1,720,987 research outputs found
Applicazione dei bioreattori a membrana al trattamento di reflui industriali
No full textQuaderni del Dipartimento di Ingegneria Civile ed Ambientale dell’Università di Trent
A simple method to evaluate the short-term biogas yield in anaerobic codigestion of WAS and organic wastes
No full textThe present study was aimed at setting and applying a procedure to measure the anaerobic
degradability of different organic substrates by short-term tests (2–7 days) carried out at labscale
with a low food to biomass (F/M) ratio. All tests were carried out using an acclimated
sludge taken from a pilot-plant anaerobic digester (200 L). Trials were performed with a
manometric system.
The experimental reliability of the device in measuring the anaerobic degradability was
assessed by several preliminary tests carried out using acetate and glucose as reference
substrates. The average conversion to methane was 99% for acetate and of 83% for glucose. The
results of tests in triplicate showed the high repeatability of the method with an average
coefficient of variation lower than 2%.
Then, the lab-scale procedure was applied to study the short-term anaerobic degradability of
complex organic substrates: thickened waste activated sludge, two kinds of organic fraction of
municipal solid waste (a kitchen waste and a fruit and vegetable waste collected at the wholesale
market of Florence), olive mill wastewater and freshly harvested grass. Results indicated that
organic fraction of municipal solid waste, olive mill wastewater and grass were characterized by
a much higher anaerobic degradability if compared to the thickened activated sludge, well in
agreement with literature data
Full-scale application of ozone oxidation for minimization of excess sludge production in an aerobic digester
No full textThis work regards the application of the ozonation process for reducing biological sludge production in a Wastewater Treatment Plant (WWTP). The experimental activity was carried out in the aerobic digestion unit of the full-scale WWTP of Sabaudia (LT). Three different ozone flowrates were tested: (1) 60 gO3/h; (2) 500 gO3/h; (3) 670 gO3/h. The higher ozone dosages allowed to achieve a significant decrease of the amount of sludge to be finally disposed of by the WWTP. In terms of monthly-based production, a reduction from 64 to 85% was obtained as compared to the expected amount in the absence of ozonation
Applicazione del processo Sharon®-Anammox® per la rimozione dell’azoto dal surnatante di un digestore anaerobico.
No full textExperimental determination of Anammox decay coefficient
No full textThis paper describes an experimental method used to evaluate the anaerobic ammonium oxidation (Anammox) decay coefficient by means of a batch test. The test was carried out using an experimental procedure based on manometric measurements of the dinitrogen gas that is produced by the Anammox process. The accuracy of the procedure had previously been assessed, and the method was used to determine the specific Anammox activity (SAA mg N2-N g VSS−1 d−1,) and the maximum nitrogen production rate (MNPR, NmL N2 L−1 d−1) under several different conditions. A specific batch test, which lasted for 148 days, was performed to assess the decay coefficient. The activity decrease was monitored and the estimated value of the decay coefficient was found to be 0.0048 d−1 at 35 °C, for which the corresponding half-life time of the Anammox biomass was 145 days. This value is higher than other values reported in the literature, but in accordance with the slow growth rate of the Anammox bacteria
An integrated approach in a municipal WWTP: anaerobic codigestion of sludge with organic waste and nutrient removal from supernatant
No full textCo-digestion appears to be an interesting solution to increase the biogas production of poorly performing under-loaded digesters of waste activated sludge. In the Florence WWTP anaerobic codigestion could increase nitrogen and phosphorus loading rates and thus lower the nutrient removal efficiency. In order to develop an integrated solution to upgrade the Florence WWTP, the different process units were tested in experimental plants. Anaerobic codigestion with source-collected organic solid waste in a pilot-scale bioreactor showed an increase of GPR from 0.15 to 0.45 Nl biogas/l/d with 23% of organic waste loaded. Autotrophic nitrogen removal was carried out in two lab-scale pilot plants which were fed with a real anaerobic supernatant after phosphate removal via struvite formation. The nitritation MBBR has been working for one year at steady-state conditions with a perfect nitrite/ammonium ratio equal to 1:1. Anammox biomass enrichment was performed in a suspended biomass SBR and the specific nitrogen removal rate increased from 1.7 to 58 gN/kgVSS/d in 375 days
- …
