Most extreme natural hazard mitigation projects are analyzed using monetary indices, thereby not fully accounting for social benefits. Rigorous modeling and quantification of nonmonetary social impacts are needed to effectively estimate project benefits. In the case of habitation this requires modeling the infrastructure systems that provide critical products and services. This study proposes and demonstrates a system dynamics-based model to quantify the habitation-related impacts of mitigation projects by simulating the availability of habitable residential units based on the performance of critical internal infrastructure systems (CIIS). The model was applied to the Halls Bayou watershed in Houston, Texas, under various storm scenarios, with and without a planned mitigation project. Simulation results show that, in the case study, wastewater treatment outages primarily drive initial habitation loss, while residential shelter availability governs recovery duration and habitation loss scale. In a 500-year storm scenario, the mitigation project decreased total habitation loss scale by 100,320 residence-days (18%) and shortened recovery duration by 14 days (9%). The model structure helps explain these results. This dynamic modeling approach and model offer a new tool for disaster planning and management by facilitating the incorporation of social impacts into mitigation project analyses.
Communities implementing direct potable reuse (DPR) need to prioritize recruitment, retention, and continuing education of operators.Filling knowledge gaps in risk-based framework assumptions and educating regulators about the nuances of these frameworks can reduce DPR regulatory angst.Public-facing monitoring efforts, facility tours, and construction-process involvement can bolster support for DPR, which can provide unique economic and societal benefits to communities.Community education on DPR water quality should be nuanced to avoid introducing misconceptions about conventional water quality.
This study provides a systematic evaluation of sediment-derived inocula for anaerobic co-digestion of sewage sludge and landfill leachate. Three inocula, including conventional anaerobic digester (AD, campus pond sediment (CP), and landfill pond sediment (LP) were evaluated across varying F/M (Food/Microorganism) and LL/MS (Landfill Leachate/Mixed Sludge) mixing ratios. The objective was to assess how inoculum origin influences microbial assembly and its relationship with methane productivity and process stability. Campus pond sediment (CP) achieved the highest biogas production (492.4 mL biogas g-1 VSadded at F/M = 2 and 30% LL/MS), outperforming AD and LP by 4.9% and 15.9%, respectively, while landfill pond sediment displayed the greatest chemical oxygen demand removal (67.3%). Free ammonia concentrations remained < 40 mgL-1, confirming non-inhibitory conditions, and metal concentrations were well below biosolids regulatory thresholds. Microbial analysis revealed clear inoculum-dependent divergence. Bacterial communities shifted toward increased Firmicutes by Day 30, indicating enhanced hydrolysis and fermentation. Archaeal structure remained highly stable and hydrogenotrophic, dominated by Methanospirillum, Methanobacterium, and Candidatus Methanofastidiosum, indicating that hydrogenotrophic methanogenesis was likely a major CH4 producing pathway. Functional gene predictions showed enrichment of KEGG (Kyoto Encyclopedia of Genes and Genomes) modules associated with carbohydrate and amino acid metabolism in CP, while LP exhibited higher representation of stress-tolerance and xenobiotic-processing genes. Overall, sediment-derived inocula, particularly CP, enhanced methane production and system stability, with inoculum origin identified as the dominant factor governing microbial structure and process performance. These findings highlight sediment inocula as promising alternatives to conventional AD sludge.
Potable reuse is a significant component that supports the development of resilient water supplies globally. To protect public health and to support the uptake of potable reuse, treatment barrier performance must be validated for the removal of chemical and microbial contaminants. Currently, there are variations between existing potable reuse regulations, validation guidelines, and validation protocols, as well as considerable gaps in the scientific knowledge needed to develop, extend, and harmonize these guidelines and protocols. The WaterVal framework, originally developed in Australia to streamline the validation of water reuse treatment barriers, has the potential to fill this gap and serve as a universal umbrella program, providing a template for the development of treatment barrier validation protocols. WaterVal specifies nine elements that must be addressed to ensure consistency and uniformity in treatment barrier performance when targeting pathogen and chemical contaminant removal. CalVal, an initiative to develop guidance for potable reuse in the state of California (USA), has built on these efforts to provide best practices for the design, operation, and reporting of various treatment barriers used in potable reuse schemes. Collaborative efforts between CalVal and WaterVal will help identify and address knowledge gaps to inform proposed validation frameworks and operational recommendations.
