News from Schwing Bioset

Dewatering with a Screw Press at Upper Sandusky WWTP

 

Written by Eric Wanstrom

 

The city of Upper Sandusky, Ohio, operates a wastewater treatment plant that processes roughly two million gallons per day. The plant had historically aerobically digested their biosolids and dewatered them to approximately 10% dry solids content using drying beds. Due to the age of the drying beds, the hauling costs were continually increasing, which was creating a burden not only in expenses, but also on personnel time to keep the beds functioning.

Upper Sandusky began a search to identify new dewatering methods that could replace the aging drying beds. While exploring several technologies and performing multiple pilot studies to determine the best technology, not only from a performance standpoint, but also considering ease of use and maintenance requirements, screw presses were determined to be the preferred technology. 

Schwing Bioset was invited to run our screw press pilot, which proved quite successful, with cake results exceeding 20% dry solids. Plant staff were also impressed with the quality of construction and the ease of use of the machine.

Schwing Bioset equipment was chosen as the best value and was selected as the basis of design for the new dewatering building. The new FSP603 screw press will produce over 80% dryer cake than old drying beds, reduce the city’s hauling and disposal costs substantially as a result of the increased solids content produced, and reduce the amount of labor required by city staff. 

Schwing Bioset FSP603 Screw Press  Schwing Bioset FSP 603 Screw Press

The Schwing Bioset screw press provides a state-of-the-art solution for wastewater plants and consulting engineers looking to improve their dewatering process. Offering the widest range of model sizes available on the market, our screw presses also come with a wide range of features designed specifically with the wastewater treatment plant operator in mind.

Contact us to learn more about this project or visit here to learn more about our dewatering screw presses.

 

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Tags: Wastewater Treatment, Screw Press, Dewatering

The Maine Solution

 

When an upgrade to the biosolids dewatering component at the Westbrook/Gorham Regional WWTP was needed, a screw press has helped the facility dramatically reduce their sludge hauling/handling costs.

Written by Larry Trojak, Trojak Communications

Version also published in WaterWorld, June 2020

 

Schwing Bioset Dewatering Screw Press

 

When an upgrade to the biosolids dewatering component at the Westbrook/Gorham Regional WWTP was needed, plant personnel looked at several different available technologies. Handling secondary sludge alone is challenging, and after an extensive trial and evaluated bid process, they opted for a screw press from Schwing Bioset, Inc. Today, sludge leaving the plant is averaging just above 20 percent solids, and the Westbrook/Gorham Regional WWTP has dramatically reduced costs associated with hauling and landfilling their material. Are they pleased? To quote the locals: “Ayuh.”

 

Diversity in the District

The Portland, Me., Water District (PWD) manages its wastewater treatment through four facilities: East End, the largest plant in the state, which handles wastewater for the Portland metro and surrounding areas; Westbrook/Gorham Regional WWTP, which serves Westbrook, Gorham and a portion of Windham; Cape Elizabeth, which handles wastewater from 3,100 residents in the southern part of the town of Cape Elizabeth; and Peaks Island, which serves 600 island residents — a number that can swell to more than five times that in the summer tourist season. While the Westbrook/Gorham Regional facility is an extended aeration plant, each of the others utilizes a different technology for dealing with their biosolids, according to Steve Picard, the operations foreperson at the plant.

“Within the District, we are certainly varied in our approaches to wastewater treatment,” he said. “East End is a conventional aeration-type plant using clarifiers; Peaks Island is a sequencing batch reactor facility, and Cape Elizabeth is an oxidation ditch plant — they are all similar in many ways but different in others. The Westbrook/Gorham Regional plant was built in 1978. An upgrade to the plant’s aeration system is planned for later in 2020.”

Picard added that three-quarters of the existing plant will be upgraded — a move that will include the addition of new clarifiers mechanisms, a blower facility, and diffused air-type aeration equipment. To show how things have changed, the original plant’s price tag was $14 million; this modification alone is $10 million.

 

Planning Ahead

About two years prior to the plant upgrade, the Portland Water District saw the sludge disposal costs Westbrook was incurring and committed to improving the plant’s dewatering capability. Up until then, the facility, which is rated for 4.54 MGD but treats an average flow of about 3.2 MGD, took sludge from the bottom of the final clarifiers, pumped it to a gravity belt thickener where it was thickened to approximately 4 percent solids, and sent it to a 2.5 meter belt press.

“On a good day, that belt press would give us maybe 17–18 percent solids,” said Picard. “Unfortunately, because we deal strictly with an inflow of secondary sludge here at Westbrook, there weren’t many of those good days. To make matters worse, because we were sending that sludge to a trailer for transport to a landfill about three hours away, we were paying to haul a lot of water that didn’t need to be there. That had to change.”

For Schwing Bioset, finding out about the project was a classic case of being in the right place at the right time. For nearly 30 years, Westbrook has been using a Schwing Bioset KSP 10 piston pump to move sludge from the belt press out to the trailers — a distance of more than 70 feet. Word that they were actively seeking equipment to enhance their dewatering effort got the attention of a technician who happened to be on site.

“When I mentioned that we were about to go out to bid for dewatering equipment, the tech said that Schwing Bioset also made a screw press that could be a good fit,” said Picard. “He went back, told his people, and they were suddenly in the running for the bid along with several other manufacturers. Their timing couldn’t have been better.”

 

Natural Solution

After extensive testing of four manufacturers’ products and a competitive bid process, PWD selected an FSP 1003 screw press from Schwing Bioset.

“Because we already had the piston pump and power pack from Schwing Bioset, we thought that having a screw press from the same manufacturer — a company that we were already very satisfied with — could only work to our advantage,” said Picard. “However, they also outperformed the others we tested and were within our budget, so we felt confident that we’d made a good decision.”

Features that helped make the case for Westbrook included the unit’s low-speed operation — which enhances its lifespan — and automated control. Ease of regular maintenance was also key, including a split screen casing to simplify access for any maintenance activities such as replacing the sealing lip and eventually the screens. Both items can be replaced without having to remove the screw.

“In addition, because the entire operation is now enclosed, all the odor associated with dewatering is contained,” said Picard. “And finally, we liked the fact that the Bioset press could be cleaned while in use, so the dewatering operation would not be impacted by it. All these played a role in our decision.”

 

Getting the Numbers Up

Once the new press was in place (the installation was completed by the same contractor that handled their belt press 28 years ago), Picard and his team were initially stymied trying to find the polymer that would give them the numbers they were anticipating. Using the same product they ran with the belt press resulted in no change: solids in the 17 percent range.

“We suspected that was because, unlike the screw press, the belt press had little to no agitation to it and it held the floc together easily,” he said. “However, by the time we tested our fourth polymer, we started getting solids numbers up in the 19–20 percent range. Connecting the screw press to the polymer injection system we had used with the belt press — then adding two more injection points — got us a bit closer.”

In addition to polymer optimization, there was a period of learning how the new system could be successfully operated at the plant. Doing minor adjustments to the injection system prior to running the screw press for several days without making any changes allowed workers at the plant to verify what worked and what didn’t.

“We were closely tracking our polymer feed rate and the cake coming out of the system and, when we started to break 20 percent solids, knew we were on to something,” Picard said. “We learned that, where the polymer is injected into the system is hugely important. Here, in an area one level down from the press, the polymer goes into a check valve which gives it a good primary mix with the sludge, then comes up and into a huge reaction tank equipped with a variable speed mixer. Using that configuration, the difference was impressive: the 2.5–3 percent feed rate at which we used to feed the belt press didn’t even tax the screw press. Instead, we found out the screw press runs great at 4–4.5 percent, which was a nice plus for us.”

 

Biosolids  Westbrook Wastewater Treatment Plant

 

The Better Choice

With their tweaks in place, Picard and his team at Westbrook saw a continued uptick to the point where they’ve averaged just over 20 percent solids out of the screw press for just over a year now and have seen that number climb as high as 22.5 percent or 24 percent on some days. That has resulted in a net savings — even with added polymer costs factored in — of about $40,000 annually. To the uninitiated, an increase in solids of up to 5.5 percent might not seem substantial. However, that number still represents a 25 percent increase in performance.

And, said Picard, context is key.

“The difference between the two processes is particularly significant when you remember that we are dealing with a straight secondary sludge which is very hard to dewater,” he said. “Even Schwing Bioset rated the screw press at only 19–20 percent under these conditions.

 

Anticipating Change

Today, Westbrook is producing about 30 tons of a better dewatered product every day they dewater during their five-day-a-week operation. By reducing the amount of water in each load, the three-hour trip to the landfill for disposal is far more cost-effective.

“Disposal for us is a costly operation and the Schwing Bioset press has helped significantly knock down those costs,” said Picard. “In addition, there was a good deal of belt spraying, wash water, etc., associated with the previous process, resulting in a constant mist in the air. The place was continually wet where today, things are clean and dry.

He adds that, throughout this conversion process, PWD leadership was outstanding in working with them — giving them support and encouragement all along the way.

“On that note, when we did the screw press install, we kept the belt press here for a year as a backup in case the Bioset didn’t work,” said Picard. “Eventually that belt press was sold for scrap — I guess that says it all.” 

 

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Tags: Biosolids, Screw Press, Dewatering, Wastewater Treatment Plant

Big Changes at Pine Creek Wastewater Treatment Facility

 

Written by Larry Trojak, Trojak Communications

Version also published in TPO Magazine, February 2020

 

Alabama facility sets lofty goals for its upgrade; meets or exceeds them all.

When the City of Prattville, Alabama, recently chose to upgrade its Pine Creek wastewater treatment facility, it spared no effort in doing so. While they had made smaller, incremental modifications in the past, this time around they took the plant from simply adequate to boldly forward-thinking, designing it to be viable and effective for at least the next quarter century. Included in the wholesale changes was a rethinking of its solids handling capability which, up to that point, was both basic and costly. Today, the Pine Creek Clean Water Facility uses a new approach to aeration, dewaters through a pair of new screw presses, is generating a Class A biosolids for area land application, and is now accepting sludge from a nearby sister facility. In this case, being up a creek is definitely a good thing.

 

Dealing with Growth

Located 20 minutes northwest of Montgomery, Prattville is a city of 34,000 which has seen some impressive development of late. According to the local Chamber of Commerce, between 2014 and 2018 alone, more than 130 new businesses have opened in Prattville and immediate surrounding areas — a total of $760 million in capital investment. All that growth prompted city officials to look at existing infrastructure demands and determine that upgrades to their wastewater treatment effort were in order.

“This was a wholesale overhaul of the entire treatment process to help deal with the growth in the area,” said Greg
Thompson, project engineer with Engineers of the South. “We are a consulting engineering company and have been working with the City for more than 15 years now. So, we were actively involved in the research and planning leading to the upgrade. The original plant, built in 1979 as part of the Clean Water Act, had a 3 mgd capacity. In addition to options for dealing with the anticipated increases in volume, we talked with city officials about re-thinking the entire biosolids treatment and disposal process.”

 

Alabama Dream Sheet

Though a plant-wide change was in the cards, the evaluation criteria for that change were very ordered and specific. According to Dale Gandy, Prattville’s Director of Public Works, the desire to use state of the art technology headed up the list of desirables. 

“Obviously, we wanted to tap into the strengths of today’s newer technology,” he said. “However, we also wanted to try to utilize ‘green’ infrastructure within the plant; had our sights set on looking into a Class A biosolid; wanted to create an effluent that was cleaner than the environment into which it was headed; wanted the whole effort to be energy efficient; and needed the plant to gain an additional 25-30 years of viability. In addition, because we didn’t have unlimited funds to throw at the project, we had to be relatively cost conscious in our efforts. It was a long list to try to meet but we set out confident that it could get done.”

The new plant design that Thompson and his engineering team — working hand in hand with Gandy and Prattville’s
plant management — envisioned, would take the facility from 3.0 to 5.7 mgd — almost doubling in volume. That
increase in capacity, they felt, would give them the 25-30 year life expectancy they needed.

 

Schwing Bioset Screw Presses  Schwing Bioset - Bioset Process Reactor

 

Outdated Concepts

To get to that point, there was not one area of the Pine Creek facility that would be left untouched by the overhaul. Designed in the late 1970s as a conventional activated sludge facility, the plant utilized a coarse screen in a deep sump, prior to the raw sewage pump station, followed by aerated grit removal.

“Aeration in the original design consisted of three parallel basins with two fixed-mounted, low speed surface aerators per basin,” said Thompson. “Control of the aeration system consisted only of locally-mounted low/high-speed selector switches. Not only was the process energy-inefficient, the inability to aerate sufficiently or deal with varying flow rates and oxygen demands led to plant upsets and periodic effluent violations. The warm summer months, when effluent limits are lowest, made it particularly hard for operators to maintain compliance.”

At that time, once biosolids met Class B requirements, they were hauled off to a local field — with 100% of the liquid
— for land application. The facility averaged 10-15 tanker loads of the wet material per day. “But if it had rained and the field was wet, they couldn’t land-apply, so the plant had to be prepared to store material in the digesters,” added Thompson. “It’s not surprising they knew a change was needed.” Finally, the previous clarifiers utilized a mix of organ pipe and scraper blade solids-removal systems. Disinfection, which originally used gaseous chlorine, was updated to UV in a 1999 plant modification.

 

In With the New

Thompson and his group worked hard, not only to address all the issues with the existing design, but also to ensure
the plant’s viability for decades to come. In aeration, to deal with the high ammonia numbers caused by an inability to nitrify, they opted for a VertiCel solution (Evoqua Water Technologies, Pittsburgh, Pa.).

“VertiCel uses a combination of disk aeration followed by fine bubble diffused air,” said Thompson. “In that way, we
felt we could tap the efficiencies of both types of aeration to meet our need for an energy-efficient design and to get full biological nutrient removal.”

Conversely, changes to the plant’s digestion phase included taking them from using surface mechanical aeration to
diffused aeration. “Prattville always had issues getting enough oxygen transfer with the old system,” said Thompson. “This combination of disc aerators and fine bubble diffusers powered by Howden blowers (PD Blowers, Inc, Gainesville, Ga.) is both energy efficient and has great oxygen transfer.” Also covered in the expansion’s design were an all-new headworks, two new fine screens (Duperon, Saginaw, Mich.), and grit removal which incorporated Eutek HeadCell technology and WEMCO Hydrogritters.

 

Road Trip

With preliminary design considerations in place, representatives from both the City and Engineers of the
South, visited a number of wastewater treatment plants throughout the southeast U.S. to review various approaches
to dealing with biosolids. One of the things driving the city’s decision to create a Class A biosolid product was, again, growth in the area.

“We were seeing new industries coming in regularly and knew that we could soon be running out of industrial fields
like the one on which we’d been applying,” said Sam Russell, Pine Creek’s former plant manager who was brought on as a consultant during the upgrade. “So, we knew solids handling had to change and that dewatering would be a huge part of that discussion."

Evaluations of available dewatering options included visits to a half dozen facilities to view belt presses, screw presses and centrifuges, and conversations with operators about their experiences with each. With that growing volume of information at hand, the group started seeing the screw press as the best fit for Prattville, and a visit to a plant in Immokalee, Fla. confirmed that for them.

“Immokalee was an eye-opener for us,” said Thompson. “That installation utilizes a Schwing Bioset screw press
(Schwing Bioset, Somerset, Wisc.) for dewatering and creates a Class A product using the Bioset solution. We saw
so many similarities between what Immokalee had dealt with and our own situation at Prattville that we all felt we’d found our answer. ”

 

Pressing Issue

Coming online in August 2019, the biosolids treatment at Pine Creek now begins by taking material from WAS storage basins — where sludge is held, mixed and aerated — and fed to a pair of new Model FSP-1002 screw presses for dewatering. Each of Pine Creek’s screw presses is rated for 1,122 lbs. of dry solids per hour, with a minimum cake dryness of 17% and a 95% minimum system solids capture. With “tweaks” still being made to the process as operations stabilize, the facility is currently getting cake discharged up to 18%. While the performance stats proved key in making their decision, Prattville was also drawn by the self-cleaning function the Schwing Bioset screw press offered, where the units continue to dewater whenever a cleaning cycle is performed. This continuous operation ensures no equalization storage is necessary between dewatering and the Class A operations.

“We have each unit scheduled to clean itself every hour, but that function is flexible and easily changed,” said Napoleon Wilks, Pine Creek’s current plant manager. “We also like the fact that these presses are almost self-operating,” he said. “We have them programmed to run for only seven hours a day, five days a week, which allows us to keep staffing costs down.”

 

A Stabilizing Presence

In addition to being a sound decision for the City, the fact that both Sam Russell and Dale Gandy own and operate
farms helped solidify Prattville’s decision to go with a Class A product. Their understanding of the benefits a soil
amendment product can bring, the ways it can be used and how positive it could be to the community, led to that
decision.

“We like what can be done with a good Class A product — whether it’s a resident needing it for flower beds, for grass in front of City Hall, or a farmer using it on crops. And, after seeing the success Immokalee was having, it made sense to go with the Bioset solution,” said Russell. “We also felt that there was a real up-side in accountability
to sourcing both the dewatering and the Class A process from the same company.”

The Bioset process uses a screw conveyor to take Pine Creek’s untreated biosolids from the screw presses to
a twin-screw mixer where quicklime and sulfamic acid are added and mixed. From the mixer, a Schwing Bioset
KSP-25VKL pumps material through a 22 ft. long reactor. There, the chemical reactions raise the temperature and
the pH level, stabilizing the mixture and creating a product that meets EPA Class A requirements.

According to Wilks, they are maintaining a minimum temperature of 131°F (55°C) in the reactor with a retention time of 40 minutes in accordance with the operating conditions approved by the Unites States Environmental Protection  Agency (USEPA) through the Process to Further Reduce Pathogens (PFRP) in the 503 regulations. “The way we process our biosolids today — pushing a lower quantity through there than our future design conditions — material is actually in the reactor far longer than that,” he said. “The results have been a consistently good Class A biosolid that we take to a field owned by the department, dump it, spread it a bit, and turn it for a few days until it dries to a point that we are able to pass it along to a local farmer — and right now he will take all that we can provide.”

 

Schwing Bioset Municipal Piston Pump  Schwing Bioset Truck Loading

 

No Mistake About It

In the past, a continual stream of trucks, each carrying roughly 6,800 gallons of liquid headed to the field to
land-apply as much as 81,600 gallons of liquid waste per day. Today’s disposal effort involves just two tri-axle
trucks loaded ¾ full per week. And that energy efficiency criteria? It’s been met to a degree they never imagined,
according to Gandy.

“This is amazing to even comprehend but, despite almost doubling the size of the plant in terms of capacity, when we ran the numbers we found that our energy consumption had only increased by 8%,” he said. “Thinking I must have missed something I checked the data several times and even had a representative from Alabama Power verify
it for me. There was no mistake — that’s how energy efficient this plant is.”

The new biosolids effort is working so well that Pine Creek CWF has already begun processing material from
its sister plant, the 4 mgd Autauga Creek CWF. To do that, the City hauls approximately 200,000 gallons of wet
sludge (at 1.75% concentration ) per month from Autauga Creek to Pine Creek for processing.

Said Gandy: “We set out with a pretty challenging to-do list. But tapping the innovative technology available to us,
we feel we accomplished it all — and then some.”

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Tags: Class 'A' Biosolids, Bioset Process, Wastewater Treatment, Municipal Pumps, Screw Press

Schwing Bioset Trailer Mounted FSP 1103 Screw Presses Now Available for Contract Operations

 

Written by Kelly Kramer

 

Schwing Bioset is pleased to announce that we can now help solve your dewatering challenges with our fully automated trailer mounted FSP 1103 screw press dewatering systems. Available for onsite demonstrations and/or contract operations, the 1103 screw press is one of our largest models and is engineered for durability, reliability, ease of operation, and low power consumption, making the units an efficient method to dewater.

As with all of our screw presses, our mobile units are designed for quick set up, ease of use, and high-performance for dewatering all types of wastewater. 

One of the screw press features our customers are most excited about is the self-cleaning wash cycles. With low wash water requirements and automation, dewatering operations do not need to be suspended during cleaning and a cleaning cycle typically lasts less than five minutes.

Once dewatered, the solids can be treated, loaded, hauled away, and/or beneficially reused, depending upon the method of the end user.

For more information on our mobile screw press units, please contact our Regional Manager nearest to your plant. The screw press and Schwing Bioset’s full product offering can be viewed here.

 

Schwing Bioset Mobile Screw Press   Schwing Bioset Mobile Screw Press

 

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Tags: Wastewater Treatment, Screw Press, Dewatering, Mobile Screw Press

Screw Press Proves Efficient in Dewatering MBR Sludge

 

Written by Tom Welch

Version also Published in TPO Magazine, August 2019

 

The Decatur, AR, WWTP had existing dewatering technology that proved to be undersized and inefficient. With the additional demands of a new plant upgrade, Operations staff were struggling to meet current dewatering requirements.

The Design Build team and Owner selected an FSP 802 screw press from Schwing Bioset to replace the existing equipment. The new equipment was installed in the same building with primarily service connection modifications. The screw press started operating in November of 2018.

The improvements in the dewatering operations are remarkable, as it is saving Decatur operational expenses in every category. Dry solids content of the dewatered biosolids have improved from an average of 13% to 17%, resulting in less cake to haul. Solids capture rate has improved from less than 80% to 95%, resulting in a lower return load to the plant. Polymer usage is now at 18 pounds active per dry ton, which is well below the consumption rate of the previous technology reducing polymer expenditures.

In addition to these performance improvements, the dewatering capacity has more than doubled. Where it used to take at least two days to load a 25-ton trailer, the plant can now fill a trailer in 6.5 hours, reducing operator efforts in turn. 

With the widest range of machine sizes for several applications, and mobile pilot units available for testing your materials, Schwing Bioset is your comprehensive solutions provider for dewatering.

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Decatur Dewatering Screw Press

 

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Tags: Biosolids, Screw Press, Dewatering, Membrane Bioreactor

West Rankin Utility Authority to Install Three Schwing Bioset Screw Presses

 

Written by Kelly Kramer, October 2019

 

The West Rankin Utility Authority (WRUA) provides services to several communities in Western Rankin County in Mississippi. WRUA generates approximately 10 to 12 million gallons of wastewater each day, which is currently transmitted to the Savanna Street Wastewater Treatment Plant in Jackson. To take advantage of this service, the authority has to pay Jackson, which costs it a few million dollars each year.

In an effort to save costs in the long run, and operate independently, WRUA has decided to build a brand-new wastewater treatment plant of its own. Schwing Bioset is pleased to announce that our team will be part of this project, with WRUA ordering three of our largest dewatering screw presses, the model FSP1203’s.

The FSP 1203’s are designed to handle a capacity of up to 7,468 dry pounds per hour. For West Rankin, the expectation is to process 24 dry tons per day operating at 60 hours per week, dewatering of 0.75% solids WAS with a 17% solids sludge cake output, and a ≥ 90% solids capture rate.

Schwing Bioset Screw Press     Schwing Bioset Screw Press

The West Rankin screw press system is designed for continuous dewatering of flocculated slurry and consists of a screw press dewatering unit, a flocculation tank, a rotary lobe sludge feed pump, and a liquid polymer blending system. Slow movement and the high-quality design of the structural components guarantee a high service life, and the back-washing cycle cleans the screens automatically so dewatering operations will not be interrupted during washing cycle.

With the new equipment in the new wastewater treatment plant, Schwing Bioset will be able to help West Rankin to bring its system into compliance with federal water quality laws, increase plant capacity, and save on costs in the long run.

To learn more about Schwing Bioset’s dewatering screw presses, contact Chuck at cwanstrom@schwingbioset.com or visit our website.

 

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Tags: Screw Press, Dewatering, Wastewater Treatment Plant

Screw Presses Help Plant Reduce Maintenance Costs

 

Written by Chuck Wanstrom

Version also Published in TPO Magazine, August 2018

 

The city of Bradenton, Florida, operates a wastewater treatment plant that processes roughly 8 million gallon per day. The plant had historically aerobically digested their biosolids and dewatered them to 15% dry solids content using two, 2.0-meter belt filter presses. Due to the age of the belt filter presses, the maintenance expenditures were continually increasing and were creating a burden not only with expenses, but also with personnel time to keep the equipment functioning.

Bradenton began a search to identify new dewatering techniques that could replace the aging belt filter presses.  Several pilot studies were completed, and Schwing Bioset was invited to run our screw press pilot. The pilot proved successful with results of up to 21% dry solids. The Schwing Bioset screw presses were also able to fit within the confines of the available space on the second floor of the existing dewatering building. 

The Schwing Bioset equipment was chosen as the best value and was procured under a sole source contract. The two new FSP902 screw presses were designed into the existing dewatering building and were commissioned early in 2018. The dewatered biosolids exceed the old belt presses cake performance and reduces the city’s hauling and disposal costs while at the same time reducing the amount of wash water required and significantly reducing the maintenance load to city staff. 

Learn more about our screw presses or contact our regional manager closest to you.

 

Bradenton Screw Presses

 

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Tags: Biosolids, Wastewater Treatment, Screw Press, Dewatering, screw presses

City Converts Biosolids Processing Equipment After Fire Disaster

 

Written by Chuck Wanstrom

Version also published in TPO Magazine, February 2019

 

Home to both St. Olaf and Carleton colleges, the City of Northfield, MN, is located approximately an hour south of Minneapolis and has a population of 20,000. The wastewater plant is approximately 3 MGD and has historically produced Class A biosolids via an open alkaline and thermal stabilization process. Disaster struck in May 2018 when a fire destroyed all of the Class A biosolids processing equipment, as well as the surrounding dewatering and odor control equipment in the building. 

Rather than simply replace the old equipment, the city of Northfield evaluated current available technologies and elected to convert from belt presses to screw presses for its dewatering needs and has purchased two machines from Schwing Bioset to accomplish this. Additionally, the city will continue with Class A biosolids production, but they are converting to Schwing Bioset's Bioset process. The Bioset process is a closed process that contains odors and dust that does not require supplemental heat and has also been approved by the USEPA through the PFRP process to operate at temperatures below those specified in the 503 regulations. 

Final detail design of this pre-purchased equipment is underway and the plant is scheduled to be operational later in 2019. To help the plant bridge the gap in biosolids processing while the new facility is in being constructed, the city is also renting a mobile screw press and Bioset trailer to process their current biosolids production. 

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Bioset Process and Screw Press Dewatering

 

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Tags: Class 'A' Biosolids, Bioset Process, Screw Press, Dewatering

Sugar Creek WWTP Screw Press Records Impressive Data

 

Written by Tom Welch, November 2018

The Sugar Creek WWTP, owned by the Sangamon County Water Reclamation District located in Springfield, IL, has two Schwing Bioset model FSP 1102 screw presses and our Class B alkaline stabilization process. The screw presses dewater the plant’s aerobically treated biosolids and the downstream equipment produces the alkaline stabilized Class B biosolids. These biosolids are then windrowed in the District’s storage shed and eventually land applied for beneficial use. Data recorded from a recent site visit on a single screw press in operation was impressive and can be seen below.

Incoming Flow: 280 gpm
Incoming % DS: 1.5%
Throughput: 2,100 lbsdry/hr
Polymer Dose: 12 lbs/ton
Output % DS: 22%
Capture: >95%

 

Check out the included photos and operational videos, which show an overview of the installation and the equipment in action. 

Contact your Schwing Bioset Regional Sales Manager to learn more about how our biosolids management systems may be able to improve your current processes.

 

  IMG_0453_small  IMG_0452_small

 

 

 

 

 

 

 

 IMG_0461_small  IMG_0459_small  

 

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Tags: Alkaline Stabilization, Biosolids, Screw Press, Dewatering

Dewatering with a Screw Press at Bradenton WWTP

 

Written by Chuck Wanstrom, May 2018

The city of Bradenton, Florida, operates a wastewater treatment plant that processes roughly eight million gallons per day. The plant had historically aerobically digested their biosolids and dewatered them to 15% dry solids content using two, 2.0-meter belt filter presses. Due to the age of the belt filter presses, the maintenance expenditures were continually increasing and creating a burden not only in expenses, but also on personnel time to keep the equipment functioning.

Bradenton began a search to identify new dewatering techniques that could replace the aging belt filter presses. Several pilot studies were completed and Schwing Bioset was invited to run their screw press pilot. The pilot proved successful with results of up to 21% dry solids. The Schwing Bioset screw presses were also able to fit within the confines of the available space on the second floor of the existing dewatering building. 

The Schwing Bioset equipment was chosen as the best value and was procured under a sole source contract. The two new FSP902 screw presses were designed into the existing dewatering building and were commissioned early in 2018. The dewatered biosolids exceed the old belt presses cake performance and reduces the city’s hauling and disposal costs while at the same time reducing the amount of wash water required and significantly reducing the maintenance load to city staff. 

To learn more about this project or our screw presses, contact a regional manager or email us.

 

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Tags: Biosolids, Screw Press, Dewatering, Wastewater Treatment Plant