Effluent Treatment in Chemical Industry

I would like to know if there is any process to reduce the amount of Chemical Oxygen demand in Effluent wastewater in Chemical Industry. Please Reply
Our Company Produces Sodium Salt and it generates 22,000 ltr of wastewater every 10 hours, in which there is more than 35,000 COD present and I am finding a way to reduce the amount below 5000 anyhow if possible. Please help!!!