As waste production increases and resources become limited, sewage sludge presents a valuable resource with potential beyond traditional land use and incineration. This review emphasizes exploring innovative non-fertilizer applications of sewage sludges and advocates for viewing wastewater treatment plants as sources of valuable feedstock and carbon sequestration. Innovative uses include integrating sewage sludge into construction materials such as asphalt pavements, geopolymer, cementitious composites, and masonry blocks. These methods not only immobilize heavy metals and mitigate environmental hazards but also support carbon sequestration, contrasting with incineration and land application methods that release carbon into the atmosphere. The review also addresses emerging technologies like bio-adhesives, bio-binders for asphalt, hydrogels, bioplastics, and corrosion inhibitors. It highlights the recovery of valuable materials from sewage sludge, including phosphorus, oils, metals, cellulose, and polyhydroxyalkanoates as well as enzyme production. By focusing on these non-fertilizer applications, this review presents a compelling case for re-envisioning wastewater treatment plants as sources of valuable feedstock and carbon sequestration, supporting global efforts to manage waste effectively and enhance sustainability.

This perspective explores the use of biochar, a carbon-rich material derived from biomass, as a sustainable solution for mitigating volatile organic compounds (VOCs) emitted during asphalt production and use. VOCs from asphalt contribute to ozone formation and harmful secondary organic aerosols (SOAs), which negatively impact air quality and public health. Biochar, with its high surface area and capacity to adsorb VOCs, provides an effective means of addressing these challenges. By tailoring biochar’s surface chemistry, it can efficiently capture VOCs, while also offering long-term carbon sequestration benefits. Additionally, biochar enhances the durability of asphalt, extending road lifespan and reducing maintenance needs, making it a promising material for sustainable infrastructure. Despite these promising benefits, several challenges remain. Variations in biochar properties, driven by differences in feedstock and production methods, can affect its performance in asphalt. Moreover, the integration of biochar into existing plant operations requires the further development of methods to streamline the process and ensure consistency in biochar’s quality and cost-effectiveness. Standardizing production methods and addressing logistical hurdles will be crucial for biochar’s widespread adoption. Research into improving its long-term stability in asphalt is also needed to ensure sustained efficacy over time. Overcoming these challenges will be essential for fully realizing biochar’s potential in sustainable infrastructure development

Bio‐based materials that valorize waste streams while enabling resource conservation are central to advancing circular and sustainable environmental solutions. This study reports the development of ionically crosslinked biochar‐encapsulated hydrogels (Bio‐H) as sustainable adsorbents for the removal of heavy metals from contaminated water systems. Cyanidioschyzon merolae ‐derived biochar, produced by hydrothermal liquefaction of biomass was incorporated into calcium‐crosslinked sodium alginate using a two‐step gelation process, creating a multifunctional, biodegradable composite. Swelling behavior demonstrated that biochar incorporation significantly reduced the initial contraction observed in pristine alginate hydrogels and enabled continuous, monotonic swelling, achieving equilibrium swelling ratios of 1.16 within 7 h, substantially faster than pristine systems. The mechanical integrity of the Bio‐H was assessed by dynamic mechanical analysis (DMA). The storage modulus (G′) exceeded the loss modulus (G″) across the entire 0.1–100 Hz range with no crossover, reaching a plateau of about 372 kPa, confirming a stable, elastically dominant crosslinked network. Scanning electron microscopy revealed an open macroporous network that became textured with particulate deposits after adsorption, with EDS confirming Cu and Fe uptake. Batch adsorption experiments showed that maximum adsorption capacities were achieved at pH 4 and 298 K. The maximum equilibrium adsorption capacity for Cu ²⁺ was 136 mg/g, whereas for Fe ³⁺ , the adsorption capacity was observed to be 1.25 mg/g. The M ₅ model suggests that the adsorption of both metals proceeds through a physical multilayer mechanism, which involves heterogeneous binding sites and sequential stacking of metal ions. The Bio‐H still removed the metal ions after the 3rd cycle of adsorption‐regeneration.

Urban infrastructure shapes environmental quality not only through its form and function but also through the materials from which it is built. Asphalt is a prominent example: heat, solar radiation, and aging can amplify emissions from this climate‐responsive, chemically active material. However, urban air‐quality frameworks continue to treat these emissions as diffuse ambient burdens, overlooking their role as localized, episodic exposure events with potential implications for community health, occupational safety, and functional performance. This review synthesizes evidence across materials science, atmospheric chemistry, exposure science, toxicology, and human factors to propose a unified, human‐centered monitoring framework that links asphalt emission dynamics to exposure conditions, biological relevance, and functional human‐response endpoints. We identify three gaps that motivate the framework: (1) weak integration between emission chemistry, chemical changes and reactions, and real‐world exposure conditions, (2) insufficient monitoring resolution to capture short‐duration, source‐proximate, high‐intensity events, and (3) limited coupling of exposure data with repeated human response measurements and functional endpoints such as symptoms, perception, cognition, and behavior. By organizing these gaps within a single monitoring logic, the framework can guide future efforts to identify who is exposed, under what environmental conditions, and with what potential health or functional relevance. This structure provides a pathway toward more health‐protective infrastructure design, construction practices, and governance. This need is particularly relevant in rapidly urbanizing, arid, and hot‐climate regions, where persistent thermal forcing may amplify both material emissions and human exposure. Although the evidence synthesized in this review focuses primarily on asphalt, the source–exposure–response framework may be transferable to other climate‐sensitive infrastructure materials as part of broader efforts to advance healthier, more adaptive, and more sustainable urban environments.