Envisioning a sustainable biorefinery requires reliable information on the sustainable availability of biomass, optimal plant location and delivered cost. In this paper, we have developed an integrated Geographic Information System (GIS) based sustainable biomass assessment, site optimization and supply logistics cost model to assess the spatial and temporal availability of crop residues, to identify optimal plant sites and to calculate the delivered cost. The grid-level (30x30m) assessment model was developed for crop residues using three primary sustainability indicators: (1) Soil Erosion (SE), (2) Soil Conditioning Index (SCI) and (3) Crop residue yield ≥ 2.5 dry Mg/ha. The Artificial Neural Networks (ANNs) prediction models for each indicator were developed and implemented in the GIS platform to estimate SE and SCI values to assess sustainably available crop residues. A multi-criteria geospatial analysis was used to identify suitable plant sites. GIS-based location-allocation model was used to site biorefineries/plants at optimal locations and generate feedstock supply curves. The developed model was demonstrated with the sustainable assessment of cotton stalk (CS) to produce fuel pellets in the study region (Georgia, USA). The model has estimated that about 1.6 million dry Mg of CS is available

This study addressed the potential of reduced prebloom irrigation, referred to as primed acclimation (PA), to increase agricultural water-use efficiency (WUE) using a soil-moisture-based irrigation scheduling system in cotton (Gossypium hirsutum L.). To address this, a study was conducted near Camilla, GA, under a variable-rate, center-pivot irrigation system using a Watermark-based automated soil moisture sensing approach to measure soil water potential (SWP) and impose varying irrigation scheduling treatments during the prebloom stage of development. Early season thresholds were −20 (Treatment 1), −40 (Treatment 2), −70 (Treatment 3), to −100 kPa (Treatment 4) prior to flowering. Reductions in prebloom irrigation of up to 17% were noted in this study for the driest thresholds (−100 kPa) with no reduction in lint yield relative to the −20 and −40 kPa thresholds. In some cases, prebloom irrigation was eliminated completely in the drier prebloom threshold treatments with no appreciable yield reductions. In rainfed treatments, episodic drought during flowering (2014) limited plant growth and node production, hastened cutout, decreased boll numbers per plant, produced a more compact boll distribution on the plant, and decreased yield and WUE relative to irrigated treatments. In contrast, season-long rainfed treatments exhibited the highest WUE in 2015 (a wet season). The results of this study conclude that prebloom irrigation thresholds between −70 and −100 kPa appear to be viable for use in a sensor-based PA irrigation scheduling system, whereas episodic drought coinciding with flowering represents a major threat to yield stability and WUE for cotton production in the southeastern United States.

To better understand the fate of per-and polyfluoroalkyl substances (PFAS) during conventional and advanced wastewater treatment, 42 PFAS (C3−C14 perfluorocarboxylic acids (PFCAs), C3−C10 perfluorosulfonic acids (PFSAs), per-and polyfluoroethers, and perfluoroalkyl acid (PFAA) precursors) were investigated through the treatment trains at two municipal wastewater treatment plants (WWTPs) using a targeted analysis, the total oxidizable precursor (TOP) assay, and the estimation of partitioning to sludge. Short-chain (C3−C7) PFAAs were found in higher concentrations in wastewater samples, while long-chain (≥C8) PFAAs dominated in sludge samples. PFAA concentrations were elevated by the wastewater treatment processes, particularly after biological treatment (191.3 and 185.1% increases of PFAAs at WWTP-A and B). After TOP oxidation, PFCAs, particularly short-chain ones, increased considerably (up to 311.4 and 409.3% increases of PFCAs at WWTP-A and B). The study results indicated that the transformation of precursors into shorter chain PFAAs by biological treatment and the partitioning of longer chain PFAS into sludge streams are key factors determining the fate of PFAS in WWTPs. With the increasing impact of shortchain PFAS over time, future research should focus on the evaluation of the fate and distribution of historical and emerging PFAS in WWTPs. KEYWORDS: (ultra)short-chain PFAS, PFAA precursors, municipal wastewater treatment plant, biological treatment, advanced treatment processes

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