Search results for "sanit"
showing 10 items of 944 documents
Insights on mechanisms of excess sludge minimization in an oxic-settling-anaerobic process under different operating conditions and plant configurati…
2022
In the present research, insights about the mechanisms of excess sludge minimization occurring in an oxic-settling-anaerobic (OSA) were provided. The investigation involved two systems operating in parallel. In particular, a conventional activated sludge (CAS) system as control and a system implementing the OSA process both having a pre-denitrification scheme were considered. Five periods (P1-P5) were studied, during which several operating conditions and configurations were tested. Specifically, the hydraulic retention time (HRT) in the anaerobic reactor of the OSA system (P1 8 h, P2-P3 12 h, P4 8 h, P5 12 h) and the return sludge from the anaerobic to the anoxic (scheme A) (P1-P2) or aero…
Comparison between ozonation and the OSA process: analysis of excess sludge reduction and biomass activity in two different pilot plants
2012
The excess biomass produced during biological treatment of municipal wastewater represents a major issue worldwide, as its disposal implies environmental, economic and social impacts. Therefore, there has been a growing interest in developing technologies to reduce sludge production. The main proposed strategies can be categorized according to the place inside the wastewater treatment plant (WWTP) where the reduction takes place. In particular, sludge minimization can be achieved in the wastewater line as well as in the sludge line. This paper presents the results of two pilot scale systems, to evaluate their feasibility for sludge reduction and to understand their effect on biomass activit…
Stormwater infiltration trenches: a conceptual modelling approach.
2009
In recent years, limitations linked to traditional urban drainage schemes have been pointed out and new approaches are developing introducing more natural methods for retaining and/or disposing of stormwater. These mitigation measures are generally called Best Management Practices or Sustainable Urban Drainage System and they include practices such as infiltration and storage tanks in order to reduce the peak flow and retain part of the polluting components. The introduction of such practices in urban drainage systems entails an upgrade of existing modelling frameworks in order to evaluate their efficiency in mitigating the impact of urban drainage systems on receiving water bodies. While s…
Toward a New Plant-Wide Experimental and Modeling Approach for Reduction of Greenhouse Gas Emission from Wastewater Treatment Plants
2019
Mechanisms causing greenhouse gas (GHG) emission in wastewater treatment plants are of great interest among researchers, encouraging the development of new methods for wastewater management. Wastewater treatment plants (WWTPs) emit three major greenhouse gases during the treatment processes: CO2, CH4, and N2O. Additional amounts of CO2 and CH4 are produced during energy consumption, which can be considered an indirect source of GHGs. Recently, several efforts have been undertaken to assess GHGs from WWTPs, with particular attention paid to the N2O assessment due to its high warming potential (300 times stronger than CO2). This study proposes an integrated model platform for WWTP simulation,…
The role of EPS in fouling and foaming phenomena for a membrane bioreactor
2013
In contraposition to conventional activated sludge processes, the foaming phenomenon in membrane bioreactor (MBR) is still in its infancy. On the other hand, although several studies have been carried out for better understanding the fouling phenomenon in MBR there are still some gaps in the up-to-date knowledge. The extracellular polymeric substances (EPSs) may have a primary role in fouling and foaming phenomena which in turn can be crucial for MBRs. The aim of this study is to detect a possible relationship that EPSs may have with fouling and foaming in an MBR for wastewater treatment. Foaming phenomenon is monitored by performing specific foam-tests: Foam Power, Scum Index, Foam Rating …
Editorial: Sustainable wastewater treatment and resource recovery
2020
Water
Sewage sludge acidogenic fermentation for organic resource recovery towards carbon neutrality: an experimental survey testing the headspace influence
2022
Volatile fatty acids (VFAs) produced by acidogenic digestion of sewage sludge are very interesting bio-products which can contribute to carbon neutrality of wastewater treatment plants. Studies on the production of VFAs from sewage sludge from fermenters with membrane are limited. In view of above, VFAs from a fermenter pilot plant equipped with a membrane bioreactor and fed with real sewage sludge has been monitored. The effect of headspace volume (HdV) on VFA production was studied for the first time to elucidate the optimal operation conditions. Specifically, three fermenter HdV values (namely, 20, 40 and 60% of the total volume) have been investigated. Results revealed that the HdV of 2…
Uncertainty in urban flood damage assessment due to urban drainage modelling and depth-damage curve estimation
2010
Due to the increased occurrence of flooding events in urban areas, many procedures for flood damage quantification have been defined in recent decades. The lack of large databases in most cases is overcome by combining the output of urban drainage models and damage curves linking flooding to expected damage. The application of advanced hydraulic models as diagnostic, design and decision-making support tools has become a standard practice in hydraulic research and application. Flooding damage functions are usually evaluated by a priori estimation of potential damage (based on the value of exposed goods) or by interpolating real damage data (recorded during historical flooding events). Hydrau…
Hybrid activated sludge/biofilm process for the treatment of municipal wastewater in a cold climate region: a case study.
2011
A hybrid activated sludge/biofilm process was investigated for wastewater treatment in a cold climate region. This process, which contains both suspended biomass and biofilm, usually referred as IFAS process, is created by introducing plastic elements as biofilm carrier media into a conventional activated sludge reactor. In the present study, a hybrid process, composed of an activated sludge and a moving bed biofilm reactor was used. The aim of this paper has been to investigate the performances of a hybrid process, and in particular to gain insight the nitrification process, when operated at relatively low MLSS SRT and low temperatures. The results of a pilot-scale study carried out at the…
Technical assessment and evaluation of environmental models and software: Letter to the Editor
2011
International audience; This letter details the collective views of a number of independent researchers on the technical assessment and evaluation of environmental models and software. The purpose is to stimulate debate and initiate action that leads to an improved quality of model development and evaluation, so increasing the capacity for models to have positive outcomes from their use. As such, we emphasize the relationship between the model evaluation process and credibility with stakeholders (including funding agencies) with a view to ensure continued support for modelling efforts. Many journals, including EM&S, publish the results of environmental modelling studies and must judge the w…