The easy method for remove heavy metal is phytoremediation. You try to find ethno plant in your contry. Aqatic plant in your country is suitable. But it only remove from water to plant. Some plant canchange form of heavy metal from toxic to nontoxic. This method is easy than other method.

A: not put them there in the 1st place. :-)

Q: how large of a body of water? What are the physical/chemical properties of the said water? What are the constraints on the applicable treatments ? (ie: metal ions tend to precipitate at high pH)? etc. Can you be more specific?

there are lot of methods for removing metals from water, including adsorption using activated carbon, nanomaterials, various composites,chemical precipitation, phytoremediation etc.

You must more precisely describe: to which metals and under what conditions are to be conducted these processes.

Though time consuming, Constructed wetlands could be probably the best environment friendly technique (phytoremediation) to remediate large water bodies contaminated with heavy metals. You can find several research articles and success stories in google. This is also the oldest remediation techniques among phytoremediation.

You can try to adsorb the heavy metals on muddy or clayey soil. Than you have only to deposite the contaminated soil as waste. About ten years ago this method was processed on the water from a little lake, which was contaminated with heavy metals from a grinding mill.

I agrre with Rachna that wetland are a very good technique, but it depends on the wetland type. see: Retention of resources (metals, metalloids and rare earth elements) by autochthonously/allochthonously dominated wetlands: A review

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1) Phytoremediation of heavy metals-Concepts and applications

2) Plant-bacteria partnerships for the remediation of hydrocarbon contaminated soils "

Phytoremediation is an environmental remediation technique that takes advantage of plant physiology and metabolism. It is possible to remove huge amount of heavy metals using aquatic plants (e.g., water hyacinth).

Introduction of aquatic weeds like Eicchornia helps in removing heavy metals form natural water bodies, but care is to be taken that Eicchornias population remains at manageable level/number as it is aquatic weed

I agree with Jintapat , Rachna and Abebe comments about wetland and using aquatic plants suitable for lakes. But it is difficult to apply the adsorption technique for lakes.

If the sodium concentration in the water stream is low, Zeolites would be a good candidate. see list of my publication as reference. I would be more than happy to help in this regard too.

I do agree with the suggestion given by the different scholars. It is nice to know what type of natural water body. running or stagnant? what is the depth of the sediment and depth of the water column.

The use of different adsorbent is obvious but not sure in a natural big waters.

Still the application of phytoremediation is vital and more practical in the natural systems. However it is always advisable to look for the indigenous plants capable of removing metals.

A very low portion of the total metals concentration will be in solution, which makes plant uptake not feasible or timely in most situations. The solid phase ("quantity") only releases a tiny bit to the solution ("intensity") in response to solution concentrations. Keep in mind that plants can only uptake ions from solution, not from a solid, so the dissolution-desorption is a necessary first step. You probably do not want to hear this, but usually the most feasible and effective method is dredging to actually remove the majority of the metal (which is in the solid phase). You will find that most environmental consulting/engineering firms will employ this as their most cost effective method for bodies of water.

Thanks to all for the prompt response. Let i inform you that i test heavy metals in one of the pond which is mainly dominated by Eichhornia. Results showed that water and fish of the body contains beyond recommended levels of heavy metals. If phytoremediation is useful then why that water body and fish contain beyond permissible limits of heavy metals?

Have any body applied these above mentioned techniques practically?

An important question to ask is where the contamination is coming from. You can clean the water perhaps, but if the source area remains cleaning the water will only briefly help. Also, what type of metals are we talking about? Some more readily adhere to sediment/soil and others are easily transported in the water column. You'd need to take into consideration: type of metal, type of soil/sediment, amount of dissolved metals in the water column, and information regarding the surrounding ecosystem. That will help you determine the first step or whether or not phytoremediation is an option. Keep in mind sensitive environmental areas (i.e. rookeries, threatened or endangered species habitat) and laws of the area. If phytoremediation isn't a viable option and you want to go the dredging route there are multiple permits that need to filed (in the U.S. at least).

Hope this helps :)

I am working on cu, ni, fe, co, mn, cr, zn, cd and some water bodies are surrounded by local populations while some are restricted areas.

Where is the contamination coming from? Is it from runoff from contaminated surface soils? Is it in the sediment due to groundwater contamination? While plants will uptake some contaminants the source of the contamination needs to be determined. If the source is ongoing the contamination will be ongoing and the plants will help (maybe) but that won't provide you with a solution.

I must agree with all the above comments. Phragmites for phytoremediation perhaps

Mehjabeen,

Jessica has addressed some important points regarding water cleanup. I would also recommend that you find out the nature and concentration of the heavy metals and pH of the water. You may be fortunate enough if they are all cationic in nature (lead, mercury, cadmium, etc.) at the pH you're dealing with. The problem is far more difficult to resolve if you are dealing with anionic contaminants at the pH of your water (chromates, selenates, arsenates, etc.).

Should you find that the contaminants are cationic, then you may be able to try clay or natural zeolites to sorb the contaminants onto the clay (or zeolite) mineral.

Best wishes,

Fernando Cadena

Jessica Mauricio makes some very good points: it’s crucial to identify the key sources of the metal assemblages, and the types of metal present, before effective longer-term solutions can be proposed and assessed (and I guess it’s a large freshwater body, and not marine or tidal?).

In addition, I’ve made the following points below.

1. It is important to recognise that, in many systems, dominant pollutant sources – and pathways - can switch between, or within, rainfall events or seasons, in relation to changing intensities and spatial patterns of storm rainfall, water inflow routes and inflow rates.

2. The ‘dynamics’ of metal transport are therefore also important, especially during storm events. Concentrations of many pollutants can sometimes increase, or dilute, by 2-3 orders of magnitude during and after storms. This means that any sampling programmes normally have to be planned to capture these key temporal changes and process dynamics in order to gain a reasonable understanding of the contaminant transport processes in the transporting or receiving waters, as well as metal flux rates (i.e. not simply based on one-off ‘snapshot’ sampling).

3. These effects can be exacerbated if metals become 'associated' with suspended sediment in the inflowing streams. Many contaminants have a great affinity for, and bind on to, fine sediment, partly because of the massive specific surface area available per gram with such small particles which can be exploited.

4. It should be recognised, too, that these fine sediment concentrations can also increase 100-1000 times during high-flow events (e.g. see our paper in Science of the Total Environment 2006, vol. 360, pp. 109– 126, on UK storm-event turbidity and suspended sediment dynamics in urban rivers, which I’ll attach): such changes are likely to substantially increase affinity and metal association potential in the water body and its influent streams.

5. See also the detailed work over the last 15 years on such problems by the Atlanta, Georgia, USA group led by Art Horowitz, e.g.: Arthur J. Horowitz, Kent A. Elrick and James J. Smith. 2001. ‘Estimating suspended sediment and trace element fluxes in large river basins: methodological considerations as applied to the NASQAN programme.’ Hydrol. Processes. 15, 1107–1132). DOI: 10.1002/hyp.206.

6. The Reference lists in any of Art’s papers will provide a useful resource for many of the issues discussed above.

I hope these points are useful to you in understanding the problems and forming solutions. Good luck!

[email protected]

Lime as a precipitating agent !

There is a series of technologies to choose from:

1. Electrodialysis

2. Nanofiltration

3. Membrane distillation

The selection depends on the heavy-metal load, cost and energy requirement as well as the desired water quality.

Thermal processes like MED and MSF or Reverse Osmosis seem to be too costly for your application.

To answer the question, there is a need to provide the following answers (data). Provide, maximum concentration of the heavy metal, particular of the heavy metal, treatment technique to be used, location of the treatment plant, quantity of the water.

It is of importance to know the probable ppm level of the heavy metals. You can use large plastic sheets which is embedded with polymers bearing metal ion adsorbing sites. Since the surface ares is large it is possible to remove high concentrations of metal ions.

A biological method could be to transplant enough number of fresh water mussels & place them in the body of the water body.Phytoplankton has an ability to bio accumulate these metals with ingestion of the cells & their detritus. You can increase the variety of phytoplankton species by importing from other water bodies.The idea is to involve greater varieties of these primary producers & these will be consumed by the mussels.Corresponding increase in the bivalves also will have to be carried out. Check out the concentration of the metals in question in the body of the mussels. It is important that these mussels after a time need to be fished out & removed from the water system- otherwise their consequent death will annul all the above remediation.

It is very important to know the types of trace metals, their concentration and the final concentration required. Also we should take into consideration the available capabilities to recommend any treatment method to be used. We should also take into consideration the disposal of waste from any selected treatment.

You can employ the vermifiltration technology which uses earthworms as biofilters, the earthworms removes organic wastes as well as heavy metals

The question itself answers it, if you are already through the analysis part of it you should be able to tell what the heavy metals I am up to are? Going by the basics one could easily precipitate this chemical if one alters the pH but collection becomes a big issue. Phytoremediation is one of cost effective method Eichhornia crassipes is known to intake lead and Arsenic similarly Ipomea aquatica is known to intake Arsenic, Salix viminalis for Cadmium. On the same lines the molluscs could be utilized to absorb the pesticides like DDT and BHC which they do by biomagnifications through food chain. Similarly there are other plants which could be used to stabilize and absorb these contaminants on the banks. But all said than done the old saying holds good “prevention is better than cure” So stop the pollutants entering in ecosystems and onto your life.

i agree with Holger Schweyher absolutely, Membrane and distillation methods are good approach for treatment of heavy metals from large amounts. adsorption process, biological methods and ion exchange are good but these approach cab be used for smaller scales of water and not used for large natural bodies of water.

I do not think that M. M. Manyuchi comment is applicable for this case.

Adsorption method is more effective method for the minimization of waste by using low cost materials. It efficiency can be enhance by the modification of surface of adsorbent.

of course adsorption is a good Technic and it better with modification or treating, but it is not a good Candide for this case.

Tertiary treatment process, biological unit processes. Chemical redox method etc.

Just ad lime to the waterbody

Cost effective and easy method to remove heavy metals from large natural water bodies. Since the heavy metals to be removed from large natural water bodies chemical method and membrane filtration is ruled out. First find out the heavy metals and their ppm values. There are carefully designed polymers like polyesters, polyamides which has very high adsorption capacity towards many heavy metal ions.

Please refer:

Novel Polymeric Adsorbents Bearing Amide, Pyridyl,

Azomethine and Thiourea Binding Sites for the

Removal of Cu(II) and Pb(II) Ions from Aqueous Solution

Selvaraj Dinesh Kirupha a , Arukkani Murugesan a , Thangaraj Vidhyadevi a , Palanithamy

Baskaralingam a , Subramanian Sivanesan a & Lingam Ravikumar b

Separation Science and Technology, 48: 254–262, 2013.

Synthesis, Characterization, and Heavy Metal Ion

Adsorption Studies of Polyamides, Polythioamides

Having Pendent Chlorobenzylidine Rings

L. Ravikumar,1 S. S. Kalaivani,1 A. Murugesan,1 T. Vidhyadevi,1 G. Karthik,1

S. Dinesh Kirupha,2 S. Sivanesan2

Journal of Applied Polymer Science, Vol. 122, 1634–1642 (2011)

By careful design, you can adjust the Tg of such polymers so that it can be caste in to very thin sheets. These sheets when placed at different heights in the water body, heavy metal ions will get adsorbed on to the surface of the sheet. They work at neutral pH. After desired time the sheets are removed and the adsorbed metal ions are striped out from the polymer surface with dil.HCl.

This method is most cost effective since they can reused for sevsral times and there is no need for regeneration.

Bioremediation with white-rot fungi

Growing algae in the body of water is a cheap way to remove heavy metals.

Hello,

You could use an activated carbon to remove the heavy metals, if the concentration is weak. But, the most important thing is to determine the type, quantity of heavy metal before to use an experiemtal set up.

I agree with Mr. Giddings , growing algae is a cheap and sustainable options. But, the effect on toxicity should be checked

It depends on which metals. Maybe chemical adsorption with clays or other functional materials is a good option to solve it.

In a larg watere body is difficult and expensive to apply the most of the wastewater treatment processes. Ηeavy metals will partial precipitate naturally with time (and pH ) and will exist in the sediment. Some algae can help the process with low cost. Important: Is aprocess easy applicable.

Hi Mehjabeen

You can removed heavy metals from large natural water bodies with chemical Percipitation method and then filtration . If the concentration of them are low you can use adsorption methods

As you plan to do lab studies you can try algea to remove heavy metals depending upon the concentration in wator bodies. another possible way could be planting perrinial trees with capacity to addsorp metals (phytoremidiation) at the boundary

Thanks to all

You should read Duffus 2002 about the term "heavy metals". According to IUPAC the term shoud not be used any more:

Duffus, J. H. (2002): "Heavy Metals" – A meaningless term?. – Pure Appl. Chem., 74 (5): 793-807, 3 Fig., 4 Tab.; Oxford.

http://bit.ly/Duffus2002

An economically effective method will be constructed wetlands. Application with constructed wetland is very flexible, meaning that you can use locally available species of plants within your locality for effective and efficient remediation.

Indeed constructed wetland is an economically method for efficient remediation of polluted water and soil.

This must be complex strategy:

1. Contaminated large water bodies should be isolated and additional contamination should be avoided.

2. Apply all methods of remediation that are available.

3. Adsorptions of metals from water using adsorbents are useful only if the treated water will be used for other application (e.g. water supply or irrigation).

Adsorption or Ion exchange for huge volumes of water is best suited. Technologies other hi fi methods may not be suited economically and effectively..

Metals can be removed. It can be recovered and reused also.

There is not a single method that can be opted for all metals from all sources.

For example, if there is a single metal in high concentration then we have to go for e.winning, preceded by some routine treatments.

If many metals are available in that water sample then we have to plan and best suited treatment strategy.

If many source is from industrial sources then the scenario is entirely different. If it from natural rivers then its easier... natural tanks meant for agri purposes etc to be studied. Any way if there is no other inlets from industries or domestic sources reaching rives or your natural water body then go for simple Ion Exchange.

Good Question.

In my opinion the cost effective and easy method to remove heavy metals from large natural water bodies is by the aquatic phytoremediation. In this technology use purely aquatic plants such as the floating water hyacinth (Eichhornia crassipes); or submersion of the rhizosphere of terrestrial plants in order to remove metal pollutants (rhizofiltration) [1-2].

As you are planning experiments in the greenhouse/laboratory. First of all you have to know which metal is present in toxic level in your selected water samples. Secondly to select the aquatic or terrestrial hyperaccumulator plants for the specific metal [3]. In the green house, prepare the seedling with hydroponic or pot method depend upon the plant species. Store the metal contaminated water, preferably in the plastic or glass tanks with an aeration facility like fish aquarium. Insert aquatic plant directly, but for the terrestrial plants use wooden plankton with holes, which accommodate pots (bottom with holes for roots to come out) with selected hyperaccumulator plants growing in metal free soil. At the different interval analyze the level of metal in the water and also in the plant parts. In other experiments you may use the plant roots infected with mycorrhizae, which enhance metal uptake or chelating agent for the metal bioavailability for the plants.

In 2002 a study was done by the Department of Pharmacology at Bangabandhu Sheikh Mujib Medical University in Bangladesh that used Water Hyacinth to remove arsenic from water [4].This study proved that water could be completely purified of arsenic in a few hours and that the plant then could be used as fire wood and many other practical purposes. Since water hyacinth is invasive it is inexpensive to grow and extremely practical. At a contaminated wastewater site in Ashtabula, Ohio, 4-week-old sunflowers were able to remove more than 95% of uranium in 24 h [5].

1. Dushenkov, V., Nanda Kumar, P.B.A., Motto, H. and Raskin, I., 1995. Rhizofiltration: The use of plants to remove heavy metals from aqueous streams. Environ. Sci. Technol. 29:1239-1245.

2. Brooks RR, Robinson BH (1998). Aquatic phytoremediation by accumulator plants. R.R. Brooks ed. Plants that Hyperaccumulate Heavy Metals: their Role in Archaeology, Microbiology, Mineral Exploration, Phytomining and Phytoremediation. CAB International. Wallingford. pp 203-226.

3. Chaudhry, T.M., W.J. Hayes, A.J. Khan, C.S. Khoo. 1998. Phytoremediation focusing on accumulator plants that remediate metal. Aust. J. Ecotoxicol. 4:37–51.

4. Misbahuddin, M., and A. Fariduddin. "Water Hyacinth Removes Arsenic from Arsenic-Contaminated Drinking Water." Archives of Environmental Health 57.6 (2002): 516-8. SCOPUS. Web. 26 September 2011.

5. Dushenkov, S., Vasudev, D., Kapulnik, Y., Gleba, D., Fleisher, D., Ting, K.C., Ensley, B., 1997. Removal of uranium from water using terrestrial plants. Environ. Sci. Technol. 31: 3468-3474.

the cost of remediation and the effectiveness of the method is vital here. The level of pollution needs to be determined and the metals that has polluted the water need to be known, i think the best option will be using the aquatic plant(s) that will effectively remove the metal pollutant. In my opinion, phytoremediation is the best option.

If you are looking for some practical assistance it may be worth getting in touch with Varicon Aqua solutions: http://www.variconaqua.com/contactus.php