scholarly journals EFFECTS OF ORGANIC LOADING RATE AND HYDRAULIC RETENTION TIME ON TREATMENT OF PHENOLIC WASTEWATER IN AN ANAEROBIC IMMOBILIZED FLUIDIZED BED REACTOR

2014 ◽  
Vol 22 (1) ◽  
pp. 40-49 ◽  
Author(s):  
Roya Pishgar ◽  
Ghasem D. Najafpour ◽  
Bahram Navayi Neya ◽  
Zeinab Bakhshi ◽  
Nafise Mousavi
Keyword(s):  
Fluidized Bed ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Fluidized Bed Reactor ◽  
Phenol Concentration ◽  
Total Alkalinity ◽  
Organic Loading ◽  
Phenolic Wastewater ◽  
Removal Efficiencies

Treatability of phenolic wastewater in an anaerobic immobilized fluidized bed reactor (AIFBR) in consequence of stepwise increment in phenolic load as well as decrease in hydraulic retention time (HRT) was investigated. The experimental data indicated that high degradation efficiencies of phenol and COD in the bioreactor at low HRTs and high organic loading rates were obtained. At constant HRT of 16 h with increase in influent phenol concentration from 98 to 630 mg/l, the average phenol and COD removals were 96 and 88%, respectively. However, further increase in phenol concentration in the feed stream to 995 mg/l resulted in decrease in phenol and COD removal efficiencies to 84 and 79%, respectively. For influent phenol concentration of 995 mg/l, the biogas production rate of 4.55 l/l.d was obtained. As HRT decreased from 3 to 0.15 day, the system showed high stability; influent phenol and COD were removed and reached to average values of 17 and 173 mg/l correspond to the removal efficiencies of about 97 and 90.5%, respectively. The bioreactor experienced a failure with further decrease in HRT to 0.1 day. Biogas production was gradually decreased from 7.04 l/l.d at HRT of 3 days to 2.23 l/l.d at HRT of 0.1 days. The value of the ratio of volatile fatty acids to total alkalinity (VFAs/TA) ranged from 0.03 to 0.24 during the entire course of operation.

Optimization of Hydraulic Retention Time and Organic Loading Rate in Anaerobic Digestion of Squeezed Pineapple Liquid Wastes for Biogas Production

2021 ◽  
Author(s):  
Napisa Pattharaprachayakul ◽  
Narumon Kesonlam ◽  
Pongpitak Duangjumpa ◽  
Vilai Rungsardthong ◽  
Worakrit Suvajittanont ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Biogas Production ◽  
Solid Wastes ◽  
Organic Loading Rate ◽  
Hybrid Reactor ◽  
Organic Loading ◽  
Liquid Wastes

Pineapple wastes are produced in huge amount during the industrial canning process of pineapple; in Thailand over 400,000 tons per annum of canned pineapple exported leaving behind the waste. Besides the pulps and peels as solid wastes, the squeezed pineapple liquid wastes (SPLW) extracted from solid wastes can also be used for anaerobic digestion. In the present study, the anaerobic digestion of liquid squeezed from industrial pineapple peels was carried out using a lab-scale hybrid reactor. The reactor was operated for over 170 days with the hydraulic retention time (HRT) of 20 days decreasing down to 5 days and simultaneous control of organic loading rate (OLR). Under controlled conditions in the hybrid reactor, pH was maintained at 6.5–7.6 by adding alkaline for anaerobic microbial activity. Results showed that the chemical oxygen demand (COD) removal efficiency was at ≥ 90% for all conditions. The biogas production (mL/day) increased thoroughly from longer HRT to shorter HRT, as same as methane production with the maximum values (HRT 5 days, OLR 5 g/COD/ day with recirculation) of 55,130 and 30,322 mL/day, respectively. Moreover, the highest yields of biogas and methane were also investigated under similar conditions with the values of 0.504 and 0.277 L/gCOD, respectively. Interestingly, this optimization of both HRT and OLR of lab-scale anaerobic digestion process could be further practically applied to pilot or industrial scale in canned pineapple factories for biogas production.

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