scholarly journals Studies on Effect of Change in Temperature and Hydraulic Retention Time on Physical and Kinetic Parameters on Degradation of Synthetic Phenolic Waste Water in Single Stage Attached Film Fixed Bed Reactor

2015 ◽  
Vol 22 (1) ◽  
Author(s):  
Mishu Singh

The treatment of toxic and inhibitory phenolic compounds using biological techniques have been pursued vas a promising and widely accepted treatment process due to its easiness of handling, a greater level of stabilization of waste and properly operated to prevent the production of secondary pollutants. Up-flow Anaerobic Bio-Reactors (UAFB) has been widely applied for the handling of high organic load industrial wastewater. The treatment of synthetic phenolic wastewater by a single stage anaerobic fixed bed bioreactor with granite stones packing at four different temperatures was studied. The effect of hydraulic retention time on COD reduction and other steady state characteristics and kinetic parameters, which form these characteristics, was also studied. A recirculated single stage up-flow anaerobic bioreactor operated at all the above-given temperatures with initial BOD 1462 mg/l and initial COD 5720 mg/l for a digestion period of 25 days with a working volume of 1000 ml. The performance of the reactor was monitored after every five days and analyzed in terms of percentage (COD, BOD, TS, TDS, VS removal and biogas production). The removal efficiency of BOD, COD, TS, TDS and VS reached a maximum value of 63.20%, 61.24%, 44.88%, 47.67% and 53.12% respectively. With the change in HRT, the maximum COD reduction was 66.04% at 24 hrs HRT at 400C with initial COD of 5000 mg/l. Specific biogas yield increased up to 0.0162 ml/mg CODr.   Keywords— Phenol, anaerobic, fixed bed bioreactor, wastewater, up-flow anaerobic sludge blanket, experimental design, IndiaAbbreviations: BOD -Biochemical Oxygen Demand, COD - Chemical Oxygen Demand,   TDS  - Total Dissolved Solids,  VS - Volatile Solids, UAFB - Up-Flow Anaerobic Fixed Bed Bioreactor

2017 ◽  
Vol 39 (4) ◽  
pp. 469 ◽  
Author(s):  
Daiane Cristina de Freitas ◽  
Fernando Hermes Passig ◽  
Cristiane Kreutz ◽  
Karina Querne de Carvalho ◽  
Eudes José Arantes ◽  
...  

The study of the hydrodynamic behavior in reactors provides characteristics of the flow regime and its anomalies that can reduce biological processes efficiency due to the decrease of the useful volume and the hydraulic retention time required for the performance of microbial activity. In this study, the hydrodynamic behavior of an anaerobic-aerobic fixed bed reactor, operated with HRT (hydraulic retention time) of 24, 18 and 12 hours, was evaluated in the treatment of raw cattle slaughterhouse wastewater. Polyurethane foam and expanded clay were used as support media for biomass immobilization. Experimental data of pulse type stimulus-response assays were performed with eosin Y and bromophenol blue, and adjusted to the single-parameter theoretical models of dispersion and N-continuous stirred tank reactors in series (N-CSTR). N-CSTR model presented the best adjustment for the HRT and tracers evaluated. RDT (residence time distribution) curves obtained with N-CSTR model in the assays with bromophenol blue resulted in better adjustment compared to the eosin Y. The predominant flow regime in AAFBR (anaerobic aerobic fixed bed reactor) is the N-CSTR in series, as well as the existence of preferential paths and hydraulic short-circuiting. 


2015 ◽  
Vol 10 (4) ◽  
pp. 148 ◽  
Author(s):  
Prismita Nursetyowati ◽  
Prayatni Soewondo ◽  
Marisa Handajani

Dalam penelitian ini, biowaste yang digunakan adalah sampah pasar. Sampah pasar menyumbang sekitar 12% dari berat total sampah kota. Upflow Anaerobic Fixed Bed Reactor (UAFB-R) yang digunakan dalam penelitian ini memakai media penunjang batu apung dengan resirkulasi efluen dan tanpa pengatur pH. Penelitian ini bertujuan untuk melihat kinerja UAFB-R dengan media penunjang batu apung dalam penyisihan organik dan pembentukan biogas terutama gas metan biowaste fasa cair. Hydraulic Retention Time UAFB-R ditentukan sebesar 6 hari dengan volume operasi sebesar 9 liter. Variasi beban organik influen dalam penelitian adalah ± 0,32 kg COD/m3.hari, ± 0,64 kg COD/m3.hari, ± 0,96 kg COD/m3.hari, ± 1,28 kg COD/m3.hari, ± 1,6 kg COD/m3.hari, dan ± 1,92 kg COD/m3.hari. Pada rentang beban organik influen ± 0,32 kg COD/m3.hari sampai ± 1,92 kg COD/m3.hari di kondisi tunak, semakin besar beban organik influen maka efisiensi penyisihan COD semakin kecil dan rasio TAV/Alkalinitas semakin besar. Namun, semakin kecil beban organik influen maka komposisi dan volume gas metan serta methane yield cenderung semakin besar. Saat variasi beban influen ± 0,96 kg COD/m3.hari dihasilkan volume gas metan terbesar sebanyak 1,77 liter, sedangkan saat variasi beban organik influen ± 0,64 kg COD/m3.hari dicapai komposisi gas metan dan methane yield terbesar sebesar 77,4% dan 0,249. Selain itu, semakin tinggi konsentrasi sulfat maka maka volume biogas yang terbentuk menjadi lebih kecil.


2020 ◽  
Author(s):  
Dejene Tsegaye Bedane ◽  
Mohammed Mazharuddin Khan ◽  
Seyoum Leta Asfaw

Abstract Background : Wastewater from agro-industries such as slaughterhouse is typical organic wastewater with high value of biochemical oxygen demand, chemical oxygen demand, biological organic nutrients (Nitrogen and phosphate) which are insoluble, slowly biodegradable solids, pathogenic and non-pathogenic bacteria and viruses, parasite eggs. Moreover it contains high protein and putrefies fast leading to environmental pollution problem. This indicates that slaughterhouses are among the most environmental polluting agro-industries. Anaerobic digestion is a sequence of metabolic steps involving consortiums of several microbial populations to form a complex metabolic interaction network resulting in the conversation of organic matter into methane (CH 4 ), carbon dioxide (CO 2 ) and other trace compounds. Separation of the phase permits the optimization of the organic loading rate and HRT based on the requirements of the microbial consortiums of each phase. The purpose of this study was to optimize the working conditions for the hydrolytic - acidogenic stage in two step/phase anaerobic digestion of slaughterhouse wastewater. The setup of the laboratory scale reactor was established at Center for Environmental Science, College of Natural Science with a total volume of 40 liter (36 liter working volume and 4 liter gas space). The working parameters for hydrolytic - acidogenic stage were optimized for six hydraulic retention time 1-6 days and equivalent organic loading rate of 5366.43 – 894.41 mg COD/L day to evaluate the effect of the working parameters on the performance of hydrolytic – acidogenic reactor. Result : The finding revealed that hydraulic retention time of 3 day with organic loading rate of 1,788.81 mg COD/L day was a as an optimal working conditions for the parameters under study for the hydrolytic - acidogenic stage. The degree of hydrolysis and acidification were mainly influenced by lower hydraulic retention time (higher organic loading rate) and highest values recorded were 63.92 % at hydraulic retention time of 3 day and 53.26% at hydraulic retention time of 2 day respectively. Conclusion : The finding of the present study indicated that at steady state the concentration of soluble chemical oxygen demand and total volatile fatty acids increase as hydraulic retention time decreased or organic loading rate increased from 1 day hydraulic retention time to 3 day hydraulic retention time and decreases as hydraulic retention time increase from 4 to 6 day. The lowest concentration of NH 4 + -N and highest degree of acidification was also achieved at hydraulic retention time of 3 day. Therefore, it can be concluded that hydraulic retention time of 3 day/organic loading rate of 1,788.81 mg COD/L .day was selected as an optimal working condition for the high performance and stability during the two stage anaerobic digestion of slaughterhouse wastewater for the hydrolytic-acidogenic stage under mesophilic temperature range selected (37.5℃). Keywords : Slaughterhouse Wastewater, Hydrolytic – Acidogenic, Two Phase Anaerobic Digestion, Optimal Condition, Agro-processing wastewater


2019 ◽  
Vol 63 (1) ◽  
pp. 86-95 ◽  
Author(s):  
YiKun Geng ◽  
ZhengHao Li ◽  
Li Yuan ◽  
XinRong Pan ◽  
GuoPing Sheng

Author(s):  
Isabela Pires da Silva ◽  
Gabriela Barbosa da Costa ◽  
João Gabriel Thomaz Queluz ◽  
Marcelo Loureiro Garcia

   This study evaluated the effect of hydraulic retention time on chemical oxygen demand (COD) and total nitrogen (TN) removal in an intermittently aerated constructed wetlands. Two horizontal subsurface-flow constructed wetlands were used: one without aeration and the other aerated intermittently (1 hour with aeration/7 hours without aeration). Both systems were evaluated treating domestic wastewater produced synthetically. The flow rate into the two CWs was 8.6 L day-1 having a hydraulic retention time of 3 days. The results show that the intermittently aerated constructed wetland were highly efficient in removing COD (98.25%), TN (83.60%) and total phosphorus (78.10%), while the non-aerated constructed wetland showed lower efficiencies in the removal of COD (93.89%), TN (48.60%) and total phosphorus (58.66). These results indicate, therefore, that intermittent aeration allows the simultaneous occurrence of nitrification and denitrification processes, improving the removal of TN in horizontal subsurface-flow constructed wetlands. In addition, the use of intermittent aeration also improves the performance of constructed wetlands in removing COD and total phosphorus.


2020 ◽  
Vol 81 (5) ◽  
pp. 961-970 ◽  
Author(s):  
Luis Sandoval ◽  
Florentina Zurita ◽  
Oscar Andrés Del Ángel-Coronel ◽  
Jacel Adame-García ◽  
José Luis Marín-Muñíz

Abstract The objective of this study was to evaluate the influence of a new species of plant (Spathiphyllum blandum) in the elimination of chemical oxygen demand (COD), nitrogen, phosphorus and fecal coliforms (FCs) in mesocosms of wetlands with polyethylene terephthalate (PET) and tezontle substrates under a tropical climate. The experiments were developed at the mesocosm level in 20 experimental units; 10 were planted with Spathiphyllum blandum, five in PET substrates and five in tezontle, and 10 more were used as controls without vegetation, of which five contained tezontle and five contained PET. The systems were fed with contaminated water from the river Sordo, with a hydraulic retention time of 3 days for 12 months; samples were taken in the influent and effluents of the mesocosms every 2 weeks, with the purpose of evaluating the removal of contaminants. The results showed that presence of this species tended to improve or significantly improved the removal of COD, NH4-N, PO4-P, and FCs by 7%, 16%, 29% and 12%, respectively. It was also possible to confirm that the presence of this species reduced the rate of denitrification. These results confirm that in developing countries it is feasible to find new wetland species to be used for wastewater phytoremediation.


Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2945 ◽  
Author(s):  
Daniel D. Leicester ◽  
Jaime M. Amezaga ◽  
Andrew Moore ◽  
Elizabeth S. Heidrich

Bioelectrochemical systems (BES) have the potential to deliver energy-neutral wastewater treatment. Pilot-scale tests have proven that they can operate at low temperatures with real wastewaters. However, volumetric treatment rates (VTRs) have been low, reducing the ability for this technology to compete with activated sludge (AS). This paper describes a pilot-scale microbial electrolysis cell (MEC) operated in continuous flow for 6 months. The reactor was fed return sludge liquor, the concentrated filtrate of anaerobic digestion sludge that has a high chemical oxygen demand (COD). The use of a wastewater with increased soluble organics, along with optimisation of the hydraulic retention time (HRT), resulted in the highest VTR achieved by a pilot-scale MEC treating real wastewater. Peak HRT was 0.5-days, resulting in an average VTR of 3.82 kgCOD/m3∙day and a 55% COD removal efficiency. Finally, using the data obtained, a direct analysis of the potential savings from the reduced loading on AS was then made. Theoretical calculation of the required tank size, with the estimated costs and savings, indicates that the use of an MEC as a return sludge liquor pre-treatment technique could result in an industrially viable system.


2016 ◽  
Vol 74 (8) ◽  
pp. 1992-1998 ◽  
Author(s):  
Mehrdad Farrokhi ◽  
Mostafa Mahdavianpour ◽  
Mehdi Shirzad-Siboni ◽  
Mohammad Naimi-Joubani ◽  
Hamzeh Ali Jamali

Variation in hospital wastewater (HWW) pollutants and differences with municipal wastewater (MWW), make the use of biokinetic coefficients obtained from activated sludge in the MWW treatment unprofitable for designing, modeling and evaluation of biological processes for HWW treatment. Since this study was conducted to evaluate the performance and biokinetic coefficients of a fixed bed bioreactor (FBBR) using rice husks as fixed media in HWW treatment, a new modified method was also proposed for biokinetic estimation in FBBR processes. For these purposes, five hydraulic retention times along with five sludge retention times were introduced to a pilot setup and the required data were attained. The performance process for chemical oxygen demand (COD) removal was significant (87.8–97.5%) in different conditions. The values of biokinetic coefficients k, Ks, Y and Kd were obtained as 2.42 (day−1), 55.5 (mgCOD/L), 0.2929 (mgBiomass/mgCOD) and 0.0164 (day−1), respectively. The rice husks with high surface area and high affinity for biomass accumulation on its surface are promising media for a green and environmentally friendly FBBR process. The kinetics parameters values are utilizable for modeling of FBBR using rice husks as fixed media in HWW treatment.


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