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In order to prevent hydrocarbon discharge at sea from ships, the International Maritime Organization (IMO) enacted the MARPOL 73/78 convention in which any oil and oil residue discharged in wastewater streams must contain less than 5 ppm hydrocarbons. Effective treatment of this petroleum-contaminated water is essential prior to its release into the environment, in order to prevent pollution problem for marine ecosystems as well as for human health. The present paper reports the first results of a field gathering campaign aimed at gaining insight about the treatment of real shipboard slops with a MBR pilot plant, in terms of pilot performance and biomass biokinetic activity. The achieved results highlighted a very high removal of total organic carbon, with biological removal efficiencies (evaluated inside the bioreactor) almost equal to the total removal efficiency (after the membrane filtration), thus suggesting a satisfactory level of biomass activity, also confirmed by the respirometric batch tests.

The United Nations Environment Program defines as waste all the persistent marine debris deposited or abandoned in the sea (marine litter) and beach (beach litter) environment. Thus including all substances or products abandoned or involuntarily dispersed into the sea or on the coastline. It has been estimated that, all around the world, about 10 million tons of waste coming from domestic, commercial and industrial activities reach the seas every year. Moreover, waste floating adrift in the seas and oceans can be carried very far away, reaching different places from the ones they were originated. Further, damage may result to various human activities and equipment, such as navigation, energy production, aquaculture, tourism. In order to identify interventions aimed at reducing the effects of waste inside the sea, an accurate waste characterization both in terms of quantity and quality (composition) is required. The paper reports the results of a study that aimed at characterize the beach litter in the coast of Cadiz, a city in the south-western of Spain. A multivariate cluster analysis was performed to group observed items in dendrograms - obtained on the basis of the frequency on which each type of litter items was found on the beaches in different periods of the year. Results obtained in this study could be adopted as a support to optimize the solid waste collection services and to identify their appropriate fate (recovery and/or disposal). Furthermore, the prevention of waste production, by means of a better organization of the involved activities, can also be obtained.

Tra le varie possibilità di intervento per la rimozione dei nitrati dalle acque di falda, notevole interesse suscita il trattamento in situ dei plume contaminati mediante la realizzazione di biotrincee denitrificanti scavate in situ e naturalmente attraversate dalle acque di falda. Tra i materiali di origine organica che sono stati testati per tali applicazioni, il nocciolino di olive è risultato uno dei più idonei alle potenziali applicazioni di pieno campo. Tale tipo di materiale possiede un elevato contenuto di carbonio organico totale, prossimo al 50%, e una percentuale di lignina prossima al 45% in peso. Il lavoro proposto riporta i risultati di una campagna sperimentale eseguita mediante impianto a scala di laboratorio alimentato in continuo con una soluzione artificialmente contaminata da nitrati (fino a 35 mgNO3-L-1). I rendimenti di denitrificazione ottenuti sono stati elevati (fino al 99%), a fronte di tempi di detenzione idraulica relativamente bassi. Durante l’attività sperimentale è stata monitorata anche la produzione di protossido di azoto, ai fini di valutare il contributo di tali sistemi di trattamento all’emissione di gas climalteranti. In-situ treatment of nitrates contaminated plumes by means of biotrench, filled with materials able to promote the biological denitrification, is nowadays considered as an affordable alternative among the possible applicable technologies. Previous studies highlighted that olive nut, due to its high content of organic carbon as well as of lignin, resulted capable to promote significant removal efficiency. The paper reports the results of an experimental lab scale study carried out with a column filled with a blend of olive nut, sand and soil and feed in continuous with water artificially spiked with nitrates concentration up to 35 mgNO3-N L-1. Despite the low hydraulic retention time the denitrification efficiency resulted very high (up to 99%). Furthermore, the nitrous oxide production was investigated during the experimentation in order to assess the contribution of a such technology to the production of greenhouse gas.

L’uso massiccio di fertilizzanti contenenti azoto è causa dei fenomeni di inquinamento diffuso delle acque di falda. In tale ottica, notevole interesse hanno recentemente riscosso i trattamenti biologici in situ, in grado di promuovere la denitrificazione delle acque di falda mediante la realizzazione di interventi che coniugano efficacia di rimozione e costi relativamente contenuti. Nella nota si riportano i risultati di una ricerca sul processo di denitrificazione eterotrofa, condotta utilizzando come fonte di carbonio tre materiali convenzionalmente considerati di scarto: corteccia di pino, sughero e sansa di olive. Lo studio è stato suddiviso in due fasi: la prima condotta in modalità batch, che ha consentito di valutare le caratteristiche dei substrati utilizzati e l’effettiva capacità di biodegradazione; la seconda condotta su impianti lab-scale in colonna, funzionanti in continuo, che ha consentito di verificare l’effettiva resa degli interventi proposti. Sono state comparate le differenti capacità di rilascio di carbonio organico e le efficienze di denitrificazione conseguibili coi materiali utilizzati. I risultati ottenuti hanno mostrato buoni rendimenti di rimozione, evidenziando sostanziali differenze delle cinetiche di processo tra i vari substrati; in particolare, è risultato che la sansa di olive è il materiale che garantisce le migliori performance di denitrificazione. The intensive use of nitrogen based fertilizers represents the main cause of diffused pollution in groundwater. For this reason, in situ biological groundwater denitrification, coupling good removal efficiency and low operational cost, have obtained up to nowadays an increasing interest from researchers communities. The paper reports the results of a lab-scale investigation, concerning the heterotrophic biological denitrification, sustained by three different carbon source: pine bark, cork and olive pomace. The experimentation has been divided into two phases: the former, focused to investigates the carbon sources features as well as the effective biodegradation capability, carried up in batch; the second carried out by means of lab-scale column continuously fed by water artificially contaminated with nitrates. The achieved results have shown good removal efficiency and also significant differences in kinetics have been highlighted. Particularly, olive pomace was the organic substrate capable to promote the best denitrification performances.

Greenhouse gases (GHGs) emission from wastewater treatment plants (WWTPs) represents an increasing interest in the water industry at the present moment. The biological processes needed for treating wastewater have been found responsible for the unintentional generation of GHGs, such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). The quality and quantity of a GHG emitted from a WWTP can significantly vary with the wastewater treated, the process configuration, and the strategies employed in process control. In the recent past, efforts for monitoring and accounting for GHGs emissions from WWTPs have considerably increased, and classifications of emission type were proposed to facilitate reporting. However, knowledge gaps (e.g., N2O production dynamics) and data availability mar the quantification of a WWTP carbon footprint. Moreover, too often the acquired information is insufficient to understand the dynamics responsible for GHG production. Further, it is not even comparable with measurements from different plants due to the heterogeneity of materials, methods, and instrumentation used. For these reasons, in order to produce useful and comparable information for assessing the carbon footprint of WWTPs, there is a crescent need for a generally accepted methodology for GHGs measurement. This paper proposes a comprehensive protocol for monitoring and accounting for direct and internal indirect GHG emissions related to the aerated compartments of biological WWTPs. The proposed protocol also provides important guidelines for quantifying the contribution of anaerobic processes to the carbon footprint of the plant.

The treatment of municipal landfill leachate by means of aerobic granular sequencing batch reactors (GSBRs) was investigated. The paper reports the results from an experimental campaign lasted 100 days, which has been divided into three periods: cultivation of granular sludge (70 days), operation with semi-fresh (15 day) and diluted landfill leachate (15 day). Two different GSBR configurations were used: a Sequencing Batch Bubble Column reactor and a Sequencing Batch Airlift Reactor. All reactors were operated at Volume Loading Rates (VLRs) between 4.8 and 7.2 g COD /(m 3 ·d). The Chemical Oxygen Demand (COD) removal efficiency varied between 80% and 90% under operation with synthetic wastewater feeding. On the other hand, the COD removal performance decreased to 40-50 % with semi-fresh leachate and to 50-60% with diluted leachate. Regarding nitrogen removal, after granules formation, the performance were satisfactory only when the reactors were fed with synthetic wastewater. Contrarily, the obtained results underline that a specific pre-treatment of ammonium must be applied in order to optimize nitrogen removal. However, the observed results indicate that the landfill leachate can be potentially treated in GSBR bioreactors.

This paper reports on some results of two surveys at sea carried out in the surroundings of a urban wastewater discharge on the coast of the Golfo di Palermo, western Sicily (Italy). At the time of the surveys (year 2005) the stretch of water lying before the central part of the capital town received the untreated wastewater originating from about 200 000 inhabitants, which was discharged on-shore without any prior treatment by the free-surface outfall of “Porta Felice main sewer”. This outfall has crucial importance in the water quality; indeed, the Municipality is steadily implementing a plan featuring an intercepting main sewer along the coast and some pumping stations to connect all the main sewers to the main wastewater treatment plant, located in the SE boundary area of the town. At the moment of the surveys, however, no mitigation measure had been applied yet and the quality of the Gulf was still largely affected by it. Part of the Sanitation Plan was the characterization of the seawater; to this aim, in August and November, 2005, the Università degli Studi di Palermo - on behalf of the Municipality’s Ufficio del Centro Storico - carried out two survey cruises in which the most important seawater quality features were investigated. What will be reported on herein is the part dealing with microbiological indicators, taking the salinity field as background.

The occurrence of nitrates in groundwater is steadily raising concern due to possible health consequences of nitrate ingestion. Biological denitrification in BIO-PRB is the enhancement of a natural process that occurs naturally when bacteria live in an environment void of oxygen with carbon availability. Bio-PRB represent a perspective of development for PRB technique but, despite the fact that this technology has already been widely used for chlorinated solvents, data on denitrification PRBs are still scarce. This paper reports on the results of an experimental study carried out for 214 days on a bench-scale pilot column (10 cm in internal diameter and 100 cm in length with sampling ports at different heights). The column was filled with a mixture of sand, agricultural soil and sawdust (30%, 20% and 50% v/v respectively) and was fed in continuous with a solution maintained at constant concentration of 25 mg/dm3 NO3-N for early 110 days and then gradually increased to 50 mg/dm3 NO3-N. Good nitrate removal performance (up to 99%) were observed with a direct correlation between nitrates removal rate and carbon availability in column.

Composting, mechanical-biological treatment (MBT), biodrying and biostabilization processes of pre-selected organic fraction from municipal solid wastes (OFMSW) have recently become important in municipal solid waste management. Through these treatment processes the potential impacts of the produced wastes and the volume to treat in the landfill are strongly reduced. However, the residual organic matter contained in the treated fraction may provide negative effects when e.g. the treated OFMSW is used as compost. The biological stability degree of the treated matrix provides usefull informations for the final use of it. Indeed, knowing the degree of biological stability of the compost makes possible to evaluate, for example, the re-growth of patogenous or the fitotossicity of the matrix. In this context, the paper presents the monitoring of the quality state (in term of biological stability) of the OFMSW treated in a composting plant in Sicily. The study was performed into different periods: during the plant start-up and during the first subsequent operation period. The assessment of the biological stability of the matrices has been performed throughout the Dynamic Respiration Index (DRI).

Over the last decade new technologies are emerging even more for wastewater treatment. Among the new technologies, a recent possible solution regards membrane bioreactors (MBRs) that represent a promising alternative to conventional processes. Nowadays, the recurrence to mathematical models as reliable tools in planning as well as management issues is of growing interest in Wastewater Treatment Plants field. Regarding MBR modelling, due to the intrinsic complexity and uncertainty in some processes, basic models that can provide a holistic understanding of the technology at a fundamental level are of great necessity. Many mathematical models have been developed for modelling the MBR which basically combine the activated sludge models with the membrane fouling ones. This paper presents the uncertainty assessment of a mathematical model for the simulation of physicalbiological organic removal. In particular, the uncertainty analysis was carried out using the GLUE procedure. The model was applied to a MBR pilot plant located at the Acqua dei Corsari WWTP (Palermo, IT) where water quality data were gathered. In particular, the MBR pilot plant consists of a lab-scale hollow fibre membrane module in submerged configuration. The results showed that the biological process is influenced mainly by the parameters characterizing the formation and degradation of SMP. Instead, regarding the fouling phenomenon, it is mainly influenced by the backwashing efficiency.