Вестник МГТУ. 2018, том 21, № 1.

Васильева Ж. В. и др. Получение биофлокулянтов из биомассы активного ила… 84 The next stage of work has been determined by the need to establish the feasibility of increasing bioflocculants dose to improve the degree of wastewater treatment. It has been found out that in case of increasing the bioflocculant dose from 1 g/l to 10 g/l, efficiency of wastewater treatment is significantly increased as well (Table 4). Thus, the removal efficiencies of weighted substances has increased from 25.78 ± 3.45 to 74.21 ± 0.0 %, the removal efficiencies of turbidity – from 27.97 ± 6.1 to 69.46 ± 0.0 %. Table 4. Improving the degree of wastewater treatment with increased bioflocculant dose (the EDTA method) Таблица 4. Улучшение степени очистки сточных вод с увеличением дозы биофлокулянта, полученного методом EDTA Constituent Untreated wastewater Treated wastewater by EPS 1 g/l 10 g/l Concentration, mg/l Treatment efficiency, % Concentration, mg/l Treatment efficiency, % Total suspended solids, mg/l 620 ± 22.95 465 ± 30.89 25.78 ± 3.45 159.8 ± 27.66 74.21 ± 6.8 Optical density, l/cm 0.63 ± 0.34 0.46 ± 0.99 27.97 ± 6.1 0.19 ± 0.38 69.46 ± 2.0 Fig. 4 shows the dependencies of the wastewater optical density being purified and the biofloculating effect as a function of operating time. An analysis of the presented dependencies shows that a significant decrease of the optical density index occurs almost immediately, in the first 10–30 minutes from the bioflocculation starting point, but the optimal settling time is the time interval of about 100 minutes. Fig. 4. Optical density and flocculating effect as a function of operating time Рис. 4. Оптическая плотность и флокуляционный эффект в зависимости от времени Conclusions The extraction method affects not only the efficiency of EPS extraction, but also the possibility of EPS application for the purification of certain types of sewage. The (NH 2 ) 2 CO method has the highest extraction efficiency (15.2 ± 4.37 %), but produces EPS not capable of performing fish processing wastewater treatment. The EDTA and CH 3 COOH methods are preferable for the production of effective wastewater bioflocculants for fish processing plants, although their extraction efficiency is slightly lower – 13.08 ± 3.57 and 5.22 ± 2.79 % respectively. The use of EPS obtained by the EDTA method leads to the significant reduction of total suspended solids and optical density; EPS got with the CH 3 COOH method reduce the content of dissolved solids and optical density. Probably, it is promising to create a complex of bioflocculants that has the capabilities of EPS of the EDTA and CH 3 COOH methods to increase the efficiency of fish processing wastewater treatment in relation to all the indicators studied. Indicators of efficiency of wastewater purification have increased with increasing the biofloсculant dose. Thus, with increase in the dose of bioflocculant obtained due to the EDTA method from 1 g/l to 10 g/l, the removal of suspended matter has increased from 25.78 ± 3.45 to 74.21 ± 6.8 %, and the flocculation effect – from 27.97 ± 6.1 to 69.46 ± 2.0 %. 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0 5 10 20 30 40 50 60 80 100 Flocculating effect Optical density, 1/cm Time, min Optical density by EPS of method EDTA Optical density by EPS of method СH3COOH Flocculating effect by EPS of method EDTA Flocculating effect by EPS of method СН3СООН