Municipal Biomass Research Articles

Measurement of transient nanoparticle emissions of a municipal biomass incineration plant equipped with pulse-jet cleaned filters

The nanoparticle emission of a biomass incineration plant for district heating was investigated during a field measurement campaign. Pulse-jet cleaned filters were used as the main waste-gas treatment technology for the plant, downstream of a multi-cyclone which served as a pre-separator for the coarser size spectrum of fly ash particles. These filters feature a characteristic transient emission behavior consisting of distinct emission peaks, lasting from several seconds to many minutes after filter regeneration. This transient behavior required the development of an adapted measurement setup and methodology when using a scanning mobility particle sizer (SMPS) for the determination of the size distribution. The concentration of particle size fractions (during both, SMPS scans and measurements with fixed classifier voltage) and the total concentration were measured simultaneously applying two condensation particle counters (CPC). The decay behavior of the emission peaks of certain size fractions (at fixed classifier voltage) and the total concentration are in good agreement, enabling post-processing of the SMPS scans, which are affected by the inlet concentration decay during measurement. The size distributions of the particle emission from filter bags made of needle-felt media (aged and newly installed) and of membrane filter medium with taped seams (newly installed) were obtained following the measurement methodology. The emission of the aged needle-felt and the membrane filter medium rapidly declined to zero, allowing only for a single scan for each regeneration event. The membrane filter medium shows the lowest emission at an average number concentration of approx. 13 #/cm³ with a number-based median diameter x50,0 of 70 – 80 nm. The results demonstrate the possible high number based separation efficiency (e.g. above 99.999 % for the membrane filter bag) of pulse-jet cleaned filters regarding particle sizes not properly represented by conventional gravimetrical measurements.

Study on energy conversion efficiency of biomass continuous carbonisation in municipal domestic sewage based on filtration technology

In order to overcome the problem that the energy conversion efficiency of municipal sewage carbonisation is not clear, the research method of energy conversion efficiency of municipal sewage biomass continuous carbonisation based on filtration technology is proposed. In order to obtain the municipal domestic sewage, SBR dephosphorisation device was used to dephosphorise the domestic sewage. Based on the filtration technology, biological aerated filter and A/O biological filter were used to filter the domestic sewage after dephosphorisation to complete the extraction of biomass. The experimental results show that in the period of 1-30 s, the energy conversion efficiency of biomass carbonisation shows an upward trend, the maximum value is 0.94; in the period of 31-40 s, the energy conversion efficiency of biomass carbonisation shows a downward trend. Through the experiment, it can be clear that the energy conversion efficiency of biomass continuous carbonisation in different periods of time.

Bahir Dar City Municipal Solid Waste Potential Assessment for Clean Energy

Nowadays, Carbon-rich fuels are the principal energy supply utilized for powering human society, and it will be continued for the next some decades. Connecting with this, modern energy technologies are very essential to convert the available limited carbon-rich fuels and other green alternative energies into useful energy efficiently with an insignificant environmental impression. Therefore, the main objectives of this study are assessing the potential of municipal biomass solid waste for briquette production in Bahir Dar city, Ethiopia. To conduct this research, various data collection instrument tools were used to achieve the intended objectives for instance questionnaire, direct measurement, field observation and related literature based on necessity. Moreover, to confirm the reliability of the information obtained through a questionnaire, a focus group discussion was conducted with different concerned bodies. The main finding of this study shows that Bahir Dar city has the potential to generate 50.19 tons of municipal biomass solid waste per day. The collected waste was characterized as 82.5% of them is organic waste that may be converted in to clean energy (briquette and biogas) based on their sized whereas the remaining 17.5% of them were inorganic (plastics, glass, and metals) that can be resent for recycling and reuse to their original sources. Biomass-related solid municipal waste is a promising potential to utilize as a feedstock for briquette production. Besides, it has a prodigious role to reduce deforestation, land degradation, save foreign currency and reduce greenhouse gas emissions. This is because the demands of household’s energy that was fulfilled with wood charcoals and fossil fuels are substituted with locally available renewable energy sources. The experimental results confirmed that all the physicochemical properties of briquette charcoal that are produced from municipal solid biomass waste were acceptable. Besides, the burning efficiency of the briquette, fanning time and carbon content determination were measured and obtained as adequate results based on the standards. Hence, it will be a possible alternative fuel for household energy using a special design stove that is available in the market. It has also played a great role in waste management and treatment system to achieve sustainable clean city developments.

Ultrasonic-microwave Pretreatment of Municipal Biomass Wastes for Enhanced Saccharification Production

Saccharification is commonly considered to be a rate-limiting step in the Bioethanol process from Biomass material. In order to improve the cellulose enzyme catalytic reaction efficiency, Ultrasonic & Microwave co-pretreatment (UMCP) prior to enzyme hydrolysis is employed to depolymerize the biomass recalcitrance of Municipal biomass wastes (MBW) to improve saccharification efficiency. The results showed that Ultrasonic & Microwave co-pretreatment efficiently broken the compact structure of MSW and result in higher saccharification rate compared with untreated samples. The reducing sugars yield was 200.3mg/g, higher than the original value 91.8mg/g under the same enzyme hydrolysis conditions. And UMCP-alkaline or acid yield higher saccharification production.

The evaluation of heat production using municipal biomass co-incineration within a thermal power plant

Wastewater treatment plants provide two final products, purified water and waste in the forms of liquid and solid phases. Municipal biomass from wastewater treatment plants represents a rising problem since its disposal is prohibited by a European environmental directive. Currently the more popular are municipal biomass combustion and co-combustion in power plants or waste incineration plants, because the dry municipal biomass has similar calorific value as brown coal. An addition of up to 5% of municipal biomass to the system for electricity production from fossil fuels is allowed according to the European Directives and Slovenian legislation. Following these criteria the addition of around 1730 kg/h of municipal biomass with 60% of moisture is allowed in accordance with the reference thermal power plant operational data. This paper presents analyses regarding the usages of different amounts of municipal biomass in the reference thermal power plant for which process simulation is done using the Aspen Plus programme package. Furthermore, the analysis of hazardous metals such as Pb, Hg and Cd concentrations in flue gases are determined and the economic evaluation of municipal biomass exploitation within the thermal power plant is also presented.

County government led EIP development using municipal biomass resources for clean energy production, a case study of the Catawba County North Carolina EcoComplex

The Catawba County North Carolina, USA EcoComplex and Resource Recovery Facility is an eco-industrial park (EIP) whose mission is synergistic waste and resource management, renewable energy production, and local economic development through public and private partnerships. The EcoComplex is a 326 hectare site centred on the Blackburn Landfill with 2.4 million metric tons of waste in place and serves the 156,000 county residents, receiving 484 tons/day of MSW and 80 tons of construction wastes per day. The site hosts a grid-tied 3MW landfill gas to energy project (LFGTE) using three GE-Jenbacher spark-ignition engines, a biodiesel facility with 379,000 LPY capacity and a crop processing facility that provides feedstock utilising buffer lands on-site to grow oilseed crops. This paper details the existing and impending biomass energy systems, applications of industrial symbiosis, and the use of public and private partnerships to leverage this municipal landfill as a hub for clean energy development.

Benefit-cost analysis of hybrid willow crop production on agricultural land in eastern Canada: Assessing opportunities for on-farm and off-farm bioenergy use

The purpose of this study was to conduct a financial benefit-cost analysis of producing hybrid willow biomass on riparian, in-field, and high-sloped agricultural land in the eastern Canadian province of Prince Edward Island for use as an on-farm or off-farm source of renewable energy. The off-farm use analysis indicated that, at a current price of $50 per dry matter tonne (DMT−1) sold to a municipal biomass energy plant, the willow cropping system would not represent an attractive investment opportunity for farmers. Prices would have to increase to the range of $81–$116 DMT−1 (depending on the scenario considered) before such an investment would be profitable. On the other hand, the on-farm use analysis indicated that, at an estimated cost savings of $375 DMT−1 from displacing heating oil by using a biomass boiler to burn the willow chips (at a replacement cost of $56–$137 DMT−1, depending on the scenario), the willow cropping system would represent a very attractive investment opportunity for farmers. Using such a system could reduce heating costs on the farm in the range of 64–85%.

Anaerobic co-digestion of municipal biomass wastes and waste activated sludge: Dynamic model and material balances

The organic matter degradation process during anaerobic co-digestion of municipal biomass waste (MBW) and waste-activated sludge (WAS) under different organic loading rates (OLRs) was investigated in bench-scale and pilot-scale semi-continuous stirred tank reactors. To better understand the degradation process of MBW and WAS co-digestion and provide theoretical guidance for engineering application, anaerobic digestion model No.1 was revised for the co-digestion of MBW and WAS. The results showed that the degradation of organic matter could be characterized into three different fractions, including readily hydrolyzable organics, easily degradable particulate organics, and recalcitrant particle organics. Hydrolysis was the rate-limiting step under lower OLRs, and methanogenesisis was the rate-limiting step for an OLR of 8.0 kg volatile solid (VS)/(m3·day). The hydrolytic parameters of carbohydrate, protein, and lipids were 0.104, 0.083, and 0.084 kg chemical oxygen demand (COD)/(kg COD·hr), respectively, and the reaction rate parameters of lipid fermentation were 1 and 1.25 kg COD/(kg COD·hr) for OLRs of 4.0 and 6.0 kg VS/(m3·day). A revised model was used to simulate methane yield, and the results fit well with the experimental data. Material balance data were acquired based on the revised model, which showed that 58.50% of total COD was converted to methane.

Effects of lipid concentration on anaerobic co-digestion of municipal biomass wastes

The influence of the lipid concentration on the anaerobic co-digestion of municipal biomass waste and waste-activated sludge was assessed by biochemical methane potential (BMP) tests and by bench-scale tests in a mesophilic semi-continuous stirred tank reactor. The effect of increasing the volatile solid (VS) concentration of lipid from 0% to 75% was investigated. BMP tests showed that lipids in municipal biomass waste could enhance the methane production. The results of bench-scale tests showed that a lipids concentration of 65% of total VS was the inhibition concentration. Methane yields increased with increasing lipid concentration when lipid concentrations were below 60%, but when lipid concentration was set as 65% or higher, methane yields decreased sharply. When lipid concentrations were below 60%, the pH values were in the optimum range for the growth of methanogenic bacteria and the ratios of volatile fatty acid (VFA)/alkalinity were in the range of 0.2–0.6. When lipid concentrations exceeded 65%, the pH values were below 5.2, the reactor was acidized and the values of VFA/alkalinity rose to 2.0. The amount of Brevibacterium decreased with increasing lipid content. Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process, thereby inhibiting anaerobic digestion.

Experimental Study on the Co-Firing Power Generation of Municipal Solid Waste and Biomass

Much attention has been paid to municipal solid waste (MSW) incineration power generation and biomass energy. The co-firing power generation tests of MSW and biomass were performed in a MSW incineration power plant in North China. Experimental results showed that the running efficiency of generator unit had achieved the optimum state when the blended ratio was 14% (w%); the concentration of fly ash decreased greatly, and the concentration of SO2 and NOX increased slightly. These contents can be referenced in the running of MSW incineration power plant and the using of biomass energy later.

Mitigating ammonia inhibition of thermophilic anaerobic treatment of digested piggery wastewater: Use of pH reduction, zeolite, biomass and humic acid

High free ammonia released during anaerobic digestion of livestock wastes is widely known to inhibit methanogenic microorganisms and result in low methane production. This was encountered during our earlier thermophilic semi-continuously fed continuously-stirred tank reactor (CSTR) treatment of piggery wastewater. This study explored chemical and biological means to mitigate ammonia inhibition on thermophilic anaerobic treatment of piggery wastewater with the aim to increase organic volatile carbon reduction and methane production. A series of thermophilic anaerobic batch experiments were conducted on the digested piggery effluent to investigate the effects of pH reduction (pH 8.3 to 7.5, 7.0 and 6.5) and additions of biomass (10% v/v and 19% v/v anaerobic digested piggery biomass and aerobic-anaerobic digested municipal biomass), natural zeolite (10, 15 and 20 g/L) and humic acid (1, 5 and 10 g/L) on methane production at 55 °C for 9–11 days. Reduction of the wastewater pH from its initial pH of 8.3 to 6.5 produced the greatest stimulation of methane production (3.4 fold) coupled with reductions in free ammonia (38 fold) and total volatile fatty acids (58% TVFA), particularly acetate and propionate. Addition of 10–20 g/L zeolite to piggery wastewater with and without pH reduction to 6.5 further enhanced total VFA reduction and methane production over their respective controls, with 20 g/L zeolite producing the highest enhancement effect despite the ammonia-nitrogen concentrations of the treated wastewaters remaining high. Without pH reduction, zeolite concentration up to 20 g/L was required to achieve comparable methane enhancement as the pH-reduced wastewater at pH 6.5. Although biomass (10% v/v piggery and municipal wastes) and low humic acid (1 and 5 g/L) additions enhanced total VFA reduction and methane production, they elevated the residual effluent total COD concentrations over the control wastewaters (pH-unadjusted and pH-reduced) unlike zeolite treatment. The outcomes from these batch experiments support the use of pH reduction to 6.5 and zeolite treatment (10–20 g/L) as effective strategies to mitigate ammonia inhibition of the thermophilic anaerobic treatment of piggery wastewater.

Pilot-scale anaerobic co-digestion of municipal biomass waste and waste activated sludge in China: Effect of organic loading rate

The effects of organic loading rate on the performance and stability of anaerobic co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) were investigated on a pilot-scale reactor. The results showed that stable operation was achieved with organic loading rates (OLR) of 1.2–8.0kgvolatile solid (VS)(m3d)−1, with VS reduction rates of 61.7–69.9%, and volumetric biogas production of 0.89–5.28m3(m3d)−1. A maximum methane production rate of 2.94m3(m3d)−1 was achieved at OLR of 8.0kgVS(m3d)−1 and hydraulic retention time of 15days. With increasing OLRs, the anaerobic reactor showed a decrease in VS removal rate, average pH value and methane concentration, and a increase of volatile fatty acid concentration. By monitoring the biogas production rate (BPR), the anaerobic digestion system has a higher acidification risk under an OLR of 8.0kgVS(m3d)−1. This result remarks the possibility of relating bioreactor performance with BPR in order to better understand and monitor anaerobic digestion process.

Pilot-scale anaerobic co-digestion of municipal biomass waste: Focusing on biogas production and GHG reduction

Abstract A pilot-scale anaerobic co-digestion research study is presented to elucidate the feasibility of developing anaerobic digestion (AD) as an effective disposal method for municipal biomass waste (MBW) in China, focusing on biogas production and greenhouse gas (GHG) reduction. Food waste, fruit–vegetable waste, and dewatered sewage sludge were co-digested in a continuous stirred-tank reactor for biogas production. Stable operation was achieved with a high biogas production rate of 4.25 m3 (m3 d)−1 at organic loading rate of 6.0 kgVS (m3 d)−1 and hydraulic retention time of 20 d. A total of 16.5% of lipids content was beneficial to the biogas production of the feedstock without inhibition to anaerobic digestion. Compared with the landfill baseline, GHG reduction is an important environmental benefit from MBW digestion. Therefore, anaerobic co-digestion is a promising alternative solution for MBW because it contributes significantly to the sound management of municipal solid waste in China.

Effect of thermal pretreatment on the physical and chemical properties of municipal biomass waste

The effects of thermal pretreatment on the physical and chemical properties of three typical municipal biomass wastes (MBWs), kitchen waste (KW), vegetable/fruit residue (VFR), and waste activated sludge (WAS) were investigated. The results show that thermal pretreatment at 175 °C/60 min significantly decreases viscosity, improves the MBW dewatering performance, as well as increases soluble chemical oxygen demand, soluble sugar, soluble protein, and especially organic compounds with molecular weights >10 kDa. For KW, VFR and WAS, 59.7%, 58.5% and 25.2% of the organic compounds can be separated in the liquid phase after thermal treatment. WAS achieves a 34.8% methane potential increase and a doubled methane production rate after thermal pretreatment. In contrast, KW and VFR show 7.9% and 11.7% methane decrease because of melanoidin production.

Evaluation of biogas production from different biomass wastes with/without hydrothermal pretreatment

Municipal biomass waste is regarded as new available energy source, although it could cause serious environmental pollution. Generally, biogas recovery by anaerobic digestion was seen as an ideal way to treat biomass waste. Different types of biomass waste have different biogas production potential. In this paper, cow manure, pig manure, municipal sewage sludge, fruit/vegetable waste, and food waste were chosen as typical municipal biomass waste. In addition, hydrothermal pretreatment was used to accelerate digestion and increase biogas production. Biochemical methane potential (BMP) test was used to evaluate biogas production for raw biomass and hydrothermal treated waste. Raw materials of fruit/vegetable and food waste show higher methane production than that of cow manure, pig manure, and municipal sewage sludge. After hydrothermal pretreatment at typical condition (170 °C at 1 h), the biogas production of pig manure, cow manure, fruit/vegetable waste, and municipal sewage sludge increased by 7.8, 13.3, 18.5, and 67.8% respectively. While, for treated food waste, the biogas decrease by 3.4%. The methane yield of pig manure, fruit/vegetable waste, and municipal sewage sludge increased by 14.6, 16.1, and 65.8%, respectively. While, for treated cow manure and food waste, the methane decrease by 6.9% and 7.5%.

A Unified Biomass-Coal Pyrolysis Reaction Model

A unified first order reaction rate model of pyrolysis is presented to facilitate co-utilization of domestic fuels (CDF) spanning the entire coalification region. This model was first used in interpretations of University of Florida laboratory and industrial scale coal-natural gas (C-NG) co-firing experiments using reaction rates based upon coal pyrolysis yields measured at MIT. After undertaking industrial-scale municipal solid waste, biomass, coal, and natural gas co-firing experiments, the pyrolysis model was used to interpret experiments with these fuels. The model is here adapted to represent ultra pyrolysis (UP) yields of cellulose measured at the University of Western Ontario (UWO) and fast pyrolysis (FP) yields of eight coals of various ranks measured at Tohoku University (TU). The overall goal is to find equations to calculate FP yields that depend upon the weight percentages [C], [H], and [O] of the feedstock, the a, b, and c of the chemical product (C a H b O c ), the temperature of pyrolysis (T), and the time (t) of application of this temperature. Such a unified model should be useful for many CDF applications and helpful in bringing order to the science of pyrolysis.

Strategies for sludge handling in the Stockholm region

The annual production of dewatered sludge from the municipal wastewater treatment plants handled by Stockholm Water Company is about 75,000 tonnes. The policy of Stockholm Water Company is to find methods to use the sludge as a resource by recovering its contents of nutrients and earth-forming substances. The most suitable sludge use is considered to be for agriculture. Intensive work has been done on reducing the sludge concentration of toxic metals and other pollutants by use of control of discharges of industrial waters into the sewer network, information campaigns to households, and improved management of storm water. The sludge quality is measured by automatic samplers for dewatered sludge and analyses of heavy metals and certain organic pollutants. Sludges with better quality than limiting values from authorities may safely be used in agriculture, while sludges not fulfilling stringent requirements must be handled by other methods. Due to resistance from the food industry and a number of interest organisations, it is important to find other handling methods also for high quality sludges. Such methods include the use of incineration together with municipal solid wastes or biomass or separation of the sludge into different products for internal or external use.