Does this Digester Recirculation Story Sound Familiar?

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Does this Digester Recirculation Story Sound Familiar?

Until recently, operators and mechanics at Capital Region Water were cleaning out their digester system every day. They had staff on call, and if the system clogged, they would come in and take it apart to clean. With help from Vogelsang, the facility has not only eliminated this need, it has solved a bigger problem as well.

Capital Region Water is a special-purpose unit of local government in Harrisburg, Pennsylvania, that improves, maintains and operates the greater Harrisburg area’s water system and infrastructure “from raindrop to river.” It is the steward for drinking water, wastewater and stormwater services for the City of Harrisburg and portions of surrounding municipalities including Penbrook, Paxtang and Steelton boroughs and Susquehanna, Swatara and Lower Paxton townships.

Capital Region Water called on Envirep, the Vogelsang distributor in the Harrisburg area, for help. The first suggestion Envirep and Vogelsang made was to rework the Vogelsang RotaCut-1000 pump/macerator combined unit with new blades and an XP motor, along with other adjustments. It was also installed in front of the pumps.

After this retrofit was complete, Capital Region fired up the unit to handle the load on their digester recirculation line. The next day was the first time in years they did not have to clean the pumps out. Then they rerouted the flow to an adjacent pump and that pump worked better as well. The digester temps rose and the flow returned to normal. The digester hadn’t been cleaned in 25 years. They had daily pump lock-ups due to the solids that came out of the digester. If they couldn’t recycle the sludge continuously to keep the temperature up around 95 degrees, and temperature gets down to around 88 degrees then the whole digester would go septic. They were delighted to find that the RotaCut had not only kept their pumps clog-free, it cleaned the digester of large solids so thoroughly that even with the RotaCut not in operation, their pumps did not clog. 

The Vogelsang RotaCut was able to clean up Capital Region’s problems because of its outstanding technology.

  • It protected their pumps from clogs and damage
  • Any heavy solids were separated out in the integral rock trap
  • Fibrous materials were sliced up and were unable to clog pumps
  • Relatively maintenance free due to the ACC unit

Cutting vs. shredding

Often, twin-shaft grinders are installed in feed lines going to the digester or recirculation lines. But this can often hinder rather than help the digestion process. One of the most prevalent problems with using a grinder for size reduction is the production of ragging — where solids and fibers that are shredded ball up after they pass through the grinder. This is due to grinders only having the capability to shred, rather than cut, creating stringy inconsistent output, especially when it comes to hair. Along with decreasing digester efficiency, this buildup requires costly cleanings to get things operating again. 

Conversely, the Vogelsang RotaCut macerator produces smaller, more defined, and more consistent particle size with a “scissor-like cut.” This smaller particle size leads to faster and more efficient digestion. The chances of the solids and fibers to ball up after the RotaCut are much less compared to a twin-shafted grinder. This is because a twin-shaft grinder doesn’t really cut any fibers or hair due to the design and mechanics of the technology. With a twin-shaft grinder, there is no contact between blades/rotors. A RotaCut automatically keeps constant pressure between the blades and the cutting screen.

Vogelsang gives you options

Whether you are looking at macerators or twin-shaft grinders, Vogelsang can find the correct solution for your application.

Read more about Vogelsang solids handling units here:


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