Biofilm-bacterial communities have been exploited in various biological wastewater treatment processes. The present work is aimed at exploring the possible factors for tailoring biofilm mechanics by introducing divalent cations (Ca²⁺) in the constructed wetland soil. The in vitro investigation of soil samples collected at various retention times revealed that the addition of Ca²⁺ facilitates the formation of well organized patterns of biofilm compared to calcium depleted conditions. Afterwards, Ca²⁺ ions were intentionally introduced into the soil of lab-scale constructed wetland to examine its superior treatment efficiency towards the removal of various chemical and microbiological contaminants. The current work therefore may form a basis to implement theoretical predictions experimentally in a real time existing wastewater treatment technology. Hence, the same approach can effectively be adopted in pilot scale wetland systems as well as other biofilm mediated wastewater treatment technologies.