Evaluation and Mapping of Sustainable Water and Wastewater Treatment with Membrane Processes in South Africa and Sweden

Membrane technology is crucial to achieving Sustainable Development Goal No. 6 of clean water and sanitation for all. Despite its numerous benefits, high capital and operating costs pose major challenges. Recent research has focused on sustainable materials as membranes and more effective cleaning regimes to reduce costs and improve membrane lifespan. While South Africa and Sweden have both begun using membrane technology for water and wastewater treatment, it remains relatively rare. Collaborations through SASUF aim to evaluate and share best practices. Although MBRs have produced high-quality effluent in South Africa, cost, maintenance, and membrane replacement, as well as river pollution, remain major considerations. In contrast, Sweden has seen large-scale membrane installations in drinking water and wastewater treatment plants. Establishing working membrane references is crucial to the success of membrane technology, which is well-established globally but often requires local adaptations. Collaborations between the two countries are essential to support this approach by sharing knowledge and learning from each other

Integration of cross-flow filtration in the fruit juice industry

The market for membrane technology in the food and beverage industries increased during the last two decades to a market volume of about € 150 million and is now the second biggest industrial market for membranes after municipal water treatment in Europe. The aim of this study is to highlight new application concepts for membrane processes either by replacing conventional separation processes or by combining membrane processes with conventional separation technologies to achieve optimised solutions. The first part of this work demonstrates potential applications in the fruit juice industry. In this industry, kieselguhr filtration or ultrafiltration is used to clarify apple juice by removing suspended solids or other high molecular solids such as proteins and starch. A new concept combining a high-speed separator with spiral wound ultrafiltration modules will be proposed as an alternative to kieselguhr filtration or ultrafiltration as stand alone unit. Further, for the concentration of apple juice a combination of reverse osmosis and evaporation will be discussed in comparison to only evaporation. The focus in the second part of this work is on the brewing industry. In the traditional brewing process clarification of beer after fermentation and maturation is achieved by a separator followed by kieselguhr filtration. Microfiltration will be introduced as a replacement for kieselguhr filtration to clarify the beer by removing yeast, micro-organisms and haze without affecting the taste. Another novel use of cross-flow microfiltration in breweries is the recovery of beer from tank bottoms. After fermentation, yeast with 1.5 to 2 % of the total beer volume settles at the bottom of the fermentation vessels. By using microfiltration the beer, which would be lost if not recovered, can be separated from the yeast. Overall this work demonstrates the potential of membrane processes in the beverage industry and the importance of process optimisation and integration

Water recovery and recycle in the PVC production: A novel approach using membrane technology

The production of 1 ton of PVC requires 2.0 - 2.5 m3 of demineralised water. Some of the water is lost in the process, e.g. as vapor during the drying of the PVC or as sealing water, while approx. 80% of the water could potentially be recycled. In today’s installations only about 20 – 25% of the water recovered by the PVC decanter is used for flushing of the facilities, while 75 – 80% is discharged from the facilities after biological treamtent. The key challenges preventing the direct recycling of the water from the decanter to be used not only for flushing but also for the polymerisation is the presence of residual PVC particles and inhibitors. A new concept based on reverse osmosis does not only remove the residual PVC particles but also the inhibitors and conductivity down to levels allowing the direct recycle of 75 – 80 % of the water from the decanter to the polymerisation step. In this concept the water from the decanter is treated with special reverse osmosis membranes and modules. The result is a permeate stream suitable for direct recycling not only reducing the consumption of de-mineralised fresh water but also the amount of waste water to be treated. Applying a optimsed cleaning method membrane fluxes and thus the plant capacity can be maintained over long periods

Membrane processes for sugar and starch processing

Sugars and starches belong to the category of carbohydrates, which are important energy sources for organisms and nonessential nutrients in the human diet. Sugars are mono- or disaccharides that can be immediately transformed to energy by organisms. Starches, on the other hand, are polysaccharides, a space-efficient storage of energy for organisms. Before transforming polysaccharides into energy for organisms, they have to be therefore converted into mono/disaccharides, which can be achieved by different metabolisms. Hence, both starches and sugars play an important role in human nutrition and consequently the starch and sugar processing industry is a key segment of the food industry. The introduction of membrane technology into the sugar and starch industry can be related to the invention of the phase inversion membrane by Sidney and Sourirajan in the 1960s [1]. This invention started the rapid growth of the membrane market and the large-scale introduction of membranes to the food industry in general and subsequently to the starch and sugar industry