Did you know, in India, 15 percent GDP comes from Chemical and Allied Industries? Now imagine the scale of pollution these industries can cause. Is it measurable? Yes, it is. Take a look at this table.
Pharmaceutical processes comprise of many number of stages, hence lots of waste, hence the E-factor is huge. Continuous processes and catalytic processes are very easy to control, hazards associated with them are less as compared to batch processes. Hence, petroleum refinery has less by-products (kg/kg of product). In this context, a continuous and a catalytic process means minimum waste.
Let me introduce you to a concept called as ‘waste hierarchy‘.
Waste hierarchy is a an upgraded version of the 3R concept. Relating it to the current topic, we can say that Pharmaceutical industries do not do the recycling part of the pyramid because they are worried about purity, fairly so.
One may ask, why do people still look out for greener methods for batch processing? It is because, certain products are only needed in batch quantities and hence need to be produced in a batch process. Also, some companies can only afford batch equipment.
I presented a seminar on ‘Greener methods for Batch Sulfonation’ during my post-graduation. You can take a look at it here: Seminar on Greener methods for Batch Sulfonation