scholarly journals Effect of Assisted Ultrasonication and Ozone Pretreatments on Sludge Characteristics and Yield of Biogas Production

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 743 ◽  
Author(s):  
Tuan Minh Le ◽  
Phong Thanh Vo ◽  
Tuan Anh Do ◽  
Lien Thi Tran ◽  
Hoa Thi Truong ◽  
...  

The effects of ultrasonic and ozonation pretreatments on organic solubilization, anaerobic biodegradability, and biogas production were elucidated in this study. Two pretreatment methods for batch anaerobic digestion for biogas recovery with the same material and experimental conditions were the focus for comparison. Anaerobic digestion experiments were conducted at ambient temperature with the solid retention time set to 25 days. The obtained results indicated that the soluble chemical oxygen demand increased from 0.344 without pretreatment to 1.023 and 1.228 g/L with ultrasound and ozone pretreatments, respectively, whereas the yields of biogas production in the 25 days increased by 32.3 and 52.9% via ultrasonic irradiation and ozonation relative to the control case, respectively. The biodegradability of the organic compounds of the samples for the cases of ultrasound, ozone pretreatments, and control achieved 55.9, 64.31, and 39.18%, respectively, in terms of chemical oxygen demand (COD) removal efficiencies. The physicochemical characteristics of sludge flocs were investigated via scanning with particle sizes, which were obviously affected by pretreatments of sonication and ozonation, resulting in finer particles than in the control case.

2013 ◽  
Vol 67 (9) ◽  
Author(s):  
Karina Michalska ◽  
Stanisław Ledakowicz

AbstractThis work studies the influence of the alkali pre-treatment of Sorghum Moench — a representative of energy crops used in biogas production. Solutions containing various concentrations of sodium hydroxide were used to achieve the highest degradation of lignocellulosic structures. The results obtained after chemical pre-treatment indicate that the use of NaOH leads to the removal of almost all lignin (over 99 % in the case of 5 mass % NaOH) from the biomass, which is a prerequisite for efficient anaerobic digestion. Several parameters, such as chemical oxygen demand, total organic carbon, total phenolic content, volatile fatty acids, and general nitrogen were determined in the hydrolysates thus obtained in order to define the most favourable conditions. The best results were obtained for the Sorghum treated with 5 mass % NaOH at 121°C for 30 min The hydrolysate thus achieved consisted of high total phenolic compounds concentration (ca. 4.7 g L−1) and chemical oxygen demand value (ca. 45 g L−1). Although single alkali hydrolysis causes total degradation of glucose, a combined chemical and enzymatic pre-treatment of Sorghum leads to the release of large amounts of this monosaccharide into the supernatant. This indicates that alkali pre-treatment does not lead to complete cellulose destruction. The high degradation of lignin structure in the first step of the pre-treatment rendered the remainder of the biomass available for enzymatic action. A comparison of the efficiency of biogas production from untreated Sorghum and Sorghum treated with the use of NaOH and enzymes shows that chemical hydrolysis improves the anaerobic digestion effectiveness and the combined pre-treatment could have great potential for methane generation.


2021 ◽  
Vol 2139 (1) ◽  
pp. 012009
Author(s):  
J M Sanchez-Beltrán ◽  
J C Acevedo-Páez ◽  
F Moreno Gamboa

Abstract The present research aims to evaluate the physicochemical variables involved in the anaerobic digestion process to produce methane from manure on an agricultural farm; the farm has 2 equines that generate 12 Kg of manure per day. A manure sample was collected, and the following physicochemical parameters were determined: total solids, volatile solids, chemical oxygen demand, and pH. A tubular household biodigester was then implemented, consisting mainly of a polyethylene geomembrane that stores the organic matter and in which anaerobic digestion takes place. The performance of the biodigester was determined by the removal of organic matter quantified by volatile solids and chemical oxygen demand in the biodigester influent and digestate, of which removal of 82% of volatile solids and 74% of chemical oxygen demand was achieved. The average biogas production was 0.5 m3/day, and its lower heating value was 26,000 kJ/m3. The pH level of the biodigester was within the range of 6-7, in order to keep the methanogenic bacteria active, in charge of carrying out physicochemical process that guarantees anaerobic digestion and thus, the production of biogas.


Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 539
Author(s):  
Hilario Flores-Mejia ◽  
Antonio Lara-Musule ◽  
Eliseo Hernández-Martínez ◽  
Ricardo Aguilar-López ◽  
Hector Puebla

Efficient monitoring is an open problem in the operation of anaerobic digestion processes, due to the lack of accurate, low-cost, and proper sensors for the on-line monitoring of key process variables. This paper presents two approaches for the indirect monitoring of the anaerobic digestion of cheese whey wastewater. First, the observability property is addressed using conventional and nonconventional techniques, including an observability index. Then, two model-based observer techniques, an extended Luenberger observer, a sliding mode observer, and a data-driven technique based on fractal analysis are formulated and discussed. The performance and capabilities of the proposed methodologies are illustrated on a validated model with experimental data of the anaerobic digestion of cheese whey. Experimental pH measurements are used for the data-driven approach based on fractal analysis. The experimental data sets correspond to experimental conditions (pH > 7.5 and temperature (T) = 40 °C) favoring volatile fatty acid (VFA) production (30 g/L) with simultaneously acceptable biogas production (3420 mL). Results also show that the proposed observers were able to predict satisfactory key process variables. On the other hand, the fractal analysis provides reliable qualitative trends of VFA production and chemical oxygen demand (COD) consumption.


2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Firda Mahira Alfiata Chusna ◽  
Melly Mellyanawaty ◽  
Estin Nofiyanti

The production of crude palm oil (CPO) in Indonesia tends to increase over time. Palm oil mill effluent (POME) is the wastewater generated from the palm oil mill process with high organic content. POME is a potential source for anaerobic digestion due to its high organic content. The challenge of POME treatment using an anaerobic process is to enhance biogas production with high soluble chemical oxygen demand (sCOD) removal efficiency. The purpose of this study was to evaluate the effect of selected trace elements addition onto zeolite as immobilization media to the anaerobic digestion of POME in a fluidized batch system. Natural zeolite was used as the medium to immobilize microorganisms in an anaerobic fluidized bed reactor (AFBR). This study used three trace elements impregnated to natural zeolites, i.e. Ni2+, Zn2+, Mg2+. The result shows that Ni2+ and Zn2+ improve the methanogenesis process, prevent the accumulation of VFA as an intermediate product and increase the methane (biogas) production. Meanwhile, Mg2+ only reduced sCOD significantly but it did not affect methane production. Fluidization enhanced the performance of the POME anaerobic digestion process. The fluidization provide a positive effect to enhance biogas production and sCOD removal. The efficiency of sCOD removal in the entire reactors were 80.82%; 81.77%; 75.89% for AFBR-Ni; AFBR-Zn and AFBR-control respectively. The total volume of methane produced by the three AFBR were 163,04; 136,42; 62,79 (in ml CH4 / g sCOD) for AFBR-Ni; AFBR-Zn and AFBR-control, respectively. A B S T R A KProduksi crude palm oil (CPO) di Indonesia cenderung meningkat seiring bertambahnya waktu. Palm oil mill effluent (POME) adalah air limbah yang dihasilkan dari proses penggilingan kelapa sawit dengan kandungan organik yang tinggi. Tantangan dalam mengolah POME menggunakan proses peruraian anaerobik adalah untuk meningkatkan produksi biogas dengan efisiensi penurunan soluble chemical oxygen demand (sCOD) yang tinggi. Tujuan dari penelitian ini adalah mengevaluasi pengaruh penambahan trace element terseleksi pada media imobilisasi zeolit terhadap proses peruraian anaerobik limbah POME dengan sistem batch terfluidisasi. Zeolit alam berperan sebagai media imobilisasi mikroorganisme dalam anaerobic fluidized bed reactor (AFBR). Penelitian ini menggunakan tiga trace element yang diimpregnasikan pada zeolit alam yaitu Ni2+, Zn2+, Mg2+. Hasil penelitian menunjukkan bahwa Ni2+ dan Zn2+ sebagai trace element dapat meningkatkan proses metanogenesis dan mencegah akumulasi VFA sebagai produk antara serta meningkatkan produksi gas metana (biogas). Mg2+ sebagai trace element menurunkan sCOD dengan cukup signifikan namun tidak diimbangi dengan banyaknya metana yang dihasilkan. Fluidisasi meningkatkan performa dari proses peruraian anaerobik POME. Proses fluidisasi memberi pengaruh positif dalam meningkatkan produksi biogas dan soluble chemical oxygen demand (sCOD) removal. Nilai sCOD removal yaitu 80,82%; 81,77%; 75,89% berturut-turut untuk AFBR-Ni; AFBR-Zn dan AFBR-kontrol. Total volume metana yang dihasilkan oleh ketiga AFBR yaitu 163,04; 136,42; 62,79 (dalam ml CH4 / g sCOD) berturut-turut untuk AFBR-Ni; AFBR-Zn dan AFBR-kontrol.


2018 ◽  
Vol 78 (8) ◽  
pp. 1772-1781 ◽  
Author(s):  
Hyungjun (Brian) Jo ◽  
Wayne Parker ◽  
Peiman Kianmehr

Abstract A range of thermal pretreatment conditions were used to evaluate the impact of high pressure thermal hydrolysis on the biodegradability of waste activated sludge (WAS) under aerobic and anaerobic conditions. It was found that pretreatment did not increase the overall extent to which WAS could be aerobically biodegraded. Thermal pretreatment transformed the biodegradable fraction of WAS (XH) to readily biodegradable chemical oxygen demand (COD) (SB) (16.5–34.6%) and slowly biodegradable COD (XB) (45.8–63.6%). The impact of pretreatment temperature and duration on WAS COD fractionation did not follow a consistent pattern as changes in COD solubilization did not correspond to the observed generation of SB through pretreatment. The pretreated WAS (PWAS) COD fractionations determined from aerobic respirometry were employed in anaerobic modeling and it was concluded that the aerobic and anaerobic biodegradability of PWAS differed. It was found that thermal pretreatment resulted in as much as 50% of the endogenous decay products becoming biodegradable in anaerobic digestion. Overall, it was concluded that the COD fractionation that was developed based upon the aerobic respirometry was valid. However, it was necessary to implement a first-order decay process that reflected changes in the anaerobic biodegradability of the endogenous products through pretreatment.


2017 ◽  
Vol 23 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Gamze Dalgic ◽  
Ilter Turkdogan ◽  
Kaan Yetilmezsoy ◽  
Emel Kocak

The study investigated the pretreatment of real paracetamol (PCT) wastewater of a pharmaceutical industry by Fenton process. At the best experimental conditions (COD/H2O2 = 1/1, Fe+2/H2O2 = 1/70, settling method:centrifuging, pH 6 at settling step), 92.7, 92.7, 95.5, 99.1, 99.9 and 99.4% of chemical oxygen demand (COD), total organic carbon (TOC), 5-day biological oxygen demand (BOD5), PCT, para-amino phenol (PAP) and aniline were removed, respectively. Changes in the concentrations of these parameters were also investigated for both oxidation and settling steps of Fenton process. It was found that COD and TOC were removed at the settling step (precipitation) whereas PCT, PAP and aniline were removed at the oxidation step. Mass balance calculations were also studied to show the mass distributions of COD in different phases (gas + foam, effluent and sludge). Fenton process was found as an effective method for the pretreatment of real PCT wastewater for discharging in a determined collective treatment plant.


2019 ◽  
Vol 10 (8) ◽  
pp. 1602
Author(s):  
Khansa Luqyana Hapsari ◽  
Firyal Tharifa ◽  
Setyo Sarwanto Moersidik ◽  
Sandyanto Adityosulindro ◽  
Cindy Rianti Priadi

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2392 ◽  
Author(s):  
Marcin Dębowski ◽  
Marcin Zieliński ◽  
Marta Kisielewska ◽  
Joanna Kazimierowicz

The aim of this study was the performance evaluation of anaerobic digestion of dairy wastewater in a multi-section horizontal flow reactor (HFAR) equipped with microwave and ultrasonic generators to stimulate biochemical processes. The effects of increasing organic loading rate (OLR) ranging from 1.0 g chemical oxygen demand (COD)/L·d to 4.0 g COD/L·d on treatment performance, biogas production, and percentage of methane yield were determined. The highest organic compounds removals (about 85% as COD and total organic carbon—TOC) were obtained at OLR of 1.0–2.0 g COD/L·d. The highest biogas yield of 0.33 ± 0.03 L/g COD removed and methane content in biogas of 68.1 ± 5.8% were recorded at OLR of 1.0 g COD/L·d, while at OLR of 2.0 g COD/L·d it was 0.31 ± 0.02 L/COD removed and 66.3 ± 5.7%, respectively. Increasing of the OLR led to a reduction in biogas productivity as well as a decrease in methane content in biogas. The best technological effects were recorded in series with an operating mode of ultrasonic generators of 2 min work/28 min break. More intensive sonication reduced the efficiency of anaerobic digestion of dairy wastewater as well as biogas production. A low nutrient removal efficiency was observed in all tested series of the experiment, which ranged from 2.04 ± 0.38 to 4.59 ± 0.68% for phosphorus and from 9.67 ± 3.36 to 20.36 ± 0.32% for nitrogen. The effects obtained in the study (referring to the efficiency of wastewater treatment, biogas production, as well as to the results of economic analysis) proved that the HFAR can be competitive to existing industrial technologies for food wastewater treatment.


2020 ◽  
Vol 12 (12) ◽  
pp. 5222 ◽  
Author(s):  
A. Sinan Akturk ◽  
Goksel N. Demirer

The positive effects of conductive material supplementation on anaerobic digestion have been mainly investigated for single synthetic substrates, while its significance for real and complex organic wastes such as food waste has not been sufficiently investigated. This study investigated the effect of conductive material (biochar and magnetite) and trace metal supplementation on the anaerobic digestion of food waste by means of biochemical methane potential assays. The results indicated that the supplementation of biochar and trace metals improved both total biogas production and methane yields. A biochar dose of 2.0 and 5.0 g/L resulted in 11.2 ± 6.5 and 27.3 ± 9.5% increase in biogas and 8.3 ± 6.8 and 33.2 ± 2.8% increase in methane yield, respectively. Moreover, the same reactors demonstrated high food waste stabilization performance of over 80% chemical oxygen demand removal efficiency. These results indicate that biochar supplementation leads to more enhanced anaerobic digestion operation that could be through increased surface area for microbial growth and/or direct interspecies electron transfer mechanism. In turn, food waste will not only be stabilized but also valorized by anaerobic digestion at higher efficiencies that support sustainable waste management through both environmentally safe disposal and value-added generation.


2012 ◽  
Vol 531 ◽  
pp. 528-531 ◽  
Author(s):  
Na Wei

Anaerobic digestion is an economic and environmentally friendly technology for treating the biomass material-sewage sludge, but has some limitations, such as the low efficient biogass production. In this paper ultrasound was proposed as pre-treatment for effective sludge anaerobic digestion. Sludge anaerobic digestion experiments with ultrasonic pretreatment was investigated. It can be seen that this treatment effectively leaded to the increase of soluble chemical oxygen demand(SCOD) and volatile fatty acids(VFA)concentration. High concentration of VFA leaded to a increase in biogas production. Besides, the SV of sludge was reduced and the settling characteristics of sludge was improved after ultrasonic pretreatment. It can be concluded that sludge anaerobic digestion with ultrasonic pretreatment is an effective method for biomass material transformation.


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