‘Moola Lagoon’

By: 
Alexis Barker, NLJ News Editor

A much needed biosolids removal project for Newcastle’s sewer lagoons will cost $1.3 million, according to Greg Stumpff, public works supervisor. The City Council awarded the bid to Midwest Injection Inc. in October, the only
contractor to bid on the project. Midwest has previously completed work at the lagoon for the city. 

The need for the lagoon project was first brought to the council’s attention in 2020, according to the NLJ’s Dec. 16, 2020, story, “Sewer lagoon cleanup needed.” At that time, former city engineer Mike Moore told the council that sludge removal was needed, with original estimates for removal totaling only $500,000.

The sewer was upgraded in 1987 after a 1981 Environmental Protection Agency 201 study, a requirement of the Federal Sewage Works Grant under the Clean Water Act, addressed more stringent regulatory requirements for discharging effluent into Little Oil Creek. 

With operation beginning in 1988, the “facultative lagoon” treats wastewater through a biological process — without mechanical processes — according to Moore’s information. 

Before the expansion and upgrades, Newcastle’s treatment facility had only one cell, cell B, currently the largest of its now four cells. According to Stumpff, the city believes that biosolids have been accumulating in cell B since the 1940s. 

The four cells provide not only additional capacity but also the ability to treat the wastewater more effectively. The excess sewer effluent is managed by a combination of evaporation and irrigation. 

The primary cell, A, has a surface area of 16 acres, cell A flows into cell B, which covers 28 acres, then into cell C’s 16 acres and, finally, into cell D’s 20 acres. 

In 2017 and 2018, Moore said, sludge surveys were performed by the U.S. Rural Utilities Service and the estimated amount of sludge was 1 foot in cell A and 7 inches in cell B. Each cell has an operating depth of 5 feet. 

Before preparing to work on cell B, the city had cell A cleaned last year. This is the first time biosolids have been removed from the treatment facility since construction, according to Stumpff. 

“This project has been a long time coming and is a much-needed project. We drained cell B after we filled cell A. Since cell B has been out of service and cell A biosolids were removed, we have seen a drastic change in our discharge-water quality,” Stumpff said. “The sample numbers are back to meeting discharge limits, if we had a discharge permit.” 


 

Background information provided by Stumpff states that biosolid removal is suggested when the cell accumulates more than 10% of its total capacity with biosolids. Over time, organic and inorganic material build up in the cells and begin to cause poor discharge-water quality and will decrease cell capacity. 

“We have noticed for the last few years that our water quality was deteriorating. Since discharge water is land applied, we do not have to meet discharge limits, but we do work towards meeting the same requirements as a discharge permit would require,” Stumpff said. 

Cell B has an average of 20 inches of biosolid depth that needs to be removed, he said.
“It is estimated that we have 64,900 cubic yards of biosolids and an estimated 17,000 tons of biosolids,” Stumpff said. “The contractor (Midwest Injection) will be stockpiling the biosolids at the treatment facility, then they will halt and land apply the biosolids at a later date.” 

Midwest’s total awarded bid is $1,376,000, according to information provided by Stumpff.

Since the 1980s upgrades, Stumpff said, the city has been putting a portion of the sewer bills into a special account earmarked for wastewater treatment facility maintenance and biosolid removal. 

The earmarked account now holds $595,000, according to Stumpff. The city will also use $74,792 from coronavirus relief funds received by the city and $670,750 from a mineral royalties grant for the balance of the cost. 

“The bid came in higher than estimated by $65,000. We were planning to use ARPA funds or use some reserve money to pay for the difference in the estimate versus the actual bid,” Stumpff said. 

The removal of the biosolids is to be completed by Nov. 24, he said. The biosolids will then be hauled and stored until land application can happen at a later date, up to a year after the removal.

News Letter Journal

News Letter Journal
14 W. Main St.
P.O. Box 40
Newcastle, WY 82701
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