Submerged Ultrafiltration System Provides The City Of São Paulo Drinking Water In Times Of Drought Ben Antrim*, Kevin Phillips*, HeniaYacubowicz*, Ruming Pang** and Vanessa Brusius*** * Koch Membrane Systems, 850 Main Street, Wilmington, MA 01810, USA. (E-mail:
[email protected];
[email protected];
[email protected]) ** Koch Membrane Systems, (A Division of Koch Chemical Technology Singapore Pte. Ltd.) 391B Orchard Road, #15-05/08, Ngee Ann City Tower B, Singapore 238855 (E-mail:
[email protected]) *** Koch Tecnologia Química, Ltda. Rua Catequese, 223 – 2º Andar, 05502-020 – Butantã, São Paulo, SP (E-mail:
[email protected])
Introduction
Methodology
The existing conventional water treatment plant in the Alto da Boa Vista neighborhood of São Paulo (ABV) treats reservoir water via coagulation, clarification and sand filtration, providing drinking water to the city of São Paulo. The ABV plant capacity is 54,000 m3/hr.
The PURON HF Ultrafiltration submerged hollow fiber product was selected for this project for its advantages and performance characteristics:
The ABV plant could not expand its clarifiers and sand filters due to space limitations, and as demand for drinking water continued to increase, the plant management sought a way to add 7,200 m3/hr water production at minimal impact on footprint. SABESP, the São Paulo state water and waste management company contracted Centroprojekt do Brasil to engineer and commission the facility.
• Excellent filtered water quality meeting all drinking water targets, including turbidity reduction to less than 0.1 NTU • Small footprint allowing the expansion to take place within the available space • Ability to operate at high influent solid levels at high water recovery rate (>95%) • Low operating costs due to low power consumption and stable performance under an infrequent cleaning regimen
Figure 1: Guarapiranga Reservoir
• Robust, PVDF reinforced membrane for reliable, long term service
Figure 2: PURON HF Module
Results & Discussion The Ultrafiltration system was installed in two phases, each phase included 6 membrane trains. Each phase produces 3,600 m3/hr (1,000 lps). Due to severe drought conditions the project was executed on a fast track and started to produce water before some ancillaries, such as drains, CIP system and compressors were in place. However, despite the challenges, the system started to produce water within 6 months of signing the contract.
The Ultrafiltration system takes 3.5 times less footprint than the conventional system per m3/day water produced.
Additional challenges required rapid action to optimize pretreatment, coagulation, backflush and membrane cleaning regimens to address high organics in the feedwater, as well as seasonal elevated algae concentrations during the system commissioning. The high concentration of algae during these periods has historically posed a challenge for the sand filters, limiting production capacity. Since installation in late 2014, the PURON HF ultrafiltration system has met all targets, including production capacity, feed water recovery and effluent quality. The system has demonstrated an excellent ability to handle high solids and algae loads.
Figure 3: Bird-eye photograph of the ABV system. Ultrafiltration system in red circle.
The ultrafiltration system showed full recovery of membrane permeability after a standard acid followed by chlorine CIP procedure. With a demonstrated effective cleaning frequency of once per year, the chemical consumption of the plant is very low.
The Ultrafiltration system has demonstrated stable performance over a year, independent of variations in feed quality and seasonal algae peaks. Raw water varies between 1-10 NTU, 10-100 mg/L Total Hardness and 0.05-0.5 mg/L dissolved iron.
Figure 4: Flux and permeability of Train 1 of the ABV Submerged system (phase 1) showing successful recovery cleaning. 1 year of operation is shown, including the initial process optimization.
Figure 5: Flux and permeability of Train 9 of the ABV Submerged system (phase 2) showing stable performance over 6 months.
Conclusions The benefits of PURON HF hollow fiber ultrafiltration have been demonstrated at the ABV drinking water treatment plant in Sao Paulo. At the same time as demand is increasing, so are the requirements for water quality. Concurrently, water treatment facilities are forced to draw on more challenging raw water sources. Given this combination of challenges, the PURON HF reinforced hollow fiber with its high solids tolerance and robust operations capability is an ideal solution, especially for large drinking water plants.
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