Synergistic effect of activated charcoal and chitosan on treatment of dairy wastewaters

This research investigated the feasibility of using hybrid system based on coagulation and adsorption for high-strength dairy wastewater treatment. Activated charcoal was used a non-toxic adsorbent and chitosan as a natural coagulant for the removal of odor, chemical oxygen demand (COD), total nitrogen (TN), and total phosphorous (TP) from raw dairy effluents. The surface morphology of the adsorbent and coagulant were characterized by scanning electron microscope (SEM). Bench-scale jar test experiments were conducted to evaluate the performance of the integrated treatment system to treat real wastewater with different experimental conditions. Results of the study showed that about 68% and 74% COD was removed by using adsorption and coagulation method respectively. However, a high COD removal efficiency of 90% was achieved, when the coagulation process was coupled with the adsorption process. An in-depth analysis of contaminants present in the dairy effluents after treatment were studied by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The obtained results demonstrated that the organic compound like lipids, carbohydrates and proteins were drastically reduced which in turn lowered the COD level by employing the hybrid treatment system. The above outcomes suggested that combining naturally occurring sorbents and coagulants can greatly enhance the dairy wastewater pre-treatment performance in small scale treatment plants.