pollutant concentration is important for method selection. But water  amount is high. 

 So cost will be high. 

thank you for your answer Prof. Towe.

I just want to know, which are the best technologies to treat this wastewater; since 3 million gallons do not seem to be cost-effective (even for the traditional processes of coagulation/precipitation of water treatment)

 Thank you very much for your answer Prof. Özturk

Evidently high volume of pollutant involves a high operation cost, but are the traditional methods efficient to treat 3 million gallons? 

To treat this amount of pollutant, I think it will be more effective to use a combination of traditional processes ( i.e., hybrid processes)

Hybrid processes will be  more effective. 

Perhaps the more important question is...how can the acute and chronic toxicities of the specific metal species, as well as the extent of impacts in the river systems be minimized.  I believe that volume of water impacts in the various river systems is already so large (has anyone made volume estimate to date and a model of continued volumetric impacts) that only a high efficiency filter type or diversion system could be constructed and even then this may not be feasible.  Mitigation of sediment and shoreline impacts may be the only feasible way to address longer term impacts.  There is a great knowledge base in the acid mine drainage area of research and field work. I would hope and also believe that EPA and other agencies, such as USGS would be fully engaged in this effort.

Considering the environmental issues and water treatment with low cost is easy to understant the necessity of combined tecnology. As a sugestion first precipitation /clarification processes followed by ultrafiltration membrane. Important to add the cost of toxic sludge discharge.

Considering the environmental issues and water treatment with low cost is easy to understant the necessity of combined tecnology. As a sugestion first precipitation /clarification processes followed by ultrafiltration membrane. Important to add the cost of toxic sludge discharge.

Considering the environmental issues and water treatment  cost is easy to understant the necessity of combined tecnology. As a sugestion first precipitation /clarification processes followed by ultrafiltration membrane. Important to add the cost of toxic sludge discharge.

Considering the environmental issues and water treatment  cost is easy to understant the necessity of combined tecnology. As a sugestion first precipitation /clarification processes followed by ultrafiltration membrane. Important to add the cost of toxic sludge discharge.

Has the source of pollutants been plugged yet?

Add high iron clay suspension which can scavenge metals and settle down at the bottom.

Thank you Proff Atula for your comment

Adding clay suspension is a good Idea, but it will also create a big amount of Mud in the river.

what do you suggest to recover this mud from the river?

http://www2.epa.gov/goldkingmine

the best way for removing metal waste water is using adsorbent such as active carbon,alumina .clay and filing wood. 

Humic Acids are probably the most innocuous and effective absorbents for metal remediation in both sediments and water. Metals absorbed onto the humic acid containing materials will typically pass leaching tests.

Yes, sorption process is one of the effective options for metal removal.

But, for this volume (3 million gallons) It would be better to combine adsorption with some other processes; such as coagulation/precipitation, etc.

Dear Professor Abd El-Aziz A. Said

Thank you for your answer

I think sugarcane bagasse is an interesting bio-material to evaluate, since cellulose has been demonstrated to be a good sorbent for metal removal

I think sugarcane bagasse modified with propionic acid is the good way for removing metal waste water.

In the mean time polluted water is flowing down to the ocean. A similar episode happened in Aznalcollar (Spain). I think the main question is how to avoid this kind of accidents to happen again. The obvious response is to treat mine waters while contained...

Hello Demey !

I think that you must use  from seaweed and fishes . I read a paper about remove  Arsenic from a river ! with a  type of fish that their gills treat water !

I hope that you be successful . Sorry  I do not have any time that find this paper for you.

Humic Acids and Humic materials would be the most economical and least harmful to the environment. They have been shown to tie up most metals and even pass the leachate test. Humic materials occur naturally in soils and are what give some swamps and rivers a brown color. They are harmless to fish and wildlife.

Thank you for your interesting answer Dear Andrew Eckles

Humic acids occurs naturally in soils, but is the effectiveness comparable with the traditional sorbents?

I think, in this field (bio-sorbents), the biopolymers such as chitosan, and alginate would also be interesting to evaluate.

Important results for metal removal have been reported in the literature using chitosan. In my opinion, among the targets of EPA, would be to design a pilot plant with hybrid processes (using traditional low-cost processes).

I agree that biopolymers can be potentially very useful and are worth pursuing. I would be very interested in comparing various options on some leading metal contaminants such as Hg, As, Cr, Cu & Pb. Several reasons that I lean towards humates are: 1. Strong bonding to most metal ions (I have personally tested them with quite a few metals) (in pH levels below 10), 2. very stable & resists degradation, 3. relatively innocuous, 4. many potential natural sources

Dear Dr. Hary,

It happened many times, that a tailings dam broke and metal-containing residues from ore processing were released to nearby rivers. The problem is not, that the water needs to be treated, it is the metal-contaminated solids which were released. The good news is, that the residues commonly are not very much water soluble. So it is not that, what the colleagues above are concerned about.

The remaining problem is the accumulation of metals on the river bed, which needs to be removed owing to mercury compounds and others, which are changing their chemical characteristics over the years and will be released in small portions slowly to the water. I guess that most of the rivers in the former mining areas of the US have a considerable high metal contamination.

From time to time a remediation of the river bed sediments will be done such as recently with the Fox River in the US or the Nura River in Kazakhstan.

Dear Dr. Hary,

Thank you, that you like my answer.

Regards

Ruediger

Guys you don't need to add anything to the water such as clay or what ever. THE WATER IS NOT THE PROBLEM!!! - Metal-containing particulate matter will settle from alone. - Otherwise you have to dispose a lot more contaminated material when the real remediation occurs. Most of the suggestions above are far away from any practical application. Sorry to say that.

Dear,

Reed bed System/Wet land system which is maintenance free for metal removal from wastewater and feasible for large scale. you can see the installation in USA & India.