Costing hundreds of thousands of dollars for facilities annually, digester cleaning is expensive, time-consuming and nasty business. Usually, each digester at a wastewater treatment plant is budgeted for a two to five year cycle between cleanings. However, many facilities run into digester issues well before the intended time. Trash, rags, hair and debris all collect in digester basins, pumps, heat exchangers and pipes causing the need for unscheduled maintenance in as little as a single month.

While the issue of digester debris can often be tied to ineffective headworks at a plant, it’s not usually enough to justify an intensive headworks revamp on its own. Digester debris calls for a simple, quick and relatively inexpensive fix that doesn’t require a lot of staff intervention or plant modifications. The solution to digester debris is a HUBER Sludge Cleaner STRAINPRESS.

Designed to disrupt plant operations as little as possible, the STRAINPRESS is unrivaled in its installation flexibility. The Sludge Cleaner can be connected to existing pipes and screen sludge, scum or FOG without breaking line pressure. In fact, there are many benefits of using a STRAINPRESS for digester pre-cleaning. Here are the top seven ways that the STRAINPRESS helps with digester debris issues.

1. Decreased foreign material in digesters increases gas production 

Inorganic trash takes up valuable room inside of digesters that can be used for additional organic material to create more gas. Over time this trash can take up significant volume inside the digester decreasing the amount of organic material or the retention time of organic material in a digester. This leads to lower gas production and less energy or money generated from a plant digester.

2. Decreased operational and maintenance costs of damaged or clogged digester equipment 

Material such as fiber, hair and plastics clog pumps and heat exchangers used in the digester process. When pumps clog they use valuable time and resources to unclog and when heat exchangers have buildup of material they lose heat transfer, reducing digester performance and/or requiring more valuable heat as part of the process. 

3. Reduced instances of digester cleanout saves precious time and money plus reduces safety hazards 

Whether performed by an external company or by in-house staff, the time, money, hassle and hazard of cleaning out a digester makes it something to be avoided whenever possible. By stopping inorganic material and trash from ever entering the digester ecosystem, the STRAINPRESS can reduce the need for digester clean out by more than one-third.

In addition to exorbitant cost, digester cleaning also takes time. Most instances of digester cleanout can span a month or more. All that time is lost digester productivity, and it also consumes staff productivity, if done internally, not to mention the health risk involved.  

4. Inexpensive and simpler solution to a complete headworks upgrade 

While the best option is a complete headworks upgrade to reduce trash in a digester, headworks projects are serious undertakings that often require months or years of planning, design and construction. A complete headworks upgrade is often a very expensive investment for a plant, and many times the existing plant structure will not allow for new, finer screens to be installed. 

Without considerable need, it’s a difficult-to-justify project. Smaller equipment that’s quickly and easily installed, like the STRAINPRESS Sludge Cleaner, has the potential to yield outsize benefits relative to the cost to implement. HUBER is ready to provide turnkey designs configured and ready to be installed in your existing plant’s structure.

5. Makes FOG acceptance a breeze to boost digester performance with high-strength waste 

Grease traps are notorious for their ability to trap not just grease but all manner of debris. Once it’s in there, grease can be very difficult to strain because of its sticky and slick consistency. However, FOG has to be processed and is a valuable resource in gas production. The STRAINPRESS allows this resource to be utilized for increased gas production without the downside of additional debris added to the digester.

6. Handles clarifier scum, so you can use this resource for energy and don’t have to pay for disposal 

Scum from clarifiers can be nasty business. Clarifier scum is often skimmed, dewatered and hauled away, but in plants with anaerobic digestion, scum can be added back into the digester for increased digester performance. The only drawback of adding scum to the digester mix is that scum often has other floating debris that isn't good for the digester including rags and plastics. The STRAINPRESS is a simple process to remove these debris and allow scum to be utilized in the digester.

7. Automation means increased productivity and safety compared to other technologies 

With plant budgets for operational staff being continuously cut, equipment is required that can run automatically. Manual screening equipment is a good short term solution for garbage getting into plant flow, but over the long term, manual solutions create their own issues. In addition to being a drag on productive operations, manual straining solutions can be pretty hazardous and downright disgusting. From sharp materials that can cut through gloves to disgusting and difficult to grasp rags, manual screens are a hard sell for the people who will have to clean them out.

The reduction in safety hazards from even one digester cleaning that’s been avoided is often enough to justify a STRAINPRESS installation. Combine this with the cost savings over time from reduced frequency of maintenance makes a STRAINPRESS a no-brainer. This sludge cleaner is simple to install, easy to start up, and a dream to operate. Because of the built-in automation features, this sludge cleaner adjusts to the material it’s fed automatically as it runs unattended. And because of its clever, enclosed design, STRAINPRESS minimizes odor and can handle even the most difficult materials like scum and FOG. However, don’t take HUBER’s word for it, just ask customers who have installed it!

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HUBER Technology Inc., based in Denver, North Carolina, is one of the country’s largest manufacturers of wastewater, sludge and grit handling equipment. HUBER offers multiple screening and filtration solutions for municipalities and numerous industrial wastewater and intake applications. For more information on any of HUBER’s product lines, please complete the form at www.AskHUBER.com

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