The method comprises: mixing an adsorbent reagent (31) with water to produce a water-adsorbent reagent mixture and adsorbing the pollutants in the water； subjecting the water-adsorbent reagent mixture to a liquid-solid separation process and producing treated water (90) and sludge (100)； contacting the water or treated water with living aquatic organism (220), where the value of property of the living aquatic organism is correlated to the concentration of the pollutants in the water or treated water； and evaluating the value of the property of the living aquatic organism. The method comprises: mixing an adsorbent reagent (31) with water to produce a water-adsorbent reagent mixture and adsorbing the pollutants in the water； subjecting the water-adsorbent reagent mixture to a liquid-solid separation process and producing treated water (90) and sludge (100)； contacting the water or treated water with living aquatic organism (220), where the value of property of the living aquatic organism is correlated to the concentration of the pollutants in the water or treated water； evaluating the value of the property of the living aquatic organism； adjusting the quantity of adsorbent reagent mixed with the water as a function of the value of the property of the living aquatic organism； chemically oxidizing the water during the adsorbing process or upstream of the adsorbing process； injecting the adsorbent reagent into the water to be treated when the value obtained is greater than or equal to a predetermined threshold； and controlling the quality of the treated water produced by determining an information representative of the quality of the treated water as a function of the value resulting from evaluating the value of the property of the living aquatic organism. The quantity of adsorbent reagent mixed with the water is proportional to the value obtained by evaluating the value of the property of the living aquatic organism. The step of adjusting the quantity of adsorbent reage
