Elucidating the Kinetics of Ammonia Inhibition to Anaerobic Digestion Through Extended Batch Experiments and Stimulation-Inhibition Modeling

Swine manure mono-digestion results in relatively low methane productivity due to the low degradation rate of its solid fraction (manure fibers), and due to the high ammonia and water content. The aqueous ammonia soaking (AAS) pretreatment of manure fibers has been proposed for overcoming these limitations. In this study, continuous anaerobic digestion (AD) of manure mixed with optimally AAS-treated manure fibers was compared to the AD of manure mixed with untreated manure fibers. Due to lab-scale pumping restrictions, the ratio of AAS-optimally treated manure fibers to manure was only 1/3 on a total solids (TS) basis. However, the biogas productivity and methane yield were improved by 17% and 38%, respectively, also confirming the predictions from a simplified 1st order hydrolysis model based on batch experiments. Furthermore, an improved reduction efficiency of major organic components was observed for the digester processing AAS-treated manure fibers compared to the non-treated one (e.g., 42% increased reduction for cellulose fraction). A preliminary techno-economic analysis of the proposed process showed that mixing raw manure with AAS manure fibers in large-scale digesters could result in a 72% increase of revenue compared to the AD of manure mixed with untreated fibers and 135% increase compared to that of solely manure.

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Kinetics of combined hydrothermal pretreatment and anaerobic digestion of lignocellulosic biomass (pepper plant and eggplant)

Environmental Technology ◽

10.1080/09593330.2021.1976283 ◽

2021 ◽

pp. 1-37

Author(s):

K. Hamraoui ◽

J.A. Siles ◽

A.F. Chica ◽

M.A. Martín ◽

H. El Bari

Keyword(s):

Anaerobic Digestion ◽

Lignocellulosic Biomass ◽

Hydrothermal Pretreatment ◽

Pepper Plant ◽

Kinetics Of

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Final products and kinetics of biochemical and chemical sulfide oxidation under microaerobic conditions

Water Science & Technology ◽

10.2166/wst.2018.485 ◽

2018 ◽

Vol 78 (9) ◽

pp. 1916-1924 ◽

Cited By ~ 3

Author(s):

Lucie Pokorna-Krayzelova ◽

Dana Vejmelková ◽

Lara Selan ◽

Pavel Jenicek ◽

Eveline I. P. Volcke ◽

...

Keyword(s):

Mathematical Model ◽

Oxidation Rate ◽

Elemental Sulfur ◽

Sulfide Oxidation ◽

Cost Effective ◽

Anaerobic Treatment ◽

Batch Experiments ◽

Cost Effective Method ◽

Microaerobic Conditions ◽

Kinetics Of

Abstract Hydrogen sulfide is a toxic and usually undesirable by-product of the anaerobic treatment of sulfate-containing wastewater. It can be removed through microaeration, a simple and cost-effective method involving the application of oxygen-limiting conditions (i.e., dissolved oxygen below 0.1 mg L−1). However, the exact transformation pathways of sulfide under microaerobic conditions are still unclear. In this paper, batch experiments were performed to study biochemical and chemical sulfide oxidation under microaerobic conditions. The biochemical experiments were conducted using a strain of Sulfuricurvum kujiense. Under microaerobic conditions, the biochemical sulfide oxidation rate (in mg S L−1 d−1) was approximately 2.5 times faster than the chemical sulfide oxidation rate. Elemental sulfur was the major end-product of both biochemical and chemical sulfide oxidation. During biochemical sulfide oxidation elemental sulfur was in the form of white flakes, while during chemical sulfide oxidation elemental sulfur created a white suspension. Moreover, a mathematical model describing biochemical and chemical sulfide oxidation was developed and calibrated by the experimental results.

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Effects of thermochemical pretreatment on the anaerobic digestion of waste activated sludge

Water Science & Technology ◽

10.2166/wst.1997.0315 ◽

1997 ◽

Vol 35 (8) ◽

pp. 209-215 ◽

Cited By ~ 77

Author(s):

Shuzo Tanaka ◽

Toshio Kobayashi ◽

Ken-ichi Kamiyama ◽

Ma. Lolita N. Signey Bildan

Keyword(s):

Anaerobic Digestion ◽

Activated Sludge ◽

Production Rate ◽

Methane Production ◽

Waste Activated Sludge ◽

Batch Experiments ◽

Industrial Wastewaters ◽

Thermochemical Pretreatment ◽

Chemical Heating ◽

Methane Production Rate

Effects of pretreatment on the anaerobic digestion of waste activated sludge (WAS) were investigated in terms of VSS solubilization and methane production by batch experiments. The methods of pretreatment studied are NaOH addition (chemical), heating (thermal) and heating with NaOH addition (thermochemical) to the domestic WAS and to the combined WAS from domestic, commercial and industrial wastewaters. The thermochemical pretreatment gave the best result among three methods in the combined WAS, i.e., the VSS was solubilized by 40-50% and the methane production increased by more than 200% over the control when the WAS was heated at 130°C for 5 minutes with the dose 0.3 g NaOH/g VSS. In the domestic WAS, the VSS solubilization rate was 70-80% but the increase of the methane production was about 30% after thermochemically pretreated. The domestic WAS consists of 41% protein, 25% lipid and 14% carbohydrate on COD basis, and the solubilization rate of protein, which is the largest constituent of the WAS, was 63% in the thermochemical pretreatment. Although the effect of the thermochemical pretreatment on the methane production was higher to the combined WAS than to the domestic WAS, the methane production rate was 21.9 ml CH4/g VSSWAS·day in the domestic WAS and 12.8 ml CH4/g VSSWAS·day in the combined WAS.

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Anaerobic Digestion Characteristics for Sewage Sludge and Organic Wastes by Batch Experiments

Journal of Japan Society of Civil Engineers Ser G (Environmental Research) ◽

10.2208/jscejer.69.iii_605 ◽

2013 ◽

Vol 69 (7) ◽

pp. III_605-III_614

Author(s):

Taira HIDAKA ◽

Feng WANG ◽

Tsutomu UCHIDA ◽

Yutaka SUZUKI

Keyword(s):

Anaerobic Digestion ◽

Sewage Sludge ◽

Organic Wastes ◽

Batch Experiments

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Kinetics of Anaerobic Digestion of Dairy Fat Waste with Saponification Pre-Treatment

Jurnal Rekayasa Proses ◽

10.22146/jrekpros.48959 ◽

2019 ◽

Vol 13 (2) ◽

pp. 112 ◽

Cited By ~ 1

Author(s):

Rifki Wahyu Kurnianto ◽

Wiratni Budhijanto ◽

Rochim Bakti Cahyono

Keyword(s):

Anaerobic Digestion ◽

Lipid Content ◽

Alternative Energy ◽

Organic Waste ◽

High Lipid Content ◽

Dairy Fat ◽

High Lipid ◽

Pre Treatment ◽

Kinetics Of ◽

Floating Layer

Anaerobic digestion has been an attractive field of research in the era of energy crisis. Biogas, which is the product of anaerobic digestion, provides alternative energy, while at the same time it also prevents pollution due to organic waste accumulation. Among various organic wastes, dairy fat waste is a potential substrate for anaerobic digestion. Fat waste has high theoretical biogas potential because of its high lipid content. However, anaerobic digestion of organic waste with high lipid content is quite challenging. The main obstacle in anaerobic digestion of fat waste is its tendency to form insoluble floating layer on top of the liquid phase. This phenomenon hinders the access of hydrolytic bacteria to the substrate. Saponification is one of the methods to increase the solubility of the floating layer and hence to improve the availability of substrate for the bacteria. Saponification changes the lipid content into soap which has both polar and non-polar functional groups and the polar side will increase the solubility of the substrate in water. This study evaluated the effect of different dosage of base added as the reactant during saponification pre-treatment on the productivity of anaerobic digestion of dairy fat waste. The kinetics of the anaerobic digestion process was analyzed by mean of mathematical model. The variations of the alkaline dosages studied for saponification pre-treatment were 0.04 mol base/g sCOD; 0.02 mol base/g sCOD; and no pre-treatment for control reactor. This study proved that saponification increased the solubility of dairy fat waste. This result was confirmed by the hydrolysis constant value (kH) of 0.00782/day for reactor with saponification, which was twenty times of magnitude higher than the kH value of 0.00032/day in the reactor without saponification. However, the exposure to high pH during the saponification pre-treatment might somewhat inhibit indigenous acidogenic bacteria in the waste which results in lower methane yield in the reactors with saponification to be compared to the control reactor. A B S T R A KPeruraian anaerobik merupakan salah satu bidang riset yang sangat menarik perhatian dalam era krisis energi. Biogas tidak hanya menyediakan energi alternatif, tetapi juga dapat mencegah pencemaran akibat limbah organik. Limbah lemak susu adalah substrat yang potensial untuk proses peruraian anaerobik karena memiliki potensi biogas teoritis yang tinggi akibat kandungan lemaknya yang tinggi. Namun, peruraian anaerobik dari limbah organik dengan kandungan lemak yang tinggi memiliki tantangan tersendiri. Hambatan utama dalam peruraian anaerobik dari limbah lemak susu adalah kecenderungan untuk membentuk lapisan padatan yang tidak larut dan mengapung di bagian atas fase cair. Fenomena ini menghambat akses bakteri hidrolisis terhadap substrat. Saponifikasi adalah salah satu cara untuk meningkatkan kelarutan lapisan padatan tersebut, sehingga meningkatkan ketersediaan substrat untuk bakteri. Saponifikasi akan mengubah kandungan lemak menjadi sabun yang memiliki gugus fungsi polar maupun non-polar. Gugus fungsi yang bersifat polar akan meningkatkan kelarutan substrat dalam air. Studi ini mengevaluasi pengaruh dari berbagai dosis larutan basa yang ditambahkan sebagai reaktan selama perlakuan awal saponifikasi terhadap peruraian anaerobik limbah lemak susu. Kinetika proses peruraian anaerobik dianalisis dengan menggunakan model matematika. Variasi dosis yang diamati pengaruhnya untuk perlakuan awal saponifikasi adalah 0,04 mol basa/g sCOD; 0,02 mol basa/g sCOD; dan nol (tanpa perlakuan awal saponifikasi). Dari penelitian ini, terbukti bahwa saponifikasi berhasil meningkatkan kelarutan limbah lemak susu dan juga ditunjukkan oleh nilai konstanta hidrolisis (kH) 0,00782/hari lebih tinggi dua puluh kali lipat dibandingkan dengan nilai kH 0,00032/hari pada reaktor tanpa saponifikasi. Akan tetapi, penelitian ini juga mengindikasikan bahwa bakteri asidogenik bawaan substrat terhambat kinerjanya oleh paparan pH yang tinggi selama perlakuan awal saponifikasi berlangsung sehingga hasil gas metan yang diperoleh lebih rendah daripada reaktor kontrol.

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