Abstract:
The dyeing processes of the community owned hand-made cotton weaving industry was studied. The prohibited azo dyestuffs were analyzed and the appropiatedwastewater treatments by chemical methods were studied. The colored wastewater generated from a single color dyeing was less than 200 liter and the dyeconcentration was less than 100 mg/L. The prohibited amines of 80 colors (brand B and L) were analyzed by reduction cleavage with sodium dithionite at pH of 6 and70?C for 30 minutes. The solution was filtered and the amine compounds were adsorped by extrelute hTT and then were extracted with tert-butyl methyl ether andevaporated. The prohibited amines were analyzed by GUMS. The three wastewater treatment methods studied included 1) Fenton's reaction 2)Coagulation with aluminium sulfate (Alum) and 3) Coagulation with alum and Zetag(Coagu1ant aid). First, the treatment of brand D dyestuffs (16 colors) at theinitial concentration of 100 mg/L by Fenton's reaction was studied. It was found that Fenton's reaction could remove more than 90% using the concentration (aftermixing) of hydrogen peroxide and fmous sulfate = 7 . 0 ~ 1 0m~g/ L and 0.476 mg/L, respectively. These optimal concentrations could be applied for the brand Bdyestuff (3 1 colors). Second, the treatment of black, red and blue colors (brand D, B and L) for the total of 9 samples wastewater prepared by dissolving it with thedeionized water (DI) and the ground water (GW) obtained from "Pijit Hand Weaving Group located in Natapho village Tumbol Banbung, Auphur Ban Rai,Uthaithani Province". The effectiveness of Fenton's reaction was compared to the coagulation. It was found that the optimum pH of both treatment methodes was not difference for thecolor water prepared from the same solvent (DI or GW). If the solvent was GW and DI, the optimum pH was 5 and in the range of 5-8 respectively, for both treatment method.The optimum chemical concentrations (after mixing) for the ground water dissolved color were H202 = 7.0~10-m~g /L and Fe2S04 = 6.3~10-m~g /L for the Fenton'sreaction, and alum = 153.80 mg/L with no pH adjustment for the coagulation. The treatment of three color water dissolved with GW in the 400 liter reactor wasstudied using the alum coagulation with Zetag method. All color could achieve more than 95% removal of the initial concentration of 100 mg/L. The small flocgenerated from the blue color treatment resulting in a longer sedimentation period. The color sludge could be filtered out using the fine sand which is widely avalableat the construction material shops.