News from Schwing Bioset

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

Replacing Failing Filter Press Yields Huge Improvements

 

Schwing Bioset Application Report 22, Seneca Water

Written by Larry Trojak, Trojak Communications

Version also published in WE&T Magazine, October 2016 Issue

 

When the Seneca (S.C.) Water Treatment Plant embarked on a recent expansion project, its overall goals were fairly straightforward: eliminate the use of chlorine in purification, relocate its new chemical treatment process, and upgrade the alum sludge dewatering operation. On that last point, plant officials opted to replace an outdated and difficult to maintain batch filter press with a different technology altogether — a fully-automated screw press — to handle its dewatering needs. In doing so, they not only eliminated an ongoing maintenance headache, they also dramatically improved the efficiency of their dewatering operations as well as their overall residuals management operation.

 

Water for Sale

Built on a hill overlooking Lake Keowee, the Seneca Water Treatment Plant is a 20 million gallon per day (MGD) facility located in Seneca, South Carolina, that serves more than 39,000 residents in and around Oconee County in the far northwestern part of the state. According to Steve Fletcher, the lake is owned by Duke Power Company, which allows the City to draw raw water for municipal purposes.

“As part of the agreement with Duke Power, we take in and treat the lake water, then, once purified, wholesale it to area communities,” he said. “That 20 MGD number is our peak permitted flow — our actual volumes vary, but are generally in the seven to 10 MGD range.”

Storage facilities for the treated and purified water currently consist of three ground storage clear wells and eight elevated tanks with a total capacity of 6.5 million gallons.

Seneca Water Screw Press

 

Risk Management

Until this latest expansion, water disinfection was done using chlorination which, while effective, was seen as a serious potential hazard, said Fletcher.

“When this plant was first built in 1968, there was literally one house in the immediate area,” he said. “However, the lake’s popularity has attracted large-scale development — both residential and commercial — and today the area immediately around the water plant is dense with some very nice homes. Should one of our three one-ton cylinders of chlorine gas have ruptured, it could have seriously affected people for a mile around the plant. We didn’t want to risk that any longer and decided that generating our own sodium hypochlorite was a much safer alternative.”

In addition to the change in chemical process, the expansion also resulted in a brand new operations building which houses not only the offices and administrative staff for the plant, but also includes a new laboratory facility and a common area that will be made available to city residents for meetings and other functions.

“This project really grew as we went along, as did the price tag which went from $3 million to $10 million.” Said Fletcher. “But we knew that, as long as we were making changes, we might as well make all the improvements we’ve talked about wanting for a long time.  Right now this is one of the most functional — and beautiful — water treatment plants around.”

 

Residuals Shortcomings             

Treatment of alum sludge at Seneca Water, the by-product of using aluminum sulfate as a coagulant, has a storied history. When the plant was originally built in 1968 there was no treatment effort at all; sludge was simply returned to the lake. The advent of clean water regulations changed all that and Seneca Water was soon recovering and disposing of its sludge in an area landfill. To dewater the material, Fletcher said the plant officials in about 1990 opted for use of a plate and frame filter press.

“Once installed, that press remained in place up to the recent upgrade and eventually became one of the main motivations behind a re-tooling of the sludge process,” he said. “I’m sure that, in its day, it was a solid performer. In recent years, however, it had become such a headache to maintain that it was a full-time job just keeping it operational. In addition, it ran as a batch process which meant it had to stop after every batch of dewatered sludge it created. We knew there were better solutions available out there and we started looking at them.”

It’s worth noting that the overall configuration of the alum sludge plant was sorely lacking as well. At the time, sludge was collected in the backwash holding basin, sent to a vertical turbine transfer pump, then routed up to a thickener.

“Unfortunately, that thickener was on the top of a hill on the other side of the plant,” said Fletcher. “Hardly the most efficient layout. Once thickened, sludge came back down the hill into a diaphragm pump and into the filter press. The transfer pumps were not only costly to run and almost always in need of rebuilding, they weren’t really designed to pump sludge so they were continually stopping up. All those things collectively got us thinking about ways to improve the overall biosolids process — starting with the press.”

 

Trials and Errors

After a fairly lengthy process of demos and trials, Seneca Water, working through their consulting engineer, chose a screw press from Schwing Bioset, Inc. Fletcher said the unit best met established criteria which were focused on cost versus performance.

“We looked at a number of manufacturers and a number of different technologies and knew that the Schwing Bioset unit would best meet our needs,” he said. “Our old press was taking in sludge with 4% to 5% solids and dewatering it to about 24% solids, so we were hoping for at least that. However, many of the presses we tested were giving us product in the 16% to 17% range — we definitely didn’t need a step backward. The team from Schwing Bioset brought their demo unit online and almost immediately we were getting dewatered sludge in the 28% to 32% range. Equally important, however, was the fact that the screw press was fully-automated rather than a batch-process design. That meant we no longer needed to have a man assigned to the press six hours a day, every day, as we’d done in the past.”

With Seneca Water committed to the Schwing Bioset screw press, additional changes were made to the alum sludge processing line, including the addition of a Model 300 large bubble mixer from Pulsed Hydraulics, Inc. (Oroville, Wash.).

“In the past, we’d had problems with the sludge settling and stagnating in some of the lower parts of the holding basin,” said Tommy Clayton, a Class A operator at the Seneca plant. “This PHi bubble mixer keeps the sludge moving and further increases production through the Schwing Bioset screw press. It has very low energy demands, has no other moving parts and runs off a compressor which we need for the press as well. The two are a perfect fit.”

Seneca Dewawtering Screw Press

 

Pressing Issues

The increase in production with the screw press in place was immediate and substantial. Because of the batch nature of the former plate and frame press, Seneca Water was forced to process sludge continuously all year long. According to Fletcher, that has changed with the addition of the Schwing Bioset unit.

“Now, with the continuous dewatering process we can have material being collected in the basins and, when ready, can get caught up in just two to three weeks. There really is no comparison between the two presses, but it’s safe to say that we can probably do close to two tons of alum sludge a day with the Bioset press while the old press took two days to do just a ton.”

Those old production figures were affected by both the cleaning process and by maintenance-related downtime. The plate and frame press, said Fletcher, had to be washed down after every batch — a process that could take as long as three hours. By comparison, the Bioset screw press has a self-cleaning function in which the screen gets sprayed — while the unit is in operation — cleaning it off.

“That means continuous production and no lost time, which is huge” said Fletcher. “We are saving no less than six hours a day in manpower alone just by nature of not having to have a man on the filter press handling the batch process, cleaning it and so on. However, without a doubt, we are benefiting most by finally having a press that is reliable — we are no longer having to constantly work to keep that unit operational. We simply start up the Schwing Bioset unit and it runs all day long.”

 

Working Together 

Once dewatered, Seneca’s sludge is collected and sent to an area wastewater treatment plant where it is mixed with that facility’s dewatered biosolids and trucked to a landfill in a collaborative city/county effort.

“There are so many facets of our operation that have been improved with this latest expansion,” said Fletcher. “We are much more efficient now, our process is better and far more reliable, and the risk of danger from chemical exposure has been eliminated. That’s a very nice turnaround for us and a benefit to the Seneca community as a whole. We couldn’t be happier with the way things turned out.”

 

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Tags: Water Treatment, Screw Press, Dewatering, Water Plants

Pressing Issues (for Water Treatment Plant)

 

Published in WaterWorld Magazine, February 2016. Written by Larry Trojak.

When a new plant that Davidson Water Inc. (Lexington, N.C.) had recently inaugurated started producing levels of solids almost double what it had anticipated, the company worried that all its advance planning was for naught and the dewatering facet of the process was doomed. However, one of the key components in that effort, a new screw press, met the challenge, giving plant operators the results - and the peace of mind - they needed.

To view this story in its entirety on WaterWorld Magazine's website, click here.

 

To learn more about Schwing Bioset and our screw presses, click here. 

 

Tags: Water Treatment, Screw Press, Dewatering, Ferric Sludge

We Dewater Water Plants Too - Part Two Alum Sludge

 

Written by Tom Welch, October 26, 2015

Seneca Light & Water, serving the region of Oconee County in South Carolina, operates a 20 million gallons per day (MGD) Water Treatment facility that uses the 18,500-acre Lake Keowee as its source.  The original plant started in March of 1969 as a 4 MGD facility and has advanced to the current rating with several upgrades.

The Seneca water plant uses aluminum sulfate as a coagulant to lower the turbidity of the water.  After a series of processes, the waste aluminum sulfate is dewatered so that as little water as possible is hauled away with the solids.  Historically, a plate and frame press had been used.  Although that equipment provided a reasonably dry product, about 24% solids, the equipment was only able to run in batch processes, was labor intensive, and was not a clean process to work with.

In 2012, Seneca began a search to identify new dewatering techniques that could replace the aging plate and frame presses.  Several pilot studies were completed, and Schwing Bioset was invited to run their screw press pilot in May of 2013.  The pilot proved successful with a result of 27% solids, which was better than the performance of the existing plate and frame press, as well as the other screw press that had been tested.  The Schwing Bioset equipment was chosen as the best value and the new FSP 0403 screw press was designed into the new dewatering building that was commissioned in September of 2015.

The dewatered alum sludge is hauled to the nearby wastewater treatment plant and mixed with the dewatered Biosolids and then hauled jointly to the landfill.  Now in normal production, the FSP 0403 screw press is producing 30% solids on average with a high of 34%, which is even better than the pilot results.  This is all being done with a polymer dose of 5 pounds of active polymer per ton, which has proven to be very cost effective thus far.

Seneca Light & Water has met their goal of replacing their aged plate and frame technology with a very energy efficient screw press that allows continuous processing. 

The new facility in Seneca, South Carolina, is Schwing Bioset’s second successful water plant startup in the Carolinas this year.

To read Part 1 of this blog, which discusses the screw press installation at a water plant using ferric, go here.

To learn more about our dewatering capabilities or this project specifically, contact this blog’s author, Tom Welch, and/or visit our website here: SBI Screw Presses. For other inquiries, call 715.247.3433, visit our website, or follow us on social media.

 

Schwing Bioset FSP 503 Screw Press Dewatered Alum Sludge

 

Tags: Water Treatment, Screw Press, Dewatering, Water Plants

Screw Press and Bioset Demo Leads to Treatment Plant Expansion

 

Written by Tom Welch, September 10, 2015

The Springfield, IL, Metro Sanitary District (SMSD) Sugar Creek Plant is going to be expanding over the next two years.  They currently have no dewatering capability and they treat their liquid sludge with lime and liquid land-apply on their own fields onsite at the plant.  In June of 2013, Schwing Bioset was invited to run a dual demo of their screw press and Bioset systems.  The pilot study was conducted for two weeks where the Waste Activated Sludge (WAS) was dewatered with the screw presses and then converted to a Class A EQ product through the advanced alkaline stabilization Bioset process.  Crawford, Murphy, and Tilly Engineers coordinated the pilot study for the District.

Prior to the pilot study, the plant operations team was leaning toward using belt presses for their future dewatering needs.  They had familiarity with belt presses and they were concerned that screw press technology did not have the capability to meet their requirements of 2660 dry pounds per hour without having to install a large number of screw press machines.  They were basing their concerns on historical screw press throughput capability based on their market research.

Springfield_Demo_Image_1-1

(Pilot Study Setup at SMSD Sugar Creek Plant)

During the pilot study, the Schwing Bioset team brought their FSP 600 screw press machine to dewater the partially aerobically digested WAS.  The goal was to dewater the material to the highest percent solids, with an excellent capture rate, and also with the least amount of polymer consumption.  The dewatered product would then be passed along to the mobile Bioset operation, which is an advanced alkaline stabilization process that can produce a Class A EQ Biosolid end product that can be utilized as a fertilizer or a soil amendment. 

The first week of the demo was utilized to optimize the screw press performance, and the second week to monitor continued performance of the screw press while utilizing the Bioset operation to produce a Class A EQ product. The purpose of this was to monitor the product over a couple month period to determine the stability of the Class A EQ product at the Springfield plant.  Over the two weeks, the FSP 600 screw press unit produced a dewatered product of 30% solids on average, even while operating the machine at 130-150% of design throughput capability.  After polymer optimization, the end result was realized with 14 pounds of active polymer per ton and the capture rate was above 95% during the entire two week period.  During the second week of the pilot, the Bioset system was utilized the entire time and was successful in producing the Class A EQ product.

Based on the successful results of the pilot, SMSD gave Crawford, Murphy, and Tilly the direction to design the new biosolids handling facility to include two high-performance screw presses, each capable of dewatering 1330 dry pounds per hour.  Although they liked the simplicity of the Bioset Class A operation, they were uncertain if the need for Class A was justified for the new facility.  They settled on a Class B Bioset system that utilizes all of the components of the Class A design, except for the reactor.  Space was left in the building to install the reactor in the future should Class A become necessary.  The job bid in December of 2014 and Schwing Bioset received an order for the two high-performance screw presses and the Class B alkalization system in early 2015. 

These FSP 1102 screw presses showcase the capabilities of high-performance screw presses and offer larger plants an appealing alternative to traditional belt filter press or centrifuge dewatering.

To learn more about our screw presses, Bioset process, and/or this project specifically, contact a Schwing Bioset Regional Sales Manager, call 715.247.3433, email us, and/or visit our website here.

Springfield_Demo_Image_2-1

(Class A EQ product at 44% solids)

 

 

Tags: Class 'A' Biosolids, Bioset Process, Alkaline Stabilization, Class AA/EQ Biosolids, Biosolids, Wastewater Treatment, Screw Press, Dewatering

We Dewater Water Plants Too – Part One Ferric Sludge

 

Written by Tom Welch, July 7, 2015

Although primarily thought of as a technology for dewatering in wastewater plants, Schwing Bioset’s screw press has also been successfully applied in water plants.  We recently completed an installation of a screw press at the Davidson Water (ferric sludge) water treatment plant. 

Take a look at part one of a two part article on the successful application of Schwing Bioset’s screw press technology on ferric and alum sludge generated by water treatment plants.

Davidson Water, Inc. is located in Lexington, North Carolina, and is a large membership cooperative with a plant capacity of 35 million gallons per day.  Upon successful pilot trials, Davidson Water selected the Schwing Bioset FSP 602 machine for dewatering its full scale operations.  They are now running at about 85% throughput and obtaining 27-30% solids, with greater than 95% capture rate and less than 20 pounds of active polymer per ton.  Recent operating conditions have achieved dry solids contents as high as 38%!

Davidson Water’s current operations are surpassing the performance demonstrated during on-site pilot trials that were completed almost two years ago and are exceeding their expectations.  Take a look at the photos below of the Davidson Water installation, which show the simple set-up and exceptional performance. 

Stay tuned for Part Two of 'We Dewater Water Plants Too' on dewatering the alum sludge for a water treatment plant in South Carolina.

To see video of the Screw Press in action or learn more about it, contact a Schwing Bioset Regional Sales Manager, call 715.247.3433, email marketing@schwingbioset.com, and/or visit our website here: SBI Screw Presses.

 

Davidson_Water_1 Davidson_Water_2 Davidson_Water_3

Tags: Water Treatment, Screw Press, Dewatering, Ferric Sludge, Water Plants

Schwing Bioset Exhibiting at WEF Residuals and Biosolids Conference

 

June 4, 2015

Schwing Bioset, Inc. will be exhibiting at the 2015 WEF Residuals and Biosolids Conference in Washington, DC, on June 8th and 9th.

Please be sure to stop by our booth (#106) while you're on the exhibit floor.

 

Visit the conference website to view the event details and exhibition map: http://www.residualsbiosolids-wefiwa.org/

Here is the Schwing Bioset listing for the show: http://app.core-apps.com/15rbwe/exhibitors/d4d3b4f759e0e3a5025efd0a3d0e4fc4

Learn more about our Bioset Process and Class 'A' Biosolids, Dewatering Equipment, Pumps, and other products here: http://www.schwingbioset.com/products

 

If you'd like to meet with one of our team members, please contact marketing@schwingbioset.com for the names of the team members who are attending the show.

We hope to see you there!

 

Bioset_Video_Screenshot

 

Tags: Class 'A' Biosolids, Bioset Process, Events, Biosolids, Wastewater Treatment, Pumps, Dewatering

Screw Press Adds Dewatering to Schwing Bioset Capabilities

Schwing Bioset is proud to announce the addition of a screw press dewatering system to their family of products.

 

Somerset, WI (PRWEB) January 19, 2013

A natural progression enabling clients to work with one dynamic solution provider to solve their biosolids management issues, Schwing Bioset has added Screw Presses to their family of products enabling them to help clients from dewatering to biosolids disposal.

Schwing Bioset Screw Press Dewatering Systems offer the features you want and performance you can count on. From low power requirements and unattended operation to high solids and high capture rates Screw Presses provide exceptional performance at a fraction of the energy and maintenance costs of other technologies.

With eleven models, each built to the same exacting standards, Schwing Bioset offers the widest range of model sizes available and can offer its customers, unlike competing technologies, the same high level of performance from top to bottom in the product line.

With over 65 machines in service and the Schwing Bioset name standing behind the technology for on-going support, municipalities now have a new option to provide superior dewatering performance for their biosolids.

screw press dewatering system

Tags: Biosolids, Schwing Bioset, Screw Press, Dewatering

Managing Cost, Air Quality and Odor Control with Schwing

Case Study: Ellsworth, WI

The West Central Wisconsin Biosolids Facility (WCWBF) is a regional biosolids processing facility in Ellsworth, Wisconsin, serving Ellsworth and over 20 neighboring communities. The biosolids are dewatered by centrifuges to 20-24% total solids. The dewatered sludge enters an alkaline stabilization system that mixes the sludge with lime and fly ash to yield a Class A product. The treated biosolids are stockpiled in a 37,000-square-foot covered storage building, and beneficially reused semi-annually by local farmers.

In 2008, WCWBF decided to upgrade the lime stabilization process, with the main goals being to contain cost and maintain air quality and odor control. The existing mixer used open hoppers; between that and the fly ash, the system generated a lot of dust. Furthermore, the facility received periodic complaints from neighbors about the odor.

WCWBF chose a Schwing-Bioset system employing a closed hopper, screw conveyors, and pressurized piping system to contain dust and odors. To avoid costly contract hauling charges, WCWBF had to achieve demolition of the old system and installation of the new Schwing-Bioset system within 10 days of shutting down the old system. Demolition and preparation took three days; Schwing Bioset's team installed the new equipment, including the electrical, within the remaining seven days.

With a few minor modifications to adapt it to the winter weather, the Schwing-Bioset system has performed within expectations since commissioning, achieving its goals of managing cost, dust, and odors.

Tags: Class 'A' Biosolids, Bioset Process, Alkaline Stabilization, Biosolids, Dewatering