Вестник МГТУ. 2018, том 21, № 1.

Васильева Ж. В. и др. Получение биофлокулянтов из биомассы активного ила… 82 (NH 2 ) 2 CO method, followed by the EDTA method, the lowest efficiency is shown by the extraction method CH 3 COOH. Table 2. EPS extraction efficiency ( n = 10) Таблица 2. Эффективность экстракции ВПВ ( n = 10) Property The EDTA method The (NH 2 ) 2 CO method The CH 3 COOH method Extraction efficiency (converted by the suspended solids concentration of activated sludge), % 13.08 ± 3.57 15.2 ± 4.37 5.22 ± 2.79 The resulting dry preparations of EPS are powder which varies from light gray or brown to dark green color depending on the technology. Fig. 1 shows EPS samples obtained via the three approved technologies. а b c Fig. 1. Samples of EPS (dry) obtained via three technologies: a – the EDTA method; b – the (NH 2 ) 2 CO method; c – the CH 3 COOH method Рис. 1. Образцы ВПВ (сухие), полученные по технологиям: a – метод EDTA; b – метод (NH 2 ) 2 CO; c – метод CH 3 COOH The study of the swollen biopolymers composition is shown in Fig. 2. The bioflocculant obtained with the EDTA method has a mucous, stretch-like structure resembling another natural bioflocculant – gelatin; the structure of the biopolymer obtained with the (NH 2 ) 2 CO method has the form of cotton particles. EPS received via the CH 3 COOH method have a granular structure. а b c Fig. 2. Samples of EPS (swollen) obtained due to the three approved technologies: a – the EDTA method; b – the (NH 2 ) 2 CO method; c – the CH 3 COOH method Рис. 2. Образцы ВПВ (набухшие), полученные по технологиям: а – метод EDTA; b – метод (NH 2 ) 2 CO; c – метод CH 3 COOH The resulting bioflocculants are pre-colored with fluorochrome acridine orange under illumination with ultraviolet rays through the green filter, and have shown the red and green fluorescence (Fig. 3). This suggests that EPS contain mainly polysaccharides (red luminescence) and protein structures (green luminescence) of different functional groups in their composition. In this case, the samples obtained with the EDTA method have contained mainly proteins with small impregnations of polysaccharides, and in contrast, the samples obtained with the CH 3 COOH method have contained higher quantities of polysaccharide.