scholarly journals Effect of Thermo-Chemical Pretreatment of Kenyan Market Waste on Mesophillic Biogas Production

Author(s):  
Kamau J. M ◽  
Mbui D. N ◽  
Mwaniki J. M ◽  
Waswa G. A.

Effects of pretreatment on the anaerobic digestion of waste fruit and vegetable market waste were investigated in biogas production by batch experiments. The pretreatment was NaOH and HCl thermochemical, thermal and chemical methods. The wastes were chopped and blended before loading to the digester. Acid hydrolysis was done by adding 20ml 0.1M HCl with thorough mixing before purging with CO2 and sealing. Alkaline pretreatment was done using 1M NaOH. In both cases, the setups were exposed to heat at 1000C for 12hours, after which they were allowed to cool for 3 hours. The pH was modified to 6.7 – 7.2 before loading the inoculum and studying biogas generation. The large-scale setups with 1.0l, 1.5l, 5l and 10l capacity were studied for biogas generation. The results obtained show that thermochemical pretreatment results in more cumulative biogas production at 6200ml, followed by thermal at 4900ml and then chemical pretreatments at 3750ml for 500g mixed fruits and vegetable market wastes. Alkaline pretreatment is more efficient compared to acidic hydrolysis though highly influenced by proximate properties of the wastes and operation pH. The large-scale pretreatment resulted in 34500ml and 31400ml cumulative biogas from HCl and NaOH pretreatment. In conclusion, thermochemical pretreatment of market waste results in increased biogas generation resulting from hemicellulose breakdown and disrupting lignin-hemicellulose ether bonds in acid hydrolysis. In contrast, alkaline pretreatment leads to swelling of lignocelluloses and partial lignin solubilization lignin breakdown. The overall biogas generation depends on proximate waste matter and digester operation pH.

2018 ◽  
Author(s):  
Muhammad Junaid Khalid

Agricultural residues have high potential for biogas production, complex lignocellulosic structure is however the main hindrance in their bioconversion. This research focuses on combined effect of alkaline pretreatment of rice straw and magnetite (Fe3O4) nanoparticle application. Four doses of magnetite nanoparticles viz. 60, 80, 100 and 120 ppm were used in the anaerobic digestion of untreated and 2% NaOH pretreated rice straw. Compared to control, 2% NaOH pretreatment alone increased biogas and methane yield by 57 and 60% respectively. Magnetite nanoparticle (MNP) application alone gave maximum yield at 100 ppm which consisted of 37 and 33% more biogas and methane yield respectively. Combining the effect of 2% NaOH pretreatment and 120 ppm MNPs synergistically increased biogas and methane yield by 100 and 129% as compared to control. In addition, an energy assessment indicated a positive net gain of 3765 kJ for 2% NaOH pretreated rice straw with 120 ppm MNPs.


2020 ◽  
Vol 46 (3) ◽  
pp. 299-303
Author(s):  
Kulkarni Milind B. ◽  
P.M. Ghanegaonkar

Disposal of floral waste into water or landfill because of religious beliefs causes water and soil pollution. The purpose of present experimental work is to find an energy proficient solution for the disposal of floral waste. The method used in the present work includes anaerobic digestion of floral waste for biogas generation. The proposed method aims to follow waste-to-energy approach, for meeting the local energy demands. The techniques for getting enhanced biogas production from floral waste include novel alkaline chemical pretreatment of floral waste, and co-digestion of floral waste along with food waste. Alkaline chemical pretreatment of floral waste using sodium carbonate showed improved biogas production up to 106%, as compared to the traditional sodium hydroxide chemical pretreatment. Also, a reduction in the cost of chemical pretreatment up to 90% was possible. Co-digestion of floral waste along with food waste was also found effective for getting enhanced biogas output. A feedstock mixture of 70% of floral waste and 30% food waste could produce 32.6% more biogas than the singular feedstock in the form of floral waste. Alkaline pretreatment of floral waste using sodium carbonate and co-digestion with food waste seem to be the novelty of the work. Application of chemical absorption technique for biogas quality improvement could enrich the methane content of biogas up to 96%. Large-scale application of the proposed techniques of solid waste management can meet the energy demands at potential locations. The biogas with enriched methane content can suitable for widespread applications, such as vehicular applications and electricity generation for the benefit of the end users.


2015 ◽  
Vol 73 (4) ◽  
pp. 849-856 ◽  
Author(s):  
Valentine Nkongndem Nkemka ◽  
Yongqiang Li ◽  
Xiying Hao

Giant miscanthus (Miscanthus×giganteus) and Chinese fountaingrass (Pennisetum alopecuroides (L.) Spreng), cultivated for landscaping and soil conservation, are potential energy crops. The study investigated the effect of combined thermal and alkaline pretreatments on biogas production of these energy crops. The pretreatment included two types of alkali (6% CaO and 6% NaOH) at 22, 70 and 100 °C. The alkaline pretreatment resulted in a greater breakdown of the hemicellulose fraction, with CaO more effective than NaOH. Pretreatment of giant miscanthus with 6% CaO at 100 °C for 24 h produced a CH4 yield (313 mL g−1 volatile solids (VS)) that was 1.7 times that of the untreated sample (186 mL g−1 VS). However, pretreatment of Chinese fountaingrass with 6% CaO or 6% NaOH at 70 °C for 24 h resulted in similar CH4 yields (328 and 302 mL g−1 VS for CaO and NaOH pretreatments) as the untreated sample (311 mL g−1 VS). Chinese fountaingrass was more easily digestible but had a low overall CH4 yield per hectare (1,831 m3 ha−1 y−1) compared to giant miscanthus (6,868 m3 ha−1 y−1). This study demonstrates the potential of thermal/alkaline pretreatment and the use of giant miscanthus and Chinese fountaingrass for biogas production.


2016 ◽  
Vol 832 ◽  
pp. 55-62
Author(s):  
Ján Gaduš ◽  
Tomáš Giertl ◽  
Viera Kažimírová

In the paper experiments and theory of biogas production using industrial waste from paper production as a co-substrate are described. The main aim of the experiments was to evaluate the sensitivity and applicability of the biochemical conversion using the anaerobic digestion of the mixed biomass in the pilot fermentor (5 m3), where the mesophillic temperature was maintained. It was in parallel operation with a large scale fermentor (100 m3). The research was carried out at the biogas plant in Kolíňany, which is a demonstration facility of the Slovak University of Agriculture in Nitra. The experiments proved that the waste arising from the paper production can be used in case of its appropriate dosing as an input substrate for biogas production, and thus it can improve the economic balance of the biogas plant.


Author(s):  
Avantika Agarwal ◽  
Kunwar Paritosh ◽  
Pragati Dangayach ◽  
Priyanka Gehlot ◽  
Nidhi Pareek ◽  
...  

2001 ◽  
Vol 1 ◽  
pp. 908-913 ◽  
Author(s):  
Alex G. Fassbender

The Ammonia Recovery Process (ARP) is an award-winning, low-cost, environmentally responsible method of recovering nitrogen, in the form of ammonia, from various dilute waste streams and converting it into concentrated ammonium sulfate. The ThermoEnergy Biogas System utilizes the new chemisorption-based ARP to recover ammonia from anaerobically digested wastes. The process provides for optimal biogas production and significantly reduced nitrogen levels in the treated water discharge. Process flows for the ammonia recovery and ThermoEnergy biogas processes are presented and discussed. A comparison with other techniques such as biological nitrogen removal is made. The ARP technology uses reversible chemisorption and double salt crystal precipitation to recover and concentrate the ammonia. The ARP technology was successfully proven in a recent large-scale field demonstration at New York City’s Oakwood Beach Wastewater Treatment Plant, located on Staten Island. This project was a joint effort with Foster Wheeler Environmental Corporation, the Civil Engineering Research Foundation, and New York City Department of Environmental Protection. Independent validated plant data show that ARP consistently recovers up to 99.9% of the ammonia from the city’s centrate waste stream (derived from dewatering of sewage sludge), as ammonium sulfate. ARP technology can reduce the nitrogen (ammonia) discharged daily into local bodies of water by municipalities, concentrated animal farming operations, and industry. Recent advances to ARP enhance its performance and economic competitiveness in comparison to stripping or ammonia destruction technologies.


2013 ◽  
Vol 10 (2) ◽  
pp. 59-62
Author(s):  
Vladimír Sitkey ◽  
Ján Gaduš ◽  
Ľubomír Kliský ◽  
Alexander Dudák

Abstract Energy variety of amaranth (Amaranthus spp.) was grown in large-scale trials in order to verify the capability of its cultivation and use as a renewable energy source in a biogas plant. The possibility of biogas production using anaerobic co-fermentation of manure and amaranth silage was verified in the experimental horizontal fermentor of 5 m3 volume, working at mesophilic conditions of 38-40 °C. The goal of the work was also to identify the optimum conditions for growth, harvesting and preservation of amaranth biomass, to optimize biogas production process, and to test the residual slurry from digestion process as a high quality organic fertilizer. The average yield of green amaranth biomass was 51.66 t.ha-1 with dry matter content of 37%. Based on the reached results it can be concluded that amaranth silage, solely or together with another organic materials of agricultural origin, is a suitable raw material for biogas production.


Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3573 ◽  
Author(s):  
Meneses-Quelal Orlando ◽  
Velázquez-Martí Borja

The objective of this research is to present a review of the current technologies and pretreatments used in the fermentation of cow, pig and poultry manure. Pretreatment techniques were classified into physical, chemical, physicochemical, and biological groups. Various aspects of these different pretreatment approaches are discussed in this review. The advantages and disadvantages of its applicability are highlighted since the effects of pretreatments are complex and generally depend on the characteristics of the animal manure and the operational parameters. Biological pretreatments were shown to improve methane production from animal manure by 74%, chemical pretreatments by 45%, heat pretreatments by 41% and physical pretreatments by 30%. In general, pretreatments improve anaerobic digestion of the lignocellulosic content of animal manure and, therefore, increase methane yield.


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