In order to evaluate the performance of a two-compartment electrodialysis process used to concentrate ammonium lactate from kitchen garbage fermentation broth, we made experimental study to investigate the effect of initial dilute solution concentration (C-di) and flow-rate on limited current density (LCD), the effect of current density, Cdi and operating modes on concentration of ammonium lactate, and found that LCD increases rapidly first, then increases slowly after it reaches 2.55 A/dm(2) with an increase in Cdi; LCD increases almost linearly with the flow-rate; an increase in Cdi helps to increase the current efficiency, but causes a decrease in the recovery ratio of ammonium lactate from 85.57% to 82.66% with an increase in C-dj from 0.35 to 0.45 mol/L at 2.5 A/dm2; the use of constant current followed by the use of constant voltage is more effective than the use of constant current or constant voltage all the way through; ammonium lactate is concentrated from 0.10 to 0.396 mol/L with the use of constant current followed by the use of constant voltage for 6 h. The results indicated that two-compartment electrodialysis is an effective and useful process used to concentrate and purify ammonium lactate from kitchen garbage fermentation broth. (c) 2008 Elsevier B.V. All rights reserved.