Re-Use Detergent Wash
Acid detergent solutions designed for use in cold water are well suited for re-use. Capturing and storing the solutions for re-use requires minor changes to the pipework and an extra sealed wash barrel.
Capturing and storing the alkali solution is more problematic as the solution needs to be hot when used (at least 65oC). This means that the storage barrel needs to have a heating element and good insulation.
Regular monitoring of pH and top-ups are required and the solutions need replacing every 2 - 6 weeks (although some farmers do it less frequently).
Tips on Getting the Best Result
Commercial re-use systems are available but most examples in Australia have been put together by farmers and chemical supply companies on a case-specific basis.
Pros and Cons
Permanent water and chemical savings (and power too). Can use the best quality of water available for plant wash.
Difficult to automate and / or integrate into existing automated systems. Heating costs for keeping alkali hot can be substantial.
Issues in Making it Happen
Manual labour required, OH&S issues with storage of wash chemicals.
Nil - may improve this.