OLIVE MILL WASTE MANAGEMENT-THE CASE OF MESSENIA AREA

Η ελαιουργία είναι η κυριότερη αγροτοβιομηχανική δραστηριότητα στο νομό Μεσσηνίας και προκαλεί διάφορα περιβαλλοντικά προβλήματα. Τα περισσότερα ελαιοτριβεία είναι μικρά ως μεσαία που αδυνατούν να καταβάλουν το κόστος επεξεργασίας των αποβλήτων, καταλήγοντας στην ανεξέλεγκτη διάθεση σε φυσικούς αποδέκτες. Η νέα τεχνολογία των διφασικών ελαιοτριβείων δεν παράγει σημαντική ποσότητα υγρών αποβλήτων και λύνει εν μέρει μόνο το πρόβλημα καθώς είναι ακριβή για τα μικρά ελαιοτριβεία. Το μεγάλο κόστος των συμβατικών μεθόδων επεξεργασίας και η χωρική διασπορά των ελαιοτριβείων καθιστά αδύνατη την επεξεργασία σε κεντρικές μονάδες συμβατικής τεχνολογίας. Διερευνώνται εναλλακτικοί τρόποι διαχείρισης των αποβλήτων με μεθόδους επεξεργασίας χαμηλού κόστους και προσαρμοσμένοι στα χαρακτηριστικά του ελαιουργικού κλάδου της Μεσσηνίας. Olive oil industry is the main agro-industrial activity in the area of Messenia, causing various environmental problems. Most olive mills are small to medium sized and unable to pay the costs for the treatment of their wastewater, so, they end up in the uncontrolled disposal or their wastewater in natural sites. The new two-phase technology of olive mills does not produce big amounts of wastewater and it only partially solves the problem as it is too expensive for small sized olive mills. The implementation of big central treatment plants is practically impossible because of the high costs of the treatment methods and the high spatial dispersion of olive mills. Alternative ways for the management of olive mill wastewater are investigated, adopting low cost treatment methods and adapted to the characteristics of olive oil industry in the area of Messenia

Ultrasound enhancement of near-neutral photo-Fenton for effective E. coli inactivation in wastewater

In this study, we attempt for the first time to couple sonication and photo-Fenton for bacterial inactivation of secondary treated effluent. Synthetic wastewater was subjected to sequential high-frequency/low power sonication, followed by mild photo-Fenton treatment, under a solar simulator. It was followed by the assessment of the contribution of each component of the process (Fenton, US, hv) towards the removal rate and the long-term survival; sunlight greatly improved the treatment efficiency, with the coupled process being the only one to yield total inactivation within the 4-h period of treatment. The short-term beneficial disinfecting action of US and its detrimental effect on bacterial survival in long term, as well as the impact of light addition were also revealed. Finally, an investigation on the operational parameters of the process was performed, to investigate possible improvement and/or limitations of the coupled treatment; 3 levels of each parameter involved (hydraulic, environmental, US and Fenton) were tested. Only H2O2 increased improved the process significantly, but the action mode of the joint process indicated potential cost-effective solutions towards the implementation of this method. (C) 2014 Elsevier B.V. All rights reserved.Preprin

LEACHING TESTS AND ECOTOXICITY OF SEWAGE SLUDGE SAMPLES

Δείγματα ιλύος από Εγκαταστάσεις Επεξεργασίας Λυμάτων (ΕΕΛ), με διαφορετική περιεκτικότητα σε οργανική ύλη, υποβλήθηκαν σε φυσικοχημικές αναλύσεις, δοκιμές έκπλυσης και οικοτοξικολογικές δοκιμές με σκοπό τη διερεύνηση των περιβαλλοντικών επιπτώσεων από τη διάθεση της ιλύος στο έδαφος. Πραγματοποιήθηκαν πειράματα φυτοτοξικότητας σε τρεις ανώτερους φυτικούς οργανισμούς, (Sorghum saccharatum, Lepidium sativum and Sinapis alba), σε αναλογίες μίγματος ιλύος προς έδαφος (2.5-25%). Επιπλέον, τα δείγματα ιλύος  υποβλήθηκαν σε δοκιμές έκπλυσης, σύμφωνα με τη δοκιμή έκπλυσης NEN 7341 (δύο στάδια έκπλυσης αθροιστικής αναλογίας υγρού/στερεού, L/S= 100 L/kg) και τη δοκιμή ανοδικής διήθησης EN 14405, σε αθροιστικές αναλογίες L/S= 0.1, 0.2, 0.5, 1.0, 2.0, 5.0, 10 και 20 L/kg. Τα οικοτοξικολογικά χαρακτηριστικά των εκπλυμάτων, προσδιορίστηκαν με βάση την επίδρασή τους στη φωταύγεια του βακτηρίου V.  fischeri και στην κινητικότητα του καρκινοειδούς D. magna. Τα δείγματα παρουσίασαν φυτοτοξική δράση σε αναλογίες μίγματος ιλύος/εδάφους μεγαλύτερες από 5%, ενώ τα υγρά έκπλυσης παρουσίασαν σε ορισμένες περιπτώσεις υψηλές τιμές οικοτοξικότητας, έως και 100%.Sewage sludge samples of different organic matter content were subjected to physicochemical analyses, leaching tests and ecotoxicity tests, in order to evaluate the environmental impact of their application on land. Phytotoxicity tests of soil samples were performed against three higher plants (Sorghum saccharatum, Lepidiumsativum and Sinapis alba), at various mixture ratios of dried sludge/soil (2.5- 25%). Furthermore, the dried sludge samples were subjected to the availability leaching test NEN 7341 (two stage leaching test to a cumulative liquid/solid ratio, L/S= 100 L/kg) and to the up-flow percolation test EN 14405 for cumulative ratios L/S= 0.1, 0.2, 0.5, 1, 2, 5, 10 and 20 L/kg. The eco-toxicological characteristics of the leachates were determined by measuring their effects to the luminescence of the bacterium V. fischeri and to the mobility of the crustacean D. magna. Phytotoxic effects were observed for sludge/soil ratios higher than 5%, while the leachates exhibited in some cases a high ecotoxic effect, up to 100%

Elucidating bacterial regrowth: Effect of disinfection conditions in dark storage of solar treated secondary effluent

In this study, we systematically investigate solar disinfection of synthetic secondary wastewater, with the effort to decrypt the effects disinfection conditions have on post-irradiation bacterial regrowth in the dark. A full factorial design of 240 experiments was employed to investigate the effects of (i) exposure time (1, 2, 3 and 4 h), (ii) treatment temperature (20, 30, 40, 50 and 60 °C), (iii) initial bacterial concentration (10 3, 104, 105 and 106 CFU/mL) and (iv) sunlight intensity (0, 800 and 1200 W/m2) on Escherichia coli survival for a subsequent 48-h dark control period. The decisive implications treatment temperature inflicted in regrowth were monitored and interpreted within two temperature ranges, from 20 to 40 °C and 40 to 60 °C. In dark tests, bacterial populations presented initial moderate growths at 20-40 °C range, followed by intense regrowth. At 40-60 °C range, acute thermal inactivation without long-term regrowth predominated at 50 °C and was total at 60 °C, within the 4-h treatment period. Introduction of light resulted in higher removal rates or permanent inactivation for 800 and/or 1200 W/m 2, respectively. No post-treatment regrowth in the dark was observed after 24 and 48 h, in completely inactivated samples, and its demonstration, when observed, was well correlated to the bacterial numbers at the end of the disinfection period. Statistical observations on the transferred bacterial populations from day to day are also discussed in this paper

Solar disinfection modeling and post-irradiation response of Escherichia coil in wastewater

In this work, an intensive assessment of solar disinfection of secondary wastewater was elaborated in controlled laboratory conditions. Batch tests of Escherichia coil-spiked synthetic secondary effluent, at nine different constant intensity levels, were followed by a 48-h dark storage. Solar disinfection was monitored in half-hourly intervals demonstrating distinct phases of lag followed by sharp inactivation. The results were fit to a shoulder log-linear and a Weibull distribution model. The solar-driven inactivation, the latency period and the effective disinfection time (for 4-log reduction) were correlated properly with the applied irradiance, resulting in a common, standardized dose for all intensities. Evolution of bacterial response in the dark was monitored for 48 h, and was in each case characterized as growth or decay. Also, the energy threshold, which was able to shift post-irradiation behavior from growth to decay, was analytically studied. In all intensity levels, this standard was approximately constant, as an effective bacteriostatic dose (EBD). Finally, similar dose-related disinfection and regrowth effects were observed, suggesting compliance with the reciprocity law, with minor deviations. (C) 2015 Elsevier B.V. All rights reserved

Monitoring the post-irradiation E-coli survival patterns in environmental water matrices: implications in handling solar disinfected wastewater

In this study, simulated solar disinfection of secondary effluent was followed by dark storage at different temperatures or different receiving water matrices. Escherichia coil illumination was followed by 3-day monitoring of the bacterial population and its adaptation in different temperature conditions in the dark. The subsequent survival was linked to the dose received during exposure to light, and results were obtained on the environmentally induced prolongation of survival, maintenance of population or excessive growth, at 4 degrees C, 20 degrees C and 37 degrees C, respectively. An additional set of experiments at 20 degrees C was subjected to dilution in E. coli-free synthetic wastewater, water from Lake Leman, (synthetic) seawater and Mili-Q water. Post-irradiation monitoring was also conducted, studying 50%, 10% and 1% dilution rates, and the results were attributed to the two parameters of dilution medium and dilution ratio. However, different responses were found based on the acquired dose during pre-treatment. This indicates the importance of the illumination prior to storage, and the preference of bacteria in some matrices over the others. Survival was linked to initial population, dose, dilution and medium; shorter illumination times are to be considered according to the receiving water matrix. (C) 2014 Elsevier B.V. All rights reserved.Postprint (published version

Enhanced Mesophilic Anaerobic Digestion of Primary Sewage Sludge

Processing of the produced primary and secondary sludge during sewage treatment is demanding and requires considerable resources. Most common practices suggest the cotreatment of primary and secondary sludge starting with thickening and anaerobic digestion. The aim of this study is to investigate the anaerobic digestion of the primary sludge only and estimate its impact on sludge treatment and energy recovery. Within this context, the performance of the anaerobic digestion of primary sludge is explored and focused on practices to further enhance the methane production by using additives, e.g., a cationic polyelectrolyte and attapulgite. The results showed that the overall yield in methane production during anaerobic digestion of primary sludge alone was higher than that obtained by the anaerobic digestion of mixed primary and secondary sludge (up to 40%), while the addition of both organic polyelectrolyte and attapulgite enhanced further the production of methane (up to 170%). Attapulgite increased the hydrolysis rate of biosolids and produced relatively stabilized digestate, though of lower dewaterability. Moreover, the results suggest that single digestion of primary sludge may accomplish higher methane production capacities at lower digestors’ volume increasing their overall efficiency and productivity, while the produced digestates are of adequate quality for further utilization mainly in agricultural or energy sectors

A C"1 triangular interpolant suitable for scattered data interpolation

SIGLEAvailable from British Library Document Supply Centre- DSC:3394.2725(DU-DMCS-CS--90/03) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Elucidating bacterial regrowth: effect of disinfection conditions in dark storage of solar treated secondary effluent

In this study, we systematically investigate solar disinfection of synthetic secondary wastewater, with the effort to decrypt the effects disinfection conditions have on post-irradiation bacterial regrowth in the dark. A full factorial design of 240 experiments was employed to investigate the effects of (i) exposure time (1, 2,3 and 4h), (ii) treatment temperature (20, 30, 40, 50 and 60 degrees C), (iii) initial bacterial concentration (10(3), 10(4), 10(5) and 10(6) CFU/mL) and (iv) sunlight intensity (0, 800 and 1200 W/m(2)) on Escherichia coli survival for a subsequent 48-h dark control period. The decisive implications treatment temperature inflicted in regrowth were monitored and interpreted within two temperature ranges, from 20 to 40 degrees C and 40 to 60 degrees C. In dark tests, bacterial populations presented initial moderate growths at 20-40 degrees C range, followed by intense regrowth. At 40-60 degrees C range, acute thermal inactivation without long-term regrowth predominated at 50 degrees C and was total at 60 degrees C, within the 4-h treatment period. Introduction of light resulted in higher removal rates or permanent inactivation for 800 and/or 1200 W/m(2), respectively. No post-treatment regrowth in the dark was observed after 24 and 48 h, in completely inactivated samples, and its demonstration, when observed, was well correlated to the bacterial numbers at the end of the disinfection period. Statistical observations on the transferred bacterial populations from day to day are also discussed in this paper. (C) 2014 Elsevier B.V. All rights reserved