scholarly journals Kinetic study and optimization of total solids for anaerobic digestion of kitchen waste: Bangladesh perspective

2021 ◽  
Author(s):  
Thamina Nasrin ◽  
Chayan Kumer Saha ◽  
Rajesh Nandi ◽  
Md. Sanaul Huda ◽  
Md. Monjurul Alam
Keyword(s):  
Anaerobic Digestion ◽  
Logistic Model ◽  
Research Work ◽  
Gas Production ◽  
Rural Environment ◽  
Kitchen Waste ◽  
Total Solids ◽  
Before And After ◽  
Methane Potential ◽  
Set Up

Abstract Kitchen waste from hotels and homes is one of the major problems for urban and rural environment and could be one of the best sources of renewable energy by producing biogas through anaerobic digestion. A research work was undertaken to assess the methane potential of kitchen waste at different total solids (TS) content. Kitchen wastes such as spoiled rice, brinjal, potato, papaya, tomato, fish and poultry parts etc., which are easily decomposed were selected for this study. Batch experiments were set up under ambient temperature. Kitchen waste was added in the batch digester at different TS content (5, 7, 10, 12 and 15%) and sealed for 146 days until the gas production stopped. Substrate characteristics were analyzed before and after the anaerobic digestion. The highest methane yield was 78.12 L/kg VS at 15% TS content followed by 12, 10, 7 and 5%. Different kinetic parameters were determined using logistic model and the model showed a good fit with the experimental results. After modelling using Minitab®, the optimum TS content for kitchen waste was found to be 14.90%.

Highly Efficient Anaerobic Digestion with Thermal Pretreatment

1985 ◽  
Vol 17 (4-5) ◽  
pp. 529-539 ◽  
Author(s):  
M. Hiraoka ◽  
N. Takeda ◽  
S. Sakai ◽  
A. Yasuda
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Pilot Plant ◽  
Molecular Size ◽  
Gas Production ◽  
Thermal Pretreatment ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Before And After ◽  
Pilot Plant Study

The effectiveness of an anaerobic digestion process with thermal pretreatment at a comparatively low temperature was examined. The waste activated sludge was thermally pretreated in the process. A laboratory scale experiment and a pilot plant study were conducted. Changes in volatile acids concentration, in major constituents of sludge and in molecular size distribution were examined before and after thermal pretreatment and anaerobic digestion. Thermal pretreatment resulted in an increase of more than 30 percent in digestion gas production. The major substrates decomposed were fats in the pilot plant study. Glyceride fatty acids are decomposed with thermal pretreatment and produce volatile acids such as acetic and propionic acids. The volatile acids are directly utilized by anaerobes to produce methane. Organic matter such as fats and carbohydrates are depolymerized with thermal pretreatment and produce soluble intermediate compounds such as higher fatty acids. The intermediates are utilized in the anaerobic digestion process. These two major effects facilitate the methane production process.

scholarly journals Leaching characteristics of poultry litter in first phase of multistage anaerobic digestion

2014 ◽  
Vol 3 (2) ◽  
pp. 76-82 ◽  
Author(s):  
Surya P Sunkavalli ◽  
A Gangagni Rao ◽  
P Swapnalata ◽  
M Zaheer
Keyword(s):  
Anaerobic Digestion ◽  
Poultry Litter ◽  
Organic Content ◽  
Total Solids ◽  
Batch Type ◽  
Solids Concentration ◽  
Inverse Effect ◽  
Leaching Experiments ◽  
Set Up ◽  
Leachate Quality

Poultry litter is highly biodegradable in nature. Therefore, it could be subjected to biomethanation to produce valuable biogas and bio-manure as byproducts. Some studies have been conducted along these lines in India by utilizing the poultry litter as a substrate in batch type dung digesters of KVIC and DENABANDHU models. However, these reactors have the drawbacks of high residence time (30 – 35 days), scum formation problems etc. Moreover, these batch type plants are not suitable for the treatment of large quantities of solid waste. Multistage anaerobic digestion has the potential to overcome some of the aforesaid issues. Anaerobic leaching experiments were conducted at different total solids concentration and pH using poultry litter in order to evaluate the leachate quality for a period of 7 days. The increase in Total solids (TS) % from 15 to 20% show inverse effect on VFA and Alkalinity. The change in pH from 8.5 to 5.5 didn’t show much impact on VFA but there is a small impact on alkalinity. It was also observed that the leaching of the organic matter in the solid to the liquid phase is very fast and it is taking place approximately in three to four days and subsequently leachate getting saturated. Therefore, reactor set up was made in the last phase to regularly remove the water from the reactor so that higher driving force is available for leaching. The study resulted in leaching of maximum organic content in the solid to liquid within three days. DOI: http://dx.doi.org/10.3126/ije.v3i2.10516 International Journal of the Environment Vol.3(2) 2014: 76-82

Effect of micro-oxygen pretreatment on gas production characteristics of anaerobic digestion of kitchen waste

2020 ◽  
Vol 22 (6) ◽  
pp. 1852-1858 ◽  
Author(s):  
Xiaofei Zhen ◽  
Xiaoyan Zhang ◽  
Shuaibing Li ◽  
Mingche Li ◽  
Jian Kang
Keyword(s):  
Anaerobic Digestion ◽  
Gas Production ◽  
Kitchen Waste ◽  
Production Characteristics

scholarly journals Prototype of a Biogas Anaerobic Digester from the Hostel Mess Kitchen Wastes

2019 ◽  
Vol 5 (2) ◽  
pp. 35-39
Author(s):  
Shivam Modi ◽  
Pooja Mahajan
Keyword(s):  
Solid Waste ◽  
Food Waste ◽  
Organic Waste ◽  
New Technologies ◽  
Anaerobic Fermentation ◽  
Energy Content ◽  
Research Work ◽  
Gas Production ◽  
Kitchen Waste ◽  
Biodegradable Waste

Biogas is a non-exhaustible of energy which can be formed from anaerobic fermentation of different types of biodegradable waste such as food waste, plant waste, animal waste sewage and other organic waste. The typical composition of Biogas includes CH4 (50–70%) which is responsible for maximum energy content along with CO2 (25–50%) that can be collected, stored and supplied. Biogas acts as a multipurpose and an eco- friendly sustainable resource of energy which can be utilized for cooking, electricity generation, lightning, heating etc. Biodegradable waste specifically produced in large amounts as a kitchen waste. In modern society, the solid waste per capita has been consistently increasing as of increase in population and change in socio-economic-cultural habits. The biogas production through the kitchen waste thereof provides a solution of disposal of solid waste. The bio gas production through anaerobic degradation pathways can be controlled and enhanced with the help of certain microorganisms and advancements of new technologies. In this research work, an attempt is being made to produce the biogas from kitchen and food waste collected from hostel mess of Chitkara University, Punjab and a novel method of production of microorganism has been also proposed for fast degradation of waste. Under this project, a survey for the estimation of daily production of organic waste from hostel mess has also been done for fifteen day. 

scholarly journals Anaerobic Codigestion of Food Waste and Polylactic Acid: Effect of Pretreatment on Methane Yield and Solid Reduction

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Shakira R. Hobbs ◽  
Prathap Parameswaran ◽  
Barbara Astmann ◽  
Jay P. Devkota ◽  
Amy E. Landis
Keyword(s):  
Anaerobic Digestion ◽  
Polylactic Acid ◽  
Food Waste ◽  
Alkaline Treatment ◽  
Alkaline Pretreatment ◽  
Digested Sludge ◽  
Acid Effect ◽  
Anaerobic Codigestion ◽  
Methane Potential ◽  
Set Up

Food waste and biopolymers, plastics derived from plants, are unexploited sources of energy when discarded in landfills without energy recovery. In addition, polylactic acid (PLA) and food waste have complimentary characteristics for anaerobic digestion; both are organic and degrade under anaerobic conditions. Lab-scale reactors were set up to quantify the solubilization of pretreated amorphous and crystalline PLA. Biochemical methane potential (BMP) assays were performed to quantify CH4 production from both treated and untreated PLA in the presence of food waste and anaerobic digested sludge. Amorphous and crystalline PLA reached near-complete solubilization at 97% and 99%, respectively, when alkaline pretreatment was applied. The PLA that received alkaline treatment produced the most of CH4 throughout the run time of 70 days. The PLA without treatment resulted in 54% weight reduction after anaerobic digestion. Results from this study show that alkaline pretreatment has the greatest solid reduction of PLA and maximum production of CH4 when combined with food waste and anaerobic digested sludge.

scholarly journals Application of the Initial Rate Method in Anaerobic Digestion of Kitchen Waste

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Lei Feng ◽  
Yuan Gao ◽  
Wei Kou ◽  
Xianming Lang ◽  
Yiwei Liu ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Initial Rate ◽  
Anaerobic Fermentation ◽  
Gas Production ◽  
Kitchen Waste ◽  
First Order ◽  
Hydrolysis Constants ◽  
Reaction Orders ◽  
Rate Method ◽  
Kinetics Of

This article proposes a methane production approach through sequenced anaerobic digestion of kitchen waste, determines the hydrolysis constants and reaction orders at both low total solid (TS) concentrations and high TS concentrations using the initial rate method, and examines the population growth model and first-order hydrolysis model. The findings indicate that the first-order hydrolysis model better reflects the kinetic process of gas production. During the experiment, all the influential factors of anaerobic fermentation retained their optimal values. The hydrolysis constants and reaction orders at low TS concentrations are then employed to demonstrate that the first-order gas production model can describe the kinetics of the gas production process. At low TS concentrations, the hydrolysis constants and reaction orders demonstrated opposite trends, with both stabilizing after 24 days at 0.99 and 1.1252, respectively. At high TS concentrations, the hydrolysis constants and the reaction orders stabilized at 0.98 (after 18 days) and 0.3507 (after 14 days), respectively. Given sufficient reaction time, the hydrolysis involved in anaerobic fermentation of kitchen waste can be regarded as a first-order reaction in terms of reaction kinetics. This study serves as a good reference for future studies regarding the kinetics of anaerobic digestion of kitchen waste.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Gasification as an optimum alternative for the sludge management

2011 ◽  
Vol 6 (4) ◽  
Author(s):  
C. Peregrina ◽  
J. M. Audic ◽  
P. Dauthuille
Keyword(s):  
Power Generation ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Combined Heat And Power ◽  
Gas Production ◽  
Waste Reduction ◽  
Fluidised Bed ◽  
Sludge Management ◽  
Gas Cleaning ◽  
Cleaning System

Assimilate sludge to a fuel is not new. Sludge incineration and Combined Heat and Power (CHP) engines powered with sludge-derived anaerobic digestion gas (ADG) are operations widely used. However, they have a room of improvement to reach simultaneously a positive net power generation and a significant level of waste reduction and stabilization. Gasification has been used in other realms for the conversion of any negative-value carbon-based materials, that would otherwise be disposed as waste, to a gaseous product with a usable heating value for power generation . In fact, the produced gas, the so-called synthetic gas (or syngas), could be suitable for combined heat and power motors. Within this framework gasification could be seen as an optimum alternative for the sludge management that would allow the highest waste reduction yield (similar to incineration) with a high power generation. Although gasification remains a promising route for sewage sludge valorisation, campaigns of measurements show that is not a simple operation and there are still several technical issues to resolve before that gasification was considered to be fully applied in the sludge management. Fluidised bed was chosen by certain technology developers because it is an easy and well known process for solid combustion, and very suitable for non-conventional fuels. However, our tests showed a poor reliable process for gasification of sludge giving a low quality gas production with a significant amount of tars to be treated. The cleaning system that was proposed shows a very limited removal performance and difficulties to be operated. Within the sizes of more common WWTP, an alternative solution to the fluidised bed reactor would be the downdraft bed gasifier that was also audited. Most relevant data of this audit suggest that the technology is more adapted to the idea of sludge gasification presented in the beginning of this paper where a maximum waste reduction is achieved with a great electricity generation thanks to the use of a “good” quality syngas in a CHP engine. Audit show also that there is still some work to do in order to push sludge gasification to a more industrial stage. Regardless what solution would be preferred, the resulting gasification system would involve a more complex scenario compared to Anaerobic Digestion and Incineration, characterised by a thermal dryer and gasifier with a complete gas cleaning system. At the end, economics, reliability and mass and energy yields should be carefully analysed in order to set the place that gasification would play in the forthcoming processing of sewage sludge.

A Mathematical Model for the Anaerobic Digestion Process Applied to a Mixture of Night Soil and Septic Tank Sludge

1986 ◽  
Vol 18 (7-8) ◽  
pp. 239-248 ◽  
Author(s):  
Sung Ryong Ha ◽  
Dwang Ho Lee ◽  
Sang Eun Lee
Keyword(s):  
Mathematical Model ◽  
Anaerobic Digestion ◽  
Biomass Concentration ◽  
Gas Production ◽  
Septic Tank ◽  
Volatile Acid ◽  
Hydraulic Residence Time ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Proposed Model

Laboratory scale experiments were conducted to develop a mathematical model for the anaerobic digestion of a mixture of night soil and septic tank sludge. The optimum mixing ratio by volume between night soil and septic tank sludge was found to be 7:3. Due to the high solids content in the influent waste, mixed-liquor volatile suspended solids (MLVSS) was not considered to be a proper parameter for biomass concentration, therefore, the active biomass concentration was estimated based on deoxyribonucleic acid (DNA) concentration in the reactor. The weight ratio between acidogenic bacteria and methanogenic bacteria in the mixed culture of a well-operated anaerobic digester was approximately 3:2. The proposed model indicates that the amount of volatile acid produced and the gas production rate can be expressed as a function of hydraulic residence time (HRT). The kinetic constants of the two phases of the anaerobic digestion process were determined, and a computer was used to simulate results using the proposed model for the various operating parameters, such as BOD5 and volatile acid concentrations in effluent, biomass concentrations and gas production rates. These were consistent with the experimental data.

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