Highly Stretchable, Biodegradable, and Recyclable Green Electronic Substrates.

As a steady stream of electronic devices being discarded, a vast amount of electronic substrate waste of petroleum-based nondegradable polymers is generated, raising endless concerns about resource depletion and environmental pollution. With coupled reagent (CR)-grafted artificial marble waste (AMW@CR) as functional fillers, polylactic acid (PLA)-based highly stretchable biodegradable green composite (AMW@CR-SBGC) is prepared, with elongation at break up to more than 250%. The degradation mechanism of AMW@CR-SBGC is deeply revealed. AMW@CR not only contributed to the photodegradation of AMW@CR-SBGC but also significantly promoted the water degradation of AMW@CR-SBGC. More importantly, AMW@CR-SBGC showed great potential as sustainable green electronic substrates and AMW@CR-SBGC-based electronic skin can simulate the perception of human skin to strain signals. The outstanding programmable degradability, recyclability, and reusability of AMW@CR-SBGC enabled its application in transient electronics. As the first demonstration of artificial marble waste in electronic substrates, AMW@CR-SBGC killed three birds with one stone in terms of waste resourcing, e-waste reduction, and saving nonrenewable petroleum resources, opening up vast new opportunities for green electronics applications in areas such as health monitoring, artificial intelligence, and security.

Third generation biobutanol production by Clostridium beijerinckii in a medium containing mixotrophically cultivated Dunaliella salina biomass.

This study aims the third generation biobutanol production in P2 medium supplemented D. salina biomass mixotrophically cultivated with marble waste (MW). The wastes derived from the marble industry contain approximately 90% of carbon-rich compounds. Microalgal growth in mixotrophic conditions was optimized in the 0.4-2 g/L of MW concentration range. The highest microalgal concentration was obtained as 0.481 g/L in the presence of 1 g/L MW. Furthermore, some important parameters for the production of biobutanol, such as microalgal cultivation conditions, initial mixotrophic microalgal biomass loading (50-300 g/L), and fermentation time (24-96 h) were optimized. The highest biobutanol, total ABE, biobutanol yield and productivity were determined as 11.88 g/L, 13.89 g/L, 0.331 g/g and 0.165 g/L/h at the end of 72 h in P2 medium including 60 g/L glucose and 200 g/L microalgal biomass cultivated in 1 g/L MW, respectively. The results show that D. salina is a suitable raw material for supporting Clostridium beijerinckii DSMZ 6422 cells on biobutanol production. To the best of our knowledge, this is the first study on the use of MW which is a promising feedstock on the mixotrophic cultivation of D. salina for biobutanol production.

The preparation of paddy soil amendment using granite and marble waste: Performance and mechanisms.

The wastes generated from the mining and processing of granite and marble stone are generally regarded as useless. However, these waste materials were used as the soil amendments for the first time. The functional groups, crystalline structure and micro-morphology of granite and marble wastes amendments (GMWA) were different from the original wastes demonstrated by X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR) and Scanning electron microscope-energy dispersive spectrometer (SEM-EDS) analyses. With the addition of the amendments, the cation exchange capacity, electrical conductivity and nutrient availability of the soil increased, and the extractable heavy metals of the soil reduced significantly. Under the condition of the addition of 3% amendments, 7.0%, 99.9%, 99.7% and 70.5% of Cu, Pb, Zn and Cd in exchangeable fractions in soil were transformed to the more stable Fe-Mn oxides- or carbonates-bounded fractions. Tessier method and correlation analysis showed that the reduction of extractable metals in the acidic paddy soil can be attributed to the adsorption of available SiO2, the co-precipitation induced by the elevated pH value, the complexation induced by Fe-Mn oxides and the cation exchange induced by mineral nutrients. This study provides a new strategy for resource recovery of waste stones and remediation of heavy metal-contaminated soil.

A multifunctional plant for a sustainable reuse of marble waste toward circular economy.

The marble processing cycle involves the production of large quantities of wastes whose disposal represents an economic and environmental concern for marble companies due to the difficulty of identifying suitable landfills and the high transfer costs. In this context, the design of a sustainable industrial plant that allows the reuse of the calcium carbonate (CaCO3) contained in the marble waste is extremely challenging. With this recognition, the main industrial applications of CaCO3 are firstly analyzed in the present work to identify the physical-chemical properties required to CaCO3 in these contexts. Later, different plant solutions are suggested to recover CaCO3 from marble sludge in order to allow its use in industrial applications. The designed industrial plant includes an energy efficient drying phase, which exploits the thermal waste of the exhaust gases produced in a cogeneration section, and a subsequent milling phase. Since marble wastes currently constitute an economic burden for companies and an environmental emergency for the Public Administration, the performed technical-economic analysis shows that its recovery may represent an opportunity of sustainable development for the marble sector.

Effects of Maleic Anhydride-Grafted Polyethylene on the Properties of Artificial Marble Waste Powder/Linear Low-Density Polyethylene Composites with Ultra-High Filling Content.

The need to reach carbon neutrality as soon as possible has made the use of recycled materials widespread. However, the treatment of artificial marble waste powder (AMWP) containing unsaturated polyester is a very challenging task. This task can be accomplished by converting AMWP into new plastic composites. Such conversion is a cost-effective and eco-friendly way to recycle industrial waste. However, the lack of mechanical strength in composites and the low filling content of AMWP have been major obstacles to its practical application in structural and technical buildings. In this study, a composite of AMWP/linear low-density polyethylene (LLDPE) filled with a 70 wt% AMWP content was fabricated using maleic anhydride-grafted polyethylene as a compatibilizer (MAPE). The mechanical strength of the prepared composites is excellent (tensile strength ~18.45 MPa, impact strength ~51.6 kJ/m2), making them appropriate as useful building materials. Additionally, laser particle size analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and thermogravimetric analysis were used to examine the effects of maleic anhydride-grafted polyethylene on the mechanical properties of AMWP/LLDPE composites and its mechanism of action. Overall, this study offers a practical method for the low-cost recycling of industrial waste into high-performance composites.

Combined application of marble waste and beneficial microorganisms: toward a cost-effective approach for restoration of heavy metals contaminated sites.

Heavy metal (HM) pollution and the need to preserve the environment have gathered increasing scientific attention. The immobilization of HMs into less-soluble, less mobile, and less toxic forms in addition to the improvement of Medicago sativa L. growth and HMs accumulation were evaluated after the application of marble waste (MW) and/or beneficial PGP rhizobacteria and mycorrhizae to the mining soil compost. A greenhouse assay was conducted to elucidate the influence of both amendment and beneficial microorganisms. The application of marble waste to the soil-compost resulted in decreasing the bioavailability of metals (Cu, Zn, Pb, and Cd), thus ameliorating the installation of the vegetal cover for 6 months of culture. Cultivation of M. sativa under 5% MW-amended soil for 6 months increased the shoot dry weight by almost twofold, while the inoculation with rhizobacteria-mycorrhizae combined with the application of 15% MW resulted in an improvement of 3.5-fold in case of shoot dry weight. In addition, the application of marble waste amendment or their combination with metallo-resistant bacteria resulted in decreasing HM accumulation leading to HM content below the threshold recommended for animal grazing. Thus, the application of amendments and beneficial microorganisms appeared to guarantee the safe cultivation of alfalfa for 6 months of culture. The dual combination amendments and beneficial microorganisms showed the good potential to restore HM polluted soils and could stand as a novel approach for restoration of HM-contaminated soils.

An integrated approach towards marble waste management: GIS, SFA, and recycling options.

Marble units generate an enormous amount of non-biodegradable waste during the processing operations and are considered one of the environmentally unfriendly industrial sectors. This sector has become a global nuisance due to its multi-dimensional damaging nature. Therefore, a multidimensional approach is needed to geographically describe the pollution sources, their waste load, collection mechanism, and their proper disposal or reuse. This article highlights an integrated approach to sorting out the multidimensional issues associated with the marble sector. More than 150 marble processing units (MPUs) are scattered in the study area pouring waste into the environment in the form of slurry. The produced waste roots environmental issues both for fauna and flora of the terrestrial and aquatic segments of the environment. A geospatial-based attempt has been made through geographic information system (GIS) for the identification and description of the pollution sources, MPUs, in the study area. The quantitative assessment has been made through substance flow analysis (SFA) by taking raw marble as the input source and marble product as output. Furthermore, material characterization has been carried out to confirm the chemical composition of the slurry waste for its potential use. Results confirmed that a major part (> 90%) of marble powder is calcium carbonate (CaCO3) which has so many potential uses as raw material. The integrated approach of GIS, SFA, and chemical characterization set forth a model that satisfies multi-dimensional queries regarding pollution sources, pollution load, and sustainable solutions to the problem. The output integrated model provides a digital environmental baseline for the monitoring of MPUs, the amount of waste generated by these MPUs, and its potential reuse options. The proposed model can be utilized worldwide as a decision support tool due to its optimum results.

A study on the applicability of scoria gravel an alternative base course material through blending with marble waste aggregate.

This study aims to evaluate the applicability of Scoria gravel as an alternative base course material in flexible pavements through blending with marble waste aggregate (MWA) by modifying the physical and mechanical engineering properties of scoria. Non-Probabilistic sampling techniques and experimental methods were used. To achieve the objectives of the study, the laboratory tests were passed in three steps. First, the Engineering properties of materials were independently tested; the result proves the marginality of scoria gravel. Second, scoria gravel was mechanically stabilized by 20% percentages by weight increments of MWA. The obtained engineering properties test results at 20:80 Scoria to MWA mix ratios are 2.56%, 21.38%, 18.59%, 19.27%, 17.45%, 13.77%, Non-Plastic, 1.21%, and 73.4%, for Specific Gravity, Aggregate Crushing Value, Aggregate Impact Value, Loss Angeles Abrasion, Flakiness Index, Elongation Index, Atterberg's limit, Water Absorption, and California Bearing Ratio (CBR) respectively. These test results fulfilled the ERA standard specification for GB2 and GB3 base course materials. However, the CBR test results showed a failure to meet the standard spécification. Thus, 20:80 Scoria to MWA percentage by weight ratio was selected as a control mixture. So, Crushed Stone Aggregate was added at 5% percentage by weight to improve the CBR of scoria gravel. Therefore, the CBR value of 82.13% attained the ERA standard Specification limit for base course materials at 15:60:25 percentages by weight ratio of scoria gravel, MWA, and CSA respectively. Finally, Based on this study it was recommended to use scoria gravel as an alternative base course construction material, when it was found abundantly near construction vicinity.

Marble waste site suitability assessment using the GIS-based AHP model.

Site suitability with regards to environmental protection, public concerns, and the legitimate prerequisite is a basic issue that has been tended to in this study. By and large, marble waste is being unloaded on accessible open spaces or released in water to the close by waterways in the territory, Mohmand marble zone (Shabqadar), Khyber Pakhtunkhwa, Pakistan. Suitability assessment for marble waste collection and disposal was carried out through the integrated approach of analytical hierarchy process (AHP) and geographic information system (GIS) to limit the ecological dangers, public, and government concerns related to marble waste. The available land use was ordered into three main land use classes followed by six sub-classes including water bodies and agriculture (environmental), settlement and social site (social), and marble units and roads (economic). These sub-classes in the investigation region were organized through pairwise correlation and weighted sum analysis, AHP procedure. The AHP results were interpreted through GIS tools of digitization, buffering, and overlay in ArcMap, ArcGIS. The integrated AHP and GIS outcomes were consolidated to get the optimum results of the study, marble waste collection, and disposal options. It was concluded that priority should be given to water bodies followed by agricultural land while protecting the available land use classes from marble waste hazards. The percent priority values calculated are 32.33%, 30.50%, 12.16%, 10.66%, 8.50%, and 6% for water bodies, agricultural land, settlements, marble processing units, roads, and cultural sites respectively. The sequence of priority of the land use values are waterbodies > agriculture > settlement > marble industries > road > cultural site. The proposed integrated model is helpful in site suitability for waste management by the authorities and decision-makers associated with waste management.

Prediction of Strength Properties of Concrete Containing Waste Marble Aggregate and Stone Dust-Modeling and Optimization Using RSM.

Carbon footprint reduction, recompense depletion of natural resources, as well as waste recycling are nowadays focused research directions to achieve sustainability without compromising the concrete strength parameters. Therefore, the purpose of the present study is to utilize different dosages of marble waste aggregates (MWA) and stone dust (SD) as a replacement for coarse and fine aggregate, respectively. The MWA with 10 to 30% coarse aggregate replacement and SD with 40 to 50% fine aggregate replacement were used to evaluate the physical properties (workability and absorption), durability (acid attack resistance), and strength properties (compressive, flexural, and tensile strength) of concrete. Moreover, statistical modeling was also performed using response surface methodology (RSM) to design the experiment, optimize the MWA and SD dosages, and finally validate the experimental results. Increasing MWA substitutions resulted in higher workability, lower absorption, and lower resistance to acid attack as compared with controlled concrete. However, reduced compressive strength, flexural strength, and tensile strength at 7-day and 28-day cured specimens were observed as compared to the controlled specimen. On the other hand, increasing SD content causes a reduction in workability, higher absorption, and lower resistance to acid attack compared with controlled concrete. Similarly, 7-day and 28-day compressive strength, flexural strength, and tensile strength of SD-substituted concrete showed improvement up to 50% replacement and a slight reduction at 60% replacement. However, the strength of SD substituted concrete is higher than controlled concrete. Quadratic models were suggested based on a higher coefficient of determination (R2) for all responses. Quadratic RSM models yielded R2 equaling 0.90 and 0.94 for compressive strength at 7 days and 28 days, respectively. Similarly, 0.94 and 0.96 for 7-day and 28-day flexural strength and 0.89 for tensile strength. The optimization performed through RSM indicates that 15% MWA and 50% SD yielded higher strength compared to all other mixtures. The predicted optimized data was validated experimentally with an error of less than 5%.

Recycling of ceramic tiles waste and marble waste in sustainable production of concrete: a review.

Currently, recycling of waste materials in construction is being considered very important because waste generation is posing serious threats to our living environment. Hence, to induce sustainability in the ongoing urban development, researchers around the globe are using numerous wastes in concrete as partial substitutes of binders (cement, lime, etc.) and fillers (fine and coarse aggregates) with the aim of reducing the depletion of natural resources and cutting the carbon dioxide emissions emerging from increased demand and production of cement. This review paper has summarized the findings of literature relating to recycling of marble wastes and ceramic tiles wastes in production of concrete. The physical, fresh-state, and strength properties of concrete were reviewed from available extensive literature, and it was found that the concrete prepared from marble waste and ceramic waste as partial substitution of cement and aggregates is expected to perform at least comparable to conventional cement concrete and better if applicable. Both marble wastes and ceramic tiles wastes can be incorporated and recycled in concrete as cementitious materials and aggregate replacing materials. With such approach, the concrete can be made strong and durable, and the issues relating to depletion of natural resources and environmental degradation can also be solved without compromising sustainability in infrastructure development.

An Experimental and Empirical Study on the Use of Waste Marble Powder in Construction Material.

Marble is currently a commonly used material in the building industry, and environmental degradation is an inevitable consequence of its use. Marble waste occurs during the exploitation of deposits using shooting technologies. The obtained elements most mainly often have an irregular geometry and small dimensions, which excludes their use in the stone industry. There is no systematic way of disposing of these massive mounds of waste, which results in the occurrence of landfills and environmental pollution. To mitigate this problem, an effort was made to incorporate waste marble powder into clay bricks. Different percentage proportions of marble powder were considered as a partial substitute for clay, i.e., 5-30%. A total of 105 samples were prepared in order to assess the performance of the prepared marble clay bricks, i.e., their water absorption, bulk density, apparent porosity, salt resistance, and compressive strength. The obtained bricks were 1.3-19.9% lighter than conventional bricks. The bricks with the addition of 5-20% of marble powder had an adequate compressive strength with regards to the values required by international standards. Their compressive strength and bulk density decreased, while their water absorption capacity and porosity improved with an increased content of marble powder. The obtained empirical equations showed good agreement with the experimental results. The use of waste marble powder in the construction industry not only lowers project costs, but also reduces the likelihood of soil erosion and water contamination. This can be seen to be a crucial factor for economic growth in agricultural production.

Marble Waste Sludges as Effective Nanomaterials for Cu (II) Adsorption in Aqueous Media.

This study evaluated the waste generated by a Spanish marble-producing company as adsorbent for the removal of copper (Cu [II]) from aqueous media. Six marble waste sludge samples were studied, and the following operational parameters were analyzed in discontinuous regime, including pollutant concentration, pH, temperature, nature of aqueous medium, and ionic strength. The applicability of the adsorbent material was assessed with experiments in both continuous and discontinuous regimes under close-to-real-life conditions. A pseudo-second order model yielded a better fit to the kinetic data. Application of the intraparticle diffusion model revealed two well-differentiated adsorption stages, in which the external material transfer is negligible and intraparticle diffusion is the controlling stage. The equilibrium study was better fitted to a Freundlich-type isotherm, predicting elevated maximum adsorption values (22.7 mg g-1) at a relatively low initial Cu (II) concentration (25 ppm), yielding a highly favorable chemisorption process (n >> 1). X-ray fluorescence study identified calcite (CaCO3) as the main component of marble waste sludges. According to X-ray diffraction analysis, Cu (II) ion adsorption occurred by intercalation of the metallic cation between CaCO3 layers and by the formation of surface complexes such as CaCO3 and Cu2(CO3)(OH)2. Cu (II) was more effectively removed at medium pH, lower temperature, and lower ionic strength of the aqueous medium. The salinity and dissolved organic matter in surface, ground-, and waste-waters negatively affected the Cu (II) removal process in both continuous and discontinuous regimes by competing for active adsorption sites. These findings demonstrate the applicability and effectiveness of marble-derived waste sludges as low-cost and readily available adsorbents for the treatment of waters polluted by Cu (II) under close-to-real-life conditions.

Life Cycle Assessment of Cement Production with Marble Waste Sludges.

The construction industry has a considerable environmental impact in societies, which must be controlled to achieve adequate sustainability levels. In particular, cement production contributes 5-8% of CO2 emissions worldwide, mainly from the utilization of clinker. This study applied Life Cycle Assessment (LCA) methodology to investigate the environmental impact of cement production and explore environmental improvements obtained by adding marble waste sludges in the manufacture of Portland cement. It was considered that 6-35% of the limestone required for its production could be supplied by marble waste sludge (mainly calcite), meeting the EN 197-1:2011 norm. Energy consumption and greenhouse gas (GHG) emission data were obtained from the Ecovent database using commercial LCA software. All life cycle impact assessment indicators were lower for the proposed "eco-cement" than for conventional cement, attributable to changes in the utilization of limestone and clinker. The most favorable results were achieved when marble waste sludge completely replaced limestone and was added to clinker at 35%. In comparison to conventional Portland cement production, this process reduced GHG emissions by 34%, the use of turbine waters by 60%, and the emission of particles into the atmosphere by 50%. Application of LCA methodology allowed evaluation of the environmental impact and improvements obtained with the production of a type of functional eco-cement. This approach is indispensable for evaluating the environmental benefits of using marble waste sludges in the production of cement.

Transforming Marble Waste into High-Performance, Water-Resistant, and Thermally Insulative Hybrid Polymer Composites for Environmental Sustainability.

Marble waste is generated by marble processing units in large quantities and dumped onto open land areas. This creates environmental problems by contaminating soil, water, and air with adverse health effects on all the living organisms. In this work, we report on understanding the use of calcium-rich marble waste particulates (MPs) as economic reinforcement in recyclable polypropylene (PP) to prepare sustainable composites via the injection molding method. The process was optimized to make lightweight and high-strength thermally insulated sustainable composites. Physicochemical, mineralogical, and microscopic characterization of the processed marble waste particulates were carried out in detail. Composite samples were subsequently prepared via the injection molding technique with different filler concentrations (0%, 20%, 40%, 60%, and 80%) on weight fraction at temperatures of 160, 180, and 200 °C. Detailed analysis of the mechanical and thermal properties of the fabricated composites was carried out. The composites showed a density varying from 0.96 to 1.27 g/cm3, while the water absorption capacity was very low at 0.006%-0.034%. Marble waste particulates were found to considerably increase the tensile, as well as flexural, strength of the sustainable composites, which varied from 22.06 to 30.65 MPa and 43.27 to 58.11MPa, respectively, for the molding temperature of 160 °C. The impact strength of the sustainable composites was found to surge with the increment in filler concentration, and the maximum impact strength was recorded as 1.66 kJ/m2with 20% particulates reinforcement at a molding temperature of 200 °C. The thermal conductivity of the particulates-reinforced sustainable composites was as low as 0.23 Wm-1K-1 at a 200 °C molding temperature with 20% and 40% filler concentrations, and the maximum thermal conductivity was 0.48 Wm-1K-1 at a 160 °C molding temperature with 80% filler concentration. Our findings have shown a technically feasible option for manufacturing a lightweight composite with better mechanical and thermal properties using marble waste particulates as a potential civil infrastructural material.

In-vitro synthesis of marble apatite as a novel adsorbent for removal of fluoride ions from ground water: An ultrasonic approach.

Marble waste powder consisting of calcium and magnesium compounds was used to synthesize a novel biocompatible product, marble apatite (MA) primarily hydroxyapatite (Hap) for applications in defluoridation of drinking water. Synthesis of marble apatite was carried out by using calcium compounds (mixture of hydroxide and nitrate) extracted from marble waste powder which was treated with potassium dihydrogen phosphate at 80°C under alkaline conditions using conventional precipitation method (CM) and ultrasonication method (USM). Qualitative analysis of synthesized marble apatite from both the methods was carried out using FTIR, phase analysis by XRD and microstructure analysis by SEM and TEM. When ultrasonication (USM) method was used, the yield of marble apatite was improved from 67.5% to 78.4%, with reduction in crystallite size (58.46nm), lesser agglomeration and comparatively well-defined spherical morphology compared to the CM method. Studies also include estimation of the defluoridation capacity of MA as an adsorbent for drinking water treatment and effects of process parameters such as pH, contact time, initial fluoride concentration, dosage and presence of other co-ions on fluoride removal capacity. The results showed that the experimental adsorption capacity of the marble apatite synthesized using USM method was significantly higher (1.826mg/g) than marble apatite synthesized using conventional method (0.96mg/g) at pH 7 with a contact time of 90min. The mechanism of adsorption was studied, and it was observed that Langmuir isotherm model fitted best to the experimental data, while the kinetic studies revealed that the process followed pseudo-second order model. This novel compound, marble apatite synthesized from marble waste powder is found to be promising for defluoridation of drinking water and will help in alleviating the problems of fluorosis as well as reduce the problems of disposal of marble waste.

Bioaugmentaton in Technosols created in abandoned pyritic tailings can contribute to enhance soil C sequestration and plant colonization.

Creation of Technosols in combination with phytostabilization may be a sustainable strategy to minimize the environmental and human health hazards derived from mine tailings. Bioaugmentation can facilitate plant establishment and growth for efficient phytostabilization. In order to assess if bioaugmentation can increase soil quality and fertility, decrease metal(loid) mobility and accelerate plant colonization, a one-year field experiment was designed with creation of Technosols in two tailings ponds with different pH (acidic (AT) and neutral (NT)), with addition of marble waste (MaW) and two organic materials (pig manure (PM) and sewage sludge (SS), without or with inoculation of effective microorganisms (EM) at three rates. Results showed that MaW was the main factor responsible for maintaining pH ~7 in AT and ~8 in NT, decreasing salinity, and decreasing the soluble fraction of metals (70-99%). The soluble fraction of As decreased ~45% in AT, related to increases in pH up to neutrality, while increased ~90% in NT with PM due to pH>8 and higher content of organic compounds. The addition of PM and SS significantly increased soil organic C (SOC), nutrient contents and microbial biomass and activity in both tailings, being PM more effective. However, a positive priming effect was observed in NT with SS addition likely due to higher C/N ratio and lack of nutrients. There was a significant effect of EM rate on inorganic C, SOC, N, K and microbial biomass and activity, with higher values as rate increased. Vegetation richness and density directly increased with increasing EM rate. Multivariate analyses showed that the most important properties contributing to increase richness and plant density were microbial biomass and N. Thus, bioaugmentation contributed to soil C sequestration (as organic and inorganic C) and soil fertility, related to high soil microbial biomass and activity, which facilitated an effective colonization of vegetation.

Suitability assessment of grey water quality treated with an upflow-downflow siliceous sand/marble waste filtration system for agricultural and industrial purposes.

The present study examines the suitability assessment of an upflow-downflow siliceous sand/marble waste filtration system for treatment and reuse of grey water collected from bathrooms of the student residential complex at the Higher Institute of Engineering Medjez El Bab (Tunisia). Once the optimization of grey water pre-treatment system has been determined, the filtration system was operated at different hydraulic loading rate and media filter proportions in order to assess the suitability of treated grey water for irrigational purpose according to salinity hazard, sodium hazard, magnesium hazard, permeability index, water infiltration rate, and widely used graphical methods. Suitability of the treated grey water for industrial purpose was evaluated in terms of foaming, corrosion, and scaling. Under optimal operational conditions, results reveals that treated grey water samples with an upflow-downflow siliceous sand/marble waste filtration system may be considered as a good and an excellent water quality suitable for irrigation purpose. However, treated grey water was found not appropriate for industrial purpose due to high concentrations of calcium and sodium that can generate foaming and scaling harm to boilers. These results suggest that treated grey water with an upflow-downflow siliceous sand/marble waste filtration system would support production when used as irrigation water.

Hybrid composites prepared from Industrial waste: Mechanical and swelling behavior.

In this assessment, hybrid composites were prepared from the combination of industrial waste, as marble waste powder (MWP) with conventional fillers, carbon black (CB) as well as silica as reinforcing material, incorporated with natural rubber (NR). The properties studied were curing, mechanical and swelling behavior. Assimilation of CB as well as silica into MWP containing NR compound responded in decreasing the scorch time and cure time besides increasing in the torque. Additionally, increasing the CB and silica in their respective NR hybrid composite increases the tensile, tear, modulus, hardness, and cross-link density, but decreases the elongation and swelling coefficient. The degradation property e.g., thermal aging of the hybrid composite was also estimated. The overall behavior at 70 °C aging temperature signified that the replacement of MS by CB and silica improved the aging performance.