DETERMINATION OF THE OPTIMUM pH OF WATER FLOCCULATION IN RIO CUIABÁ THROUGH JAR TEST

Background: Clean water is essential for human health and the environment. Removing flakes during water treatment is crucial to eliminating suspended particles and contaminants. Optimum pH plays a key role in the efficiency of flocculation, allowing the formation of larger and denser flocs. Adjusting the pH correctly helps to neutralize the electrical charges of the particles and optimize the interaction between them. This results in more efficient removal of flakes and particles, improving the quality of the treated water. Aim: This study aims to determine the optimal pH for flocculation of water in Rio Cuiabá through the Jar Test. Methods: The Jar Test was used to determine the optimal pH of water flocculation in Rio Cuiabá, located in the city of Cuiabá - MT, Brazil. Water samples were mixed in 6 vials with different doses of coagulant, shaken and observed to identify the most effective dosage and pH. The test was carried out using two different coagulants: aluminum sulfate and polyaluminium chloride (PAC). Results and discussion: For the test with aluminum sulfate, the best pH values were found in flasks 4 to 6, where the pH was between 6.37 and 6.5, since, in these cases, the turbidity was almost null or null. In the case of PAC, the best pH was the neutral one, because at pH equal to 7.16 there was the lowest turbidity. Proper pH adjustment affected the efficiency of coagulation and flocculation, influencing the removal of suspended particles and the quality of treated water. The optimum pH promoted the formation of larger and denser flocs, improving particle removal efficiency. Water turbidity was also influenced by pH, and appropriate adjustments can facilitate particulate removal during coagulation and flocculation processes. Conclusions: The determination of the optimal flocculation pH is crucial to improve the quality of treated water, especially in relation to the removal of suspended particles.