Dear Dorna, I am guessing ...
Published by AquaVerde SCHWAGER, CEO at AquaVerde
Dear Dorna,
I am guessing your Dairy farm Wastewater have a high content of COD, more them 1,000 mg/l?
If so, you may chose AD as pre-treatment like an ABR (biogas!!!) and after that an aerobic secondary treatment system like CW or a pond system. See https://www.sswm.info/water-nutrient-cycle/wastewater-treatment/hardwares/semi-centralised-wastewater-treatments/anaerobic-baffled-reactor-%28abr%29
Good luck
Detlef