Remediating conventional-agriculture polluted water

Hi everybody

we are designing a 5-hectares (12 acres) farm in cool temperate climate, and water flowing from upstream conventional field of 3.5 hectares (9 acres) are reaching the property.
It's polluted, there is a brownish foam and we want to clean it before we release it in our property through swales or release it to the creek directly.

Can you advise on how to bioremediate this polluted water, so we can either use it or release to Nature ?

Thanks for your help.

To really do anything you need to know what the pollution is IF it is pollution, foam doesn't have to be pollution based Here is a link on how to tell the difference between man made and natural foam brown foam is most likely to be natural.

Actually we are pretty sure that it is fertilizer pollution, because we have talked to the farmer there.

We'd like to know what are the applicable strategies to efficiently clean this water.

More and more farmers are restoring (or deliberately not disturbing) riparian areas between their fields and bodies of water.

If it's only fertilizer, then willows, cattail, and wetland grasses/sedges/rushes will happily soak it up.

If it's a fertiliser problem he will be receiving  a huge fine in most countries. I wouldn't even think about cleaning the water but stopping the problem, any farmer putting enough onto the field that it is coming off in the water course will be seriously overdoing it or applying to close to water.  Also check your local laws here we are not allowed to do ANYTHING to permanent water courses or within 10 meters of the edge and we are certainly not allowed to block ditches/drains or streams with water plants, you don't want to make someone elses problem into your fine. If it is surface run off then willow/reed beds should sort it for you and are probably the best place to start searching. They are used for everything from industrial treatment to black and grey water treatments.

Thanks guys for your answers.

Do you have an example of design of a small wetland, that optimizes the length of the path of water, with willow trees and other plants ?

In our case, we have a rectangle of 18 m x 7 m to achieve this phytoremediation.

Thanks