News from Schwing Bioset

New Piston Pumps Help Stabilize Metro Sewerage District Incinerator Operations

 

Written by Tom Welch

Version also published in TPO Magazine, March 2021

 

Piston pumps are used to feed dewatered cake solids to the incinerators at the Metropolitan Sewerage District of Buncombe County, North Carolina, located in Asheville, NC. The original pumps were supplied in 1993 and were sequentially replaced in 2005 and 2007. Due to the growth experienced in the area over nearly 30 years and the continued projected population increase, the pump capacity had to be nearly doubled in the most recent expansion. 

With nearly three decades of exemplary performance for the MSD, Schwing Bioset was again selected to provide the cake pumping equipment package and has recently supplied new KSP 17 piston pumps to feed the dewatered cake solids to the incinerators. The package has performed well for the wastewater plant.

The package included upsized feed hoppers with a delivery piping and actuated ball valve system that can feed either the incinerator or be bypassed to truck loading. To reduce pressure in the pipeline, Schwing Bioset’s proprietary pipeline lubrication design was incorporated to reduce line pressure, extend wear part lives, and minimize the power draw of the hydraulic power pack.

The original pumps had a single discharge line feeding the incinerators. The new pumps were delivered with a unique dual discharge system that splits the flow leaving the pump and enables the incinerator to be fed from multiple locations to stabilize incinerator operations. To accommodate EPA regulations, Schwing Bioset also provided its patented Sludge Flow Measuring System that measures pump output to within +/- 5% of the feed going to the incinerator.

 

Schwing Bioset Piston Pump   Schwing Bioset Power Pack

 

Click here to read more about our Products, then contact us to learn more about this project or find out how we can help your plant too.

 

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

 

Tags: Piston Pumps, Wastewater Treatment Plant

Bissell Point WWTP Expands Biosolids Handling Capability

 

Written by Tom Welch

Version also published in TPO Magazine, October 2020

 

The Bissell Point Wastewater Treatment Plant, owned by Metropolitan St. Louis Sewer District (MSD), is the largest wastewater treatment plant in metropolitan St. Louis, MO. Schwing Bioset had previously provided six (6) KSP 25 piston pumps with 50 HP power packs and a live bottom receiving station at the facility that have been in service since 1993. The piston pumps conveyed 25% dry cake solids to the multiple hearth incinerators, but due to the high amount of additional silt that makes its way through the plant via inflow and infiltration during wet weather events, the dry solids content can soar to over 40%. While this nearly 30-year-old equipment continues to perform admirably, MSD was seeking a solution for the biosolids produced at its satellite plants and wanted to utilize the excess incineration capacity at Bissell Point.

Due to the long and successful history with the current equipment at Bissell Point, MSD purchased a larger KSP 45 piston pump and piping system to transport the received solids into the facility, as well as a push floor truck receiving station with over 50 cubic yards of capacity from Schwing Bioset. The new system is able to handle a high volume of biosolids and complements the existing equipment.

Schwing Bioset Biosolids Piston Pump

Schwing Bioset worked closely with Donohue and Associates to design and provide the new biosolids receiving station for the WWTP. The new receiving station, designed utilizing push floor technology, allows dewatered biosolids to be received from other Metropolitan St. Louis Sewer District facilities so that disposal costs can be minimized by allowing the biosolids to be incinerated. Push floor technology was chosen over the incumbent live bottom as a more efficient and lower maintenance system that also improves material flow characteristics.

The push floor bunker design consists of two hydraulically-driven push frames that reciprocate along the bunker floor. The action of the frames breaks material bridging and feeds solids into the extraction conveyor, and rectangular bunkers allow multiple trucks to back up to and unload into the bunker simultaneously. The bin also includes a retractable bi-fold cover integral to the system when not receiving biosolids, which assists in containing odors and prevents rain, snow, and other tramp materials from falling into the bunker.

Schwing Bioset Receiving Station

As plant staff are already familiar with the equipment and its operation, integration into existing operations has gone smoothly and the new equipment provides MSD flexibility in their management of biosolids from within their service area into the future.

Click here to read more about our Products, then contact us to learn more about this project or find out how we can help your plant too.

 

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

 

Tags: Wastewater Treatment Plant, Biosolids Piston Pump, Receiving Station

Biosolids Plant Up and Running at Paragould WWTP

 

Published in Paragould Daily Press, August 2020

 

Thanks to a newly completed $5.15 million biosolids plant, not all the waste at Paragould Light, Water and Cable’s Wastewater Treatment Plant is actually going to waste. 

“We send out two 12-[cubic] yard trucks of biosolids a day, Monday through Thursday,” said plant Operations Manager David Romine on Monday. 

Romine said the biosolids, a byproduct of wastewater treatment and processed by the plant’s new Schwing Bioset equipment, go out to area farmers at a cost to them of $5 a cubic yard delivered, such that a fully loaded truck would cost $60.

In addition, the new equipment enables a savings of about $100,000 a year on the cost to operate and maintain the equipment, compared to the old system.

The Schwing Bioset system enables sludge produced to receive a rating of Class A EQ biosolid under the EPA 40 CFR 503 regulation. “The EQ means it’s ‘exceptional quality,’” Romine said, “which means you don’t have to do anything special in order to use it anywhere [as fertilizer].”

 

Click here to read the full article in the Pargould Daily Press

 

The Bioset Process allows the product to be used as a fertilizer under regulation for Class A EQ. Pictured is the Bioset unit, dewatering screw presses, piston pump, and truck loading operation. 

20200831_110158 (2)  20191003_134927

 

 

Tags: Class AA/EQ Biosolids, Dewatering, Wastewater Treatment Plant

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.” 

 

Click here to read more about our Products, then contact us to learn more about this project or find out how we can help your plant too.

 

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

 

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

Capital Idea for Biosolids Processing at Springfield Wastewater Treatment Plant

 

Written by Larry Trojak, Trojak Communications

Version also published in WE&T Magazine, December 2019

 

Springfield, Ill., wastewater treatment plant supplements its sludge disposal effort with a pair of screw presses and alkaline stabilization.

Effective wastewater treatment is predicated on equal parts science and planning. The science element of that premise includes keeping abreast of the latest technology to best manage both the treatment and disposal of biosolids. For the Sangamon County (Illinois) Water Reclamation District, that has meant rethinking its approach to biosolids, particularly in the area of dewatering prior to land application. Once solely dependent upon liquid applying its Class B byproduct, the District’s Sugar Creek Wastewater Treatment Facility recently upgraded its process to include a pair of fully-automated screw presses and a Class B alkaline stabilization system from Schwing Bioset, Inc. (Somerset, Wis.). Today, with a viable option to that liquid process in place, the plant is generating more than 17,000 lbs. of Class B cake monthly, and has peace of mind that its biosolids effort is poised for future growth.

 

Schwing Bioset Screw Presses   Schwing Bioset Screw Presses

 

A Pair of Plants

In addition to being the state capital, the city of Springfield (and immediate surrounding areas) hosts scores of facilities related to a booming agribusiness industry. These include one of the nation's largest stockyards and feeder cattle facilities, as well as various creameries, meatpacking plants, flour mills, etc. To meet the demands these and other industries place on the area’s wastewater system, a pair of treatment plants were built: Spring Creek in 1928 and, to accommodate area growth, a sister plant, Sugar Creek, in 1972.

“Since that time, both plants have been retrofitted to better handle increased volumes,” said Steve Sanderfield, Sugar Creek’s plant supervisor. “Spring Creek is by far the larger of the two with an average flow of 32 mgd and a peak of 80 mgd. Here, we average 15 mgd and top out at 37.5 mgd, so our max is really only 5 million gallons more than their average. Spring Creek has been updated every couple of decades, but this plant had remained fairly constant until a 2017 upgrade which resulted in a 50% increase in both the average and peak flows. That upgrade also paved the way for the current change to the dewatering effort.”

The most recent changes were improvements for flow control and diversion to wet weather treatment facilities that included mechanically cleaned perforated plate fine screens, grit removal tanks, and activated sludge tanks designed to meet both current and future effluent phosphorus limits.

 

A Better Alternative

In addition to the changes mentioned above, the biosolids area also underwent a significant upgrade, including those areas for thickening, stabilization, dewatering, and storage. Until those changes were made, Sanderfield said they had only one option for disposing of the sludge created in their treatment process.

“Since the mid 1990s, to meet 40CFR Part 503 requirements for Class B Biosolids, we post-stabilized liquid sludge (1.5% TS) by adding standard hydrated lime in a slurry,” he said. “Batches of the biosolids/lime mix were held in batch mixing tanks for 24 hours, after which (if they met 503 pH requirements) they were land-applied on a 30-acre farm owned by the District. If the batch pH dropped overnight below the acceptable standard, it would have to be “re-limed” and given another 24 hours to achieve the requirements within the standards. The stabilized liquid sludge was then pumped and spray-applied through a series of fixed irrigation nozzles installed throughout the farm. Because it is a liquid-sprayed application, large sludge storage tanks are required for times when field limitations (wet seasons, frozen ground, etc.) prevent application.”

While it was less expensive to apply the stabilized sludge in liquid form, those shortcomings prompted a re-thinking. Taking a page from their sister plant’s playbook, they began looking into options for dewatering prior to land application.

“Spring Creek was already dewatering with screw presses and sending the dewatered product to a pad for drying and eventual land application,” said Sanderfield.” However, because our process differs from theirs — aerobic versus anaerobic — and we saw some shortcomings in the presses they use, we decided to look at what else was out there. Vendors were invited to show us their products and, after an impressive two-week pilot test and subsequent bid process, we chose a pair of FSP 1102 screw presses from Schwing Bioset.”

 

Schwing Bioset Municipal Pump   Schwing Bioset Storage Silo

 

Two Are Better Than One

The model of presses in place at Sugar Creek represent one of the largest designs Schwing Bioset offers. Low speed by design, they offer dewatering results comparable to high speed centrifuges and — by nature of that slow speed and robust construction — provide a much longer lifetime of service. Sanderfield was particularly interested in one feature of the screw press: a split-screen cage that both simplifies screw removal and minimizes footprint requirements. The split cage allows the sealing lip and screen to be replaced with the screw in place — much simpler than removing the screw from one end of the machine.

“Once we knew the press would give us the product we needed, we tended to focus on the upkeep side of things,”
he said. “For example: how easy would the units be to repair if one of them went down? How self-cleaning is it? What kind of wear items does it contain? That last point was important to us. The presses at Spring Creek utilize brushes that wear down and, once they do, we have to pull the entire screw out to change them. That’s a huge undertaking we wanted to avoid over here.”

Immediately after the pilot test, Sanderfield was impressed with the self-cleaning process for the Schwing Bioset
presses. Unlike the units at Spring Creek which simply spray as the disc rotates and must be done when the unit is
not de-watering, these utilize a low-volume, high-pressure spray ring that tracks down the length of the screw — during operation.

“This approach is so much better than others we’ve seen,” he said. “Our dewatering operation does not need to be
interrupted for cleaning, and the cleaning cycle is typically only three to five minutes long, once per day. We’ve also
found that after a thorough cleaning the presses can sit for a while and, when they are needed, will be in operation
immediately — nothing hardens up in the lines. Because we don’t run the presses continuously here at Sugar Creek, that was important to us.”

 

Strength in Numbers

Although Sugar Creek never intended to run both presses at once, they nevertheless opted to go with two units rather than just one, based on equal parts the desire for redundancy and an eye toward future growth.

“For us, the purchase of the second press was definitely driven by the need for a backup,” said Sanderfield. “We
are in a situation here where a press failure or, more likely, one of the pumps we have feeding each press, would be
catastrophic to the process. That’s no longer a concern for us. In addition, as this area continues to grow, we are better poised to meet that growth without the need for any major overhaul.”

At Sugar Creek, sludge enters the press at roughly 1.3% solids, mixes with a polymer, and exits at 25 to 30%
dry solids. While they are extremely pleased with those numbers, Sanderfield is quick to point out that, as with any
press system, they have to take additional steps to deal with the filtrate. “The filtrate tends to be high in ammonia
and phosphorus, so it’s considered a side stream,” he said. “When we bring that back to the plant we have to be certain to do so slowly. So when the presses run, the filtrate that is getting squeezed out is pumped back at a slow rate and is controlled by the tank level. So, if we program it to start pumping when it’s at five feet and stop when it is at three feet, that’s what it will do.”

 

Push of a Button

Sanderfield’s allusion to equipment autonomy is telling. Automation of the presses was also a huge consideration
for Sugar Creek when making their purchase decision, and Sanderfield said they are very pleased with the level
of self-operation the 1102’s can maintain. 

“We start and stop it, monitor it, and run tests on the solids as it comes out,” he said. “But, for the most part, we are
able to hit ‘start’ and the sludge pump will control the feed rate that we set, the presses will do their thing, the
polymer will activate — it essentially runs itself and fits perfectly with the rest of the process which is also heavily
self-operating.”

From the screw press the biosolids still needed to be treated per the EPA 503 to Class B levels. The project
had already started down the path to utilize another technology, but after piloting the Schwing Bioset alkaline
stabilization technology with the screw press, the project switched gears. The biosolids are now routed from the
screw presses to the Class B lime system (also supplied by Schwing Bioset) where quicklime is introduced to
stabilize the dewatered biosolids by elevating the pH. 

“As with the liquid application, according to EPA 503 we cannot field apply the material until we’ve met the 24-hour
pH criteria,” said Sanderfield. “Doing so eliminates the risk of rodents, birds, animals, etc., coming in contact with
the sludge and possibly transferring diseases to other animals or people. Once we’ve stabilized it in the lime
system that’s no longer an issue.”

And, with an eye toward the future, Sugar Creek’s Class B lime system is also designed to facilitate expansion into a Class A Bioset alkaline stabilization process, should they choose. After treatment in the lime system, sludge — now with the consistency of a slightly wet modeling clay — is conveyed to a drying pad where it gets regularly turned using a skid-steer loader with a Brown Bear windrow turning attachment; once fully dried, it is ready for land
application.

 

Just Gets Better

If things seem to be going great for the team at Sugar Creek, it’s because they are. They just wrapped up a
well-attended open house for area residents and local officials, they are meeting all the necessary biological and
phosphorus thresholds without the use of chemicals, and they were just recently nominated for Plant of the Year in
Illinois.

“That last fact — a nomination for Plant of the Year — is mind-blowing, given that we’ve only been online for over a
year,” said Sanderfield. “Things were crazy here for quite a while, but we are now settling in to a nice routine and the Schwing Bioset presses and alkaline system have helped provide a lot of that peace of mind. We will still do both solid and liquid land applications of the sludge — that’s always been the plan. But, since we can press in five days what would probably take us three weeks to do otherwise, the process is far more efficient than it’s ever been.”

 

Click here to read more about our Products, then contact us to learn more about this project or find out how we can help your plant too.

 

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

 

Tags: Alkaline Stabilization, Wastewater Treatment Plant, screw presses

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.

 

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

Tags: Screw Press, Dewatering, Wastewater Treatment Plant

Storage Silos for West Palm Beach Improvement Project

 

Written by Tom Welch

 

The East Central Regional Water Reclamation Facility has a rated treatment capacity of 70 million gallons per day and serves the cities of West Palm Beach, Riviera Beach, and Lake Worth; Palm Beach County, and the Town of Palm Beach.

Prior to the anaerobic digestion improvements, the plant utilized sludge decanting to concentrate solids to 2%, aerobic digestion to partially destroy solids, and belt press dewatering to remove excess water from biosolids, with dewatered cake hauled to the Solid Waste Authority – Palm Beach County (SWAPBC) Pelletizer Facility.

To help improve the plant’s processes, the anaerobic digestion project included mechanical sludge thickening to concentrate solids to 5%, temperature-phased Anaerobic Digestion to destroy more solids, and centrifuge dewatering to remove more excess water. 

Key to the whole process are new state-of-the art sliding frame sludge storage silos from Schwing Bioset that offer the plant flexibility in its operations by providing buffer capacity between the centrifuges and trailers. Sliding frame technology has largely displaced older live bottom truck loading technology at the wastewater plants as it holds many advantages, including; vertical sidewalls, no exterior ribbing required for structural integrity, very few and simple components for O&M activities, and flexible unloading configurations to accommodate variable trailer sizes. Once the dewatered Biosolids are loaded in trailers they continue to be transported to the SAWAPBC. 

Schwing Bioset Sliding Frame Silos           Schwing Bioset Biosolids Truck Loading

 

Schwing Bioset provided a quantity of four, 55 cubic yard silos with a truck loading conveyor for efficient truck loading. Overall the project reduces hauled biosolids by 15,000+ wet tons per year and reduces truck hauling costs and trips from the plant to SWAPBC.

To learn more about Schwing Bioset’s sliding frame silos, visit our website here or contact your Region’s Representative.

 

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

Tags: Sliding Frame Silos, Truck Loading, Wastewater Treatment Plant

Water Reclamation Facility Steps Up its Approach to Biosolids

 

Written by Larry Trojak, June 2018

 

Central Florida is One “Class A” Place

Much like the State of Florida itself, the Water Conserv II facility, located in Orlando, is all about change. Almost since its inception in 1961, Water Reclamation Facility  (WRF) has been undergoing periodic upgrades, process changes and, at times, major overhauls to keep pace. So it should come as no surprise that, when confronted with the need to replace major anaerobic digestion components that were impacting capacity, all options were on the table. And when the Florida Department of Environmental Protection (FDEP) indicated that newer, tougher regulations would be impacting continued production of their Class B biosolids product, a range of alternatives was examined. The end result of those efforts is a new Class A Exceptional Quality (EQ) product created through use of the Bioset Process from Schwing Bioset, Inc. (SBI, Somerset, Wisc.) which effectively creates 120,000 lbs. of field-ready fertilizer product per day.  

Silo_Small

 

Use Then Reuse

Originally constructed in 1961 as the 4 mgd McLeod Road Treatment Plant, the Orlando facility was upgraded to 12 mgd in 1972 to deal with the area’s rapidly growing population and then further expanded to 25 mgd. Then, in the early 1980s, a number of factors, including the realization that the plant’s discharge was adversely affecting the health of nearby waterways, prompted the City of Orlando and Orange County to team up and create what is today called the Water Conserv II Distribution Center (DC) in west Orange County, about 20 miles from the Water Conserv II WRF. The DC reuses about 35 mgd of treated wastewater (reclaimed water) in west Orange County for agricultural, residential and commercial uses, as well as rapid infiltration basins (RIBs) to help with aquifer recharge. According to Paul Deuel, assistant division manager for the City of Orlando Water Reclamation Division, the scope of what was planned for the newly revised treatment plant was impressive.

“Much of this was driven by the growth we were seeing in the early 1980s and the projected impact on the aquifer that serves this area,” he said. “In addition, the EPA was mandating that discharge issues at nearby Shingle Creek be resolved. So, the Water Conserv II DC, which combined newly improved processes with the use of reclaimed water for area irrigation, was born. That last point is huge: up until then, very little agriculture involved the use of reclaimed water. The Water Conserv II DC went that route and for a long time was the largest citrus irrigation project in the world to do so.”

The move to make the resource available resulted in a contract which provided early participants access to free reclaimed water for a period of 20 years. For some, according to Deuel, the benefits proved invaluable.

“In the case of the citrus growers, this agreement provided a guaranteed water source, even in times of shortages or drought,” he said. “In addition, it could be used for frost and freeze protection when the lives of the trees themselves were at risk. Once we became established, additional users joined in over the years, including several area golf courses, Valencia Community College, Universal Studios’ theme park (which uses it both for site irrigation and in their cooling towers), the Mall at Millennia, even apartment complexes and single-family homes. It has really proven itself an invaluable resource.”

 

Time Takes a Toll

As mentioned, Conserv II WRF has been undergoing change of one sort or another since its inception. When major components in the anaerobic digestion area began to show signs of wear — and failing on an increasingly regular basis — the facility team started running the numbers to weigh the cost of shoring up the Class B biosolids operation or going in a new direction entirely.

“We started looking at the costs needed to rehab the anaerobic digesters to achieve [Class B] biosolids,” said Steve Shelnutt, Water Conserv II WRF plant manager. “At about the same time, FDEP advised us that new regulations, specific to the generation of a Class B product, were being implemented. It was obvious that continuing to do Class B was going to be more challenging and more costly. So, we began looking at alternatives available to us.”

Shelnutt said they contracted with engineering firm Black & Veatch and considered a combined heat and power process that still relied on anaerobic digestion but, because it went into the thermophilic range, it would give them the Class A EQ product they desired  “However, it also added a nutrient load back to the plant,” he said. “So, they sought to remedy that by recycling the gas it created, treating the side streams, and so on. Unfortunately, the project costs started growing into the $40-60 million capital range — far beyond what we had envisioned.”

 

Let the Games Begin

As is so often the case in any industry, word that Water Conserv II WRF was seeking alternative processing methods traveled quickly. One of the first to call upon them, according to City project manager Kristi Fries P.E., was Brian Schuette, vice president of Moss Kelly, Inc., SBI’s Florida sales representative.

“Brian came in and, based on equal parts: what the Bioset Process could do for us and its estimated costs, quickly got our attention,” said Fries. “He told us that he could take us into a Class A EQ fertilizer-grade product for about $1.8 million. Compared with the other proposal which seemed to be growing more expensive by the day, this seemed almost too good to be true. At the same time, we were hearing from other manufacturers who pitched their processes, each of which had some good points, but ultimately didn’t give us what we really needed.”

The alternatives examined included upgrading the anaerobic digesters, a process that employed a high-pressure steam pre-treatment, another which used a technique to accelerate the composting process, and others.

“We did an evaluation of capital costs for each, measured it against the proposed end-product, and decided that we would move forward with the Bioset Process,” said Shelnutt. We also took a ‘field trip’ to two different Florida locations where the process was already in operation and liked what we saw. In fact, our chief operator and I spent a good deal of time talking to the staff discussing the process and hearing how they felt about it. That really helped us make our decision.”

Bioset_Edited_Small

 

Feeling the Heat

The Bioset Process which Water Conserv II WRF has embraced takes biosolids that have been dewatered to about 15% dry solids and, using Schwing KSP-25 piston pump, routes it to a twin-screw mixer in which quicklime and sulfamic acid are added and blended. This type of mixing ensures a homogeneous product and alleviates issues such as unreacted lime in the final product — and the associated costs associated with it.

“At that point, the Schwing KSP-25 piston pump feeds material into the reactor in which heat from the acid and quicklime raises the pH level, thereby stabilizing the biosolids mixture and creating a product that meets EPA 503.33 requirements,” said Shelnutt.

Because the ammonia that is generated through addition of the lime is entrained with the biosolids inside the reactor, thereby killing the pathogens, the Bioset approach has been approved as a process to further reduce pathogens (PFRP). This approval allows the Bioset process to operate at 55°C (131°F) with a residence time of 40 minutes (versus 70°C (158°F) for 30 minutes) lowering operating costs by approximately 35%.

The stabilized Class A EQ product exits the reactor and is pumped directly to a pair of waiting trailers. Even though it is discharged from the process above 25% dry solids, the new product has very little surface tension until it cools, improving its flow characteristics and making it self-leveling in the trucks. According to Deuel, having SBI involved took care of an important step in the upgraded biosolids process: finding a customer for the end-product.

“We are fortunate in that Schwing Bioset has arrangements worked out with customers here in Florida who are anxious to take the Class A EQ material,” he said. “In this case, it is an organization called the Deseret Ranch which runs a cattle operation on about 295,000 acres (450 square miles) in Central Florida. And while they are happy to take the product in its raw form, Bioset will also accommodate customers who demand a pellet or finer product. Not having to deal with [the disposition of] the biosolids has been a nice bonus for us.”

 

Weathering the Storm

Schwing Bioset’s sister company, Biosolids Distribution Services (BDS) provided the first six months of hauling and marketing of the Class A EQ material .  Utilizing more than 15 years’ experience, BDS was able to add the production from the Water Conserv II WRF to their current operation. 

The benefit of having BDS haul Water Conserv II WRF’s Class A EQ product was felt soon after the equipment was installed, as Hurricane Irma struck in September of 2017. Due to the high-water table levels after the hurricane’s passage, virtually all sites available for Class B land application couldn’t be utilized and it wasn’t until three months later, when groundwater levels dropped, that those fields could be accessed again. The plant would likely have incurred substantial additional disposal costs taking Class B material to either landfills or longer-distance application sites that could still receive Class B biosolids. BDS and the city only missed one day of scheduled hauling — the actual day the hurricane struck. Otherwise it was business as usual leading up to and immediately after the storm.

 

The Need for Feed

Making the switch from a Class B biosolids product to a Class A EQ was not without its challenges. For example, at 371 cu. ft., the reactor installed at the Orlando site is quite large, yet the footprint in which the major components had to be installed was extremely tight. In addition, one of Water Conserv II WRF’s primary stipulations said that that their new process needed to be fully automatic.

David Bass P.E., Water Reclamation Division manager added. “We needed to automate everything. So the programming needed to achieve that was intricate and demanding. But Schwing Bioset, working with our own programmers, was able to make it happen.”

A good example of that automation at work can be found in the system’s lime feed process. At Water Conserv II WRF, should the temperature in the reactor drop, the lime feed will automatically increase; conversely, if the process is found to be running too hot, the lime feed will decrease. The program also monitors the output of the transfer pump and — whether they are running one or two dewatering presses — if the pump starts adding more sludge to the outside hopper it will also speed up the lime.

“This has taken our biosolids process to a whole new level,” says Shelnutt. ”We’ve gone from a situation in which the staff felt they needed to monitor things constantly, to one in which they are totally comfortable letting it operate as designed. Everything is now controlled by the HMI (human machine interface) on the control panel and, despite a few hiccups at the outset, it has proven an outstanding solution for us.”

 

All About the Change

In its previous Class B biosolids scenario, four belt filter presses discharged the dewatered biosolids onto two belts that led to an incline conveyor, then to a traveling conveyor which deposited it into trucks below. True to Water Conserv II WRF’s spirit of continual improvement, those two belts are in the process of being converted to screw conveyors and rather than converging in the center, will go in opposite directions and dump into a pair of Schwing KSP-25 transfer pumps.

“Those pumps take the biosolids to the Bioset unit outside,” said Shelnutt. “While it would have been great to have the entire biosolids process under one roof, size constraints made that impossible. This plant is on an area that measures less than 40-acres — relatively small for a plant of this size — and any open space we have remaining has already been slated for other use such as new clarifiers, additional aeration, etc.  However, this does allow us to keep the Bioset process close to the trailer loading area, which was also important for us.”

Shelnutt added that the system design features a pair of Schwing Bioset bulk storage silos for redundancy in the lime storage area. They will also be keeping the traveling and incline conveyors as a backup, should there be anything that results in a service interruption to the Bioset system. In that case, they can simply send material through the belt presses and haul it to another facility for processing. “It’s an option, albeit an expensive one, but it is better than being completely out of business,” he added.

The biosolids process now in place at Water Conserv II WRF is capable of processing 20 dry tons/day and Deuel said that under normal conditions they would do about half that. “Right now, however, we are pulling material that has been stored from the shutdown of the anaerobic digesters,” he said. So we are doing between three and six trailers a day, depending on hauling and plant variables.”

 

Solid Relationship

According to Shelnutt, the relationship between the Water Conserv II WRF team and Schwing Bioset has been a good one, based equally on the product’s proven performance and the company’s quick, consistent response to their needs.

“It seems like such basic business sense, but while far too many companies don’t seem to get it, Schwing Bioset does,” he said. “By way of an example: we had a problem with an acid hopper, determined that we caused the problem, and went back to the manufacturer to order a new one. They wanted more details and were dragging their feet on the replacement. SBI found out about it and interacted with that manufacturer directly to make things right. We felt that was over and above what is expected of an equipment supplier — but it’s solidified our relationship.”

Obviously, given the savings cited and the market for the product, Water Conserv II WRF’s decision to go with the Bioset process was largely based on economic concerns. However, according to David Bass, they were also committed to the idea of having a usable, in-demand product leaving their facility.

“It seems like so many biosolids management facilities are coming and going; people are losing their permits, others are opting to leave the industry, and so on,” he said. “And to a certain extent, I can see that. If we were still generating a Class B product, the increasingly stricter regulations that the FDEP and EPA are now promulgating require a much larger application setback than previous regulations. We wanted to eliminate issues like that, create a viable product, and feel good about our operation. The Bioset Process was definitely the right solution for us at this facility.”

 

To learn more about this project or how we can help your plant, contact a regional manager or email us.

  

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

Tags: Bioset Process, Class AA/EQ Biosolids, Pumps, Biosolids Storage, Wastewater Treatment Plant

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.

 

1  DSCN8025

 

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

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

Metro WWTP Upgrades Piston Pump Sludge Flow Measurement System

 

Written by Chuck Wanstrom, March 2018

 

The Metro WWTP, operated by the Metropolitan Council of Environmental Services (MCES), located in St. Paul, MN, has an average daily flow of 215 million gallons per day (MGD) of incoming flow. Prior to 2004 the plant had been utilizing multi-hearth incinerators to burn their biosolids. A new incineration facility utilizing fluid bed technology was commissioned in 2004 and included a dewatered biosolids storage and feed system supplied by Schwing Bioset, Inc (SBI).

The feed system included four sliding frame silos providing intermediate storage of dewatered cake to provide a buffer in centrifuge and incinerator operations. Each of the four sliding frame silos were equipped with two KSP 45V(HD)L piston pumps to transport the dewatered cake to the incinerators. Each piston pump is equipped with a dual discharge to split the biosolids flow to multiple incinerator injection points, as well as a Sludge Flow Measuring System (SFMS) to measure within 5% the amount of biosolids being pumped into the incinerator. The SFMS is a critical piece of the operation as this is required to satisfy US EPA reporting requirements. This proven equipment configuration and flow measuring system has been utilized at numerous other facilities across North America for over 20 years.

Schwing Bioset has recently developed an improvement in its SFMS to reduce the possible sources of error that can be introduced with variations in pumping speed during operation. This next generation of SFMS results in an even more accurate means of recording and reporting biosolids flow and is further evidence of Schwing Bioset’s commitment to developing and improving its technology to better serve its family of customers. After nearly 15 years of reliable service, the Metro plant, and its continuing commitment to excellence, is currently in the process of performing upgrades throughout its Solids Management Building and is converting its piston pumps to this next generation of flow measurement. Schwing Bioset looks forward to many more years of supporting MCES and to the continued success of this impressive facility.

If you are currently using an SBI pump equipped with our SFMS and would like more information on upgrading your equipment to the latest generation of flow measurement, please contact us at (715) 247-3433 or schwingbioset.com/contact-us.

 

WWTP Schwing Bioset Piston Pump

 

 Download Our Brochures    or Application Reports

Read More Schwing Bioset  News and Blog Articles

 

Tags: Piston Pumps, Biosolids, Wastewater Treatment Plant