Power Plant Waste Research Articles

An Azo-Group-Functionalized Porous Aromatic Framework for Achieving Highly Efficient Capture of Iodine.

The strong radioactivity of iodine compounds derived from nuclear power plant wastes has motivated the development of highly efficient adsorbents. Porous aromatic frameworks (PAFs) have attracted much attention due to their low density and diverse structure. In this work, an azo group containing PAF solid, denoted as LNU-58, was prepared through Suzuki polymerization of tris-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl)-amine and 3,5-dibromoazobenzene building monomers. Based on the specific polarity properities of the azo groups, the electron-rich aromatic fragments in the hierarchical architecture efficiently capture iodine molecules with an adsorption capacity of 3533.11 mg g−1 (353 wt%) for gaseous iodine and 903.6 mg g−1 (90 wt%) for dissolved iodine. The iodine uptake per specific surface area up to 8.55 wt% m−2 g−1 achieves the highest level among all porous adsorbents. This work illustrates the successful preparation of a new type of porous adsorbent that is expected to be applied in the field of practical iodine adsorption.

Impact of Silica Fume on Fly Ash Based Concrete Material

Fly ash, being a by-product, discarded and dumped as the power plant waste, is found to be highly toxic with its pozzolanic property. It can be utilised as a construction material to substitute cement. Along with fly ash, additional waste materials such as silica fume and rice husk have diversified applications to enhance the strength of the concrete material. In the present study, concretes are being prepared using variable combinations of fly ash, silica fume and rice husk dust, and their physical and mechanical properties are studied extensively. It is being observed that the addition of silica fume alone in the fly ash could produce concrete blocks with a compressive strength of 35 MPa whereas when silica fume is added along with rice husk powder, the compressive strength could be raised up to 40 MPa. Both types of concrete blocks are subjected to curing period of 14 days to 21 days. The result revealed that block containing silica fume shows corrosion resistance property, whereas blocks containing a combination of rice husk dust and silica fume shows both the property of hydrophobicity as well as corrosion resistivity. The study summarised the fact that by exploring the chemical and mechanical properties of some of the waste material, it is possible to prepare a hydrophobic, corrosion resistance block that could replace the use of cement in the concrete and contribute maximum to get rid of environmental pollutions.

Optimasi Proses Gasifikasi Menggunakan Logika Fuzzy Mamdani

This study aims to test the performance of fuzzy logic in the gasification process. Gasification is the process of converting solids into flammable gases. The gas produced becomes an alternative energy source, namely the Waste Power Plant (PLTSa). The research applies Mamdani's Fuzzy logic. Fuzzy logic was created using Matlab R2018b software. The results obtained indicate that the Mean Absolute Error (MAE) output of H2 on fuzzy logic training data is 6.57. The test results for CO fuzzy output MAE value of 1.12. The test results on CO2 MAE fuzzy are 1.18. In the CH4 test, the MAE fuzzy output is 0,84.

How bitcoin makes burning fossil fuels more profitable than ever

ABSTRACT Bitcoin mining is a lucrative but energy-intensive activity. To keep costs low, miners are finding new ways to make their own electricity, often derived from fossil fuels. Mining companies are buying struggling coal, coal waste, and gas power plants and using the electricity they generate for their mining operations. Existing utility companies and power plants are pivoting to mining to make up for declining demand. Oil and gas companies are also buying mobile generators and installing them at well sites, mining right there at the oil or gas well, or selling the gas to third-party miners. The fossil fuel-to-bitcoin pipeline is getting shorter and shorter, and associated greenhouse gas emissions are climbing.

Nuclear Energy Contribution for Net Zero Emission and National Energy Mix 2060 in Indonesia

Indonesian Government has strongly announcement to the public which is in line with the Paris Agreement that has been signed and ratified with other 164 countries across the globe to fulfil their commitment to reduce the greenhouse gas effect. In 2060, the estimated total demand market of about 1800 TWh which is consist of about 300 TWh of electric demand in the present status which will be required additional new energy supply of about 1500 TWh. This new additional energy which is about five times larger than the present energy which leads to more energy resources and alternative energy supplies are required. Meanwhile, fossil fuels as main producer will be reduced and NRE will be utilized more, and it is increased gradually to maintain the energy demand as well as reducing the CO2 emission to the net zero target. In the present study, the contribution of each energy resources especially for the contribution of nuclear power plant (NPP) will be evaluated as a part of national energy mix. The evaluation of nuclear energy contribution is needed to estimate the electricity contribution level as well as the contribution to reduce the CO2 emission and it will compare to other energy resources as comparable analysis. Nuclear power plant requires the lowest install capacity of 211 GWe followed by waste power plant, geothermal and the highest installed capacity was solar PV power plant which requires 765 GWe to produce 1500 TWh electricity for a single 100% power plant. It can be seen the reduction GHG from more than 1300 Mton GHG release from coal can be reduce significantly by NRE of about more than 95% of reduction factor. Total electric contributions based on all energy mix, and it shows nuclear energy contributes 247 TWh (16,5 %) in total 1500 TWh.

Assessing the roles emission sources and atmospheric processes play in simulating <i>δ</i><sup>15</sup>N of atmospheric NO<sub><i>x</i></sub> and NO<sub>3</sub><sup>−</sup> using CMAQ (version 5.2.1) and SMOKE (version 4.6)

Abstract. Nitrogen oxides (NOx= nitric oxide (NO) + nitrogen dioxide (NO2)) are important trace gases that affect atmospheric chemistry, air quality, and climate. Contemporary development of NOx emissions inventories is limited by the understanding of the roles of vegetation (net NOx source or net sink), vehicle emissions from gasoline- and diesel-powered vehicles, the application of NOx emission control technologies, and accurate verification techniques. The nitrogen stable isotope composition (δ15N) of NOx is an effective tool to evaluate the accuracy of the NOx emission inventories, which are based on different assumptions. In this study, we traced the changes in δ15N values of NOx along the “journey” of atmospheric NOx, driven by atmospheric processes after different sources emit NOx into the atmosphere. The 15N was incorporated into the emission input dataset, generated from the US EPA trace gas emission model SMOKE (Sparse Matrix Operator Kernel Emissions). Then the 15N-incorporated emission input dataset was used to run the CMAQ (Community Multiscale Air Quality) modeling system. By enhancing NOx deposition, we simulated the expected δ15N of NO3-, assuming no isotope fractionation during chemical conversion or deposition. The simulated spatiotemporal patterns in NOx isotopic composition for both SMOKE outputs (simulations under the “emission only” scenario) and CMAQ outputs (simulations under the “emission + transport + enhanced NOx loss” scenario) were compared with corresponding measurements in West Lafayette, Indiana, USA. The simulations under the emission + transport + enhanced NOx loss scenario were also compared to δ15N of NO3- at NADP (National Atmospheric Deposition Program) sites. The results indicate the potential underestimation of emissions from soil, livestock waste, off-road vehicles, and natural-gas power plants and the potential overestimation of emissions from on-road vehicles and coal-fired power plants, if only considering the difference in NOx isotopic composition for different emission sources. After considering the mixing, dispersion, transport, and deposition of NOx emission from different sources, the estimation of atmospheric δ15N(NOx) shows better agreement (by ∼ 3 ‰) with observations.

Overview on the management of radioactive waste from fusion facilities: ITER, demonstration machines and power plants

In the absence of official standards and guidelines for nuclear fusion plants, fusion designers adopted, as far as possible, well-established standards for fission-based nuclear power plants (NPPs). This often implies interpretation and/or extrapolation, due to differences in structures, systems and components, materials, safety mitigation systems, risks, etc. This approach could result in the consideration of overconservative measures that might lead to an increase in cost and complexity with limited or negligible improvements. One important topic is the generation of radioactive waste in fusion power plants. Fusion waste is significantly different to fission NPP waste, i.e. the quantity of fusion waste is much larger. However, it mostly comprises low-level waste (LLW) and intermediate level waste (ILW). Notably, the waste does not contain many long-lived isotopes, mainly tritium and other activation isotopes but no-transuranic elements. An important benefit of fusion employing reduced-activation materials is the lower decay heat removal and rapid radioactivity decay overall. The dominant fusion wastes are primarily composed of structural materials, such as different types of steel, including reduced activation ferritic martensitic steels, such as EUROFER97 and F82H, AISI 316L, bainitic, and JK2LB. The relevant long-lived radioisotopes come from alloying elements, such as niobium, molybdenum, nickel, carbon, nitrogen, copper and aluminum and also from uncontrolled impurities (of the same elements, but also, e.g. of potassium and cobalt). After irradiation, these isotopes might preclude disposal in LLW repositories. Fusion power should be able to avoid creating high-level waste, while the volume of fusion ILW and LLW will be significant, both in terms of pure volume and volume per unit of electricity produced. Thus, efforts to recycle and clear are essential to support fusion deployment, reclaim resources (through less ore mining) and minimize the radwaste burden for future generations.

Mixed-Integer Linear Programming for Decentralized Multi-Carrier Optimal Energy Management of a Micro-Grid

Increasing the load demand and penetration of renewable energy sources (RESs) poses real challenges for optimal energy management of distribution networks. Moreover, considering multi-carrier energy systems has increased the efficiency of systems, and provides an opportunity for using the advantages of RESs. In this regard, we adopted a new framework based on the new challenges in the multi-carrier energy micro-grid (MEMG). In the proposed method, a comprehensive MEMG was modeled that benefits from a large assortment of distributed energy resources (DERs), such as micro-turbines, fuel cells, wind turbines, and energy storage. Considering many DERs is necessary, because these resources could cover one another’s disadvantages, which have a great impact on the total cost of the MEMG and decrease the emission impacts of fossil-fuel-based units. Furthermore, waste power plants, inverters, rectifiers, and emission constraints are considered in the proposed method for modeling a practical MEMG. Additionally, for modeling the uncertainty of stochastic parameters, a model based on a multilayer neural network was used in this paper. The results of this study indicate that using a decentralized model, along with stochastic methods for predicting uncertainty, can reduce operational costs in micro-grids and computational complexity compared with optimal centralized programming methods. Finally, the equations and results obtained from the proposed method were evaluated by experiments.

Desulphurization of FGD wastewater through bacterial sulfate reduction process with agricultural incineration bottom ash as an amendment

Coal-fired power plants produce a large amount of sulfate-laden flue gas desulphurization (FGD) wastewater, while a sustainable amount of incineration ash was produced as solid waste in biomass power plants. Both FGD wastewater and incineration ash led to serious environmental problems without proper treatment. Sulfate reduction was an efficient technology for FGD wastewater treatment, however, the carbon source was insufficient for reducing sulfate in FGD wastewater which needed to be replenished. In this study, pyrolyzed incineration bottom ash (PIA) was introduced to sulfate reducers for FGD wastewater treatment. Sulfate-reducing activity increased (up to 2.9-fold) with PIA300 (incineration ash pyrolyzed under 300 °C) addition. Remarkably increasing abundance of Clostridium (12-fold) and Paraclostridium sp. (79-fold) bacteria were observed in sulfate-reducing sludge with PIA300 addition. Pyrolyzed incineration ash not only acted as a carrier for sulfate reducers, but also provided additional carbon, alkalinity and trace elements (Fe, K, Ca, etc.) for sulfate reduction. Incineration ash was partially degraded by sulfate-reducing bacteria (up to 39.4%), meanwhile, heavy metals (Mg, Al, Cr, Co, Ni, Cu, Zn, etc.) leached from ash and existed in FGD wastewater were efficiently co-removed (95–100%). Addition of PIA to sulfate reducers led to increased formation of extracellular polymeric substances, which might enhance the biotransformation and degradation of organic matters in both ash and FGD wastewater. Thus, a promising FGD wastewater treatment technology was established in this study, to achieve simultaneous FGD wastewater reclaim and solid waste utilization.

Photocatalytic Degradation of Reactive Dyes Using Flyash Supported Ag‐TiO2 Photocatalysts

AbstractIn the present study, photocatalytic degradation of five different reactive dyes has been carried out using Ag doped TiO2 supported on coal fly ash (CFA) as a photo catalyst system (Ag‐TiO2/CFA). The photocatalysts were synthesized with varying the percentage of Ag and characterized by XRD, SEM and UV‐visible spectrophotometry. The photocatalytic activity of Ag‐TiO2/CFA photocatalysts was studied for the degradation of reactive dyes in presence of both UV and visible light sources. The degradation was monitored by absorbance measurements. It was found that 3 wt % of Ag doping could bring about maximum degradation (85–95 %) at 3–4 h in presence of visible light. The effect of various parameters such as initial concentration of dye, catalyst amount and pH of solution towards the degradation were studied and it was observed that in acidic conditions the degradation was maximum (pH=3.0) for all the dyes studied. Ability to degrade an industrial waste, use of CFA, a thermal power plant waste as support, small quantities of silver required and degradation under visible light are the environmental as well as economic advantages of this developed catalytic system.

Assessment of environmental and chemical properties of coal ashes including fly ash and bottom ash, and coal ash concrete

Cement and aggregates are the essential materials for concrete production. Besides, industrial wastes supplant construction materials. Investigating the engineering properties and environmental aspects of concrete produced with waste materials is required. Thus, this study researched leaching, chemical, and physical properties of the coal power plant wastes and concrete containing coal ashes. These wastes included Fly Ash (FA) and Bottom Ash (BA). X-ray fluorescence (XRF), X-Ray diffraction (XRD), and scanning electron microscopy (SEM) revealed the physicochemical traits, toxicity characteristic leaching procedure (TCLP), and semi-dynamic tank leaching procedure (SDTLP) determined the leaching performance. Physicochemical analysis of FA and BA showed that these wastes, by-products can be a part of cement and fine aggregate substitute in concrete production. However, leaching test results did not demonstrate any leaching trace elements and heavy metals to the environment from BA, FA, and coal ash concrete. The FA and BA had the potential as cement and fine aggregate replacements, respectively. Using coal ashes (FA and BA), sustainable and green concrete can be made having advantages, such as reducing the final cost production of concrete and utilizing less natural resources.

ZERO WASTE LIFESTYLE CONCEPT WITHIN ISLAMIC-SCIENCE PRESPECTIVE

Islam has comprehensive rule that regulate in all aspects of human life, including evireonmental issues. One fact of global problems related to environment is waste management problem. Zero waste is waste management system which it could be a holistic solution due to waste issue. This study aim to analyse the zero waste concept within Islamic-science prespective on municipal waste reduction as a solution to prevent environmental damage. This study use literature reviews method that focuse on waste management programs in Surabaya City which have been stated on a national and international scale. The results of this study show implementation of waste management programs In Surabaya City such as the depletion of disposable plastic usage, the existence of waste bank units, until the presence of a solid waste power plant infrastructure. However, the program implementation has not been able to decrease the number of resource in Surabaya landfill. It is because of poorly coordination between government and society, and the lack of environmental awareness about the harm of waste resource to environmental health. Thus, the existence of zero waste concept combined with Islamic-science prespective could lead direction movement to appreciate the importance of proper and correct waste management. Based on these results, it conclude that waste management with zero waste concept considered to become a new lifestyle in waste management namely Islamic lifestyle, because it is in line with Islamic law. Moreover, this new lifestyle could be implemented in all communities regarding to the nature is a gift form Allah SWT and humans have a command to protect it.

Modeling the properties of lightweight polymer concrete produced from polyvinyl chloride and combined heat and power plant waste

Although concrete based on mineral binders is most commonly used in construction, polymer concrete is on the rise lately. This is due to the fact that polymer concrete allows to expand concrete usage in civil and industrial construction thanks to its properties. However, there is extensive research on including thermoplastic polymer. Construction polymer concrete materials have high compressive strength, as well as atmospheric, cold and chemical resistance, thus resulting in long term lifetime. This paper suggests a technological process of producing concrete based on polyvinyl chloride and lightweight porous aggregate, e. g. fly ash that comes from Vladimir combined heat and power plant (used to run on coal). There are up to 80 thousand tons of this aggregate in stock. It turns out that technological parameters of this process are strongly intertwined with compound. Research indicates that lightweight polymer concrete based on polyvinyl chloride and fly ash can be achieved under certain technological parameters. A new polymer concrete was created as a result of this research having the following properties: density - 800-830 kg/m3, compressive strength - 12-13 MPa, impact strength -16-18 kg/m2, coefficient of thermal conductivity - 0.16-0.18 Wt/m.K, frost resistance - at least a 100 cycles.

Framework and Key Success Factors of Governance and Sustainability of Very Small Municipal Solid Waste Power Plants

Inordinate municipal solid waste issues and ever increasing demand for electricity, the Thai government formulated the Power Development Plan focusing on supporting the use of renewable energy to generate electricity and using measures to promote the purchase of electricity from very small power producers. This support indubitably leads to the question as to whether Very Small Municipal Solid Waste Power Plants (VSMSWPPs) are sustainable or not. Thus, this study aims to develop a framework and key success factors for evaluating governance and sustainability of VSMSWPPs in Thailand. It consists of documentary research and interviews with professionals, policy makers, practitioners and power plant owners conducted to develop the framework and determine the key success factors. Subsequently, the framework and factors were assessed by 12 experts. The good governance and sustainability concepts were selected as a framework and used to construct key success factors to evaluate the performance of VSMSWPPs. The framework contains four dimensions and each dimension had key success factors as follows: (1) Governance dimension with 7 key success factors; (2) Economic dimension with 8 key success factors; (3) Social dimension with 5 key success factors; and (4) Environmental dimension with 7 key success factors: at total of 27 key success factors.

Experimental Study on Solidification of Pb2+ in Fly Ash-Based Geopolymers

Fly ash from the incineration of domestic waste contains heavy metals, which is harmful to the environment. To reduce and prevent their contamination, heavy metal ions need to be sequestered. In this study, the geopolymer prepared by fly ash, a kind of power plant waste, is used to cure the heavy metal Pb2+, and to investigate the effect of different concentrations of Pb2+ on the compressive strength of the solidified body at different ages; the curing effect is judged by the toxic leaching concentration of heavy metals; the resistance of the solidified body to immersion is evaluated by comparing the change in strength before and after leaching; the fly ash-based geopolymer solidified body is compared with the cement solidified body in terms of curing effectiveness; the properties of the geopolymer and its mechanism of curing heavy metals are explored by microscopic tests. The results show that the fly ash-based geopolymer solidified body has good resistance to immersion; the optimum curing concentration of Pb2+ in fly ash-based geopolymers is 2.0%; compared to pure geopolymers, the strength of the solidified body at 28 d decreases by only 13.0%, and the leaching concentration of Pb2+ is 4.73 mg·L−1, which meets the specification requirements; the curing effect of the fly ash-based geopolymer is better than the cement solidified body; the microscopic test results indicate that the curing of Pb2+ by the fly ash-based geopolymer is a combination of both chemical bonding and physical fixation.

Study on the Potential of Waste in Pangkalpinang as Source of Power Generation

The Waste Power Plant is one of the power plants with a new renewable energy concept that utilizes waste as fuel. The processing of waste into electrical energy is carried out in two ways: the thermal conversion process and the biological conversion process to find the potential for waste that can be used as fuel to generate electricity. The analysis is needed, especially for Pangkalpinang, which currently has a lot of unprocessed waste. This research was conducted through calculations using several formulas that have been used in previous studies. From these results, the potential waste in 2015 is 97.25 tons/day and produces energy of 18548.10 MWh/year, and in 2020, it was about 186.57 tons/day and produced energy of 35547.18 MWh/year. The projection calculations are carried out to determine the potential for 2021 to 2030. Waste as much as 182523 tons/day in2021 can produce energy of as much as 34776.11 MWh/year. And in 2030, the amount of waste as much as 218132 tons/day can generate an energy potential of 41560.69 MWh/year.

PEMODELAN GENERATOR YANG EFEKTIF YANG DIPASANGKAN DENGAN IMPACT WRENCH SEBAGAIUSAHA UNTUK MENINGKATKAN DAYA PADA PEMBANGKIT LISTRIK TENAGA SAMPAH

The amount of waste can be overcome, some efforts are needed to reduce it. This research will focus on the numerical model of a solid waste power plant. Researchers replace turbine with an impact which have a specification certain pressure, the impact rotates the generator The purpose of this research is to get the rms voltage of a generator, where the generator is a generator capable of supplying a rms voltage. This effort is made to convert waste energy into electrical energy. Generators which are the main topic in this research are synchronous generators and permanent magnet generators. Water with a mass of requires a temperature of to provide the required stress, while water with a mass of , its temperature is Water with a mass of requires a temperature of to provide the required voltage, while water with a mass of has a temperature of . For a water mass of , a temperature of , the synchronous rotor speed is , the rms voltage is . To reach the rms voltage of , the rotor on the generator must rotate at a synchronous speed of .
 
 
 

RANCANG BANGUN PEMBANGKIT LISTRIK TENAGA SAMPAH (PLTSa) DI LINGKUNGAN STT MIGAS BALIKPAPAN

The Environment and Forestry Metrics stated that data on waste piles in Indonesia in 2020 reached 67.8 tons, 45% of which was poorly managed plastic waste. The large amount of waste produced causes Indonesia to become the second waste producer in the world. The level of waste management that is still minimal is the main thing that causes Indonesia to become a "polluting" country in the world. Waste Power Plant is a waste management solution to reduce the amount of waste and become an alternative energy for generating electricity in the community. The purpose of this research is to provide an alternative by creating a waste power plant as a producer of renewable electrical energy. This research begins with collecting materials and continues with the design of components such as furnaces, boilers, steam turbines, DC generators which are integrated into one, and waste as fuel. The components that have been worked are then tested with plastic waste and wood waste are collected and then put into the furnace, then the waste is burned to boil water in the boiler. Changes in the speed or relative velocity of this steam cause a force turns the turbine. The turbine that is connected to this generator will then rotate the generator to produce electricity. Based on the results of testing the solid waste power plant, the maximum voltage value is 13.76 V.

A low-cost photo-evaporation inorganic membrane preparation and treatment of the simulated high salinity radioactive waste water

Solar-driven desalination is an energy-saving and environmentally benign wastewater treatment technology. A method of in situ self-reduction of graphene oxide (rGO) by cheap geopolymer was introduced, and a photo evaporation membrane device (rGOPGC) for treatment of the simulated high salt liquid radioactive waste (HSLRW) was prepared in the present study. Compared with other rGO based photo evaporation membrane materials, geopolymer matrix has the advantages of low cost, reductant free, simple preparation process and mild conditions. After desalination of simulated seawater, the concentrations of Na+, K+, Ca2+ and Mg2+ ions reached the WHO standard, and the removal rates of radioactive I-, Cs+ and Sr2+ in the simulated high salinity wastewater reached 99.62%, 99.71% and 99.99% respectively; The evaporation rate of rGOPGC remained stable at 1.5 kg/m2/h after 16 cycles in high salinity environment. There was no obvious salt accumulation on the upper surface of the device, indicating its high stability. Furthermore, the evaporation performance at high temperature near the nuclear power plant (NPP) waste water was simulated and tested. Under one solar intensity and 35 °C ambient temperature, the evaporation rate of 1.75 kg/m2/h and the evaporation efficiency of 98.51% were achieved. The results indicated that the rGOPGC device is potential in the concentration evaluation of HSLRW.

EVALUATION OF ENGINEERING PROPERTIES OF THERMAL POWER PLANT WASTE FOR SUBGRADE TREATMENT

Soft cohesive soils have low strength, high plasticity, and a large expansion ratio making them unsuitable as a road subgrade. This study aims to evaluate the potential of power plant waste (fly ash) from the Barapukuria Thermal Power Plant, Dinajpur, Bangladesh to improve the characteristics of such soft cohesive soil. X-ray fluorescence test conducted to classify the power plant fly ash and the type was identified as “Class F” according to “American Association of State Highway and Transportation Officials” and "American Society for Testing and Materials". Laboratory tests were conducted on clay soil obtained from Dinajpur region modified by the collected power plant waste. As the Class F fly ash has low cementing property, 3% cement was added with it. Cement mixed soil was modified with 5%, 10%, 15%, and 20% fly ash respectively. Specific Gravity, Atterberg limits, Modified Proctor Compaction, Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) tests were conducted. The study reveals that there is a decrease in specific gravity, dry density, and plasticity index with the addition of power plant waste. On the other hand, there is an increase in optimum moisture content, UCS, and CBR value. UCS and CBR values were found to be improved remarkably. Soaked CBR value of soil is found to be improved from 2.79% to 92.59% when treated with 5% fly ash and 3% cement. The UCS value of this modified soil was 560.36 kPa. The stabilized soil thus obtained meets the requirements for subgrade as specified by the Local Government Engineering Department (LGED)’s design manual (2005), Bangladesh. Since there is a possibility of leaching by dumping a large quantity of fly ash in the pond, the use of fly ash from the power plants to improve soft cohesive soils for road subgrade may be an environment-friendly alternative to its disposal in the ponds.