Case Studies in Chemical and Environmental Engineering (Dec 2023)
Flocculant capacity of hydrocolloid extracted from high Andean algae (Nostoc sphaericum) in the treatment of artificial wastewater: An approach
Abstract
The treatment of wastewater of domestic sources is composed by a series of procedures for the removal of pollutants, and involves the use of chemicals, for example for the coagulation-flocculation process, and not often, the use of chemical products is advantageous. This investigation aimed in evaluate the effect of different dosages of the flocculant hydrocolloid extracted from a high Andean algae (Nostoc Sphaericum) in the treatment of artificial wastewater in different pH. The hydrocolloid was extracted by atomization and the functional groups were identified by Fourier Transform Infrared Spectroscopy (FTIR) and the zero point charge (ZPC), ζ potential, and particle size were also determined. On the other hand, tests were carried out to simulate the coagulation-flocculation process applying doses of the hydrocolloid coagulant Nostoc Sphaericum/Aluminum Sulfate (HN/SA). The percentage of pollutants removal from wastewater was calculated by the variation of physical and chemical parameters before and after treatment with hydrocolloid. We used a 22 factorial design and assessed its effects using a statistical analysis ANOVA with a significant level of 5 %. The results showed that HN exhibited functional groups characteristic of polysaccharides, ZPC of 7.67, and ζ potential of higher stability in an alkaline medium. In the acid medium, we observed that turbidity was removed in 51.47 %, color 73.96 %, COD 95.41 %, TOC 46.67 %, while TDS reduced in 20.45 %, the BOD5 was 22.73 % and TSS 65.98 % in alkaline medium. The correlation analysis highlights that the organic matter in the artificial wastewater exerted a substantial influence on the flocculant capacity of the hydrocolloid, especially given the high biodegradability of the artificial wastewater. This leads to the conclusion that HN is efficient in removing contaminants from artificial wastewater, with pH identified as the most influential variable.
