Biomedical subjects

G Andreottola

Publications and source records attributed to G Andreottola.

9 recordsLinked to original sources

PubMed2005

Treatment of winery wastewater in a full-scale fixed bed biofilm reactor.

The treatment of winery wastewater was performed at full-scale applying a two-stage fixed bed biofilm reactor (FBBR) system for the discharge in the sewerage. The results of the first year of operation at the full-scale plant are presented. Values of removed organic loads and effluent concentrations were interpreted on the basis of the COD fractionation of influent wastewater assessed through respirometric tests. The average removal efficiency of total COD was 91 %. It was not possible to reach an higher efficiency because of the unbiodegradable soluble fraction of COD (about 10% of total COD on average during the whole year), that cannot be removed by biological process or settling. Due to the high empty space offered by the plastic carriers, FBBRs did not require backwashing during the seasonal operationing period of the plant (September-March). In comparison with other treatment systems the FBBR configuration allows one to ensure a simple management, to obtain high efficiency also in the case of higher fluctuations of flow and loads and to guarantee a good settleability of the sludge, without bulking problems.

Biofilms↗

PubMed2003

Upgrading of a small overloaded activated sludge plant using a MBBR system.

The aim of this research was the application of a biofilm system for the upgrading of a full-scale overloaded activated sludge MWWTP using the MBBR (Moving Bed Biofilm Reactor) technology. The choice of this fixed biomass system appeared appropriate because it offers several advantages including good potential in nitrification process, easiness of management and above all, the possibility to use the existing tank with very few modifications. MBBR system counts only few full-scale plants in Italy at the moment, thus a pilot-scale experimentation was preliminarily carried out. The acquired parameters were used for the fullscale MWWTP upgrading. The upgrading of the activated sludge reactor in the MBBR system has given (1) a relevant increase in the flowrate treated up to 60%; (2) a good efficiency in organic carbon removal and nitrification, equal to 88% and 90% respectively, with HRTs of 5.5-7 h; (3) the overcoming of the hydraulic overload of the secondary settler, applying a lamellar settler. It was observed a good correlation between the results obtained at pilot-scale and those observed in the full-scale plant.

Biofilms↗

PubMed2003

Treatment of mountain refuge wastewater by fixed and moving bed biofilm systems.

Tourists visiting mountain refuges in the Alps have increased significantly in the last decade and the number of refuges and huts at high altitude too. In this research the results of an intensive monitoring of a wastewater treatment plant (WWTP) for a tourist mountain refuge located at 2,981 m a.s.l. are described. Two biofilm reactors were adopted: (a) a Moving Bed Biofilm Reactor (MBBR); (b) a submerged Fixed Bed Biofilm Reactor (FBBR). The aims of this research were: (i) the evaluation of the main parameters characterising the processes and involved in the design of the wastewater plants, in order to compare advantages and disadvantages of the two tested alternatives; (ii) the acquisition of an adequate knowledge of the problems connected with the wastewater treatment in alpine refuges. The main results have been: (i) a quick start-up of the biological reactors obtainable thanks to a pre-colonization before the transportation of the plastic carriers to the refuge at the beginning of the tourist season; (ii) low volume and area requirement; (iii) significantly higher removal efficiency compared to other fixed biomass systems, such as trickling filters, but the energy consumption is higher.

Altitude↗

PubMed2002

Dairy wastewater treatment in a moving bed biofilm reactor.

Dairy raw wastewater is characterised by high concentrations and fluctuations of organic matter and nutrient loads related to the discontinuity in the cheese production cycle and machinery washing. The applicability of a Moving Bed Biofilm Reactor (MBBR) filled with FLOCOR-RMP plastic media to the treatment of dairy wastewater was evaluated in a pilot-plant. COD fractionation of influent wastewater, MBBR performance on COD and nutrient removal were investigated. A removal efficiency of total COD over 80% was obtained with an applied load up to 52.7 gCOD m-2 d-1 (corresponding to 5 kgCOD m-3d-1). The COD removal kinetics for the MBBR system was assessed. The order of the kinetics resulted very close to half-order in the case of a biofilm partially penetrated by the substrate. The nitrogen removal efficiency varied widely between 13.3 and 96.2% due to the bacterial synthesis requirement. The application of a MBBR system to dairy wastewater treatment may be appropriate when upgrading overloaded activated sludge plants or in order to minimise reactor volumes in a pre-treatment.

Animals↗

PubMed2002

Treatment of winery wastewater in a sequencing batch biofilm reactor.

Pilot-scale experiments were carried out applying the SBBR process (Sequencing Batch Biofilm Reactor) for the treatment of winery wastewater. The aim was the evaluation of the SBBR performance and the development of a control strategy based on dissolved oxygen (DO) for the optimisation of the SBBR treatment cycle and the minimisation of the energy supply. The results of the experimentation have confirmed the applicability of the SBBR process pointing out high COD removal efficiencies between 86% and 99%, with applied loads up to 29 gCOD m-2d-1, corresponding to 8.8 kgCOD m-3d-1. The on-line monitoring of DO concentration appeared as a good indicator of the progress in the COD biodegradation. The control strategy for the ending of the SBBR cycles was based on the time derivative of the DO concentration. The optimised control strategy makes it possible to obtain a steady quality of the effluent wastewater with an average daily applied load of 6.3 kgCOD m-3d-1 rather than 3.5 kgCOD m-3d-1 for the non-optimised SBBR cycle. The possibility of optimising the SBBR cycle through a simple control of the DO in the mixed liquor could be an interesting solution for the biological pre-treatment of winery wastewater to be discharged into sewerage or as a single-stage of a combined treatment plant for the discharge into surface water.

Biofilms↗

PubMed2002

Biomass active fraction evaluated by a direct method and respirometric techniques.

The knowledge of the active biomass amount and its characterisation is of primary importance for the management and for the design of wastewater treatment plants on the basis of the recently developed models. OUR curves obtained in aerobic exponential growth tests are proposed by several authors as an indirect method to estimate the active fraction. The aim of this work is the application of a direct method to measure the viable biomass based on flow cytometry techniques and the comparison with the active fraction obtained from respirometric tests. To assess the viable fraction of a biomass expressed in terms of COD concentration it is necessary to estimate the biovolume of viable bacteria and to know the specific carbon content per cell. For the investigated activated sludge samples, the bacterial biomass measured by FCM was 588 mgCOD L(-1) on average in a two-months period. This value of active fraction corresponds to 14% of particulate COD. Active biomass values measured with the respirometric approach were consistent but generally higher than those obtained by FCM.

Biomass↗

PubMed2002

A comparison among different methods for evaluating the biomass activity in activated sludge systems: preliminary results.

In order to improve activated sludge plant operation (achieving higher efficiency and cost savings) beside influent and effluent characteristics and working parameters (e.g. dissolved oxygen, total and volatile suspended solids, pH, recirculation flow rate, etc.), the biomass activity should be monitored, the bacteria being responsible for the pollutant degradation. Since conventional cultivation based methods are inadequate to quantify environmental microorganisms (due to scarce number of cultivable microorganisms and time-consuming procedures) several "non-conventional" techniques were applied in this study, in order to compare the obtainable information and their routine feasibility. Different measurements (VSS concentration, Oxygen Uptake Rate, microbial counts by cultural and biomolecular methods--MPN-PCR, ATP content, dehydrogenase activity, microbial cell viability and enzymatic activity) were carried out on mixed liquor samples, taken from a municipal activated sludge plant (440,000 p. e.). The preliminary results of the research are presented in this paper.

Adenosine Triphosphate↗

PubMed2001

On-line control of a SBR system for nitrogen removal from industrial wastewater.

In this study, laboratory-scale experiments were conducted applying the SBR activated sludge process to a wastewater from a wood factory operating on plywood production. Due to the fact that the wastewater is characterised with a high concentration of ammonia, the aim was to evaluate the nitrogen removal process with SBR system operating with a on-line control of ORP, pH and DO. The complete ammonia removal corresponded exactly to the "Ammonia Valley" in the pH versus time graphic. The ammonia removal efficiency in SBR was 99% at 20 degrees C. The denitrification reaction was completed when in the ORP versus time graphic appeared the "Nitrate Knee". From the experimental results the optimisation of the SBR cycle allowed the doubling of the applied load with respect to a not optimised cycle (performed in the same volume reactor), without a decrease in the removal efficiency. Moreover, the possibility of stopping the aeration just after the appearance of the Ammonia Valley allows an energy saving. The easy operation and the low cost make the SBR system an interesting option for the biological pre-treatment of plywood industry to be discharged into surface water.

Aerobiosis↗

PubMed2001

Experimental validation of a single-OUR method for wastewater RBCOD characterisation.

Wastewater characterisation is of primary importance for the correct design and management of a treatment plant. The aim of this work was the evaluation of a new rapid and easy to use respirometric technique for the characterisation of readily biodegradable COD (RBCOD). When the necessary calibration curve is obtained, the RBCOD assessment procedure needs less than 30 minutes. On the contrary, conventional techniques require some hours. The first step consists in calculating a calibration curve in order to point out the correlation between oxygen consumed and known amount of added Sodium Acetate. To a well aerated biomass (in order to remove residual readily biodegradable substrate) a known amount of Sodium Acetate is added and the related OUR is measured. The oxygen consumed (delta DO) is related to the added COD (as Sodium Acetate). Therefore, the RBCOD concentration in wastewater samples can be obtained according to the following steps: (1) measure delta DO; (2) multiply delta DO by the Volume of aerated mixed liquor used in the test; (3) from the calibration curve, calculate the readily biodegradable COD equivalent to Acetate; (4) estimate RBCOD concentration multiplying the wastewater sample volume tested in the reactor. Some advantages of this technique are described in the paper.

Algorithms↗