Pilot Experimentation with Complete Mixing Anoxic Reactors to Improve Sewage Denitrification in Treatment Plants in  Small Communities

Raboni, Massimo; Torretta, Vincenzo; Viotti, Paolo; Urbini, Giordano

doi:10.3390/su6010112

Cited by 20 publications

(14 citation statements)

References 16 publications

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“…However, the efficiency of conventional processes (i.e., based on extended aeration activated sludge and trickling filters) is significantly affected by fluctuations of either sewage quality or flow rate, which are generally higher the smaller the size of the community. The effects of these fluctuations on the loss in efficiency of the treatment process has been reported in several studies (e.g., [1,2]). This problem can be overcome with the use of natural biological processes characterized by high retention times, such as lagoons and constructed wetlands.…”

Section: Introductionmentioning

confidence: 90%

UASB followed by Sub-Surface Horizontal Flow Phytodepuration for the Treatment of the Sewage Generated by a Small Rural Community

2014

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Abstract:The paper presents the results of an experimental process designed for the treatment of the sewage generated by a rural community located in the north-east of Brazil. The process consists of a preliminary mechanical treatment adopting coarse screens and grit traps, followed by a biological treatment in a UASB reactor and a sub-surface horizontal flow phytodepuration step. The use of a UASB reactor equipped with a top cover, as well as of the phytodepuration process employing a porous medium, showed to present important health advantages. In particular, there were no significant odor emissions and there was no evidence of the proliferation of insects and other disease vectors. The plant achieved the following mean abatement efficiencies: 92.9% for BOD5, 79.2% for COD and 94% for Suspended Solids. With regard to fecal indicators average efficiencies of 98.8% for fecal coliforms and 97.9% for fecal enterococci were achieved. The UASB reactor showed an important role in achieving this result. The research was also aimed at evaluating the optimal operating conditions for the UASB reactor in terms of hydraulic load and organic volumetric OPEN ACCESS Sustainability 2014, 6 6999 loading. The achieved results hence indicated that the process may be highly effective for small rural communities in tropical and sub-tropical areas.

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Section: Introductionmentioning

confidence: 90%

UASB followed by Sub-Surface Horizontal Flow Phytodepuration for the Treatment of the Sewage Generated by a Small Rural Community

2014

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“…At present, the plant serves seven municipalities with a total population equivalent of 175,000 inhabitants and a significant contribution from industrial activities (around 30% of the total inflow) [13,14]. The plant operates by means of a typical modified Ludzack-Ettinger pre-denitrification process [15][16][17][18], and some layout modifications are under study, also considering the application of new technologies in the future [19].…”

Section: Methodsmentioning

confidence: 99%

“… max,H and k s parameters have been calculated by minimizing the sum of the squares of the differences between the experimental and theoretical curves. Equation (18) has been used to calculate the maximum growth rate from experimental data [9]:…”

Section: Methodsmentioning

confidence: 99%

Assessment of Biological Kinetics in a Conventional Municipal WWTP by Means of the Oxygen Uptake Rate Method

et al. 2014

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Pollution control of surface water bodies requires stringent checks on wastewater treatment plants performances. The satisfactory operation of biological treatment, commonly performed by means of activated sludge processes, requires a number of controlling and monitoring procedures. Suitable respirometric techniques for the determination of the kinetic parameters that regulate biological processes have been implemented in order to achieve this aim. This paper describes the results of an experimental research carried out in a conventional Italian municipal wastewater treatment plant. Particularly, the research has been finalized to both evaluate the biological process for the removal of biodegradable pollutants, such as carbonaceous substrates and ammonia nitrogen, and to collect data in order to evaluate a possible plant upgrade. Heterotrophic and autotrophic biomass kinetic parameters have been examined using respirometric techniques based on oxygen uptake measurements. The research performed makes a OPEN ACCESS Sustainability 2014, 6 1834 valuable contribution toward verifying the reliability of the values proposed in the literature for some kinetic parameters, which have been commonly used for a long time.

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“…There are many applied research studies aimed at identifying new technologies for improving the existing WWTPs and their performance in terms of removal [31][32][33][34][35]; however, in this case we made simple and realistic assumptions starting from the current state of the WWTPs in the study area. We hypothesized making improvements only in large towns and cities, according to the rules listed below (RE: removal efficiency, c: collecting system): css2022 = css2001 + 30% and max(css2022) An alternative scenario (S1) provides for the extension of the sewage system coverage.…”

Section: Impacts On Water Quality and Possible Technological Responsesmentioning

confidence: 99%

The Sustainable Use of Water Resources: A Technical Support for Planning. A Case Study

Torretta

2014

Sustainability

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The paper presents both the structure and application of a Decision Support System (DSS) for an important river in Brazil-along with the sustainable management of its watershed. This DSS assesses both surface-water quality and riverine microhabitats in terms of future scenarios, taking into account regulation limits and appropriate quality indexes. Our future scenarios consider: (a) population and climate change trends; (b) upgrade of sewage systems and wastewater treatment plants; and (c) withdrawal management from rivers and reservoirs. We use some main types of interrelated models, which can simulate different aspects of the responses of a basin, with respect to different modes of use of the water resource. In particular, the surface-water quality models simulate total phosphorus, BOD, dissolved oxygen concentration and thermo-tolerant coliform bacteria pollution. The riverine microhabitat models apply habitat suitability indexes of autochthonous fish species considering water depth, velocity, bottom substrate and dissolved oxygen. Both models are based on hydrologic and hydraulic models results and both were calibrated using discharge and water quality measurements collected over a 1.5-year monitoring period. Our pre-and post-processing are based on common spreadsheets and the output data are spatially analyzed using GIS software. Examples are also shown of how the DSS can contribute to developing a sustainable use of the basin resources, including a reservoir used to supply drinking water to the capital city (Salvador da Bahia).

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Pilot Experimentation with Complete Mixing Anoxic Reactors to Improve Sewage Denitrification in Treatment Plants in Small Communities

Cited by 20 publications

References 16 publications

UASB followed by Sub-Surface Horizontal Flow Phytodepuration for the Treatment of the Sewage Generated by a Small Rural Community

UASB followed by Sub-Surface Horizontal Flow Phytodepuration for the Treatment of the Sewage Generated by a Small Rural Community

Assessment of Biological Kinetics in a Conventional Municipal WWTP by Means of the Oxygen Uptake Rate Method

The Sustainable Use of Water Resources: A Technical Support for Planning. A Case Study

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