Applied Microbiology and Biotechnology
Electronic Supplementary Material
Treatment of Ferrous-NTA based NOx Scrubber Solution by an Up-flow Anaerobic Packed Bed Bioreactor B. Chandrashekhar, Nidhi Sahu, Heena Tabassum, Padmaraj Pai, Amruta Morone, Ram. A. Pandey* Environmental Biotechnology Division, CSIR-National Environmental Engineering Research Institute, Nehru Marg, Nagpur-440020, Maharashtra, India
*Corresponding Author: Dr. R.A. Pandey, Scientist & Head, EBD, CSIR-NEERI, Nagpur-20,
Email :
[email protected], Phone No. : +91-712-2240097, Fax: +91-712-2249900
Mean Cell Residence Time (MCRT) in the UAPBR The mean cell residence time was calculated to determine the separation between the biomass and medium flow in upward direction. Generally, mean cell residence time is dependent on several factors such as biomass growth and death rates, medium flow, void and effective volume etc., and is mostly calculated during the steady state. Based on material balance around the UAPBR, rate of biomass loss from UAPBR was calculated using the following equations: Rate of biomass generation = Rate of biomass waste (for steady state condition) Xwaste = CXs * Vs
--------------- (1)
Rate of biomass inlet, Xinlet = CXi * Vi
--------------- (2)
Rate of biomass outlet, Xoutlet = CXo * Vo
--------------- (3)
where, CXs (g.L-1) is the concentration of biomass settled in the UAPBR bottom, Vs (L.h-1) is the removal rate of the settled biomass, CXi (g.L-1) is the concentration of biomass in the influent stream, Vi (L.h-1) is the flow rate of influent stream, CXi (g.L-1) is the concentration of biomass in the effluent stream, V0 (L.h-1) is the flow rate of effluent stream (which is equal to Vi) Using material balance, Rate of biomass loss, Xloss = (Xwaste) + (Xoutlet) – (Xinlet)
------------ (4)
The total suspended biomass present in the UAPBR medium was calculated as the geometric mean of biomass concentration present in the bottom and effluent, while the total attached biomass on the packing material was estimated using gravimetric method periodically. The sum of both gave the total biomass present in the UAPBR. Thus, the mean cell residence time (MCRT) can be calculated as follows:
MCRT =
Total biomass in the UAPBR Rate of biomass loss
------------ (5)
Results The following figure (Fig S1) shows the mean cell residence time in the UAPBR obtained for the first 70 days of Phase II. There was considerable variation; initially the MCRT was >80 days which decreased to 30-40 days by 30th day of operation. The obtained MCRT was very high as compared to the hydraulic retention time (~8 hours) in the UAPBR. 120
100
MCRT (d)
80 60 40 20 0 0
10
20
30 40 Days of Phase II
50
60
Fig S1 Mean cell residence time in the UAPBR during Phase II
70
