Benchmarking environmental and economic indicators of sludge management alternatives aimed at enhanced energy efficiency and nutrient recovery.

Wastewater treatment plants (WWTPs) have been developed as multifunctional systems that aim to eliminate pollutants present in wastewater, manage the sludge produced and improve energy efficiency. Specifically, sludge management accounts for the largest share in operational costs. Considering the relevant role of sludge treatment within the overall management scheme, this study aims to evaluate different alternatives and strategies for sludge management and treatment from the perspective of life cycle analysis, with special emphasis on those options that reduce environmental impacts and economic costs. Two pre-treatments (chemical or thermal) and two post-treatments (composting unit followed by land application or incineration) were evaluated to improve the eco-balance of the anaerobic digestion (AD) process in terms of operational (biogas production and digested sludge), environmental and economic indicators. According to the results obtained, both sludge pre-treatment alternatives proved to be an adequate alternative to improve biogas production without negatively affecting environmental and economic impacts. Finally, if the final disposal of the digestate is analysed, its application to the soil as a biofertiliser is recommended, since it presents a better environmental profile than incineration.

Comparative environmental assessment of alternative waste management strategies in developing regions: A case study in Kazakhstan.

The management of municipal solid waste in the Republic of Kazakhstan is still in its infancy. This situation poses a potential threat to the environment and public health and, therefore, it is necessary to introduce improved management schemes in the country. In this study, the life cycle assessment methodology was followed to evaluate the potential environmental benefits of implementing alternative management schemes based on low-waste generation and renewable energy production. The current situation of the capital city Astana was considered as the base case. Environmental results showed that air emissions in terms of landfill gases are the major contributor to climate change impacts, while landfill disposal of the non-recovered fraction of recyclable materials was responsible for the highest impacts in the other categories (especially land use). However, the reuse of recycled materials largely offsets the related environmental burdens, along with energy generation. In comparative terms, it was demonstrated that the proposed waste management scenarios are more environmentally friendly than current practices (S0), mainly owing to the credits associated with the valorisation of renewable energy (S2) and recovered materials (S3). Consequently, the evaluation showed that greater efforts should be made to exploit the energy potential of organic fraction, together with higher recycling rates, to move towards lower environmental impacts associated with municipal solid waste management.

Potentiality of a ceramic membrane reactor for the laccase-catalyzed removal of bisphenol A from secondary effluents.

In this study, the removal of bisphenol A (BPA) by laccase in a continuous enzymatic membrane reactor (EMR) was investigated. The effects of key parameters, namely, type of laccase, pH, and enzyme activity, were initially evaluated. Once optimal conditions were determined, the continuous removal of the pollutant in an EMR was assessed in synthetic and real biologically treated wastewaters. The reactor configuration consisted of a stirred tank reactor coupled to a ceramic membrane, which prevented the sorption of the pollutant and allowed the recovery and recycling of laccase. Nearly complete removal of BPA was attained under both operation regimes with removal yields above 94.5 %. In experiments with real wastewater, the removal of BPA remained high while the presence of colloids and certain ions and the formation of precipitates on the membrane potentially affected enzyme stability and made necessary the periodic addition of laccase. Polymerization and degradation were observed as probable mechanisms of BPA transformation by laccase.

Enzymatic technologies for remediation of hydrophobic organic pollutants in soil.

Worldwide there are numerous contaminated sites as a result of the widespread production and use of chemicals in industrial and military activities as well as poor schemes of waste disposal and accidental spillages. The implementation of strategies for decontamination and restoration of polluted sites has become a priority, being bioremediation with biological agents a promising alternative. Enzyme-based technologies offer several advantages over the use of microbial cells, provided that the biocatalyst meets specific requirements: efficiency to remove the target pollutant/s, non-dependency on expensive coenzymes or cofactors, enzyme stability, and an affordable production system. In this mini-review, the direct application of enzymes for in situ soil bioremediation is explored, and also novel ex situ enzymatic technologies are presented. This new perspective provides a valuable insight into the different enzymatic alternatives for decontamination of soils. Examples of recent applications are reported, including pilot-scale treatments and patented technologies, and the principles of operation and the main requirements associated are described. Furthermore, the main challenges regarding the applicability of enzymatic technologies for remediation of hydrophobic organic pollutants from soil are discussed.

Immobilisation of laccase on Eupergit supports and its application for the removal of endocrine disrupting chemicals in a packed-bed reactor.

Laccase from Myceliophthora thermophila was covalently immobilised on Eupergit C and Eupergit C 250L yielding specific activities of up to 17 and 80 U/g, respectively. Due to its superior activity, Eupergit C 250L was chosen for further research. The somewhat lower catalytic efficiency (based on the ratio between the turnover number and the Michaelis constant, k(cat)/K(M)) of the immobilised enzyme in comparison with that of the free enzyme was balanced by its increased stability and broader operational window related to temperature and pH. The feasibility of the immobilised laccase was tested by using a packed bed reactor (PBR) operating in consecutive cycles for the removal of Acid Green 27 dye as model substrate. High degrees of elimination were achieved (88, 79, 69 and 57% in 4 consecutive cycles), while the levels of adsorption on the support varied from 18 to 6%, proving that dye removal took place mainly due to the action of the enzyme. Finally, a continuous PBR with the solid biocatalyst was applied for the treatment of a solution containing the following endocrine disrupting chemicals: estrone (E1), 17ß-estradiol (E2) and 17α-ethinylestradiol (EE2). At steady-state operation, E1 was degraded by 65% and E2 and EE2 were removed up to 80% and only limited adsorption of these compounds on the support, between 12 and 22%, was detected. In addition, a 79% decrease in estrogenic activity was detected in the effluent of the enzymatic reactor while only 14% was attained by inactivated laccase.

Biotransformation of three pharmaceutical active compounds by the fungus Phanerochaete chrysosporium in a fed batch stirred reactor under air and oxygen supply.

White-rot fungi are a group of microorganisms capable of degrading xenobiotic compounds, such as polycyclic aromatic hydrocarbons or synthetic dyes, by means of the action of extracellular oxidative enzymes secreted during secondary metabolism. In this study, the transformation of three anti-inflammatory drugs: diclofenac, ibuprofen and naproxen were carried out by pellets of Phanerochaete chrysosporium in fed-batch bioreactors operating under continuous air supply or periodic pulsation of oxygen. The performance of the fungal reactors was steady over a 30-day treatment and the effect of oxygen pulses on the pellet morphology was evidenced. Complete elimination of diclofenac was achieved in the aerated and the oxygenated reactors, even with a fast oxidation rate in the presence of oxygen (77% after 2 h), reaching a total removal after 23 h. In the case of ibuprofen, this compound was completely oxidized under air and oxygen supply. Finally, naproxen was oxidized in the range of 77 up to 99% under both aeration conditions. These findings demonstrate that the oxidative capability of this microorganism for the anti-inflammatory drugs is not restricted to an oxygen environment, as generally accepted, since the fungal reactor was able to remove these compounds under aerated and oxygenated conditions. This result is very interesting in terms of developing viable reactors for the oxidation of target compounds as the cost of aeration can be significantly reduced.

Early and midterm results of aortic aneurysm treatment in patients with challenging anatomy using the Aorfix endograft: single-center experience.

UNLABELLED: Since the introduction of the first commercial endofraft to treat the abdominal aortic aneurysm in the early 1990s, there has been a continuous improvement and technology evolution making feasible to treat successfully highly complex AAA with endovascular repair. We have performed EVAR therapy in highly complex aorto-iliac aneurysm using the Aorfix(®) stent-graft system from 2009 to 2011. PATIENTS AND METHODS: A retrospective review to our clinical experience was performed, comparing two groups of patients: 1. Challenging anatomy group treated with Aorfix Endograft. 2. Standard anatomy group was integrated by EVAR procedures performed in patients with aortic angulation less than 75°or non-tortuos iliac vessels. RESULTS: In 96.5-97% of cases a bifurcated endograft was implanted with clinical and technical succes . After 1 year follow up in most cases and at least 6 months follow up in all the series we saw successful results, with aneurysmal sac reduction or stability, 2 type II endoleaks related to lumbar arteries with sac stability and no AAA-related complications were finded in the complex anatomy group. CONCLUSIONS: The 30 days, early-midterm and 12 months results for challenging anatomy group are identical to those finded in standard anatomy and consistent with published data, showing the performance of this endograft system in tortuous anatomies. These early results are quite promising, this particular graft, in its labeled use, is providing an excellent platform to EVAR therapy in challenging anatomies, off label to other devices currently avaliable; however, further studies are needed to evaluate the long-term results.

Hybrid approach to AAA: bilateral "banana" technique to preserve hypogastric artery in complex anatomy aorto-biiliac aneurysm.

UNLABELLED: The surgical approach for hypogastric preservation in aorto-iliac aneurysm (AAA) open repair (OR) has been described and performed with different techniques but all of them represent a higher mortality and potencial complications to the procedure; this is even more critical in bilateral disease. Since the introduction of the first endograft, a continuous development has occurred, such as the stent graft with specific branch designed for preserving antegrade flow in the hypogastric artery. On highly angulated and tortuous iliac anatomies, the use of Sandwich-Graft technique, as described by Armando Lobato, represents a valid alternative to iliac branch. The hybrid approach could be a good treatment option in young patients with AAA affecting hypogastric arteries. PATIENTS AND METHODS: We present the technical description and a case report of bilateral "banana" technique perfor- med with flexible covered stent (Viabahn(®) WL Gore) to preserve both hypogastric arteries combined with open repair in a 52 years old patient. Technical report and Results: A bilateral retrograde endograft was implanted from both external ilac arteries to hypo- gastric artery excluding bilateral common iliac aneurysms followed by an open repair to the AAA (aneurismectomy + aorto bifemoral by-pass) with good inmediate and short-midterm follow up (12 months) CONCLUSIONS: This hybrid technique could be a good approach to hypogastric preservation in low risk and young patients reducing potencial complications of hypogastric artery oclusion.

Reductive dechlorination of α-, ß-, γ-, and δ-hexachlorocyclohexane isomers with hydroxocobalamin, in soil slurry systems.

The present study was carried out to test the viability of a method of reductive dehalogenation of α-, ß-, γ-, and δ-hexachlorocyclohexane (HCH) in soil slurry systems. The soil slurries were maintained under anaerobic conditions, with titanium(III) citrate as a reducing agent and hydroxocobalamin (vitamin B(12a)) as a catalyzing agent. Experiments were carried out with two soil samples with markedly different characteristics (particularly regarding organic matter content), at a small scale and larger reactor scale. HCH concentration was monitored throughout the 24 h duration of the tests. In the low organic matter soil HCH isomers degraded rapidly, in both the small scale and reactor systems, and undetectable levels (<0.5%) were reached within 5 h. However, complete degradation of HCH isomers was not achieved in soil with high organic matter content, and there were differences between the results obtained in the small scale and reactor systems. In the small scale system, the levels of degradation reached 93, 88, 94, and 91%, for α-, ß-, γ-, and δ-HCH, respectively, and the nondegraded HCH was sorbed in the soil. In the reactor system, the reaction stopped after two hours (no more than 65% of any of the isomers was degraded).

Turning waste management into a carbon neutral activity: Practical demonstration in a medium-sized European city.

A Life Cycle Assessment (LCA) with focus on carbon footprint, followed by Life Cycle Costing (LCC) of municipal solid waste (MSW) management were conducted in a residential area of a medium-sized European city of 80,000 inhabitants. The initial results showed high environmental impacts and lack of economic sustainability, due to the high amounts of waste landfilled, the low extent of separate collection, low performance of mechanical-biological treatment as well as absence from alternatives to landfilling of non-recyclable materials. Taking this result as a baseline scenario, three improvement.s were tested with the aim of turning the carbon footprint of the local MSW management system into a neutral value: (i) increased separate collection of recyclables, (ii) enhanced biogas production and (iii) refuse-derived fuel (RDF) production. Successively adding the improvements, three alternative improved scenarios were defined, until reaching a negative carbon footprint, meaning that an optimised system would avoid GHG emissions. The proposed changes were sufficient to achieve carbon neutrality, as well as reduce overall environmental impacts, but were not enough for achieving economic sustainability due to the great influence of collection costs, especially for separate collection. It was concluded that by using an adequate combination of several treatment options and increasing the separate collection of recyclable materials it is possible to turn MSW management into a carbon neutral activity as well as improve its economic balance.

Iron oxide-mediated photo-Fenton catalysis in the inactivation of enteric bacteria present in wastewater effluents at neutral pH.

The pressure on natural water resources associated with increasing water scarcity highlights the value of using reclaimed water through the development of efficient and environmentally friendly treatment technologies. In this work, the use of magnetic nanoparticles in photo-Fenton catalysis for water disinfection was considered to inactivate natural enteric bacteria present in municipal wastewater effluents under white light and neutral pH. The most recommended ranges were evaluated in key variables such as the loading and composition of nanoparticles (NPs), hydrogen peroxide (H2O2) concentration, the light source (UV and visible) and treatment time were evaluated in wastewater disinfection expressed in terms of total coliforms and Escherichia coli colony forming units (CFU). The magnetic separation of NPs allowed the disinfection process to be carried out in different cycles, facilitating the recovery of the nanocatalyst and avoiding its discharge with the treated effluent.

Effect of culture temperature on the heterologous expression of Pleurotus eryngii versatile peroxidase in Aspergillus hosts.

Production of recombinant versatile peroxidase in Aspergillus hosts was optimized through the modification of temperature during bioreactor cultivations. To further this purpose, the cDNA encoding a versatile peroxidase of Pleurotus eryngii was expressed under control of the alcohol dehydrogenase (alcA) promoter of Aspergillus nidulans. A dependence of recombinant peroxidase production on cultivation temperature was found. Lowering the culture temperature from 28 to 19 degrees C enhanced the level of active peroxidase 5.8-fold and reduced the effective proteolytic activity twofold. Thus, a maximum peroxidase activity of 466 U L(-1) was reached. The same optimization scheme was applied to a recombinant Aspergillus niger that bore the alcohol dehydrogenase regulator (alcR), enabling transformation with the peroxidase cDNA under the same alcA promoter. However, with this strain, the peroxidase activity was not improved, while the effective proteolytic activity was increased between 3- and 11-fold compared to that obtained with A. nidulans.

Regionalizing eco-toxicity characterization factors for copper soil emissions considering edaphic information for Northern Spain and Portuguese vineyards.

The management of vineyards depends on the use of plant protection agents. Regardless of the numerous environmental impacts that these pesticides generate during their production, their dosage as pest control agents in vineyards causes an important toxic effect that must be monitored. Copper-based inorganic pesticides are the most widely used agents to control fungal diseases in humid wine-growing regions. It is, however, significant that the environmental analysis of their use through the Life Cycle Assessment (LCA) methodology does not provide detailed information on the potential toxicity of this type of pesticides. Hence, most studies report average values for copper characterization factors (CFs), excluding local soil characteristics. The objective of the study was the spatial characterization of the ecotoxicity factors of copper soil emissions as a function of the chemical characteristics of vineyard soils located in Portugal and Galicia (NW Spain). A multiple linear regression model was applied to calculate the comparative toxic potential. Subsequently, CFs for copper were calculated based on spatial differentiation considering the variable properties of the soil within each wine appellation. The CFs obtained for the area evaluated ranged from 141 to 5937 PAF·m3·day/kgCu emitted, for fibric histosols (HSf) and dystic cambisols (CMd), respectively. Moreover, the average values obtained for Galician and Portuguese soils were 1145 and 2274 PAF·m3·day/kgCu emitted, respectively. The results obtained illustrate the high variability of CF values as a function of the chemical characteristics of each type of soil. For example, Cu soil mobility was linked to organic carbon content and pH. Finally, to validate the representativeness of the calculated CFs, these were applied to the results of 12 literature life cycle inventories of grape production in the area evaluated, revealing that impact scores associated with Cu emissions can considerably vary when spatially-differentiated CFs are implemented.

Enzymatic degradation of low soluble compounds in monophasic water: solvent reactors. Kinetics and modeling of anthracene degradation by MnP.

Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds presenting low water solubility and high hydrophobicity, which greatly hampers their natural biodegradation. The enzymatic degradation of a model compound, anthracene, was evaluated in presence of a miscible solvent for an increased solubility. Manganese peroxidase, a ligninolytic enzyme from white-rot fungi, was used as biocatalyst in a medium containing acetone. The kinetic parameters of the enzymatic degradation of anthracene, obtained from fed-batch experiments, were applied to model the operation of a continuous reactor. Kinetics comprised a Michaelis-Menten equation, modified with an autocatalytic term, assumed to the effect of quinones acting as electron carriers, and a logistic function related to enzyme activity. The continuous reactor has been operated for 108 h, attaining a 90% of anthracene degradation, which demonstrated the feasibility of the system for its application in the removal of poorly soluble compounds. The model of this reactor permitted to predict accurately anthracene degradation in different conditions, such as external addition of anthraquinone and different enzymatic activities.

Environmental and water sustainability of milk production in Northeast Spain.

This study focuses on the assessment of the environmental profile of a milk farm, representative of the dairy sector in Northeast Spain, from a cradle-to-gate perspective. The Life Cycle Assessment (LCA) principles established by ISO standards together with the carbon footprint guidelines proposed by International Dairy Federation (IDF) were followed. The environmental results showed two critical contributing factors: the production of the livestock feed (e.g., alfalfa) and the on-farm emissions from farming activities, with contributions higher than 50% in most impact categories. A comparison with other LCA studies was carried out, which confirmed the consistency of these results with the values reported in the literature for dairy systems from several countries. Additionally, the Water Footprint (WF) values were also estimated according to the Water Footprint Network (WFN) methodology to reveal that feed and fodder production also had a predominant influence on the global WF impacts, with contributions of 99%. Green WF was responsible for remarkable environmental burdens (around 88%) due to the impacts associated with the cultivation stage. Finally, the substitution of alfalfa by other alternative protein sources in animal diets were also proposed and analysed due to its relevance as one of the main contributors of livestock feed.

Operation of a two-phase partitioning bioreactor for the oxidation of anthracene by the enzyme manganese peroxidase.

A study was conducted to determine the potential of a two-phase partitioning bioreactor (TPPB) for the treatment of a poorly soluble compound, anthracene, by the enzyme manganese peroxidase (MnP) from the fungus Bjerkandera sp. BOS55. Silicone oil was used as the immiscible solvent, which contained anthracene at high concentrations. The optimization of the oxidation process was conducted taking into account the factors which may directly affect the MnP catalytic cycle (the concentration of H(2)O(2) and malonic acid) and those that affect the mass transfer of anthracene between the organic and the aqueous phase (solvent and agitation speed). The main objective was carried out in terms of improved efficiency, i.e., maximizing the anthracene oxidized per unit of enzyme used. The TPPB reached nearly complete oxidation of anthracene at a conversion rate of 1.8mgl(-1)h(-1) in 56h, which suggests the application of enzymatic TPPBs for the removal of poorly soluble compounds.

Evaluation of biodiesel as bioremediation agent for the treatment of the shore affected by the heavy oil spill of the Prestige.

The efficiency of different bioremediation products (nutrients, microorganisms and biodiesel) was tested using tiles located in both the supra-littoral and intertidal zones of a beach that was affected by the heavy oil spill of the Prestige. Neither nutrients nor microorganisms meant an improvement with respect to the natural processes. The addition of biodiesel improved the appearance of the treated tiles and apparently accelerated the degradation of the aliphatic and aromatic fractions of the residual fuel oil. Nevertheless, PAHs degradation was similar and very high in all the treatments (80-85% after 60 days). On the other hand, the evolution with time of the amount of vanadium was similar to that of 17alpha(H),21beta(H)-hopane, so it was concluded that vanadium could also be used to estimate the extent of oil degradation in the field. These results also suggested that the residual fuel oil mineralization was very low throughout 1 year in all the treatments. Moreover, the increase of the oxygen content of the residual oil from around 1% till 4-8% indicated that the partial oxidation of hydrocarbons took place, and that the hydrocarbon oxidation products accumulated in the polar fractions. In general, the results pointed out that bioremediation techniques were not suitable for the recovery of shores affected by heavy oil spills.

The prospective use of biochar as adsorption matrix - A review from a lifecycle perspective.

Biochar is obtained from the thermochemical conversion of biomass in an oxygen-limited environment. Beyond its use for soil amendment and carbon sequestration, other value-added applications, such as a green environmental sorbent for different types of pollutants, are also of increasing interest. This paper reviews the available literature on the use of various feedstocks for biochar production as an initial step to compile the required inventory data from material flow data analysis. The environmental evaluation of different schemes of biochar production in a life cycle perspective reports the environmental impacts of the different alternatives, with more sustainable profiles than the use of activated carbon as conventional adsorption material. Moreover, most systems were validated as negative carbon processes with favorable performance regarding climate change mitigation. In particular, materials based on lignocellulosic waste were responsible for the highest environmental benefits, mainly due to their largest energy potential in comparison with other feedstocks.

An anaerobic bioreactor allows the efficient degradation of HCH isomers in soil slurry.

The insecticide gamma-hexachlorocyclohexane (gamma-HCH or lindane), which has been extensively used for agricultural and medical purposes, presents high persistence and toxicity to the environment and low solubility. This study intends to assess the efficiency of an anaerobic reactor to degrade HCH isomers contained in soil slurry cultures. This study was developed in two phases: experiments in flasks to optimize the process parameters, and assessment of the slurry process in the anaerobic slurry reactor operated for an approximate period of a year. The influence of different environmental conditions was evaluated: the HCH concentration (25-100 mg HCH kg-1), the type of substrate (volatile fatty acids or starch), the sludge concentration (2-8 g VSS l-1) and the replacement of spiked soil to simulate a fed-batch operation (10-50%). The best results were obtained when the reactor was operated with a sludge concentration of 8 g VSS l-1, starch concentration of 2 g COD l-1 and soil replacements of 10-20%. Under these conditions, alpha- and gamma-HCH were completely degraded after 10d while nearly 90% beta- and delta-HCH were removed only after 50 d. According to the obtained results related to the total degradation of the HCH isomers and the degradation rates, especially high for alpha- and gamma-HCH, the anaerobic slurry reactor appears to be a good alternative for the degradation of the HCH isomers present in polluted soil.

Fostering the action of versatile peroxidase as a highly efficient biocatalyst for the removal of endocrine disrupting compounds.

Response surface methodology (RSM) was used to optimize the removal of five endocrine disrupting compounds (EDCs) by the enzyme versatile peroxidase (VP): bisphenol A (BPA), triclosan (TCS), estrone (E1), 17ß-estradiol (E2) and 17α-ethinylestradiol (EE2). The optimal variables of enzyme activity (90-100 U L(-1)), sodium malonate (29-43 mM) and MnSO4 (0.8-1 mM) led to very high removal rates of the five pollutants (2.5-5.0 mg L(-1) min(-1)). The structural elucidation of transformation products arising from the enzymatic catalysis of the EDCs was investigated by Gas Chromatography coupled to Mass Spectrometry (GC-MS) and Liquid Chromatography Electrospray Time-of-Flight Mass Spectrometry (LC-ESI-TOF-MS). The presence of dimers and trimers, indicative of oxidative coupling, was demonstrated.