The effectiveness of a treatment system for the decolorization of dyeing wastewater was investigated.It was discovered that a combination of coagulant,carboxymethyl chitosan（NOCC） and a coagulant aid,PAM,yielded an effective treatment for wastewater since almost complete decolourization was achieved and 90% of chemical oxygen demand（COD） was reduced.The color concentration of dye solutions was measured by visible spectrophotometry.Parameters such as the effect of pH,the effect of coagulant and coagulant aid dosages have been studied.The optimum pH value and dosage for treatment were found to be pH=2.3,480mg·L-1 for NOCC and 4-8mg·L-1 for PAM respectively.
