First: the question is about ...

First: the question is about TDS and not TSS, so settling will not resolve much to reduce TDS.

Second: sand filters don't treat, only concentrate the solids in the backwash water. They can be used for final polishing with the backwash to the biological treatment step (see further on).

Wastewater from the vegetable industry can contain a high amount of solids from washing, these can be removed by settling (after a fine screen). Lamellae settlers are very effective and can be equipped with a surface scraper for floating solids, which also exist in the wash water! More TSS can be removed with a DAF system, with chemical dosing (PAC, polymer).

Then the wastewater can contain quite some dissolved organic matter, which can be treated with aeration, but is only effective in the presence of dedicated bacteria (activated sludge as MLSS), final sludge settling and return. Excess sludge treated separately by dewatering, drying, composting etc.