Polluted Sea - What to do?

[mayurpathak]

Interesting, very interesting! I just have one doubt. The boats will have to cover the entire area in order to have the sorbent effective. Which means they will have to be in the sea for a very long duration.

A suggestion, instead of using robot controlled boats, you could do away with fishing nets and/or the bulbs that are used to keep them floating. They not only spread across a larger area but are also cheap. What say?

[The_Big_K]

Well, the idea is good but I think it is not practical. Well, as MayurPathak says, the boats will have to cover the entire sea (which makes it impractical).

I'd say let's accept the damage done till now. Let's think of what can we do to prevent the sea from polluting further. How can we stop the pollutants from entering the sea?

[mayurpathak]

That is right biggie. But don't write off the project yet. I think what ash says makes sense, at least for a smaller catchment areas and land locked water bodies. Because I believe the movement of the water will be largely responsible for the effectiveness of the project. More turbulent water, less will be the coagulation.

Ash, expecting your view.

[The_Big_K]

Oh, I"m not as I said, the idea is good...rather fantastic! I was thinking about alternate ways to eliminate the root cause!

[ash]

Ah thanks for pointing out the problems guys!

Hmm.. lets say we have a "hive" of the robots, which might be a few dozen or so, and since they are mobile, maybe a large area wont be a problem.

Great idea about the nets. If we can equip it with the robots, you've got a larger area covered too (ie mobile nets). It depends on the design of the robot.. which I haven't thought deeply into yet For example, how do the chemicals get removed from the sorbents into a storage tank on board, what is the capacity of this tank, or will it travel back and forth into the command ship to dump it's load, etc. To reduce cost, we can just use waterproof plywood. If P.V cells are too expensive, a windmill could work too.

If we do want to know how much area it can cover within a certain time, you'll need to know the parameters such as how fast the sorbent can work, the speed of the robot, water turbulence, wind, etc. Multiply that with the size of the hive too.

Now that you bring up the net idea, we can also do this:
We can deploy a large ring with sorbents that will encircle the area thats effected, just like water buoys and markers. Perhaps this is similar to what is done for oil spills. Then, we will slowly decrease the size of the enclosed area so that the chemicals will pushed into the middle, sorta like how hose clamps work At least the chemicals wont spread out too much during water turbulence. We could have the robots within the enclosed area doing their thing, or have water pumps filtering the water (the clean water outlet is external to the enclosed area).

I'll try to draw the diagram to give a better idea, this weekend. Theres one thing to take note; we are assuming that this is a "clean up" operation, yea? Length of mission wont factor in much, since we will only do it once a while and leave it to the "preventive" measures to protect the seas.

Regarding that, there are many "root" causes. Chemicals can come from household, factories, ships, ports, etc. We can probably control the chemicals coming from the land by monitoring pipes as well as rivers and tributaries. However, it’ll be much more difficult to stop chemicals from entering the groundwater.

Chemicals from ships are quite hard to control too since there are so many (and quite spread out in the sea). Perhaps newer ships have some sort of chemical waste regulations (kinda like the double hull rule for tankers) but they are just a fraction to the number of ships existing already, with a significant proportion being a decade or two in age.

[mayurpathak]

Very interesting ideas Ash. Great Work!
I'm running short of time today. But I'll surely come back on your ideas. I'll just tell you an interesting story.

Our hometown (biggie and me) is a city located at the center of India with tropical climate conditions. We have about 3 lakes in the city. One of them, near my residence is a big lake (approximately 1 square kilometer) situated in the center of the city. Since it is in the midst of all the hustle bustle, it is subject to getting polluted by enormous waste. Every year, the municipal corporation does the maintenance and has a unique way of cleaning it . They add sufficient quantity of absorbing chemicals to the lake for 2 weeks at the start of March month, causing coagulation. In April and May, the temperatures in the city soars over 45 degree celcius. So as the lake begins to dry, they manually excavate the subsided silt and dirt in order to clean it. This also ensures that the bottom is scored and opened for fresh water springs. And for the rest of the year it is left for people to pollute again.

Interesting, eh?

[gohm]

They do make chemicals that cause hydrocarbons (i.e. petroluem) to congeal and salidify. they then float on the surface where a skimmer boat can collect it. It still needs to be removed as a solid hard lump of petroleum is still a pollutant. It was used in cleaning up the Exxon Valdez spill. Dawn dish soap is another widely used substance for cleaning as well as the absorbant booms. Active filtering is also possible however it is not efficient and also removes benefitial material. As mentioned, prevention is the best along with time and the actions of nature for pollution. Nature is amazing in its resilentcy.

I always envisioned a non toxic chemical that would react between water and petroleum based material to form a gel. This way it would encase any petroleum products with a gel like capsule or egg so the pollutant could be not only contained but salvaged for use. It could also be pumped into oil tankers so it would react as soon as a leak appeared.

[ash]

Oops, didnt have time to put a diagram last weekend

By the way, we are all assuming that the pollutant can float right? How do we make chemicals (note, not specifically oil)that are dissolved with the water float? Fight chemicals with more chemicals?

[mayurpathak]

Still waiting for your diagram Ash. By the way, if you are adding any sorbent in the water, it will also take care of the dissolved pollutant, albeit it has to be particulate matter. If there are compounds who have changed the property of water, then it has to be treated. For that we need flowing water. I'm not sure how they treat the still water by some other method.

[Alexander]

Well i think i have an idea for this one, all the water from the sea has to rush ashore and since the chemicals we are talking about are basically semi dissolved, they will remain at a moderately higher level.( assuming that sorbents are ot used).
threefore, the water can be purified as and when it comes ashore...
this cycle may take sometime before the water in the vicinity is comparitively cleaner,leter more methods can be adopted.
The idea of the robotic boats was great, but i believe that it has its limitations, especially in water bodies near comercial ports. They will be a hindrance, possibly time-burglars.
All ive thought of so far is how to purify carbon impurities form the water...
some others can also be done in the process, but thats where ill need ur suggestions.
Tell me what u think of this idea?.