Dredging World News Blog

Mine Restores Basin Capacity with Hydraulic Dredge

Posted by Isaiah Helm on Tue, Nov 18, 2014 @ 12:11 PM


SRS Crisafulli introduces the Rotomite model 6000-CD Dredge

SRS Crisafulli designed and built the self-propelled, steerable, diesel powered all-purpose dredge for both abrasive and soft slurries with a cast alloy pump, and 8” discharge, in the fall of 2013.  The dredge was tested at Fisher Sand and Gravel’s pond on Circle Highway northwest of the Company’s Glendive, Montana manufacturing plant, just before winter set in.

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Photos:  R6CD dredge testing at Fisher Sand and Gravel, Glendive MT, 2013

2014 Job Site

During the winter, the SRS Crisafulli Dredge Sales and Rental Department worked with a copper mine in the American Southwest on a Dredge Rental contract. The mine needed to restore their basin capacity without stopping mine processes, which is the perfect application for hydraulic dredging.

Dredge Application:

Problem: The customer has a plastic-lined tailings dam that collects outflow from various processing facilities. The mixture is generally acidic, with lye added to balance ph levels. A floating pump transfers water and material from this small catch basin into a very large permanent tailings impoundment. The limited ability of the floating pump to pull in slurry led to a build-up of solids, which reduced the pond’s holding capacity.

The customer wanted to restore this capacity to original levels without stopping any mine processes or damaging the liner.

Solution: The new SRS Crisafulli Rotomite model 6000CD was selected for its ability to handle abrasive tailings materials. The Rotomite 6000CD also proved to be well suited for pumping through 500 ft. of 8 in floating discharge pipe, 1500 ft. of 10 inch fused pipe, and over an 80 ft. berm at 1300-1500 gpm. No booster pump was required, reducing cost and complexity of the system. The cutterhead was outfitted with a liner protection cage, preventing its horizontal auger from damaging the liner as it pushed slurry into the pump. This cage restricted the auger from digging into settled solids, so SRS Crisafulli’s unique cutterhead articulation became indispensible as the primary method of breaking up material.

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The hydraulic thruster on the back of the Rotomite 6000CD was also a critical component. Both the perimeter and floor of the basin are irregularly shaped, and it is surrounded by a fence, making cable positioning difficult and cumbersome. The thruster’s 180 degree range of motion and hydraulically variable depth allowed quick and easy positioning of the dredge during operation and docking.

The project began with an estimated 76,000 cubic yards of material to be removed.  A satisfactory quantity of tailings was removed to restore the impoundment’s capacity.

Thanks to the SRS Crisafulli dredge rental program, the copper mine’s project was completed in less than six months.

 

The inaugural season of the R6CD was a great success.

Please call the offices to schedule a rental for 2015, or inquire about an equipment purchase.

 

 

Topics: dredging equipment rentals, Hydraulic dredging, Tailings Dam, Rotomite 6000CD

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

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.

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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