Jeremi Naumczyk, Piotr Marcinowski, Piotr Wiliński, Jan Bogacki
In this study the coagulation process of five cosmetics wastewater types has been investigated. All samples were collected from big cosmetic factory in Poland. Due to changeable production profile, also significant changeability of the wastewater composition and the concentration of pollutants were observed. COD values of raw wastewaters samples 1, 2, 3, 4 and 5 were as follows: 7293, 3241, 3241, 5132 and 1089 mg/l, respectively. Before coagulation easily settleable suspended solids were removed by 30 min primary sedimentation. After sedimentation COD values were decreased to 1134, 2512, 3241, 1858 and 1089 mg/l, respectively. Coagulation with Al2(SO4)3 at pH 7.0 and FeCl3 at pH 6.0 and 9.0 allowed to achieve COD removal in the range of 33.0–63.5%. The effect of coagulation was better for the samples of lower contents of easily settleable suspended solids and higher content of fine suspended solids. The best effects of COD removal by coagulation achieved for investigated wastewaters were as follow: sample 1 – 39.2%, by Al2(SO4)3 and FeCl3 at pH 9.0; sample 2 – 54.8%, by FeCl3 at pH 6.0; sample 3 – 60.0%, by Al2(SO4)3; sample 4 – 33.3%, by Al2(SO4)3; sample 5 – 63.5%, by FeCl3 at pH 6.0. The differences in coagulants effectiveness were not significant. Flopam flocculant improved the effect of coagulation – shortened the clarification time from 60 min to 5 min, reduced the coagulant doses by about 50 mg/l and increased COD removal. In the coagulation assisted by Flopam flocculant, Al2(SO4)3 proved to be the best coagulant for sample 3 (62.5%), FeCl3 at pH 6.0 was the best for sample 2 (54.8%) and sample 5 (63.9% – the best result of all) and FeCl3 at pH 9.0 for sample 4 (50.0%). The best effect of coagulation was achieved for sample no 5, which had no easily settleable suspended solids. The total effect of COD removal, including primary sedimentation and coagulation ranged from 63.9 to 90.6%. GC-MS analysis allowed to identify 110 compounds. The predominant compounds identified by GC-MS were: cyclopentasiloxane, decamethylcyclopentasiloxane and synthetic musk – galaxolide (HHCB). HHCB concentration was decreased in the coagulation by 87.3–92.2%. The degree of other compounds removal varied in the range 0–99.4%.
oczyszczanie ścieków; proces koagulacji
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