Improving the efficiency of saline wastewater treatment plant through adaptation of halophilic microorganisms

Abstract

In the urban wastewater treatment plant of Bandar Torkaman, total input of solvent solids is about 8-9 g L-1 and the electrical conductivity is 14,600 µs cm-1. High salt concentrations cause some problems in biological treatment process. Therefore, this study was designed to improve the effluent of saline wastewater treatment plant in Bandar Torkaman by adaptation of halophilic microorganisms. We designed a pilot plant considering the size of the current wastewater treatment plant and installed an RBC system. Effective parameters were evaluated and halophilic microorganisms in both plants were cultured and identified according to the standard methods in both the treatment plant and the pilot plant. The average electrical conductivity of sewage was 12,000 µs cm-1. We found Salinibacter and Adhaeribacter species were able to grow in high salt concen trations. Considering the results of the present study, we conclude that the attached growth systems have more efficiency for saline wastewater treatment than the suspended purification systems. In addition, pH (R² = 0.344) and rotational velocity (R² = 0.094) had the least effect on the efficiency. Changing the system of aerated lagoon and suspended growth to attached growth increases the growth of halophilic microorganisms, thus increasing the efficiency of organic matter removal in wastewater treatment plants.