1,721,155 research outputs found
FISH PROCESSING WASTEWATER. PRODUCTION OF READILY BIODEGRADABLE COD TO IMPROVE NITROGEN REMOVAL.
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INQUINAMENTO DA SOLVENTI ORGANICI IN AMBIENTI DI LAVORO: IMPORTANZA DI UNA CORRETTA VENTILAZIONE.
No full textAlternate cycles process for municipal wwtp upgrading: ready for widespread application?
No full textThe interest in the biological alternating anoxic/oxic reactors to upgrade existing wastewater treatment plants
has been recently renewed, thanks to the use of reliable automatic control systems. To discuss the treatment
capabilities of the alternating systems, with particular relation to the municipal WWTPs’ upgrading, this
study exploits the experience gained in this field through numerous years of R&D. At first a pilot plant study
and then a full scale alternating plant were used to supply experimental data that support the final schematic
of methodology. The pilot experimentation was based in the real loading conditions of the italian municipal
WWTPs. Real municipal sewage was used to feed the plant in six steady-state periods, applying nitrogen
loading rates ranging from 0.03 to 0.1 kg N m-3 d-1. Major problems with the nitrogen removal performances
occurred in the case of overaeration of the activated sludge tank, corresponding to influent low-loaded
wastewater. The experimental durations per day of the anoxic and oxic phases were in good agreement with
a simplified mathematical model, which was validated by full scale data and was finally considered useful for
the upgrading design. The maximum treatment capacity of the process in terms of nitrogen loading rates was
estimated in the range 0.10-0.16 kg N m-3 d-1 according to the different rates for biological nitrification
and denitrification, which influence the oxic and anoxic durations per day. Moreover, the reliability of the
control device used for the experimentation was proved through the statistic analyses of the performed cycles,
which were in agreement with the actual nitrogen removal performances. Finally, the schematic of methodology
shows how easy and consolidated the upgrading of existing wastewater treatment plants by the alternate
cycles process could be
La cristallizzazione della struvite come metodo per la rimozione ed il recupero del fosforo da surnatanti anaerobici
No full textAuto-nucleation and crystal growth of struvite in a demonstrative fluidized bed reactor (FBR)
No full textApplication of food waste disposers and alternate cycles process in small decentralised towns: a case study
No full textThe use of food waste disposers (FWDs) can be an interesting option to integrate the management of municipal wastewaters and household organic waste in small towns and decentralized areas. This strategy can be even more environmentally friendly if a suitable treatment process of the resulting sewage is performed in order to control nutrients emission. However, still nowadays, part of the scientific and technical community considers the application of this technology a possible source of problems. In this study, the FWDs were applied, with a market penetration factor of 67%, in a mountain village of 250 inhabitants. Further, the existing wastewater treatment plant (WWTP) was upgraded by applying an automatically controlled alternate cycles process for the management of nutrients removal. With specific reference to the observed results, the impact of the ground food waste on the sewerage system did not show particular solids sedimentation or significant hydraulic overflows. Further, the WWTP was able to face the overloads of 11, 55 and 2 g per capita per day of TSS, COD and TN, respectively. Then, the increase of the readily biodegradable COD (rbCOD/COD from 0.20 to 0.25) and the favourable COD/TN ratio (from 9.9 to 12) led to a specific denitrification rate of some 0.06 kg NO3-N/(kg MLVSS day). Therefore, not only COD removal, but also the total nitrogen removal increased: the denitrification efficiency reached 85%. That led to a better exploitation of the nitrogen-bound oxygen and a consequent reduction of energy requirements of 39%. The final economic evaluation showed the benefits of the application of this technology with a pay back time of 4–5 years.<br/
Best operative practices for the management of full scale biological reactor for non hazardous landfill leachate treatment
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