09/17/2021 Landia France SA
American Falls in Idaho is certainly no stranger to all things water. Almost a century ago, the entire city – nearly 350 residents and their homes, over 60 businesses, churches, schools, power lines – and the entire railroad – had to move to make way for the dam. of American Falls. *
Today, the population of American Falls of 4,300 is served by a sewage treatment plant that is the envy of most small towns in the United States – a facility the cost of which to build. $ 15 million in 2012.
Much of it went well at the municipal four-stage processing plant, which processes 500,000 gallons per day. The only obstacle to secondary treatment and disinfection of domestic and industrial waste before it is discharged into the Snake River has been its submersible mixers. This Idaho facility largely disproves the rather dismissive idea that all mixers are the same.
Despite painstaking issues with the mixers installed during the upgrade to an MBR (Membrane Bioreactor) plant with UV disinfection, the quality of the water released from American Falls was phenomenal. The plant achieves 99.8% BOD and TSS removal, which is crucial for the increasingly popular Snake River fishing waters; a much sought-after paradise for trout, bass and sturgeon.
As site superintendent Scott Dalling frankly comments, “They call us ‘wastewater professionals’ so we better act like that – and we have a $ 15 million treatment plant – so we better do it. take care of it!
Scott and his five colleagues are extremely proud of the current facility, which has come a very long way since the first dual clarifier / trickle filter plant, commissioned in 1963.
“This major investment is something we keep in mind,” added Scott, who worked at the plant for 14 years and became site superintendent in early 2019.
“Our only real lingering problem is with the mixers, which we’ve tried everything with, but they’re under-designed for solids in what should be straightforward anoxic application. “
“A good mix is crucial”
He continued, “We have had constant seal failures which means a lot of downtime. The mixers just couldn’t displace the higher solids concentration we had from the MBR. After many new blenders of the same type, the manufacturer eventually replaced the 10 units with models that were supposed to be better and better, but we always had the exact same issues. A good mix is crucial. We had to try something different.
Goble Sampson, one of the main representatives of manufacturers in the western United States, was approached for help – recommending a mixer from Landia, which was chosen by American Falls for a month-long trial for 24/7 operation.
“We know that Landia pumps and mixers have a long life and reliability,” said Ryan Spanton of Goble Sampson. “And while it wasn’t the hardest job, we wanted to show American Falls what a big difference it would be to having a mixer installed that is really designed to mix sewage sludge. Too often the industry thinks that almost any blender will do, but that just isn’t the case ”.
The test was made faster and easier by the fact that Landia’s mixer could be installed on the existing guide rail. Landia’s ability to use existing masts and brackets saves time and money.
“We saw the transformation straight away,” said Scott Dalling. “Before, the mixers we had were inefficient. The solids weren’t pushed out properly so we had some settling areas and dead spots, as well as some foaming issues, but the newer mixers worked great.
Following the successful trial, three of the ten mixers for the anoxic zones at American Falls have now been replaced with submersible mixers from Landia. Designed with an upper shaft seal system, the mixer propeller is designed for optimum flow / homogenization.
“Much more energy efficient”
“This is an important point for operators,” says Ryan Spanton of Goble Sampson. “It is much more beneficial for customers to provide them with high-quality, durable equipment. In this case, with Landia, not only is the hydraulic efficiency of their mixer much higher, it only draws half the amps, so it is much more energy efficient. It’s also less expensive to maintain and repair, so the savings for homeowners really add up.
Scott Dalling concluded: “Goble Sampson has been a great help – and at Landia we have found some really good, well-built equipment that is much more economical for us in the long run without any breakdowns. Landia mixers are very easy to work with. Everything is simple. As we can secure funding, we will replace all failing mixers with Landia. “
* MMost of the buildings were moved by horses pulling large wheeled carts. On a Sunday in particular, St. John’s Lutheran Church, while in transit, had several worshipers attending their service in the church while it was on wheels!
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