City’s Sewer Lagoon dredging project makes progress

Dredge with giant auger sits in lagoon preparing to suck material from the bottom and send it through the hose to the sludge tank. Backhoe present to lift equipment in and out of lagoon. Two Merrell Bros. employees use a skiff to shuttle back and forth from the dredge and dry land. Photo courtesy of John Sargent/City of Bethel

by John Sargent

The City of Bethel is making progress on its Sewer Lagoon Rehabilitation Project, which entails dredging the primary lagoon cell and repairing the sheet pile jetty. This article tells the dredging story.
It took the City two years to line up grant funding, six months to hire an engineer firm, three months to design the project, and that left a mere two months at the end of summer to get the dredging work done. The City knew it was would take a large, highly trained, professional company to undertake the Bethel project, let alone succeed and complete the work on-time. Then came Merrell Bros., Inc., a biosolids management company out of Kokomo, Indiana.
The City received two responses to its Request for Proposals that it used to hire a dredging contractor. Merrell Bros. received the highest score in terms of quality and pricing after a three-member employee team reviewed the proposals. The Bethel City Council approved the contract on July 25, 2017 for Merrell to remove 2,792 dry tons, or what would amount to 422 truckloads at a cost of $4,353,536.
Merrell Bros. was quick to put the dredge, mixing tank, belt presses, hoses, piping, generator, and other equipment on 18-wheelers in Indiana and direct them to Seattle. The equipment was able to make the July 31 deadline for the Alaska Marine Lines, Inc. sailing, which arrived in Bethel at the end of August. That left two months before it would likely be too cold to operate.
It took a few days to unload the barge, a few more days to get the equipment to the lagoon site, and a week or so to get the equipment situated. “They kept getting stuck,” said Public Works Director Bill Arnold, referring to the challenge Merrell had positioning its heavy equipment in Bethel’s soft sand and tundra. Finally, the Public Works’ crew helped Merrell firmly plant the mix tank, belt filter presses, control room, and polymer mix tank. Subcontractor STG used their 85-ton crane to put the dredge into the lagoon. Hoses and piping were connected.
It took another day or two for the Lower 48 crew to work the bugs out and get in sync with their new environment. On September 13, 2017, Merrell recorded removing 13.52 dry tons of material from the lagoon. From this day forward, the six-member crew worked 24 hours a day, six days a week, to pull out 150 to 280 dry tons of material a day or 24-35 truckloads.
Just when the City breathed a sigh of relief that the project might actually get done on-time, a new problem emerged. Merrell was way ahead of schedule and would be done the first week of October. This was a problem because the CH2M Engineer design called for the removal of 3,000 dry tons of sludge, not the 2,792 specified in the contract, and the City needed to take advantage of the dredge while it was in town and find more project money.
The City scrambled to line up $500,000 of additional funding from the Village Safe Water Program and changed the scope of work so that Merrell could pull out more than 3,000 tons. In the end, Merrell removed 3,411 dry tons of sludge from the lagoon.
“The engineer was surprised to discover that the material contained 40% solids, not the 15% as originally forecast,” said City Manager Peter Williams. “This was due to the amount of sand present in the material, which allowed the contractor to pile it up so high near the lagoon.”
The equipment will stay in Bethel over the winter and Merrell will be back in the spring to install two baffles in the lagoon. The baffles are underwater curtains that direct the flow of wastewater to facilitate decomposition. While the dredging part of the lagoon rehabilitation project will be completed by June 30, 2018, it will take all next summer to construct the new jetty. The jetty is the little peninsula supported by sheet piling that allows evacuation truck drivers to park and empty their truck contents.
Dustin Smith, Chief Business Development Officer for Merrell Bros., said, “Our goal is to under-promise and over-deliver. We faced many challenges on the Bethel project, including meeting the extremely tight timeline, maneuvering our equipment in the soft sand and tundra made worse by all the rain, and the wind flipping our skiff over and swamping it a few times.”
Bethel was the fifth dredging project in Alaska for Merrell Bros. and they are just getting their feet wet.