Plastic pollution is a universal problem, and microbial management of plastic waste represents a promising area of biotechnological research. This study investigated the ability of bacterial strains which were isolated from landfill soil to degrade Low-Density Polyethylene (LDPE). Strains obtained via serial dilution were screened for LDPE degradation on Minimal Essential Medium (MEM) with hexadecane. Nine isolates producing clearance zones on hexadecane-supplemented MEM were further tested for biofilm formation on LDPE sheets. High cell surface hydrophobicity isolates (>10%) were selected for detailed biodegradation studies. The C-8 bacterial isolate showed the highest LDPE weight loss (3.57%) and exhibited maximum laccase (0.0219 U/mL) and lipase activity (19 mm) among all bacterial isolates after 30 days. Weight loss was further validated by FTIR and SEM analysis. FTIR analysis revealed that in comparison to control, changes in peak were observed at 719 cm-1 (C-H bending), 875.67 cm-1 (C-C vibrations), 1307.07 cm-1 (C-O stretching), 1464.21 cm-1 (C-H bending), 2000-1650 cm-1 (C-H bending), 2849.85 cm-1 (C-H stretching) in microbial treated LDPE sheets. The treated LDPE also displayed increase in carbonyl index (upto 2.5 to 3 folds), double bond index (1 to 2-fold) and internal double bond index (2 to 2.5-fold) indicating oxidation and chain scission in the LDPE backbone. SEM analysis showed substantial micrometric surface damage on the LDPE film, with visible cracks and grooves. Using 16S rRNA gene sequencing, the C-8, C-11, C-15 and C-19 isolate were identified as Bacillus paramycoides, Micrococcus luteus, Bacillus siamensis and Lysinibacillus capsica, respectively.

Sustainability is defined as the process of developing and responsibly sustaining a healthy built environment based on resource-efficient and ecological principles. When it comes to sustainability, earthen construction is a good choice because of its minimal carbon impact and lower operating expenses. This study investigates the cost comparison between Alker and a reinforced concrete office with a dimension of 6 x 6 m. Alker is a stabilised form of earthen building. Based on the dry weight of the soil, it contains 10% gypsum, 2% lime, and 20%-22% water. Shredded plastic waste (SPW) was added to Alker to improve its properties with the addition of the environmental effect of plastic waste. The results showed that the office built with reinforced concrete had a total cost of Turkish Lira;119 348.57 (6630), whereas the building built with Alker materials had a total cost of Turkish Lira;103 474.19 (5748). Therefore, offices built with Alker's added SPW are 13% cheaper than offices built with reinforced concrete. Alker modified with shredded plastic waste has been demonstrated to be a sustainable building material with enhanced properties.

Clay soils are known to have a high swelling pressure with an increase in water content. This behavior is considered a serious hazard to structures built upon them. Various mechanical and chemical treatments have historically been used to stabilize the swelling behavior of clay soils. This work investigates the potential use of shredded plastic waste to reduce the swelling pressure and compressibility of clay soils. Two types of highly plastic clay (CH) soils were selected. Three different dimensions of plastic waste pieces were used, namely lengths of 0.5 cm, 1.0 cm, and 1.5 cm, with a width of 1 mm. A blend of plastic-cement waste with a ratio of 1:5 by weight was prepared. Different fractions of the plastic-cement waste blend with a 2 wt.% increment were added to the clay soil, which was then remolded in a consolidometer ring at 95% relative compaction and 3.0% below the optimum. The zero swell test, as per ASTM D4546, was conducted on the remolded soil samples after three curing periods: 1, 2, and 7 days. This method ensures the accurate evaluation of swell potential and stabilization efficiency over time. The experimental results showed that the addition of 6.0-8.0% of the blend significantly reduced the swelling pressure, demonstrating the mixture's effectiveness in soil stabilization. It also reduced the swell potential of the expansive clay soil and had a substantial effect on the reduction in its compressibility, especially with a higher aspect ratio. The compression index decreased, while the maximum past pressure increased with a higher plastic-cement ratio. The 7-day curing time is the optimum time to stabilize expansive clay soils with the plastic-cement waste mixture. This study provides strong evidence that plastic waste can enhance soil mechanical properties, making it a viable geotechnical solution.

Global economic growth leads to massive plastic waste increase, posing severe environmental challenges worldwide. Addressing it demands innovative solutions like repurposing plastics for construction. Extensive engineering and environmental assessments can accelerate their adoption. This study explores the potential incorporation of plastic waste (in flake and pellet forms) into a cement-treated fine-grained soil through a comprehensive geotechnical experimental testing program and Life Cycle Assessment (LCA) study to assess their environmental sustainability. Experimental investigations were conducted on four distinct plastic types, namely polypropylene (PP), high-density polyethylene (HDPE), polylactic acid (PLA), and polyethylene terephthalate (PET), with varying weight percent inclusions of 2 %, 4 %, and 6 %. Results revealed a decreasing trend in maximum dry densities and strength (both unconfined compressive strength (UCS) and split tensile strength (STS)) with increasing plastic content. Sorptivity of soil generally increased with plastic inclusions, yet in the case of PET, for plastic content > 4 %, a notable drop in the rate of increase was observed. California bearing ratio (CBR) test results indicated a reduction in the CBR values by up to 18.33 % for 6 % plastic inclusions. LCA study findings favoured plastic flakes over pellets as a more sustainable material choice, exhibiting a lower environmental impact across all assessed indicators. This research findings offer insights into the potential utilization of plastic waste and promote sustainable geomaterial choices in road pavement construction.

The escalating global crisis of plastic waste necessitates innovative and sustainable approaches to its management. This study explores a novel method; the transformation of discarded plastic materials into high quality 3D printing filaments, offering a promising solution to this pervasive environmental challenge. This review paper delves into the prospects of leveraging plastic waste recycling for the production of 3D printing filaments, thereby advancing the cause of sustainable additive manufacturing. The investigation encompasses a comprehensive examination of the recycling process, encompassing waste collection, sorting, and filament extrusion. The outcomes of this study underscore the substantial potential of recycling plastic waste for 3D printing filaments as a sustainable alternative to conventional manufacturing. This review also delves into the polymer degradation phenomenon, assessment of properties of recycled polymers, and environmental impact assessment, conducting a comparative analysis with traditional filament production methods. This paper advances the application of recycling plastic waste for 3D printing filaments, offering a tangible and immediate response to the global plastic waste crisis.

This research explores, for the first time, the use of plastic waste to enhance the mechanical properties of Tunis soft clay, a soil known for its low stability. Soil samples mixed with 2%, 5%, and 7% plastic waste were subjected to pre-consolidation tests up to 80 kPa, followed by unloading. The results show a significant reduction in consolidation time and void ratio, along with an increase in undrained cohesion. The optimal percentage of 5%, higher than the commonly reported 4%, provides notable improvements for applications in foundations and embankments. This study opens new perspectives for better plastic waste management while offering an innovative solution to geotechnical challenges. However, further studies on implementation techniques, such as deep compaction, are needed to validate its practical application.

Co-liquefaction is an emerging technology aimed at enhancing bio-oil yield and quality, compensating for decrease in feedstock, increasing productivity, and adding revenue to bio-refineries. This study delves into the influence of plastic waste (PW) types during co-liquefaction with cotton gin trash (CGT) on the yield and quality of the produced crude oil. Various plastics, including PLA (polylactic acid), PVA (polyvinyl alcohol), PET (polyethylene terephthalate), LDPE (low-density polyethylene), HDPE (high-density polyethylene), PP (polypropylene), and PS (polystyrene), were investigated in a mixing ratio of 2:1 (CGT/plastic waste) at 320 degrees C and 2 hours in supercritical ethanol (ScEtOH), without catalyst, to produce energy -dense bio-oil under optimised conditions. The study presents the suitability of different types of plastic waste for co-feeding with CGT, along with their synergistic and antagonistic effects on product fraction yield (oil, solid, and gas), and oil energy yield. High bio-oil yields of 54.5 wt%, 53.7 wt%, and 43.1 wt% were achieved during co-liquefaction of CGT with PLA, PET and PVA, respectively. Bio-oil with the highest Higher Heating Values (HHV) was achieved through the coliquefaction of CGT with PVA (30.6 MJ/kg) and PS (31.5 MJ/kg). The solid fractions obtained from co-liquefying CGT with PLA and PVA contained 46.9 wt% and 55.1 wt% carbon, respectively, making them potential sustainable sources for soil amendment. Furthermore, the bio-oils were characterised using gas chromatographymass spectroscopy (GC-MS), two-dimensional nuclear magnetic spectroscopy-heteronuclear single quantum coherence (2D-NMR-HSQC), elemental analysis, fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) to assess their quality and stability. Solid residues were characterised to understand the extent of plastic degradation and their suitable applications. The results indicate that the co-liquefaction of lignocellulosic biomass with plastics represents a viable and promising approach for improving bio-oil quality and extending its shelf life.

Maintaining and enhancing soil stability for electrical pylon installation is very vital to provide an uninterrupted energy supply. Conventionally, the stability of soil is maintained using the chemical stabilization technique, which has its limitations, is not environmentally friendly, may not provide a stable soil condition in the longer term, is and prone to disruption. Therefore, in this work, a more sustainable approach is suggested where a biomediated technique where microbes from biological degradations of vegetables are used to integrate with polyethylene terephthalate (PET) plastic waste as a soil stabilizer. The findings of the triaxial shear test showed that the treated soil enhanced the soil's resistance to shearing forces by 33% due to the bridging effect and soil interlocking. The combination of 20% of fermented vegetables grout liquid and 1% of PET has improved the soil's cohesion significantly. The slope stability test also proved that the PET additions could improve the factor of safety (FOS) up to 81.47% and exceed the minimum requirement of a stable design slope as compared to the untreated slope. The results proved the influence of the bio-mediated technique with different variations of PET addition is an effective method to improve the engineering properties of the slope.

The waste materials such as fly ash, construction demolition waste, and plastic waste are generated in tremendous quantities and are dumped haphazardly thereby causing irreparable damage to the environment. Proper utilization of these wastes particularly in the construction sector will protect the environment from their harmful effects and will prove to be economical through the preservation of precious natural resources. This paper presents an investigation on the utilization of lime, fly ash, and construction demolition waste individually and in combination with each other for the stabilization of poor soil. The utilization of plastic waste along with soil-fly ash-construction demolition waste-lime composite was further investigated. The samples for unconfined compressive strength and split tensile strength were compacted at optimum moisture content to maximum dry density, which was obtained from standard Proctor compaction tests. The samples were tested after 7 days, 28 days, and 56 days of curing periods. The results reveal that the addition of admixtures increases the unconfined compressive strength and split tensile strength, and the optimum mixes were selected based on 7 days of unconfined compressive strength. The increase in strength with the addition of admixtures depends on the type of admixture used and the formation of new minerals, which can be observed from XRD graphs. The soaked California bearing ratio tests were conducted on the optimum mixes and soil-fly ash-C&D waste-lime mix was selected as the best sub-grade material compared to other material combinations based upon economic and environmental considerations.