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Kaustubh Katdare
Kaustubh Katdare • May 18, 2008

Polluted Sea - What to do?

I'll expect some response from the marine & chemical engineers here.

I spend last weekend on the beach at Dapoli (Konkan, India). Its a beautiful place to visit. I was hurt to see that such a beautiful place has a polluted sea. I could see all different colored chemicals floating on the water πŸ˜” .

I was wondering if we'll ever be able to make the sea pollution free. Any ideas, folks?
Mayur Pathak
Mayur Pathak • May 19, 2008
Yes. We can definitely help. As they say, charity begins at home. Lets first all of us start behaving properly whenever we go to the places of natural beauty. To start with lets keep our surroundings clean. Only then we can take our good habits to the nature.

Second, we need to learn to say no to chemicals. Do you know that the drain from our bath rooms goes to the seas ultimately? Its our duty to make less use of harmful chemicals every day. Also spread a playful word around against use of products like Phenol, Acids etc.
just2rock • May 20, 2008
See..Biggie its really sad what you see..i can understand..but see untill and unless we all bends towards safer life and Cleanliness (from a leywman -to Corporates) this wont change...So lets hope that we wILL soon make a way out of it...Just keep you Hope LIVE LONG...believe me U!
Kaustubh Katdare
Kaustubh Katdare • May 20, 2008
I guess I should clarify the purpose of this thread.

Are there any technical solutions to the problem that's being discussed?
Indeed.. prevention is better than cure. That should probably a principle for engineers. But anyway, we should still think of a way to fix the existing pollution problem.

Regarding chemicals.. maybe we should approach it like how oil spills are cleaned up. One can use "sorbents" to absorb the chemicals from the water like a sponge. Another method is to use biological agents to break down the chemicals into harmless compounds.

Of course, thats as much as I can contribute regarding to technical stuff πŸ˜› I'd have to research these methods more thoroughly to see their feasibility in cleaning chemicals (or sewage) from the sea.
Mayur Pathak
Mayur Pathak • May 21, 2008
Gee... Ash was quicker than me to post about absorbents. πŸ˜€

Anyway, I forgot what they are called, but there are these compounds when added to dirty water they behave like potassium permanganate. They coagulate the dirt, dust, fats and oils from the water and take them to the bottom. This is a normal practice for clearer waters (say lakes) but don't know if its the same being done for Sea as well.
Oh, thats interesting! So then we could just scoop them up from the bottom? Maybe a underwater collector robot can clean them.

I just stumbled upon a shelf in the uni library, displaying books on Water treatments and engineering. Gonna be a long read for sure.
Mayur Pathak
Mayur Pathak • May 21, 2008
No you need not scoop them. The material becomes biodegradable. It either gets eroded by the waves or gets amalgamated with the rocky or silty bottoms. πŸ˜€

Waste water engineering was fun, when I did my civil engineering.
Hey, what about if we equip a hive of small autonomous boats equipped with "sorbents"? They can have chemical detectors and share information from each other wirelessly, combined with aerial and satellite images. This could possibly enchance the cleaning efficiency. The "boats" don't have to be fabricated with expensive designs.. they just need to float and propell across the water. In fact, we can add solar panels so they can remain in sea longer (and extend mission range). A single "command" boat, operated by humans can be used to launch these small boats and observe their operation.

Some info of sorbents here:
Sorbents | Comprehensive Procurement Guidelines (CPG) | Wastes | US EPA

I skimmed through a waste water book. Ya know the pipes that go into the sea from the beach? It consist of processed waste water, but other wastes still get mixed into it. They are then diffused far away into the sea. Unfortunately.. a "plume" of waste can occur just below the water level.. so we might not actually see the extent of how polluted the sea really is. Anywayz, the book got into some detailed diffusion analysis.. I proceeded to put it back in the shelf πŸ˜›

That got me wondering. For landlocked countries.. are rivers their only waste water outlet?
Alright, here's the idea in a diagram. The "pink" boat represents the Command Ship, while the yellow ones are the robots. White dashed lines are the communication links between the Command and robots, while the red lines represent inter-robot ad hoc communications. Forgive me for my choice of colours.. I was rushing it a bit πŸ˜›


Software: Inkscape. Used the freehand function to draw the outlines of the chemical dispersion, and simply used Fill. Skewed the water textures to give it that isometric view.. though the angle is not exactly 60[sup]o[/sup]!

Water texture: Water Textures - 3d models for 3d studio max Poser Bryce Lightwave 3d engines and textures
Mayur Pathak
Mayur Pathak • May 26, 2008
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?
Kaustubh Katdare
Kaustubh Katdare • May 26, 2008
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?
Mayur Pathak
Mayur Pathak • May 26, 2008
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.
Kaustubh Katdare
Kaustubh Katdare • May 26, 2008
Oh, I"m not πŸ˜€ as I said, the idea is good...rather fantastic! πŸ˜€ I was thinking about alternate ways to eliminate the root cause!
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 πŸ˜› 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 πŸ˜€ 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.
Mayur Pathak
Mayur Pathak • May 27, 2008
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. πŸ˜€

Interesting, eh?
gohm • May 29, 2008
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.
Ashraf HZ
Ashraf HZ • Jun 4, 2008
Oops, didnt have time to put a diagram last weekend πŸ˜”

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?
Mayur Pathak
Mayur Pathak • Jun 9, 2008
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 • Jun 17, 2008
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?.

Daaaamn.. its been nearly a year since we discussed this. Thats what happens when you mix procrastination with studies and other projects πŸ˜‰

I'd like to continue with it, now that I'm armed with more experience with robotic and wireless modules.

I still owe you guys a new diagram. Need to rethink all the old ideas and study a bit more about sorbents.

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