Disposal Technology Research Articles

Efficient bio-cementation between silicate tailings and biogenic calcium carbonate: Nano-scale structure and mechanism of the interface

Biogenic calcium carbonate (bio-CaCO3) cementing tailings is an efficient technology to immobilize heavy metals in waste tailings. However, the underlying mechanism of interface cementation has not yet been clearly established, which limits the technological development. In this study, we used advanced techniques, including atomic force microscopy-based Lorentz contact resonance (AFM-LCR) spectroscopy, AFM-based nanoscale infrared (AFM-IR) spectroscopy, and solid-state nuclear magnetic resonance (ssNMR) spectroscopy, to reveal the structural, mechanical, and chemical properties of the interface on the nanoscale. Ureolytic bacteria produced bio-CaCO3 to fill in pore space and to bind cement tailings particles, which prevented the formation of leachate containing heavy metals. After cementation, a strong 40–300 nm thin interface was formed between the taillings and bio-CaCO3 particles. Unlike chemically synthesized CaCO3, bio-CaCO3 is strongly negatively charged, which gives it better adhesion ability. Fourier transform infrared (FTIR), AFM-IR, and 29Si ssNMR spectra indicated that the Si–OH and Si–O–Si groups on the silicate surface were converted to deprotonated silanol groups (≡Si–O-) at a high pH and they formed strong chemical bonds of Si–O–Ca on the interface through a Ca ion bridge. In addition, hydrogen bonding with Si–OH also played a role at the cementation interface. These findings provide the nano-scale interfacial structure and mechanism of bio-CaCO3 cementing silicate tailings and accelerate the development of tailings disposal technology.

Preheating pyrolysis-char combustion characteristics and kinetic analysis of ultra-low calorific value coal gangue: Thermogravimetric study

A massive amount of coal gangue is produced during the mining and washing processes of coal, and it has become China's largest solid waste. Therefore, the disposal of coal gangue is extremely urgent. In this paper, a norvel coal gangue disposal technology is proposed, which is mainly divided into two stages: high temperature preheating pyrolysis and char combustion. A 300,000 tons/year demostration project of self-sustainable direct combustion decarbonization without auxiliary fuel is eatablished. The weight loss characteristics and kinetic analysis of ultra-low calorific value coal gangue in this process were studied by thermogravimetric analysis, compared with the normal calorific value coal gangue. The results show that the equipment has advantages and stability for the disposal of ultra-low calorific value coal gangue, and the removal rate of combustible components can reach 88.47 % on average. Based on analysis of TG data, it is determined that the best model describing stage 1, stage 2 and stage 3 of coal gangue pyrolysis process is D3, F2 and F2 model respectively, and the best model describing char combustion process is D2 model. Comparison experiments were carried out for ultra-low caloric value coal gangue under different heating rates and combustion temperatures. It is concluded that the residence time and combustion temperature in actual engineering have influence on the process, and it is suggested that the combustion temperature of char should be 800 ∼ 900 ℃. The research presented in this paper can provide innovative solutions for the disposal of coal gangue, and provide corresponding theoretical guidance.

Comprehensive Evaluation of Hazardous Solid Waste Treatment and Disposal Technologies by a New Integrated AHP&MARCOS Approach

Hazardous waste management (HWM) deals with processing waste materials, and improper handling of this procedure might considerably harm human health and environment. It is crucial to employ the most appropriate treatment and disposal techniques while handling with waste materials as part of hazardous waste management so that potential problems can be minimized accordingly. Therefore, the weights of the criteria playing vital roles in solid waste management were determined by using AHP&MARCOS method, which is an integrated MCDM technique, and the most appropriate techniques to be employed in solid waste treatment and disposal were selected. The implementation took place in three phases; the first phase included brainstorming and literature review and the determination of the important criteria in the waste management (4 main and 12 sub-criteria) as well as the treatment (3) and disposal (7) methods to be employed; i.e, the alternatives. In addition, a decision-making group of 15 people was formed so that they could share their opinions based on their knowledge and experiences via the decision matrices while evaluating the alternatives according to the predetermined criteria. In the second phase, the decision matrices constructed based on the expert opinions were taken into consideration while determining weights/priorities of waste management criteria by employing AHP method. In the third phase, treatment and disposal methods were listed by using the decision matrices filled according to expert opinions, the weight values and the criteria. The criteria weights obtained by using AHP method revealed that “operation cost” was the criteria with the highest weight of importance while determining solid waste treatment/disposal methods. Similarly, among the obtained alternatives, the best solid waste treatment technique was found to be “physical treatment” and the best solid disposal technique “plasma arc”. The present study is different from similar studies in the literature since the selection of treatment and disposal method was performed separately for all hazardous solid wastes (healthcare waste, municipality solid waste, etc.) for the first time. Moreover, the obtained results were evaluated by undertaking comprehensive analyses (sensitivity and comparison). The findings obtained in the present study are expected to make valuable contributions to the literature.

Comprehensive study of recycling municipal solid waste incineration fly ash in lightweight aggregate with bloating agent: Effects of water washing and bloating mechanism

Recycling into lightweight aggregate (LWA) by sintering is a promising technology for disposal of municipal solid waste incineration fly ash (FA). In this study, FA and washed FA (WFA) were combined with bentonite and SiC (bloating agent) to make LWA. The performance was comprehensively studied by hot-stage microscopy and laboratory preparation experiments. Water washing and increased FA/WFA improved LWA bloating extent, while shorten the bloating temperature range. Water washing also increased the 1 h-water absorption rate of LWA, making it harder to meet the standard. Excessive FA /WFA usage (70 wt%) will prevent LWA from bloating. For the goal of recycling more FA, mixture with 50 wt% WFA could prepare LWA that meet standard GB/T 17431 at 1140–1160 °C. After water washing, the ratio of Pb, Cd, Zn, and Cu stabilized in LWA increased by 279 %, 410 %, 458 %, and 109 % for 30 wt% FA/WFA addition, and 364 %, 554 %, 717 %, and 697 % for 50 wt% FA/WFA addition, respectively. The change of liquid phase content and viscosity at high temperature were determined using the thermodynamic calculations and chemical compositions. The bloating mechanism was further investigated by integrating these two properties. To obtain accurate results of the bloat viscosity range (2.75–4.44 log Pa·s) for high CaO systems, the composition of the liquid phase should be taken into account. The liquid phase viscosity required for bloating start was proportional to the liquid phase content. With temperature increasing, bloating would end when viscosity drops to 2.75 log Pa·s or liquid phase content reach 95 %. These findings provided further understanding of the heavy metal stabilization during LWA production and the bloating mechanism of high CaO content systems, and could contribute to the feasibility and sustainability of recycling FA and other CaO-rich solid wastes into LWA.

Technology for solid household waste disposal in operating salt mines

Technology for solid household waste disposal in operating salt mines

Theory, framework, and methodology for physical lifespan prediction of hazardous waste landfills

Landfill is a predominant method for hazardous waste disposal in both developed and emerging economies due to simple disposal technology and wide applicability. The prediction of landfill lifespan during the design stage provides support for environmental management of hazardous waste landfill (HWL) and technical support for the implementation of national standards. It also provides guidance for necessary responses after the lifespan expires. At present, research on the degradation of main components or materials of HWLs has been paid much attention, however, how to predict the lifespan of HWLs is a big issue for researchers. In this study, the HWL was selected as research subject, and literature research, theoretical analysis, and model calculation, were used to establish a HWL lifespan prediction framework for the first time. Firstly, the HWL life was defined based on the functional characteristics; secondly, according to comprehensively analyzing the functional requirements, system composition, and structural characteristics of HWLs, the indicators of life termination and the thresholds were confirmed. Then, according to Failure Mode, Mechanism, and Effect Analysis (FMMEA), the failure modes of the core components affecting the lifespan of the HWLs were identified. Finally, a process simulation method (Hydrologic Evaluation of Landfill Performance, HELP) was proposed to simulate the performance degradation of the HWL, combined with the core performance parameters variation caused by the deterioration of the main functional unit. The life prediction framework was developed to increase the prediction accuracy of the performance degradation of HWLs and to provide a methodology for further research on HWL life prediction.

CURRENT TRENDS OF SUSTAINABLE ECOLOGIZATION OF THE TOURISM INDUSTRY IN THE CHERKASY REGION

The article presents an analysis of modern trends in sustainable ecologization of the tourism industry in the Cherkasy region. Tourism is not only one of the factors of economic growth and development of recreational areas, but also an important factor in environmental problems due to irrational use of nature, negative impact on the environment, which determines the urgency of ecologization of the tourism industry at the current stage of tourism industry development. The relevance of the study is explained by insufficient coverage of the issue of ecologization of the tourism industry in the Cherkasy region in the scientific literature. All historical and cultural reserves of the region are quite far from the city of Cherkasy and are located in a picturesque area rich in natural recreational resources, which leads to the active development of tourism there, but this does not always have a positive effect on the environment. The study reveals the prospects for reducing and avoiding the negative consequences of tourism for the environment in the long run with the help of better coordination and preventive planning, environmentally friendly transport concepts, the use of environmentally compatible supply and disposal technologies and careful management of the tourism organizations activities. The article proves that today in Ukraine there is a quite acute problem of determining the needs for the sustainable development of various types of tourism depending on the availability of natural, anthropogenic and natural-anthropogenic tourism resources in various regions of the country, and in the Cherkasy region in particular, as well as the preservation of these resources, since the impact of tourism on the environment is global and irrational use of resources can lead to irreversible consequences. It is expedient to build a strategy for the development of ecological tourism with the help of the relevant authorities of nature conservation areas and the state tourism administration and with the support of national and regional administrations. The concept of sustainable development of tourism should be aimed at promoting the development of settlements and at the same time protecting natural resources. One of the means of preserving the environment can be the allocation of quiet zones according to ecological aspects, in which tourist buildings should be avoided, and pristine natural areas and landscapes preserved.

Integrated LCA and DEA approach for circular economy-driven performance evaluation of wind turbine end-of-life treatment options

The purpose of this paper is to present an integrated joint application of Life Cycle Analysis (LCA) and Data Envelopment Analysis (DEA) in order to evaluate the efficiency of different end-of-life treatment options for wind turbine decommissioning, considering, technological, economic, and environmental aspects in a circular economy context. Eleven scenarios have been configurated concerning the material waste management of a representative type of wind turbine operating in Greece. Mechanical recycling, landfill disposal and advanced thermal recycling technologies, such as conventional or microwave pyrolysis are addressed. The proposed approach does not only evaluate the efficiency of each one of the different end-of-life treatment processes relative to one another, but it also suggests circular economy-driven policy-making scenarios towards more sustainable waste management in the country. Real-world data calculations indicate that improving the performance of the energy-intensive thermal recycling process could maximize the environmental benefits. Α circular zero-waste approach based on remanufacturing, repurposing or waste prevention through design-for-recycling of wind turbine blades, could also favor long-term sustainability.

Life cycle assessment of carbon reduction potential of EoL wind turbine blades disposal scenarios in China

It is estimated that there will be 85,000 tons of End-of-Life (EoL) wind turbine blades in China by 2050. How to disposing discarded blades has become a significant problem restricting the development of wind power industry in China. To this end, a life cycle assessment (LCA) is performed to measure the carbon reduction (CR) potential of four disposal scenarios of EoL LM 37.3 P2 blades. The contribution of each scenario to reduce the carbon emission intensity of a specific wind farm is further evaluated. At the same time, the critical transportation distance to maintain the CR potential of each scenario is estimated. The results show that: firstly, the disposal scenarios with the greatest and smallest CR potential are producing concrete by EoL blades instead of cements and producing concrete by EoL blades instead of aggregates, respectively. The former one is determined as the baseline scenario, which can reduce 4516 kg CO2-eq carbon emissions per functional unit. Secondly, the critical transportation distances for incineration for electricity, co-processing and producing concrete by EoL blades instead of cements are 895 km, 3309 km and 9716 km. Finally, a reasonable recycling strategy can reduce the life-cycle carbon emission intensity of Datang Zhaluteqi 49.5 MW Wind Farm from 12.51 g CO2-eq/kWh to 9.22 g CO2-eq/kWh. This study not only quantifies the CR potential of different scenarios, but also offers important implications to promote blade disposal technology and improve the wind turbine blade recycling management.

Reaction pathway and kinetics study on supercritical water gasification of oily sludge

Supercritical water gasification of oily sludge is a clean technology for waste disposal and energy recovery. In this work, gaseous productions from supercritical water gasification (SCWG) of oily sludge in a batch reactor under different temperatures (550–650 °C) and residence times (1–40 min) was studied. Then, a quantitative kinetic model was employed to study the reaction mechanism and optimize the H2 and CH4 productions. The H2 yield was promoted with the increase in temperature and residence time. The CH4 yield and carbon gasification efficiency (CE) increased with the prolongation of residence time, but reached the maximum when the temperature was 600 °C. The liquid products were mainly composed of alkene, acetone, benzene, toluene, ethylbenzene and xylene, phenolic substances and polycyclic aromatic hydrocarbons (PAHs). Higher temperatures promoted the formation of phenol and PAHs in liquid products, which were hard for gasification. The results of kinetic model indicated that higher temperatures accelerated the reaction rate and intermediates formation, but the effect on gas formation was limited. Reaction rate analysis at 650 °C indicated that H2 was mainly produced from pyrolysis rather than steam reforming. CH4 was produced mostly from pyrolysis and methanation reaction can be neglected.

Structural, functional, and physicochemical characterization of fermented whey protein concentrates recovered from various fermented-distilled whey

The utilization of whey has become a challenge with the significant growth in the production of cheese and coagulated milk products. Consequently, we have developed cost-effective and waste-free production technologies for processing whey disposal into a variety of high-quality, value-added food products at the industrial level. This work constitutes a research on the impact of various alcoholic fermentations on functional, structural, and physicochemical properties of fermented whey proteins recovered from whey-based spirit production effluent. The results showed that surface hydrophobicity and sulfhydryl groups of fermented whey protein concentrates (FWPC) increased significantly in comparison with native whey protein concentrate, while the zeta-potential and particle size of non-supplemented FWPC and low-supplemented FWPC were not substantially affected by fermentation. Furthermore, the outcomes indicated that the non-and low-supplemented whey fermentation led to the improvement in the solubility of FWPCs dispersions, and enhancement in the emulsifying activity and stability of FWPCs. Size exclusion chromatography and SDS-Page results also demonstrated significantly increased β-Lg content in FWPCs, which might be attributed to the reinforcement of the β-Lg intramolecular and noncovalent bonds. The enhancement in functionality was probably due to the partially unfolded whey protein molecules, exposing more hydrophobic amino acid residues, thus making the protein more amphiphilic and capable. Nevertheless, high-yield alcoholic fermentation led to critical changes in the structural properties of whey proteins as evidenced by SEM results. Therefore, our findings suggested that the application of recovering FWPCs after producing premium quality potable whey-based spirit from the presence of non-and low-lactose supplemented whey is fully proposed as an industrially recommended alternative for food-grade protein production. • Fermentation process significantly increased general properties of FWPC. • More amphiphilic and capable proteins recovered due to exposed hydrophobic amino acids. • Increased β-Lg content in fermented whey protein leads to better functionality. • FWPC is proposed for manufacturing food-grade protein at the industrial level.

Enhanced degradation of sulfamethoxazole by activation of peroxodisulfate with red mud modified biochar: Synergistic effect between adsorption and nonradical activation

Since the discovery of the potential environmental risk associated with large quantities of red mud, there has been an urgent need to find a rational disposal technology for this waste. In this study, low-cost iron-based biochar catalysts (RM@BC-x) were synthesized by co-pyrolysis of waste red mud and spent coffee grounds after ball milling. RM@BC-800 exhibited remarkable adsorption capacity, reaching 4.70 mg/g in 120 min. The adsorbed SMX was degraded simultaneously after adding peroxodisulfate (PDS), and sulfamethoxazole (SMX) was completely removed from the solution in only 30 min. Correlation analysis and pre-sorption experiment proved that the adsorption of SMX significantly enhanced the oxidation effect. Moreover, the Fe0, defects and CO groups of RM@BC-800 were the main active sites. Singlet oxygen (1O2) played a dominant role in the degradation of SMX rather than the traditional radicals (•OH or SO4•−). In particular, O2•− was shown to be used mainly as a precursor for the production of 1O2 without directly oxidizing SMX. The steady state concentration of 1O2 has been calculated to be hundreds or thousands of times higher than that of other radicals. Five degradation pathways of SMX were proposed (including NS bond cleavage, hydroxylation, and –NH2 oxidation). RM@BC-800 has the advantages of strong anti-interference ability, low iron leaching based on energy calculations and environmental impact assessments. This work provides a new option for the resource utilization of red mud and designs a green material with fast adsorption and efficient catalysis for the practical treatment of antibiotic wastewater.

Self-powered wastewater purification and phosphorus recovery systems with novel self-filtering Al-air batteries

Sustainable water treatment systems are crucial for water recycling and resource recovery. However, the existing self-powered water treatment technology for metal-air batteries has several challenges. This study proposed a new self-powered water treatment system concept by developing self-filtering aluminum-air (SF Al-air) batteries. The sandwich-shaped flexible air cell comprised an aluminum (Al) scrap anode, an inexpensive hydrophilic separator, and a graphite-coated titanium mesh cathode. By utilizing the capillary action and porous structure of the separator, the autonomous flow and filtration of electrolytes or wastewater were achieved inside the battery. Owing to the high Al purity of 95 % and the ultra-thin structure, the low-cost kitchen Al foil is a promising anode, with the highest power density of 23.02 mW g−1 (anode weight), 4.60 × 10−2 W $−1 (anode cost). Kitchen paper is the preferred separator facilitating electrolyte transfer and automatic renewal inside the battery owing to the strong water storage property. The SF Al-air cell can also efficiently removed 90% of phosphorus at an initial concentration of 100 mg P/L and initial pH = 7. Specifically, the cell converted phosphate pollutants and Al foil waste into a valuable AlPO4·2H2O flame retardant coating on kitchen paper, resulting in a first-class flame retardancy of the separators. Lake water treatment results showed that the self-powered SF-Al-air cell purified real surface water and obtained a stable power production of 146.7 mW g−1. Our study demonstrates a promising sustainable water treatment technology for simultaneous power generation, wastewater purification, phosphorus recovery, and waste Al disposal.

Development and Research of Recyclable Composite Metamaterial Structures Made of Plastic and Rubber Waste to Reduce Indoor Noise and Reverberation

According to the Waste Management Policy of the European Union, the recycling and reuse of various wastes is considered the most ecological and advanced waste disposal technology with the lowest impact on the environment. By applying circular economy principles, plastic waste will extend its life cycle and be used as secondary raw materials to create structures with good sound insulation and absorption properties. Structures created from metamaterial with plastic were studied for their sound-absorbing properties in an impedance tube. A combined 100 mm long resonator design with a 2.0 mm perforation, 20 mm thick plate, regardless of whether it is an “X”- or “O”-shaped resonator, achieved a good sound absorption peak at 315 Hz of 0.94. When the combined structures of 50 mm long “X”- and “O”-shaped designs were compared, different sound absorption peaks at high frequencies were achieved. A slightly better sound absorption peak of 0.95 was achieved at 500 Hz with the “O”-shaped resonator and 0.93 at 630 Hz with the “X”-shaped resonator. The results show that the combined plastic and rubber structures can be integrated into building structures and be used as an alternative to improve building acoustics and reduce noise and reverberation.

Energy Utilization Assessment of Municipal Sewage Sludge Based on SWOT-FAHP Analysis

Recently, due to the abundance of carbon, nitrogen and phosphorus in municipal sewage sludge (MSS), the energy potential of MSS has become increasingly prominent. Economically developed regions possess more financial and policy support advantages for the development of MSS energy recovery technology; hence, the selection of the appropriate sludge treatment and disposal technologies to maximize the energy potential of MSS is of great importance. In this study, the energy recovery potential of MSS was evaluated on the basis of regional economies, sludge analysis, a main sludge energy reuse technology review and legislative profile analysis. As the most commonly adopted technology, incineration had a lower energy potential, which may be ascribed to the high moisture content, high disposal costs and difficulties in in situ energy recovery. In contrast, the energy potential for anaerobic digestion, pyrolysis and gasification was relatively high. By conducting a SWOT-FAHP analysis, management evaluation of these four technologies was carried out from the following four perspectives: problem solving, technology development, ecological environment and laws and regulations. Pyrolysis was evaluated to be the most suitable technology from the technical and environmental perspectives because its products had high energy potential and avoided heavy metal problems. The obstacles and problems that pyrolysis technology might encounter in commercial applications in the future are discussed. With this energy-generating, low energy consumption, low-pollution sludge energy reuse technology, the potential of sludge pyrolysis would be high in the long run. These results revealed the factors affecting the energy recovery potential of sludge, and comprehensively evaluated the technologies from the aspects of problem solving, environmental impact, technology development and law, the optimal solution obtained could provide reference on the management decision of sludge disposal technology for economically developed areas in the future.

DISPOSAL OF MANURE AT THE PIGGERY USING BIODESTRUCTORS OF DIFFERENT ORIGIN

The development of biotechnological methods of disposal of pig waste products is relevant at the current stage. However, the high cost of investment and operation of such technologies limits their application. Therefore, owners of pig farms are constantly looking for compromise solutions that would, on the one hand, ensure compliance with technological requirements for manure removal, and on the other hand, not pollute the environment. The purpose of the work is to improve existing technologies and develop innovative approaches to biotechnological methods of manure disposal. Scientific research was carried out at the piggery of Agroprime Holding LLC of the Odesa region with a capacity of 30,000 heads per year. The considered technology of using biological preparations De-Scentase and Complesin for descentization of manure in underground baths, manure storages, manure sites of the complex. The content of gases in the manure subfloor bath of the piggery due to the use of biological preparations was determined. The conducted monitoring of unpleasant scents and harmful gases confirmed the expediency of using new methods of neutralizing unpleasant scents. It was established that the reconstruction of the separator station by installing a metal hangar and a water-dispersion filtration chamber ensured the neutralization and release of scentous gases into the environment and did not affect the ecological state of the environment negatively. On the basis of the conducted research, the method of wide application of the biological preparation for the disposal of manure has been developed. The improved technology of manure disposal at the piggery, which involves the addition of the microbial destructor drug Complesin to underground baths, as well as to manure storages and manure sites, helps to reduce the release of harmful gases and accelerates the disposal of manure. The technology of utilization of liquid and solid fraction of manure by using biological preparation and vermiculture is highlighted. The experience of using equipment for underground application of liquid manure to fields is presented.

ECOLOGICAL JUSTIFICATION OF WASTE-FREE TECHNOLOGIES FOR URBAN WASTEWATER DISPOSAL

The article deals with the issues of waste-free technology of wastewater disposal. Analysis of information on water quality and the state of the ecosystem of Kazakhstan's water bodies shows that most of them are unable to perform their main function – to maintain the geosystem structure formed as a result of prolonged anthropogenic human activity. The reason for the current environmental situation is the management of the economy in accordance with the previously adopted and practically valid technocratic concept of economic development, which does not actually include the thesis of taking into account possible negative consequences for the environment as a result of extensive consumption of resources. In this regard, the consequence for the water resources of Kazakhstan was the loss of water content and the formation of polluted wastewater, the discharge of which has become the norm in the practice of modern wastewater disposal. The ever-increasing flow of pollution, which includes more and more new ingredients, leads to a change in the intensity and direction of the water-body processes in the drainless basins of Kazakhstan. As a result of economic activity, foci of secondary pollution with completely unpredictable properties were formed, which are included in the scope of action of intra-reservoir processes. Currently, scientists are persistently searching for specific innovations or technological schemes for the functioning of enterprises or industrial complex, which will significantly reduce and completely eliminate emissions of harmful anthropogenic substances. In this regard, engineering developments of closed and semi-closed technological cycles, circular water supply systems of enterprises, technical systems with low water and energy consumption, low-waste and non-waste technologies for waste disposal of urban and industrial facilities are considered the most promising

Advances in Waste Plastic Disposal and Utilization Technology

Advances in Waste Plastic Disposal and Utilization Technology

Research on residual sludge disposal and resource utilization technology of urban sewage treatment plant

Urban sewage treatment plants play a pivotal role in the process of urban sewage treatment in China, but due to the implementation of the daily urban sewage treatment process will appear a large number of residual sludge, if not timely and properly disposed of, it will affect the surrounding natural environment, and even endanger human health. Therefore, taking effective measures, such as reasonable treatment of sludge, can efficiently convert waste into resources and achieve efficient use of resources. This paper aims to deeply explore the most commonly used sludge treatment technologies, and compare and analyze the advantages and disadvantages of various technologies, in order to provide useful suggestions and references for environmental protection and engineering applications.

Implementation of poultry waste disposal technology for energy and fertilizer production

The developed unit, which implements the technology of separation of raw materials into useful components by thermal destruction, makes it possible to obtain fuel synthesis gas, in which carbon monoxide (CO) and hydrogen (H2) predominate, suitable for use in internal combustion generators for generating electrical energy, as well as saturated ash potassium (K) and phosphorus (P) suitable as a fertilizer in agriculture.