Abstract: Valparaiso, a central-southern region in Chile, has one of the highest rates of wildfire occurrence in the country. The constant threat of fires is mainly due to its highly flammable forest plantation, composed of 97.5% Pinus radiata and Eucalyptus globulus. Fuel moisture content is one of the most relevant parameters for studying fire spreading and risk, and can be estimated from the reflectance of leaves in the short wave infra-red (SWIR) range, not easily available in most vision-based sensors. Therefore, this work addresses the problem of estimating the water content of leaves from the two previously mentioned species, without any knowledge of their spectrum in the SWIR band. To this end, and for validation purposes, the reflectance of 90 leaves per species, at five dehydration stages, were taken between 350 nm and 2500 nm (full spectrum). Then, two machine-learning regressors were trained with 70% of the data set to determine the unknown reflectance, in the range 1000 nm-2500 nm. Results were validated with the remaining 30% of the data, achieving a root mean square error less than 9% in the spectrum estimation, and an error of 10% in spectral indices related to water content estimation. (C) 2020 IAgrE. Published by Elsevier Ltd. All rights reserved.

Abstract: This paper reviews the current knowledge of hydrological processes in Chilean temperate forests which extend along western South America from latitude 29 degrees S to 56 degrees S. This geographic region includes a diverse range of natural and planted forests and a broad sweep of vegetation, edaphic, topographic, geologic, and climatic set-tings which create a unique natural laboratory. Many local communities, endangered freshwater ecosystems, and downstream economic activities in Chile rely on water flows from forested catchments. This review aims to (i) provide a comprehensive overview of Chilean forest hydrology, to (ii) review prior research in forest hydrology in Chile, and to (iii) identify knowledge gaps and provide a vision for future research on forest hydrology in Chile. We reviewed the relation between native forests, commercial plantations, and other land uses on water yield and water quality from the plot to the catchment scale. Much of the global understanding of forests and their relationship with the water cycle is in line with the findings of the studies reviewed here. Streamflow from forested catchments increases after timber harvesting, native forests appear to use less water than plantations, and streams draining native forest yield less sediment than streams draining plantations or grassland/shrublands. We identified 20 key knowledge gaps such as forest groundwater systems, soil-plant-atmosphere interactions, native forest hydrology, and the effect of forest management and restoration on hydrology. Also, we found a paucity of research in the northern geographic areas and forest types (35-36 degrees S); most forest hydrology studies in Chile (56%) have been conducted in the southern area (Los Rios Region around 39-40 degrees S). There is limited knowledge of the geology and soils in many forested areas and how surface and groundwater are affected by changes in land cover. There is an opportunity to advance our understanding using process-based investigations linking field studies and modeling. Through the establishment of a forest hydrology science “society” to coor-dinate efforts, regional and national-scale land use planning might be supported. Our review ends with a vision to advance a cross-scale collaborative effort to use new nation-wide catchment-scale networks Long-term Ecosystem Research (LTER) sites, to promote common and

Abstract: Irrigation scheduling based on soil water content (Ow) sensors requires that Ow be maintained within a range (management lines) that is optimal for plant growth. The lower limit or “breaking point ” is determined following the soil water content dynamics on the transition of a rapid rate of depletion to a slower, under similar reference evapotranspiration. Although this criterion is practical, its implementation should be validated with plant water status measurement that contemplate weather condition, such as stem water potential “non-stressed ” baseline (Tx as a function of vapor-pressure deficit (VPD) in Ow conditions that do not limit yield). A study was con-ducted on a mature cv. 'Hass' avocado orchard in Central Chile during two seasons. There were 5 irrigation treatments: T1, Control; T2 and T3 with 29% less and 25% more of what was applied in T1, respectively; T4 and T5 same as Control until first and second fruit drop abscission, respectively, and then with 29% less. T1 trees were irrigated using a continuous frequency domain reflectometry (FDR) probe to maintain the root zone be-tween field capacity and the breaking point. There was biweekly monitoring of the Ow prior to irrigation, Tx and VPD. The Tx decline proportional to the intensity and the timing of water restriction; however, no treatment affected the crop load in either season. T2 did not show significant detrimental in fruit size, production and maturation, despite that frequently reached water content levels at the limit of the breaking point, and showed lower levels of stem water potential than Control, being the treatment with the highest water productivity. The results confirm that breaking point is an effective criterion to establish irrigation management. Additionally, when comparing the baseline for our non-stressed trees with a baseline from full irrigation treatments obtained from the literature, 30% water savings were achieved.

Abstract: The development and stability of aerobic granular sludge (AGS) was studied in two Sequencing Batch Reactors (SBRs) treating fish canning wastewater. R1 cycle comprised a fully aerobic reaction phase, while R2 cycle included a plug-flow anaerobic feeding/reaction followed by an aerobic reaction phase. The performance of the AGS reactors was compared treating the same effluents with variable salt concentrations (4.97-13.45 g NaCl/L) and organic loading rates (OLR, 1.80-6.65 kg CODs/(m(3).d)). Granulation process was faster in R2 (day 34) than in R1 (day 90), however the granular biomass formed in the fully aerobic configuration was more stable to the variable feeding composition. Thus, in R1 solid retention times (SRT), up to 15.2 days, longer than in R2, up to 5.8 days, were achieved. These long SRT5 values helped the retention of nitrifying organisms and provoked the increase of the nitrogen removal efficiency to 80% in R1 while it was approximately of 40% in R2. However, the presence of an anaerobic feeding/reaction phase increased the organic matter removal efficiency in R2 (80-90%) which was higher than in R1 with a fully aerobic phase (75-85%). Furthermore, in R2 glycogen-accumulating organisms (GAOs) dominated inside the granules instead of phosphorous-accumulating organisms (PADS), suggesting that GAOs resist better the stressful conditions of a variable and high-saline influent. In terms of AGS properties an anaerobic feeding/reaction phase is not beneficial, however it enables the production of a better quality effluent. (C) 2019 Elsevier Ltd. All rights reserved.

Abstract: Water scarcity is becoming a global challenge to attempts to narrow the water demand-supply gap. To overcome this problem, it is sensible to consider alternative technologies that can exploit non-conventional water resources. The choice of such technologies should be, however, carefully analyzed, because any choice might be unfeasible from an economic point of view. In this work, a methodology to select the most appropriate non-conventional water resource, out of municipal wastewater and seawater, was proposed. Specifically, we attempted to determine which alternative provides cheaper water supply and production costs for domestic uses, depending on the wastewater treatment system used and the water plant capacity. The production of water under three scenarios was analyzed: (i) a city that has a conventional wastewater treatment plant (WWTP); (ii) a city that uses primary treatment and submarine outfalls to treat municipal wastewater; (iii) seawater desalination. The proposed methodology was tested in Chilean cities that are located in areas where water is a scarce resource. The results showed that the reuse of municipal wastewater represents a cost-competitive alternative to seawater desalination, mainly when municipal wastewater is treated in a conventional WWTP and when water flow demand is higher than 1500 m(3)/d. In contrast, seawater desalination becomes more profitable than wastewater reuse when the treatment of municipal wastewater is based on the use of submarine outfalls. This study provides a useful economic tool for promoting municipal wastewater reuse as a non-conventional water source for supplying water to cities that suffer from water scarcity in Chile and in similar areas of the world.

Abstract: Aerobic granular sludge represents an interesting approach for simultaneous organic matter and nitrogen removal in wastewater treatment plants. However, the information about microbial communities in aerobic granular systems dealing with industrial wastewater like pig slurry is limited. Herein, bacterial diversity and dynamics were assessed in a pilot scale plant using aerobic granular sludge for organic matter and nitrogen elimination from swine slurry during more than 300 days. Results indicated that bacterial composition evolved throughout the operational period from flocculent activated sludge, used as inoculum, to mature aerobic granules. Bacterial diversity increased at the beginning of the granulation process and then declined due to the application of transient organic matter and nitrogen loads. The operational conditions of the pilot plant and the degree of granulation determined the microbial community of the aerobic granules. Brachymonas, Zoogloea and Thauera were attributed with structural function as they are able to produce extracellular polymeric substances to maintain the granular structure. Nitrogen removal was justified by partial nitrification (Nitrosomonas) and denitrification (Thauera and Zoogloea), while Comamonas was identified as the main organic matter oxidizing bacteria. Overall, clear links between bacterial dynamics and composition with process performance were found and will help to predict their biological functions in wastewater ecosystems improving the future control of the process. (c) 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1212-1221, 2016

Abstract: Aerobic granular sequencing batch reactors (SBRs) are usually inoculated with activated sludge which implies sometimes long start-up periods and high solids concentrations in the effluent due to the initial wash-out of the inoculum. In this work, the use of aerobic mature granules as inoculum in order to improve the start-up period was tested, but no clear differences were observed compared to a reactor inoculated with activated sludge. The effect of the aeration rate on both physical properties of granules and reactor performance was also studied in a stable aerobic granular SBR. The increase of the aeration flow rate caused the decrease of the average diameter of the granules. This fact enhanced the COD and ammonia consumption rates due to the increase of the DO level and the aerobic fraction of the biomass. However, it provoked a loss of the nitrogen removal efficiency due to the worsening of the denitrification capacity as a consequence of a higher aerobic fraction.

Abstract: Ocean Acidification (OA) can have pervasive effects in calcifying marine organisms, and a better understanding of how different populations respond at the physiological and evolutionary level could help to model the impacts of global change in marine ecosystems. Due to its natural geography and oceanographic processes, the Chilean coast provides a natural laboratory where benthic organisms are frequently exposed to diverse projected OA scenarios. The goal of this study was to assess whether a population of mollusks thriving in a more variable environment (Talcaruca) would present higher phenotypic plasticity in physiological and morphological traits in response to different pCO(2) when compared to a population of the same species from a more stable environment (Los Molles). To achieve this, two benthic limpets (Scurria zebrina and Scurria viridula) inhabiting these two contrasting localities were exposed to ocean acidification experimental conditions representing the current pCO(2) in the Chilean coast (500 mu atm) and the levels predicted for the year 2100 in upwelling zones (1500 (mu atm). Our results show that the responses to OA are species-specific, even in this related species. Interestingly, S. viridula showed better performance under OA than S. zebrina (i.e., similar sizes and carbonate content in individuals from both populations; lower effects of acidification on the growth rate combined with a reduction of metabolism at higher pCO2). Remarkably, these characteristics could explain this species' success in overstepping the biogeographical break in the area of Talcaruca, which S. zebrina cannot achieve. Besides, the results show that the habitat factor has a strong influence on some traits. For instance, individuals from Talcaruca presented a higher growth rate plasticity index and lower shell dissolution rates in acidified conditions than those from Los Molles. These results show that limpets from the variable environment tend to display higher plasticity, buffering the physiological effects of OA compared with limpets from the more stable environment. Taken together, these findings highlight the key role of geographic variation in phenotypic plasticity to determine the vulnerability of calcifying organisms to future scenarios of OA.

Abstract: The recycling of discarded membranes (end-of-life) represents a relevant alternative for sustainability of reverse osmosis (RO) desalination plants in the context of circular economy. This work evaluated the feasibility of using discarded commercial RO membranes in the treatment of domestic secondary wastewater to obtain water with a certain standard quality. Crossflow filtration tests were conducted to evaluate desalination and wastewater filtration performance at different operating pressures on RO membranes discarded from desalination plans at different working positions (primary M1; secondary M2). The standard manufacturer desalination tests showed a superior performance on M1 membranes, in terms of rejection (similar to 25 LMH, 97%), compared to M2 (similar to 33 LMH, 50%); both having a lower performance than a standard membrane (38 LMH +/- 15%; 99.6%). The failure is sufficient for discarding due to loss of lifespan. Moreover, in wastewater filtration tests using the secondary clarifier outlet effluent from a WWTP at different working pressures, both types of membranes were shown to be effective, with degrees of performance highly dependent on the working pressure. Thus, the operating values of permeate flux/salt rejection were between 56 and 59 LMH/ 96-97% for 600 psi: 33-34 LMH/ 94-96% for 300-psi and in the range of 10-11 LMH/ 90-94% for 80-psi test. Surface characterization of the membrane showed a pressure-related increase in fouling and bacterial adhesion post-filtration. Finally, the operating performance was verified in M1 wastewater filtration at 300 psi over long times (14 h), yielding stable and promising values (similar to 27 LMH; 96%). The permeate obtained has a low concentration of fecal coliforms (< 2 MPN/ 100 mL, 99.99% removal) and meets local standards for irrigation and drinking water in terms of conductivity, phosphorus and nitrogen concentration in treated water. (c) 2022 Institution of Chemical Engineers.

Abstract: The wastewater from the cookers of a tuna-canning plant was used as feedstock for the process. It was acidified in a continuous stirred tank reactor (CSTR) of 1.5 L to produce a mixture of volatile fatty acids (VFAs). The effluent contained 28.3 & PLUSMN; 8.7 g CODS/L and 25.0 & PLUSMN; 4.6 g CODVFA/L, 4.4 & PLUSMN; 1.6 g NH4+/L, and 10.9 & PLUSMN; 4.0 g Na+/L, which corresponds to about 28 g NaCl/L approximately. This was used to feed a PHA production system. The enriched MMC presented a capacity to accumulate PHAs from the fermented tuna wastewater. The maximum PHA content of the biomass in the fed-batch (8.35 wt% PHA) seemed very low, possibly due to the variable salinity (from 2.2 up to 12.3 g NaCl/L) and the presence of ammonium (which promoted the biomass growth). The batch assay showed a PHA accumulation of 5.70 wt% PHA, but this is a much better result if the productivity of the reactor is taken into account. The fed-batch reactor had a productivity of 10.3 mg PHA/(L h), while the batch value was about five times higher (55.4 mg PHA/(L h)). At the sight of the results, it can be seen that the acidification of fish-canning wastewater is possible even at high saline concentrations (27.7 g NaCl/L). On the other hand, the enrichment and accumulation results show us promising news and which direction has to be followed: PHAs can be obtained from challenging substrates, and the feeding mode during the accumulation stage has an important role to play when it comes to inhibition.