Constructed wetlands (CWs) have emerged as effective nature-based solutions (NbS) for the treatment of industrial dairy wastewater (DWW), which is characterized by high organic loads, elevated nutrient concentrations, and pronounced operational variability. Despite increasing implementation, quantitative engineering evidence supporting design optimization and scalability remains fragmented. Herein, we present a semi-quantitative synthesis of CW performance for DWW treatment, explicitly linking hydraulic and operational parameters with pollutant removal efficiencies. A systematic review of 38 peer-reviewed studies published between 1995 and 2025 was conducted in accordance with PRISMA 2020 guidelines. Treatment performance was normalized and evaluated as a function of hydraulic retention time (HRT), organic loading rate (OLR), system configuration, and climatic context. The results demonstrate that hybrid CWs combining vertical and horizontal subsurface flow most frequently achieved COD and BOD₅ removal efficiencies exceeding 90% when operated within an observed operating envelope, typically including HRT ranges of 4–8 h (VSSF; n = 4) and 3–7 days (HSSF; n = 14), and OLR values below 30 g COD m⁻² d⁻¹ (n = 7, among studies reporting OLR). Operation outside this operating envelope was generally associated with reduced treatment stability and an increased likelihood of operational constraints (e.g., clogging). Substrate porosity, vegetation diversity, and climate further modulated long-term performance and system resilience. Based on the consolidated evidence, this review suggests transferable operational design envelopes and configuration-specific implementation pathways that translate empirical findings into practical engineering guidance, supporting the scalable adoption of CWs as low-energy NbS for decentralized and sustainable DWW management.

The rapid growth of urban areas has increased the need for more efficient methods of pavement inspection and maintenance. However, conventional techniques remain slow, labor-intensive, and limited in spatial coverage, and their performance is strongly affected by traffic, weather conditions, and operational constraints. In response to these challenges, it is essential to synthesize the technological advances that improve inspection efficiency, coverage, and data quality compared to traditional approaches. Herein, we present a systematic review of the state of the art on the use of unmanned aerial vehicles (UAVs) for monitoring and assessing pavement deterioration, highlighting as a key contribution the comparative integration of sensors (photogrammetry, LiDAR, and thermography) with recent automatic damage-detection algorithms. A structured review methodology was applied, including the search, selection, and critical analysis of specialized studies on UAV-based pavement evaluation. The results indicate that UAV photogrammetry can achieve sub-centimeter accuracy (<1 cm) in 3D reconstructions, LiDAR systems can improve deformation detection by up to 35%, and AI-based algorithms can increase crack-identification accuracy by 10% to 25% compared with manual methods. Finally, the synthesis shows that multi-sensor integration and digital twins offer strong potential to enhance predictive maintenance and support the transition towards smarter and more sustainable urban infrastructure management strategies.

Constructed wetlands (CWs), increasingly adopted as nature-based solutions (NBS) for wastewater treatment, require a rigorous assessment of the durability and structural performance of the materials used in their supporting systems. In contrast to the extensive literature addressing hydraulic efficiency and contaminant removal, the structural behavior of CWs has been scarcely examined, with existing studies offering only general references to reinforced concrete and masonry and lacking explicit design criteria or deterioration analyses. This study integrates evidence from real-world CW installations with a systematic review of 31 studies on the degradation of cementitious materials in analogous environmental conditions, following PRISMA 2020 guidelines, with inclusion criteria based on quantified wastewater-related exposure conditions (e.g., chemical aggressiveness, persistent saturation, and biogenic activity). Results indicate that reinforced concrete, despite its structural capacity, is susceptible to biogenic corrosion, accelerated carbonation, and sulfate–chloride attack under conditions of persistent moisture, with reported degradation rates in analogous wastewater infrastructures on the order of millimeters per year for concrete loss and tens of micrometers per year for reinforcement corrosion. Masonry structures, similarly, exhibit performance constraints when exposed to mechanical overloads and repeated wetting–drying cycles. In contrast, emerging alternatives—such as nanomodified matrices and concretes incorporating supplementary cementitious additives—demonstrate potential to enhance durability while contributing to a reduced carbon footprint, without compromising mechanical strength. These findings reinforce the need for explicit structural design criteria tailored to CW applications to improve sustainability, durability, and long-term performance.

Portland cement production is a major source of global CO₂ emissions due to its high energy consumption and calcination processes. This study proposes a sustainable alternative through the partial replacement of cement with alkali-activated pumice, a naturally occurring aluminosilicate material with high regional availability. Mixes with 0%, 10%, 20%, and 30% cement replacement were designed for pedestrian slabs exposed to humid tropical conditions. Compressive strength was evaluated using non-destructive testing over a period of 364 days, and carbonation was analyzed at different ages. The results show that mixes with up to 30% pumice maintain adequate strength levels for light-duty applications, although with a more gradual strength development. A significant reduction in carbonation depth was also observed, especially in the mix with the highest replacement level, suggesting greater durability in aggressive environments. These findings support the use of pumice as a viable and sustainable supplementary cementitious material in tropical regions, promoting low-impact construction practices.

Constructed wetlands (CWs) are widely used as nature-based solutions for domestic wastewater treatment; however, long-term exposure of concrete infrastructure to saturated and chemically active environments may compromise its durability. This study evaluates the mechanical performance and carbonation progression of concrete specimens exposed for one year in a full-scale CW system. Cylindrical specimens (10 × 20 cm) with design compressive strengths of 150, 200, and 250 kg/cm² were placed in three hydraulic zones (inlet, middle, and outlet). A full factorial design (3³) was implemented to assess the effects of exposure zone, concrete strength, and immersion time on compressive strength and carbonation depth. Compressive strength exhibited moderate reductions (8–15%) and remained primarily governed by the initial design strength, with significant main effects and non-significant interaction effects (p > 0.05). In contrast, carbonation depth increased progressively over time and showed clear spatial variability, reaching approximately 8–12 mm under lower exposure conditions and up to ~15 mm in outlet-zone specimens after one year, with a significant interaction between exposure zone and concrete strength (p < 0.001). These findings indicate that chemical degradation processes may advance even when mechanical performance remains relatively stable, highlighting the importance of incorporating durability considerations and spatial exposure conditions into the design and monitoring of concrete infrastructure in CW systems.

Soil stabilization is widely applied in transportation engineering to enhance the mechanical performance and serviceability of road subgrades, particularly in fine-grained soils susceptible to moisture-induced deterioration. Although Portland cement provides rapid strength development and high load-bearing capacity, its high energy consumption and associated CO₂ emissions have encouraged the exploration of lower-impact stabilization alternatives. This study presents a performance-based comparative evaluation of fine-grained soils stabilized with Portland cement and kaolin at dosages of 3%, 5%, and 7% by dry soil mass. The experimental program included soil characterization, Standard Proctor compaction testing, and unconfined compressive strength (UCS) testing conducted at curing ages of 0, 7, 14, 28, 90, and 180 days. Cement-treated soils exhibited faster early-age strength development and higher long-term UCS values, supporting applications requiring early load-bearing capacity. In contrast, kaolin-treated soils showed gradual and stable strength gains primarily associated with densification and particle rearrangement mechanisms. Overall, the results demonstrate that kaolin can serve as a viable low-impact stabilizer for low-volume and secondary road infrastructure. The findings support performance-based and sustainability-oriented material selection strategies for context-sensitive road subgrade design.