Efficiency of Packed Cage RBC System for Treatment of Wastewater Containing Surfactants

Abstract

The chemical oxygen demand (COD) and five-day biological oxygen demand (BOD5) removal efficiencies of a packed cage rotating biological contactor (RBC) system under a hydraulic retention time (HRT) of 16 h declined from 93.90% to 78.58% and 78.61% and 96.27% to 84.83% and 87.93%, respectively, with an increase of sodium dodecyl sulphate (SDS) and triton X-100 loading from 0.00 to 1.25 mg/m 2 ⋅d. Reactor no. 1 of the system changed to anaerobic when the system was operated under an HRT of 8 h with surfactant loading of up to 2.55 mg/m 2 ⋅d. However, reactor no. 2 of the system was aerobic and the dissolved oxygen was higher than 3.00 mg/L. The study showed that this type of packed cage RBC system could be applied for treating the cosmetic industry wastewater with surfactant loading of up to 2.55 mg/m 2 ⋅d under an HRT of 8 h.

Effect of Ni2+ and Pb2+ on the efficiency of packed cage rotating biological contactor system

“…The packed cage RBC system [7,8,10,11] is an aerobic moving bio-film reactor, modified from the original RBC system [4] to increase both the surface area of the bio-drum and bio-film mass of the system as shown in Fig. 1A.…”

“…The wastewater from such industrial parks contains various types of pollutants including both organic and inorganic pollutants (heavy metals: HM) [3,5,6]. So, the selection of a wastewater treatment system should be carefully considered [1,4,7,8]. Theoretically, a biological wastewater treatment process is suitable for organic wastewater, but inorganic wastewater is usually treated by a chemical treatment process [1,4].…”

“…Two types of aerobic-biological treatment systems, suspended growth (activated sludge system) and attached growth (rotary biological contractor: RBC and packed cage-RBC), are normally applied for the treatment of organic wastewater containing some toxic substances such as chlorine, surfactants, phenolic compounds and so on [5,9]. The advantages of the RBC and packed cage-RBC systems are low energy consumption and high nitrogen removal efficiency [4,7,8]. However, the growths and activities of nitrifying and denitrifying bacteria are repressed by HM as mentioned above [5,6,9].…”

“…So, the effects of the types and concentrations of HM on the nitrogen removal efficiency of the packed cage RBC system should be investigated. Our previous works [8,10,11] reported that the packed cage RBC system showed high nitrogen removal efficiency with low energy consumption as a result of the high populations of nitrifying and denitrifying bacteria [8]. The system was also applied for wastewater containing surfactants, especially sodium dodecyl sulfate and triton X-100, without any effects on the bio-film growth and performance (the bio-film was not peeled off by the effect of the above surfactants during operation) [10].…”

“…However, HM contamination in the wastewater might affect the system efficiency and performance [7,10,11]. In this study, the effects of Ni 2+ and Pb 2+ concentrations and loadings on the packed cage RBC system efficiency and performance were carried out.…”