News from Schwing Bioset

Pump Performance is Key in Nevada Mine Dewatering Operation

 

Schwing Bioset Application Report 16, Turquoise Ridge, NV

Written by Larry Trojak, Trojak Communications

Version also published in Engineering & Mining Journal 

 

Water is a critical element in any mining effort, aiding in everything from dust suppression to actual material recovery. Encountering larger volumes of it, however, can also be one of the biggest hindrances to mine production and efficiency. And when that water contains solids with trace amounts of gold, removing those solids is suddenly a very different procedure, changing from a material disposal effort to one with a focus on material recovery. Such is the case at the Turquoise Ridge gold mine near Golconda, NV, where a pair of Schwing KSP-50 sludge pumps are being used to get dewatered material to a site where its highly-valued content can be recovered. The fact that the area is 1,800 feet straight up and the material has a 40% solids content has taxed such previous efforts. However, the system currently in place has been performing flawlessly for better than nine years now, testimony to both its design and the heartiness of the equipment itself.

 

Water, Water, Everywhere . . .

The mine at Golconda, an almost decade-long joint venture between industry giants Barrick and Newmont Mining, sits on 50 square miles and has been in operation under various names and ownerships since the early 1900s. With a mine that size (current annual gold outputs at TR are in the 200,000 ounce range), encountering water is a normal part of the process and Turquoise Ridge is no exception, according to Bill Davenport, dewatering supervisor.

“It’s not uncommon to hit ‘pods’ of water or underground streams within the fractures of the rock; it is all naturally occurring water,” he says. “We have a huge development drift in the very bottom of the mine on the main decline drift and at the brow of that drift there is water coming out that just runs down the ramp. There are also areas on another drift in which we were drilling and blasting in advance of utilities and hit a pod that started releasing hot water at a rate of about 40 gallons/minute. Today, throughout the mine, we are pumping out between 650 and 700 gallons a minute—more than a million gallons a day.”

Schwing Bioset Mining Pump 

Waste? Not!

Previous efforts to deal with water issues first included using basic sumps to remove it. Mine personnel would then simply muck the residual solid material, dry it out in various drift locations and haul it to the MHD (material handling drift) to be shipped out of the mine. That all changed when it was discovered that the waste product had value.

“Back then, the residual material wasn’t being assayed for gold value so it was seen as nothing more than waste,” says Davenport. “When it was found to have a decent ore content, the whole process had to be revised. One effort included shipping the discharge water directly to a treatment process facility where it was treated for arsenic and other impurities. There, it was stored in a huge 500,000 gallon thickening tank, the solids were collected and sent on to the tailings facility using underflow thickener pumps.”

While that thought process was sound, adds Davenport, the decision to pump directly to the surface, rather than cascade-pump it from level to level, proved too much for that type of equipment. “When the pumps would fail—which was often—we would flood,” he says.

Around that same time, a hydrology study conducted by an engineering firm warned that, because of the inevitability of hitting more and more large pockets of water, a serious process upgrade was needed.

The JV team regrouped and opted for a design with clarifiers to settle out the dirt and decided that a positive displacement pump would be the best solution to handle a push of that vertical distance. In 2004, a major upgrade to the dewatering effort—including installation of a pair of 200 hp Schwing Bioset KSP 50 HDV sludge pumps—took place and has been at work ever since.

 

Positively Beneficial

Today all the water from the mining effort at Turquoise Ridge is captured through a series of multi-location, multi-level sumps and drain holes and shipped to either permanent pump skids (with 4” X 3” centrifugal pumps) or to 8” X 6” permanent pump stations. From there it is directed to a trio of 16,000 gallon clarifiers located an area in a drift adjacent to the main dewatering station. The clarifiers act as thickeners allowing the solids in the dirty water to settle out. The clear water is decanted into two other larger 19,000 gallon clear water basins. Half of that clear water is sent on for subsequent treatment and routed to rapid infiltration basins in nearby Valley; the remainder is re-used in the mining operation. Infiltrated water meets Federal drinking water standards.

“At that point, we have to dispose of the solids from the clarifiers, and the pumps make that possible,” says Davenport. “After leaving the clarifiers, that material is about 20% solids content and it has to be pumped through 3-inch pipe almost vertically for a distance of about 1,900 feet. Just after it reaches the collar of the shaft, it is discharged into a 12-inch pipe and carried roughly a mile and a half to the tailings area. That’s an amazing load to place on any piece of equipment”

When the solids content of the material gets too high for effective pumping, onsite personnel simply introduce water to the mixture using a port at the pump’s suction box, lowering the solids and enhancing flowability. Davenport says they run the pumps at the start of each shift for about three hours, and move, on average, about 15 tons of material in a 24-hour period. While performance is an obvious attribute, he is equally pleased with the pumps’ low maintenance demands, citing only a periodic change of poppets, pressure seats and ring to keep them in “fighting” shape.

“By comparison, over at one of our sister mines, we have duplex pumps working in support of autoclaves and the slurries they create. Those are extremely expensive pumps and the maintenance demands associated with them are brutal—that’s a tough one-two punch. Because mines are all about production, they have those pumps working continuously at maximum speed and, as a result, are constantly replacing pistons, rings and so on. Granted, we are only doing a fraction of the volumes they are, but we are pumping against 800 p.s.i. which is huge. As far as reliability and cost to operate, I’m certain our pumps are hands-down a better investment.

Schwing Bioset Underground Mining Pumps 

Additional Recovery

As mentioned above, even the waste product from a mine contains gold—in this case, about ¼ ounce per ton—so material that has been placed to the tailings area is far from ready for disposal.

“The material that the pumps moved out to those 13 cells is dug out and spread to dry prior to shipping it off to Newmont’s Twin Creeks facility to start the process of final recovery. At that point all the gold will have been recovered,” says Davenport

Mining is a tough application on any piece of equipment, but especially so on one that is regularly dealing with high operating pressures and abrasive material. Davenport cites the reliability of the equipment and the solid support they’ve received since installation almost a decade ago as key reasons for that ongoing success.

“My guys maintain them well; in this business you have to,” he says. “But these pumps have been extremely good at providing support to our operation. This mine is growing and its growing to a point where there might be some changes made in a couple of years. There is talk about adding another dewatering site in the lower part of the mine and installing some additional sludge pumps. I can’t say what will happen at that point, but there’s no denying we’ll be thinking about the outstanding performance we’ve gotten from the pumps.”

 

Contact us to learn more about our pumps for mining, municipal, or industrial applications.

 

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Tags: Sludge Pumps, Pumps, Mining, Mining Pumps

Diversity, Equipment Longevity are Key for New York Wastewater Plant

 

Schwing Bioset Application Report 15, Glens Falls, NY

Written by Larry Trojak, Trojak Communications

Version also published in TPO Magazine, August 2013

Dewatering at WWTP

While most wastewater treatment plants focus their efforts solely on the material collected from within their own municipality, some choose-often for economic reasons-to supplement that volume with outside waste. After a major expansion in the late 1980s, and an upgrade in the mid-1990s, the city of Glens Falls (NY) Wastewater Treatment Plant found itself in just such a situation and opened up its facility to non-system waste. Today, drawing from a wide range of sources, the plant accepts an equally broad range of materials including: grease trap waste, sanitary holding tank waste, septage, sewer cleaning debris and wastewater sludge-both liquid and cake-from off-site facilities. That product diversity, coupled with impressive long-term equipment performance, has helped the plant remain viable in serving the upstate New York city and surrounding areas.

Legacy Lives On

Located on the Hudson River about 45 minutes north of Albany, Glens Falls is a picturesque small city, home to just under 15,000 residents, and a thriving base for the medical device and medical services industries. The city was also the site of a huge pigment manufacturing facility that was shut down in the 1980s, but left a legacy of contaminated soil in its wake. Today, nearly three decades after its closing, wastewater from the site’s groundwater treatment and collection system is still being processed at the Glens Falls WWTP, according to Jason Vilander, the plant’s maintenance manager.

“That pigment plant was actually a driving force in an expansion that took place here in the mid-‘80s,” he said. “A lot of water is used in chemical and dye work—water that couldn’t simply be discharged to the river—so the plant was designed to accommodate that additional wastewater volume. That expansion allowed us to move to activated sludge treatment and prompted installation of a fluid bed incinerator. Unfortunately for us, the pigment plant shut down during the latter part of our expansion, leaving us with a good deal of extra capacity.”

Since that time, Glens Falls WWTP has had an ongoing contract to accept and treat water from the groundwater collection system from the pigment plant site.

Filling the Void

Needing to fill the excess capacity left by the pigment plant’s untimely closing, Glens Falls WWTP began to actively seek companies or organizations looking to outsource their wastewater and waste product treatment needs. To say those efforts were a success would be an understatement. Today, the plant serves a fairly localized geographic area, taking in material from the town of Queensbury (six of its seven districts), as well as the Village of South Glens Falls, including the business centerpiece, Moreau Industrial Park.

But, because they were aggressive in reaching out to businesses throughout the region, they now also count many of them as customers. 

“We’ve had success in some unlikely places,” says, Vilander. “Most of our liquid sludge, for example, comes out of Vermont. That includes some of the larger ski resorts as well as many of the treatment plants from other towns and villages—plants that don’t have drying beds or digesters or any other means to take product through the final steps needed for it to be safe for disposal. So we provide that last step for them.”

Volumes are also supplemented by outside cake haulers, including regional correctional facilities such as Comstock Prison and the Washington County (VT) jail.

“These facilities all have their own wastewater treatment systems, complete with belt presses, which allows them to generate a cake. But that’s as far as they can go with it. So, twice or three times a week, they send us five tons of cake in a single-axle dump truck, and dump it onto a pad. We then use a pay loader to load that cake into a receiving station where it is stored until we have the time and manpower to incinerate it,” he adds.

Three Decades of Sludge

The benefits gained by reaching out for additional material would be a moot point were Glens Falls unable to effectively incinerate what it collects. Vilander says the equipment in place in many parts of the facility has amazed him in both its capability and its longevity.

“A good case in point would be our sludge pumps,” he says. “We had a pair of Schwing KSP-5 sludge pumps that were installed during that first plant upgrade in the 1980s. Those pumps—which were among the first made by Schwing for this market—have been outstanding for us, given what they’re asked to do. They were replaced just a couple years ago after nearly three decades of pumping. And mind you, they were replaced not because of wear issues, but because our volumes had grown so much over the years that we needed to upsize.”

He adds that the pumps’ impressive performance is made even more so given the fact that one of the critical steps in their routine maintenance was often overlooked for being “too inconvenient.”

“I’ve always felt that keeping the water in a pump’s water box clean is second only to keeping the hydraulic fluid clean,” he says. “Unfortunately for us, in the prior expansion, a grate, which allowed personnel to walk around the belt presses, was installed right over the top of the pumps’ water boxes, making access difficult. As a result, the water was changed far too infrequently. I’m still amazed at how well those pumps worked—and how long they performed for us—even with that lapse in an important operating procedure.”

With This Ring

Schwing Bioset Sludge Piston Pump at WWTP

With the upsizing to a larger pair of sludge pumps (Schwing KSP-10s), Glens Falls has increased their pumping capability to deal with the growth in biosolids handling at the plant. The new pumps take cake that has been dewatered to about 24%-26% solids and route it for incineration where a 32-ton load of cake (an 18-wheeler full) can be reduced to 100 pounds of ash. Moving that high solids content says Vilander, is helped by the addition of a “slip ring,” or pipeline lubrication system, a feature that injects a thin film of water to reduce friction loss in the pipeline and lower pipeline operating pressures—in some cases by more than 50%.

“We work so hard to get all the water out, so it seems a bit contradictory to be putting some back in," he says. "But, because we’re running these slip rings at about 20-30% of their capacity and they come on for only a matter of seconds, we are adding no more than three gallons per hour. So the amount of water added is minimal and pales by comparison to the improvement in throughput and the fuel savings we achieve with the drier sludge cake,” stated Vilander.

Additional benefits provided by the newer pumps include a much greater degree of versatility. Because the pumps are PLC-controlled, Vilander and his crew are able to have them run in several different modes including: “pressure,” tracking” or “manual.” That means they now have the capability to automatically control the speed of the hopper screws and the pump itself.

“With the old pumps, we could adjust our pressures a bit to get the speed we needed, but we couldn’t get independent control of both components—the screws and the pump, says Vilander. "Now we can and it’s made a huge difference. Because the pumps run nice and slow—and quiet— I’m not even seeing the level of maintenance that I had with the old ones. I can see these outlasting even those previous workhorses,” said Vilander.

Grease is the Word

The ultimate destination for all the cake processed through Glens Falls is a fluid bed incinerator which 18’ 3” in diameter with a height of 44’ 9”. The unit is designed to maintain an effective operating temperature of 1500°F and uses the cake itself as the primary fuel source. According to Vilander, if the cake is dry enough, it will reach an autogenous state and burn without an additional fuel source.

“However, if it’s too wet, or does not have enough VOC in it, we have to add BTUs through an alternative heat source which, in the past, was fuel oil. While the new belt presses gave us a much drier cake, we still found ourselves having to rely upon the fuel oil and the costs associated with it. As part of an overall cost savings move, we installed a two part grease system consisting of a concentrator and a storage tank,” said Vilander.

Doing so not only dramatically reduced the operational costs at Glens Falls; it also gave area businesses a way to efficiently dispose of grease from their operations. Now, the septage haulers simply bring the grease to the plant, pay a disposal fee and it gets concentrated, thickened and burned.

“Occasionally we will get a load of grease with wastewater added to it which has to be treated differently. So it goes into our storage tank where it is mixed and pumped up to our belt presses, combined with the cake and moved—once again using the Schwing pumps—out to incineration. The grease, which was once a waste product, is now both a fuel source and a small revenue stream,” said Vilander.

Better in the Long Run

If it sounds as though Vilander is a proponent of piston-style pumps versus their progressive cavity (PC) counterparts, it’s because he is, and that feeling is based on experience he’s gained at Glens Falls.

“We had an emergency situation arise a while back in which the incinerator was down and we had to take some steps to effectively store the cake until it was back online. We stockpiled it onsite but then had to find a way to re-introduce it into the system when we were up and running. So we teamed up a conveyor and a PC pump as sort of a makeshift solution. That experience taught me that, while PC pumps are certainly a lot less expensive; they do not handle grit at all and, given what we went through then, won’t last nearly as long,” said Vilander. He adds that they’ve never done a study to determine the total life cycle ownership/operation cost of their piston pumps versus that PC unit, but says he wouldn’t be surprised at all to find it costs more to run the PC pump.

“Our piston-style pumps were more expensive up front but we know they will provide decades of good service. I think we’ve already proven that,” said Vilander.

 

To download the entire #15 application report for Glens Falls, NY, click here.

To learn more about Schwing Bioset, our products and engineering, or this project specifically, please call 715-247-3433, email marketing@schwingbioset.com, view our website, or find us on social media.

To view a version of this story published in TPO Magazine, click here.

 

Tags: Sludge Pumps, Piston Pumps, Wastewater Treatment, Pumps, Dewatered Sludge Cake

Schwing Bioset 2012 KSP Service Seminar

May 2012

KSP 2012 Service Seminar

Schwing Bioset is proud to announce the dates for our KSP Service Seminar. The seminar will be held on May 7th-11th, 2012. A second class maybe offered on May 14th-18th, depending upon demand.

Get the most out of your equipment. Attend the Schwing Bioset Service Seminar and receive the best training in the industry. With both classroom and hands-on instruction you will learn how to properly use and maintain your equipment. The classroom portion of the seminar is held in our training center with working models and cut-a ways of components. Our hands-on facility features several pieces of working equipment students can interact with.

The cost for the seminar is $1195.00 USD. The fees do not include airfare, ground transportation to or from the airport, lodging or evening meals. Payment must be received prior to enrollment.

Click to download the registration form!

 

KSP Service Seminar

Tags: Sludge Pumps, Class 'A' Materials, KSP Service Seminar, Poppet Valves, Screw Feeders, Hydraulic Pumps

What's Your Vector?

Biosolids can attract “vectors,” which are basically any living carrier that transmits an infectious agent (think ticks, mosquitoes, fleas, some kinds of flies, etc.). Meeting EPA Part 503 standards for Class A or B biosolids of various types requires that the biosolid meets at least one (sometimes more) of the ten vector attraction reduction options listed below:

Option 1. Reduce the mass of volatile solids by a minimum of 38%.

Option 2. Demonstrate vector attraction reduction with additional anaerobic digestion in a bench-scale unit.

Option 3. Demonstrate vector attraction reduction with additional aerobic digestion in a bench-scale unit.

Option 4. Meet a specific oxygen uptake rate for aerobically treated biosolids.

Option 5. Use aerobic processes at greater than 104°F (average temperatures 113°F) for 14 days or longer (e.g., during biosolids composting).

Option 6. Add alkaline materials to raise the pH under specified conditions.

Option 7. Reduce moisture content of biosolids that do not contain unstabilized solids from other than primary treatment to at least 75% solids.

Option 8. Reduce moisture content of biosolids with unstabilized solids to at least 90%.

Option 9. Inject biosolids beneath the soil surface within a specified time, depending on the level of pathogen treatment.

Option 10. Incorporate biosolids applied to or placed on the land surface within specified time periods after application to or placement on the land surface.

The Bioset process can help you achieve these options for your wastewater treatment. Contact Schwing Bioset for more information. For a more detailed explanation of these vector attraction reduction options, refer to the EPA’s Part 503 Rule, Chapter 5 [PDF].

vector

Tags: Sludge Pumps, Biosolids, Wastewater Treatment

Case Study: Stewartstown, PA

piston pumpsThe Stewartstown Sewage Treatment Plant (STP) is owned by the Stewartstown Borough Authority of Stewartstown, PA. The plant experiences flow at an average rate of 0.625 MGD (millions of gallons per day) plant with MBR (membrane bioreactor) treatment. Sludge is dewatered with a 1.5m belt filter press that produces 16-17% solids. Before working with the Bioset process, the Stewartstown Sewage Treatment Plant's disposal strategy typically consisted of processing liquid sludge at a neighboring facility. Alternatively, dewatered sludge was hauled to a landfill.

Upon recommendation of their consulting engineer, the Borough investigated Class A technology to take advantage of more disposal options. A thermophilic digestion process was considered. However, given the relatively small size of the plant, this option was rejected for requiring the investment of too much capital and manpower. The Bioset process offered a low-cost Class A option that could be integrated into the plant operation. Alkaline stabilization was designed into an overall plant upgrade and put out for tender in 2007.

The layout flexibility of the process was again crucial as the mixer, pump, power unit, and reactor were engineered to fit into a single garage bay, with reactor discharge pumping to an adjacent garage bay to load the truck. The process was operational by the end of 2007.

Today, using the Bioset process, the Class A biosolids are disposed of at two agricultural sites. The farmers are responsible for spreading the product. The farmers have reported positive results with their crop yields and have not had any odor-related complaints. Pennsylvania regulations permit spreading Class A biosolids year-round, so there is no need for material storage through the winter.

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

From Food to Fuel

In another Wisconsin-related story, Treatment Plant Operator Magazine had an article recently about the Milwaukee Metropolitan Sewerage District (MMSD), which has been making organic fertilizer-called Milorganite and sold across the country-out of waste activated sludge for 85 years, and recently started generating and using digester methane at its South Shore Water Reclamation Facility.

The plant processes sludge in its anaerobic digesters. The gas fuels a 5-MW cogeneration system that provides much of the site's electricity as well as heat for the digestion process.

One of the interesting things about this process is that the district is trying to maximize gas production (which amounted to about $800,000 worth of energy last year, based on market prices; when natural gas prices were higher in 2008, the district produced $1.8 million worth) by urging people to grind food waste in garbage disposals and return it to the district via wastewater rather than throw food waste in the garbage and have it hauled off to the landfill. This is part of their Food Is Fuel public information effort.

foodisfuelcat

The Food is Fuel program notes that the average family of four generates nearly 2,000 lbs. of food waste per year. Food waste is mostly water, so it makes sense to grind it and send it to the water reclamation plant. Here's how it works: food scraps produce methane gas that MMSD captures and converts to power that runs the plant. Those food scraps are also used to make fertilizer.

The methane production/use program has been so successful that MMSD is researching ways to expand it.

Tags: Sludge Pumps, Wastewater Treatment

Schwing Bioset Introduces Its New iKSP Piston Pump

October 2007

Schwing Bioset proudly introduces its new iKSP piston pump. Built with the same rugged durability of the KSP series pump, the iKSP is rated for:

  • Belt Filter Press biosolids ranging from 6% to 22% dry solids content
  • Operating pressures up to 400 psi
  • Outputs up to 35 gpm

The iKSP is offered as a cost effective alternative to high maintenance progressing cavity type pumps and features the same long wear part lives and simplistic maintenance procedures as the original KSP series pump.

Tags: Announcements, Sludge Pumps, Pumps