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Water Reuse and Recycling
Published in Maulin P. Shah, Removal of Refractory Pollutants from Wastewater Treatment Plants, 2021
Khushboo Dasauni, Divya, Tapan K. Nailwal
The membrane filtration process can generally be defined as a separation process involving materials that allow certain molecules to pass through. This material is a semi-permeable membrane with a certain pore size range. The types of membrane filtration include reverse osmosis (RO), nanofiltration (NF), ultrafiltration (UF), and microfiltration (MF). Efficient membranes should have high pollutant retention rates, excellent durability, a high flux, low maintenance costs, and high chemical resistance (Praneeth et al., 2014). Membrane filtration is considered as safe and environmentally friendly (Abid et al., 2012). Membrane technology has been used to treat municipal, industrial, and textile wastewater, as well as beer wastewater. However, the application of membrane filtration has its advantages and disadvantages. The most famous advantage of membrane filtration is the quality of treated wastewater, because the system can effectively remove physical, microbiological, and chemical pollutants compared with other systems. However, due to its high maintenance and operating costs, its disadvantages outweigh its advantages, especially for application in developing countries. The pressure required for membrane filtration depends on the pore size, and the main challenge associated with membrane filtration is membrane fouling (Hosseinzadeh et al., 2013 and Pouet et al., 2014).
Treatment of Palm Oil Mill Effluents
Published in Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang, Treatment of Industrial Effluents, 2019
Mihir Kumar Purkait, Piyal Mondal, Chang-Tang Chang
Membrane filtration is one of the most leading methods that is being used to treat POME. The process of separation by membrane filtration technique is one of the effective treatments of POME. This is because the use of membrane filtration process has several advantages, which include using less energy, being environmentally friendly, easy to operate, and does not require much space. Process membrane will become an important tool for improving water quality. In addition, membrane filtration can be applied across a wide range of industries; the quality of treated water is more consistent regardless of influent variation; it can be used in a process to allow the recycling of selected waste streams within a plant; and highly skilled operators would not be required since the plant can be fully automated (Cheryan and Rajagopalan, 1998).
Selenium: Environmental significance, pollution, and biological treatment technologies
Published in Lea Chua Tan, Anaerobic treatment of mine wastewater for the removal of selenate and its co-contaminants, 2018
L.C. Tan, Y.V. Nancharaiah, E.D. van Hullebusch, P.N.L. Lens
Physical treatment has the advantage of being well established particularly for drinking water and municipal wastewater treatment and therefore the mechanisms and operational parameters are well understood. Additionally, with the use of membrane systems, space requirements are minimized and regulatory selenium limits are achieved. However, membrane filtration has major disadvantages of high energy and capital cost for operation and maintenance. Moreover, generation of concentrated waste or brine adds the additional burden of post-treatment and disposal issues. In the case of ion exchange, the process is commonly employed in many industrial wastewaters but has seen little success for selenium removal due to competition with other anions, which are present at much higher concentrations as compared to selenium oxyanions, quickly saturating the resins and causing a low selenium removal efficiency (NSMP 2007). Pre-treatment of the wastewater feed for other anions (e.g., sulfate) is therefore necessary before applying the ion exchange system in order to avoid inhibition on the selenium removal.
Treatment options for nanofiltration and reverse osmosis concentrates from municipal wastewater treatment: A review
Published in Critical Reviews in Environmental Science and Technology, 2019
Kimmo Arola, Bart Van der Bruggen, Mika Mänttäri, Mari Kallioinen
Various membrane filtration technologies are already widely used in water and wastewater treatment processes such as water reclamation. Concentrate produced in membrane filtration, such as nanofiltration or reverse osmosis, is usually a voluminous waste stream, the further treatment of which can be challenging. Currently (2018), potentially valuable components in these concentrates are usually not recovered and utilized. The aim of this critical review was to identify feasible membrane concentrate management strategies for concentrates originating from municipal wastewater treatment that not only minimize the amount of waste but also enable the recovery of valuable components, mainly nutrients such as calcium phosphate or magnesium ammonium phosphate hexahydrate (MAP). It was concluded that one single treatment technology is insufficient to enable advanced membrane concentrate treatment that meets the multiple goals set for concentrate treatment such as minimized amount of waste and recovery of valuable components, all this without risking any safety aspects. Thus, hybrid processes that could involve technologies such as shear enhanced membrane filtration, electrodialysis, advanced oxidation and nutrient recovery via precipitation/crystallization are required in order to convert membrane concentrates from waste to value.
Wax removal from textile wastewater using an innovative hybrid baffle tank
Published in The Journal of The Textile Institute, 2021
Hamidreza Rashidi, Nik Meriam Nik Sulaiman, Nur Awanis Hashim, Lori Bradford, Hashem Asgharnejad, Maryam Madani Larijani
Among all standard wastewater treatment techniques, membrane filtration has been noteworthy in the last decades for water and wastewater treatment (Lau & Ismail, 2009; Pendse et al., 2019). The presence of wax and oil, however, can negatively affect the effectiveness of membrane-based treatment due to factors such as flux decline and fouling when using for wastewater treatment in industrial effluents such as textile industries (Padaki et al., 2015; Shokrkar et al., 2012). Although various studies have considered the application of natural fibrous sorbent as an effective and environmentally friendly wax-removal method dealing with different oil types in wastewaters (Liu et al., 2014; Xue et al., 2013), fewer researchers have explained paraffin wax and its derivatives in batik plants wastewater. Some studies applied fiber-based separation methods to remove oil and paraffin from water and wastewater with noticeably acceptable efficiency (more than 90% contaminant removal) (Wong et al., 2013). Gravity separation followed by skimming is another generally effective method to remove free oil (non-emulsion) in both solid and liquid phases (Angelova et al., 2011). New methods such as Dissolved Air Flotation (DAF) and emulsifier application followed by gravity separation have been used to improve the skimming process along with increasing the respective wax and oil removal efficiency in effluent-treatment plants (Cheryan & Rajagopalan, 1998). When considering the advantages and disadvantages of all methods, DAF, skimming and sedimentation has drawn more attention and are commonly applied methods of wax removal in industrial wastewater treatment (Pintor et al., 2016).
Arsenic exposure from groundwater: environmental contamination, human health effects, and sustainable solutions
Published in Journal of Toxicology and Environmental Health, Part B, 2021
Elida Cristina Monteiro De Oliveira, Evelyn Siqueira Caixeta, Vanessa Santana Vieira Santos, Boscolli Barbosa Pereira
Membrane filtration processes also contribute substantially to the efficient removal of As from water. Membranes are typically synthetic materials composed of pores which allow specific constituents of a mixture to pass through them while retaining other constituents, thus acting as selective barriers (US Epa 2000). The 4 most popular membrane filtration processes include microfiltration (membrane pore size 0.1–10 µm), ultrafiltration (membrane pore size 0.01–0.1 µm), nanofiltration (membrane pore size 0.001–0.01 µm), and reverse osmosis (membrane pore size 0.0001 µm) (Choong et al. 2007; Sarkar and Paul 2016).