Keeping the bulk milk tank clean

Using a tank cleaning system tailored to the bulk milk tank size, configuration and other available resources (water volume and quality) will minimise the need to climb inside the tank and scrub the surfaces by hand.

Automation of bulk milk tank cleaning can enable the tank to be cleaned immediately after emptying, reducing the risk of milk residues settling on the tank surfaces, and so limiting the opportunity for bacterial growth.

The benefits of selecting the right cleaning system include:

• • Lower costs: decide which system will cost the least to install and run.
  • Increased work efficiency: select the system which will require the least labour to run.
  • Maintain milk quality: select the system which cleans most effectively.

Different methods of cleaning the bulk milk tank require varying labour inputs and offer varying scope for automation.

Manual cleaning involves cleaning of the bulk milk tank using buckets and brushes. It is limited to small lidded tanks because good access to all internal surfaces is needed.

Advantages:

• • Inexpensive to establish
  • Effective results if done properly.

Disadvantages:

• • High labout cost (if done properly).
  • Danger due to lifting buckets of hot water and detergent into tank (protective clothing should be worn when manually washing bulk tanks).
  • At risk of people taking short cuts due to time needed to do the job correctly.
  • Areas of the bulk tank are easily missed, eg under bridge, agitators and corners.

Manual cleaning in place (CIP) involves the fitting of a spray ball or similar device at the top of a bulk milk tank.

The spray ball distributes cleaning solutions to all internal surfaces. Pump sizes, spray ball design and water volumes need to be matched to provide good cleaning.

Advantages:

• • Can be retro fitted to most bulk tanks.
  • Relatively inexpensive to install.
  • Safer.

Disadvantages:

• • Sparay balls can block, resulting in areas of the tank not being cleaned.

Limited contact time of detergents if the water is not recirculated.

Optionally, automatic cleaning in place (CIP) has distinct advantages, and some disadvantages.

Advantages:

• • Wash cycles can be tailored to suit size and configuration of tank and local resources.
  • Repeatable and consistent wash cycles.
  • Error and fault reporting.
  • Integrated with cooling systems.
  • Usually supplied with a dedicated hot water service.
  • Minimal handling of chemicals.
  • Required volumes of water and chemicals are reduced by recirculation.
  • Tank can be completely washed immediately after emptying.
  • Little labour input.
  • Safer.

Disadvantages:

• • Wash times can be excessive (outside milk processor requirements) if the water pressure is low.
  • Spray balls can block, resulting in areas of the tank not being cleaned.
  • Expensive.
  • Often only available as an integral part of the bulk tank.
  • No system is fully automatic; chemical drums and effectiveness of wash program need to be monitored.
  • Automated systems not working correctly and going unnoticed by people.
  • Power cuts may change cleaning cycle times.

Do your homework

• • When installing a system consider the costs involved and the labour input required
  • Beware: bulk milk tank cleaning requires the use of concentrated chemicals and/or large volumes of hot water. Health and safety issues arise from this practice. Many tanks are 'confined spaces' and entering them can cause death from asphyxiation. Always remove the silo door when you enter.
  • Never stand in a confined space where acid and alkaline cleaners mix, eg at the bottom of the bulk milk tank.