Residual Waste Research Articles

Effects of adding different ratios of residual sludge and food waste co-anaerobic fermentation liquid to AAO wastewater treatment process

Carbon sources are the main bottleneck which limit the biological treatment of wastewater. In this study, the effects of temperature on the preparation of RFCF and focused on exploring the removal of pollutants in wastewater treatments by the addition of different ratios of CFRF were investigated using residual sludge and food waste co-anaerobic fermentation liquid (RFCF) as external carbon sources. The results showed that anaerobic fermentation at 40 °C had elevated the concentrations of NH4+-N, TN, and volatile fatty acids (VFAs) in the RFCF. It was found that under anaerobic fermentation at 20 °C, increases in RFCF additions significantly increased the average removal rates of NH4+-N, TN and TP by 30.44 %, 66.51 % and 60.90 %. The increase in nitrogen and phosphorus removal efficiency was mainly attributed to the increase of RFCF addition promoting the relative abundance of denitrifiers, denitrification functional genes and phosphate accumulating organisms (PAOs), and phosphorus metabolism functional genes. The control guidelines for the RFCF addition amounts were dependent on the pollutant removal indexes. Therefore, this study is an important guide to the practical engineering application of RFCF.

Life-cycle economic and environmental impacts of municipal solid waste reverse logistics in residential areas

The economic and environmental impacts of the reverse logistics (RL) process (including drop-off, collection and transportation [C&T]) of the waste disposal chain are becoming increasingly prominent with the increasing generation of municipal solid waste (MSW) and promotion of MSW classification. Quantitative evaluation of this process from economic and environmental perspectives is of great significance for MSW management. This study focused on the financial capital, materials, and energy consumption in the RL process in Xi an City, China. Based on field investigation, the magnitude of pollutant emissions from MSW C&T vehicles over their life cycle was predicted using the GREET software and total RL life-cycle cost and life-cycle assessment were analyzed. The results showed that the finical costs of RL were $46.35–$49.03 per ton of food waste and $62.52–$88.84 per ton of residual waste; the environmental impacts caused by the RL process accounted for 79.24%–96.00% and 20.87%–68.55% of the entire food waste and residual waste management chains, respectively. Labor costs were the biggest financial expenditure and the fuel cycle of C&T vehicles caused the majority of the environmental impacts. Source-separated waste management scenarios represented more environmental benefits but poorer economic positions. In the future, improving MSW source-separation accuracy, replacing diesel C&T vehicles with electric ones, and optimizing the RL system could reduce the environmental and economic impacts of the entire waste management system.

Survey and reduction of waste production from eye surgery

The health sector is facing new challenges due to the impact of climate change on health. At the same time, it significantly contributes to our society's climate footprint. Hospitals producing considerable amounts of waste are an important aspect of this burden. The aim of this work was to quantify the amount of waste produced by eye surgery and, as an optimization measure, to evaluate the effect of glass separation from residual waste. Over a2-week period, the waste generated by eye operations in the surgical theater of our university hospital was measured. Another 2‑week long measurement was conducted after the initiation of glass separation from general waste. The data obtained allowed acomparison of the two periods, the type of waste (residual and recyclable) as well as the type of operation (intraocular, extraocular). Considering regional waste disposal costs, an economic comparison was also performed. In the first measurement period (196 operations), atotal of 549.6 kg of waste was generated, 87% (478.3 kg) of which was residual waste, corresponding to 14.3tons of total waste annually. Intraocular procedures generated on average 80% more waste than extraocular procedures: 18.1 ± 3.9 kg and 11.4 ± 4.0 kg, respectively, per day and theater. Separation of glass from residual waste reduced its quantity by 7.2% in the second measurement period (197 procedures). As the disposal of glass is free of charge in the city of Essen, this resulted in asmall economic advantage (extrapolated to 112 € per year). The amount of waste generated by ophthalmic surgery is substantial, with apredominant proportion of non-recyclable residual waste. Intraocular operations are the cause of the majority of the waste produced. Simple measures, such as disposing of glass separately, are helpful and inexpensive to reduce the quantity of residual waste.

Assessment of Melt Compounding with Zeolites as an Effective Deodorization Strategy for Mixed Plastic Wastes and Comparison with Degassing.

The emission of off-odors from mechanically recycled plastics severely limits their re-introduction into the market for the production of new objects, for the same use or even for less demanding applications, thus hindering the implementation of an effective circular economy for plastics. The addition of adsorbing agents during the extrusion of polymers represents one of the most promising strategy to reduce the odorous emissions of plastics, due to its characteristics of cost-effectiveness, flexibility and low energy consumption. The novelty of this work lies in the assessment of zeolites as VOC adsorbents during the extrusion of recycled plastics. They appear more suitable than other types of adsorbents, due to their ability to capture and "hold" the adsorbed substances at the high temperatures of the extrusion process. Moreover, the effectiveness of this deodorization strategy was compared with the traditional degassing technique. Two types of mixed polyolefin wastes, coming from completely different collection and recycling processes, were tested: Fil-S (Film-Small), deriving from post-consumer flexible films of small size, and PW (pulper waste), which is the residual plastic waste obtained from the paper recycling process. The melt compounding of the recycled materials with two micrometric zeolites (zeolite 13X and Z310) resulted as more effective in the off-odors removal with respect to degassing. In particular, the highest reduction (-45%) of the Average Odor Intensity (AOI) was measured for both PW/Z310 and Fil-S/13X systems at 4 wt% of the zeolites' amount, compared with the corresponding untreated recyclates. Finally, by combining degassing and melt compounding with zeolites, the best result was obtained for the composite Fil-S/13X, whose Average Odor Intensity resulted as quite close (+22%) to the one of the virgin LDPE.

An innovative LFC scheme for multi-area microgrid incorporating with hydrogen-based demand response mechanism

Due to the unpredictability of renewable energy sources (RESs) in Microgrids (MG), the Load Frequency Control (LFC) mechanism is crucial for frequency management of these systems. Frequency control in MGs can be made more cost-effective with the help of demand-side management by temporarily boosting or decreasing power usage, in addition to Automatic Generation Control (AGC) techniques. Hydrogen can provide considerable benefits to MGs since it can be used in two ways: as a fuel cell for electricity generation or as an electrolyzer for power consumption, satisfying the needs of AGC and demand response (DR) simultaneously utilizing Hydrogen Energy Storage (HES) system. This research proposes an MG structure that integrates appropriate energy storage technologies, is able to provide both energy and waste management, and enables use of a variety of RES (including solar, wind, wastewater, agricultural, and residential wastes). With the newly announced Improved-Salp Swarm Algorithm (ISSA), this research aims to design a novel double-input interval type-2 fuzzy fractional order proportional-integral-derivative PI + TID (DIT2-FOPI + TID) cascade controller for LFC of multi-area MGs considering DR with a broad range of Distributed energy resources (DER). In all case studies, the proposed controller demonstrates outstanding effectiveness within the setting of LFC of MGs and, especially by employing DRM approaches, boosts frequency response performance by up to 65%. The results indicate that the dynamic frequency response of the MG is significantly enhanced by the addition of DRM capability with the HES system.

Potential applicability of Jatropha curcas leaves in bioethanol production and their composites with polymer in wastewater treatment

Among the biggest issues facing the world now are fuel shortages and water contamination. Therefore, the goal of the current study was directed to produce bioethanol from Jatropha curcas leaves and use the residual wastes in the form of composite sheets for crystal violet (CV) removal. The leaves were collected from Jatropha curcas, irrigated by various irrigation sources; sewage-water (A), sewage-water-sludge (B), and tap water (C). The acid hydrolysis (4% H2SO4) of these leaves demonstrated that the hydrolysis of the Jatropha curcas leaves (A) produced higher values of total reducing sugars (≈ 21 g/l) than other leaves (B &C). Moreover, the bioethanol concentrations obtained from the fermentation of this hydrolysate (A) at the bioreactor scale using Candida tropicalis and Saccharomyces cerevisiae (≈10 and 7 ml/l, respectively) were relatively increased compared to the flask level (≈7 and 5 ml/l, respectively). Afterwards, the unhydrolyzed wastes were dried, grinded, and embedded in polyvinyl chloride (PVC) polymer forming sheets. The sheets were characterized using FT-IR, SEM, swelling, and porosity. The highest CV removal percent of 95.39%, after optimization, was achieved at 100 ppm crystal violet concentration using 2.5 g/l from PVC-A composite sheet after 180-min contact time.

A Deep Learning-Based approach to Segregate Solid Waste Generated in Residential Areas

Residential waste is a substantial contributor to solid waste generation, which is approximately around 36.5 million tons annually in India. The waste created in households is not separated at the source. All waste is accumulated in a single waste bin and stashed in a nearby public waste bin, resulting in a massive amount of waste being dumped in landfills and also infused with other types of waste, causing environmental pollution. The core objective of this research is to develop a household waste segregator using the TensorFlow object detection model and Arduino microcontroller. The SSD MobileNet V2 model has been trained with a household dataset consisting of paper, plastic, metal, organic waste, glass, and one more additional empty class to detect whether waste is placed for detection or not. This proposed system can predict the waste class and segregate it into their specific dustbin with mean Average Precision (mAP) and recall of 86.5% and 88.3%, respectively. Waste segregation and recycling can reduce landfills, lower carbon footprints, increase recycling, recover value from garbage, and lower greenhouse gases emitted from waste. Segregation at the source will reduce the cost of the segregation process carried by the municipal solid waste management.

Material Flow and Waste Recovery in a Community-Based Waste Management System in Batu, Indonesia

Indonesian government has promoted to establish Community Based Waste Management (CBWM) in Indonesia to increase the resource recovery rate and to reduce the amount of landfilling waste in stead of conventional the waste management. In CBWM, recyclable materials are recovered by neighborhood communities and only the residual waste is landfilled. Although CBWM can contribute to the reduction of green house gas emission and conservation of resources, the effectiveness of CBWM on the reduction of waste is an clear due to a lack of detailed information about CBWM such as economic benefit, waste flow and its sustainability. The aims of this study are to identify the waste flow in common CBWM in Indonesia and to evaluate the effectiveness of CBWM for reduction of MSW carried to a landfill site. The TPS3R Dadaprejo Mandiri (DM-TPS) in Dadaprejo Village, Batu City, Indonesia was investigated as a case of CBWM. Waste composition was surveyed for 8 consecutive days on three separate occasions in 2021 and 2022. Each resource was weighed and measured at each step of the process to analyze waste flow. Monthly data summarizing the amount of each resource separated at DM-TPS was obtained from their records. Information about the amount of waste and resources collected by the 13 waste banks was obtained by interviewing the administrators of those waste banks. The amount of waste carried to DM-TPS during the first, second, and third surveys averaged 5.61, 6.65, and 5.40 t/day, respectively. Of the 9 categories of waste, the largest was the organic waste. Fruits and vegetables made up the largest percentage of resources followed by plastic bags. The average resource recovery rate was approximately 15.2%. However, the composition survey revealed that the potential resource recovery rate was approximately 39.5%. In order to increase of resource recovery rate, the corporation of households on simple source separation at home would be required.

Analysis of complex fluid discharge from consumer dispensing bottles using rheology and flow visualization

Abstract Complex fluids, such as gels, shampoos, and creams, are ubiquitous in the consumer product industry. However, little information is available on their discharge from consumer packaging, often resulting in a considerable heel, i.e., the residual waste material after the discharge process is complete. Here, we used rheological analysis and particle image velocimetry (PIV) to investigate the discharge of rheologically different fluids from a dispensing bottle provided with a modified hand pump. The fluids were described in terms of rheological parameters established by fitting rheometric data with the Carreau equation. The effect of operational parameters was also studied, which included the dip tube diameter, suction pressure, and volumetric flow rate. The data were also analyzed in terms of the dimensionless region of interest (ROI), which captures the relative “high-velocity” region in the fluid during the discharge process and is measured directly using PIV. Both rheological and operational parameters affect the heel at the end of the discharge process. The results presented here enable predicting the heel either by measuring ROI as in the case of transparent fluids and packages or by making use of the heel correlation with operational and rheological parameters also established in this work.

Household and household-related waste generation and characteristics in rural areas: A case study in Tanjungsari Sub-district

Waste management issues in rural locations differ from those in metropolitan ones. Unmanaged waste has the potential to harm the rural environment. Understanding the generation and characteristics of household and household-related waste is the starting point for planning waste management. Accurate measurement of waste generation and characteristics helps optimize waste reduction and recycling efforts. Therefore, this study aims to measure the waste generation and characteristics in rural areas using the Indonesia National Standard 19-3964-1994 method. The survey team visited 60 samples of residential and non-residential properties in the Tanjungsari Sub-district for eight consecutive days. Based on the results, the waste generation was 0.34 kg person-1 day-1. Organic waste (food waste, leaves, paper, and wood) accounts for the majority of garbage (81,34%), followed by inorganic materials (plastic, fabric, other materials, metal, and glass) at 15.66%, 1.86%, 0.91%, 0.12%, 0.11% respectively. The residential waste density is 196.1 kg m-3, while in non-residential areas is 63.63 kg m-3. Family size and income, living habits, and the type of economy or industry that develops have influenced the rural waste generation and composition. Rural waste management strategies need to consider organic waste as a raw material in composting or fermentation.

Composite Beams Made of Waste Wood-Particle Boards, Fastened to Solid Timber Frame by Dowel-Type Fasteners

To increase the sustainability of prefabricated timber buildings and constructions, composite timber beams with "box" cross-sections were developed in collaboration with an industry partner. They were constructed from a solid timber frame and from webs made of residual waste wood-particle boards from prefabricated timber buildings production. The developed beams' design concepts presented in this paper were governed by architectural features of prefabricated timber buildings, geometrical limitations, available production technology, and structural demand related to various possible applications. The paper presents the results of experimental bending tests of six variations of the developed composite timber beams constructed by mechanical fasteners only. The developed design concept of composite timber beams without adhesives is beneficial compared to glued beams in terms of design for deconstruction and lower VOC emissions. The tests were conducted to study the influence of the following parameters on the beams' mechanical behavior: (i) web material (oriented strand boards (OSBs) vs. cement-particle boards); (ii) the influence of beam timber frame design (flanges and web stiffeners vs. flanges, web stiffeners, and compressive diagonals), and (iii) the influence of stiffener-flange joint design. Besides the beams' load-bearing capacities, their linear and non-linear stiffness characteristics were the main research interest. While adding compressive timber diagonals did not prove to significantly increase the stiffness of the beams in the case of cement-particle board webs, it increased their load-bearing capacity by enabling the failure of flanges instead of prior webs and stiffener-flange joints failure. For beams with OSB webs, failure of the bottom flange was achieved already with the "basic" timber frame design, but timber diagonals proved beneficial to increase the stiffness characteristics. Finally, mechanical characteristics of the developed beams needed in structural design for their application are provided together with further development guidelines.

The Calorific Value Experiment of Refuse Derived Fuel by Utilizing Residual Waste to Produce Energy

Refuse Derived Fuel (RDF) is excellent process to reuse the wastes from human activities or residual waste becomes renewable energy and also cut off the wastes volumes prior to transporting to landfill, it is an apart of supporting climate change mitigation due to waste generation and green house affect. This study is to focus on: 1. study on ratio of the waste material component to produce the RDF and, 2. testing and find out the RDF properties and calorific value of each material component. Therefore, according to the experiments found that, the mixtures of the plastics and dry leaves, plastics and papers, papers and dry leaves and plastics, papers and dry leaves indicated the calorific value are 14.91( ), 14.11( ), 15.02( ), 14.91( ) and 15.39 ( ), respectively.

Optimization of Briquette Fuels by Co-Torrefaction of Residual Biomass and Plastic Waste Using Response Surface Methodology

Combining biomass, a clean and renewable energy source, with waste plastic, which serves as a good auxiliary fuel, can produce high-quality clean fuel. The performance of biomass-derived fuel can be improved by torrefaction. This study optimized the co-torrefaction of fungus bran and polypropylene (PP) waste plastic to obtain clean solid biofuel with high calorific value and low ash content (AC) using response surface methodology. Two sets of mixed biochars were investigated using a multiobjective optimization method: mass yield-higher heating value-ash content (MY-HHV-AC) and energy yield-ash content (EY-AC). PP increased the heat value, decreased AC, and acted as a binder. The optimal operating conditions regarding reaction temperature, reaction time, and PP blending ratio were 230.68 °C, 30 min, and 20%, respectively, for the MY-HHV-AC set and 220 °C, 30 min, 20%, respectively, for the EY-AC set. The MY-HHV-AC set had properties close to those of peat and lignite. Furthermore, compared with that of the pure biochar, the AC of the two sets decreased by 15.71% and 14.88%, respectively, indicating that the prepared mixed biochars served as ideal biofuels. Finally, a circular economy framework for biobriquette fuel was proposed and prospects for preparing pellets provided.

Properties and Uses of Biochars Incorporated into Mortars

The construction industry is responsible for a large amount of CO2 emissions and an intensive energy consumption. Cement production is the third largest source of anthropogenic CO2 emissions and is responsible for about 1.8 Gt of CO2 emissions into the atmosphere. The use of waste materials to replace a fraction of cement in the mortar makes it more economically and ecologically friendly. In this work, the main objective was to test incorporations of biochar produced at temperatures of 300, 350, and 400 °C, as a partial replacement for cement in the production of mortar. The materials used for the tests were residual lignocellulosic biomass (WBL) and electrical cable insulation waste (WIEC) mixed in a ratio of 1:1. The biochars produced were crushed and sieved after production to reduce the particles. A sample of biochar was used and tested under these conditions and another sample was washed in water and dried before being incorporated; all tests were carried out with a 5% replacement. Waste recovery tests were also carried out without thermochemical treatment. The specimens were studied for compressive strength and water absorption by immersion. All tests were replicated and were analyzed and compared with a control mixture with no incorporation of biochar in the mixture. It was possible to observe that the tests with the incorporation of biochars at 400 °C showed better results, with only a 24% reduction in resistance to compression.

Production of enriched cakes by apple pulp and peel powder and evaluation of chemical, functional and textural properties

Background: Apple pomace is a by-product of the fruit juice industry and comprises peel, seed, stem, and pulp tissues. This by-product contains dietary fiber, polyphenols, vitamins, and organic acids that can benefit human health and have a high potential as a dietary source. Baked products are well-known food types to humans and have a key role in feeding people worldwide. Nowadays, enriched products such as bread, cakes, and biscuits are available in stores. Different studies worldwide have been done about applying fruit juice industry by-products in the bakery. Objective: This research aimed to evaluate apple peel (APE) and pulp (APU) powders separately as a partial substitute for wheat flour in cake production. Methods: Apple peels and pulp, separately produced as residual wastes of juicing, were dried for 3 hours in the oven (60°C). The dried pulp and peel were ground and sieved using a 60 µm mesh. In this research, chemical and physic-chemical analyses were performed according to AACC (Approved Methods of the American Association of Cereal Chemists) and standard food analysis methods. Textural characteristic was analyzed by a texture analyzer (Brookfield CT3-10 Kg, US) equipped with an aluminum probe. Results: Different levels of APE and APU powders (10, 20, and 30 %) were used to enrich the cakes. Wheat flour’s ash, fat, water, and oil absorption capacity were lower than APU and APE, whereas the moisture, protein, bulk density, and pH showed a reverse trend. Adding APU and APP to the cake formula increased total dietary fiber (TDF) from 4.14 % in the control sample to 27.71 % in the sample with 30 % apple peel powder (APE-30). The highest a* colorimetric parameter (redness) in the cake core was 3.82 in the APE-30 sample. The addition of APE and APU significantly increased the hardness, gumminess, and chewiness of the samples (p<0.05). APE-10 samples could improve the nutritional properties of the cakes without significant reduction (p>0.05) in overall acceptance compared to the control sample. Conclusion: The results of this research demonstrated that a partial replacement of wheat flour with apple pulp and peel significantly increased the dietary fiber, especially insoluble fiber, compared to the control sample. Apple pulp powder and apple peel powder have the potential for use in cake making as a good source of dietary fiber.

Food waste quantities and composition in Polish households.

Over one-third of the produced food is wasted globally. Most food is wasted at the consumer stage. The use of waste sorting analysis is considered to deliver more precise and less biased results than self-reporting methodologies. Currently, no detailed studies on the amounts and composition of household food waste are available for Poland. In the current paper the results of a food waste generation study in the city of Opole in Poland are presented. Both the residual and biowaste from 1425 citizens living in three different city areas was analysed during five seasonal waste sorting campaigns. The food waste was sorted in 16 avoidable and four non-avoidable fractions. The results of this study showed that in the city of Opole the absolute amount of both the avoidable and non-avoidable food waste is higher in the mixed waste stream than in the biowaste (42.8 kg inh.-1 in the residual waste and 19 kg inh.-1 in the biowaste, yearly). Thus, the total segregation level of food waste constitutes at the moment only 31%. The four main categories of avoidable food waste in the mixed waste are: bread (23.9%), vegetables (23.3%), meat (15.1%) and potatoes (7.8%). For the biowaste, the main four categories include: fruits (35.5%), other vegetables (27.9%), meal leftovers (13.6%) and bread (8.6%). Thus the overall food waste generation is 61.7 kg inh.-1 year-1. When also considering alternative discarding routes (sewerage, fed to animals or home-composted), the total food wastage in Opole amounts to 79.9 kg inh.-1 year-1, out of which 37.1 kg inh.-1 year-1 is avoidable waste and 42.8 kg inh.-1 year-1 non-avoidable waste.

Impacts of garbage classification and disposal on the occurrence of pharmaceutical and personal care products in municipal solid waste leachates: A case study in Shanghai

Leachate generated during the treatment and disposal of municipal solid wastes (MSWs) can be an important source of pharmaceutical and personal care products (PPCPs) in the environment. With the implementation of garbage classification policy in China, the disposal methods of MSWs have changed, while its impacts on the occurrence of PPCPs in the generated leachate remain unknown. In this study, we investigated 49 target PPCPs in the leachates of classified MSWs, i.e. residual waste leachate (RWL) and food waste leachate (FWL), and revealed the influence of garbage classification implementation on the occurrence of PPCPs in leachates to be treated. The results showed the concentration and mass load of target PPCPs in the RWL samples (median values: 34.9 ng/L and 52.3 mg/d, respectively) were significantly higher than those in the FWL samples (median values: 19.3 ng/L and 14.5 mg/d, respectively). Macrolide (ML) antibiotics were the predominant PPCPs in the RWL samples, while in the FWL samples, quinolone (QL) antibiotics exhibited the highest concentration and mass load. The implementation of garbage classification policy led to the reduction of PPCP mass load (from 739 g/d to 262 g/d) in leachates to be treated. The findings are helpful for better designing or managing MSW treatment and disposal processes to minimize the emission of PPCPs from MSW leachates.

Litter on the streets - solid waste detection using VHR images

ABSTRACT Failures in urban areas’ solid waste management lead to clandestine garbage dumping and pollution. This affects sanitation and public human hygiene, deteriorates quality of life, and contributes to deprivation. This study aimed to test a combination of machine learning, high-resolution earth observation and GIS data to detect diverse categories of residual waste on the streets, such as sacks and construction debris. We conceptualised five different classes of solid waste from image interpretation: “Sure”, “Half-sure”, “Not-sure”, “Dispersed”, and “Non-garbage”. We tested a combination of k-means-based segmentation and supervised random forest to investigate the capabilities of automatic classification of these waste classes. The model can detect the presence of solid waste on the streets and achieved an accuracy of up from 73.95%–95.76% for the class “Sure”. Moreover, a building extraction using an EfficientNet deep-learning-based semantic segmentation allowed masking the rooftops. This improved the accuracy of the classes “Sure” and “Non-garbage”. The systematic evaluation of all parameters considered in this model provides a robust and reliable method of solid waste detection for decision-makers. These results highlight areas where insufficient waste management affects the citizens of a given city.

Operation and Thermodynamic Modeling of a Novel Advanced Hydrothermal Reactor: Introduction of the Novel 3-Step Evolution Model

Liquid biowaste represents more than 98% of the total municipal waste streams on wet basis and 4–5% on dry basis. Recent attention has been focused on how to manage it optimally, and several novel technologies are being developed to valorize it. Among the developing alternatives is a technology that operates continuously by integrating a hydrothermal reactor, a gasifier and condenser to recover hydrochar using any produced gases to power the system. This study introduces the “3-step evolution model” in order to simulate the hydrothermal reactor. The model has been developed in a MATLAB/Cantera environment and calculates the outputs as the products of a series of sub-stoichiometric char-gas reactions. Experiments with chicken manure slurry as feedstock were implemented for the validation of the model. Treatment of 32.16 kg/h of chicken manure produces 4.57 kg/h of hydrochar and 3.45 kg/h of syngas. The 3-step evolution model simulated the correct ratio of solid-to-gas, 57–43% (excluding the liquids). The experimentally measured carbon dioxide is used as a correction factor to calculate all the other parameters that cannot be assessed during the continuous operation of the hydrothermal reactor. The simulated compositions for carbon dioxide and methane were 94–96% and 0.5–0.8%, respectively. The values were close to the experimental results that ranged from 94.7% to 95.6% for the carbon dioxide and from 0.5% to 0.7% for the methane. The model predicts that higher temperatures of operation would increase carbon monoxide composition from 4–5% up to 7–8%.

A pilot-scale experimental study on MILD combustion of sawdust and residual char solid waste blend using low-temperature preheating air

The treatment of solid waste through incineration has become an important development trend. A solid waste blend (sawdust and residual char) is studied experimentally in a tubular-furnace reactor and a 200-kW pilot-scale furnace under moderate or intense low-oxygen dilution (MILD) combustion conditions. The effects of temperature and oxygen concentration on NO release characteristics are examined in the tubular-furnace reactor. The pilot-scale furnace experiments include the conventional flame combustion using a swirl nozzle (CFC-S), MILD combustion using symmetrical dual straight nozzles (MILDC-SD), and MILD combustion using an asymmetrical single straight nozzle (MILDC-AS). The tubular-furnace reactor results indicate that the NO released from solid waste blend mainly originates from fuel-NO under medium temperature and low oxygen environments. The pilot-scale furnace results demonstrate that stable combustion of the solid waste blend can be achieved under three co-combustion conditions. Compared to CFC-S, the MILDC-AS combustion of solid waste blend inhibits the fuel-NO and PM2.5 emissions by 54% and 50%, respectively. The burnout rates of solid waste blend MILD combustion exceed 95%. This study not only extends the fuel adaptability of MILD combustion to solid waste blend, but also proves the suppression influence of MILD combustion on fuel nitrogen and PM2.5 emissions.