Pilot-scale treatment of textile wastewater by combined biological-adsorption process

Abstract

A B S T R A C TDye pigments are the main pollutants in textile industry wastewaters. Dye reduction or completely removal from the wastewater is the biggest challenge in this industry. This study was carried out by combined biological-adsorption system. Activated sludge with extended aeration as biological and slow filtration as adsorption process was used. In activated sludge system, different hydraulic retention times (HRT) were investigated (18, 24, 30, and 36 h). The results revealed that by increasing the HRT, the biological system could remove about 80% of chemical oxygen demand (COD) and 33.5% of dye pigments. Then the effluent of the biological system comes to the slow filtration pilot to remove the dye completely. In this stage, beside of granular activated carbon (GAC) that is very high-cost adsorbent, saw dust and inorganic soils, such as kaolin and talc were tested simultaneously. According to the results, the bed that contains GAC by 91%, kaolin 78%, saw dust 64.4%, and talc 55.5% removal showed the highest efficiency, respectively. Adsorption data were modeled using Langmuir and Freundlich isotherms. The analysis showed that Freundlich isotherm reasonably fit the experimental data for all the adsorbents. Finally, the combined biological-adsorption system could remove about 98.2, 95.6, 92.9, and 91.1% of COD by using GAC, kaolin, saw dust, and talc as an adsorbent, respectively. By considering the cost-benefit analysis and availability of the adsorbents, saw dust, and inorganic soils, such as kaolin can be the alternative choice instead of GAC to combine with activated sludge system in order to recycle the effluent of the textile industry wastewater and save huge amount of water.

Influence of aniline and antimony on micro-oxygen hydrolysis and acidification processes in printing and dyeing wastewater treatment

“…Improper discharge of printing and dyeing wastewater may endanger aquatic environment and human health. With current strict discharge standards, new requirements have been put forward for the treatment of printing and dyeing wastewater accordingly (Mirbagheri and Charkhestani 2015, Periyasamy et al 2018, Ramlow et al 2017).…”

Removal of textile azo dyes with mixed biomass of Aspergillus niger and orange peel (Citrus sinensis L. Osbeck)

“…Considering the great importance of reuse of agro-industrial waste, a number of studies have indicated the use of biomass to adsorb pollutants with significant results, demonstrating high efficiency in the removal of pollutants even in small quantities [16]. The adsorption capacity of these nonconventional adsorbents is due to the presence of biopolymers such as polysaccharides, lignin, hemicelluloses and cellulose [17].…”