Flocculation-based methods of microalgae removal from the eutrophic pond enrichment culture

The method of flocculation of biomass from the water depth to the bottom can be applied in case of local algae blooms. In our research, the combined application of FeCl3 and Polyethyleneoxide-based cationic flocculant was applied for the first time for the harvesting of the enrichment culture obtained from the reservoir during eutrophication. The effects of coagulant (FeCl3·6H2O), various flocculants based on polyacrylamide (PAA), polyethylenoxide (PEO) and flocculated biomass as ballast agent, dosage and sedimental time on flocculation efficiency of harvesting enrichment culture obtained from Pond Chernoistochinsky during eutrophication have been studied. The results show that the flocculation efficiency achieved about 90% after 5 min of sedimentation when adding of coagulant and flocculant mixture (FeCl3 30 mg/L + PEO based Sibfloc-718 2.5 mg/L) or flocculant with ballast agent (FeCl3 30 mg/L + Sibfloc-718 2.5 mg/L + 1,7% flocculated biomass). PAA, PEO and FeCl3·6H2O did not demonstrate a sufficient flocculation capacity with enrichment culture containing different types of microalgae.

SEDIMENTATION ANALYSIS OF THE DISPERSED PHASE DURING TREATMENT OF PHENOLIC WASTEWATER OF COKE-CHEMICAL PRODUCTION BY GLAUCONITE

Kinetic regularities of adsorption treatment of phenolic wastewater with glauconite have been revealed. It was found that glauconite at a dose of 2 g/dm3 in combination with a 0.1% solution of cationic flocculant, which provides removal of resinous substances up to 94% for 10 min and phenols up to 20% during 20 min. As a result, the MPC of phenols and resinous substances was achieved at the stage of mechanical treatment of effluents, which are then fed for biochemical processing into aeratanks, which is 415 mg/dm³ and 25 mg/dm3, respectively. The dispersed composition of sediments after treatment of industrial wastewater with glauconite was studied. It was found that the particle radii of the polydisperse system "liquid waste – glauconite" in combination with cationic flocculant were the largest and reached r = 537 mkm, which is twice the maximum polydisperse systems "liquid waste – glauconite" and "liquid waste – glauconite" with an anionic flocculant. Sedimentation analysis showed that the sedimentation time of the sediment decreased from 17 min to 6 min in the system "liquid waste – glauconite" in combination with cationic flocculant and formed a precipitate of loose flakes, which settled quickly. The introduction of a flotation plant with a dosage of natural glauconite 2 g/dm3 in combination with a 0.1% solution of cationic flocculant at industrial treatment facilities is proposed. Engineering solutions will improve the quality of wastewater supplied for coke quenching and will make it possible to transport and dispose of sludge after waste treatment with glauconite, which is planned to be used as a raw material for the manufacture of pavements in asphalt plants.

Clarification of turbid water with the use of Praestol 650 flocculant

Рассмотрена эффективность самостоятельного применения катионного флокулянта Праестол 650 для очистки мутных вод в зависимости от мутности исходной воды и условий флокуляции. Показано, что приоритетными параметрами, определяющими эффективность самостоятельного применения катионного флокулянта Праестол 650 для очистки мутных природных вод, является интенсивность и длительность перемешивания в камере хлопьеобразования. При длительности не менее 20 минут и среднем градиенте скорости перемешивания G = 340 с-1 эффективность снижения мутности составляет 96% (конечная мутность 7 мг/л). Установлена 96%-ная эффективность неионного флокулянта с молекулярной массой 5–7 млн в неоптимальном режиме хлопьеобразования при длительности перемешивания 5 минут и G = 65 с-1. The efficiency of the individual use of the cationic flocculant Praestol 650 for the purification of turbid water is considered, depending on the turbidity of the source water and the conditions of flocculation. It is shown that the priority parameters that determine the effectiveness of the individual use of the cationic flocculant Praestol 650 for the purification of turbid natural water are the intensity and duration of mixing in the flocculation chamber. With a duration of at least 20 min and an average gradient of mixing rate G= 340 s-1, the efficiency of turbidity reduction is 96% (final turbidity being 7 mg/l). A 96% efficiency of the non-ionic flocculant with a molecular weight of 5–7 million was determined in a suboptimal flocculation mode with a mixing period of 5 min and G = 65 s-1.

Lithium carbonate sedimentation using flocculants with different ionic bases

Lithium has become a metal of enormous interest worldwide. The extensive use of rechargeable batteries for a range of applications has pushed for rapid growth in demand for lithium carbonate. This compound is produced by crystallization, by reaction with lithium chloride (in solution) and by adding sodium carbonate. Low sedimentation rates in the evaporation pools present a problem in the crystallization process. For this reason, in this work, mineral sedimentation tests were carried out with the use of two flocculant types with different ionic charges. The tests were carried out at a laboratory level using different dosages for each flocculant and measurements were performed to obtain the increase in the content of solids in the sediment. The anionic flocculant had better performance as compared to that of the cationic flocculant, increasing the sedimentation rate of lithium carbonate by up to 6.5. However, similar solids contents were obtained with the use of the cationic flocculant at 3.5 times lower dosage making it the flocculant of choice regarding the economic point of view.

Experimental and theoretical study of the flocculants mixing in water

The article discusses the process of high molecular weight flocculant particles dissolving in water during mechanical stirring. A procedure of mixer selection taking into account mixer geometry based on the Prandtl’s semi-empirical turbulence model was developed and described. It was found that the choice of the optimal rotation speed is related with the turbulent frictional stress generated by the impeller of the mixer. The results of experimental studies on the preparation of concentrated solutions of high molecular weight cationic flocculant MagnaflokМ 155 using various impeller types are shown. The efficiency of a conical mixer has been confirmed, which makes it possible prepare a flocculant solution 1.3 times faster due to the possibility of mixing at higher rotational speeds with lower power consumption