Azolla Filiculoides and Demospongiae as Eco-Friendly and Affordable Adsorbents for the Treatment of Dairy Wastewater: Application of Central Composite Design

There are soluble organics, insoluble trace organics, suspended solids, nitrogen, phosphorous, sodium, and potassium in the wastewater of the dairy processing unit, which lead to unpleasant taste and smell and turbidity of water. The present study investigates the ability of Azolla filiculoides and demospongiae for the treatment of dairy wastewater from sodium, potassium, and phosphorus ions. The effect of different parameters, including contact time, pH, temperature, and kind of adsorbent on the residual values of Na, K, and P in aqueous solutions was investigated using Central Composite Design (CCD). The minimum residual value of Na was assigned to the sponge adsorbent with a time of 6 h, pH of 6, and temperature of 22 ºC. The sponge with a time of 11 h, pH of 7, and temperature of 23 ºC was selected as the best condition for the removal of K. Also, Azolla revealed maximum removal of P with a time of 6 h, pH of 8, and temperature of 24 ºC. In conclusion, Azolla filiculoides and demospongiae can be considered as facile, cost-effective, environmentally friendly, and efficient adsorbents for the treatment of dairy wastewater from various pollutants.