A Step Forward to the Characterization of Secondary Effluents to Predict Membrane Fouling in a Subsequent Ultrafiltration

Anderson Alejandro Benites-Zelaya,Eva Ferrer-Polonio,José Luis Soler-Cabezas,José Antonio Mendoza-Roca,María Cinta Vincent-Vela

doi:10.3390/w12071975

Anderson Alejandro Benites-Zelaya, Eva Ferrer-Polonio + Show 3 more

Open Access

https://doi.org/10.3390/w12071975

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Journal: Water	Publication Date: Jul 13, 2020
Citations: 5	License type: CC BY 4.0

Affiliation: Universitat Politècnica de València

Abstract

Nowadays, wastewater reuse in Mediterranean countries is necessary to cover the water demand. This contributes to the protection of the environment and encourages the circular economy. Due to increasingly strict regulation, the secondary effluent of a wastewater treatment plant requires further (tertiary) treatment to reach enough quality for its reuse in agriculture. Ultrafiltration is a membrane technique suitable for tertiary treatment. However, the most important drawback of ultrafiltration is membrane fouling. The aim of this work is to predict membrane fouling and ultrafiltered wastewater permeate quality for a particular membrane, using the information given by an exhaustive secondary effluent characterization. For this, ultrafiltration of real and simulated wastewaters and of their components after fractionation has been performed. In order to better characterize the secondary effluent, resin fractionation and further membrane ultrafiltration of the generated fractions and wastewater were performed. The results indicated that hydrophobic substances were lower than hydrophilic ones in the secondary effluent. Supelite DAX-8, Amberlite XAD-4 and Amberlite IRA-958 resins were found not to be specific for humic acids, proteins and carbohydrates, which are the main components of the effluent organic matter. Two models have been performed using statistics (partial least squares, PLS) and an artificial neural network (ANN), respectively. The results showed that the ANN model predicted permeate quality and membrane fouling with higher accuracy than PLS.

Highlights

Wastewater reclamation and reuse is a topic that has been deeply studied in recent years
Ultrafiltration (UF) seems to be one of the most suitable techniques to be implemented in the future for reusing wastewater in agriculture, as it achieved a higher removal of pathogens than the above-mentioned processes
The analysis of protein, carbohydrate and humic substances in secondary effluents is of great importance when membrane processes are used as tertiary treatments after a biological process

Summary

Introduction

Wastewater reclamation and reuse is a topic that has been deeply studied in recent years. The required validation monitoring implies for the highest quality water (class A) that the implemented processes have to achieve removal efficiencies higher or equal to 5 log of Escherichia coli and of the protozoa indicator (Clostridium perfringens spores) and higher or equal to 6 log of viruses This means that the widely used conventional processes, consisting of coagulation–flocculation–sedimentation plus filtration and disinfection with chlorination or UV irradiation, are called into question, as they cannot offer the required efficiencies [2,3]. Water 2020, 12, 1975 are biologically and structurally different; the use of one specific chemical or UV irradiation for disinfection may not be efficient for all of them [4,5,6] In this context, ultrafiltration (UF) seems to be one of the most suitable techniques to be implemented in the future for reusing wastewater in agriculture, as it achieved a higher removal of pathogens than the above-mentioned processes.

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