Hydrothermal carbonization (HTC) is a promising process for the upgrading of wet biomass residues. Models of HTC processes, in particular at continuous pilot-scale, are needed to move HTC from lab-scale to industrial scale. This study presents a process model for mild HTC, dewatering and conversion to intermediate energy carriers (bio-pellets and biogas for power and/or heat production) of three wet biomass residue streams: paper sludge, olive pomace and orange peels, based on lab- and pilot-scale experiments. In addition, the process energy efficiency and feedstock utilization of the HTC process is calculated and compared with conventional treatment options for the chosen residues, i.e., direct anaerobic digestion (olive pomace, orange peels) or combustion after conventional dewatering (paper sludge). The process model indicates that the HTC pilot-scale process is much more efficient in terms of feedstock utilization to produce heat and/or power than the reference scenarios. The process energy efficiency of the HTC process (pilot-scale) was calculated to be 26%, 63% and 40% for paper sludge, olive pomace and orange peel feedstocks, respectively. For all feedstocks, both the solid and liquid-generated products are equally important for improving the overall process energy efficiency. This study demonstrates the potential benefits of HTC processes for upgrading wet biomass waste streams based on continuous pilot-scale data.

The ever-increasing volumes of food waste generated and the associated environmental issues require the development of new processing methods for these difficult waste streams. One of the technologies that can treat these waste streams directly is hydrothermal carbonization. In this work, olive pomace and orange peels were treated via a mild hydrothermal carbonization process (TORWASH®) in a continuous-flow pilot plant. For olive pomace, a solid yield of 46 wt% and a dry matter content of 58% for the solid press cakes were obtained during continuous operation for 18 days. For orange peels, the values were lower with 31 wt% solid yield and a 42% dry matter content during 28 days of continuous operation. These values corresponded fully with initial laboratory-scale batch experiments, showing the successful transformation from batch to continuous processing. The obtained hydrochar from both feedstocks showed an increase in higher heating value (HHV) and a significant reduction in ash content. Pellets produced from the solids met the requirements for industrial use, demonstrating a large increase in the deformation temperature and a significant reduction in the potassium and chlorine content compared to the original feedstock. These results indicate the excellent potential of these pellets for combustion applications.

Hydrothermal carbonization (HTC) of low quality, wet biogenic residues into intermediate bioenergy carriers can potentially contribute to a more flexible and stable renewable energy system and reduce environmental impacts compared to current residue disposal practices. This study quantifies the environmental impacts via life cycle assessment (LCA) of a novel hydrothermal process for the treatment on an industrial scale of application of three wet biogenic residues (paper bio-sludge, olive pomace, and orange peel) into bioenergy carriers, i.e., solid pellets and biogas. A comprehensive attributional cradle-to-gate life cycle assessment (LCA) was conducted; the life cycle impact assessment (LCIA) utilised the ReCiPe impact assessment method. A selection of 10 significant impact categories was prioritised. Reliability of this categorization was also ensured through a sensitivity analysis carried out using Monte Carlo simulation. Climate change, particulate matter formation and terrestrial acidification impact categories showed the highest reliability, while for freshwater ecotoxicity and freshwater eutrophication impact categories in the study suggest the need for more robust data and further investigation. The climate change impact category presents the following values, as kg CO2eq/tresidue: pulp and paper bio-sludge (PPB), 17.9; olive pomace (OP), −1290; orange peel (ORP), −1301. The LCA study compared electricity yields of the hydrothermal treatment process with conventional treatment processes for each of the target residue streams. The environmental performance of the proposed hydrothermal treatment benefits significantly from the combination of intermediate bioenergy carriers (pellets) from the solid fraction with biogas production from the liquid fraction. Avoided emissions due to the heat recovery provide further environmental benefits. The LCIA results show that the carbon footprint of the F-CUBED production system, as kgCO2eq/kWhe, accounts for –4.56, −0.63, and −0.25 for paper bio-sludge, olive pomace and orange peel, respectively.

Investigationof the environmental impacts of biobased componentsin polyurethane coatings using life cycle assessment methodology. Substituting fossil-based with biobased chemical buildingblockscan potentially decrease the environmental impact of polyurethane(PU) coating production. This study applies life cycle assessmentmethods in the early development of three processes that incorporatebiobased elements into PU coating production: a fully biobased coatingmade with organosolv lignin (OSL) and a biobased cross-linker fromvanillic acid (VA) and two hybrid coatings made with a fossil-basedcross-linker and either OSL or depolymerized OSL. Coatings with biobasedelements had impacts of 1.5, 2.6, and 19.9 kg CO2eq/kg(coating) for coatings made with OSL, depolymerized OSL, andthe fully biobased coating, respectively. Emissions are mostly associatedwith the fossil-based cross-linker in hybrid coatings and with solventsand heat needed for the production of the biomass-derived cross-linker.While this study demonstrates that the use of biobased compounds inhybrid coatings can reduce the environmental impacts of PU coatingsin comparison to fossil-based versions, additional development ofbiobased cross-linkers and research into end-of-life scenarios areneeded to further reduce the environmental impacts of biobased PUcoating production.

Hydrothermal treatment can convert paper mill biological (bio-) sludge waste into more energy-dense hydrochar, which can achieve energy savings and fossil CO2 emissions reduction when used for metallurgical applications. This study assesses the basic, combustion and safety performance of bio-sludge hydrochar (BSHC) to evaluate its feasibility of use in blast furnace injection processes. When compared to bituminous and anthracite coals, BSHC has high volatile matter and ash content, and low fixed carbon content, calorific value and ignition point. The Ti and Tf values of BSHC are lower and the combustion time longer compared to coal. The R0.5 value of BSHC is 5.27 × 10−4 s−1, indicating a better combustion performance than coal. A mixture of BSHC and anthracite reduces the ignition point and improves the ignition and combustion performance of anthracite: an equal mixture of BSHC and anthracite has a R0.5 of 3.35 × 10−4 s−1. The explosiveness of BSHC and bituminous coal is 800 mm, while the explosiveness of anthracite is 0 mm. A mixture of 30% BSHC in anthracite results in a maximum explosiveness value of 10 mm, contributing to safer use of BSHC. Mixing BSHC and anthracite is promising for improving combustion performance in a blast furnace while maintaining safe conditions.

Sludges from the papermaking industry represent a challenging residue stream that is difficult to dewater using conventional processes. The successful development and scale-up of innovative processes from lab- to pilot- to industrial-scale are required to tackle challenges for waste treatment, including paper sludges. Biological paper sludge was treated via a mild hydrothermal carbonization process (TORWASH®) to improve dewaterability of the sludge, including long-duration, continuous testing. Initial lab-scale experiments indicated the optimal treatment temperature for sludge dewatering was 190 °C. Dewaterability improved with increasing temperature, but the obtained solid yield decreased. Scaling-up to a continuous flow pilot plant required a temperature of 200 °C to achieve optimum dewatering. Pilot-scale hydrothermal treatment and dewatering resulted in solid cakes with an average dry matter content of 38% and a solid yield of 39%. This study demonstrates the benefits of hydrothermal carbonization for the dewatering of biological paper sludge without the use of dewatering aids such as fiber sludge or polyelectrolytes. The results also demonstrate the successful adaptation of a lab-scale batch process to a pilot-scale continuous flow process for hydrothermal carbonization of industrial wastewater sludge.

The present study investigated the impact of different loading approaches and microbial activity on the Natural Organic Matter (NOM) removal efficiency and capacity of ion exchange resins. Gaining further knowledge on the impact of loading approaches is of relevance because laboratory-scale multiple loading tests (MLTs) have been introduced as a simpler and faster alternative to column tests for predicting the performance of IEX, but only anecdotal evidence exists to support their ability to forecast contaminant removal and runtime until breakthrough of IEX systems. The overall trends observed for the removal and the time to breakthrough of organic material estimated using MLTs differed from those estimated using column tests. The results nonetheless suggest that MLTs could best be used as an effective tool to screen different ion exchange resins in terms of their ability to remove various contaminants of interest from different raw waters. The microbial activity was also observed to impact the removal and time to breakthrough. In the absence of regeneration, a microbial community rapidly established itself in ion exchange columns and contributed to the removal of organic material. Biological ion exchange (BIEX) removed more organic material and enabled operation beyond the point when the resin capacity would have otherwise been exhausted using conventional (i.e. in the absence of a microbial community) ion exchange. Furthermore, significantly greater removal of organic matter could be achieved with BIEX than biological activated carbon (BAC) (i.e. 56 +/- 7% vs. 15 +/- 5%, respectively) when operated at similar loading rates. The results suggest that for some raw waters, BIEX could replace BAC as the technology of choice for the removal of organic material. (C) 2018 Elsevier Ltd. All rights reserved.

A major drawback to ultrafiltration membrane operation for drinking water treatment is fouling, which results in lower water production and increased maintenance costs. The impact of different fouling mitigation strategies including, sparging conditions (duration and air flow rate) as well as phased in-line coagulation were investigated at pilot-scale. Unexpectedly, sparging during permeation and backwash resulted in a significantly higher rate of increase in irreversible resistance compared to Sparging only during backwash. Lower irreversible fouling observed without sparging during permeation was attributed to the formation of a protective layer on the membrane in the absence of sparging. Sparging at reduced air flow rates and intermittently, during the permeation cycle did not improve the irreversible resistance rate when compared to sparging only during backwash. The application of phased in-line coagulation to pre-coat membranes was also investigated. Coagulating for only the first half of the permeation cycle (phased coagulation) did not negatively impact membrane performance in terms of irreversible resistance and organics removal. Phased coagulation, which would lead to reduced coagulant and sludge disposal costs, appears to be a promising fouling control strategy. (C) 2017 Published by Elsevier B.V.

The natural organic matter (NOM) removal efficiency and regeneration behavior of ion-exchange filters with promoted biological activity (BIEX) was compared to operation where biological activity was suppressed (i.e. abiotic conditions). The impact of BIEX pre-treatment on fouling in subsequent ultrafiltration was also investigated. Biological operation enhanced NOM removal by approximately 50% due to an additional degradation of smaller humic substances, building blocks and low molecular weight acids. Promotion of biological activity significantly increased the time to breakthrough of the filters and, therefore, is expected to lower the regeneration frequency as well as the amount of regenerate of which to dispose. Pre-treatment using BIEX filters resulted in a significant decrease in total and irreversible fouling during subsequent ultrafiltration. The decrease was attributed to the effective removal of medium and low molecular weight NOM fractions. The results indicate that BIEX filtration is a robust, affordable and easy-to-operate pre-treatment approach to minimize fouling in ultrafiltration systems and enhance the quality of the produced permeate.

Surface shear stress induced by different air sparging regimes on a submerged hollow fiber ultrafiltration module with horizontally-oriented, densely packed fibers was characterized. Continuous and intermittent (cycling on and off) coarse bubbles (0.75–2.5mL), as well as large pulse bubble (150 and 500mL) sparging were considered for a range of air flow rates. The power required to induce surface shear stress on the surface of the hollow fibers was substantially lower when using large pulse bubble sparging compared to both continuous and intermittent coarse bubble sparging. Results indicated that the air flow required for pulse bubble sparging was more than 80% lower than that required for coarse bubble sparging to induce comparable surface shear stress (and corresponding fouling control). This study demonstrates the potential value and efficiency of pulse bubble air sparging as a fouling control option in densely packed hollow fiber membrane systems.

A pilot-scale study was performed to evaluate a coagulant dose which had been optimized for biopolymer (i.e., foulant) removal on subsequent ultrafiltration (UF) fouling, as well as disinfection by-product (DBP) precursor removal. Polyaluminum chloride (PACl) dosages were selected based on a point of diminishing returns for biopolymer removal (0.5 mg/L) and directly compared to that applied at full-scale (6 mg/L). Membrane fouling (reversible and irreversible) was measured as resistance increase over a 48 hour filtration period. DBP formation potential (total trihalomethanes (TTHMs), haloacetic acids (HAA 9 ) and total adsorbable organic halides (AOX)) were measured in both raw and treated waters. Results of the study indicate that application of a PACl dose optimized for biopolymer reduction (0.5 mg/L) resulted in 65% less irreversible UF fouling when compared to 6 mg/L. The addition of PACl prior to the membrane resulted in up to a 14% reduction in DBP precursors relative to the UF membrane alone. A similar level of DBP precursor reduction was achieved for both 0.5 and 6 mg/L dosages. The results have implications for cost savings, which may be realized due to decreased chemical use, as well as increased membrane life associated with lower irreversible fouling rates.

A bench-scale study was performed to optimize backwash frequency and air sparging conditions during ultrafiltration (UF) for drinking water treatment in order to minimize hydraulically irreversible fouling as well as operating and maintenance costs. Surface shear stress representing different air sparging conditions (continuous coarse bubble, intermittent coarse bubble, and large pulse bubble) was applied in combination with various backwash frequencies (0.5, 2, and 6 hours) during UF of two natural surface waters. Results indicated that air sparging during permeation with intermittent coarse or large pulse bubbles significantly reduced the rate of irreversible fouling. This allowed for longer permeation times (up to 6 hours) between backwashing, when compared to a baseline condition which assumed a 0.5 h-backwash frequency with no air sparging during permeation. As a result, operation and maintenance cost savings estimated at > $350,000/year for a 29 MLD membrane train could be realized. This study demonstrates that optimized air sparging could serve as a cost-effective UF fouling control strategy for drinking water production.

Air‐sparging and coagulation/flocculation were compared as fouling control strategies during ultrafiltration of surface waters. Fouling was assessed following coagulation (0.5 and 15 mg/L alum) and surface shear stress representative of different air‐sparging conditions: continuous coarse bubble, intermittent coarse bubble, and large pulse bubble. Results indicated that 0.5 mg/L of alum reduced membrane fouling, especially for waters with higher concentrations of organic matter (> 4 mg/L dissolved organic carbon). A 15‐mg/L alum dose did not significantly improve membrane performance relative to the low dose. Air‐sparging reduced fouling, but the benefits were not additive in combination with coagulation. Potential cost savings were calculated based on longer permeation times made possible by reduced fouling, and the value associated with water produced relative to energy costs (air‐sparging) and chemical costs (coagulant). For the water investigated, 0.5 mg/L of alum or large pulse bubble air‐sparging was optimal for membrane fouling control.

Coagulation as pre-treatment to ultrafiltration (UF) was optimized for the removal of biopolymers, i.e., a primary UF foulant, for three different natural water matrices. The impact of pre-coagulation on membrane reversible and irreversible fouling, as well as the retention of organic micropollutants, was investigated at bench scale. Jar test experiments indicated that the optimum alum dosage for removal of biopolymers, based on a point of diminishing returns analysis, was relatively low (0.5 mg/L as coagulant; 0.05 mg/L as Al3+). This dose was effective at reducing membrane reversible and irreversible fouling (up to 48%) for waters with higher concentrations of organics (>4 mg/L as DOC) over 24 h of permeation and backwash cycles. Biopolymers were identified as contributing to both reversible and irreversible fouling. The retention of organic micropollutants was relatively low for UF alone (<40%) and for coagulation alone (<30%) with higher removals observed in waters with greater concentrations of organic matter. For combined coagulation and UF, retention of some compounds increased by up to 25%. In general, retention was higher for neutral, more hydrophobic compounds (log K-ow > 2). This study demonstrates that a low dose of coagulant, optimized for biopolymer removal, may reduce membrane fouling and may provide value added for the retention of some organic micropollutants; however dosages depend on the specific water being treated, as well as treatment-related water quality targets. (C) 2014 Elsevier Ltd. All rights reserved.

This study investigated the impact of surface shear stress, to represent air sparging employed for fouling control, on the retention of organic micropollutants during ultrafiltration for drinking water treatment. The retention of 16 different pharmaceutically-active and endocrine disrupting compounds was examined during ultrafiltration of three natural surface waters (two lake, one river) under four different surface shear stress regimes: no shear stress, low peak shear stress (representative of continuous coarse bubble sparging), sustained peak shear stress (representative of intermittent coarse bubble sparging), and high peak shear stress (representative of large pulse bubble sparging). Results indicate that surface shear stress does impact the retention of emerging contaminants; however, it is dependent on water matrix and compound properties. The greatest retention of micropollutants was observed in waters with a higher concentrations of organic matter, and for conditions where no surface shear stress was applied (average 32% retention), and under conditions representative of large pulse bubble sparging (average 34% retention). The observed retention under conditions of no shear stress was likely due to a heavy fouling layer that altered the membrane selectivity and was able to entrap organic micropollutants of larger molecular weight. Under conditions that mimicked air sparging, increasing the shear stress (quantified as the root mean square applied shear) resulted in increased retention of organic micropollutants, particularly those that are neutral and hydrophobic in nature. This may be related to solute-solute complexes, which are kept in solution when shear stress is applied, or related to modification of the fouling layer by the shear stress induced onto the membrane surface. The results suggest that there may be value added with respect to removal of organic micropollutants, such as pharmaceuticals, when employing air sparging as a fouling control strategy during ultrafiltration. (C) 2013 Elsevier B.V. All rights reserved.

The effect of surface shear stress on membrane fouling during submerged hollow fiber ultrafiltration of three different surface waters (two lakes, one river) was investigated. Surface shear stresses that mimicked those induced when applying continuous and intermittent coarse bubble air sparging, large pulse bubble air sparging, as well as no air sparging were considered. The results suggest that fouling was mainly due to the accumulation of the biopolymer fraction of the natural organic matter present in the raw water. Inducing shear stresses onto the membrane surface significantly decreased the rate of membrane fouling (relative to no shear stress applied) in all waters tested. Of the shear stress conditions studied, that which mimicked large pulse bubble sparging had the greatest effect, reducing fouling by up to 80% when compared to conditions with no sparging applied. Conditions that mimicked intermittent and continuous coarse bubble fouling reduced the rate of fouling by up to 77 and 49%, respectively. These results suggest that the shear stresses induced by sparging can promote back transport of soluble organic material from the membrane surface. A semi-empirical relationship was developed to estimate the effect of raw water characteristics and applied sparging conditions on membrane fouling.

Wray, H. E. and Bayley, S. E. 2008. Nitrogen dynamics in floating and non-floating peatlands in the Western Boreal Plain. Can. J. Soil Sci. 88: 697-708. The overall objective of this study was to measure the major nitrogen pools and fluxes in nutrient- and peat-rich, vegetated marshes and fens surrounding shallow ponds in the Western Boreal Plain (WBP) of Canada. Within the same peatland-pond complex, marshes and fens did not differ from each other in major N fluxes and pool sizes; however, significant differences in N dynamics were measured between different peatland-ponds. Specifically, N cycling rates (gross and net mineralization) were Much greater in a floating peatland than in a non-floating peatland. Gross N mineralization rates were 59 and 453 mg N m(-2) d(-1) in the non-floating and floating peatlands, respectively. Gross ammonification rates were approximately 4-10 times net rates while gross nitrification rates were 500-800 times net rates, indicating rapid turnover of extractable inorganic N pools. Increased moisture and carbon in the floating peat supported higher microbial biomass and activity, however net primary production values were lower, presumably due to competition by microbes for available inorganic N. Monthly measurements of N fluxes were combined to provide an estimate of annual internal N cycling within marshes and fens surrounding shallow ponds in the WBP.

Western Boreal Plain peatlands can play an important role in the global nitrogen cycle by storing N in peat and potentially releasing large amounts of N to the atmosphere. In this study, biological denitrification rates were measured in marsh and fen vegetation zones in two boreal peatland-pond complexes in northcentral Alberta, Canada. Assuming negligible winter denitrification, we estimated annual denitrification rates of 11 g N·m−2 in marshes and 24 g N·m−2 in fens. Two techniques were employed to measure denitrification: 1) measurements of direct N2-flux were taken from intact cores in gas-tight N-free chambers, and 2) nitrous oxide (N2O) flux was measured in the two fens using in situ chambers. N2 fluxes ranged from 2.14–4.19 mg N·m−2·h−1 in marshes and 6.19–6.81 mg N·m−2·h−1 in fens. N2O release from fen peat ranged from consumption to 0.025 mg N·m−2·h−1. Peat with higher carbon and moisture content was a source of N2O whereas peat with lower carbon and moisture content was a sink. Surface water did not appear to be a major source of nitrate for denitrification. However, denitrification rates were positively correlated with peat extractable nitrate. Combined with mineralization studies, this indicated that soil nitrification provided most of the substrate for denitrification.

Wetlands cover approximately 21% of the land area of the province of Alberta (National Wetlands Working Group 1988) and are unique ecosystems that provide several valuable ecological and economic functions including water storage and flood attenuation, erosion control, water quality improvement and habitat for various plant and animal species (Ducks Unlimited Canada 2004).Many wetlands in Alberta, especially in the southern half of the province, have been negatively impacted by anthropogenic disturbances (Turner et al. 1987) which in turn affect the wetland health and function.The purpose of this report is to conduct a review of the primary literature on Alberta wetlands and identify potential indicators of health of wetland ecosystems in Alberta, specifically in the prairie, aspen parkland and boreal dry mixedwood regions.Despite the large amount of research on various wetlands in North America, information on the general ecology and characteristics of wetlands in Alberta is limited, especially in the aspen parkland and boreal dry mixedwood ecozones of the province.Research on prairie wetlands is also limited within the province, however extensive research has been done in the prairie pothole region of the United States and many of these wetlands are similar to Alberta's prairie wetlands.Information on wetland loss and destruction, extent of disturbance to wetlands and the impacts of these disturbances on wetland health and function, are lacking or minimal within the province of Alberta.While there are some studies of wetland loss in selected areas of the province, there is no complete regional or province-wide mapping or survey of wetlands in Alberta at this time, nor is there a wide-scale assessment of disturbance to wetlands.Compared to other regions of North America very few wetland studies have been conducted in the prairie, parkland and boreal dry mixedwood regions of Alberta and most studies that have been conducted were performed in the last decade (Appendix 1).Without this comprehensive baseline information it is difficult to make inferences about good potential indicators of wetland health in the province, especially given the wide range of natural variation within and among wetlands (US EPA 2002c, d).Based on the scientific literature from studies on Alberta wetlands, as well as other North American wetlands, there does not seem to be any one indicator or class of indicators which will be the most useful to use singly to assess wetland health and function.Potentially useful indicators of wetland health in the prairie region of Alberta include water chemistry parameters such as nutrients (N and P) and turbidity as well as physical characteristics of the riparian buffer areas surrounding wetlands.Potential biological indicators of wetland health in Alberta's prairie region include invertebrate diversity, zooplankton species richness, macrophyte floristic quality and presence of native vs. introduced species, abundance of submersed aquatic vegetation (SAV), presence of monotypic cattail stands and algal biomass and community composition.In the aspen parkland region of Alberta, potentially good indicators of wetland health include water chemistry parameters such as total phosphorus (TP), total dissolved nitrogen A Review of indicators of wetland health and function in Alberta's prairie, aspen parkland and boreal ii dry mixed wood regions A Review of indicators of wetland health and function in Alberta's prairie, aspen parkland and boreal iii dry mixed wood regions TABLE