Guide

Chemical manufacturing waste and hazardous waste

Chemical manufacturing and reaction vessel waste

Many of the chemical manufacturing processes your business uses take place in dedicated reaction vessels that will need washing. The washing process can generate significant levels of hazardous waste. Also, the flexibility that stirred-tank reactions offer your business can mean that raw materials are often not used efficiently.

Larger chemical manufacturing processes often use vessels for mixing, reaction and product separation. These vessels can have a blind spot on their mixing blades and drainage design that can be improved. When your business replaces a vessel, you should choose a design that:

  • avoids wastage when it is emptied
  • reduces the need for cleaning
  • enables - where possible - cleaning in place to occur with automated changing and emptying

If your business is able to use low-inventory fast reactors, these can offer your business a number of savings, including:

  • reduced need for cleaning
  • less product waste at the end of the reaction run
  • less void space/dead legs where product could hide
  • cost savings, as the vessel is usually designed for one specific process

Vessel design and washing advice

There are a number of steps your business can take to improve its overall vessel design and washing including:

  • reducing the amount of washing that takes place and the amount of wash liquor that is used, as this reduces effluent
  • improving staff awareness of the environmental and financial implications of excessive washing and effluent production
  • logging vessel activity to minimise the need for washing between product batches
  • changing your production processes to reduce the need for vessel washing
  • recovering used wash liquor and switching to alternative, less hazardous washing agents
  • full vessel drain-down
  • using high-pressure washing systems, as they are more efficient and reduce the volume of wash liquor needed
  • automating the washing process, as computer-controlled systems can be more accurate and improve washing performance
  • installing closed-loop systems that minimise emissions, improve solvent use and protect operators from contact with wash liquors - closed-loop systems enable wash liquors to be reused rather than disposed of after each wash