Grey wastewater is usually household wastewater without the fraction from toilets. There are obviously similar fractions from pharmaceutical industries.

Pharmaceutical industries are generally not very willing to reuse water. Safety is very highly prioritised and pharmaceutical industries rarely have a significant economic gain from water reuse.

If reuse is applied it is likely there the reuse water doesn't get in contact with the products. Such as biological treatment and/or membrane before use in cooling towers. I have been in contact with industries interested in advanced oxidation or ozonation, but it turned out the concern about the degradation products of the chemical treatment was to much to handle once the technical solutions should be approved by authorities.

The so called grey water ( floor wash,rain water,spills,hand wash etc) is a small fraction and can be used for toilet flushing,gardening and floor wash  after a simple treatment of settling and filtration.Better not use it as process water.These solutions can not be generalised  and each industry can optimise the water  use by specific means.In general it doesn't make economic sense for pharmaceutical industry. 

 in my opinion, as  Dr Henrik  said Pharmaceutical industries are generally not very willing to reuse water. 

Thanks for the answers Dr.Henrik Rasmus Andersen, Dr.Prakash Pimparkar and Dr.Randa M. Osman. I believe what Dr.Henrik Rasmus Andersen said was abolutely right. Makes perfect sense. 

The pharmaceutical industries comprise generally recalcitrants emerging contaminants (even it is grey water). Only Advance oxidation processes such as ozonation, photocatalysis, sonolysis or plasma processes are sufficient to remove these recalcitrants from pharmaceutical waste water. Then only we can reuse these water in processing purpose. Otherwise, after biological or biomembrane treatment we can reuse in flushing, gardening etc. as Dr. Prakash mentioned.

Thank you Raj Kamal Singh for your valuable answer. But I doubt that recalcitrants can be considered as grey water (partly). Please let me know why you consider recalcitrants to be grey water.