Biodegradation and fate of linear alkylbenzene sulfonate in integrated fixed-film activated sludge using synthetic ‎media

Abstract

a b s t r ac tLinear alkylbenzene sulphonate (LAS) is widely used for household and industrial purposes while influencing negatively on the environment. Present paper aimed to study LAS biodegradation among different loading rates and fate of LAS in integrated fixed-film activated sludge (IFAS) using synthetic media. A synthetic wastewater among three LAS loading rates with LAS concentrations of 5, 12 and 20 mg/L was investigated within an operative period of 111 d. In doing so, a kinetic model was developed to explain the biodegradation rate of LAS. Finally, the obtained data were analyzed by analysis of variance statistical test. The mean removal efficiency of LAS among three LAS loading rates were 92.32% ± 2.81%, 95.55% ± 2.74% and 96.22% ± 2.74%, respectively. Nevertheless, in terms of total removal efficiency of LAS, the contributions of LAS biosorption in sludge among the three LAS loading rates were 21.3%, 34.2% and 48.5%. The mean removal efficiency of chemical oxygen demand (COD) in among three LAS loading rates were 92.17% ± 4.32%, 91.53% ± 3.34% and 90.91% ± 2.98%, respectively. Moreover, the higher LAS loading rate, the higher removal efficiency of LAS (p ≤ 0.001) and the lower COD removal efficiency (p ≤ 0.001). The results of Michaelis-Menten model for biodegradation kinetics showed that the LAS biodegradation follows the first-order reaction kinetics (R 2 = 0.9949). In addition, biodegradation kinetic and removal efficiency of LAS showed that following the increased concentration of LAS among different loading rates, the LAS biodegradation rate was increased. Therefore, IFAS system is argued to be applicable for wastewater treatment in low and high concentrations of LAS up to 20 mg/L.

Removal of Suspended Solids Using Pumice Stone in Integrated Fixed Film Activated Sludge Process

“…As for the subsequent periods, the loading increased and the yield decreased and became lower than 83%. Fig ( 3), ( 4), ( 5), (6), and (7) show the effect of the change in the organic loading rate on removal SS when using pumice stone with a filling ratio 0, 4, 10, 20, 25%, respectively. The maximum organic loading rate was (1.1884, 1.2144, 1.9432, 2.7768, 3.3141)g BOD /l.d, at each stage.…”

“…This system provides more resistance against organic and hydraulic shock load; besides, it has more flexibility and higher efficacy than other activated sludge processes (3,4) The IFAS system is a good option to upgrade the Activated Sludge System especially in case of facing scarcity of land and provides higher removal efficiency of COD and nutrients relative to conventional activated sludge. It also possesses a lower retention time, higher hydraulic load, and less tank volume (5,6). In the present study, a local substance "pumice stone" with a surface specificity of 224 m 2 / m 3 was used as a fixed biological carrier in the aeration tank over 253 days, with different filling ratio of 0%, 4%, 10%, 20%, and 25% when the organic loading changed from 0.92±0.0384 to 3.4 ±0.0706 gBOD / l.d .…”

Removal of Suspended Solids Using Pumice Stone in Integrated Fixed Film Activated Sludge Process

“…As for the subsequent periods, the loading increased and the yield decreased and became lower than 83%. Fig (3), (4), (5), (6), and 7show the effect of the change in the organic loading rate on removal SS when using pumice stone with a filling ratio 0, 4, 10, 20, 25%, respectively. The maximum organic loading rate was (1.1884, 1.2144, 1.9432, 2.7768, 3.3141)g BOD /l.d, at each stage.…”

Developing a system dynamics model for prediction of phosphorus in facultative stabilization ponds

“…Wastewater is treated in WSPs as a result of algae and bacteria symbiosis and others complex ecosystem such as virus, protozoa, rotifers, insects, crustaceans, and fungi (Kehl et al 2009; Olukanni and Ducoste 2011). Organic materials in wastewater are biodegraded by aerobic bacteria and dissolved oxygen required to bacteria were provided by algal photosynthesis (Eslami et al 2017; Martin and Vanrolleghem 2014). Facultative ponds (FPs) are very complex because of the three anaerobic, aerobic and facultative zones (Ebrahimi et al 2010).…”