A holistic assessment procedure has been used in this study for comparing conventional activated sludge (CAS) and membrane bioreactor (MBR) processes for the treatment of municipal wastewater. Technical, social, administrative, economic and environmental impacts have been evaluated based on 1 year of operational data from three full-scale lines (one MBR and two CAS) working in parallel in a large municipal treatment plant. The comparative assessment evidences a slight advantage of the conventional process in the studied case, essentially due to lower costs, complexity and energy consumption. On the other hand, the MBR technology has a better social acceptance and similar overall environmental footprint. Although these results are influenced by site-specific parameters and cannot be generalized, the assessment procedure allowed identifying the most important factors affecting the final scores for each technology and the main differences between the compared technologies. Local conditions can affect the relative importance of the assessed impacts, and the use of weighting factors is proposed for better tailoring the comparative assessment to the local needs and circumstances. A sensitivity analysis on the weighted final scores demonstrated how local factors are very important and must be carefully evaluated in the decision making process.

This paper aims to demonstrate that integrating biological process and photocatalytic oxidation in a system operated in recycling mode can be a promising technology to treat pharmaceutical wastewater characterized by simultaneous presence of biodegradable and refractory/inhibitory compounds. A lab-scale system integrating a membrane bioreactor (MBR) and a TiO2 slurry photoreactor was fed on simulated wastewater containing 10 mg/L of the refractory drug Carbamazepine (CBZ). Majority of chemical oxygen demand (COD) was removed by the MBR, while the photocatalytic oxidation was capable to degrade CBZ. CBZ degradation kinetics and its impacts on the biological process were studied. The adoption of a recycling ratio of 4:1 resulted in removal of up to 95% of CBZ. Effluent COD reduction, sludge yield increase and respirometric tests suggested that the oxidation products were mostly biodegradable and not inhibiting the microbial activity. These results evidenced the advantages of the proposed approach for treating pharmaceutical wastewater and similar industrial effluents. (C) 2011 Elsevier Ltd. All rights reserved.

Sequencing batch membrane bioreactors can be a good option in up-grading small municipal plant and for industrial applications, maintaining some of the advantages of both original technologies (effluent quality improvement, flexibility and simplicity of realization, operation and control). In this study, the effects of volumetric exchange ratio (VER) and aeration/filtration strategy have been evaluated. Moreover, with the adoption of cycles shorter than 8 h, the opportunity of further simplification of the membrane operation has been tested by choosing a continuous filtration mode instead of the usual short cycle of permeation/relaxation. Two lab-scales MBR equipped with Zenon hollow fiber modules were fed on real primary effluent. For all tests, hydraulic retention time of 10 h and sludge retention time of 60 days have been adopted. Different cycles have been investigated, lasting between 1 and 8 h and all comprising an anoxic phase to allow for denitrification. Operation at low VER resulted in better effluent quality with no limitations to the denitrification phase. For VER >33% a pre-aeration step was required before effluent withdrawal for optimal ammonium removal. Moreover, VER appeared to have limited negative effect on sludge concentration and yield, while the membrane cleaning frequency slightly increased for increasing VER.

Today, several technologies and management strategies are proposed and applied in WWTPs to minimize sludge production and contamination and their techno-economic feasibility has to be carefully evaluated. The increasing interest on this issue is demonstrated by the research financing policies of the European Union. Recently, an important project has been funded, with the aim of finding new routes (hence the project name: ROUTES - Novel processing ROUTES for effective sewage sludge management) for sludge management and so guiding the EU members in their future choices. In this work a technical-economic assessment procedure (benchmarking) for the comparison of sewage sludge management strategies is proposed and some advanced sludge processing routes (Enhanced Sludge Digestion, MBR with side stream Ozonation, Alternated Cycles process) are analyzed.

The biodegradability of different wastewater samples originated from the industrial production of threepharmaceuticals (naproxen, acyclovir, and nalidixic acid) was performed through the standard Zahn-Wellens test. Moreover, the wastewater composition before and during the test was evaluated in termsof parent compounds and main metabolites by LC/MS, and the biodegradability of the parent compoundswas also assessed by performing extra Zahn-Wellens tests on synthetic solutions. The results, besidesshowing the relatively good biodegradability of acyclovir and naproxen, evidenced the masking role ofthe organic matrices, especially in the case of nalidixic acid. The latter compound showed to berecalcitrant and persistent, despite the apparently good performance of the Zahn-Wellens test. Deeperevaluation evidenced that the biodegradation of high concentrations of organic solvents and other biodegradablecompound tended to ''hide" the lack of removal of the target compound.

The enhanced removal of organic compounds from a pharmaceutical wastewater resulting from the productionof an anti-viral drug (acyclovir) was obtained by employing a membrane bioreactor (MBR) and anozonation system. An integrated MBR-ozonation system was set-up by placing the ozonation reactor inthe recirculation stream of the MBR effluent. A conventional treatment set-up (ozonation as polishingstep after MBR) was also used as a reference. The biological treatment alone reached an average CODremoval of 99%, which remained unvaried when the ozonation step was introduced. An acyclovir removalof 99% was also obtained with the MBR step and the ozonation allowed to further remove 99% of theresidual concentration in the MBR effluent. For several of the 28 organics identified in the wastewaterthe efficiency of the MBR treatment improved from 20% to 60% as soon as the ozonation was placed inthe recirculation stream. The benefit of the integrated system, with respect to the conventional treatmentset-up was evident for the removal of a specific ozonation by-product. The latter was efficiently removedin the integrated system, being its abundance in the final effluent 20-fold lower than what obtained whenozonation was used as a polishing step. In addition, if the conventional treatment configuration isemployed, the same performance of the integrated system in terms of by-product removal can only beobtained when the ozonation is operated for longer than 60 min. This demonstrates the effectivenessof the integrated system compared to the conventional polishing configuration.

The accidental or continuous release of residual chlorine in water reclaimed for irrigational purposes could compromisethe crop yield and increase the load of toxic organo-halogenated compounds, posing additional risks forenvironment and human health.This studywas aimed at assessing the consequences of using chlorinatedwater for irrigating lettuce crops grownin pots with two different types of soil.The results show that the accumulation of extractable organo-halogenated compounds (EOX) in soil, roots andleaves is directly related to the chlorine concentration in the irrigation water. The accumulation of EOX insandy soils is not significant, while it reached up to 300% of the control in the silty-clay soil, demonstratingthat the phenomenon is linked to the organicmatter content in the soil. The accumulation of EOX in the soil appearsto play a significant role in subsequent bioaccumulation in cultures irrigated with tap water (long termmemory effect). Chloramines also demonstrated to have similar impacts as the free chlorine from hypochlorite.The consistent bioaccumulation of 400-700 ?gCl kg-1 of EOX in the leaves of crops irrigated with just0.2 mgCl L-1 of residual chlorine, as compared to levels below the detection limit of 75 ?gCl kg-1 in the controlcrops, evidences the potential impact on food chain and human health.

Sewage sludge processing is a key issue in water resource recovery facilities due to the inefficacy of conventional treatments to produce high quality biosolids to be safely used in agriculture. Under this framework, the performances of several enhanced stabilization processes, namely ultrasound-pretreated Mesophilic Anaerobic Digestion (US+MAD), thermophilic anaerobic digestion (TAD), thermal-pretreated TAD (TH+TAD) and ultrasound-pretreated inverse Temperature Phased Anaerobic Digestion (US+iTPAD) have been investigated. Such enhanced processes resulted in higher biogas yields and higher destruction of pathogens with respect to conventional MAD process, thus suggesting their feasibility in full-scale implementation perspectives. A procedure for technical-economic comparison of new sludge processing lines against conventional ones (benchmarking) was developed, based on the definition of technical issues (e.g. reliability, complexity, etc.) which are rated for each situation. Moreover, capital and operating costs were estimated. The enhanced processes analyzed in this work showed some potentially critical items, mainly related to energy balance and reagent consumption.

Removal of pharmaceutical Carbamazepine (CBZ) compound from municipal wastewater has become an issue from the human health and environmental risks point of view, due to its latent recalcitrance and toxicity properties. This study investigated the photodegradation performance of a sequential batch annular slurry photoreactor (SB-ASP) system for the removal of CBZ compound from secondary municipal wastewater. Two different immobilised TiO(2) photocatalysts, namely anatase titanate nanofiber and mesoporous TiO(2) impregnated kaolinite catalyst were applied in the SB-ASP system. Various modes of sequential batch reactor (SBR) cycles, presence of effluent organic matter (EOM) and inorganic ions, mainly nitrate and phosphate that could affect the photodegradation performance of the SB-ASP system were evaluated during the removal of CBZ. High performance size exclusion chromatography revealed that the photocatalytic reaction will preferentially compete and attack on high molecular weight EOM prior to the photodegradation of CBZ. The presence of inorganic ions was found to affect the surface fouling of immobilised photocatalysts used to a different extent, without completely retarding their photoactivity. This study also highlighted that the operation of SB-ASP system was useful to enhance the photodegradation of CBZ compound in a semi-continuous operation without constant catalyst replacement. It is foreseeable that the integration of SB-ASP system with biological treatment systems could provide an advanced treatment option for the recycling and reuse of municipal wastewater. (C) 2011 Elsevier B.V. All rights reserved.

Engineered zinc oxide (ZnO) and silver (Ag) nanoparticles (NPs) used in consumer products are largely released into the environment through the wastewater stream. Limited information is available regarding the transformations they undergo during their transit through sewerage systems before reaching wastewater treatment plants. To address this knowledge gap, laboratory-scale systems fed with raw wastewater were used to evaluate the transformation of ZnO- and Ag-NPs within sewerage transfer networks. Two experimental systems were established and spiked with either Ag- and ZnO-NPs or with their dissolved salts, and the wastewater influent and effluent samples from both systems were thoroughly characterised. X-ray absorption spectroscopy (XAS) was used to assess the extent of the chemical transformation of both forms of Zn and Ag during transport through the model systems. The results indicated that both ZnO- and Ag-NPs underwent significant transformation during their transport through the sewerage network. Reduced sulphur species represented the most important endpoint for these NPs in the sewer with slight differences in terms of speciation; ZnO converted largely to Zn sulfide, while Ag was also sorbed to cysteine and histidine. Importantly, both ionic Ag and Ag-NPs formed secondary Ag sulfide nanoparticles in the sewerage network as revealed by TEM analysis. Ag-cysteine was also shown to be a major species in biofilms. These results were verified in the field using recently developed nanoparticle in situ deployment devices (nIDDs) which were exposed directly to sewerage network conditions by immersing them into a municipal wastewater network trunk sewer and then retrieving them for XAS analysis. (c) 2015 Elsevier Ltd. All rights reserved.

Treated wastewater reuse is increasing in semi-arid regions as a response to the effects of climate change and increased competition for natural water resources. Investigating the fate of bacterial indicators is relevant to assess their persistence in the environment and possible transfer to groundwater or to the food chain. A long-term field-scale experimental campaign and a soil column test were carried out to evaluate the fate of the fecal indicator Escherichia coli (E. coli) in a cultivated soil when contaminated water resources are used for irrigation. For field experiments, fecal contamination was simulated by dosing the indicator to the effluent of a membrane bioreactor, thus simulating a filtration system's failure, and irrigating a test field where grass was grown. The presence of E. coli on grass and topsoil samples was monitored under different scenarios. For evaluating the fate of the same indicator in the subsoil, a set of soil columns was installed next to the field, operated, and monitored for E. coli concentration over time and along depth. Real municipal wastewater was used in this case as source of fecal contamination. Results showed that short- and medium-term effects on topsoil were strongly dependent on the concentration of E. coli in the irrigation water. Limited persistence and no relevant accumulation of the indicator on the grass and in the topsoil were observed. Watering events performed after fecal contamination did not influence significantly the decay in the topsoil, which followed a log-linear model. The trend of the E. coli concentrations in the leaching of the soil columns followed a log-linear model as well, suggesting bacterial decay as the dominant mechanism affecting the underground indicator's concentration.

Three innovative technical solutions for sludge minimization in wastewater treatment are under investigation in Routes project ("Novel processing routes for effective sewage sludge management") co-funded by the European Commission in the framework of the Seventh Framework Programme: 1) the use of Sequencing Batch Biofilter Granular Reactor (SBBGR) based technology, 2) the integration of membrane bioreactors with anaerobic side-stream process (MBR+AnSSR), and 3) the adoption of alternate cycles process applied in the sludge line (ACSL).The results obtained have shown that: 1) SBBGR is able to reduce up to 75% the sludge production during raw municipal wastewater treatment, and to offer satisfactory performances allowing the discharge limits to be met; 2) MBR+AnSSR offers a sludge production reduction comparable or even greater than that obtained in a conventional system (MBR + aerobic digestion), and 3) ACSL permits to obtain an Observed Yield reduction on average equal to 46% compared with the expected one, without a worsening of the final effluent quality.

Squarebop I bacteriorhodopsin is a light-activated proton pump present in the membranes of the archeonHaloquadratum walsbyi, a square-shaped organism representing 50-60% of microbial population in thecrystallizer ponds of the coastal salterns.Here we describe: (1) the operating mode of a bioreactor designed to concentrate the saltern biomassthrough a microfiltration process based on polyethersulfone hollow fibers; (2) the isolation of SquarebopI bacteriorhodopsin from solubilized biomass by means of a single chromatographic step; (3) tightlybound lipids to the isolated and purified protein as revealed by MALDI-TOF/MS analysis; (4) the photoactivityof Squarebop I bacteriorhodopsin isolated from environmental samples by flash spectroscopy.Yield of the isolation process is 150 lg of Squarebop I bacteriorhodopsin from 1 l of 25-fold concentratedbiomass. The possibility of using the concentrated biomass of salterns, as renewable resourcefor the isolation of functional bacteriorhodopsin and possibly other valuable bioproducts, is brieflydiscussed.

Purpose: Nitrogen, phosphorus and carbon originating from wastewater and sludge can, depending on their partitioning during wastewater treatment, either become available as potential resources or leave as emissions. Several reviews have highlighted the dependence of life cycle assessment (LCA) results on the inventory data. To provide a foundation for future assessments of systems in which resources are utilised from wastewater or sludge, this paper identifies common practice and highlights deficiencies in the selection and quantification of nitrogen, phosphorus and carbon containing flows. Methods: Inventories of major direct flows containing nitrogen, phosphorus and carbon in 62 studies on wastewater and sludge management operations have been reviewed. A special focus was put on flows of nitrogen, phosphorus and carbon originating from the wastewater and sludge and on how these are either leaving the system as emissions and hereby contributing to environmental impacts, or how potential resource flows of these elements are accounted for, in particular when sludge is used in agriculture. Results and discussion: The current study shows a large variation between studies regarding what resource and emission flows were included in inventories on wastewater and sludge treatment, the type of data used (primary or secondary data) and, when flows have been modelled rather than measured, how the modelling has been done. Except for nitrogen and phosphorus emissions via the effluent, which were generally quantified using measured data or data modelled to represent the specific situation, direct emissions to air from the water and sludge lines at the wastewater treatment plant were mostly estimated using secondary data, sometimes of poor data quality. In systems where resources were recovered through agricultural application of sludge, studies often credited the system for avoided use of mineral fertiliser, but the considered replacement ratio differed. Conclusions: The current review identified increased completeness and specificity in the modelling of the evaluated flows as particularly relevant for future studies and highlighted a need for improved transparency of data inventories. The review can be used as a support for LCA analysts in future studies, providing an inventory of common practices and pinpointing deficiencies, and can thereby support more conscious and well-motivated choices as regard which flows to include in assessments and on the quantification of these flows.

This paper describes the preliminary assessment of a platform of innovative upgrading solutions aimed at improving sludge management and resource recovery in wastewater treatment plants. The effectiveness of the upgrading solutions and the impacts of their integration in model reference plants have been evaluated by means of mass and energy balances on the whole treatment plant. Attention has been also paid to the fate of nitrogen and phosphorus in sludge processing and to their recycle back to the water line. Most of the upgrading options resulted in reduced production of dewatered sludge, which decreased from 45 to 56 g SS/(PE x day) in reference plants to 14-49 g SS/(PE x day) in the upgraded ones, with reduction up to 79 % when wet oxidation was applied to the whole sludge production. The innovative upgrades generally entail an increased demand of electric energy from the grid, but energy recovery from biogas allowed to minimize the net energy consumption below 10 kWh/(PE x year) in the two most efficient solutions. In all other cases the net energy consumption was in the range of -11 % and +28 % of the reference scenarios.

Membrane filtration was investigated at field scale in order to assess its effectiveness for reusing municipal effluents in agriculture. The study was started on April 2002 and ended on September 2007, as part of a national R&D project (AQUATEC). Preliminary results, which we already reported elsewhere, concerned the first two project years while this paper refers to the subsequent period. Three different crops (processing tomato, fennel and lettuce) were grown in rotation at a test field located in Apulia (Southern Italy) and irrigated with membrane filtered municipal secondary effluents. The quality of the reclaimed water was monitored chemically and microbiologically, and compared with conventional water pumped from a local well. Both water sources were used in parallel for irrigating two plots of the test field. The results showed that the microbiological quality of the treated wastewater was comparable to or even higher than that of the conventional source. Protozoan (oo)cysts were experimentally identified as effective indicators of possible failures of the filtration system. Moreover, long term heavy metals accumulation trends were monitored in soil and crops, showing that despite some lead and copper accumulation in the soil, no measurable increase of these metals was observed in the edible parts of the crops.

Bacteria of activated sludge for wastewater treatment degrade and oxidize the polluting matter. They can also select and adapt to metabolize complex substrates. The knowledge of metabolic pathways for pollutant degradation becomes decisive to manage wastewater treatment plants. These pathways are strongly related to the bacterial enzymatic activity, that can be revealed through protein measurement. The protein set of a cell represents its functional picture in a given situation, and differently from the gene set it may change significantly according to environmental conditions. In biological wastewater treatment plants, metaproteomics can be applied to find the key enzymes or proteins of a process, and can reveal unexpected biochemical pathways. In every case it can show the metabolic dynamics of an entire consortium in different or targeted conditions.In order to evaluate the behavior of microbial consortia under well determined operating conditions, metaproteomics has been applied for the characterization of the biomass of a membrane bioreactor (MBR) treating an industrial wastewater (Salerno et al., 2016).The present work reports on the effects of changes in wastewater composition/supply on the biomass in terms of its functional response as measured through metaproteomics.

The legislative framework in force in Europe entails restrictive effluent standards for sensitive areas, and quite severe restrictions on the properties of residual sewage sludge, both for landfill disposal and for agricultural use. Several technologies and management strategies have been proposed and applied in wastewater treatment plants to minimise sludge production and contamination. However, their techno-economic and environmental performance has to be carefully evaluated. The ROUTES project, funded within the EU Seventh Framework programme, aims to find new routes for wastewater treatment and sludge management and thereby guide EU members in their future choices. Within this project, the authors have developed and applied a procedure for techno-economic- environmental assessment of new wastewater and sludge processing lines in comparison to reference plants. The reference plants are model conventional plants that experience different types of problems and the new plants are modified plants in which different innovative technologies have been added to solve these problems. The procedure involves a rating of selected technical issues, estimates of operating costs and an assessment of environmental impacts from a life cycle perspective. This paper reports on the procedure and shows examples of results.

In order to meet the environmental legislative framework in force in Europe and reduce sludge processing and disposal costs, several sludge treatment technologies and management strategies have been proposed in the last two decades. The evaluation of their technical and economic suitability, case by case, may be a challenge, since many aspects are involved, so that a robust decision support system should be used. Within the ROUTES project (founded within the EU Seventh Framework Programme), the authors have developed an assessment procedure which allows rating several technical factors (such as system reliability, complexity, safety aspects, modularity, etc.) and estimating capital and operating costs, in case a plant is being upgraded. The comparison between the original (reference) plant and the modified configuration informs about technical hot spots (which are expressed by a traffic light-type colour code) and cost gaps resulting from the implementation of the new solution. © 2014 Springer-Verlag Berlin Heidelberg.

Chemical-biological degradation of a widely spread antibacterial (nalidixic acid) was successfully obtained by an integrated membrane bioreactor (MBR)-ozonation process. The composition of the treated solution simulated the wastewater from the production of the target pharmaceutical, featuring high salinity and a relevant concentration of sodium acetate. Aim of treatment integration was to exploit the synergistic effects of chemical oxidation and bioprocesses, by adopting the latter to remove most of the COD and the ozonation biodegradable products. Integration was achieved by placing ozonation in the recirculation stream of the bioreactor effluent. The recirculation flow rate was three-fold the MBR feed. and the performance of the integrated system was compared to the standard polishing configuration (single ozonation step after the MBR). Results showed that the introduction of the ozonation step did not cause relevant drawbacks to both biological and filtration processes. nalidixic acid passed undegraded through the MBR and was completely removed in the ozonation step. Complete degradation of most of the detected ozonation products was better achieved with the integrated MBR-ozonation process than using the sequential treatment configuration, i.e. ozone polishing after MBR, given the same ozone dosage.

The treatment of a pharmaceutical wastewater resulting from the production of an antibacterial drug (nalidixic acid) was investigated employing a membrane bioreactor (MBR) integrated with either ozonation or UV/H2O2 process. This was achieved by placing chemical oxidation in the recirculation stream of the MBR. A conventional configuration with chemical oxidation as polishing for the MER effluent was also tested as a reference. The synergistic effect of MBR when integrated with chemical oxidation was assessed by monitoring (i) the main wastewater characteristics, (ii) the concentration of nalidixic acid, (iii) the 48 organics identified in the raw wastewater and (iv) the 55 degradation products identified during wastewater treatment. Results showed that MBR integration with ozonation or UV/H2O2 did not cause relevant drawbacks to both biological and filtration processes, with COD removal rates in the range 85-95%. Nalidixic acid passed undegraded through the MBR and was completely removed in the chemical oxidation step. Although the polishing configuration appeared to give better performances than the integrated system in removing 15 out of 48 secondary organics while similar removals were obtained for 19 other compounds. The benefit of the integrated system was however evident for the removal of the degradation products. Indeed, the integrated system allowed higher removals for 34 out of 55 degradation products while for only 4 compounds the polishing configuration gave better performance. Overall, results showed the effectiveness of the integrated treatment with both ozone and UV/H2O2.

Today, several technologies and management strategies are proposed and applied in WWTPs to minimise sludge production and contamination and their techno-economic feasibility has to be carefully evaluated. In this work (which is being conducted within the European Union project 'ROUTES'), based on bench results, a mass balance was drawn for a WWTP (500,000 PE), where it was supposed to install a wet oxidation (WO) stage for sludge minimisation. The design of treatment units and the estimation of capital and operation costs were then performed. Subsequently, a procedure for technical-economic assessment was developed. Basically, this procedure consists in the definition and ranking of several technical (e.g., reliability of the technology, complexity and integration with the existing facilities, amount of residues to be disposed of or recovered, etc.) and economic aspects. Preliminary results have shown WO to be a suitable solution for sludge minimisation.

Today, several technologies and management strategies are proposed and applied in WWTPs tominimize sludge production and contamination and their techno-economic feasibility has to becarefully evaluated. Wet oxidation (WO) process is an alternative solution to conventionalincineration for converting sewage sludge to inert residues. In this work (which is being conductedwithin the EU project "ROUTES"), based on bench scale tests results, a mass balance was drawnfor a WWTP (500,000 PE), where it was supposed to install a WO stage for sludge minimization.The design of treatment units and the estimation of capital and operation costs were thenperformed. Subsequently, a procedure for technical-economic assessment (benchmarking) wasdeveloped. Basically, this procedure consists in the definition and ranking of several technical (e.g.reliability of the technology, complexity and integration with the existing facilities, amount ofresidues to be disposed of or recovered,...) and economic aspects. Preliminary results have shownWO to be a suitable solution for sludge minimization.

The legislative framework in force in Europe requires the achievement of restrictive effluent standards for sensitive areas, and quite severe restrictions of properties of residual sewage sludge, both for landfill disposal and for agricultural use. Several technologies and management strategies have been proposed and applied in wastewater treatment plants to minimize sludge production and contamination. However, their techno-economic and environmental feasibility has to be carefully evaluated. The ROUTES project, funded within the EU 7th framework programme, aims to find new routes (hence the project name) for wastewater treatment and sludge management and so guiding the EU members in their future choices. Within this project, the authors have developed and applied a procedure for technical-economic-environmental assessment of new sludge processing lines in comparison to reference cases. The reference cases are model conventional plants that experience different types of problems and the new cases are modified such plants in which different innovative technologies have been added to solve these problems. The procedure involves a rating of selected technical issues (e.g. system reliability, complexity, safety aspects, modularity, etcetera), and estimates of capital and operating costs, as well as environmental impacts from a life cycle perspective. This paper reports on the procedure and some results.

Today, several technologies and management strategies are proposed and applied in wastewater treatment plants (WWTPs) to minimise sludge production and contamination. In order to avoid a shifting of burdens between different areas, their techno-economic and environmental performance has to be carefully evaluated. Wet oxidation (WO) is an alternative solution to incineration for recovering energy in sewage sludge while converting it to mostly inorganic residues. This paper deals with an experimentation carried out within the EU project " ROUTES" . A mass balance was made for a WWTP (500,000 person equivalents) in which a WO stage for sludge minimisation was considered to be installed. Both bench- and full-scale test results were used. Design of treatment units and estimation of capital and operational costs were then performed. Subsequently, technical and economic aspects were evaluated by means of a detailed methodology which was developed within the ROUTES project. Finally, an assessment of environmental impacts from a life cycle perspective was performed. The integrated assessment showed that for the specific upgrade considered in this study, WO technology, although requiring a certain increase of technical complexity at the WWTP, may contribute to environmental and economic advantages. The paper provides guidance in terms of which aspects need a more thorough evaluation in relation to the specific case in which an upgrade with WO is considered. © 2014 Springer-Verlag Berlin Heidelberg.

In order to support decision-making in design of wastewater and sludge management within the European Union, the EU FP7 project ROUTES has performed technical development aimed at sludge minimisation, the enabling of agricultural use of sludge and sludge resource recovery. Technical, economic and environmental assessment has been performed for case studies in which model reference plants of different size and design have been upgraded to solve different common problems. This paper reports on the methodology used in the assessment with examples of obtained results.

In order to support decision-making in design of wastewater and sludge management within the European Union, the EU FP7 project ROUTES has performed technical development aimed at sludge minimisation, the enabling of agricultural use of sludge and sludge resource recovery. Technical, economic and environmental assessment has been performed for ten case studies in which model (non-existent) reference plants of different size and configuration, representative of real wastewater treatment plants in Europe, have been considered to be upgraded to solve different common problems, based on the new knowledge from the technology development carried out within the project. This paper reports on the methodology used in the assessment with examples of obtained results for three of the case studies. The methodology in particular highlights some critical points that need further attention when similar upgrading is considered in real cases.

In this work we have performed a feasibility study of two upgrading alternatives for sewage sludge stabilization aimed to the reduction of the produced sludge and to the improvement of its qualitative characteristics with respect to its final destination: agricultural use or incineration. The first upgrading (1) proposes the separated thickening: primary sludge is thickened by gravity while dynamic thickening is applied to secondary sludge. The second upgrading (2) introduces a post-aerobic digestion stage (after the anaerobic one), in addition to separate thickening. Technical-economic and environmental assessments have been performed in comparison to a conventional wastewater treatment plant, which operates with gravity thickening and anaerobic digestion of mixed sludge. In the post-aerobic stage, operated with intermittent aeration, additional volatile solids removal of 45% and nitrification and denitrification efficiencies of 97% and 70%, respectively, were achieved. Both upgrading alternatives gained a positive technical evaluation with the only exceptions of the item "Thermal energy consumption" in upgrading 1 for agricultural reuse, and, to a minor extent, the "Energy available for external recovery" for incineration in both upgrading options. Cost analysis showed that the two upgrading alternatives are generally cheaper than the conventional plant, even if the results are dependent on local conditions, which have to be considered. Results of the environmental assessment showed that the upgrades with incineration perform better than the reference for all impact categories except freshwater eutrophication, with upgrading 2 as the best option. For the agricultural use, different results were obtained for the different impact categories with critical aspects mainly related to phosphorus and ammonia emissions for upgrading 1.

In this paper, the potential impacts in the techno-environmental performance of a municipal wastewater treatment plant with integrated mixed-microbial-culture polyhydroxyalkanoate (PHA) production are presented for the first time. A life cycle assessment was conducted based on mass and energy balances. The techno-environmental performance was evaluated for five wastewater treatment configurations: a reference case and four alternative processes producing PHA-rich biomass using influent municipal wastewater as the only organic carbon source. The integration of PHA-rich biomass production into a municipal wastewater treatment plant with sludge digestion sustains the overall conversion yield for total products of biogas and PHA-rich biomass (around 0.26 gCOD products per influent gCOD treated). PHA production integration has the potential to improve the overall environmental performance with respect to the reference case. Even when no benefits were accounted for substitutions related to the biogas and PHA-rich biomass, similar or improved environmental performances were estimated for all four alternatives for global warming potential, acidification potential, terrestrial eutrophication potential, and photo-oxidant formation potential. When benefits were accounted from substitutions of electricity and heat co-generated from biogas and of PHA-rich biomass by pure-culture PHA-rich biomass from sugar fermentation, gains were even higher due to the diversion of carbon from biogas to PHA-rich biomass. Freshwater and marine eutrophication potentials were dependent on effluent specifications. Case-by-case process configurations influence the mass and energy balance and trade-offs of process integration. The production and export of PHA-rich biomass decreased the aeration requirements for COD and nitrogen removal; however, increased demands for heat, power and chemicals were incurred for the generation of volatile fatty acids from primary solids fermentation. The choice of nitrogen-removal approach (nitrification-denitrification vs. anammox) also impacted energy consumption. Using influent wastewater as the sole carbon supply, the energy balance and PHA production were sensitive to the efficiency of primary treatment and available flux of volatile fatty acids into PHA production. Other regional inputs of organic residuals may improve carbon recovery in the treatment facility. The improved environmental performance of the treatment configurations motivates the idea that individual municipal wastewater treatment plants may become suppliers of renewable raw materials of higher value than that of biogas and/or energy and heat today.

Wastewater treatment facilities are increasingly being considered as centralized installations where various resources can be recovered from the sewage. Novel technological solutions are already available for achieving this goal. However, their application to upgrade existing plants can be far more challenging than building new dedicated plants. While the scientific literature is generally focused on testing and comparing the recovery options, this work was aimed at giving a holistic evaluation of the actual impacts of upgrading existing facilities. Commercially available systems were considered for retrofitting two plants of different size (50,000 and 500,000 population equivalents) and achieving either energy self-sufficiency or material recovery. Based on mass and energy balances, a detailed evaluation of technical, social, economic, and administrative aspects was carried out. Environmental aspects were also included, adopting a simplified approach. It turned out that energy self-sufficiency (external energy supply reduced down to about 10% of the total need) is not far away to be achieved, with moderate techno-economic implications, especially when the plant is already equipped with primary sedimentation and anaerobic digestion. Integral recovery of treated effluent, sludge and nitrogen can also be pursued in large facilities, while several potential criticalities arise for medium-sized plants. The adopted procedure evidenced critical aspects that are often disregarded in the decision process: this may suggest where to address efforts in evaluating real situations.

This paper is aimed at evaluating, from a techno-economic and environmental point of view, the performance of an existing wastewater treatment plant in which the traditional biological section is upgraded with an innovative Sequencing Batch Biofilter Granular Reactor. Two scenarios were simulated in order to model and assess the performances of conventional (CAS, Conventional Activated Sludge) and innovative solutions, based on mass balances, techno-economic evaluation and environmental assessment. The results showed that converting the activated sludge process into an {SBBGR} allows to achieve a drastic reduction in sludge production (up to 75% as volatile suspended solids). Furthermore, the secondary sedimentation and sludge stabilization units can be dismissed, reducing the area requirement (up to 50%). The technical assessment is mainly positive, with the electric energy consumption being the only critical item. The higher energy demand of the upgraded plant (about 25% more than the conventional treatment) is mainly associated with the recycle flow in the {SBBGR} system. Although the economic sustainability of the upgraded plant depends on local conditions, it can be considered to be likely favourable: sludge disposal and materials & reagents costs, together with the investment for plant reconstruction are those items that should be carefully evaluated before upgrading the {CAS} plant with {SBBGR} technology. The environmental assessment shows also mostly positive results, although it points to the increased phosphorus concentration in the effluent as a potentially critical issue and it highlights the electricity use and the increased nitrous oxide generation as other matters that need to be carefully checked in real case application.

Nowadays, several technologies and management strategies are proposed for upgrading wastewatertreatment plants (WWTPs) in order to improve sludge stabilization or minimize sludge production. Inorder to make sure that this leads to overall improvements, their techno-economic and environmentalperformance has to be carefully evaluated. In response to this, the techno-economic and environmentalperformance was assessed for a considered model reference WWTP upgraded with separate treatmentand disposal for primary and secondary sludge to provide guidance to research, policy and investmentefforts. This paper departs in an experimental campaign carried out within the EU project "ROUTES" anddescribes an assessment of an upgrade of a WWTP, involving wet oxidation of primary sludge andthermophilic anaerobic digestion (integrated with thermal hydrolysis pre-treatment) for secondarysludge. The reference plant and the upgrade implied different disposal routes for the resulting sludges:incineration for the stabilized sludge deriving from the reference WWTP; agricultural land applicationfor the secondary stabilized sludge from the upgraded plant and landfilling for the solid residue derivingfrom the wet oxidation process (as non-hazardous waste).The mass balance carried out for both reference and upgraded WWTPs showed a reduction of totalsludge production (up to 45%) for the upgraded WWTP. The additional energy demand of the upgradedsolution (þ22.4 Wh/(PE d), PE: population equivalent) was partially balanced by the electric energyproduced by combined heat and power unit installed in the upgraded WWTP (18.08 Wh/(PE d)). Theintegrated assessment showed that the upgraded solution, although resulting in an increase of WWTPtechnical complexity, may contribute to environmental and economic advantages. The paper providesguidance in terms of which aspects need a more thorough evaluation when this upgrade is considered inreal cases.