Natural microalga species from desalination concentrate evaporation pond was used to reduce dissolved ions from a high level conductivity of desalination concentrate and leachate of anaerobic digested sludge (LADS) compost The initial microalgae-to-conductivity ratio was in the range of 0.0008 to 0.0010 g/(L mu S/cm). LADS was supplied as nutrients. Carbon dioxide from the environment was dispersed into the growth medium. Mass conductivity reduction (Y) of 27.6-33.6% was achieved in 15 days. Y is directly linear with mass microalgae-to-conductivity-ratio (X) as Y = 30930X + 8.9182 with R-2 0.996: p < 0.001 in three different studies with two different species. Reduction was on the order of HCO3-, NH3N, NO3N, total P, Ca2+, SO42-, non-Ca2+ and multi-valent cations, and Cl- with mass reduction percentage 83.9-88.0, 69.0-77.6, 63.6-57.1, 59.1-70.7, 47.3-59.4, 12.6-19.0,4.5-24.5, and 6.3-18.2, respectively. Reduction sequence follows C, N, P, Ca2+, SO42-, and Cl- as primary-, macro-, and micro-nutrients of microalga composition. Carbon species, H2CO3* was dominant in the growth medium. (C) 2014 Elsevier B.V. All rights reserved.