Filtration of effluents for microirrigation systems

Clogging, measured through head loss across filters, and the filtration quality of different filters using different effluents were studied. The filters used were: 115, 130, and 200 m disc filters; 98, 115, 130, and 178 m screen filters; and a sand filter filled with a single layer of sand with an effective diameter of 0.65 mm. The filters were used with a meat industry effluent and secondary and tertiary effluents of two wastewater treatment plants. It was observed that clogging depended on the type of effluent. With the meat industry effluent, the poorest quality effluent, disc filters clogged more than the other filter types. When the wastewater treatment plant effluents were used, the disc filters showed less frequent clogging. Several physical and chemical parameters, such as total suspended solids, chemical oxygen demand, turbidity, electrical conductivity, pH, and number of particles, were analyzed in the effluents at the entry and exit points of the filters. In general, filters did not reduce the values of the main clogging parameters to a great degree. It was found that the parameter that explained the clogging, expressed as Boucher’s filterability index, was different depending on the type of effluent and filter. The best quality of filtration was achieved with a sand filter when the meat industry effluent was used. No significant differences were observed between the quality of filtration of disc and screen filters when operating with the secondary and tertiary effluents

Effect of flushing frequency on emitter clogging in microirrigation with effluents

Flushing is an important maintenance task that removes accumulated particles in microirrigation laterals that can help to reduce clogging problems. The effect of three dripline flushing frequency treatments (no flushing, one flushing at the end of each irrigation period, and a monthly flushing during the irrigation period) was studied in surface and subsurface drip irrigation systems that operated using a wastewater treatment plant effluent for three irrigation periods of 540 h each. The irrigation systems had two different emitters, one pressure compensating and the other not, both molded and welded onto the interior dripline wall, placed in laterals 87 meters long. Dripline flow of the pressure compensating emitter increased 8% over time, while in the nonpressure compensating emitter, dripline flow increased 25% in the surface driplines and decreased 3% in the subsurface driplines by the emitter clogging. Emitter clogging was affected primarily by the interactions between emitter location, emitter type, and flushing frequency treatment. The number of completely clogged emitters was affected by the interaction between irrigation system and emitter type. There was an average of 3.7% less totally clogged emitters in flushed surface driplines with the pressurecompensating emitter as compared to flushed subsurface laterals with the nonpressure compensating emitter

Influence of EfOM on the oxidation of micropollutants by Ozone and UV/H2O2 in secondary effluents

The aim of this work was to study the influence of effluent organic matter (EfOM) on micropollutants removal by ozone and UV/H2O2. To perform the experiments, deionized water and municipal secondary effluents (SE) were artificially contaminated with atrazine (ATZ) and treated by the two proposed methods. ATZ concentration, COD and TOC were recorded along the reaction time and used to evaluate EfOM effect on the system efficiency. Results demonstrate that the presence of EfOM can significantly reduce the micropollutant removal rate due to competition of EfOM components to react with radicals and/or molecular ozone. The hydroxyl radical scavenging caused by EfOM was quantified as well as the contribution of molecular ozone and �OH radicals during the ozonation of SE. EfOM components promoted higher inhibition of ATZ oxidation by hydroxyl radicals than by molecular ozone.

Determinació de compostos orgànics contaminants en aigües residuals industrials

La determinació de compostos orgànics contaminants en aigües residuals d’origen urbà i industrial és un tema que ha suscitat un creixent interès, tant des del punt de vista del problema mediambiental que es deriva de l’abocament d’aquestes aigües al medi aquàtic públic com des de la perspectiva de reutilització de les aigües tractades en processos industrials. La majoria d’aquests contaminants no s’eliminen completament en plantes de tractament d’aigües convencionals, pel que s’han de controlar. Aquest fet implica desenvolupar nous processos de tractament que permetin millorar l'eficiència de l'eliminació de les plantes de tractament convencionals. Per tal d'investigar la presència d'aquests compostos contaminants a baixes concentracions és necessari desenvolupar nous mètodes analítics altament sensibles. En el nostre projecte s'han desenvolupat diferents mètodes analítics per determinar compostos orgànics contaminants en aigües residuals provinents de plantes de tractament d'aigües industrials, urbanes i plantes potabilitzadores, utilizant principalment la microextracció en fase sòlida (SPME) seguida de la cromatografia de gasos acoblada a un espectròmetre de masses (GC-MS). S'ha estudiat la presència de diferents famílies de compostos en aquestes aigües, com són: ftalats, amines alifàtiques primàries i nitrosamines. A més a més, s'han desenvolupat mètodes analítics per determinar amines alifàtiques primàries en llots actius provinents de diferents tipus de plantes de tractament d'aigües i plantes potabilitzadores.

Effluent particle removal by microirrigation system filters

The aim of this work was to determine whether the filters used in microirrigation systems can remove potentially emitter-clogging particles. The particle size and volume distributions of different effluents and their filtrates were established, and the efficiency of the removal of these particles and total suspended solids by screen, disc and sand filters determined. In most of the effluents and filtrates, the number of particles with a diameter > 20 μm was minimal. By analysing the particle volume distribution it was found that particles larger than the disc and screen filter pores appeared in the filtrates. However, the sand filter was able to retain particles larger than the pore size. The filtration efficiency depended more on the type of effluent than on the filter. It was also found that the particle size distribution followed a potential law. Analysis of the β exponents showed that the filters did not significantly modify the particle size distribution of the effluents

Self-Organising Maps and Correlation Analysis as a Tool to Explore Patterns in Excitation-Emission Matrix Data Sets and to Discriminate Dissolved Organic Matter Fluorescence Components

Dissolved organic matter (DOM) is a complex mixture of organic compounds, ubiquitous in marine and freshwater systems. Fluorescence spectroscopy, by means of Excitation-Emission Matrices (EEM), has become an indispensable tool to study DOM sources, transport and fate in aquatic ecosystems. However the statistical treatment of large and heterogeneous EEM data sets still represents an important challenge for biogeochemists. Recently, Self-Organising Maps (SOM) has been proposed as a tool to explore patterns in large EEM data sets. SOM is a pattern recognition method which clusterizes and reduces the dimensionality of input EEMs without relying on any assumption about the data structure. In this paper, we show how SOM, coupled with a correlation analysis of the component planes, can be used both to explore patterns among samples, as well as to identify individual fluorescence components. We analysed a large and heterogeneous EEM data set, including samples from a river catchment collected under a range of hydrological conditions, along a 60-km downstream gradient, and under the influence of different degrees of anthropogenic impact. According to our results, chemical industry effluents appeared to have unique and distinctive spectral characteristics. On the other hand, river samples collected under flash flood conditions showed homogeneous EEM shapes. The correlation analysis of the component planes suggested the presence of four fluorescence components, consistent with DOM components previously described in the literature. A remarkable strength of this methodology was that outlier samples appeared naturally integrated in the analysis. We conclude that SOM coupled with a correlation analysis procedure is a promising tool for studying large and heterogeneous EEM data sets.

Effluent particle removal by microirrigation system filters

La distribución del número y del volumen de partículas, y la eficiencia de eliminación de las partículas y los sólidos en suspensión de diferentes efluentes y sus filtrados, fueron analizadas para estudiar si los filtros más usuales en los sistemas de riego localizado eliminan las partículas que pueden obturar los goteros. En la mayoría de los efluentes y filtrados fue mínimo el número de partículas con diámetros superiores a 20 μm. Sin embargo, al analizar la distribución del volumen de las partículas, en los filtrados aparecieron partículas de dimensiones superiores a la luz de los filtros de anillas y malla, siendo el filtro de arena el que retuvo las partículas de mayor diámetro. La eficiencia de los filtros para retener partículas se debió más al tipo de efluente que al filtro. Se verificó también que la distribución del número de partículas sigue una relación de tipo potencial. Analizando el exponente β de la ley potencial, se halló que los filtros no modificaron significativamente la distribución del número de partículas de los efluentes.

Revegetació de talussos d'una explotació carbonífera mitjançant materials de rebuig

En aquest treball s'avalua la rehabilitació dels talussos d'una explotació minera carbonífera utilitzant materials de rebuig de la pròpia explotació i provinents d'activitats ramaderes (purins de porc) o urbanes (llots de depuradora), en un ambient àrid del Baix Segre. Les variables analitzades foren el tipus i recobriment vegetals, la penetromia i la salinitat del substrat, i la salinitat, els nitrats i els sediments dels efluents. Els resultats indiquen que és possible rehabilitar els runams en aquests medis, assolint recobriments vegetals fins al 50 % sense que se'n derivin efectes ambientals negatius importants. Taxes altes puntuals d'erosió poden controlar-se amb un disseny adient dels talussos. L'aplicació superficial de purí no té efectes antiencrostants. La moderada salinitat dels substrats condiciona l'establiment de vegetació halòfila.

Self-Organising Maps and Correlation Analysis as a Tool to Explore Patterns in Excitation-Emission Matrix Data Sets and to Discriminate Dissolved Organic Matter Fluorescence Components

Dissolved organic matter (DOM) is a complex mixture of organic compounds, ubiquitous in marine and freshwater systems. Fluorescence spectroscopy, by means of Excitation-Emission Matrices (EEM), has become an indispensable tool to study DOM sources, transport and fate in aquatic ecosystems. However the statistical treatment of large and heterogeneous EEM data sets still represents an important challenge for biogeochemists. Recently, Self-Organising Maps (SOM) has been proposed as a tool to explore patterns in large EEM data sets. SOM is a pattern recognition method which clusterizes and reduces the dimensionality of input EEMs without relying on any assumption about the data structure. In this paper, we show how SOM, coupled with a correlation analysis of the component planes, can be used both to explore patterns among samples, as well as to identify individual fluorescence components. We analysed a large and heterogeneous EEM data set, including samples from a river catchment collected under a range of hydrological conditions, along a 60-km downstream gradient, and under the influence of different degrees of anthropogenic impact. According to our results, chemical industry effluents appeared to have unique and distinctive spectral characteristics. On the other hand, river samples collected under flash flood conditions showed homogeneous EEM shapes. The correlation analysis of the component planes suggested the presence of four fluorescence components, consistent with DOM components previously described in the literature. A remarkable strength of this methodology was that outlier samples appeared naturally integrated in the analysis. We conclude that SOM coupled with a correlation analysis procedure is a promising tool for studying large and heterogeneous EEM data sets.

Treatment of micropollutants in municipal wastewater: study of a sequential batch biofilter

All the experimental part of this final project was done at Laboratoire de Biotechnologie Environnementale (LBE) from the École Polytechnique Fédérale de Lausanne (EPFL), Switzerland, during 6 months (November 2013- May 2014). A fungal biofilter composed of woodchips was designed in order to remove micropollutants from the effluents of waste water treatment plants. Two fungi were tested: Pleurotus ostreatus and Trametes versicolor in order to evaluate their efficiency for the removal of two micropollutants: the anti-inflammatory drug naproxen and the antibiotic sulfamethoxazole,. Although Trametes versicolor was able to degrade quickly naproxen, this fungus was not any more active after one week of operation in the filter. Pleurotus ostreatus was, on contrary, able to survive more than 3 months in the filter, showing good removal efficiencies of naproxen and sulfamethoxazole during all this period, in tap water but also in real treated municipal wastewater. Several other experiments have provided insight on the removal mechanisms of these micropollutants in the fungal biofilter (degradation and adsorption) and also allowed to model the removal trend. Fungal treatment with Pleurotus ostreatus grown on wood substrates appeared to be a promising solution to improve micropollutants removal in wastewater.

Private micro-irrigation costs using reclaimed water

The cost of reusing water in micro-irrigation at the field level has not been studied in depth although the use of effluents in agriculture is a viable alternative in areas where water is scarce or there is intense competition for its use. The aim of the present study is to analyse the private costs of water reuse in micro-irrigation in an experimental plot. This analysis is intended to provide information about the decision a farmer would make when the choice to use conventional or reclaimed water is guided by cost criteria. The components of the total costs of different combinations of four types of filters and five emitters that can be installed in micro-irrigation systems using reclaimed water have been studied with the data obtained from an experimental plot in conditions similar to those of fruit orchards. Different scenarios that compared the costs of using conventional or reclaimed water in terms of water price and nutrient content were also studied. The results show that a proper combination of filters and emitters can save up to 33% in irrigation costs. Capital costs and maintenance costs were the most variable among the different combinations. Scenario analysis showed that the greater price of reclaimed water could be compensated by high nutrient contents, which would reduce fertilizer costs

Dinámica del heleoplancton en relación a las fluctuaciones hidrológicas en aiguamolls de l’Empordà (NE de la península Ibérica). Propuesta de un método sencillo de monitorización basado en la abundancia de grupos taxonómicos

Monitoring of the 'ecological water quality' in 'Aiguamolls de l’Empordà' Natural Park was carried out between September 1996 and August 1997 . The aim of this sampling programme was to design a simple method for rapid detect changes in water quality due to human activity. These include flow regulation by the Park management, nutrient entries from effluents of a nearby wastewater treatment plant or agricultural fertilising. The proposed method is based on the analysis of the abundance of characteristic taxonomic groups of aquatic invertebrates (heleoplankton). The simplicity of the method is ensured by the use of large taxa which are easier to recognise than species. The functioning of aquatic systems has been modelled by means of correspondence analysis between samples and taxa. Results can be summerized in five environmental conditions with a regular community structure. Dominated by one taxon: cladocerans, ostracods, calanoids, cyclopoids and harpacticoids. The dynamics of both freshwater and brackish lagoons can be modelled as displacements between these five groups of environmental conditions. Nevertheless, the “calanoids situation” and the “harpacticoids situation” occur mainly in brackish lagoons, whereas the “cladocerans situation” occurs mainly in freshwater. The four principal axes of data variation have been respectively identified as nutrient turnover rate, hypertrophy, degree of mineralization of the organic matter and eutrophy. The use of these taxa has been validated by comparison with a model obtained from the species. We conclude that in a highly fluctuating system such as the one here, only persistent situations of eutrophy or hypertrophy must be equated to low 'ecological water quality'