•Removal of pharmaceuticals from wastewaters by cavitation.•Shear-induced cavitation is more efficient than cavitation by Venturi.•Removals up to 79% in wastewater effluent.•Cavitation as a ...pre-treatment yields higher removal of pharmaceuticals.
In this study, the removal of clofibric acid, ibuprofen, naproxen, ketoprofen, carbamazepine and diclofenac residues from wastewater, using a novel shear-induced cavitation generator has been systematically studied. The effects of temperature, cavitation time and H2O2 dose on removal efficiency were investigated. Optimisation (50°C; 15min; 340mgL−1 of added H2O2) resulted in removal efficiencies of 47–86% in spiked deionised water samples. Treatment of actual wastewater effluents revealed that although matrix composition reduces removal efficiency, this effect can be compensated for by increasing H2O2 dose (3.4gL−1) and prolonging cavitation time (30min). Hydrodynamic cavitation has also been investigated as either a pre- or a post-treatment step to biological treatment. The results revealed a higher overall removal efficiency of recalcitrant diclofenac and carbamazepine, when hydrodynamic cavitation was used prior to as compared to post biological treatment i.e., 54% and 67% as compared to 39% and 56%, respectively. This is an important finding since diclofenac is considered as a priority substance to be included in the EU Water Framework Directive.
•Simulation of nutrient loads was done for entire NA watershed consisting of 17 individual watersheds.•Po River watershed is dominating the nutrient loads to the NA.•Agricultural areas and WWTP were ...identified as the major sources of nutrients to the NA.•Proper management decisions were defined to reduce the nutrient loads.
The northern Adriatic (NA) is one of the most productive areas of the Mediterranean Sea with a watershed area spread over four neighboring countries, Italy, Slovenia, Switzerland and Croatia. Up to date research include mainly the nutrient load estimations from the biggest nutrients sources, like the Po River watershed (Italian part). This research aims to estimate the loads from nearly the entire contributing area, including the Italian, the Slovenian and the Croatian part. The ArcView Generalized Watershed Loading Function (AVGWLF) model was applied to simulate nutrient loads from the NA watershed. The model can simulate runoff, sediment and nutrients (nitrogen and phosphorus) loads from the watershed, by taking dispersed and point sources into account. Calibration and validation of the model were performed on the data from 1999 to 2002 and 2003 to 2007, respectively. Comparison between the simulated and measured loads in the Po River watershed shows a good match and thus high reliability of the model. As expected, the Po River dominated the nutrient loads to the NA. However, the results also point to other contributing areas, e.g. smaller watersheds with high intensity of nutrient loads, causing significant local impacts (e.g. Lagoon of Venice). The model also shows that the major sources of nutrients are not only agricultural but also urban areas without proper wastewater treatment (secondary at present). Proper management of these areas, such as introducing suitable (tertiary) wastewater treatment, or other nutrient management measures shall reduce the nutrient loadings to the NA.
Further work is focused to use the model for optimizing the control and management of the activities in the contributing areas, smaller as well as bigger sub-watersheds.
Ballast water is, together with hull fouling and aquaculture, considered the most important factor of the worldwide transfer of invasive non-indigenous organisms in aquatic ecosystems and the most ...important factor in European Union. With the aim of preventing and halting the spread of the transfer of invasive organisms in aquatic ecosystems and also in accordance with IMO’s International Convention for the Control and Management of Ships Ballast Water and Sediments, the systems for ballast water treatment, whose work includes, e.g. chemical treatment, ozonation and filtration, are used. Although hydrodynamic cavitation (HC) is used in many different areas, such as science and engineering, implied acoustics, biomedicine, botany, chemistry and hydraulics, the application of HC in ballast water treatment area remains insufficiently researched. This paper presents the first literature review that studies lab- and large-scale setups for ballast water treatment together with the type-approved systems currently available on the market that use HC as a step in their operation. This paper deals with the possible advantages and disadvantages of such systems, as well as their influence on the crew and marine environment. It also analyses perspectives on the further development and application of HC in ballast water treatment.
► We used machine learning methods to elaborate descriptive and predictive model of phytoplankton dynamics in northeren Adriatic. ► The phytoplankton descriptive model presents the knowledge ...collected over a period of 35 years in a tree like easy-to-read structure. ► The predictive model successfully makes a 15 days forecast of the phytoplankton concentration in north Adriatic.
The northern Adriatic is one of the most productive parts of the Mediterranean Sea due to the nutrient discharges of the Po River. The northwestern part of the northern Adriatic exhibits eutrophic to mesotrophic characteristics with recurrent algal blooms. To contribute to the understanding of eutrophication trends in the northern Adriatic a machine learning tool for induction of models in form of regression trees and in form of set of rules was applied on a data set comprising physical, chemical and biological parameters measured at six stations on the profile from the Po River delta (Italy) to the city of Rovinj on the western coast of Istria (Croatia). Two types of models were successfully elaborated, i.e. (1) the descriptive model
to explain the dynamics of phytoplankton concentration in the northern Adriatic as a result of independent environmental variables, and (2) the predictive model
to predict the phytoplankton concentration. The descriptive model for phytoplankton dynamics integrates and presents in a user-friendly way the knowledge collected through measurements over a period of 35 years. Such presentation contributes to a better understanding of the ecosystem functioning. The predictive model for phytoplankton concentration successfully forecasts the phytoplankton concentration 14 days in advance.
In this work, we develop a library of components for building semi-distributed watershed models. The library incorporates basic modeling knowledge that allows us to adequately model different water ...fluxes and nutrient loadings on a watershed scale. It is written in a formalism compliant with the equation discovery tool ProBMoT, which can automatically construct watershed models from the components in the library, given a conceptual model specification and measured data. We apply the proposed modeling methodology to the Ribeira da Foupana catchment to extract a set of viable hydrological models. By specifying the conceptual model and using the knowledge library, two different hydrological models are generated. Both models are automatically calibrated against measurements and the model with the lower root mean squared error (RMSE) value is selected as an appropriate hydrological model for the selected study area.
•We present a new approach to automated watershed modeling that uses a combination of theoretical and data driven modeling.•We developed a watershed modeling library, compliant with the equation discovery tool ProBMoT.•We applied the proposed modeling methodology to the Ribeira da Foupana catchment to extract viable hydrological models.
The adhesion of bacterial cells to various surfaces is based on physical and chemical interactions between the micro-organisms and the surfaces. The main purpose of this research is to determine the ...effect of material roughness and incubation temperature on the adhesion of bacteria. To determine the adhesion of the bacterial strain of Legionella pneumophila ATCC 33153 to the glass coupons, a spectrophotometric method of measuring the optical density of crystal violet dye that is released from pre-stained bacterial cells attached to the test surface was used. The intensity of adhesion is in positive correlation to the increase in surface roughness (p < 0.05). The adhesion is the greatest at an optimal temperature of 36 °C, whereas the temperature of 15 °C has a bacteriostatic effect and the temperature of 55 °C a bactericidal effect.
The north-western part of the northern Adriatic (NA) exhibits eutrophic to mesotrophic characteristics with recurrent algal blooms and quite unpredictable mucilage events. To contribute to the ...understanding of the mucilage events in the NA a machine learning algorithm for induction of regression trees was applied on a long-term data-set comprising physical, chemical and biological parameters, measured at six stations on the profile from the Po River delta (Italy) to Rovinj (Croatia). A model describing the connection between the TIN/PO4 ratio, considered as a necessary factor and sometimes even a trigger for mucilage events, and the environmental conditions in NA, was elaborated. The model for TIN/PO4 ratio confirmed the assumption that the mucilage events are connected with this ratio, e.g. mucilage events coincides with its high values. This finding indicates that at certain levels of phosphorus limitation (from TIN/PO4 ratio) mucilage event frequency increases. The model also reveals that salinity and temperature are responsible for the changes of the TIN/PO4 ratio and gives an insight on their threshold values which lead to high values of this ratio, further related to mucilage events.Original Abstract: Sjevero-zapadni dio sjevernog Jadrana (SJ) pokazuje eutrofne do mezotrofne karaktaristike sa cestim pojavama cvjetanja algi te prilicno nepredvidljivim cvjetanjima mora. Kako bi se doprinjelo razumijevanju cvjetanja mora u SJ upotrijebljen je algoritam strojnog ucenja za izradu regresijskih stabala na skupu podataka koji sadrzi fizicke, kemijske i bioloske parametre mjerene na sest postaja na profile od delte rijeke Po (Italija) do Rovinja (Hrvatska). Upotrebom strojnog ucenja izraden je model koji opisuje vezu izmedu omjera TIN/PO4 koji se smatra neophodnim, a ponekad i glavnim okidacem za pojave cvjetanja mora te ekoloskih uvjeta u SJ. Dobiveni model za omjer TIN/PO4 potvrduje pretpostavku da su pojave cvjetanja mora povezane sa danim omjerom, tj. pojave cvjetanja mora se podudaraju sa visokim vrijednostima tog omjera. Ovo otkrice ukazuje da se na odredenim razinama ogranicenja fosforom (vidljivo iz omjera TIN/PO4) pojava frekvencije cvjetanja mora povecava. Model takoder otkriva da su salinitet i temperatura odgovorni za promjene omjera TIN/PO4 te daje uvid u njihove granicne vrijednosti koje dovode do visokih vrijednosti ovog omjera, a koji je dalje povezan sa pojavom cvjetanja mora.
The aim of this paper is to discover a model equation for predicting the concentration of the algal species
Peridinium gatunense (Dinoflagellate) in Lake Kinneret. This is a rather difficult task, ...due to the sudden ecosystem changes that occurred in the mid-1990s. Namely, the stable ecosystem (with regular
Peridinium blooms until 1993) underwent changes and has transformed into an unstable system, with cyanobacterial blooms now occurring regularly. This shift in the algal succession is expected to influence attempts to model the lake ecosystem. Namely, the model structure before and after the change is likely to be different. Our modelling experiments were directed to discover a single model equation that can simulate dinoflagellate dynamics in both periods. We apply an automated modelling tool (Lagramge), which integrates the knowledge- and the data-driven modelling approach. In addition we include an expert visual estimation of the models discovered by Lagramge to assist in the selection of the optimal model. The dataset used included time-series measurements of typical data from the periods 1988 to 1992 and 1997 to 1999. Using the data and expert knowledge coded in a modelling knowledge library, Lagramge successfully discovered several suitable mathematical models for
Peridinium. After the expert’s visual estimation and validation of the models, we propose one optimal model capable of long-term predictions.
► Automated modelling method was applied to discover Dinoflagellate model in lake Kinneret. ► The method integrates theoretical and empirical modelling approach. ► The discovered model is in line with the theoretical background knowledge. ► The model successfully simulates the Dinoflagelate over a period of 7 years
Conceptual mathematical modelling of aquatic ecosystems comprises a considerable amount of knowledge reflected through a vast variety of different models that can be found in literature. While there ...is a growing interest in developing unifying documentation systems that allow storage of these models, not much work has been done yet on formalization and storage of the modelling knowledge itself. Such formalization would allow for better sharing and exchange of knowledge between experts on one hand and make it available to computational methods for modeling on the other. The knowledge library we develop here covers the knowledge in the domain of food web modelling in lakes based on differential equations. We illustrate the generality of the knowledge in the library through reconstruction of three well-known models of different complexity from the library, i.e. Vollenweider, R.A., The Scientific Basis of Lake and Stream Eutrophication with Particular Reference to Phosphorus and Nitrogen as Eutrophication Factors. Organisation for Economic Cooperation and Development, Paris, 1968; Imboden, D., Phosphorus model of lake eutrophication. Limnol. Oceanogr. 19 (1974) 297–304 and SALMO model Bendorf, J., A contribution to the phosphorus loading concept. Int. Revue ges. Hydrobiol. 64 (2) (1979) 177–188; Recknagel, F., Systemtechnische Prozedur zur Modellierung und Simulation von Eutrophierungs-prozessen in stehenden und gestauten Gewässern: Sektion Wasserwesen, TU Dresden, Dresden, 1980. We also illustrate how computational methods for model induction from data can benefit from the developed library of knowledge.
Uveljavitev pravnega reda Evropske unije prinaša obsežno strokovno delo tudi v vodno gospodarstvo. Na vodilno, Okvirno direktivo o vodah (WFD) se navezujejo številne druge. Izpolnjevanje določil ...Direktive o ravnanju z odpadnimi komunalnimi vodami (UWWTD) in Direktive o celovitem preprečevanju in omejevanju onesnaževanja (IPPCD) bo tudi v Sloveniji zahtevalo znatne investicije. Področje komunalnih voda na operativni ravni ureja občina, država pa mora izpolnjevati prevzete državne obveznosti do EU. Pravočasno doseganje ciljev zahteva koordinacijo aktivnosti, temelječo na strokovnih podlagah. V UWWTD je eden osnovnih parametrov aglomeracija kot zaokroženo območje tako zgoščene poselitve, da zanj veljajo posebna določila in dinamika iz direktive. Merilo zgoščenosti je število prebivalcev na hektar. Za Slovenijo so bili izdelani najprimernejša mreža eno-hektarskih kvadratnih celic in trije tipi celic poselitve. Območje posamezne aglomeracije sestavljajo celice dveh najgostejših tipov poselitve, ki se stikajo. Površina aglomeracij je mnogo manjša od površine naselij iz RPE, zato so skupne slovenske obveznosti iz direktiv manjše, kar pokaže tudi strokovna podlaga za nacionalni program zbiranja in čiščenja odpadnih komunalnih in padavinskih voda. Izdelane aglomeracije so osnovni element načrtovanja in ukrepanja tudi za druga vodnogospodarska načrtovanja (npr. proti poplavni ukrepi), lahko pa si bi jih uporabilo tudi za programe komunalnega opremljanja in druga razvojna načrtovanja v prostoru.
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