Water reclamation with hybrid coagulation–ceramic microfiltration: first part of a long-term pilot study in Portugal

Abstract

Sustainable water management must nowadays consider alternative water sources and the use of reclaimed water is a good candidate. Low-pressure ceramic membrane filtration is an emerging option for safe water reclamation given its high mechanical and chemical robustness with safety and operational advantages. One-year pilot studies of hybrid coagulation-ceramic filtration were developed in Portugal in two wastewater treatment plants in the Lisbon metropolitan area. The results obtained demonstrated the technology's effectiveness, reliability and efficiency towards water quality, with the hybrid process consistently producing water highly clarified (monthly median <0.1 NTU), bacteria-free and with reduced organic matter content, regardless of the strong and severe variations in its intake.

Pilot Studies and Cost Analysis of Hybrid Powdered Activated Carbon/Ceramic Microfiltration for Controlling Pharmaceutical Compounds and Organic Matter in Water Reclamation

“…Although water reuse is an important tool for extending the water life cycle and in full compliance with the circular economy objectives, water reuse in the European Union has not yet been seriously tackled and is far below its potential. Nevertheless, in the context of adapting to climate change, a credible momentum to drive changes has been created in the last five years, confirmed by new international strategies such as those of the International Organization for Standardization (ISO/TC 282 Water Reuse) and, at an European level, the targeting of a substantial increase in recycling and safe reuse globally by 2030 (United Nations (UN) Sustainable Development Goal on Water, SDG 6), the establishment of water reuse as a top priority area (Strategic Implementation Plan of the European In previous studies with the same pilot [16], one-year 24/7 demonstration of coagulation-ceramic MF (0.1 µm) was developed in Portugal in two WWTPs in the Lisbon metropolitan area. The results obtained demonstrated the technology's effectiveness, reliability and efficiency towards water quality, with the process consistently producing highly clarified (monthly median < 0.1 NTU) and bacteria-free water, regardless of the severe variations in its intake.…”

“…Water 2020, 12, x FOR PEER REVIEW 3 of 13 In previous studies with the same pilot [16], one-year 24/7 demonstration of coagulation-ceramic MF (0.1 μm) was developed in Portugal in two WWTPs in the Lisbon metropolitan area. The results obtained demonstrated the technology's effectiveness, reliability and efficiency towards water quality, with the process consistently producing highly clarified (monthly median < 0.1 NTU) and bacteria-free water, regardless of the severe variations in its intake.…”

“…Each filtration cycle was followed by a backwash with pressurised air and permeate to remove the accumulated solids. Further details of the pilot facility and of its operation can be found in Viegas et al [16].…”

“…After the previous operational optimisation performed [16], the tests were conducted in dead-end mode, at a constant flux (100 L/(m 2 h), in short lmh), dosing FeCl3 coagulant (10 mg Fe/L) The PAC/MF pilot was fed using a submersible pump located in the sand-filtered effluent tank of the WWTP. The pilot contained a stirred contact tank of 20 L, to where the intake water was pumped, and to where PAC slurry was also continuously dosed with a peristaltic pump during the PAC tank dosing periods.…”

“…After the previous operational optimisation performed [16], the tests were conducted in dead-end mode, at a constant flux (100 L/(m 2 h), in short lmh), dosing FeCl 3 coagulant (10 mg Fe/L) and PAC Water 2020, 12, 33 4 of 13 (15 mg/L, Norit SAE Super, Cabot), and 60-min filtration time followed by backwash. Besides the backwash, the cleaning strategies also included chemically enhanced backwashing (CEB), with two CEBs per day, one with sulfuric acid and one with sodium hypochlorite.…”