs because the sewer pipes need to be installed about eight to 10 feet

in the ground.

"It creates a lot of commotion with existing streets. And manholes, if

not built right, rain water can go into the [sewer] system," Gundersen said.

However, it is one of the more reliable systems and it generally

costs less to maintain and lasts longer than its mechanical counterparts.

The city will also consider the vacuum sewer system that uses

small pipes that are buried only 30 to 36 inches in the ground _ which makes

it cheaper to install than the conventional system.

The waste is collected into a holding tank on the homeowner's

property that triggers a release valve whenever it gets full. The sewage is then

sucked to the treatment center. If the power goes out, this system would still

be operable because the electronic mechanism is based at the

treatment plant where there is a huge generator for times of emergency.

The grinder pump system, however, would shut down during

power outages because each home would be equipped with its own grinder.

And since it is a piece of machinery, Gundersen said homeowners

should expect some failures.

"It's a mechanical device that will break down at some time," he

said. "Like a water heater, you never really expect something to happen,

but something will happen."

He added that the 6-foot by 30-inch grinder has the capacity to hold

a couple days' worth of sewage in case the power does go out.

Whichever system the Carnation City Council decides on,

Gundersen said all three options are feasible for the city.

"Carnation is flat and tilts to the river which makes any of these

systems workable," he said.

Once the sewage is treated at the plant, the water will then be

discharged into the river or into a holding tank as non-potable water. So

far, several area businesses have shown an interest in purchasing the

reusable water _ which is not adequate for human consumption _ to irrigate

huge tracts of land.

"There will be times of the year where we will use 100 percent for

reuse and times where we'll discharge 100 percent," Gundersen

explained. "In the winter, there is no demand

for the water and no place for storage."

The city's sewer system is expected to be constructed in

three phases, with the downtown core transforming to the new system first

and newer developments joining in about 20 years. At full capacity, the

sewage plant will treat roughly 550,000 gallons of sewage a day.

But some residents questioned why they would need to wait two

decades to have sewers installed into their newly built homes.

Gundersen said that city officials could update

the scheduled phases, but it was assumed that homeowners would probably

not want to fund the new utility.

"The new area has a fairly new septic system that has a good life

and we didn't think you'd want to pay again," he said. "Is there an

urgent need in those areas right now? We don't believe so."

But the greater part of the population in Carnation will be expected

to pay for the sewer project; however, exact figures were not available

yet. Jim Morgan, of the Cosmopolitan Engineering Group, the firm hired

to conduct the financial analysis, described the future customer's

sewer bill as a combination of several factors including the amount of debt

the city must repay for the facility, user fees and the operation and

maintenance costs.

Grants and low-interest bonds would also be available to help the

city finance the sewer system at a fairly reasonable price, Morgan said.

More details about the financial aspects will be available when the city council

discusses the plan next month.

In the meantime, Mayor Bob Patterson will host an open house

from 10 a.m. to noon on Saturday, April 29, to discuss the sewer proposal and

other issues.

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