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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 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]

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: 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]

A microcosm study was carried out to evaluate the potential for biodegradation of methyl tert-butyl ether (MTBE) impacting groundwater at a former oil refinery site located in Naples (SW Italy). A screening of aerobic, anaerobic and co-metabolic aerobic conditions was carried out by triplicate batch reactors, using contaminated soil and groundwater from the study site. All microcosms were amended with ammonium and phosphate salts and, if aerobic, they were supplied with excess oxygen throughout the static incubation period of 6 months. Propane, pentane and n-hexane were selected as the primary substrates for co-metabolic treatments. After the initial lag phase (40–60d), quantitative MTBE decay was repeatedly observed in the aerobic set amended only with nitrogen and phosphorus and further fed with MTBE, thus suggesting that the indigenous soil bacteria have the ability to degrade MTBE. All other treatments, i.e., anaerobic and co-metabolic aerobic, resulted unsuccessful after incubation extending up to 190d. Bacterial consortia in the active microcosms were later enriched and further studied through second and third generation batch reactors with no soil, operated under continuous mixing for 5–7 months. MTBE degradation rate progressively increased with reactor operating time, following a zero order kinetics in the concentration range 1–10mgL−1 and leading to a residual concentration of less than 10μgL−1. The calculated maximum biodegradation rate was 20mgMTBE gVSS −1 h−1. An accumulation of nitrite ions also occurred after long operating times, thus inhibiting MTBE degradation. This effect was minimized by replacing ammonium with nitrate. Identified degradation intermediates were tert-butyl alcohol and tert-butyl formate. Fluorescent in situ hybridization was applied for a preliminary microbiological screening of the consortia, suggesting that the detected cocci (about 0.5 and 1.5μm diameter, respectively) and long bacilli with a narrow diameter might be as yet undescribed species. [Copyright &y& Elsevier]

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]