Superconducting high gradient magnetic separation for purification of wastewater from paper factory

Purification of wastewater from paper factory was attempted by superconducting high gradient magnetic separation (HGMS) both in laboratory scale and pilot-plant scale experiments. Magnetite and some kinds of iron hydroxide particles were used as scavenging materials for suspended substances (SS) and organic dye molecules included in wastewater. The chemical oxygen demand (COD value) was used as a measure of purification of the wastewater. Optimum dosage of the scavenger was examined. Model wastewater was also prepared and tested in order to elucidate the mechanism of adsorption of the organic materials onto the scavenging particles. The obtained results showed that the wastewater was successfully purified by HGMS both in a laboratory scale and a pilot-plant scale. The apparatus modifications of magnetic filters and flow path were also made to accomplish the purification system for the practical use. The results can allow us to promote a scale-up design for greater capacity of the treatment of wastewater.