Dear Similade, the cheapest ...

Dear Similade,

the cheapest way are the long Time used coagulant flocculant iron sulfate (by- product of iron industry) or aluminum sulfate. In resident cases I have been using extremely low doses of poly-aluminum, which makes a bigger flock. 

Now there are new technologies on the market, which propose to give you a green label like http://www.organicabiotech.com/  this particularly important for all companies which work in the sector of bottling drinks, as they are major water consumers and interested to assure a good relationship with the government,in order to keep access to water in time of climate change and scarcity.

sludge should be dehydrated and burned in a modern waste incinerator, as nobody knows what happens to polymers once exposed to nature.

with kind regards

Thomas