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Recently, the concentration of emerging contaminants is increasing in drinking water sources, industrial wastewater, and reclaimed water. It is not possible to remove the emerging contaminants using conventional methods, and the interest to use nanomembrane-based filtration is getting attention. A nanomembrane-based filtration can be manipulated without the use of any special equipment. Different research findings reported better removal of emerging contaminants has been achieved using nanomembrane-based filtration. Moreover, new developments have been examined and implemented at different levels and are expected to continue. Therefore, this chapter provides a brief overview of recent developments on nanomembrane-based filtration processes in the removal of emerging contaminants from drinking water sources, industrial wastewater, and reclaimed water.

In this study, activated carbon was prepared from locally available bamboo (Arundinaria alpina) in Ethiopia to remove Pb (II) from wastewater. Various effects such as solution pH, initial Pb (II) ion concentration, and adsorbent dose were investigated and accordingly discussed, and the process was carried out on a batch adsorption base. Dried Arundinaria alpina stem was activated with potassium hydroxide (KOH) at a ratio of 1 : 1 (w/v) and carbonized in a furnace at three temperature ranges (500oC, 600oC, and 700oC) for 3 h. The physicochemical of Arundinaria alpina stem activated carbon (AASAC) was investigated and the resultant of 500oC treatment setup is found as ideal in terms of yield (40.6 g), ash (3.5%), porosity (0.704%), moisture (7.7%), and iodine number (814.69 mg/g). The further characterization of ideal AASAC was carried out by scanning electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy, and Fourier transform infra-red (FTIR). The optimum Pb (II) removal efficiency of AASAC was 99.8% at pH 5 in a synthetic solution, but the efficiency declined to 60.42% on real industrial wastewater due to the presence of its mixed pollutant nature. Freundlich isotherm model is more favorable than Langmuir with a high correlation coefficient (R2-0.9496) for Pb (II) adsorption. The study revealed that AASAC has a potential adsorption efficiency to remove the Pb (II) ion from the aqueous solution which is also recommended as an adsorbent for real industry wastewater treatment.

Dyes and other chemicals laden wastewater is a main environmental concern for increasing the textile industries in many parts of the world. Textile industries consume different kinds of manmade dyes or other chemicals and release huge extents of highly polluted water into the environment. This excessive dye laden wastewater has great impacts on photosynthetic activity in aquatic plants and animals, for example, fish. It may also affect human health due to the presence of components like heavy metals and chlorine in manmade dyes. Thus, wastewater effluent from textile industries must be treated before discharge into the water body. Treatment technologies observed in this review paper include biological treatment methods (fungi, algae, bacteria, and microbial fuel cells), chemical treatment methods (photocatalytic oxidation, ozone, and Fenton’s process), and physicochemical treatment methods (adsorption, ion exchange, coagulation, and filtration). This review also includes the hybrid treatment methods and their cost per m3 of treated wastewater analysis. There are alternative wastewater treatments systems at different steps of effluent generated from the textile operational unit recommend in this review work.

This study focused on the evaluation of Aloe steudneri gel for textile wastewater clarification with identification of major phytochemical groups and physicochemical characteristics of Aloe steudneri. Optimization of pH, flocculant dose, mixing speed and time were studied for Aloe steudneri gel and synthetic polyacrylamide. A jar test was used to perform the flocculation at optimum conditions (pH 7.3, flocculant dose 33 ml, mixing time 20 minutes and speed 61 rpm). Phytochemical groups like tannins, flavonoids and saponins were identified and the gel showed a good result of 1.9 g H2O/dry polymer for swelling capacity and 6.2 g oil/weight for fat adsorption capacity. At the optimum conditions, the turbidity removal was 92.3% for Aloe steudneri gel and 92.7% for polyacrylamide. Moreover, the removal efficiencies for chemical oxygen demand, 5-day biological oxygen demand, total suspended solids and lead were 76.8%, 83.5%, 57.9% and 77% for Aloe steudneri gel and 78%, 89%, 51% and 72% for polyacrylamide, respectively. Therefore, it is possible to conclude that Aloe steudneri gel can substitute the polyacrylamide as there are no significant differences in their removal efficiencies.

This study aimed to investigate the potential of Canna indica stem-based activated carbon (CISAC) for the removal of Pb (II) ions from synthetic solution and paint industry wastewater. The effects of pH, initial Pb (II) ion concentration, and adsorbent dose were studied using an aqueous solution prepared using pure lead nitrate (Pb(NO₃)₂) on a batch mode. Dried Canna indica stem (CIS) was carbonized in a rectangular furnace at 500°C for 2 h and treated with phosphoric acid (H3PO4) at a ratio of 1 : 1 (w/v). Results showed that the CISAC had 5.4% of moisture, 5.0% of ash, 26.7% of volatile matter, 62.9% of fixed carbon, and 797.5 mg/g of iodine number. The Fourier Transform Infrared (FTIR) results showed that the hydroxyl, carboxyl, and phenolic functional groups were dominant in the CISAC surface. Physicochemical characteristics revealed that raw wastewater had a concentration of 4.6 mg/L Pb (II), 3 mg/L Cu (II), 171 mg/L BOD5, 2402 mg/L COD, and 619 mg/L TSS. Better removal of Pb (II) ion from aqueous solution was achieved at a pH of 5.5, initial Pb (II) concentration of 102.4 mg/L, and an adsorbent dose of 1.4 g using response surface methodology. The highest removal efficiencies of Pb (II) which was achieved from aqueous solution and paint wastewater were 98% and 70%, respectively. The experimental data are fitted with Langmuir and Freundlich isothermic models. The results suggested CISAC as a promising adsorbent to remove Pb (II) ion from paint industry wastewater.