Salinity effects on biological treatments

Abstract

High salinity environments can cause the denaturation of microbial enzymes and the destruction of the cell structure. In order to withstand these effects, microorganisms are able to develop mechanisms to both maintain the osmotic pressure balance inside the cells with the bulk liquid and retain water. Organic matter and nitrogen can be removed from high salinity effluents by means of biological processes, once microorganisms are previously adapted to the salt presence, but phosphorus removal efficiency decreases notably under saline conditions, even applying long acclimation periods or using a marine inoculum. Sudden fluctuations of wastewater salt concentration are the worst scenario for biological treatment systems since they cause the loss of pollutant removal efficiency that cannot be avoided even using halophilic microorganisms.