A novel process to recycle the highly concentrated calcium and chloride ions in the gelatin acidification wastewater. (1st July 2018)

• Record Type: Journal Article
• Authors: Wang, Guan; Yu, Ningning; Guo, Yong
• Is Part Of: Journal of cleaner production. Volume 188(2018)
• Page Start: 62
• Page End: 68
• Publication Date: 2018-07-01
• Subjects: Gelatin acidification wastewater -- Cleaner production -- Recycling -- Hydrochloric acid -- Calcium sulfate; Factory and trade waste -- Management -- Periodicals; Manufactures -- Environmental aspects -- Periodicals; Déchets industriels -- Gestion -- Périodiques; Usines -- Aspect de l'environnement -- Périodiques; 628.5
• DOI: 10.1016/j.jclepro.2018.03.215
• Languages: English
• ISSNs: 0959-6526

Abstract

Abstract: The effluents of the gelatin acidification process are highly complex and difficult to treat, especially in the presence of high concentrations of Cl −, which not only pollute the environment, but also seriously hamper the development of bone gelatin enterprises. In this study, a novel cleaner production process for recycling the highly concentrated calcium and chloride ions is proposed to basically solve the problem of acidification wastewater management in the gelatin industry. In this process, wastewater from the acidification process is firstly reacted with sulfuric acid to generate calcium sulfate and then the effluent is further treated by distillation. The outcomes demonstrate that the concentration and recycling rate of hydrochloric acid in the distillate could reach close to 6.1% and 75% under the optimal conditions, and the recycled hydrochloric acid could be reused in the acidification process. Meanwhile, the emission of wastewater could be reduced about 70%. The purity (98%) and composition (calcium sulfate hemihydrate) of the calcium sulfate were explored by X-ray photoelectron spectrometer and X-ray diffraction. The output of CSH was 75 kg per tonne of wastewater (11.5T per tonne of gelatin). Additionally, analyzing the operational cost of this process shows that about the operational costs could be halved. In conclusion, this novel process minimizes the wastewater discharge and achieves the cleaner production in gelatin industry. Highlights: The high concentration of Cl − is regenerated as hydrochloric acid, which could be returned to the acidification process. The new process can produce CSH, with purity up to 98% and an output of 75 kg per tonne of wastewater. The discharge of wastewater is reduced by 70%, and the concentration of harmful ions is reduced greatly. The operating costs are reduced about a half.