A Comparative Analysis of the Efficiencies of Pre-ozonation with and without Chitosan and Ferric Chloride in Eliminating Diatoms, Chlorophyceae, and Cyanophyceae from Surface Waters: A Case Study of Mijran Dam Reservoir

The Mijran Dam reservoir is of significant importance as it is used for potable water supply. Many consumers are dissatisfied with the taste and odor of drinking water, which is often caused by compounds from chemical fertilizers, animal manure, pesticides, heavy metals, algae and wastewater. This study examines the effectiveness of pre-ozonation and the application of chitosan and ferric chloride coagulants in removing diatoms, chlorophyceae, and cyanophyceae from the Mijran Dam water reservoir. A laboratory-based experimental methodology was employed to identify algal species and conduct microscopic sample analyses. The experimental framework was meticulously crafted using Design-Expert v13 software, with validation of findings achieved via applying the response surface method (RSM). Statistical scrutiny of the amassed data was executed using SPSS software. The study investigated the influence of various parameters, including the pH level of chitosan (5–10) and ferric chloride (5–10), chitosan concentration (20 to 500 mg/L), ferric chloride concentration (5 to 100 mg/L), ozone pH levels (3 to 11), and injected ozone concentration (2 to 8 mg/L). Pre-ozonation at a concentration of 8 mg/L and a pH of 7 could eliminate approximately 70% of diatoms, 78% of chlorophyceae, and 88% of cyanophyceae. Ozonation (2 mg/L) used along with chitosan (500 mg/L) at a pH of 10 enhanced algal removal, leading to the elimination of approximately 77% of diatoms, 81% of chlorophyceae, and 92% of cyanophyceae. Ozonation (2 mg/L) in conjunction with ferric chloride (75 mg/L) at a pH of 10 resulted in the elimination of diatoms, chlorophyceae, and cyanophyceae at rates of approximately 79%, 83%, and 97%, respectively. Ozonation, employed together with ferric chloride and chitosan enhanced efficiency while concurrently reducing ozone demand.