In this studies gamma and electron beam irradiation was used to treat textile waste water. Comparisons between both types of irradiation in terms of effectiveness to degrade the pollutants present in textile waste water were done. Prior to irradiation, the raw wastewater was diluted using distilled water to a target concentration of COD 400 mg/l. The sample was irradiated at selected doses between the ranges of 10 kGy to 100 kGy. The results showed that irradiation has significantly contributed in the reduction of the highly colored refractory organic pollutants. The COD removal at the lowest dose, 10 kGy was reduced to 390 mg/l for gamma and 400 mg/l for electron beam. Meanwhile, at the highest dose, 100 kGy, the COD was reduced to 125 mg/l for gamma and 144 mg/l for electron beam. The degree of removal is influenced by the dose introduced during the treatment process. As the dose increased, the higher the removal of organic pollutant was recorded. However, gamma irradiation is more effective although the differences are not significant between gamma and electron beam irradiation. On the other hand, other properties of the wastewater such as pH, turbidity, suspended solid, BOD and color also shows a gradual decrease as the dose increases for both types of irradiation.
Effects of organoclay concentration on the properties of radiation crosslinked natural rubber (NR)/ ethylene vinyl acetate (EVA)/clay nanocomposites were investigated. The NR/EVA blend with a ratio of 40/60 was melt blended with different concentration of either dodecyl ammonium montmorillonite (DDA-MMT) or dimethyl dihydrogenated tallow quarternary ammonium montmorillonite (C20A). Composite of NR/EVA blend with unmodified clay (Na-MMT) was also prepared for comparison purposes. The composites were irradiated with electron beam (EB) at an optimum irradiation dose. The formation of radiation-induced crosslinking depends on the type and concentration of the organoclay used in the preparation of nanocomposites as measured by gel content. Changes in the interlayer distance of the silicate layers with the increase of organoclay concentration were shown by the XRD results. Variation in the tensile properties of the nanocomposites with the increase of organoclay concentration depends on the formation of crosslinking as well as reinforcement effect of the organoclay. Improvement in thermal stability of the NR/EVA blend was also observed with the presence of organoclay.
The combination of irradiation and biological technique was chosen to study COD, BOD5 and colour removal from textiles effluent in the presence of food industry wastewater. Two biological treatments, the first consisting a mix of non irradiated textile and food industry wastewater and the second a mix of irradiated textiles wastewater and food industry wastewater were operated in parallel. Reduction percentage of COD in textiles wastewater increased from 29.4% after radiation to 62.4% after further undergoing biological treatment. After irradiation, the BOD5 of textiles wastewater was reduced by 22.1%, but reverted to the original value of 36mg/1 after undergoing biological treatment. Colour had decreased from 899.5 ADMI to 379.3 ADM1 after irradiation and continued to decrease to 109.3 ADMI after passing through biological treatment.