Treatment of chitin effluents by coagulation–flocculation with chitin and aluminum sulfate

Chitin is a natural copolymer found in crustacean shells and has potential for use in a wide range of faculties. During the chitin obtainment process, effluents with high organic charge are generated. These should be treated before discharge in order to avoid environmental problems. This work aimed to investigate the treatment of effluents from chitin obtainment process using chitin (CH) and aluminum sulfate (Al2(SO4)3) as coagulants. The effects of coagulant type (CH and Al2(SO4)3), coagulant concentration (150 and 300 mg L−1) and pH (6.0 and 8.5) were evaluated by a full 23 experimental design. The considered responses were: total solids reduction (TSR), suspended solids reduction (SSR) and turbidity reduction (TR). It was found that the use of 300 mg L−1 of Al2(SO4)3 under pH 6.0 or 8.5 favored the treatment of effluents from chitin obtainment process. The proposed treatment provided reductions of 20, 89 and 85% in the total solids, suspended solids and turbidity respectively.