Dredging World News Blog

Lagoon Maintenance Dredging every Decade

Posted by Laura Fleming on Thu, Mar 21, 2013 @ 11:03 AM

SRS Crisafulli has discovered the Rural Water Association.  This winter, Troy Fercho, Frank Robinson, Tristan Hoff and I attended shows in North Dakota, Montana, Minnesota, and Idaho.   At these Rural Water Association Trade Shows, we promoted SRS Crisafulli's dredge equipment and rental services to assist communities in managing the long term, low cost resource of their wastewater lagoon systems. 

Flump Dredge System

When lagoon operators use proven, successful, operating and maintenance procedures, Wastewater Lagoon Plants can get in compliance, and can stay in compliance.  Many lagoons have been in service for 30, 40, or 50 years.  Lagoons should be desludged every 8 to 10 years for optimum performance.

One of our dredge systems, the remote controlled Flump Dredge System, pictured here, is an electric, unmanned system that is available for sale or can be rented directly by a facility or by a contractor.  All of our dredge systems are made in the USA – in Montana to be exact. We provide installation and operator training for dredge sales anywhere in the world, and for rentals anywhere in the USA and Canada.

What have we learned at the Rural Water Shows?  One of the high notes of the Great Falls conference was meeting Steve Harris, an independent consultant from Arizona, who has provided lagoon optimization and troubleshooting services for over a decade.  Steve gave several presentations on lagoon troubleshooting at the Montana Rural Water Association convention in Great Falls.  

How to Upset a Wastewater Treatment Plant

Steve Harris put a little bug in my ear about the impact of methamphetamine laboratories on wastewater treatment lagoons.  Quick investigation produced a similar article in the December, 2012 issue of Treatment Plant Operator, by wastewater treatment plant Laboratory Detective, Ron Tygar, entitled, "Knowing What’s Coming." Ron writes:  “Industries are not the only sources of discharges that can upset treatment plants.  Residential abusers can have big impacts, too.”  In his article, Ron, gave two specific examples of residential sewage abusers - deep fat turkey fryers, and methamphetamine labs.

In the first case, residents sometimes face the dilemma of what to do with 7 to 8 gallons of used cooking oil once the Thanksgiving holiday has passed. Some ingenious homeowners have discovered that the 3-inch PVC clean-out cap sticking up in the yard is conveniently connected to the local sewer system. 

In the second case, the high levels of waste ammonia discharged into the sewer system along with other hazardous substances create a high-strength, or even toxic waste to the fragile micro-organisms.

Troubleshooting your Lagoon

Steve is the author of Wastewater Lagoon Troubleshooting - An Operators Guide to Solving Problems and Optimizing Wastewater Lagoon Systems.  Steve's textbook charts eight general problems in lagoon management: 

     (1)  low dissolved oxygen,  (2)  toxicity, (3)  odors, (4)  low temperature, (5)  high coliform, (6)  high BOD (biological oxygen demand), (7)  TSS Control (total suspended solids), and my favorite, (8)  “Short Circuiting” which refers to hydraulic inefficiencies that allow wastewater to exit a lagoon over a time shorter than necessary to completely stabilize it. 

In terms of the potential value to lagoon operators of a dredging resource, removing sludge scores a 7 out of 8.  Steve offers at least five strategies for each of the eight major issues on the way to optimum lagoon performance and compliance.

There are many fine points in managing wastewater systems.  Our interest as a supplier of "sludge removal systems" is to support the longevity and efficiency of lagoons as operating systems.

As Steve Harris writes in the preface to his textbook, “The knowledge concerning diagnosing and solving operational problems in wastewater stabilization ponds has been greatly expanded over the last twenty years.  Many papers have been published in scientific journals and several excellent books have been written on the subject of wastewater lagoon systems.  Years of consulting with lagoon operators across the US, Canada, Mexico and Central and South America has shown me that little of this valuable information ever reaches lagoon operators.”

Another resource that addresses that same knowledge gap is the Maine Lagoon Systems website, which has a  mission is to promote clean water resources through the enhanced communication of wastewater lagoon system operators in the state of Maine and beyond. This website provides an online presence in which operators of lagoon systems can network with each other on various issues of wastewater treatment relative to today's demand of a clean water environment.

A technical note from the Maine Lagoon Systems offers the following:

It has been reported that as many as 60 percent of the BOD5 (The amount of dissolved oxygen consumed in five days by bacteria that perform biological degradation of organic matter) violations nationally may have been caused by nitrification in the BOD5 test rather than by improper design or operation (Hall and Foxen 1983). Consequently, millions of dollars may have been spent needlessly on new treatment facilities.

To decide if you too want to meet Steve Harris, a 2009 lecture is available on YouTube.

H&S Environmental is committed to helping you get better performance from the wastewater lagoons you're already using.  Their goal is to provide wastewater lagoon operators with practical, easy to use and cost effective tools to solve their toughest wastewater lagoon challenges.  H&S Environmental is committed to the belief that wastewater lagoons are capable of producing high quality effluents...effluents that will consistently meet tougher new permit limits.  Some of the chief problems with wastewater lagoons are operational, but many lagoon problems are the result of design deficiencies that can be fixed.

To learn more about Lagoon Dredging or
to inquire about dredge rentals or purchasing options...
Contact us Now!

 

 

Steve Harris, H & S Environmental

Maine Lagoon Systems

Rural Water Association

Treatment Plant Operator

Topics: crisafulli, dredge, srs crisafulli, lagoon dredges, dredging system, dredging equipment rentals, lagoon, Treatment Plant Operator, Municipal dredging, biosolids, Montana, water treatment plant, wastewater treatment plant, sludge, maintenance dredging

SRS Crisafulli Explores Dredging and Hydropower

Posted by Elizabeth Kaiser on Wed, Jan 25, 2012 @ 08:01 AM

By Elizabeth Kaiser, SRS Crisafulli Marketing Manager

Energy production and consumption worldwide is influenced by many factors.  Resource availability, economic activity, population growth and environmental regulations, for instance, all affect the types of energy production that may be available to consumers.   One of the cheapest methods of energy production is hydroelectric power.

Last spring’s press release by the U.S. Department of the Interior, Departments of Energy and Interior Announce $26.6 Million in Funding to Develop Advanced Hydropower Technologies, announced  “funding for research and development projects to advance hydropower technology, including pumped storage hydropower.”  Hydropower is a sustainable and clean power generating process.  “These funding opportunities will help unlock innovative approaches to hydropower development that emphasize sustainable, clean power generation while reducing environmental impacts.” 

What is the hydropower process?  In short, falling water is passed through a hydroelectric generator to produce electricity. Another hydropower process involves what is called “pumped-storage”. As explained by the Tennessee Valley Authority, “A pumped-storage plant uses two reservoirs, one located at a much higher elevation than the other.  During periods of low demand for electricity, such as nights and weekends, energy is stored by reversing the turbines and pumping water from the lower to the upper reservoir.”

Watch this YouTube video "Hydroelectic Power - How it Works"

 

How is dredging part of this scenario?  The most serious technical problem for hydroelectric dams is accumulation of silt which reduces the water storage capacity of the dam.   Reduced storage capacity limits both electricity generation and the availability of fresh water for downstream uses.  Periodic maintenance dredging removes silt deposits from the dam reservoir and restores water storage capacity, thereby allowing the hydroelectric dam to function more effectively. Periodic dredging can reduce potential negative impacts on fresh water availability without interrupting energy production.

 

Want to learn more about hydroelectric dam dredging?  Contact us.

Watch or download Crisafulli dredge videos.

Subscribe to this blog’s RSS feed for the soon to be announced Rotomite 6000 C Series Dredge.


Topics: Dredges, crisafulli, dredge, dredging, srs crisafulli, dredging abrasive materials, lagoon dredges, dredging system, dredging and pumps, lagoon, rotomite 6000c, Hydraulic dredging

Dredging and Shoreline Remediation

Posted by Elizabeth Kaiser on Wed, Dec 07, 2011 @ 08:12 AM

By Elizabeth Kaiser, SRS Crisafulli Marketing Manager

Many situations can complicate a shoreline’s integrity.  These can range from flooding, hurricanes and man-made disasters and can even include aquatic harvesting and human recreation.  Making efforts to protect a shoreline from these intrusions helps protect economic and recreational interests.  Shoreline remediation is an investment in the overall economic and natural habitat of a community.

As defined by the Erosion Control Technology Council (ECTC), Sediment Control is A practice that captures soil particles on site that have been detached and moved by wind or water.   While different methods and practices are used when it comes to shoreline remediation and sediment control we will examine a specific method, dredging and shoreline remediation.

Let’s look at the Southwest Mordecai Ecosystem Restoration Project or “SWMER”.  According to the SWMER Project Scope found at mordecaimatters.org, “The SWMER Project focuses primarily on several rapidly eroding areas on the southern rim of Mordecai Island.Southwest Mordecai Ecosystem Restoration Project

SWMER complements Mordecai Land Trust’s wave barrier project with the Army Corps of Engineers which involves the planned installation of a barrier off the western coast of Mordecai north of the SWMER area.

The SWMER project required careful planning on the part of Mr. Jim Dugan, President of Pond Recovery Services of Hainesport New Jersey and contractor for the SWMER project.

Jim Dugan has owned and operated dredges for many years and has used them in conjunction with Geotubes for the purposes of shoreline remediation.  He has contracted his restoration services throughout New Jersey and surrounding waterways including the Chesapeake Bay.  President of the Mordecai Land Trust, Jeffrey Hager, wrote of Jim Dugan, regarding the SWMER project, “He (Jim Dugan) proved to be an extremely competent and conscientious field manager,…”

Jim Dugan describes the SWMER project as a material handling challenge.  “We had to move 900 tons of sand to an island in the bay.”  As described in the Mordecai Matters Newsletter, Winter 2010 issue, SWMER involves the installation of close to 600’ of huge sand-filled fabric tubes called Geotubes, slightly off the south-western edge of Mordecai Island.  “The erosion has been severe here and the hope is to stabilize this fragile part of the Island and encourage the deposition of grasses and other organic materials between the island’s edge and the two long sections of Geotube.

Jim explained that they couldn’t use the sand from the bay so they transported 900 tons of clean sand from a nearby quarry by truck.  But how do you get the sand to the island?  “You have to pump it.”  Jim said there were 2 major challenges involved.

  1. Don’t plug the pipeline with too much sand
  2. Water/tide problem

Jim needed to use the water in the bay to mix with the clean sand in order to pump the sand underneath a navigation channel, across the island, and through floating line to the Geotube feed ports.  Jim needed a flexible solution. Since he was pumping downhill under a 15 foot channel, he couldn't risk shutting down with sand in the line. He used one of his Crisafulli dredges to act as a mobile sand pump to adapt to the wind and tide level fluctuations in the bay. The dredge would be flexible enough that his operator could adjust the articulating cutterhead height, angle and distance to the feed, thus keeping the sand-water mix at an constant rate. This also allowed frequent start-stop operation to flush the line and switch Geotube feed ports, thus filling the Geotubes evenly.

sand spreader

Jim used a hopper with a belt to deliver the sand to a sand spreader.  The sand spreader distributed the sand evenly to match the 8 foot wide dredge cutterhead.  The cutterhead mixed the sand and water allowing for an optimal pump mixture.

dredge sand pump

Using the dredge as a sand pump Jim was able to pump the sandy mixture up to ½ a mile directly into each of the geotube ports spaced 20’ apart.   “(This project) needed a lot of flexibility which the dredge allowed for” Stated Jim.

Read Jim Dugan’s SWMER blog of his progress in the Mordecai Matters Winter 2010 newsletter

Watch video of the shoreline with the installed geotubes at Mordecai Island Geotubes in Action on YouTube.

If you would like to email Jim Dugan, send your email inquiry to jimdugan@comcast.net.

Watch SRS Crisafulli videos.

Topics: Dredges, crisafulli, dredge, dredging, marina dredging, srs crisafulli, dredging abrasive materials, lagoon dredges, dredging system, dredging and pumps

Proactive Dredging: A Little Now or a Lot Later

Posted by Elizabeth Kaiser on Wed, Oct 19, 2011 @ 08:10 AM

By Isaiah Helm, Applications Engineer, SRS Crisafulli

 

If public works departments had a list of fun things to do, dredging sediment out of holding ponds would not be on it.  It’s like cleaning the shower in your bathroom.  Whether you make it a frequent quick job or an occasional laborious task, time and effort must be set aside to maintain a fixture that is as critical as it is uninteresting.  This is the scenario that played out for Georgia’s Cobb County-Marietta Water Authority (CCMWA) during the summer and fall of 2010, as reported in Public Works Magazine

CCMWA had two water treatment plants and a 25 million gallon reservoir in need of upgrade to meet the EPA’s Stage 2 Disinfectant and Disinfection Byproduct Rule of 2006.  During the upgrade, one plant would be running, one shut down.  The reservoir had to be at full capacity to do this.  Unfortunately, it hadn’t been dredged since 1978 and was half full of sludge.  

 proactive dredging resized 600The reservoir was restored to its original 14-foot depth
within six months.  (Photo Credit:  Public Works Magazine)

Timing of all the different upgrade stages coupled with the EPA deadline meant the reservoir had to be cleaned out in six months.  (The dredging had originally been scheduled to take place 2013-2014.) 

In other words, the CCMWA had to make up over 30 years of maintenance in 6 months (that would be one nasty shower!).  The result: increased scale, decreased competition, and ultimately an increased cost.  The amount of dewatering equipment doubled.  Four mobile belt presses and four recessed chamber presses were used.  Fifty trucks made four 45-mile round trips per day.  Bidding on the project was limited to the few large contractors who were even capable of completing the project.  There were five bidders and all five of them listed the same two companies as their subcontractors.  Total cost to dredge the reservoir and perform maintenance on the banks and sluice gates totaled just over $4 million.

The World Dredging Mining & Construction Journal [1] contains a version of the article authored by Steve Gibbs.  It goes on to discuss some observations from the project:

One of the lessons learned by CCMWA is the need for regular dredging of the reservoir.  One benefit of regular dredging is economics – greater capacity in the reservoir reduces the amount of pumping necessary to bring water from the Chattahoochee, thus saving electrical costs.  Also, doing a smaller dredging project every five years or so will eliminate the need to do a massive project such as the one just completed.

A deeper, cleaner reservoir will allow suspended solids to settle out better, which will enhance treatment efficiency.  The reservoir will also have ample capacity while the treatment plants are in their construction phase.

“This (the reservoir dredging project) will decrease the potential for water quality problems or process issues at our treatment plants,” said Ginn (CCMWA process engineer). “It’s a very good proactive preventive maintenance step.”

There you have it.  Proactive dredging of sludge-collecting ponds really does make life easier in the end.  It also increases the options:

  • Put out a request for bids on that smaller dredging project every five years

  • Contract with a dredging company to clean out the pond every five years

  • Rent dredging and dewatering equipment directly and eliminate the middleman

  • Purchase an automated or remote dredging and dewatering system and have it permanently installed for complete self-sufficiency

At least it’s something to think about while you’re cleaning your shower tonight.

 

[1] World Dredging Mining & Construction Journal, “Proper Planning for a Perfect Project” (Volume 46, Nos. 11/12, Page 16)

 

Do you have a proactive dredging project in mind?  Fill out our dredge application form.

Need some advice?  Request a free consultation.

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Topics: Dredges, crisafulli, dredge, dredging, srs crisafulli, dredging abrasive materials, lagoon dredges, dredging system, dredging and pumps, dredging equipment rentals, rotomite sd110, lagoon, rotomite 6000c, Hydraulic dredging, rotomite 6000

How Dredging Equipment Rentals Provide Multiple Advantages

Posted by Elizabeth Kaiser on Thu, Aug 11, 2011 @ 13:08 PM

By Dave Stoltenberg, Dredge Rental Specialist with SRS Crisafulli

For many industrial projects, rental equipment is the way to go.  Especially for many dredging applications, which in most cases are only required periodically, with many years separating the jobs, rental equipment delivers a number of advantages.  Offering increased flexibility to respond to changing project requirements while avoiding capital investment, rental dredging equipment offers additional benefits such as:

  • Reduced maintenance costs
  • Faster ability to respond to emergencies
  • Better allocation of scarce project dollars
  • Access to dredging expertise, consultation, and training
  • No need for long term amortization across multiple projects

Rented dredging equipment can be used to augment a wide range of projects which contractors typically are asked to perform.  In addition to contractors, facility owners are surprised with how easy dredging is to learn, and can take advantage of short term equipment rentals.  Project applications for which rented dredging equipment is a perfect match include:

 
FLUMP dredge rental
  • Marinas
  • Golf Courses
  • Retirement Communities
  • Many industrial facilities such as paper, chemical, oil, and gas
  • Mining
  • Municipal water and wastewater

SRS Crisafulli maintains a rental fleet of dredging equipment to meet a wide variety of the most demanding dredging applications.  Our FLUMP and Rotomite dredges are state-of-the-art designs for maximum solids production, priced at a high value, cost effective rental rate. 

Contact us today for a dredging project consultation.

Learn more about SRS Crisafulli Dredge Rentals.

Request a Dredge Application form.

Please have Dave contact me about dredge rentals.

Topics: crisafulli, dredging, srs crisafulli, dredging equipment rentals

For $50,000, who wants to be a SRS Crisafulli Millionaire?

Posted by Elizabeth Kaiser on Thu, Jul 14, 2011 @ 13:07 PM

SRS Crisafulli's factory location is intriguing.  SRS Crisafulli is a dredge and pump manufacturer with a factory in land-locked Eastern Montana.  "Glendive, Montana is a unique and very rural community" says SRS Crisafulli President/CFO, Laura M. Fleming. "Glendive is about as far off the beaten track as can be found in modern America. We had two visitors from Israel this week, and sent them home with special stories about Eastern Montana."SRS Crisafulli Factory Employees

"Good People Surrounded by Badlands" is a phrase promoted by the Glendive Chamber of Commerce.  "It was even a $50,000 question on Who Wants to be a Millionaire" adds Ms. Fleming.

"When I present at public speaking events, I use the phrase:  'The River is our Teacher.'  The Yellowstone River and the unique terrain in Eastern Montana created the Company - and vice versa - the people who homesteaded in this area developed unique irrigation methods and technology.  The landscape contributes to the DNA of SRS Crisafulli" says Ms. Fleming.

Photojounalist Lynn Donaldson has visited the Glendive and the SRS Crisafulli factory on several occasions.  "You may visit Lynn's Montana blog at www.placesbetweenspaces.com where you will get a taste of real Montana", says SRS Crisafulli Sales Manager Maureen Lundman.

Yellowstone River at Glendive

The 28 year SRS Crisafulli veteran employee, Ms. Lundman, says "Glendive, our 'City by the Yellowstone', offers unrivalled scenery.  The mighty Yellowstone River bisects the town.  We're always watching the river."

Makoshika State Park

"Glendive is bordered by the rugged and majestic Makoshika State Park. Makoshika (Ma-ko'-shi-ka) is a variant of a Lakota phrase meaning land of bad spirits or badlands."

"Glendive is a warm & welcoming community, and a great place to live--with an excellent school system, a 2-year college, state-of-the-art medical facilities, fantastic hunting, fishing and recreation, as well as a good share of the fine arts available locally."

"SRS Crisafulli employees count themselves as fortunate to live under Montana's Big Sky!" comments Ms. Lundman.  

For additional background about Glendive, please visit:  www.glendivechamber.com

For additional information about Makoshika State Park, please visit:  www.makoshika.org

For a taste of real Montana, please visit Photojournalist Lynn Donaldson's blog:  www.placesbetweenspaces.com

Topics: Dredges, crisafulli, dredge, dredging, marina dredging, srs crisafulli, lagoon dredges, International Exports, Hydraulic dredging

SRS Crisafulli Dredges Featured Dealer: Titan Machinery

Posted by Elizabeth Kaiser on Mon, Jun 13, 2011 @ 08:06 AM

 

titan machinery logo

SRS Crisafulli has teamed up with Titan Machinery to offer local product support, maintenance, repair and comprehensive customer service to their customers across the country.


“Our priority is to help our dealers grow their business, and the best way we can do that is to offer them the broadest selection of equipment and the best customer service available,” says Richard C Memhard, Chairman of SRS Crisafulli.

Titan Machinery owns and operates one of the largest networks of full service agricultural and construction equipment stores in the nation, with 87 dealerships nationwide.


The agricultural machinery and attachment equipment 
Titan sells and services runs the gamut from large-scale farming machinery to home and garden equipment. They offer a wide selection of heavy construction and light industry machinery for both commercial and residential construction, road and highway construction and mining applications.


On the construction side of the business, they service a wide range of customers from owner-operators to large fleet customers to the municipal and government markets.

 “Our goal at Titan Machinery is to provide world-class solutions, including pumps and dredges, to our customers.  Crisafulli is a great company with an excellent product.  Leveraging the Crisafulli product line with the Titan Machinery full-service dealership network provides excellent value to our customers.” said, Mike Hall Marketing Manager for Titan Machinery.


To learn more about SRS Crisafullis Product Line, download our DVD here.









Topics: Dredges, srs crisafulli, titan machinery

Dredge Dealer Dairy Specialists Wins Business Ethics Award

Posted by Elizabeth Kaiser on Fri, May 20, 2011 @ 09:05 AM

Dredge DealerDairy Specialists, an SRS Crisafulli agricultural dredge dealer for more than two years, was awarded with the Colorado-based CEBA Bill Daniels Business Award in March for conducting every aspect of its business with the highest of ethical standards.

Companies who receive the CEBA award are nominated by customers, vendors and organizations in the community at large.

When asked why Dairy Specialists was selected for this award, Owner Randy Sorensen had the following response:

“I think the way we choose to do business really resonates with people.

Dairy Specialists’ mission statement serves as the framework for how our company operates.

Mission Statement:

Dairy Specialists will be the Rocky Mountain Region’s Premier Provider of Dairy Construction, Supplies and Service by providing:

  • The Best Designs in the Marketplace
  • The Best Construction Quality & Time to Completion
  • The Best Service & Products Available
  • The Best Internal Systems in the Industry
  • The Best People in The Business
  • The Best Value for Our Customers…Our Partners

 

We will be Outstanding Citizens of the Community that Makes Our Business Possible.

Creating a culture driven by the mission statement is a function of ethical, principled leadership at Dairy Specialists. The Leadership Team models the way for all our employees by framing every activity and decision it makes around the questions, “Is it the right thing to do?” and, “Does it drive us towards completion of our mission?” It’s simple, but it seems that, when framed in these terms, every issue, be it with vendors, customers, employees or the community at large yields consistently fair, quality outcomes. Our employees have quickly embraced this approach to doing business and feel empowered to make decisions and act accordingly knowing they will be supported.”

Dairy Specialists, one of three honorees, was selected from a group of 27 finalists, including 13 companies, seven non-profits and seven individuals representing a wide range of industries and community organizations from hospitals and youth agencies to law firms and financial institutions.

Dairy Specialists is one of the largest and most innovative dairy service and supply dealerships in the country. Supplying commercial dairy farms with innovative parlor designs, new construction, remodels and state-of-the-art dairy equipment and dairy waste management technology.

Dairy Specialists consult with their Dairy Customers for SRS Crisafulli’s Trailer Pumps and Remote controlled FLUMP Lagoon Dredges.

As with the agricultural industry , 2008, 2009 and early 2010 were 30 of of the worst months in the last thirty years for the entire dairy industry and specifically for dairy farmers in Colorado. Declining milk prices, increased feed and energy costs, coupled with the failure of one of the largest local dairy industry lenders, New Frontier Bank, led to the perfect storm for Colorado dairy farmers.

The opening of a new Laprino Foods Plant in Greeley will ultimately lead to the need for additional milk generation in the state, which will open up new opportunities for Dairy Specialists to participate in the design and construction of new dairy parlors as well as in the expansion of existing facilities. Ongoing innovations and involvement in bringing green energy and efficient waste management technologies to agriculture and the community as a whole, represent realistic opportunities for growth. The prospects for a good year in 2011 are looking up for the Colorado Dairy Industry.



To learn more about SRS Crisafulli dredge and pump solutions for the agricultural industry click here

 

To speak with Randy at Dairy Specialists email him at: Randy@dairyspecialists.com or visit www.dairyspecialists.com

 

If you have a dredging need request a dredge application form here.

Topics: Dredges, crisafulli, dredge, srs crisafulli, flump, lagoon, agriculture

Hydraulic Dredging: A cost effective solution for most dredging tasks

Posted by Dick Memhard on Fri, May 06, 2011 @ 06:05 AM

hydraulic dredging with crisafullis sd110The vast majority of dredging jobs require removal of solids to depths of 30 feet or less. Several features enable hydraulic dredges to be the solution of choice for these applications.

First, what are hydraulic dredges and how do they compare with alternative mechanical dredge types?

Hydraulic dredges create slurries, combinations of solids and water, pump the slurries to the surface of lagoons, ponds, lakes, waterways, and canals, and then pump the slurries through floating and land based pipe to disposal sites. The hydraulic dredging process can be continuous, as contrasted to intermittent in the case of so-called clamshell dredges.

Basic components of hydraulic dredges include a cutterhead, pump, floatation system or platform, engine or motor, control system, and the discharge system. Cutterheads dig up settled solids in the waterway to be dredged and create slurries.  A powerful centrifugal pump mounted directly behind the cutterhead draws the slurry into a discharge piping system, pushes the slurry to the surface, and then to the discharge site, often thousands of feet away from the dredging site. The engine, typically diesel, or electric motor, by means of hydraulic motors and high-pressure hose, transfers the engine’s power to the cutterhead and pump, and in the case of self-propelled dredges, such as SRS Crisafulli’s Rotomite-6000, to the dredge’s propulsion system. Hydraulic dredges integrate the foregoing components into a balanced, highly productive and efficient system.

Hydraulic dredges are made in several configurations, all of which except for cutter/suction and spud dredges, and dredges that require a support vessel, are made by SRS Crisafulli:

  • Horizontal auger hydraulic dredges
  • Suction dredges that have no auger
  • Free standing, self-propelled, steerable dredges with one or more onboard operators
  • Remote controlled dredges typically controlled by a cable system within a well-defined area
  • Dredges with varying degrees of automation
  • Dredges that can operate safely in highly caustic applications
  • Dredges that operate efficiently without a support vessel, or dredges that require a support vessel
  • Cutter/suction dredges
  • Dredges that are positioned with spuds (long, powerful spikes driven into the bottom of the waterway) and use hydraulic rams to apply forward force to the cutterhead
  • Hydraulic dredges are defined also by the depths to which they can dredge, the volume of water and/or solid material they move, the height to which they can discharge the slurry, the power of the auger (or cutterhead), the hardness and abrasiveness of the slurry, the size of solids the dredge pump can pass, dredging speed, width of dredging cut, the cutting power (torque) of the auger, and the cost of the dredge.

The foregoing features all contribute to and determine the productivity of the dredge and the owner’s Return On Investment (ROI) – i.e., how much work the dredge can do in relation to the initial cost of the dredge and the ongoing operating, repair and maintenance expenses of the dredge.

Other types of dredges and solids removal systems are classified as mechanical and include:

  • Clamshell dredges that typically must be operated with a crane
  • Huge, ocean going vessels that can dredge huge volumes at great depths
  • Drag lines that haul a large shovel through the area to be dredged

Each of the foregoing three dredge types provide advantages and disadvantages, including:

  • With the possible exception of draglines, these systems are far more expensive to buy and operate than horizontal hydraulic dredges. For example, horizontal auger hydraulic dredges vary in cost from approximately $150,000 to $700,000. SRS Crisafulli’s most expensive horizontal auger hydraulic dredge can be purchased new in 2011 for approximately $350,000 plus the cost of accessories, spare parts, and options. A high capacity cutter/suction dredge can cost upwards of $1.5 million. An ocean going dredge can cost several million dollars.
  • For the vast majority of applications these three alternative mechanical systems are “over kill”.
  • Clamshell/crane dredging systems together with the large barges the systems are operated on can dredge to greater depths, and dispose of the dredged materials many miles away at dumpsites approved by the EPA. But these systems are bulky, noisy, and more costly to buy and operate.

Selecting the best dredge solution for any application requires careful analysis by experienced, well-trained people in collaboration with the customer’s staff. Frequently, such an analysis requires the efforts of engineers with the skills and experience to sort out the many variables.

What would you like to do now?

  1. Request a dredge application form?
  2. Download the SRS Crisafulli product information DVD?
  3. Speak to one of our qualified technicians about your specific dredging requirements?

Topics: Dredges, crisafulli, dredge, srs crisafulli, Hydraulic dredging

Dredging Abrasive Materials? Learn about SRS Crisafulli’s New Dredge

Posted by Elizabeth Kaiser on Fri, Apr 29, 2011 @ 06:04 AM

dredging abrasive materials rotomite 6000cThe Rotomite-6000-C, SRS Crisafulli’s newest self-propelled dredge, broadens the Rotomite-6000’s capabilities to include removal of highly abrasive materials. The Rotomite-6000-C also increases the customer’s return on investment (ROI) by cutting sludge management costs, increasing user productivity, and enhancing the unit’s maneuverability for the removal of toxic and non-toxic solids.

The new design offers capabilities that will benefit industrial companies, including; chemical companies, food processing plants, domestic and international construction and contracting companies, oil, mining and refining companies, petrochemical plants and refiners, and coal fired utility companies. Municipalities, County, Regional and Federal agencies, as well as lake associations, and landfill operators, will be able to use the Rotomite-6000-C in many applications. In addition, the Rotomite-6000-C helps companies comply with domestic and foreign mandates by ensuring manufacturing by-products are contained safely in order to prevent contamination of drinking water.

This versatile, self-propelled design is a horizontal auger, hydraulic dredge that can work in odd-shaped areas where a cable dredge unit cannot go. It can remove, pump and discharge dredged solids in water/solids slurries through a floating discharge pipe to disposal sites up to 5,000 feet away, or more when a booster pump is used.

The Rotomite-6000-C is 40 feet long by 9.5 feet wide, and is easily transported by truck.  Its 255-horse power motor and new propulsion system provide increased production and propulsion thrust. It will dredge most soft or abrasive materials, including alum and lime sludges, bentonite, biosolids, bottom ash, clay, coal fines, fly ash, gypsum, mine tailings and slimes, mill scale, mud, pigmentation sediments, industrial and municipal wastes, pulp and paper residuals, peat, oil API sludge, sediments silt and sand.


Capabilities include:

  • Dredging depth of 23 feet standard (up to 30 feet optional)
  • Up to 235 cubic yards of sludge solids produced hourly
  • A discharge volume of up to 3,400 gallons per minute @ 180’ TDH (water)
  • A dredging speed of up to 25 feet per minute
  • A dredging cut up to 8.5 feet wide
  • A cutterhead torque of 11,500 inch/lbs.
  • A draft of 30 inches

The self-propulsion feature provides increased maneuverability, more forward and reverse speeds and a 72-horse power hydraulic motor that powers a propeller system capable of 2,500 pounds of force. SRS Crisafulli’s exclusive Cobra cutterhead, which provides 11,000 inch-pounds of digging torque and up to 235 cubic yards of sludge solids per hour, increases productivity. The hydraulic ladder results in enhanced downward force by providing 30,000 pounds of down pressure to dig into the settled solids materials more aggressively thereby increasing cutting capacity. An improved cab design provides operator safety and convenience features, including air conditioning and heating.


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Topics: dredge, dredging, srs crisafulli, dredging abrasive materials, rotomite 6000c