Assessing Pretreatment Methods to Mitigate Nanofiltration Fouling
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Infrastructure and environmental engineering (MPIEE), MSc
Publicerad
2024
Författare
hallset, Beate
Jakobsson, Emma
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Globally, water scarcity is a critical issue affecting millions of people, exacerbated
by increasing population and climate change. In countries like Sweden, where water
availability is sufficient, this vital resource is often taken for granted. However, the
extensive reliance on centralised water infrastructure in Sweden has its limitations.
To address these challenges, modular drinking water treatment systems (MDWTS)
offer a viable solution. These systems can serve as a complement to, or in the ab sence of, centralised water infrastructure, ensuring sustainable water management
and availability. Membrane filtration is a compact treatment method applicable for
various raw water qualities, which makes it suitable to implement in a MDWTS.
However, membrane modules face an obstacle due to the risk of fouling caused by
organic and inorganic compounds in the raw water. Fouling results in a reduc tion of treatment efficiency, while increasing the need of operational and economic
resources. The aim of this thesis is to suggest suitable pretreatment methods for
raw water to mitigate membrane fouling in a MDWTS, where nanofiltration acts
as the main treatment step. The issue was investigated through a study of litera ture, identifying key foulants and possible pretreatment methods. The key foulants
identified in the study of literature are particles, natural organic matter, iron, man ganese, calcium, magnesium, aluminium and silica. In addition, bench studies on a
biological activated carbon filter, an alkaline filter and a charged sieve followed by
a disc filter were performed to evaluate their potential to operate as pretreatment.
Further, the findings were applied to three water types representing water qualities
from three water sources in Sweden, aiming to suggest pretreatment chains to re duce key foulants. The pretreatment chains suggested in the result for the three
water types are all spatially manageable in a MDWTS. Although, for one of the
water types, the pretreatment may be challenging to implement due to operational
complexity. To include additional water qualities, a general procedure connecting
key foulants to suitable pretreatment methods is presented. Due to the complexity
of nanofiltration fouling and the possible interactions between key foulants and the
different steps in the pretreatment chain, pilot studies are necessary to evaluate the
fouling mitigation. By validating the framework through pilot testing, this work can
contribute to enhancing nanofiltration performance and further the development of
MDWTS
Beskrivning
Ämne/nyckelord
MDWTS , Nanofiltration , Fouling , Pretreatment.