Turbidity, colloidal issues etc is virtually indefinable. It is simply too broad of a term. Like tannins, turbidity is a description of a problem rather than an actual contaminant. Pilot testing is key unless you are aware of common causes/solutions that are common in your area.
The obvious solutions can be as simple as gravity filtration (settling) with the use of a contact tank, to as complex and alum injection, contact time, oxidation, and UF.
We have seen chocolate colored water turn crystal clear with a cheap 5 micron melt blown filter (they did not last long, but they were cheap), to problems that take a multistage approach. We work with a lot of companies to make them simple pilot test filters that can allow them to design an appropriate filter specific to their water quality problem.