Results of a survey-based study to identify Common Optimization Practices in Drinking Water Membrane Processes

In Sweden, the adoption of membrane technology for drinking water production is increasing, prompting many water producers to consider substantial investments in new membrane facilities. Ensuring the sustainability of membrane operation in terms of cost,environmental impact, and long-term performance is a top priority. This descriptive study aims to identify common operational trends or practices for optimizing membrane filtration plants. Membrane filtration entails significant costs, encompassing initial investment energy, and chemical consumption, comprising both capital and operating costs.Conducted on behalf of the Swedish Water Association (Svenskt Vatten), Sweco, a consulting company, carried out this study. It involved interviews with European drinking water producers operating membrane plants, as well as discussions with membranesuppliers and manufacturers to draw insights from their collective expertise. The results show that the predominant approach to operating parameters is to follow the supplier’s recommendations to ensure that the supplier’s warranties are honoured. As a result, plant owners tend to refrain from optimising operations or changing parameters without consulting the supplier. Membrane washing is emerging as a critical operational step with significant impact on membrane performance and lifetime. Participating water organisations indicate that ultrafilter membrane suppliers often advocate the use of coagulants to stabilise membrane operation and reduce reliance on chemically enhanced backwash.In a recurring theme among participants, many water producers emphasized that their selection of suppliers was primarily driven by the assurance of supplier guarantees and the presence of a robust technical support team, rather than direct sustainabilityconsiderations. Sustainability concerns were addressed indirectly through a focus on achieving long product lifespan, minimizing chemical usage, and reducing energy consumption.Additionally, the study delves into future trends concerning membrane manufacturing, which currently bears a substantial environmental footprint due to the utilization of harmful solvents and the production of polymers used in membrane construction. Ongoing research endeavours aim to replace toxic solvents with sustainable alternatives and investigate ecofriendlypolymer options, reflecting a growing focus on environmental sustainability in this field.In conclusion, the report offers valuable insights and recommendations for designing tender documents tailored to Swedish conditions for membrane installations.