Tiziano Zarra

Wastewater treatment by membrane ultrafiltration enhanced with ultrasound: effect of membrane flux and ultrasonic frequency

HighlightsUltrasonic enhanced membrane ultrafiltration at two fluxes and two US frequencies.Enhancement of the treatment performance at the lowest US frequency of 35 kHz.US are more effective in fouling rate reduction at higher membrane flux (150 L/m2 h).Higher OM and turbidity removals were obtained at 130 kHz. ABSTRACT Membrane ultrafiltration is increasingly applied for wastewater treatment and reuse, even though membrane fouling still represents one of the main drawbacks of this technology. In the last years, innovative strategies for membrane fouling control have been developed, such as the combination of membrane processes with ultrasound (US). In present work, the application of membrane ultrafiltration and its combination with US were studied, evaluating the influence on the performance of the treatment and membrane fouling formation of two membrane fluxes, 75 and 150 L/m2 h, along with two US frequencies, 35 and 150 kHz. The results observed showed that the combination of membrane ultrafiltration with US, respect to the filtration process alone, reduced membrane fouling rates to a greater extent at the higher membrane flux and lower US frequency applied, reaching a reduction of 57.33% at 150 L/m2 h and 35 kHz. Furthermore, higher organic matter and turbidity removals were observed at higher frequency (130 kHz). The results obtained highlights the applicability of this combined process for the upgrading of membrane ultrafiltration and as an alternative option to conventional tertiary wastewater treatments.

Control of odour emission in wastewater treatment plants by direct and undirected measurement of odour emission capacity.

Odour emissions from wastewater treatment plants (WWTPs) are considered to be the main causes of disturbance noticed by the exposed population and have relevant impacts on both tourism economy and land costs. Odour impact from WWTPs is generated by primary and secondary odour emissions. Primary odour emissions are related especially to the wastewater type and variability discharged into the sewer and directed to the WWTP, and to the wastewater collection and sewage system. Secondary odours are related to the treatment units of the plant. Several studies describe the key role of primary odour emissions and how they are strongly related to odour impacts of WWTPs. In this way, a opportune characterization of the emission capacity of primary odour could be an effective way to control odour emission in the WWTPs. In this study the odour emission capacity (OEC) of different domestic sewers was described and investigated; a correlation between the OEC and the main physical-chemical parameters of wastewater quality was also carried out. Results of this study identify the optimum conditions for sampling and measuring OEC in wastewaters and define its dependence by wastewater quality. These results can contribute to setting the standards for the maximum odourant content of wastewater that are discharged into the publicly owned sewage system.

Performance Study of E-Nose Measurement Chamber for Environmental Odour Monitoring

Offensive odours from industrial and sanitary environmental engineering plants can cause problems, such as sleep disorders, migraine and loss of appetite, also considering that they address the quality of life. Odour emission characterization is currently discussed in international literature as to determine its most feasible implementation. A method for continuous odour monitoring is based on the use of electronic noses. Electronic nose is an instrument which comprises an array of electronic chemical sensors with partial specificity and an appropriate pattern recognition system, capable of recognizing simple or complex odours. Aim of this work is to numerically analyze the performance of a sensor chamber in order to improve sensor response signals in terms of stability, reproducibility and response time. Comparative results are based on the location of four different diffusers. The numerical analysis was performed by a computational fluid dynamic (CFD) software in order to guarantee that all sensors are exposed to the same chemical sample under the same experimental conditions for the same time, reducing the presence of stagnant or recirculating regions.

An alternative approach of the e-nose training phase in odour impact assessment

Odour emissions are causing serious nuisance for the population, especially in the surrounding of waste water treatment plants (WWTP) and solid waste treatment plants. Extended exposure to odours generate undesirable reactions ranging from emotional stresses such as unease, discomfort, headaches, or depression to physical symptoms. Odour emission characterization is currently discussed in international literature for opportune implementation. Measurement of emissions can be achieved using different methods (analytical, sensorial and/or senso-instrumental) that have different advantages and problems. Among these techniques, there is a growing interest towards the environmental applications of electronic noses. Electronic nose is the only technique that allows continuous monitoring of odours. However, at present there are several limitations affecting the application of electronic nose in the environmental sector. The study investigates the electronic nose potentialities in the environmental sector. Scope of this research activity is to investigate an alternative method to build training data set necessary to distinguish different odour sources generated by solid waste treatment facilities through electronic nose application. The proposed methodology is based on the straightforward application of the electronic nose directly in field with the aim to reduce the time to build the complete data set. Results highlight the great efficiency of the proposed approach to reduce the time to build the complete data set, to maximize the electronic nose capability of operating a qualitative classification of odour sources.

A novel tool for odor emission assessment in wastewater treatment plant

AbstractOdor emissions are one of the major environmental impact generated by wastewater treatment plants (WWTPs) perceived by exposed population. Consequently, the control of odor emissions is a relevant aspect that must be considered in the management of the WWTPs. Any efficient strategy for odor control was based on direct and/or indirect monitoring and characterization of odor emissions. The presented work focuses on the identification of new indirect indicators for the measurement of the odors emitted by different treatment units in a full-scale wastewater treatment plant, as to reduce the cost of environmental monitoring and the environmental impacts of the plant. The work focuses on the existing correlation in each treatment unit between the odor emission capacity (OEC) of wastewater and the odor concentration measured by dynamic olfactometry according to EN13725:2003 in ambient air. In addition the research shows the correlation between the organic contents measured by BOD5 and COD and the OEC of ...