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In 2010 a questionnaire was administered to the renal units of Piedmont and Valle d'Aosta to analyze their procedures for renal biopsy (RB). Seventy-eight percent of units performed RBs, 57% for more than 20 years, but only 43% performed at least 20 BRs per year. 20/21 units performed RB in an inpatient setting and 1/21 in day hospital with the patient remaining under observation the night after. Thirty-two percent did not consider a single kidney as a contraindication to RB, 59% considered it a relative contraindication and 9% considered it an absolute contraindication. In 90.5% of units there was a specific protocol for patient preparation for RB and 86% used a specific informed consent form. Ninety-five percent of units performed ultrasound-guided RB, 60% of them using needle guides attached to the probe. In 81% of units the left side was preferred; 71% put a pillow under the patient's abdomen. All units used disposable, automated or semi-automated needles. Needle size was 16G in 29%, 18G in 58%, and both 16G and 18G in 14% of units; 1 to 3 samples were drawn. One third of units had a microscope available for immediate evaluation of specimen adequacy. After RB, 86% of units kept patients in the prone position for 2-6 hours and all prescribed a period of bed rest (at least 24 hours in 90.5%). 90.5% of units followed a specific postbiopsy observation protocol consisting of blood pressure, heart rate and red blood cell measurements at different times, and urine monitoring and ultrasound control within 12-24 hours (only half of them also employing color Doppler). One third of all units discharged patients after 1 day and two thirds after 2-3 days; all prescribed abstention from effort and from antiplatelet drugs for 7-15 days. In 9 units both RB and tissue processing and examination were done in the same hospital, while 12 units sent the samples elsewhere. 76% obtained results in 2-4 days, 19% in 6-7 days, and 5% in 10-15 days. Less than 20% of the interviewed operators were fully familiar with the clauses of hospital insurance securing their activity. Use of RB is widespread in Piedmont and Valle d'Aosta but its practice shows variation between centers.

The integration of microalgae-bacteria consortia within existing wastewater treatment plants as alternative biological treatment could be an interesting option to improve the sustainability of these facilities. However, the fate of the produced biomass is decisive to make that option economically attractive. The present study aimed to valorize the microalgae grown at a pilot scale and used for the treatment of the centrate from municipal sewage sludge, producing microalgal-based iron nanoparticles (ME-nFe), by hydrothermal carbonization. The final product had high carbon content, strong sorbent power, and reducing properties, due to the presence of zerovalent iron. Different synthesis conditions were tested, comparing iron (III) nitrate nonahydrate (Fe (NO3)3·9H2O) and ammonium iron (III) sulfate dodecahydrate (NH4 Fe (SO4)2·12 H2O) as iron sources, four different Fe/C molar ratios (0.02, 0.05, 0.1, 0.2), and three process temperatures (180, 200, 225 °C). Based on the characterization of all the prototypes, the best one (having a specific area of 110 m2g−1) was chosen and tested for the removal of selected heavy metals by Jar tests. The removal of copper, zinc, cadmium, and nickel from the treated effluent from the wastewater treatment plant was 99.6%, 97.8%, 96.4%, and 80.3%, respectively, also for very low starting concentrations (1 mg L−1). The removal of total chromium, on the contrary, was only 12.4%. Thanks to the magnetic properties, the same batch of ME-nFe was recovered and used effectively for three consecutive Jar tests.

Introduction: Breast cancer (BC) is one of the most common tumors; better screening policies and multidisciplinary approach allow personalized treatment. Radiotherapy (RT) plays a central role in the multimodal approach in BC, and recent evidence has shown the non-inferiority of hypofractionated treatments. The aim of this study was to describe the feasibility and validity of stereotactic RT (SBRT) in BC in a neoadjuvant and exclusive setting. Methods: A PubMed/MEDLINE and Embase systematic review was conducted to assess the role of radiomics in BC. The search strategy was “breast [All Fields] AND “stereotactic” [All Fields] AND “radiotherapy” [All Fields]” and only original articles referred to BC in humans in the English language were considered. Results: A total of 2,149 studies were obtained using the mentioned search strategy on PubMed and Embase. After the complete selection process, a total of 12 papers were considered eligible for the analysis of the results. SBRT in BC was described in 8 studies regarding neoadjuvant approach and 4 papers regarding exclusive approach. Conclusions: Relative low toxicity rates, the reduced treatment volumes in the neoadjuvant setting, and the possibility to replace surgery when not feasible in exclusive setting resulted to be main advantages for SBRT in BC. Current evidence shows that both the neoadjuvant and the definitive settings seem to be promising clinical scenarios for SBRT, especially for EBC.

The use of phototrophic organisms in wastewater treatment is gaining increasing interest, due to the possibility of exploiting photosynthetic oxygenation, thus lowering treatment costs and environmental impacts. Mixed consortia of phototrophic organisms and aerobic bacteria rapidly develop in photobioreactors receiving wastewaters; in this case, the complex mutualistic interactions among microorganisms cannot be easily described, making difficult to forecast removal efficiencies and biomass productivities. Respirometric methods are applied for evaluating bacterial activity in activated sludge (conventional respirometry) or photosynthetic activity in phototrophic organisms (photorespirometry). Photo-respirometric methods can be also exploited for monitoring algae-bacteria systems and for calibrating mathematical models, allowing for a better comprehension of the interactions involved and a more accurate prediction of system efficiencies. A general protocol and a series of guidelines for conducting photorespirometric tests on algal-bacterial suspensions are here proposed, based on the review of experimental protocols applied to evaluate the effects of several parameters on these systems.

The integration of microalgae in the municipal wastewater treatment scheme could certainly be an interesting option to reduce the carbon footprint of the process. The obtained microalgae could be valorized through hydrothermal carbonization (HTC), producing a sorbent material to be used as an alternative to activated carbon. However, HTC of microalgae does produce potentially harmful byproducts. The present work aims to investigate the possibility of using the effluent derived from the hydrothermal carbonization of microalgae (HTC-LF), performed to produce microalgal-based carbon encapsulated iron nanoparticles (ME-nFe), as a growth medium for the microalgae. Since this raw effluent was proved to be toxic for Allivibrio fisheri (EC50 = 1.8 %), the microalgal activity was studied also for detoxification. A 20 % dilution of the HTC-LF, using municipal centrate as the diluent, was proved to be suitable for microalgal growth without affecting the photochemical efficiency. In a continuous test, a community made of Chlorella spp. and Euglena gracilis was able to grow with and without CO2 addition, with average productivity of 62 +/- 5 and 43 +/- 8 mg L-1 d(-1), respectively. The treatment led to a 60 % COD removal, suggesting that the HTC-LF was not harmful to the microalgae-bacteria consortia, which was also able to decrease its toxicity. Environmental implications: The liquid byproduct of the hydrothermal carbonization (HTC-LF) is a known toxic for the water compartment. The possibility to exploit its nutrient content for microalgal growth was already proved by different studies using strong dilution with synthetic medium to perform batch cultivations. Here, the HTC-LF was diluted with the blackwater from biosolid dewatering, without adding any microelements or main nutrients to perform a continuous cultivation. A microalgal community was grown, consuming nutrients and the COD, lowering the toxicity. The obtained biomass was used to produce second-generation nano -particles, designing our process as a cycle in an eco-sustainable way.

Recent literature on the mental health consequences of social distancing measures has found a substantial increase in self-reported sleep disorders, anxiety and depressive symptoms during lockdown periods. We investigate this issue with data on monthly purchases of psychotropic drugs from the universe of Italian pharmacies during the first wave of the COVID-19 pandemic and find that purchases of mental health-related drugs have increased with respect to 2019. However, the excess volumes do not match the massive increase in anxiety and depressive disorders found in survey-based studies. We also study the interplay between mobility, measured with anonymized mobile phone data, and mental health and report no significant effect of mobility restrictions on antidepressants and anxiolytics purchases during 2020. We provide three potential mechanisms that could drive the discrepancy between self-reported mental health surveys and psychotropic drugs prescription registries: (1) stockpiling practices in the early phases of the pandemic; (2) the adoption of compensatory behavior and (3) unexpressed and unmet needs due to both demand- and supply-side shortages in healthcare services.

Melanoma is an extremely aggressive tumor and is considered to be an extremely immunogenic tumor because compared to other cancers it usually presents a well-expressed lymphoid infiltration. The aim of this paper is to perform a multidisciplinary comprehensive review of the evidence available about the combination of radiotherapy and immunotherapy for melanoma. Radiation, in fact, can increase tumor antigens visibility and promote priming of T cells but can also exert immunosuppressive action on tumor microenvironment. Combining radiotherapy with immunotherapy provides an opportunity to increase immunostimulatory potential of radiation. We therefore provide the latest clinical evidence about radiobiological rationale, radiotherapy techniques, timing, and role both in advanced and systemic disease (with a special focus on ocular melanoma and brain, liver, and bone metastases) with a particular attention also in geriatric patients. The combination of immunotherapy and radiotherapy seems to be a safe therapeutic option, supported by a clear biological rationale, even though the available data confirm that radiotherapy is employed more for metastatic than for non-metastatic disease. Such a combination shows promising results in terms of survival outcomes; however, further studies, hopefully prospective, are needed to confirm such evidence.

Phytobenthos is the dominant primary producer in streams and sustains, with the allochthonous organic matter inputs, the higher trophic levels. Among the different groups that constitute the phytobenthos community some, especially diatoms, have been studied deeply while others remain quite overlooked. Hence, a characterisation of the overall phytobenthos community is needed, considering all the main taxonomic groups (diatoms, green algae, cyanobacteria and red algae), as related to the environmental conditions characterizing different alpine streams. Moreover, despite the ecological role played by the phytobenthos the knowledge about the factors that control the variations of the community among streams and throughout the different seasons is still poor. Among the different drivers that regulate the phytobenthos component, a pivotal factor is the occurrence of high-flow events that, controlling the stability of riverbed substrates, influences both the phyto and the zoobenthos composition and distribution. Thus, the frequency and the magnitude of flow disturbances are determinant in regulating the phytobenthos density and the recolonization patterns. The aim of this work was to characterize and compare the phytobenthos communities in different streams highlighting the role of the flow regulation due to hydropower reservoirs accounting for the influence of the lithology and the seasonality. The presented phytobenthos data derive from a one-year sampling campaign in four alpine streams representative of different flow conditions (natural vs regulated flow discharge) and lithology (silicate vs carbonate). The riverbed coverage has been estimated monthly in each stream and the biomass has been quantified. In lab, phytobenthos samples have been analysed to measure the photosynthetic activity and define their composition. The main groups (cyanobacteria, green algae, diatoms and algae with phycoerythrin) have been determined both by phyto-PAM deconvolution and by the quantification of the photosynthetic pigments. In order to estimate the bed disturbance, painted stones of different size classes were located in regular arrays along three transversal transects and the distance travelled was measured during every sampling. The preliminary results indicate that regulated streams seem characterized by a greater algae biomass possibly due to a more stable environment. Concerning the community composition, the percentage of diatoms is significatively higher in silicate substrates. Despite the few hours of light, winter promotes phytobenthos colonisation especially for the low frequency of relevant high-flow events but also for the absence of the shadow due to tree canopy on the riverbed.

Alpine and pre-alpine lotic ecosystems are often remote and not affected by humans, which makes them some of the world’s most pristine ecosystems. However, their status is often altered by the presence of reservoirs that are built to fulfill agricultural needs and hydroelectric demands. These reservoirs also disrupt stream continuity and alter the magnitude, timing, and frequency of natural flows. The present work assessed how high-altitude reservoirs affect the riverine ecosystems focusing on the following: (i) the macroinvertebrate communities, (ii) the breakdown of organic matter, and (iii) the thermal regime. Stretches altered by high-altitude reservoirs had the best conditions for most macroinvertebrate families due to a more stable flow conditions. The breakdown rate of coarse particulate organic matter was not affected by high-altitude reservoirs but its availability was higher in altered compared to pristine stretches. The presence of hydroelectric power plants modified the stream thermal regime. Reservoirs mitigate the atmospheric influence on stream water temperature while run of the river plants strengthen it in the diverted stretches. Where both these alterations were present, the thermal regime of the stream was more similar to the natural ones compared to stretches subjected to only one kind of alteration. This research showed how river impoundment alters the structure of macroinvertebrate communities and the function of the downstream lotic ecosystems and can provide the basis to correctly guide management strategies for lotic ecosystems affected by hydrological alterations.

Tetraselmis suecica was cultivated in a semi-continuously operated tubular photobioreactor fed on aquaculture wastewater (AW) testing two hydraulic retention times (HRT): 10 and 7 days (RUN_1 and RUN_2, respectively). The integrated mechanistic model BIO_ALGAE was validated with experimental data in order to simulate the biomass production and nutrient uptake of T. suecica. Moreover, AW was used as substitute synthetic cultivation medium to test the production of lipids, proteins, and carbohydrates in the microalgal biomass. Preliminary photo-respirometric tests were carried out on the AW suspension containing microalgae and bacteria. Dissolved Inorganic Nitrogen (DIN) and Dissolved Inorganic Phosphorus (DIP) were analyzed for the two RUNs, and no significant difference was highlighted (p > 0.05). On the contrary, the productivity of the Total suspended solids (TSS) was significantly higher (p < 0.05) for RUN_1 (900 mg TSS/L) than for RUN_2 (550 mg TSS/L). The analysis of the biochemical composition of biomass has demonstrated a higher content of proteins than of lipids and carbohydrates for the two RUNs. BIO_ALGAE model was validated by comparing simulated results to experimental data. The model was able to reproduce the pattern of these experimental data quite well, for both nutrient uptake and biomass production. The simulated curve follows the same pattern as the experimental data for both RUNs. The wavelike trend indicates the good accuracy of the simulated curves to reproduce the microalgae growth and nutrient uptake that occurring during daytime and at night. With this study, BIO_ALGAE Model was demonstrated to be useful to simulate bioremediation and microalgae production in aquaculture wastewater in a semi-continuous system with different environmental factors. The photo-respirometric outputs were compared with the process rates affecting dissolved oxygen dynamics computed by the mathematical model. The authors would like to thank the Italian Ministry of University and Research (MIUR) and Fondazione Cariplo, for funding part of this research (“Vademecum” and “Il polo delle microalghe” projects) and Dr. Nadia Margariti for her valuable help in laboratory.

Milk whey processing wastewaters (MWPWs) are characterized by high COD and organic nitrogen content, the concentrations of phosphorus are also relevant. A microalgal-based process was tested at lab scale in order to assess the feasibility of treating MWPW without any dilution or pre-treatment. Different microalgal strains and populations were tested. Based on the obtained results, Scenedesmus acuminatus (SA) and a mixed population (PM) chiefly made of Chlorella, Scenedesmus, and Chlamydomonas spp. were grown in duplicate for 70 days in Plexiglas column photobioreactors (PBRs), fed continuously (2.5 L culture volume, 7 days hydraulic retention time). Nutrient removal, microalgae growth, photosynthetic efficiency, and the composition of microalgal populations in the columns were monitored. At steady state, the microalgal growth was similar for SA and PM. The average removal efficiencies for the main pollutants were: 93% (SA), 94% (PM) for COD, 88% (SA) and 90% (PM) for total N, and 69% (SA) and 73% (PM) for total P. The residual pollution levels in the effluent from the PBRs were low enough to allow their discharge into surface waters, such good results were achieved thanks to the synergy between the microalgae and bacteria in the CO2 and oxygen production/consumption and in the nitrogen mineralization.

The role of P content on the treatment and valorization of the liquid fraction of digestate, namely centrate, through microalgae-based technologies was evaluated in this study. The performance of four column photobioreactors, which were fed on diluted centrate with corrected (10 mg N/ mg P) and not modified (129 mg N/ mg P) N:P ratio, were monitored and compared. The results demonstrated that P shortage in the centrate affected neither the total nitrogen and COD removal rate nor the volumetric biomass productivity, suggesting that expensive addition of P salts is not necessary to maximize the efficiency of the process. On the contrary, the addition of P to the centrate promoted the ammonia oxidation process as higher nitrite production was observed in the photobioreactors with adjusted N:P ratio than in the ones fed with the non-adjusted N:P ratio. These findings were confirmed by fluorescence in-situ hybridization and quantitative PCR assays, which revealed a higher number of ammonia-oxidizing bacteria in the microalgal suspensions cultivated on centrate with P addition. In conclusion, the N:P ratio in the centrate seems to have a role in controlling the nitrification process rather than in the overall nutrient removal rate and biomass productivity of the microalgae-based system.

The definition of relationships among the attributes of macroinvertebrate communities and environmental gradients is fundamental to understand ecological dynamics. Testing the response of macroinvertebrate communities and the related metrics to the action of multiple drivers is crucial to provide reliable tools for the management and conservation of freshwater ecosystems. In this study habitat conditions, seasons and physical–chemical water characteristics were evaluated as potential limiting factors for macroinvertebrate communities. 42 sites, along 11 pre-Alpine rivers and streams, were surveyed for macroinvertebrate communities and water chemistry, collecting a total of 387 samples. Hydromorphological characteristics and habitat availability in each sampling site were assessed to describe different features of channel, banks and vegetation that can be relevant for management purposes. Macroinvertebrate community characteristics were summarized by both structural metrics (i.e. density, diversity and taxonomy-based) and ecosystem attributes derived from functional trait analysis. Functional traits are based on morphological and behavioural attributes associated with feeding, modes of attachment, concealment and locomotion, together with voltinism and drift propensity. In this framework, quantitative models have been developed to predict the potential characteristics of macroinvertebrate communities as a function of selected environmental variables. These relationships can be used to predict the effects of river restoration programs on macroinvertebrate diversity and ecosystem processes. The various metrics considered in this study may help to raise a better awareness in the natural functioning of river ecosystems, the selection of effective strategies for the conservation of biological communities, and the evaluation of river restoration success, thus supporting decision-making processes.

This study aims at demonstrating the feasibility of using microalgae-bacteria consortia for the treatment of the sidestream flow of the supernatant from blackwater dewatering (centrate) in an urban wastewater treatment plant in Northern Italy. A 1200 L raceway reactor was used for the outdoor cultivation of a diverse community of Chlorella spp., Scenedesmus spp. and Chlamydomonas spp. in continuous operation mode with 10 days hydraulic retention time. During the trial, an average daily areal productivity of 5.5 ± 7.4 g TSS m−2 day−1 was achieved while average nutrient removal efficiencies were 86% ± 7% and 71% ± 10% for NH4-N and PO4-P, respectively. The microalgal nitrogen assimilation accounted for 10% of the nitrogen in the centrate while 34% was oxidized to nitrite and nitrate. The oxygen produced by microalgae fully covert the oxygen demand for nitrification. This suggests that the proposed process would reduce the aeration demand for nitrification in the water line of the plant, while producing algal biomass to be further valorized for energy or material recovery.

Respirometric techniques are useful tools to evaluate bacterial activities in activated sludge processes due to their fast execution and the possibility to obtain several kinetic parameters from a single test. Using such techniques in microalgae-bacteria consortia treating wastewater could allow a better understanding of mutual interactions between the microbial populations as a function of environmental parameters. This work aims at developing and testing a novel experimental respirometric protocol to determine oxygen uptake rates and oxygen production rates by a microalgae-bacteria consortium. The defined protocol is characterized by alternating light/dark regimes and by dosing substrates/inhibitors to selectively activate/inactivate microalgal and bacterial metabolisms. The protocol was then applied on microalgal and bacterial consortia, which were grown on the liquid fraction of black water from biogas plants fed on agricultural and municipal waste sludge. Results elucidate the presence and activity of microalgae and nitrifying bacteria in the tested systems, suggesting that the respirometric tests could be included into monitoring procedures of photobioreactors/algal ponds.

The presence of antibiotic resistant bacteria (ARB) in wastewater was investigated and the role of wastewater treatment plants (WWTPs) in promoting or limiting antibiotic resistance was assessed. Escherichia coli (E. coli) and total heterotrophic bacteria (THB) resistance to ampicillin, chloramphenicol and tetracycline was monitored in three WWTPs located in Milan urban area (Italy), differing among them for the operating parameters of biological process, for the disinfection processes (based on sodium hypochlorite, UV radiation, peracetic acid) and for the discharge limits to be met. Wastewater was collected from three sampling points along the treatment sequence (WWTP influent, effluent from sand filtration, WWTP effluent). Antibiotic resistance to ampicillin was observed both for E. coli and for THB. Ampicillin resistant bacteria in the WWTP influents were 20–47% of E. coli and 16–25% of THB counts. A limited resistance to chloramphenicol was observed only for E. coli, while neither for E. coli nor for THB tetracycline resistance was observed. The biological treatment and sand filtration led to a decrease in the maximum percentage of ampicillin-resistant bacteria (20–29% for E. coli, 11–21% for THB). However, the conventionally adopted parameters did not seem adequate to support an interpretation of WWTP role in ARB spread. Peracetic acid was effective in selectively acting on antibiotic resistant THB, unlike UV radiation and sodium hypochlorite. The low counts of E. coli in WWTP final effluents in case of agricultural reuse did not allow to compare the effect of the different disinfection processes on antibiotic resistance.

BACKGROUND: Secondary effluent wastewaters still contain resources including water and nutrients that must be safely reused and recovered. In this study, the combined role of microalgae as disinfectant and nutrient removal agent was evaluated for the potential application of a microalgae-based process as a cost-effective tertiary treatment. Nutrient removal, biomass productivity and disinfection performances were monitored in laboratory-scale photobioreactors (batch and continuous) fed on a secondary effluent mixed with a 10% on influent collected at a large municipal wastewater treatment plant where tertiary disinfection is performed by UV treatment. RESULTS: In microalgae-based batch disinfection tests, Escherichia coli counts (0.5 ± 0.7 log CFU 100 mL−1) were comparable to those after traditional UV process (0.7 ± 0.84 log CFU 100 mL−1) and lower than in tests where light was applied without microalgae. In the following continuous test, E. coli counts were reduced by one order of magnitude and the pathogenic strain of E. coli O157:H7/H−, Salmonella spp. and indicators such as Bacteroides spp. and Enterococcus spp. were never detectable in the effluents by molecular tools. Total nitrogen and phosphorus removals reached 93 and 100%, respectively, while the algal biomass productivity of the system averaged 50 ± 30 mg TSS L−1 day−1. CONCLUSIONS: The effluents of the photobioreactors reached quality standards appropriate for water reuse. Moreover, nutrients could be recovered through the generation of algal biomass suitable for further valorization. © 2019 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

BACKGROUND: Microalgae–bacteria‐based processes are among the most promising low‐cost technologies to treat livestock wastewaters. The current literature reports the need for pretreatment or dilution of piggery wastewater for adequate microalgal growth. The aim of this study is to optimize the potential of microalgal–bacterial communities to treat undiluted and untreated piggery wastewater by investigating the influence of some operational parameters such as phosphorus and CO₂ availability and hydraulic retention time on the nitrogen removal efficiency and biomass productivity. RESULTS: The microalgal community (dominated by Chlorella spp.) developed quickly and remained quite stable. The rates of biomass production and NH₄‐N removal were 55 ± 30 mg TSS L⁻¹ day⁻¹ and 13 ± 3 mg NH₄‐N L⁻¹ day⁻¹ respectively. CO₂ adjustment had a positive effect on microalgal growth and NH₄‐N removal. CONCLUSION: Data confirm the ability of the microalgal–bacterial consortium to grow on undiluted and untreated piggery wastewater under semi‐continuous conditions. Synergy between algae and bacteria seems positive since photosynthesis produces the oxygen needed for ammonia oxidation. © 2019 Society of Chemical Industry

This study was carried out to assess the efficiency of a pilot-scale bubble-column reactor to remove nitrogen in centrate from the biosolid dewatering of a municipal wastewater treatment plant whilst producing biomass for agricultural purposes. The column was inoculated with a mixed community of Scenedesmus and Chlorella spp. and operated outdoor in batch for 55 days and in continuous for further 130 days. In continuous, the average daily biomass productivity was 40 ± 62 mg TSS L −1 d−1 and the average NH4+-N removal was 20 ± 10 mg L −1 d−1. Nitrification was fostered by photo‑oxygenation leading to the oxidation of 34 ± 27% of the incoming ammonia nitrogen. Microalgal and bacterial activity inside the column was analyzed by the Generalized Linear Models in order to understand the main factors affecting the process performances. Microalgal growth was affected positively by the NH4+-N content in the influent and negatively by the amount of TSS entering the system, probably due to the competition between microalgae and bacteria for phosphorus and other nutrients. The removal rate of NH4+-N was positively affected by NH4+-Nin (influent concentration) and by pH, whose increase fosters stripping, and decreased for increasing NH3-N concentrations, responsible for inhibiting nitrifying bacteria. NH4+-N oxidation was the result of complex interactions between algae and bacteria and was also affected by flow and solar radiation. No other specific limiting factors have been highlighted. The possibility of improving the process performance by controlling pH, by supplying off-gas as CO2 additional source, appears as an interesting option. In view of a scale-up, the most relevant expected result would be the energy saving due to the decrease in the oxygen demand for nitrification in the water line. The microalgal biomass grown on centrate was suitable for agricultural use due to its low contamination by heavy metals.

The final publication is available at Springer via http://dx.doi.org/10.1007/s11270-019-4122-0 This study investigates and compares the uptake of nutrients (nitrogen, phosphorus) and the growth of Tetraselmis suecica and Dunaliella tertiolecta in aquaculture wastewater. The obtained data were used to implement and calibrate the microalgae-bacteria model BIO_ALGAE to simulate the bioremediation and the biomass production of these species. The microalgae were cultivated in batch conditions for 7 days using 120-L vertical column photobioreactors. In the first 4 days, after which the algal density reached a steady state, the average biomass production was 83.7 ± 4.4 mg/L/day for T. suecica and 56.4 ± 5.1 mg/L/day for D. tertiolecta. The two species were able to remove more than 96% of dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP). The total lipid content was analyzed at the end of the 7 days; T. suecica and D. tertiolecta had different lipid content: 75.8 ± 1.6% and 23.2 ± 2.0%, respectively. The BIO_ALGAE model fits very well the experimental data of both species in terms of biomass and nutrient uptake and could be an effective tool to predict the production of microalgae using aquaculture wastewater as growth media, obtaining at the same time the removal of nutrients from wastewater and the production of biomass to be used as feed. In particular, this mathematical model can be applied to forecast the performance under different operating conditions, for the design, optimization, and control of the process in aquaculture systems.

The thermal regime of Alpine streams: natural controls and effect of hydroelectric power production Riccardo Fornaroli, Luca Bonacina, Francesca Marazzi, and Valeria Mezzanotte University of Milano-Bicocca, Department of Earth and Environmental Sciences, Milan, Italy (riccardofornaroli@gmail.com) Since the earliest studies water temperature was recognized as one of the most important drivers in stream ecosystems, shaping both biodiversity and ecosystem functioning. So, it was often included as a factor in stream classification systems. The temperature is critical to aquatic organisms through its effects on metabolic rates and thus on growth. Moreover, water temperature relates to the outbreaks of disease, to the toxicity of numerous substances, to the ability of fish to migrate and to many other ecosystem attributes. Despite the recognized biological importance of water temperature, stream thermal regime alterations were rarely quantified in bioassessment programs and few quantitative information about the natural thermic conditions of Alpine streams are available. Besides, the ecological consequences of differences in the thermal regimes were highlighted to be important for many species of fish and invertebrates, but few studies focus on their consequences at community or ecosystem level which are the subject of bioassessment. In the present study we monitored water temperature of streams belonging to the Alpine catchment of Serio River (Italy), in reaches selected as representative of different natural conditions and human alterations. The collected data, with air temperature, flow estimates and diversion rates of hydroelectric power plants, were used to produce quantitative models able to predict the temperature of stream water. Those models describe the effects of meteorological conditions on thermal regime for snow-melt/storm-water and groundwater fed streams. This is the basis for the evaluation of natural thermal regime, allowing to reconstruct temperature time series when only spot measurements are available. The developed models can also be used to evaluate the thermal alterations due to the presence and management of high altitude reservoirs and run-of-river hydroelectric power plants on snow-melt/storm-water fed streams. High altitude reservoirs profoundly alter the thermal regime of streams both on daily and seasonally basis with potential implications for the overall ecosystem dynamics. Structural measures (e.g. multiple level outlets) can reduce the alteration to the downstream sectors while management action (e.g. residual flow) play only a minor role. On the other hand, the overall impact (from upstream the diversion to downstream the release) of run-of-river hydroelectric power plants on thermal regime is almost negligible. The key drivers of thermal alterations in the diverted stretches were the distance from the diversion and the residual flow. The produced models, despite their simplicity, can be the basis to predict or describe the thermal alterations caused by hydroelectric power production in Alpine streams. Further research is needed to properly describe the relationships among selected characteristics of thermal regime and biological communities. Similarly to what was done in the last 10 years for the development of flow-ecology relationships, emphasis must be placed to the effects of thermal regime on the ecological parameters used for bioassessment. This kind of information will allow to predict or to describe changes within the biological communities and in ecosystem functions and ultimately to properly manage and conserve the Alpine stream ecosystems.

Dreissena polymorpha is a widespread filter-feeder species, resistant to a broad range of environmental conditions and different types of pollutants,which has recently colonized Italian freshwaters. Although widely used to monitor pollution in freshwater environments, this species is also an important food source for some fish and water birds. It can also be used to concentrate or remove particulate organic matter to interrupt avian-to-human transmission of pollutants and control health risks for animals and humans. In this study, the accumulation/inactivation in D. polymorpha of human health-related spiked enteric viruses was described. The removal of endogenous Escherichia coli, the classical indicator of fecal contamination,was tested as well.Our preliminary lab-scale results demonstrate that zebra mussels can reduce significantly poliovirus titer after 24 h and rotavirus titer after 8 h. E. coli counts were also reduced in the presence of zebra mussels by about 1.5 log after 4 h and nearly completely after 24 h. The fate of the two enteric viruses after concentration by zebra mussels was also investigated after mechanical disruption of the tissues. To our knowledge, the accumulation from water and inactivation of human health-related enteric viruses by zebra mussels has never been reported.

Integration of archaeoseismic observations, geological and geophysical surveys and a critical review of historical written sources contributed to shed light on the effects of the 847 CE earthquake that struck a large area of southern-central Italy. New archaeoseismic evidence of a strong earthquake which occurred around the middle of the ninth century CE comes from two Medieval archaeological sites along the Volturno Valley, between Campania and Molise regions. Historical documentation and its evidence include the tilting of pillars in the Basilica of Santa Maria near Alvignano (northern Campania region) and a collapsed masonry wall in the Abbey of San Vincenzo al Volturno near Isernia (northern Molise region). At Alvignano, a site so far unrecorded in seismic catalogues for the 847 earthquake, geoelectrical and georadar investigations were used to explore the subsoil and study local site conditions, which could have influenced co-seismic ground motion. Interpretation of geophysical surveys calibrated by stratigraphy of available boreholes document the presence of altered pyroclastic deposits, which likely enhanced site effects at Alvignano. Analysis of damage historical descriptions and of archaeological reports indicates that the 847 seismic event damaged a wide area between Latium, Campania and Molise, with destruction of the town of Isernia and damages in Rome. Because the damaged area for this medieval earthquake is loosely defined in literature, the present study represents a contribution to better define the shaking area and provide new hints on the extent and location of the possible seismogenic source.

This paper addresses the efficiency of a microalgae-based agricultural digestate treatment at pilot-scale in an outdoor raceway pond (880 L, pH-dependent CO2 dosage) and in a bubble column (74.5 L, air-bubbling). Specifically, nitrogen removal, evolution of the algae-bacteria consortium, and the actual process applicability in the Po Valley climate are discussed. The performance of the two reactors varied seasonally. The average algal productivity in the raceway was 32.4 ± 33.1 mg TSS·L−1·d−1 (8.2 ± 8.5 g TSS·m−2·d−1) while in the PBR it was 25.6 ± 26.8 mg TSS·L−1·d−1; the average nitrogen removal was 20 ± 29% (maximum 78%) and 22 ± 29% (maximum 71%) in the raceway and in the column, respectively. Nevertheless, nitrification had a key role as 61 ± 24% and 52 ± 32% of the nitrogen load was oxidized in the raceway and in the column, respectively.

This work concerns the possibility of using phycoremediation of piggery wastewater (PW) in order to remove nitrogen and to send the produced algal biomass to anaerobic digestion. A semi-continuous culturing test was performed in 150 mL glass test tubes (4.5 cm diameter, 20 cm high), in four replicates, and run for 90 days. Light was provided artificially, with 12 h dark/light periods, mixing was allowed by air bubbling and temperaturewas 20±2°C. Algae developed quickly with values over 1 g TSS L-1 after one week and maximumconcentrations between 2.4 and 2.7 g TSS L-1, and the community was made by Chlorella and Scenedesmus spp., in similar proportion all over the test. The average productivity was 0.26 to 0.40 g L-1 day-1. In the absence of pH control, the intense photosynthesis raised pH, whose value was proportional to the TSSconcentration. The pH raise caused the production and stripping of NH3-N (26% of the inflow N), while the algal assimilation of N accounted for 45% and the oxidation for 25%. The overall % removal was about 96% for NH4-N, 85% for P and 74% for COD. The maximum methane production was 267 NmL CH4 g VS-1 (mean of the two replicates), higher than reported for pig and cow manure.

A constructed wetland system composed of a subsurface flow wetland, a surface flow wetland and a facultative pond was studied from July 2008 until May 2012. It was created to treat the domestic sewage produced by a hamlet of 150 inhabitants. Monthly physicochemical and microbiological analyses were carried out in order to evaluate the removal efficiency of each stage of the process and of the total treatment system. Pair-wise Student's t-tests showed that the mean removal of each considered parameter was significantly different (α = 0.05) between the various treatment phases. Two-way ANOVA and Tukey's HSD tests were used to find significant differences between wetland types and seasons in the removal efficiency of the considered water quality parameters. Significant differences in percent removal efficiency between the treatment phases were observed for total phosphorus, total nitrogen, ammonia nitrogen and organic load (expressed as Chemical Oxygen Demand). In general, the wastewater treatment was carried by the sub-superficial flow phase mainly, both in growing season and in quiescence season. Escherichia coli removal ranged from 98% in quiescence season to >99% in growing season (approximately 2–3 orders of magnitude). The inactivation of fecal bacteria was not influenced by the season, but only by the treatment phase.

The metallic element pollution is a serious environmental problem but still unsolved since these contaminants are released mainly by human activity, reaching all the environmental compartments. Traditional wastewater treatment plants are very efficient in removing metallic elements only when their concentration is in the order of mg/L, but are not able to remove them until μg/L, as it would be needed to cope with the water quality standards in low flow receptors. Therefore, the aim of our study was to evaluate the potential removal of some recalcitrant metallic elements to the classical treatments, by the natural process of bio-filtration performed by the invasive zebra mussel (Dreissena polymorpha). For this purpose we built a pilot-plant at the Milano-Nosedo wastewater treatment plant, where we placed about 40,000 D. polymorpha specimens appointed to the wastewater bio-filtration. The metallic element removal due to zebra mussel activity was evaluated in the treated wastewater with a plasma optical emission spectrometry (ICP-OES). Data obtained in these experiments showed an encouraging metallic element removal due to D. polymorpha activity; in particular, the total abatement (100%) of Cr after one day of bio-filtration exposure is remarkable. Therefore, this study encourages further research related with the use of bivalves as a new tool for the wastewater depuration process; in this regard, the contaminated mollusks used in the bio-filtration could be incinerated or stored in special landfills, as is also the case of traditional sewage sludge.

Questa tesi è volta a valutare l’integrazione delle microalghe in impianti di depurazione con il duplice scopo di rimuovere azoto e produrre biomassa da convogliare ai digestori anaerobici. In particolare, questa tesi si concentra sulla identificazione dei acque reflue di tipo agricolo e civile (come effluenti, centrati, digestato, e una miscele di loro) più idonee ad essere usate come substrato per la cultura microalghe. Il capitolo 2 contiene un resoconto che tratta degli attuali approcci per la produzione di biomassa microalgale utilizzando diversi tipi di rifiuti. Il cuore della mia sperimentazione è descritta nei capitoli 3-7; in particolare, il capitolo 3 mostra i risultati di test nei quali il centrato di origine civile è stato usato come substrato per la produzione di biomassa algale. La novità dello studio consiste: (i) nell’uso di centrato tal quale come substrato di crescita, mentre la maggior parte dei dati di letteratura sono stati ottenuti su refluo pretrattato, (ii) nell'uso di un fotobioreattore alimentato in continuo e (iii) nello svolgimento delle prove in condizioni ambientali naturali. Questo lavoro ha dimostrato che le microalghe (Chlorella sp e Scenedesmus sp) sono in grado di crescere facilmente sul centrato e il loro tasso medio di crescita specifico, che varia tra 0,14-0,16 d-1 è comparabile con i dati di letteratura. Anche i test di produzione di biometano (BMP) hanno mostrato buoni risultati: il BMP ottenuto dalla biomassa microalgale è più lento rispetto ai fanghi, ma il suo valore finale è leggermente superiore (208 mLCH4 gVS-1 vs 190 mLCH4 gVS-1). Nel capitolo 4 sono stati studiati diversi reflui agricoli, che potenzialmente potrebbero essere usati come substrato di crescita per le microalghe. Le analisi chimiche e fisiche hanno dimostrato che le frazioni liquide di letame suino potrebbe essere utilizzato a tale scopo. Nel capitolo 5 viene proposto un pre-trattamento con carboni attivi (AC) del centrato di origine suina per facilitare la crescita microalghe. Sono stati testati diversi dosaggi di carbone attivo e il dosaggio di 40 g L-1 e 10 minuti di tempo di adsorbimento sembra essere il più promettente. Nello specifico la riduzione della torbidità del refluo è stata pari all’88%. Gli incoraggianti risultati in scala di laboratorio presentati nel Capitolo 4 e 5 giustificano le successive sperimentazioni su scala pilota, utilizzando reflui di origine agricola come fonte di nutrienti per microalghe. Nel capitolo 6 viene presentato il lavoro in scala pilota, un fotobioreattore è stato installato presso una azienda agricola nel Nord Italia. Durante la sperimentazione, la densità microalghe è rimasta abbastanza costante, intorno al valore medio di 0,55 gTS/l, mentre le efficienze di rimozione dell’azoto totale e di N-NH4+ erano entrambe molto alte (in media 80 e 87%, rispettivamente). L'obiettivo principale del capitolo 7 è volto a trovare la migliore tecnica di separazione della biomassa algale dal substrato di crescita. In questa sezione sono stati testati tre processi di separazione liquido/solido della biomassa microalgale: (i) sedimentazione per gravità; (ii) centrifugazione, (iii) flocculazione. Le principali conclusioni sono riportate nel capitolo 8: l'integrazione delle microalghe negli schemi di trattamento delle acque reflue offre una strategia economicamente fattibile e ambientalmente sostenibile; la crescita microalgale è fortemente influenzata dalle condizioni ambientali; il pretrattamento del digestato, combinato con i processi di strippaggio e adsorbimento con carbone attivo potrebbe migliorare notevolmente l'efficacia della coltivazione delle microalghe; le microalghe potrebbero essere co-digerite con fanghi di scarto senza effetti negativi sul consorzio anaerobico, nonostante le biomassa microalgale abbia alcuni punti critici come la parete cellulare resistente che limita la sua bioconversione. This thesis deals with the feasibility of including a mixed microalgal community in a real wastewater treatment sequence with the double aim of removing nitrogen and producing biomass to feed the anaerobic digesters. In particular, this thesis focuses on identification of relevant waste streams from agricultural and municipal activities (like effluents, centrates, digestates, and a mixture of them) as a substrate for microalgal culture. Chapter 2 contains a critical review, this manuscript summarizes the current approaches to microalgal biomass production using waste streams, including wastewater, waste or CO2-enriched gas (flue gas and biogas), waste organics (i.e., crude glycerol) and waste heat, as well as the primary common operational challenges and corresponding mitigation strategies involved in culturing approaches. The core of experimentation is described in Chapters 3-7 using wastewater from urban or agriculture activity as a substrate for microalgal culture. In particular, Chapter 3 shows the results of experimentation using municipal centrate to produce biomass to feed the anaerobic digesters removing at the same ammonia nitrogen. The novelty of the study consists in the use of raw centrate from urban wastewater treatment plant as a substrate to grow microalgae, while the majority of literature data were obtained on pre-treated (diluted and/or supplemented and/or furtherly clarified) centrate samples, in the use of a continuously fed PhotoBio Reactor (PBR) operated under natural, uncorrected environmental conditions. This work demonstrates that microalgae (Chlorella sp and Scenedesmus sp) are able to easily grow on the centrate. The average specific growth rate in indoor and outdoor batch tests is satisfactory and comparable with literature data, ranging between 0.14-0.16 d-1. During the continuous test the average biomass production is 50 mgTSS L-1 d-1 and the difference between N-NH4 concentration in the influent and in the effluent demonstrates an important removal. Also BMP tests showed good results: the production of biomethane from algal biomass is slower than from sludge, but its final value is slightly higher than that from waste sludge (208 mLCH4 gVS-1 vs. 190 mLCH4 gVS-1). Wastewaters from agricultural activities are the subject of Chapter 4, chemical and physical analyses showed that the liquid fractions of swine manure and the first effluent could be suitable for algal treatment, while the other samples had unacceptable levels of both solid content and turbidity which would seriously limit light penetration. The papers in Chapter 4 and Chapter 5 report the results obtained in lab-scale tests using the agro wastes which had been shown to be more suitable. In Chapter 5 a new approach is proposed using Activated Carbon (AC) from wood as a pre-treatment to facilitate microalgal growth, without addition of tap water for dilution. The optimal optical density values were obtained with 40 g L-1 of AC dosage and 10 minutes adsorption time, corresponding to 88% of turbidity reduction. Then semi-continuous microalgae culturing were tested using adsorbed and not adsorbed liquid centrate (3 replicates). The encouraging lab scale results presented in Chapter 4 and Chapter 5 justify further pilot-scale experimentation, using agrowastes as the nutrient source for microalgae, presented in Chapter 6. The pilot scale (PBR) was installed at a piggery farm in Northern Italy. During the culturing period, microalgal density remained quite constant, around the average value of 0.55 gTSS/L, and the efficiency of Total Nitrogen and of N-NH4+ removal were both very high (on average 80 and 87%, respectively). The search for the best biomass harvesting technique is the main objective of Chapter 7. In this point, microalgal biomass is processed by three solid/liquid separation processes: gravity settling; centrifugation tests, flocculation tests. The main conclusions are reported in Chapter 8.

This paper discusses the possibility of including the culturing of microalgae within a conventional wastewater treatment sequence by growing them on the blackwater (BW) from biosolid dewatering to produce biomass to feed the anaerobic digester. Two photobioreactors were used: a 12 L plexiglas column for indoor, lab-scale tests and a 85 L plexiglas column for outdoor culturing. Microalgae (Chlorella sp. and Scenedesmus sp.) could easily grow on the tested blackwater. The average specific growth rate in indoor and outdoor batch tests was satisfactory, ranging between 0.14 and 0.16 day−1. During a continuous test performed under outdoor conditions from May to November, in which the off-gas from the combined heat and power unit was used as the CO2 source, an average biomass production of 50 mgTSS L−1 day−1 was obtained. However, statistical analyses confirmed that microalgal growth was affected by environmental conditions (temperature and season) and that it was negatively correlated with the occurrence of nitrification. Finally, the biochemical methane potential of the algal biomass was slightly higher than that from waste sludge (208 mLCH4 gVS−1 vs. 190 mLCH4 gVS−1).

The liquid fraction of digestate produced by agricultural biogas plants is rich in macro and micronutrients that are valuable for the culturing of microalgae. Nonetheless, the high ammonium concentration may cause toxicity and the high optical density may reduce light penetration, negatively affecting the biomass production rate. Dilution with fresh water has been frequently suggested as a mean for improving the digestate characteristics in view of microalgal culturing. In this paper, the feasibility of culturing microalgae on undiluted raw digestate or on digestate after pretreatment by stripping and adsorption was investigated. First, adsorption tests were performed using commercial activated carbon from wood in order to identify appropriate conditions for optical density (OD) reduction. Up to 88% reduction was obtained by dosing 40gL−1 after 24h of contact time. Then, culturing tests were performed on a microalgal inoculum including mainly Chlorella spp. and Scenedesmus spp. under controlled temperature and light conditions during 6–14weeks. Raw, stripped, and stripped and adsorbed digestate samples were tested. The biomass production rate increased from 27±13mgTSSL−1d−1 on raw digestate, to 82±18mgTSSL−1d−1 by using stripped digestate, and to 220±78mgTSSL−1d−1 by using the stripped and adsorbed digestate. Moreover, nitrification was constantly suppressed when using the stripped and adsorbed digestate, while relevant nitrite built-up was observed when using raw and stripped digestate. These results suggest that microalgae are able to grow on the raw digestate, provided that long hydraulic retention times are applied. A much faster growth (up to 10 times) can be obtained by pretreating the liquid fraction of digestate by stripping and adsorption, which may be an effective means of improving the areal productivity of microalgal culturing on digestates.

Global increases in the generation of waste streams, including liquid, gaseous, and solid waste, have been posing serious challenges for waste management as a result of their potential impacts on receiving environments and climate change. The conversion of waste streams into useful bioenergy, biofuels, and bioproducts through recycling and/or recovery has been presented as a promising alternative. Coupling the bioremediation of waste streams with microalgae-based biofuel production, offers an alternative strategy to achieve waste-to-biofuel and bioenergy. A group of unicellular photosynthetic eukaryotes, microalgae require relatively simple nutrients and inorganic carbon sources to support their growth, while accumulating several biofuel precursors, such as starch or storage lipids. This review summarizes the current approaches to microalgal biomass production using waste streams, including waste-water; waste or CO2-enriched gas (flue gas and biogas); waste organics (i.e., crude glycerol); and waste heat, as well as the primary common operational challenges and corresponding mitigation strategies involved in cultivation approaches. Moreover, microalgal metabolic pathways supporting the biosynthesis of energy-rich molecules such as triacylglycerides (TAG) and starch are discussed. Metabolic constraints and potential approaches for the enhancement of microalgal TAG accumulation are systematically and critically analyzed. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd.

a b s t r a c t This study shows the evaluation of the possible use of the freshwater bivalve Dreissena polymorpha for the removal of some recalcitrant contaminants, namely many pharmaceuticals and drugs of abuse that are not sufficiently removed from civil wastewaters. This mollusk has an enormous filtering capability and is highly resistant to natural and anthropogenic stresses and to a significant bioaccumulation of lipophilic contaminants. All these characteristics may be particularly useful for the removal of compounds not easily eliminated by conventional wastewater treatment processes. To verify this hypothesis an experimental study was conducted at the pilot scale using a pilot plant installed in the largest wastewater treatment plant of Milan (Milano-Nosedo, Italy). First, we presented results obtained in several preliminary tests in order to evaluate the capability of zebra mussel specimens to survive in different wastewater mixtures, its filtering capacity and the possible influence of bio- and photo-degradation in the abatement of the molecules of interest. Finally, data obtained in the final tests demonstrated a capacity of this filter-feeder to reduce the concentrations of several pharmaceuticals and drugs of abuse higher than that obtained by the simple natural sedimentation, suggesting a possible implementation of the bio-filtration process in wastewater management. © 2014 Elsevier B.V. All rights reserved.

The presence of antibiotic resistant bacteria (ARB) in wastewater was investigated and the role of wastewater treatment plants (WWTPs) in promoting or limiting antibiotic resistance was assessed. Total heterotrophic bacteria (THB) resistance to ampicillin, chloramphenicol and tetracycline was monitored in 3 WWTPs located in Milan urban area (Italy). The effluent was collected at three sampling points along the treatment sequence (WWTP influent, biological effluent, WWTP effluent), being the three WWTPs characterized by different operating parameters in biological process and disinfectants (peracetic acid, UV radiation, sodium hypochlorite). Antibiotic resistance to ampicillin was observed for THB, being the influent to the three WWTPs characterized by different contents of ARB (17-25%). The biological process affected the composition of the bacterial population, determining a change in ampicillin-resistant bacteria presence, although no relations with the operating parameters were identified. PAA was effective in selecting ARB, unlike UV radiation and sodium hypochlorite. No significant resistance was observed for chloramphenicol and tetracycline.

Various factors, such as habitat availability, competition for space, predation, temperature, nutrient supplies, presence of waterfalls, flow variability and water quality, control the abundance, distribution and productivity of stream-dwelling organisms. Each of these factors can influence the response of the density of organisms to a specific environmental gradient, inflating variability and making difficult to understand the possible causal relationship. In our study, we used quantile regression mixed models and Akaike’s information criterion as an indicator of goodness to examine two different datasets, one belonging to Italy and one belonging to Finland, and to detect the limiting action of selected environmental variables. In the Italian dataset, we studied the relationships among five macroinvertebrate families and three physical habitat characteristics (water velocity, depth and substratum size); in the Finnish dataset the relationships between taxa richness and 16 environmental characteristics (chemical and physical). We found limiting relationships in both datasets and validated all of them on different datasets. These relationships are quantitative and can be used to predict the range of macroinvertebrate densities or taxa richness as a function of environmental characteristics. They can be a tool for management purposes, providing the basis for habitat-based models and for the development of ecological indices.

The correct definition of ecosystem needs is essential in order to guide policy and management strategies to optimize the increasing use of freshwater by human activities. Commonly, the assessment of the optimal or minimum flow rates needed to preserve ecosystem functionality has been done by habitat-based models that define a relationship between in-stream flow and habitat availability for various species of fish. We propose a new approach for the identification of optimal flows using the limiting factor approach and the evaluation of basic ecological relationships, considering the appropriate spatial scale for different organisms. We developed density-environment relationships for three different life stages of brown trout that show the limiting effects of hydromorphological variables at habitat scale. In our analyses, we found that the factors limiting the densities of trout were water velocity, substrate characteristics and refugia availability. For all the life stages, the selected models considered simultaneously two variables and implied that higher velocities provided a less suitable habitat, regardless of other physical characteristics and with different patterns. We used these relationships within habitat based models in order to select a range of flows that preserve most of the physical habitat for all the life stages. We also estimated the effect of varying discharge flows on macroinvertebrate biomass and used the obtained results to identify an optimal flow maximizing habitat and prey availability.

PAH (Polycyclic Aromatic Hydrocarbons) analyses were carried out on samples from two Wastewater Treatment Plants (WWTPs) in Lombardy, similar for treatment sequences but fed on different influents: industrial component accounts for 70% at Alto Seveso plant while it is absent in Nosedo plant. Sampling concerned the influent and the effluent from activated sludge reactor and the final effluent after disinfection (ozonation for Alto Seveso and peracetic acid treatment for Nosedo). The concentrations of total PAHs were 5.3 ± 4.0 μg L−1 and 2.4 ± 1.3 μg L−1 in Alto Seveso and Nosedo influent, respectively. The lowest molecular weight PAHs had the highest concentrations in both plants; acenaphthene and naphthalene were the most important components in the influent to Alto Seveso and Nosedo WWTPs, respectively. The higher molecular weight compounds had the lowest concentrations and benzo(g,h,i)perylene and dibenzo(a,h)anthracene were never detected. Most of the PAH load entered biological treatment in dissolved form. For both plants PAHs were mostly removed in the biological section (96.5% and 89.5% for Alto Seveso and Nosedo, respectively), while disinfection had a minor role. Peracetic acid (Nosedo) seemed more efficient than ozone (Alto Seveso) in the removal of PAHs (4.18% and 0.89%, respectively). It is now necessary to confirm this result by using the same effluent for the two disinfection treatments.