scholarly journals Effect of Variation in Co-Digestion Ratios of Matooke, Cassava and Sweet Potato Peels on Hydraulic Retention Time, Methane Yield and Its Kinetics

2016 ◽  
Vol 06 (04) ◽  
pp. 93-115 ◽  
Author(s):  
Peter Tumutegyereize ◽  
Clever Ketlogetswe ◽  
Jerekias Gandure ◽  
Noble Banadda
Keyword(s):  
Sweet Potato ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Methane Yield ◽  
Potato Peels

Effect of hydraulic retention time on pretreatment of blended municipal sludge

2011 ◽  
Vol 64 (4) ◽  
pp. 967-973
Author(s):  
S. Koyunluoglu-Aynur ◽  
R. Riffat ◽  
S. Murthy
Keyword(s):  
Retention Time ◽  
Volatile Fatty Acids ◽  
Hydraulic Retention Time ◽  
Operating Conditions ◽  
Methane Yield ◽  
Municipal Sludge ◽  
Volatile Solids ◽  
Significant Difference ◽  
Autothermal Thermophilic Aerobic Digestion ◽  
Pretreatment Processes

The objective of the present work was to evaluate the effect of hydraulic retention time (HRT) on hydrolysis and acidogenesis for the pretreatment processes: acid phase digestion (APD) and autothermal thermophilic aerobic digestion (ATAD) using blended municipal sludge. The effect of the different pretreatment steps on mesophilic anaerobic digestion (MAD) was evaluated in terms of methane yield, keeping the operating conditions of the MAD the same for all systems. Best operating conditions for both APD and ATAD were observed for 2.5 d HRT with high total volatile fatty acids (tVFA), and the highest methane yield observed for MAD. No significant difference was observed between the two processes in terms of overall volatile solids (VS) reduction with same total HRT. The autothermal process produced heat of 14,300 J/g VS removed from hydrolytic and acetogenic reactions without compromising overall methane yields when the HRT was 2.5 d or lower and the total O2 used was 0.10 m3 O2/g VS added or lower. However, the process needs the input of oxygen and engineering analysis should balance these differences when considering the relative merits of the two pretreatment processes. This is the first study of its kind directly comparing these two viable pretreatment processes with the same sludge.

scholarly journals Strategies to Optimize Microalgae Conversion to Biogas: Co-Digestion, Pretreatment and Hydraulic Retention Time

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2096 ◽  
Author(s):  
Maria Solé-Bundó ◽  
Humbert Salvadó ◽  
Fabiana Passos ◽  
Marianna Garfí ◽  
Ivet Ferrer
Keyword(s):  
Retention Time ◽  
Cell Walls ◽  
Hydraulic Retention Time ◽  
Microscopic Analysis ◽  
Fold Increase ◽  
Resistant Cell ◽  
Methane Yield ◽  
Thermal Pretreatment ◽  
Primary Sludge ◽  
Yield Increase

This study aims at optimizing the anaerobic digestion (AD) of biomass in microalgal-based wastewater treatment systems. It comprises the co-digestion of microalgae with primary sludge, the thermal pretreatment (75 °C for 10 h) of microalgae and the role of the hydraulic retention time (HRT) in anaerobic digesters. Initially, a batch test comparing different microalgae (untreated and pretreated) and primary sludge proportions showed how the co-digestion improved the AD kinetics. The highest methane yield was observed by adding 75% of primary sludge to pretreated microalgae (339 mL CH4/g VS). This condition was then investigated in mesophilic lab-scale reactors. The average methane yield was 0.46 L CH4/g VS, which represented a 2.9-fold increase compared to pretreated microalgae mono-digestion. Conversely, microalgae showed a low methane yield despite the thermal pretreatment (0.16 L CH4/g VS). Indeed, microscopic analysis confirmed the presence of microalgae species with resistant cell walls (i.e., Stigioclonium sp. and diatoms). In order to improve their anaerobic biodegradability, the HRT was increased from 20 to 30 days, which led to a 50% methane yield increase. Overall, microalgae AD was substantially improved by the co-digestion with primary sludge, even without pretreatment, and increasing the HRT enhanced the AD of microalgae with resistant cell walls.

scholarly journals Kinerja Upflow Anaerobic Fixed Bed Reactor dengan Media Penunjang Batu Apung dalam Penyisihan Organik dan Pembentukan Biogas dari Biowaste Fase Cair

2015 ◽  
Vol 10 (4) ◽  
pp. 148 ◽  
Author(s):  
Prismita Nursetyowati ◽  
Prayatni Soewondo ◽  
Marisa Handajani
Keyword(s):  
Retention Time ◽  
Hydraulic Retention Time ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Methane Yield

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.

Surface interaction of sweet potato peels (Ipomoea batata) with Cd(II) and Pb(II) ions in aqueous medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Aqueous Medium ◽  
Sweet Potato ◽  
Adsorption Process ◽  
Low Cost ◽  
Correlation Coefficients ◽  
Order Kinetic ◽  
Thermodynamic Evaluation ◽  
Dissociative Mechanism ◽  
Pseudo Second Order ◽  
Potato Peels

The removal of Cd(II) and Pb(II) ions from aqueous medium was studied using potato peels biomass. The adsorption process was evaluated using Atomic Absorption Spectrophotometer (AAS). The Vibrational band of the potato peels was studied using Fourier Transform Infrared Spectroscopy (FTIR). The adsorption process was carried out with respect to concentration, time, pH, particle size and the thermodynamic evaluation of the process was carried at temperatures of 30, 40, 50 and 60(0C), respectively. The FTIR studies revealed that the potato peels was composed of –OH, -NH, –C=N, –C=C and –C-O-C functional groups. The optimum removal was obtained at pH 8 and contact time of 20 min. The adsorption process followed Freundlich adsorption and pseudo second-order kinetic models with correlation coefficients (R2) greater than 0.900. The equilibrium adsorption capacity showed that Pb(II) ion was more adsorbed on the surface of the potato peels biomass versus Cd (II) ion (200.91 mg/g > 125.00 mg/g). The thermodynamic studies indicated endothermic, dissociative mechanism and spontaneous adsorption process. This study shows that sweet potato peels is useful as a low-cost adsorbent for the removal of Cd(II) and Pb(II) ions from aqueous medium.

The nitrogen removal potential of predenitrification systems in sensitive coastal areas

1995 ◽  
Vol 32 (7) ◽  
pp. 135-142
Author(s):  
E. Görgün ◽  
N. Artan ◽  
D. Orhon ◽  
R. Tasli
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Retention Time ◽  
Treatment Process ◽  
Hydraulic Retention Time ◽  
Domestic Sewage ◽  
Coastal Areas ◽  
Careful Evaluation ◽  
Denitrification Kinetics

Effective nitrogen removal is now required to protect water quality in sensitive coastal areas. This involves a much more difficult treatment process than for conventional domestic sewage as wastewater quantity and quality exhibits severe fluctuations in touristic zones. Activated sludge is currently the most widely used wastewater treatment and may be upgraded as a predenitrification system for nitrogen removal. Interpretation of nitrification and denitrification kinetics reveal a number of useful correlations between significant parameters such as sludge age, C/N ratio, hydraulic retention time, total influent COD. Nitrogen removal potential of predenitrification may be optimized by careful evaluation of wastewater character and the kinetic correlations.

Evaluation of a tropical single-cell waste stabilization pond system for irrigation

1995 ◽  
Vol 31 (12) ◽  
pp. 267-273 ◽  
Author(s):  
B. S. O. Ceballos ◽  
A. Konig ◽  
B. Lomans ◽  
A. B. Athayde ◽  
H. W. Pearson
Keyword(s):  
Single Cell ◽  
Removal Efficiency ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Full Scale ◽  
Waste Stabilization Pond ◽  
North East ◽  
Helminth Eggs ◽  
Waste Stabilization ◽  
Better Than

A single full-scale primary facultative pond in Sapé, north-east Brazil was monitored for performance and efficiency. The pond had a hydraulic retention time of 61 days and achieved a 95% BOD5 removal efficiency and had no helminth eggs in the effluent. The effluent failed to meet the WHO faecal coliform guideline for unrestricted irrigation. The pond was dominated by the cyanobacterium Microcystis and gave better than predicted orthophosphate removal. Details of how the system could be simply upgraded utilizing the same land are discussed.

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