Packed-Cage RBC with Combined Cultivation of Suspended and Fixed-Film Biomass

Abstract

The situation in the treatment of wastewaters from small sources in Czechoslovakia has been discussed and two types of manufactured rotating biological contactors have been described. The evaluation of RBCs' operation showed the main disadvantages of the contactors with conventional discs, viz. the low 0C and low mixing effect. In a newly designed RBC, the discs or packets of discs were replaced by a cage packed with a random medium. The cage was equipped with tubular aeration and mixing elements. The long-term tests with a pilot-plant and a full-scale unit using synthetic as well as municipal wastewaters proved the ability of the packed-cage RBC to achieve a low effluent BOD with such organic loadings when the effluent from the conventional RBCs already deteriorated. Besides the BOD removal the 0C of the packed-cage RBCs was tested to verify the possibility of the combined cultivation of suspended and fixed-film biomass. On the basis of results presented here, a new package wastewater treatment plant for about 500 PE will be designed.

Comparison of mass transfer efficiency in horizontal rotating packed beds and rotating biological contactors

“…For P / V L values (∼60 W m −3 ) similar to those in Zlokarnik's work,11 and using eqn (6) to calculate k L a the OTE works out to be 0.3 kg kWh −1 . In the case of the h‐RPB, the study by Wanner et al 6 gives the OTE values for a pilot‐scale and full‐scale unit as 0.9 kg kWh −1 and 0.63 kg kWh −1 respectively. A comparison between these values clearly establishes the higher efficiency of the h‐RPB for full‐scale units.…”

“…Also, for lower influent flowrates (<1 m 3 h −1 ) the authors have reported completely mixed flow conditions. Wanner et al 6 carried out pilot plant‐ and full‐scale studies on aerobic h‐RPBs. They reported removal efficiencies of 92–97% in the case of the pilot plant (0.33 m cage diameter, 0.85 m length).…”

“…From the above review it is clear that the h‐RPB has shown high (80–97%) removal efficiency for different wastes even in case of full‐scale studies. But information on the power consumption is limited to only one study 6. Similarly information regarding the mass transfer coefficients is scanty/absent.…”

Rotating Biological Contactors: A Review

“…This compares well with the typical values of surface area in conventional reactors 5 such as packed columns (25-200 m 2 /m 3 of reactor), bubble columns (25-500 m 2 /m 3 of reactor), and stirred reactors (100-1000 m 2 /m 3 of reactor). Wanner et al 6 developed an RBC system consisting of a cage filled with random packings, which is shown schematically in Figure 2. The cage was constructed with wire mesh netting and was filled with cylindrical plastic elements.…”

“…The cage was constructed with wire mesh netting and was filled with cylindrical plastic elements. Wanner et al 6 reported that their entire assembly provided a contact area of 10.5 m 2 . For the dimensions given in their paper, the interfacial area is 100 m 2 /m 3 of reactor volume, which is the same as that of standard-density media (Figure 1B).…”