scholarly journals Dolomitic limestone as an alkalizing agent for treating cassava starch wastewater in an anaerobic reactor

Revista CERES ◽  
2018 ◽  
Vol 65 (5) ◽  
pp. 388-394
Author(s):  
Denise Palma ◽  
Julia Piechontcoski Fernandes ◽  
Marney Pascoli Cereda ◽  
Simone Damasceno Gomes
Keyword(s):  
Oxygen Demand ◽  
Cassava Starch ◽  
Total Alkalinity ◽  
Dolomitic Limestone ◽  
Organic Loading ◽  
Reactor Operation ◽  
Anaerobic Reactor ◽  
Loading Rates ◽  
Volatile Acidity ◽  
Starch Wastewater

ABSTRACT Cassava processing wastewater has a low Volatile Acidity/Total Alkalinity ratio, low buffering capacity and became quickly acidified. In this trial, dolomitic limestone was used as an alkalizing agent in an anaerobic reactor to treat cassava starch wastewater. The dolomitic limestone contained 27% CaO and 23% MgO and granulometry between 24.5 and 38.1 mm. The average Chemical Oxygen Demand of the wastewater was 13331.30 mgO2 L-1, the organic loading rates (OLR) ranged from 1.23 to 16.43 gCOD L-1 d-1 and the hydraulic retention times ranged from 10.00 to 0.80 days. The results showed that the calcium concentrations increased in the reactor effluent and the magnesium concentrations decreased as the organic loading rates increased. Ca2+ and Mg2+ concentrations were approximately 5,000 and 5.05 times greater in the sludge than in the inoculum, respectively. The average pH, Total alcalinity, Volatile Acidity and Volatile Acidity/ Total alcalinity values were 6.69, 882.54 mgCaCO3 L-1, 221.55 mgCH3COOH L-1 and 0.22, respectively. The loss of limestone mass corresponded to only 2.51% of the initial mass, after 134 days of anaerobic reactor operation. Finally, it was concluded that the limestone effectively controlled acidification through the alkalinity increased in the system.

Anaerobic co-digestion of winery waste and waste activated sludge: assessment of process feasibility

2013 ◽  
Vol 69 (2) ◽  
pp. 269-277 ◽  
Author(s):  
C. Da Ros ◽  
C. Cavinato ◽  
F. Cecchi ◽  
D. Bolzonella
Keyword(s):  
Activated Sludge ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Waste Activated Sludge ◽  
Organic Loading ◽  
Operational Conditions ◽  
Loading Rates ◽  
Thermophilic Conditions ◽  
Soluble Chemical Oxygen Demand

In this study the anaerobic co-digestion of wine lees together with waste activated sludge in mesophilic and thermophilic conditions was tested at pilot scale. Three organic loading rates (OLRs 2.8, 3.3 and 4.5 kgCOD/m3d) and hydraulic retention times (HRTs 21, 19 and 16 days) were applied to the reactors, in order to evaluate the best operational conditions for the maximization of the biogas yields. The addition of lee to sludge determined a higher biogas production: the best yield obtained was 0.40 Nm3biogas/kgCODfed. Because of the high presence of soluble chemical oxygen demand (COD) and polyphenols in wine lees, the best results in terms of yields and process stability were obtained when applying the lowest of the three organic loading rates tested together with mesophilic conditions.

scholarly journals Performance of Anaerobic Digestion of Acidified Palm Oil Mill Effluent under Various Organic Loading Rates and Temperatures

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2432
Author(s):  
Muhammad Arif Fikri Hamzah ◽  
Peer Mohamed Abdul ◽  
Safa Senan Mahmod ◽  
Azratul Madihah Azahar ◽  
Jamaliah Md. Jahim
Keyword(s):  
Anaerobic Digestion ◽  
Palm Oil ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Oxygen Demand ◽  
Microbial Community Analysis ◽  
Palm Oil Mill Effluent ◽  
Methane Formation ◽  
Organic Loading ◽  
Loading Rates ◽  
Palm Oil Mill

This study compared the performance of thermophilic and mesophilic digesters of an anaerobic digestion system from palm oil mill effluent (POME), in which temperature is a key parameter that can greatly affect the performance of anaerobic digestion. The digesters were incubated at two distinct temperatures of 55 and 37 °C, and operated with varying organic loading rates (OLRs) of 2.4, 3.2, and 4.0 g COD/L.d by altering the chemical oxygen demand (COD) of acidified POME during feeding. The results indicated that the performance of anaerobic digestion increased as the OLR increased from 2.4 to 4.0 g COD/L.d. At the OLR of 4.0 g COD/L.d, the thermophilic condition showed the highest methane yield of 0.31 ± 0.01 L/g COD, accompanied by the highest COD removal and volatile solid reduction, which were found to be higher than the mesophilic condition. Microbial community analysis via denaturing gradient gel electrophoresis (DGGE) revealed that Methanothermobacter sp. emerges as the dominant microbe, which is known to utilize the carbon dioxide pathway with hydrogen acting as an electron donor for methane formation

scholarly journals Performance of Modified Anaerobic Hybrid Baffled (MAHB) bioreactor treating recycled paper mill effluent: Effects of organic loading rates

2021 ◽  
Vol 6 (1) ◽  
pp. 15-18
Author(s):  
Siti Roshayu Hassan ◽  
Irvan Dahlan
Keyword(s):  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Paper Mill ◽  
Organic Loading ◽  
Recycled Paper ◽  
Paper Mill Effluent ◽  
Loading Rates ◽  
Bioreactor System ◽  
Maximum Removal

The performance of modified anaerobic hybrid baffled (MAHB) bioreactor treating recycled paper mill effluent (RPME) was investigated at various organic loading rates (OLR) of 1, 2, 3 and 4 g COD/ L.day. The bioreactor was operated continuously at constant hydraulic retention time (HRT) of a day without effluent recycled and chemicals adjustment/addition. Throughout 70 days of operation, a maximum removal efficiency up to 97% of chemical oxygen demand (COD) and 98% of volatile fatty acid, biogas production of 12.51 L/day equivalent to methane (CH4) yield of 0.108L CH4/ g COD and a stable pH system between 6.6 to 7.2 were achieved. Additionally, alkalinity of the bioreactor system shows a stable profile that indicates the whole system was well buffered with a quit high degradation of volatile solid (VS) up to 18%. These results indicated that MAHB bioreactor has been successfully treated RPME at various OLR.

Application of combined membrane biological reactor and electro-oxidation processes for the treatment of landfill leachates

2009 ◽  
Vol 60 (3) ◽  
pp. 605-614 ◽  
Author(s):  
Fathi Aloui ◽  
Firas Fki ◽  
Slim Loukil ◽  
Sami Sayadi
Keyword(s):  
Membrane Bioreactor ◽  
Biological Process ◽  
Ph Value ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Optimum Conditions ◽  
Organic Loading ◽  
Landfill Leachates ◽  
Loading Rates ◽  
Electro Oxidation

Landfill leachate (LFL) is a very complex wastewater that poses considerable hazards to local communities and the environment. With this concern in mind, the present study was undertaken to investigate the performance of an aerobic membrane bioreactor treating raw LFL from Djebel Chekir (Tunisia) discharge. The LFL samples collected from this site were found to be highly loaded with organic matter, ammonia, salts, greases, phenols and hydrocarbons. Important removals of chemical oxygen demand (COD) and NH4+-N were attained after 44 days of treatment at optimum conditions for the membrane and with organic loading rates (OLR) of 1.9 and 2.7 grams COD per litter and day. This treatment allowed for an important detoxification of the landfill leachates and a significant elimination of the microorganisms. Electrochemical oxidation using Pi/Ti was applied as a post-treatment and after the biological process in order to reduce the residual ammonia and COD. At a pH value of 9, current density of 4 A dm−2 and electrolysis time of 60 minutes, COD and ammonia nitrogen were reduced to 1,000 mg L−1 and 27 mg L−1, respectively. COD and NH4+-N removals were accompanied by significant detoxification.

Treatment of agricultural drainage water via downflow hanging sponge system for reuse in agriculture

2013 ◽  
Vol 13 (2) ◽  
pp. 403-412 ◽  
Author(s):  
Amr Fleifle ◽  
Ahmed Tawfik ◽  
Oliver C. Saavedra ◽  
Mohamed Elzeir
Keyword(s):  
Suspended Solids ◽  
Oxygen Demand ◽  
Drainage Water ◽  
Treated Wastewater ◽  
Agricultural Drainage ◽  
Organic Loading ◽  
Effluent Quality ◽  
Loading Rates ◽  
Agricultural Drainage Water ◽  
Negative Effect

Treatment of agricultural drainage water (ADW) in a down-flow hanging sponge (DHS) reactor has been investigated for a period of 1 y. The reactor was operated at different hydraulic retention times (HRTs) of 5.26, 2.63, and 1.5 h and corresponding organic loading rates (OLRs) of 2.01, 1.86, and 4.43 kg COD/m3 d, respectively. The results obtained indicated that, decreasing the HRT from 5.26 to 1.5 h negatively affected the chemical oxygen demand (COD) removal. Average COD percentage removal values dropped from 89.3 ± 5.4 to 72.2 ± 16% respectively. Total suspended solids (TSS) concentrations were reduced by 85.5 ± 8.3, 90.4 ± 2.1, and 91.4 ± 4.9 at HRTs of 5.26, 2.63, and 1.5 h, respectively. However, the nitrification efficiency was slightly decreased from 85.2 ± 17.4 to 82 ± 11.4% by decreasing the HRT from 5.26 to 1.5 h and increasing the OLR from 2.01 to 4.43 kg COD/m3 d, respectively. Likewise, reducing the HRT from 5.26 to 1.5 h exerted a slight negative effect on the removal of the total phosphorus (TP). Based on these results it is recommended to operate such a system at a HRT of 2.63 h and OLR not exceeding 2.0 kg COD/m3 d for providing an effluent quality complying with the standards regulating the use of treated wastewater for agricultural purposes.

Anaerobic digestion of waste biomass from the production of L-cystine in suspended-growth bioreactors

2015 ◽  
Vol 72 (4) ◽  
pp. 585-592
Author(s):  
Juan José Chávez-Fuentes ◽  
Miroslav Hutňan ◽  
Igor Bodík ◽  
Ronald Zakhar ◽  
Marianna Czölderová
Keyword(s):  
Hydrogen Sulfide ◽  
Ferrous Iron ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Waste Biomass ◽  
Organic Loading ◽  
Inhibitory Effects ◽  
Loading Rates ◽  
Anaerobic Bioreactors ◽  
Suspended Growth

Waste biomass from the industrial production of the amino acid L-cystine contains above-average concentrations of organic pollutants and significant concentrations of nitrogen and sulfur. The specific biogas production (SBP) of waste biomass was monitored in parallel suspended-growth laboratory anaerobic bioreactors. After severe inhibition was observed, three different procedures were applied to inhibited reactor sludge to counter-attack the inhibitory effects of sulfides, respectively hydrogen sulfide: micro-aeration, dilution with water and precipitation by ferrous iron cations. The performance of bioreactors was weekly monitored. Organic loading rates (as chemical oxygen demand, COD) ranged from 1.07 to 1.97 g L−1 d−1. At the end of the experimentation, SBP averaged 217, 300 and 320 l kg−1 COD with a methane content of 21%, 52% and 54%; specific sludge production averaged 133, 111 and 400 g total solids kg−1 COD, and inhibition was 49%, 27% and 25%; for the applied procedures of micro-aeration, dilution and precipitation respectively.

scholarly journals Comparison of thermophilic and mesophilic anaerobic treatment for potato processing wastewater using a contact reactor

2017 ◽  
Vol 19 (2) ◽  
pp. 318-326 ◽  
Keyword(s):  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Gas Production ◽  
Organic Loading ◽  
Potato Processing ◽  
Loading Rates ◽  
Methane Gas ◽  
Acid Ratio ◽  
Mesophilic Conditions ◽  
Better Than

In this study, different organic loading rates (OLRs) ranging from 1.1 to 5.0 kg COD/m3·day were used to assess the performance of an anaerobic reactor at the optimum mesophilic (35°C) and thermophilic (55°C) temperatures. The methane gas production rate of the thermophilic treatment was higher than that of the mesophilic treatment. The efficiency of chemical oxygen demand (COD) removal was observed to range from 89.12 to 93.20% following the thermophilic anaerobic treatment and from 76.36 to 92.62% following the mesophilic treatment. The average VFA (volatile fatty acid)/alkalinity ratio of the effluent was 0.3 under both thermophilic and mesophilic conditions for all the OLR applications. The HPr/HAc (propionic acid/acetic acid) ratio was calculated as 0.16 and 1.3 for the mesophilic and thermophilic treatments, respectively. For the mesophilic treatment, the average methane gas production was found to be 0.394 m3 CH4/kg CODremoved while it was 0.42 m3 CH4/kg CODremoved for the thermophilic experiment. However, the sludge settleability of the mesophilic treatment was better than that of the thermophilic treatment.

scholarly journals Performance evaluation of anaerobic baffled reactor (ABR) for treating alkali-decrement wastewater of polyester fabrics at incremental organic loading rates

2018 ◽  
Vol 77 (10) ◽  
pp. 2445-2453 ◽  
Author(s):  
Bo Yang ◽  
Hui Xu ◽  
Junfeng Wang ◽  
Dengming Yan ◽  
Qijun Zhong ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Longitudinal Distribution ◽  
Stable Operation ◽  
Organic Loading ◽  
Polyester Fabrics ◽  
Anaerobic Baffled Reactor ◽  
Operational Conditions ◽  
Loading Rates ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential

Abstract In this study, an anaerobic baffled reactor (ABR) with four compartments was employed to treat alkali-decrement wastewater of polyester fabrics under different organic loading rates. The stable operation of this reactor was achieved in 70 days at a hydraulic retention time of 36 h and mesophilic temperature of 35 ± 1 °C. It is found that the chemical oxygen demand removal and decolorization of this system can be as high as 79.0% and 87.7%, respectively. The different acidogenesis and methanogenesis in four compartments was acclimated by the variation of pH, oxidation reduction potential values and operational conditions in the spatial distribution of the first to fourth compartments of the ABR system. In addition, the dehydrogenase activity (DHA) and coenzyme F420 concentrations along the four compartments ranged from 67.8 to 185.21 μgTF/(gVSS·h) (TF: triphenyl formazan; VSS: volatile suspended solids) and 0.123 to 0.411 μmol/g, respectively. These results indicated that the ABR could separate acidogenesis and methanogenesis in longitudinal distribution and treat well the alkali-decrement wastewater.

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