Research Article: Hormones removal from municipal wastewater using ultrasound

Date Published: June 1, 2018

Publisher: Springer Berlin Heidelberg

Author(s): Aliakbar Roudbari, Mashallah Rezakazemi.

http://doi.org/10.1186/s13568-018-0621-4

Abstract

Estrogens are one of the micro-pollutants in the wastewater which have detrimental effects on water living organisms. The aim of this study was to evaluate the efficiency of ultrasound to reduce the estrogen (E1) and 17 beta-estradiol (E2) from municipal wastewater. Hence, a cylindrical batch reactor was designed. The effects of powers, frequency, exposure time and pH on reduction efficiency were investigated. The residual concentration of E1 and E2 hormones was measured in reactor effluent by electrochemiluminescence (ECL) method. The results showed that ultrasound removed 85–96% of both E1 and E2 hormones after 45 min while other parameters changes in the range of their operations. Also, the frequency and power of ultrasound had a significant effect on reduction efficiency of hormones while the exposure had no significant effect. Furthermore, the interaction of power and frequency reduced their efficacy to 64.3% (Pvalue = 0.005). The result also indicated that the ultrasound waves have high ability to reduce Steroid hormones from municipal wastewater. The proposed method can be considered as one of the significant strategies for reduction or destruction of hormones from wastewater due to the non-generation of dangerous by-products and the low energy consumption.

Partial Text

Estrogens are one of the micro-pollutants in wastewater which have detrimental effects on water living organisms (Azimi et al. 2017; Hamid and Eskicioglu 2012). These hormones are divided into five types: Progestin (Progesterone), Glucocorticosteroids (Cortisol), Mineral corticosteroids (Aldosterone), Androgen (Testosterone), and Estrogen (Nagarnaik et al. 2010). Estrone (E1) and 17 beta-estradiol (E2) are the most important estrogen hormones in wastewater which are excreted by all humans and animals (Guedes-Alonso et al. 2014). Estriol (E3) and 17-alpha-ethinyl estradiol (E4) are other estrogens which are found in smaller amounts in wastewater (Blair et al. 2013). The existence of these compounds in wastewater was firstly reported in 1965 (Hamid and Eskicioglu 2012) but was not seriously investigated by researchers until 1980 that the detrimental impacts of these hormones were confirmed on fish growth (Behera et al. 2011). Steroid hormones are endocrine-disrupting compounds in the body which have become one of the major concerns as wastewater effluent in the environment because of negative effects on human health, animals, and ecosystem balance (Aker et al. 2016; Mendoza et al. 2016). Estrogen in very low concentrations (less than 0.1 ng/L) interferes with reproduction of human, livestock, and wildlife and has a stimulatory effect on breast tumor growth (Ravindran et al. 2016). Some studies have shown its effect on uterine cancer, ovary and other cancers (Yi et al. 2016). These hormones either are produced naturally in the human and animal body or are found in some materials that humans deal with them on a daily basis. Detergents, shampoos, lotions, and cosmetics are new sources of these hormones in environment and wastewater.

Table 1 shows the wastewater characteristics which were used in the study. As can be seen, the wastewater was clearly representative of municipal wastewaters. The studies performed by Sun et al. (2016) and Renuka et al. (2016) showed similar results. The results showed that ultrasound waves had the high ability on reducing hormones E1 and E2 (Tables 2 and 3). Figure 2 shows the effect of power on E1 and E2 reduction. As can be seen, with increasing the ultrasound power increases the efficacy reduction of E1 and E2. Figure 3 shows the effect of frequency on E1 and E2 reduction. As can be seen, with increasing ultrasound frequency, the reduction efficacy of E1 and E2 has increased. Figure 4 shows the effect of exposure time on E1 and E2 reduction. As can be seen, with increasing exposure time, the reduction efficacy of E1 and E2 somewhat has increased but the not significant. Figure 5 shows the effect of pH on E1 and E2 reduction. As can be seen, with increasing pH, the reduction efficacy of E1 and E2 has increased.Table 2Reduction rate (%) of estrogen by ultrasound at different time, power, pH and frequency (Mean ± SD)pHPower (W)Frequency (KHz)Time (min)3060901203703012.4 ± 2.312.7 ± 1.413.1 ± 1.313.2 ± 1.33704513.3 ± 1.813.5 ± 1.613.8 ± 1.214.5 ± 1.23706014.3 ± 1.315.6 ± 1.415.8 ± 1.216.5 ± 1.331103020.5 ± 2.421.1 ± 2.121.5 ± 1.721.9 ± 1.631104522.3 ± 1.522.7 ± 1.522.9 ± 1.423.3 ± 1.131106023.5 ± 1.223.7 ± 1.224.1 ± 1.424.3 ± 1.27703026.3 ± 1.426.7 ± 1.229.6 ± 1.531.2 ± 1.47704532.5 ± 1.232.3 ± 1.133.8 ± 1.335.2 ± 1.67706031.5 ± 1.333.1 ± 1.235.6 ± 1.238.9 ± 1.871103039.1 ± 2.540.5 ± 2.940.8 ± 2.342.3 ± 3.171104542.1 ± 3.243.5 ± 2.744.9 ± 2.646.1 ± 2.571106046.0 ± 2.546.1 ± 2.847.8 ± 2.649.2 ± 2.510703067.1 ± 3.168.9 ± 3.669.5 ± 2.770.6 ± 2.810704570.8 ± 2.671.5 ± 2.574.2 ± 2.775.3 ± 2.610706075.6 ± 2.575.9 ± 2.677.5 ± 2.879.6 ± 2.6101103081.3 ± 2.681.9 ± 2.582.6 ± 3.184.6 ± 3.1101104585.8 ± 3.786.9 ± 2.687.2 ± 3.590.9 ± 3.2101106091.1 ± 3.191.2 ± 3.192.2 ± 3.294.2 ± 2.7Table 3Reduction rate (%) of 17 beta-estradiol by ultrasound at different time, power, pH and frequency (Mean ± SD)pHPower (W)Frequency (KHz)Time (min)3060901203703012.2 ± 1.812.5 ± 1.613.0 ± 1.113.1 ± 1.33704513.1 ± 1.213.2 ± 1.313.3 ± 1.213.7 ± 1.43706013.8 ± 1.114.5 ± 1.215.1 ± 1.215.8 ± 1.131103019.8 ± 1.321.0 ± 1.321.2 ± 1.221.6 ± 1.431104521.9 ± 1.322.3 ± 1.222.5 ± 1.423.1 ± 1.431106023.1 ± 1.423.5 ± 1.424.0 ± 1.324.1 ± 1.47703025.8 ± 1.626.4 ± 1.528.8 ± 1.530.8 ± 1.37704531.8 ± 1.232.1 ± 1.332.5 ± 1.234.5 ± 1.27706030.8 ± 1.332.5 ± 1.234.2 ± 1.437.5 ± 1.671103038.6 ± 1.339.8 ± 1.240.5 ± 1.241.8 ± 1.471104541.8 ± 1.342.9 ± 1.444.5 ± 1.345.8 ± 1.471106043.0 ± 1.245.6 ± 1.446.2 ± 1.348.2 ± 1.510703066.5 ± 2.367.8 ± 2.169.2 ± 2.270.8 ± 2.310704570.9 ± 2.472.3 ± 2.274.2 ± 2.375.5 ± 2.110706075.3 ± 2.275.9 ± 2.176.8 ± 2.378.5 ± 2.1101103081.9 ± 2.482.3 ± 2.382.5 ± 2.883.9 ± 2.6101104586.2 ± 2.586.9 ± 2.686.6 ± 2.888.9 ± 2.6101106090.9 ± 2.491.3 ± 2.591.8 ± 2.393.6 ± 2.2Fig. 2Effect of power on E1 and E2 reduction (frequency = 45 kHz, pH 7)Fig. 3Effect of frequency on E1 and E2 reduction (power = 70, pH 7)Fig. 4Effect of exposure time on E1 and E2 reduction (power = 110, frequency = 60 kHz)Fig. 5Effect of pH on E1 and E2 reduction (power = 110, frequency = 60 kHz)

In this study, the effect of power, frequency, exposure time, initial pH, and also the concurrent effect of power and frequency on Estrone and 17 beta-Estradiol reduction from municipal wastewater were investigated. According to the results, ultrasound can reduce 85–96% of E1 and E2 after 45 min while other parameters changes in the range of their operations and ultrasound frequency and power had a significant effect on reduction efficiency but exposure time had no significant effect. Also despite the fact that the power and frequency individually had a significant effect on hormones reduction, but their concurrent effect was reductive. With the increasing initial pH, reduction efficacy increased due to the increased production of hydroxyl radicals. The result indicated that the ultrasound has high ability to remove Steroid hormones from municipal wastewater, so due to non-generation of dangerous by-products and low electricity requirement; this method can be considered as a valuable strategy for reduction or destruction of hormones from water resources.

 

Source:

http://doi.org/10.1186/s13568-018-0621-4

 

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