In general, to process 1 liter of milk  on an average 2.5-3.0 litres of waste-water gets generated.  Generally this waste-water contains large quantities of fat, casein, lactose, and inorganic salts, besides detergents, sanitizers etc. used for washing; oils and grease which are used in instruments/machines. All these components contribute largely towards their high biological oxygen demand (BOD), chemical oxygen demand (COD).

There are many ways to control/reduce BOD n COD levels. With the help of Effective and Good management practices one can reduce these spillage from milk processing units, drippings, washing of cans, tankers bottles, utensil, and equipment’s and floors etc., automatic cleaning system – CIP (cleaning in place) system and Modern effluent systems are the integral part in in dairy industry, these must work efficiently.  Installing of filters at all drainage is also one cost effective way. focus on sources of waste in dairy industry from all the entry to exit points.... Per say from cheese plant; whey is going to drainage...so use it for by-products ( whey powders)... extract excess of ghee from ghee residues... many such management practices are there...  

You can go for biological processes such as anoxic treatment and physical-chemical processes such as chemical dosing (flash mixing, flocculation and settling) for this followed by 3-stage Nano-filtration process to control the parameters and meet the regulatory criteria.

You can use fenton process for Dairy effluent treatment or use of premeditation technique also applicable

I use a connection to be inserted into the exhaust pipe sysmemt, that allows me togather a homogeneous part of the discharge in a bucket

Thanks everyone for your response.

For the control of COD of dairy industry waste water you can use the aerobic methods like trickling filters. it is also low cost method which follow aerobic degradation of organic matter.