Housekeeping Note: I think I am the last one on the planet to start using Twitter. I remember last year boasting to Michael at WaterWired that I would never use Twitter. Like the sage he is, he predicted in a blog post that I would eventually. He was right. Visit My Page.
Its been awhile since I have posted some groovy graphs. I stumbled across this graph last night.I have seen different graphs like this, but not quite put together like this. I like it.
This is a continuation from my previous blog post about one of the largest environmental cleanup projects ever attempted in the United States.
So, what exactly happens with the sediment?
The barges holding the sediment will be moved to a new waterfront barge unloading facility along the Champion Canal.
An excavator puts the sediment into a trommel which separates finer sediments from the debris, gravel and rocks. The remaining material is pumped into one of two hydrocyclones, where grit and sand is removed.
The slurry that's left is piped to an 80-foot diameter gravity thickener tank where polymer is added to clump larger particles together. The thickened slurry is then pumped from the bottom of the tank to one of 12 filter presses housed inside the dewatering building.
Filter plates inside the presses basically squeeze water from the slurry to form filter cake. Water removed during processing is filtered and discharged into the Champlain Canal.
The filter cake is loaded on to an 81-car train for disposal to a toxic waste facility in Andrews, Texas. GE has purchased an astonishing 450 new rail cars for this project. When this project is at full throttle and processing 500 cubic yards of sediment every day, the train will be leaving every 2.5 days.
The entire project will remove a staggering 1.8 million cubic yards of sediment.
Last Friday with lots of fanfare a single scoop of PCB enriched sediment was dredged from the bottom of the Hudson River. By some estimates 1.3 million pounds of PCBs, or polychlorinated biphenyls, entered into the upper Hudson from two General Electric factories for three decades before they were banned, in 1977.
While the media concentrated on the history and significance of this event, I don't there was sufficient shock and awe to the mechanics of the dredging operation. This six year dredging operation is unique in its size and scope.
First, a breakdown of the dredging hardware:
1. Environmental Clamshell Bucket. The excavators are equipped with environmental clamshell buckets that seal and minimize overspill. The Environmental Clamshell Bucket differs from traditional dredging buckets by allowing water to pass through its top moveable vents as it submerges, thereby contributing to the reduced turbidity.
2. Flexifloat barges. This is the swiss army knife of all barges. Modular deck barges attach to one another and can be configured in many ways. This is a simple, quick and economical method of moving all types of construction material on water. They even have been used as floating bridges.
3. Dredge. A dredge consists of an excavator on one of the Flexifloat barges. Up to 12 dredges will operate in and around the dredging area at any time.
4. Hopper barges. Seventeen barges will be used to transport the sediment dredged from the river to the treatment facility. Each barge can hold 100 tons of sediment. The barges were transported all the way from Louisiana.
5. Tugboats. Eighteen new tugboats will be used to push the barges to the project areas and to the Processing, Treatment and Transportation Facility.
6. Miscellaneous Survey, Crew, Support Boats. They will use these various vessels for getting to the dredging sites, testing and monitoring, and oversight. Survey crews check monitoring equipment this past Friday in the picture below.
Next blog post, I will try to breakdown what happens to the contaminated soil.
I have seen different graphs like this, but not quite put together like this. I like it.
An excavator puts the sediment into a trommel which separates finer sediments from the debris, gravel and rocks. The remaining material is pumped into one of two hydrocyclones, where grit and sand is removed.
The slurry that's left is piped to an 80-foot diameter gravity thickener tank where polymer is added to clump larger particles together. The thickened slurry is then pumped from the bottom of the tank to one of 12 filter presses housed inside the dewatering building.
The filter cake is loaded on to an 81-car train for disposal to a toxic waste facility in Andrews, Texas. GE has purchased an astonishing 450 new rail cars for this project. When this project is at full throttle and processing 500 cubic yards of sediment every day, the train will be leaving every 2.5 days.
2. Flexifloat barges. This is the swiss army knife of all barges. Modular deck barges attach to one another and can be configured in many ways. This is a simple, quick and economical method of moving all types of construction material on water. They even have been used as floating bridges.
3. Dredge. A dredge consists of an excavator on one of the Flexifloat barges. Up to 12 dredges will operate in and around the dredging area at any time.
4. Hopper barges. Seventeen barges will be used to transport the sediment dredged from the river to the treatment facility. Each barge can hold 100 tons of sediment. The barges were transported all the way from Louisiana.
5. Tugboats. Eighteen new tugboats will be used to push the barges to the project areas and to the Processing, Treatment and Transportation Facility.
6. Miscellaneous Survey, Crew, Support Boats. They will use these various vessels for getting to the dredging sites, testing and monitoring, and oversight. Survey crews check monitoring equipment this past Friday in the picture below.
Next blog post, I will try to breakdown what happens to the contaminated soil.
