Due to concentration differences, normal osmosis occurs, pulling water from the permeate side to the feed side, and cleans the pores of the membrane. Forward osmosis works for processes that have high ionic concentration (conductivity) reject that stays side by side with the low concentration permeate head that is separated by a semipermeable membrane. Online management includes forward flushing at higher flow/velocity of feed or backward flushing (UF, MF) and forward osmosis (RO). The rise of differential pressure across the membrane and the decline of the permeate flow suggest that online management is required. Use of well-pretreated feed and monitoring of the fouling initiation stages leads to preventive actions for steady performance. In order to minimize chemical cleaning, online membrane performance management by physical methods is getting popular and does not involve chemical addition or plant shutdown. The developed BMPs show that the previously completed enhanced coagulation-GAC sorption process, when combined with an online non-chemical flushing regimen and proper membrane preservation, keeps the flux readings high, resolving frequent fouling and cleaning problems of the RO membrane. The issue of RO membrane fouling and subsequent flux decline was directly related to the presence of soluble microbial products, specifically dissolved organic matter (DOM) in the MBR effluent. Physical and chemical analyses along with visual inspection of the membrane surface using scanning electron microscopy (SEM), energy diffusive X-ray (EDX) and Fourier transform infrared (FTIR) spectroscopy were completed. As a result, experiments were completed on treated fruit processing wastewater to identify the causes of fouling that originated from the MBR effluent and develop best management practices (BMPs) to minimize fouling of the RO membrane. However, fouling of the RO membrane causes operational challenges. A good alternative is an MBR system to treat the processing wastewater, followed by tertiary treatment using a reverse osmosis (RO) unit to enable water reuse. Fruit processing facilities are looking for ways to reduce water consumption to counter the impact of climate change.
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