Automatic Dishwashing Tabs

In a recent Eco-Efficiency Analysis BASF has investigated the use of new amino-carboxylates chelating agents against phosphate in household automatic dishwashing (ADW) tabs under European conditions with respect to their environmental impact.

Infographic showing customer benefit vs. alternative system

The environmental categories considered in the analysis are energy consumption, resources consumption, emissions, human- and eco-toxicity, risk and land use. The analysis considered the production, use and disposal of 100 ADW tabs with three alternative formulations. The weight of the three alternative tabs, based respectively on MGDA (Alanine, N,N-bis(carboxymethyl)-, trisodium salt), GLDA (Glutamic acid, N,N-bis(carboxymethyl)-tetrasodium salt) and STPP (sodium tripolyphosphate), is kept constant. Sodium sulfate and sodium citrate are eventually added for this purpose. The composition of the formulations is shown in table below. The chelating agents are used as powders, their active content is considered according to the technical information and safety data sheet available: STPP 100%, MGDA 86% and GLDA 74%.

  MGDA Tabs STPP Tabs GLDA Tabs
MGDA 17,4% - -
GLDA - - 26,2%
STPP - 50,0% -
Sodium citrate 23,3% - 23,3%
Sodium sulfate 9,3% - 0,5%
Sodium carbonate 20% 20% 20%
Surfactants, polymers, bleaching 30% 30% 30%

The results demonstrate that the new aminocarboxylates have less impact on the environment when compared to phosphate. The differences are derived from resource consumption associated with the production of phosphate, as well as from impact of water emissions and solid waste.