Enhancement of nitrate removal in synthetic groundwater using wheat rice stone

2012 ◽  
Vol 66 (9) ◽  
pp. 1900-1907 ◽  
Author(s):  
Siqi Hong ◽  
Jianmei Zhang ◽  
Chuanping Feng ◽  
Baogang Zhang ◽  
Puxi Ma
Keyword(s):  
Trace Elements ◽  
Activated Carbon ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Nitrate Removal ◽  
Oxygen Demand ◽  
Nitrite Accumulation ◽  
Synthetic Groundwater ◽  
Biofilm Carriers ◽  
Growth Of Bacteria

To enhance the efficiency of nitrate removal from synthetic groundwater, wheat rice stone (WRS) and granular activated carbon (GAC) were employed as biofilm carriers for denitrification under different HRT (hydraulic retention time) and C/N ratios. Four different ratios of GAC to WRS (0, 0.5, 1.0, and 2.0) were investigated to determine the most appropriate ratio of GAC and WRS. The NO3−-N, NO2−-N, COD levels and pH of the effluent were also investigated under various HRT and C/N ratios. The results showed that the column at a GAC/WRS ratio of 1.0 performed best under a C/N ratio of 0.9 and an HRT of 8 h, with 99% nitrate being removed. In addition, little nitrite accumulation and chemical oxygen demand (COD) were observed in effluent under these conditions. These results demonstrated that, with no addition of phosphor in the influent, the nitrate removal efficiency can be enhanced by WRS because WRS can leach trace elements and phosphor to promote the growth of bacteria.

Working Parameters Optimization of Hydrolysis-acidogenesis reactor in two stage anaerobic digestion of slaughterhouse Wastewater for Biogas Production

2020 ◽  
Author(s):  
Dejene Tsegaye Bedane ◽  
Mohammed Mazharuddin Khan ◽  
Seyoum Leta Asfaw
Keyword(s):  
Anaerobic Digestion ◽  
Working Conditions ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Slaughterhouse Wastewater ◽  
Working Parameters

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

scholarly journals Effect of hydraulic retention time on chemical oxygen demand and total nitrogen removal in intermittently aerated constructed wetlands

2020 ◽  
Vol 15 (3) ◽  
pp. 1 ◽  
Author(s):  
Isabela Pires da Silva ◽  
Gabriela Barbosa da Costa ◽  
João Gabriel Thomaz Queluz ◽  
Marcelo Loureiro Garcia
Keyword(s):  
Chemical Oxygen Demand ◽  
Constructed Wetlands ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Constructed Wetland ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Intermittent Aeration

   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.

scholarly journals Influence of a new ornamental species (Spathiphyllum blandum) on the removal of COD, nitrogen, phosphorus and fecal coliforms: a mesocosm wetland study with PET and tezontle substrates

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
Keyword(s):  
Developing Countries ◽  
New Species ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Fecal Coliforms ◽  
Contaminated Water ◽  
A New Species ◽  
Nitrogen Phosphorus ◽  
Ornamental Species

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.

scholarly journals Optimising the Hydraulic Retention Time in a Pilot-Scale Microbial Electrolysis Cell to Achieve High Volumetric Treatment Rates Using Concentrated Domestic Wastewater

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2945 ◽  
Author(s):  
Daniel D. Leicester ◽  
Jaime M. Amezaga ◽  
Andrew Moore ◽  
Elizabeth S. Heidrich
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Direct Analysis ◽  
Pilot Scale ◽  
Electrolysis Cell ◽  
Treatment Technique ◽  
Microbial Electrolysis Cell ◽  
Microbial Electrolysis

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.

POME Treatment Efficacy as Affected by Carrier Material Size in Micro-Bioreactor System

2014 ◽  
Vol 567 ◽  
pp. 104-109
Author(s):  
Wai Loan Liew ◽  
Khalida Muda ◽  
Mohd Azraai Kassim ◽  
Kok Yan Lai ◽  
Zi Yang Si ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Hydraulic Retention Time ◽  
Palm Kernel ◽  
Oxygen Demand ◽  
Quality Parameters ◽  
Palm Kernel Shell ◽  
Effluent Quality ◽  
Carrier Material ◽  
Bioreactor System ◽  
Palm Oil Mill

This paper presents the effect of different sizes of palm kernel shell (PKS) activated carbon as the carrier material in a micro-bioreactor system to treat the palm oil mill effluent (POME). Three different sizes of PKS activated carbon were used as the carrier material, i.e. 4.750 – 2.360 mm (large), 1.180 – 0.710 mm (average) and 0.425 – 0.300 mm (small). The systems were run for a total of 29 days under hydraulic retention time (HRT) of 24 hours. The performances of several effluent quality parameters of POME regarding the use of PKS activated carbon of different sizes were studied. PKS activated carbon with size 1.180 – 0.710 mm showed the highest removal performances for chemical oxygen demand (COD), ammoniacal-nitrogen (AN), and solids, with 41 %, 84.6 %, and 88 % of removal respectively. The system with PKS activated carbon of size 4.750 - 2.360 mm showed the highest performance in removing TP (45 %), while 1.180 – 0.710 mm size of PKS activated carbon showed the highest performance in removing TN (53 %). The system was also found to effectively reduce the effluent colour. In overall, the PKS activated carbon of size 1.180 – 0.710 mm showed the best results as a carrier material to be used in the micro-bioreactor system in treating POME compared to the other two sizes.

scholarly journals Efektivitas IPAL portabel sebagai alternatif pengelolaan limbah cair domestik

2019 ◽  
pp. 235-243
Author(s):  
Ika Bagus Priyambada ◽  
Purwono Purwono
Keyword(s):  
Chemical Oxygen Demand ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Oxygen Demand

Di Indonesia, selain sebagai saluran air alamiah, sungai sering pula digunakan sebagai tempat pembuangan air limbah kegiatan rumah tangga (domestik). Penggunaan teknologi yang efisien dan alami merupakan solusi sederhana dan murah untuk mengolah air limbah domestik dengan sistem desentralisasi. Tujuan penelitian ini adalah mengolah air limbah domestik menggunakan IPAL portabel dengan dimensi kecil, sehingga aplikatif untuk skala rumah tangga. Penelitian dilakukan di Laboratorium Lingkungan, Departemen Teknik Lingkungan, Universitas Diponegoro selama 3 bulan. Metode penelitian menggunakan IPAL portabel untuk mengolah air limbah domestik skala rumah tangga dengan sistem kontinu. Limbah domestik berasal dari kantin kampus Universitas Diponegoro. IPAL portabel menggunakan sistem kombinasi anaerob-aerob yang dilengkapi dengan bak penampung limbah awal, bak penangkap lemak dan bak efluen. Waktu tinggal hidrolis atau Hydraulic Retention Time (HRT) dilakukan pada 3 variasi yaitu 4 jam, 8 jam dan 12 jam. Hasil penelitian menunjukkan bahwa konsentrasi amoniak mengalami penurunan terbesar pada HRT 12 jam dengan efisiensi penyisihan sebesar 60%. Konsentrasi awal sebesar 40,99 mg/l turun menjadi 16,4 mg/l. Konsentrasi Chemical Oxygen Demand (COD) dan minyak & lemak juga mengalami penurunan terbesar pada HRT 12 jam, masing-masing turun sebesar 71% dan 91% dari konsentrasi awal. IPAL portabel ini paling efektif dalam menyisihkan minyak & lemak.

scholarly journals Dynamics of Archaeal and Bacterial Communities in Response to Variations of Hydraulic Retention Time in an Integrated Anaerobic Fluidized-Bed Membrane Bioreactor Treating Benzothiazole Wastewater

Archaea ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yue Li ◽  
Qi Hu ◽  
Da-Wen Gao
Keyword(s):  
Fluidized Bed ◽  
Removal Efficiency ◽  
Retention Time ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
High Strength ◽  
Service Period ◽  
Miseq Platform

An integrated anaerobic fluidized-bed membrane bioreactor (IAFMBR) was investigated to treat synthetic high-strength benzothiazole wastewater (50 mg/L) at a hydraulic retention time (HRT) of 24, 18, and 12 h. The chemical oxygen demand (COD) removal efficiency (from 93.6% to 90.9%), the methane percentage (from 70.9% to 69.27%), and the methane yield (from 0.309 m3 CH4/kg·CODremoved to 0.316 m3 CH4/kg·CODremoved) were not affected by decreasing HRTs. However, it had an adverse effect on membrane fouling (decreasing service period from 5.3 d to 3.2 d) and benzothiazole removal efficiency (reducing it from 97.5% to 82.3%). Three sludge samples that were collected on day 185, day 240, and day 297 were analyzed using an Illumina® MiSeq platform. It is striking that the dominant genus of archaea was always Methanosaeta despite of HRTs. The proportions of Methanosaeta were 80.6% (HRT 24), 91.9% (HRT 18), and 91.2% (HRT 12). The dominant bacterial genera were Clostridium in proportions of 23.9% (HRT 24), 16.4% (HRT 18), and 15.3% (HRT 12), respectively.

Treatment of Domestic Strength Wastewater with Anaerobic Hybrid Reactors

1987 ◽  
Vol 22 (3) ◽  
pp. 474-490 ◽  
Author(s):  
R.L. Droste ◽  
S.R. Guiot ◽  
S.S. Gorur ◽  
K.J. Kennedy
Keyword(s):  
Retention Time ◽  
Suspended Solids ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Anaerobic Treatment ◽  
Synthetic Wastewater ◽  
Solids Retention Time ◽  
Solids Retention ◽  
Removal Efficiencies ◽  
Hybrid Reactors

Abstract Anaerobic treatment of dilute synthetic wastewater (300-1,000 mg chemical oxygen demand/L using laboratory upflow sludge blanket filter reactors with and without effluent recycle is described. Treatment of dilute synthetic wastewater at hydraulic retention times less than 1 and 2 h in reactors without and with recycle, respectively, resulted in biomass washout as the solids retention time decreased to less than 12 d. Reseeding would be required to operate at these critical hydraulic retention times for extended periods. Treatment of dilute synthetic wastewater at hydraulic retention times between 3-12 h resulted in soluble COD removal efficiencies between 84-95% treating 300 mg COD/L. At a 3 h hydraulic retention time, solids retention time of 80 d and stable reactor biomass concentrations of 25 g volatile suspended solids/L were maintained.

Performance of Moving Bed Biofilm Reactor Treating Beverages Wastewater Using Cosmo Ball Coated With and Without Activated Carbon

2020 ◽  
Vol 17 (2) ◽  
pp. 700-703
Author(s):  
J. Nur Dhamirah Sakinah ◽  
M. I. Aida Isma
Keyword(s):  
Activated Carbon ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
Total Suspended Solid ◽  
Suspended Solid ◽  
Biofilm Reactor ◽  
Growth Media ◽  
High Concentration ◽  
Moving Bed ◽  
Carbon Absorption

Beverages industry producing large amount of wastewater during production and the cleaning process. The effluent discharge needs to be treated as it is harmful to the environment due to its high concentration of organic substances. In this study, the aim is to investigate the moving bed biofilm reactor’s performance in treating beverages wastewater with (CMBAC) and without activated carbon (CMB). The surface of cosmo ball was coated with granular activated carbon used as the attached growth media in the reactor. 18 L of MBBR using cosmo ball as media was setup at flowrate and hydraulic retention time of 1.5 L/hr and 8 hours, respectively. The reactor was maintained at pH 7 with minimum dissolved oxygen concentration of 2 mg/L. Experiment was repeated by using CMBAC as media. The best percentage removal achieved for chemical oxygen demand and total suspended solid was by MBBR using CMBAC with 92.7% and 83.4%, respectively. It should be noted that absorption of contaminant by activated carbon absorption enhanced the organic removal in the reactor.

Autotrophic denitrification of landfill leachate using elemental sulphur

1996 ◽  
Vol 34 (5-6) ◽  
pp. 469-476 ◽  
Author(s):  
A. Koenig ◽  
L. H. Liu
Keyword(s):  
Particle Size ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Nitrate Removal ◽  
Packed Bed ◽  
Elemental Sulphur ◽  
Limiting Factor ◽  
Autotrophic Denitrification ◽  
Sulphur Particle

One of the most economical means of nitrogen removal from leachate is biological treatment by nitrification, followed by heterotrophic denitrification. An alternative biological denitrification process is autotrophic denitrification using Thiobacillus denitrificans. This autotrophic bacteria oxidizes elemental sulphur to sulphate while reducing nitrate to elemental nitrogen gas, thereby eliminating the need for addition of organic carbon compounds. For this study, pilot-scale elemental sulphur packed bed columns with fixed-film denitrification have been selected as the most suitable treatment process. The effect of hydraulic retention time as well as the effect of concentration and loading rate of nitrate on nitrate removal efficiency as a function of sulphur particle size were determined. The results indicate that (i) autotrophic denitrification can effectively remove nitrate from synthetic and actual nitrified leachate at concentrations much higher than hitherto reported; (ii) the minimum hydraulic retention time necessary for complete denitrification depends on sulphur particle size; (iii) the maximum area loading rate, in g NO3−-N/m2·d, appears to be the process limiting factor and is practically independent of sulphur particle size; and (iv) the observed stoichiometric relationships compare well with those previously reported.

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