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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. [ABSTRACT FROM AUTHOR]

The fluctuation in the number of people in tourist areas affects the wastewater quality and quantity. Constructed wetlands (CWs) aim to simulate physical, chemical, and biological processes occurring in natural environments for wastewater treatment and are considered a sustainable system. The current study aimed at evaluating the effectiveness of in-vessel CWs for supporting the wastewaters treatment plants in periods of overloading. Such approach can be quickly implementable, economic, and the CWs can be fast regenerated in the framework of sustainable good practices. Three pilot scale CWs were prepared in as many containers layering 10 cm of gravel, 60 cm of sand and 10 cm of gravel, and placing pieces of giant reed rhizomes in the upper layers. The bottom of each CW had a tap, and CWs were irrigated with a real municipal sewage three times a week. Before each new irrigation, the tap was opened, and the effluent collected for determining gross parameters, elemental composition, and contaminants of emerging concern (CECs). CWs significantly reduced almost all gross parameters considered and half the CECs, except for a couple of metabolites of corresponding parental compounds. With regards to the potentially toxic elements, all reduced their concentration from the influents to the effluents. The results of this study were promising and highlighted good efficiency of constructed wetlands as pre-treatment of real municipal sewage to reduce the overloading of the wastewater treatment plant. [Display omitted] • Containerized constructed wetlands were used to pre-treat real municipal sewage. • Almost all gross parameters significantly reduced in effluents. • Almost all potentially toxic elements significantly reduced in effluents. • Ten contaminants of emerging concern out of 20 significantly reduced in effluents. • Two metabolites increased their concentration in effluents. [ABSTRACT FROM AUTHOR]

Abstract: Sequencing batch biofilter granular reactor (SBBGR) is a recently developed biological wastewater treatment technology characterised by a very low sludge production, among other numerous advantages. Even if costs for sludge treatment and disposal are mainly dependent on the amount of sludge produced, sludge properties, especially those linked to solid–liquid separation, play a key role as well. In fact, such properties deeply influence the type of treatments sludge has to undergo before disposal and the final achievable solids concentration, strongly affecting treatment and disposal costs. As sludge from SBBGR is a special mixture of biofilm and aerobic granules, no information is available so far on its treatability. This study addresses the characterisation of the sludge produced from SBBGR in terms of some physical properties (settling properties, dewaterability, rheology). The results show that such sludge is characterised by good settling and dewatering properties, adding a new advantage for the full-scale application of SBBGR technology. [Copyright &y& Elsevier]

Abstract: Wastewaters generated by many economically relevant industrial activities contain recalcitrant organic compounds which pass unaltered through biological stage of the treatment plant making it difficult to meet the discharge limits currently in force. Therefore, an additional treatment is usually required to remove these compounds. In this study, the application of ozonation together with biological treatment was investigated. In particular, the effectiveness of biological degradation followed by or integrated with ozonation for treating the effluents produced by three environmentally relevant activities (i.e., leather and textile processing and municipal waste landfilling) are compared in the present paper. The results show that biological treatment followed by ozonation does not guarantee depurative levels sufficient for discharge for landfill leachates and tannery wastewater. On the contrary, thanks to the synergy between biological degradation and ozonation, integrated treatment significantly improves the process performance for all the investigated wastewaters, thus allowing the discharge limits to be met. [Copyright &y& Elsevier]

Abstract: Municipal landfill leachates are considered to be one of the types of wastewater with the greatest environmental impact because of the high concentrations of ammonium, organic matter and salts which characterize them. The most critical steps are usually the removal of recalcitrant pollutants and ammonia. A recently developed process based on ozone enhanced biological degradation, carried out in an aerobic granular biomass system (SBBGR – Sequencing Batch Biofilter Granular Reactor), was tested at lab-scale for treating a typical medium-age landfill leachate. The results have shown that ozonation greatly improves the biological treatment''s effectiveness, allowing the current limits for discharging into the sewer system to be met by using a specific ozone dose of 600mg O3/Linfluent; an operating cost of about 4€ per m3 of leachate was obtained. A strong synergy between chemical and biological oxidation was observed with an O3consumed/CODremoved ratio as low as 0.24. Molecular analysis allowed the microbial composition of the granular biomass to be defined and showed the establishment of stable nitrogen-removing bacterial populations throughout the SBBGR operation. Moreover, the study further confirmed the SBBGR''s ability to effectively overcome the problem of filamentous bacteria overgrowth, which, in contrast, dramatically affects the effluent quality in conventional systems. [Copyright &y& Elsevier]

Abstract: An innovative process based on ozone-enhanced biological degradation, carried out in an aerobic granular biomass system (SBBGR – Sequencing Batch Biofilter Granular Reactor), was tested at pilot scale for tannery wastewater treatment chosen as representative of industrial recalcitrant wastewater. The results have shown that the process was able to meet the current discharge limits when the biologically treated wastewater was recirculated through an adjacent reactor where a specific ozone dose of 120mg O3/Linfluent was used. The benefits produced by using ozone were appreciable even visually since the final effluent of the process looked like tap water. In comparison with the conventional treatment, the proposed process was able to reduce the sludge production by 25–30 times and to save 60% of operating costs. Molecular in situ detection methods were employed in combination with the traditional measurements (oxygen uptake rate, total protein content, extracellular polymeric substances and hydrophobicity) to evaluate microbial activity and composition, and the structure of the biomass. A stable presence of active bacterial populations was observed in the biomass with the simultaneous occurrence of distinctive functional microbial groups involved in carbon, nitrogen and sulphate removal under different reaction environments established within the large microbial aggregates. The structure and activity of the biomass were not affected by the use of ozone. [Copyright &y& Elsevier]

Abstract: The present paper reports the results of an investigation aimed at evaluating the effectiveness of magnesium ammonium phosphate precipitation (MAP), commonly called struvite, for removing ammonia from a mature municipal landfill leachate. MAP precipitation was carried out at laboratory scale by adding phosphoric acid and magnesium oxide as external sources of phosphorus and magnesium, respectively, and regulating the pH at 9.0. The effect of Mg:NH4:PO3 ratio was studied. Due to the low solubility of MgO, a low ammonia removal efficiency (i.e. 67%), with a rather high residual concentration, was obtained when the stoichiometric molar ratio was applied. However, by doubling the amount of magnesium oxide (i.e. by using a molar ratio of 2:1:1), ammonia removal efficiency increased up to 95% with a residual concentration compatible with a successive biological treatment. The struvite produced in the present study showed a composition close to the theoretical one. Furthermore, the precipitate was characterized by a heavy metal content much lower than that of typical raw soil, excluding any concern about heavy metal contamination in the case of its use as a fertilizer. The economic analysis of the process showed that ammonia can be removed at a cost of 9.6€/kg NH4–Nremoved. This value can be greatly reduced, however, if the value of the struvite produced is considered. [Copyright &y& Elsevier]

Abstract: This paper reports the results of an investigation aimed at evaluating the performance of an innovative technology (SBBGR system – Sequencing Batch Biofilter Granular Reactor), characterised by a low sludge production, for treating municipal wastewater at demonstrative scale. The results have shown that even at the maximum investigated organic load (i.e., 2.5 kg COD/m3 d), the plant removed 80% of COD, total suspended solids and nitrogen content with relative residual concentrations lower than the Italian limits for discharge into soil. The process was characterised by a very low sludge production (i.e., 0.12–0.14 kg TSS/kg CODremoved) ascribable to the high sludge age in the system (θc >120 d). Molecular in situ detection methods and microscopy staining procedures were employed in combination with the traditional measurements (oxygen uptake rate and total protein content) to evaluate both the microbial activity and composition, and the structure of the biomass. A stable presence of active bacterial populations (mainly Proteobacteria) was found within compact and dense aggregates. [Copyright &y& Elsevier]

Abstract: This paper reports the results obtained during an investigation aimed at transferring to the demonstrative scale an aerobic granular biomass system (SBBGR – Sequencing Batch Biofilter Granular Reactor) integrated with ozonation for the efficient treatment of tannery wastewater. The results show that the integrated process was able to achieve high removal efficiencies for COD, TSS, TKN, surfactants and colour with residual concentrations much lower than the current discharge limits. Furthermore, the process was characterised by a very low sludge production (i.e., 0.1kg dry sludge/m3 of treated wastewater) with interesting repercussions on treatment costs (about 1€perm3 of wastewater). [Copyright &y& Elsevier]

The electrochemical degradation of six of the most widely used iodinated contrast media was investigated. Batch experiments were performed under constant current conditions using two DSA® electrodes (titanium coated with a proprietary and patented mixed metal oxide solution of precious metals such as iridium, ruthenium, platinum, rhodium and tantalum). The degradation removal never fell below 85% (at a current density of 64 mA/cm 2 with a reaction time of 150 min) when perchlorate was used as the supporting electrolyte; however, when sulphate was used, the degradation performance was above 80% (at a current density of 64 mA/cm 2 with a reaction time of 150 min) for all of the compounds studied. Three main degradation pathways were identified, namely, the reductive de-iodination of the aromatic ring, the reduction of alkyl aromatic amides to simple amides and the de-acylation of N-aromatic amides to produce aromatic amines. However, as amidotrizoate is an aromatic carboxylate, this is added via the decarboxylation reaction. The investigation did not reveal toxicity except for the lower current density used, which has shown a modest toxicity, most likely for some reaction intermediates that are not further degraded. In order to obtain total removal of the contrast media, it was necessary to employ a current intensity between 118 and 182 mA/cm 2 with energy consumption higher than 370 kWh/m 3 . Overall, the electrochemical degradation was revealed to be a reliable process for the treatment of iodinated contrast media that can be found in contaminated waters such as hospital wastewater or pharmaceutical waste-contaminated streams. [ABSTRACT FROM AUTHOR]

Abstract: Textile effluents are characterised by high content of recalcitrant compounds and are often discharged (together with municipal wastewater to increase their treatability) into centralized wastewater treatment plants with a complex treatment scheme. This paper reports the results achieved adopting a granular sludge system (sequencing batch biofilter granular reactor – SBBGR) to treat mixed municipal-textile wastewater. Thanks to high average removals in SBBGR (82.1% chemical oxygen demand, 94.7% total suspended solids, 87.5% total Kjeldahl nitrogen, 77.1% surfactants), the Italian limits for discharge into a water receiver can be complied with the biological stage alone. The comparison with the performance of the centralized plant treating the same wastewater has showed that SBBGR system is able to produce an effluent of comparable quality with a simpler treatment scheme, a much lower hydraulic residence time (11 h against 30 h) and a lower sludge production. [Copyright &y& Elsevier]

Abstract: The Sequencing Batch Biofilter Granular Reactor (SBBGR) is a promising wastewater treatment technology characterized by high biomass concentration in the system, good depuration performance and low sludge production. Its main drawback is the high energy consumption required for wastewater recirculation through the reactor bed to ensure both shear stress and oxygen supply. Therefore, the effect of low recirculation flow on the long-term (38months) performance of a laboratory scale SBBGR was studied. Both the microbial components of the granules, and their main metabolic activities were evaluated (heterotrophic oxidation, nitrification, denitrification, fermentation, sulphate reduction and methanogenesis). The results indicate that despite reduced recirculation, the SBBGR system maintained many of its advantageous characteristics. [Copyright &y& Elsevier]

Abstract The integration of an off-grid solar-assisted heat pump (SHP) and a sequencing batch biofilter granular reactor (SBBGR) for thermal energy recovery from wastewater was assessed by means of a prospective life cycle assessment (LCA) and life cycle costing (LCC), by theoretically scaling up a pilot installation in Bari, Italy, to a full-scale unit designed for 5000 person-equivalents. The LCA and LCC included all activities in the life cycle of the SHP and wastewater treatment plant (WWTP), namely construction, operation and end-of-life. The thermal energy produced by the SHP was assessed as supplying heating and cooling for an air-conditioning system, displacing a conventional air-source heat pump powered by electricity from the grid. This integrated system was compared to a reference situation where wastewater is treated in a conventional WWTP applying activated sludge with no thermal energy recovery system, showing clear environmental benefits in all impact indicators, such as a 42% reduction in greenhouse-gas emissions and a cost reduction of 53%. Several sensitivity analyses confirmed these findings, with the exception of the price rebound effect, which showed that the lower cost of the integrated system could lead to overturning the environmental benefits. As a limitation of the study, the distribution of the supplied air-conditioning to meet a demand off-site the WWTP premises, such as in residential buildings or hotels, was not included. Therefore, our results constitute only a preliminary positive outcome that should be validated in a real-life application. Graphical abstract Image 1 Highlights • A solar-assisted heat pump (SHP) coupled to a sequencing batch biofilter granular reactor supplies an air-conditioning system. • Life cycle assessment and life cycle costing were applied to a scaled-up unit treating sewage for 5000 person-equivalents. • Results show environmental benefits, such as a greenhouse-gas emission reduction by 42% compared to a reference situation. • Life cycle costs are reduced by 53%, leading to an estimated saving of 27€/person-equivalent/year. [ABSTRACT FROM AUTHOR]

Experimental study we present is a full-scale energy recovery system able to extract, by means of a water source heat pump, the leftover thermal bioenergy available in a Sequencing Batch Biofilter Granular Reactor (SBBGR) within the wastewater treatment process. Heat pump compressor engine was powered by a 5.1 kW Photovoltaic plant, thermal energy being recovered is accumulated by two phase change materials tanks (PCM) for heat and cold latent energy storage whose capacity is 0.3 and 0.5 m 3 respectively, thermal energy excess was dissipated through evaporator and condenser devices. Thermal energy extracted from SBBGR ranged from 0 to 14.5 kWh as function of environmental temperature and temperature set point of SBBGR. It was largely affected by environmental temperature during radiation and no deterioration of SBBGR performances were recorded during energy extraction even at lowest temperature set point (i.e. 15 °C). Results obtained demonstrated that SBBGR technology, thanks to its particular process scheme, allows wastewater heat extraction within the treatment process operation, making it actually the only wastewater treatment system able to exchange energy at low temperature (15 °C) without prejudice to treatment performances and, at the same time, to operate a thermal regulation of the treatment reactors, integrating the optimization of thermo-dependent biological processes with energy recovery systems. [ABSTRACT FROM AUTHOR]

The availability of high quality water has become a constraint in several countries. Agriculture represents the main water user, therefore, wastewater reuse in this area could increase water availability for other needs. This research was aimed to provide a simplified scheme for treatment and reuse of municipal and domestic wastewater based on Sequencing Batch Biofilter Granular Reactors (SBBGRs). The activity was conducted at pilot-scale and particular attention was dedicated to the microbiological quality of treated wastewater to evaluate the risk associated to its reuse. The following microorganisms were monitored: Escherichia coli , Salmonella , Clostridium perfringens , somatic coliphages, adenovirus, enterovirus, Giardia lamblia and Cryptosporidium parvum . The possibility of SBBGR enhancement with sand filtration was also evaluated. The SBBGR removed > 90% of suspended solids and chemical oxygen demand, and 80% and 60% of total nitrogen and phosphorous, respectively. SBBGR was also effective in removing microbial indicators, from 1 (for C. perfringens ) up to 4 (for E. coli ) log units of these microorganisms. In particular, the quality of SBBGR effluent was already compatible with the WHO criteria for reuse ( E. coli ≤ 10 3 CFU/100 mL). Sand filtration had positive effects on plant effluent quality and the latter could even comply with more restrictive reuse criteria. [ABSTRACT FROM AUTHOR]

In order to mitigate the potential effects on the human health which are associated to the use of treated wastewater in agriculture, antibiotic resistance genes (ARGs) are required to be carefully monitored in wastewater reuse processes and their spread should be prevented by the development of efficient treatment technologies. Objective of this study was the assessment of ARGs reduction efficiencies of a novel technological treatment solution for agricultural reuse of municipal wastewaters. The proposed solution comprises an advanced biological treatment (Sequencing Batch Biofilter Granular Reactor, SBBGR), analysed both al laboratory and pilot scale, followed by sand filtration and two different disinfection final stages: ultraviolet light (UV) radiation and peracetic acid (PAA) treatments. By Polymerase Chain Reaction (PCR), the presence of 9 ARGs ( ampC , mecA, ermB, sul1, sul2, tetA, tetO, tetW, vanA ) were analysed and by quantitative PCR (qPCR) their removal was determined. The obtained results were compared to the reduction of total bacteria (16S rDNA gene) and of a faecal contamination indicator ( Escherichia coli uidA gene). Only four of the analysed genes ( ermB , sul1, sul2, tetA ) were detected in raw wastewater and their abundance was estimated to be 3.4 ± 0.7 x10 4 - 9.6 ± 0.5 x10 9 and 1.0 ± 0.3 x10 3 to 3.0 ± 0.1 x10 7 gene copies/mL in raw and treated wastewaters, respectively. The results show that SBBGR technology is promising for the reduction of ARGs, achieving stable removal performance ranging from 1.0 ± 0.4 to 2.8 ± 0.7 log units, which is comparable to or higher than that reported for conventional activated sludge treatments. No reduction of the ARGs amount normalized to the total bacteria content (16S rDNA), was instead obtained, indicating that these genes are removed together with total bacteria and not specifically eliminated. Enhanced ARGs removal was obtained by sand filtration, while no reduction was achieved by both UV and PAA disinfection treatments tested in our study. [ABSTRACT FROM AUTHOR]

In the present paper, the effectiveness of a Sequencing Batch Biofilter Granular Reactor (SBBGR) and its integration with different disinfection strategies (UV irradiation, peracetic acid) for producing an effluent suitable for agricultural use was evaluated. The plant treated raw domestic sewage, and its performances were evaluated in terms of the removal efficiency of a wide group of physical, chemical and microbiological parameters. The SBBGR resulted really efficient in removing suspended solids, COD and nitrogen with an average effluent concentration of 5, 32 and 10 mg/L, respectively. Lower removal efficiency was observed for phosphorus with an average concentration in the effluent of 3 mg/L. Plant effluent was also characterized by an average electrical conductivity and sodium adsorption ratio of 680 μS/cm and 2.9, respectively. Therefore, according to these gross parameters, the SBBGR effluent was conformed to the national standards required in Italy for agricultural reuse. Moreover, disinfection performances of the SBBGR was higher than that of conventional municipal wastewater treatment plants and met the quality criteria suggested by WHO ( Escherichia coli < 1000 CFU/100 mL) for agricultural reuse. In particular, the biological treatment by SBBGR removed 3.8 ± 0.4 log units of Giardia lamblia , 2.8 ± 0.8 log units of E. coli , 2.5 ± 0.7 log units of total coliforms, 2.0 ± 0.3 log units of Clostridium perfringens , 2.0 ± 0.4 log units of Cryptosporidium parvum and 1.7 ± 0.7 log units of Somatic coliphages. The investigated disinfection processes (UV and peracetic acid) resulted very effective for total coliforms, E. coli and somatic coliphages. In particular, a UV radiation and peracetic acid doses of 40 mJ/cm 2 and 1 mg/L respectively reduced E. coli content in the effluent below the limit for agricultural reuse in Italy (10 CFU/100 mL). Conversely, they were both ineffective on C. perfringens spores. [ABSTRACT FROM AUTHOR]

Abstract: The application of a biological treatment together with a chemical oxidation process was investigated. In particular, the effectiveness of the biological treatment followed by a UV/H2O2-based advanced oxidation process (AOP) used as an end treatment was compared with that in which the same AOP was integrated with biological degradation for treating a medium age sanitary landfill leachate. The results show that better performance with removal efficiencies higher than 80% for all investigating parameters was obtained when AOP was integrated with the biological treatment, thus allowing the discharge limits to be met. This was due to the biological removal of the biodegradable compounds produced by UV/H2O2 treatment. Instead, UV/H2O2-based AOP biodegradability enhancement gave no advantage when it was used as an end treatment. Finally, the results show that H2O2 alone (i.e., without UV power) was quite ineffective either as a mineralizing or as a biodegradability enhancing agent and that the only reactive species was essentially the hydroxyl free radical OH . [Copyright &y& Elsevier]

Abstract: This paper reports the results obtained using the sequencing batch biofilter granular reactor (SBBGR) for the treatment of the wastewater from a dyeing and finishing factory. The treatment of such a wastewater is challenging as it usually contains considerable amounts of different recalcitrant, toxic and inhibitory pollutants, which results in low biodegradability and in the need for numerous treatment steps. Different operational conditions were tested in order to assess SBBGR performance as a function of the applied organic and hydraulic load and to verify its suitability for on-site dyeing wastewater treatment at each factory. The reported measurements demonstrate how this innovative biological technology exhibits various promising features for this purpose, as good treatment efficiencies can be achieved even at high organic load values (2.4–2.6 kgCOD m−3 d−1) and with hydraulic retention times lower than one day. Furthermore, the treatment is characterized by a sludge production as low as 0.1 kg of dry sludge per kg of COD removed. Therefore, SBBGR has proved to be an effective pre-treatment for dyeing textile wastewater before discharge into municipal sewer system, as it produces a suitable effluent using just only one biological step with high hydraulic and organic loadings and low sludge production. [Copyright &y& Elsevier]