Dredging World News Blog

Natchez Wastewater Treatment Facility Finds Success with New System

Posted by Elizabeth Kaiser on Fri, May 04, 2012 @ 08:05 AM

By Elizabeth Kaiser, SRS Crisafulli Marketing Manager

A popular magazine at the SRS Crisafulli offices is Treatment Plant Operator (TPO), which serves municipal water system operators.

The November 2011 issue of TPO featured the Natchez, Mississippi Wastewater Treatment Facility in their Top Performer - Biosolids section, with an article titled "Sun Dried Success". 

"Natchez is the site of a new “greenhouse” solar biosolids drying system" states TPO.

The American Council of Engineering Companies recently awarded WGK, Inc., the general civil/engineering and surveying firm for this project, their Grand Conceptor's Award for the design of the upgrades to the plant.  Congratulations to WGK!

Natchez has two, 3-acre holding ponds.  Prior to their system upgrade, the disposal process for the sludge from these holding ponds was expensive and time consuming.  Natchez WWTF hauled their biosolids - with solids content of 10% - and disposed of the material using liquid injection at a nearby site. 

Today, the wastewater treatment plant produces a biosolid with at least 75% solids that meets class A standards.  A SRS Crisafulli FLUMP dredge helps the plant accomplish this new standard successfully.

 Natchez FLUMP dredge

 Photo Credit:  TPO magazine, November 2011

Installing a FLUMP dredge eliminated transportation and equipment rentals costs, and reduced environmental risks. The total project impact has reduced operating expenses by at least $200,000/per annum.

Michael Stewart, Natchez Wastewater Treatment Plant Manager, told SRS Crisafulli their goal was "not to make money but to save money."  Michael said they "save money every time they start the FLUMP dredge."

The Natchez Wastewater Treatment system went online a little over a year ago.  Today, their Crisafulli FLUMP dredge is operating 8 hours a day, while in production, and is going strong.  The Crisafulli FLUMP dredge pumps the dredged sludge from the ponds to a 65,000 gallon tank.  The sludge is then pumped to a belt press conveyor system.   The FLUMP dredge fills this 65,000 gallon tank twice a day.

The Natchez Wastewater Treatment Facility intends to resell the sun dried product to farmers. The wastewater treatment facility will not only save money with their new system, but will also make money.

Do watch the November 2011 TPO video of the Natchez system, narrated by Michael Stewart, Plant Manager.  He does an excellent job of explaining the art of this 5 million galls/day rated wastewater treatment facility, serving a population of 30,000.

 

 

Read the TPO "Sun Dried Success" article.

Read Natches Democrat article "Water Works awarded for dealing with your waste".

Watch a Crisafulli FLUMP video.

Read Crisafulli FLUMP case histories and testimonials.

 

Topics: Dredges, crisafulli, dredge, dredging, lagoon dredges, dredging system, dredging and pumps, flump, lagoon, TPO, Treatment Plant Operator, Municipal dredging, biosolids

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.

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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.

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

Dredging Short Courses

Posted by Elizabeth Kaiser on Wed, Nov 23, 2011 @ 08:11 AM

By Eric Lillberg, SRS Crisafulli Senior Applications Engineer

When I first started as an applications engineer for SRS Crisafulli, I searched for information on the subject of dredging. I was surprised to find there was very little non-commercial content available. I have since found a pair of short courses, offered annually by Texas A&M, which I recommend highly to any professional interested in dredging. The Center for Dredging Studies at Texas A&M has amassed a teaching staff of notable individuals from the dredging world.

 Center for Dredging Studies

Dredging Engineering Short Course

Sixty four participants attended the 4 ½ day Dredging Engineering Short Course held January 11-15, 2010 at Texas A&M University in College Station, Texas.  The short course was sponsored by the Center for Dredging Studies in the Coastal and Ocean Engineering Division of the Zachry Department of Civil Engineering.  Participants received a certificate of completion and 2.9 continuing education units. 

A wide range of dredging and dredged material placement topics were covered including: dredge pump and slurry pipe flow principles; sediment re-suspension; basic geotechnical engineering and dikes; cost estimating; basic dredge laws; cutter suction and hopper dredges and dredge automation; modeling dredged material placement; contaminated sediments; geotextile tubes; instrumentation, surveying and positioning; silent inspector program; confined disposal and capping; environmental regulations; testing manuals; EPA and port perspectives; wetland creation; enhanced settling of dredged material; beach nourishment; sand-water separation techniques; and beneficial uses of dredged material.

The next Dredging Engineering Short Course is scheduled for January 9-13, 2012 at Texas A&M University in College Station, Texas.  More information and an application may be obtained from
r-randall@tamu.edu or Center for Dredging Studies.

 

Cutter Suction Dredge Simulator Short Course

The upcoming Cutter Suction Dredge Simulator Short Course will demonstrate the fundamentalCutter Suction Dredge Simulators of hydraulic dredging using a cutter suction dredge. Topics will include cavitation, deposition of sediment in the pipeline, cutter power, pipeline length limitations, pump power limitations, different sediments (fine sand, medium sand, stiff clay, etc), channel currents, and swing winch limitations.

In the January 2011 course the simulators were programmed with a 24-inch (610 mm) spud carriage and fixed spud dredge (other size dredges can be simulated as well).  Three simulators interfaced actual controls for a cutter suction dredge to personal computers, and each participant spent approximately 30 minutes on a simulator for each of 7 exercises.

In February a second simulator short course was offered for dredging personnel from the J. F. Brennan Company, of LaCrosse, Wisconsin.  In June a third simulator short course was conducted for the Bureau of Reclamation, of Yuma, Arizona. For the June course, the simulators were programmed with a 12-inch cutter suction dredge with spud carriage, to match the new dredge purchased by the Bureau from Ellicott Dredge.

The next simulator short course is scheduled for January 16-18, 2012 at Texas A&M in College Station, Texas.  More information and applications are available at  Center for Dredging Studies.

Topics: Dredges, dredge, dredging, dredging system, dredging and pumps

Dredge Pumping Systems Improve with VFD Motor Controls

Posted by Elizabeth Kaiser on Wed, Nov 09, 2011 @ 08:11 AM

Submitted by Dave Stoltenberg, Dredge Rental Specialist, SRS Crisafulli

Pumps and Systems MagazinePumps and Systems recently published an article by Christopher Jaszczolt titled “VFDs Improve Motor and Pump Control”.   The article discussed current applications of variable frequency driven (VFD) motor controls as an excellent method to improve on mechanical control methods.  VFD control systems have gained market share and visibility in the past decade as an excellent motor control methodology with the added benefit of energy conservation.  By implementing VFD controls on dredge pumps, dredges become much more usable with the typical slower processing speeds of dewatering systems. 

Jaszczolt says:  ”Preferably, some of the pumps can be shut down when demand is low, and the system can be designed so that the water pressure can be maintained by a single pump during periods of low demand. Properly designed lead-lag systems will improve the efficiency, performance and longevity of the pumping system.

Jaszczolt also tells us:  “Like a PLC—advanced VFDs can be programmed, monitored and maintained with PC-based software. Unlike a PLC, this software is generally provided free by the VFD supplier. VFD programming and monitoring software is also easier to use than similar software for PLCs because the software is for a single application specific rather than general purpose.

VFDs have been used to control pumps for many years. However, advanced pump-specific VFDs now allow users to improve motor/pump control and protection without the need for inefficient mechanical devices or costly PLCs.

 

Christopher Jaszczolt is an application engineer with the Drives and Motion Division of Yaskawa America, Inc., in Waukegan, Ill. He has a BSEE from Northern Illinois University and five years’ experience applying variable frequency drives in industrial applications.

Read Christopher Jaszczolt’s complete article online at:  VFDs Improve Motor & Pump Control

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Topics: Dredges, crisafulli, dredge, dredging, 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)

 

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