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Open research questions in Wastewater Treatment and Reuse

46 unresolved questions extracted from the limitations and future-work sections of 518 Wastewater Treatment and Reuse papers in our library. Each links back to the study that raised it.

What the literature leaves open

  • High capital costs, - Complex operational requirements for coupled systems, - Institutional gaps in regulation and cross-sectoral coordination, - Variable inflow conditions

    A multi-criteria decision analysis for sustainable resource recovery from municipal wastewater in Zvishavane, Zimbabwe using the NEREUS DST · 2026 · DOI

  • Low frequencies of scheduled desludging. Limited public awareness regarding safe sanitation practices. Limited integration between government and private sludge transportation.

    INFRASTRUCTURE PERFORMANCE ANALYSIS OF THE ON-SITE DOMESTIC WASTEWATER MANAGEMENT SYSTEM IN BANDA ACEH · 2026 · DOI

  • The high levels of organic matter and suspended solids in cracker-industry wastewater can exceed environmental quality standards. The treatment of cracker-industry wastewater requires effective, economical, and environmentally friendly methods. The scalability and applicability of phytoremediation for cracker-industry wastewater need to be investigated.

    Wastewater Treatment of the Cracker Industry Using the Phytoremediation Method with Water Lettuce (Pistia stratiotes) Plants · 2026 · DOI

  • Corrosion risk in the hybrid cooling system. Limited access to fresh water for cooling systems. Need for predictive maintenance to prevent equipment failure.

    Assessment of Water Chemistry in the Hybrid Cooling System of a Thermal Power Plant Using ICP-MS Analysis and Comparison with EPRI Guidelines · 2026 · DOI

  • Few studies have addressed field-based investigations of dry-wet hybrid systems. There is a lack of knowledge on the water chemistry and corrosion behavior in hybrid cooling systems.

    Assessment of Water Chemistry in the Hybrid Cooling System of a Thermal Power Plant Using ICP-MS Analysis and Comparison with EPRI Guidelines · 2026 · DOI

  • Water scarcity. Inadequate sewage treatment. Limited access to basic services such as sanitation.

    From sewage to fertile land: social technologies and wastewater quality in semi-arid region of Rio Grande do Norte · 2026 · DOI

  • The effects of wastewater irrigation on edible vegetable crops remain context-dependent. There is a need to understand the impacts of wastewater irrigation on crop growth and quality.

    Differential morphological, physiological, and antioxidant responses of Allium cepa and Allium sativum to untreated municipal wastewater · 2026 · DOI

  • The study identifies a gap in understanding the seasonal irrigation suitability of drain water. The study highlights the need for integrated approaches to evaluate drain water quality.

    Decoding seasonal irrigation suitability of drain water using integrated indexical, statistical, graphical and machine learning approaches · 2026 · DOI

  • The study only collected samples from Mymensingh City. The sample size was limited to 10 raw greywater samples with three replications each.

    Greywater Quality Assessment and Reuse Potential in Mymensingh: Towards Sustainable Urban Water Use · 2026 · DOI

  • Further studies should investigate the effectiveness of different treatment methods for greywater recycling. Research should focus on scaling up greywater reuse initiatives. Studies should evaluate the economic and environmental benefits of greywater reuse.

    Greywater Quality Assessment and Reuse Potential in Mymensingh: Towards Sustainable Urban Water Use · 2026 · DOI

  • The lack of investments in wastewater infrastructure, adoption of innovative sanitation systems, environmental education, and robust policy frameworks limits the implementation of sustainable wastewater treatment technologies. Rapid urbanization, climate change, industrial pollution, and population growth threaten global water security.

    Water and Wastewater Treatment Technologies: Sustainable Approaches for Clean Water Access and Environmental Protection · 2026 · DOI

  • Future research should investigate the long-term effects of blending on water quality and security. Future research should explore the application of blending strategies in other water-stressed regions.

    Sustaining drinking water quality in water-stressed regions: a case study of the distribution network in Mpumalanga · 2026 · DOI

  • The study identifies a gap in the understanding of the complex dynamics of water quality in water-stressed regions. The study highlights the need for targeted strategies to ensure water security through the sustainability of water distribution networks.

    Sustaining drinking water quality in water-stressed regions: a case study of the distribution network in Mpumalanga · 2026 · DOI

  • There is a need for a decision support tool to aid in the selection of treatment trains for resource recovery from municipal wastewater. The existing decision support tools do not evaluate the interchanges and connections of different sustainability indicators. There is a lack of studies on the application of the NEREUS DST framework in a Multi-Criteria Decision Analysis for resource recovery from municipal wastewater.

    A multi-criteria decision analysis for sustainable resource recovery from municipal wastewater in Zvishavane, Zimbabwe using the NEREUS DST · 2026 · DOI

  • Existing water management practices are insufficient to address microbial contamination and water quality issues. There is a need for sustainable and accessible treatment systems. The study aims to address the issue of water quality in educational institutions.

    Design and Development of a Solar-powered Water Purifier Prototype · 2026 · DOI

  • This study was limited by the small number of sampling locations and the short duration of testing. Water quality assessment was conducted using field-based bacterial testing kits and heavy metal test strips rather than laboratory-grade analytical methods. Consequently, the results are based on semi-quantitative and qualitative measurements rather than precise quantitative analyses. The scope of analysis was limited to selected heavy metal indicators and the presence or absence of bacterial contamination. It did not include identification of specific bacterial species or measurement of exact contaminant concentrations. Bacterial testing was restricted to two testing periods due to the 48-hour incubation requirement of the testing kit, which limited the number of repeated trials within the study timeframe. This reduced the extent of replication that could have strengthened result reliability. In addition, the study did not assess long-term operational performance, maintenance requirements, energy efficiency, treatment cost, or system scalability under continuous-use conditions. Therefore, the findings primarily reflect short-term performance under controlled experimental conditions. CONCLUSION This study developed a functional solar-powered water purifier prototype integrating renewable energy with a multi-stage water treatment system. Test results indicated reductions in microbiological contamination, with no detectable bacterial presence in treated samples. Improvements were also observed in selected chemical parameters, particularly the non-detection of cadmium after treatment. However, zinc remained detectable in one treated sample, indicating limited removal efficiency for certain dissolved substances. Interpretation of the findings is constrained by the small sample size, short testing period, and use of field-based testing methods instead of laboratory-grade analyses. Overall, the results indicate improved water quality following treatment, particularly in terms of microbiological parameters. The findings support further investigation of solar-powered purification systems for application in educational settings. Future research should involve larger sample sizes, laboratory-based analyses, extended operational testing, and comparative evaluation with established water treatment systems. ACKNOWLEDGEMENT The researchers express gratitude to all individuals who contributed to the completion of the study entitled “Design and Development of a Solar-Powered Water Purifier Prototype.” Above all, the researchers thank the Almighty God for providing wisdom, guidance, and strength throughout the course of this research. The researchers extend appreciation to the research adviser, Sir Oscar Romero Jr., for constructive feedback, guidance, and continuous support that contributed to the improvement of the study. Page 1868 www.rsisinternational.org INTERNATIONAL JOURNAL OF LATEST TECHNOLOGY IN ENGINEERING, MANAGEMENT & APPLIED SCIENCE (IJLTEMAS) ISSN 2278-2540 | DOI: 10.51583/IJLTEMAS | Volume XV, Issue V, May 2026 REFERENCES 1. Ahmad, A., Khan, Z. M., & Farid, H. U. (2024). A potential solution for clean water supply: Multi-effect solar still and water quality analysis. Water Supply, 24(2), 329–340. https://doi.org/10.2166/ws.2024.003 2. Ahmed, R., Ahamed, E., & Islam, F. (2024). IoT-based solar-powered water purification systems. University-Bangladesh.

    Design and Development of a Solar-powered Water Purifier Prototype · 2026 · DOI

  • Routine logs and scheduled laboratory testing for turbidity and microbiological indicators are required to verify long-term water safety. Staged monitoring improvements as the system continues operating.

    Ultrafiltration-based drinking water service for SDG 6 in Pulau Kemarau · 2026 · DOI

  • The lack of access to safe drinking water in river-dependent communities. The need for decentralized drinking-water service points that can operate at low cost.

    Ultrafiltration-based drinking water service for SDG 6 in Pulau Kemarau · 2026 · DOI

  • The study identifies a research gap in the assessment of wastewater treatment efficiency in the Lake Czorsztyn region. The study highlights the need for improved wastewater treatment efficiency in the region to protect the aquatic environment.

    Analysis of wastewater treatment efficiency in the region of Lake Czorsztyn · 2026 · DOI

  • There is a need for standardization of methods in WBE. There is a lack of understanding of the stability of analytes in sewer systems.

    Wastewater‑Based Epidemiology in the Monitoring of Community Health and Environmental Exposure · 2026 · DOI

  • There is a lack of data on bromide concentrations in Estonian WWTP effluents. The use of ozonation for micropollutant removal requires further research.

    Bromides in treated wastewater: limiting the choice of quaternary wastewater treatment technologies for residual micropollutant removal. An Estonian case study · 2026 · DOI

  • The gap is in understanding the socio-ecological and economic benefits of managed reuse in an arid agricultural system. The effects of salinity on different rootstocks are not well understood.

    Reframing Reclaimed Wastewater as a Resource: Socio-Ecological and Economic Benefits of Managed Reuse in an Arid Agricultural System · 2026 · DOI

  • The specificity of the formation of filtration waters can differ significantly. There is a need to develop a controlled mechanism for the formation of soil layers for more complex nature-like systems.

    The mechanism of wastewater formation from artificial green areas in urbanized territories · 2026 · DOI

  • The lack of access to safe drinking water in many areas, particularly in rural Indonesia, where bore wells or groundwater are vulnerable to contamination by heavy metals. The need for low-cost, locally available filtration media for clean water treatment.

    Comparative Effectiveness of Coconut Shell Charcoal and Rice Husk Ash as Adsorbents in Filtration Systems for Iron (Fe) and Manganese (Mn) Removal from Groundwater · 2026 · DOI

  • Conventional upgrades of WWTPs require substantial land and capital investment. There is a need for a cost-effective and environmentally friendly approach for upgrading overloaded WWTPs.

    Advanced Primary Filtration (APF) Process in Wastewater Treatment: A Techno-Economic and Environmental Assessment · 2026 · DOI

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46 open questions have been extracted from the limitations and future-work passages of 518 Wastewater Treatment and Reuse papers in our library. Each one below links back to the study that raised it, so you can read the original claim in context.

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