DOI 10.35776/VST.2022.05.05
UDC 628.3(628.345.1)
Arduanova Anna, Glushankova Irina
Choosing coagulants and flocculants for the local treatment of wastewater of pulp and paper industry
Summary
The results of studies on removing lignosulfonates, suspended solids and sulfur-containing compounds from pulp and paper industry wastewater by chemical treatment are presented. As chemicals the following coagulants were studied: alumina, ferrous sulfate, iron (III) sulfate, and flocculants Praestol and RusFloc, that differ in charge, molar mass, and ionic activity. In the course of the experiment, it was found that the most effective removal of lignosulfonates and sulfur-containing compounds from wastewater proceeded in the presence of ferrous sulfate coagulant and Praestol 810 cationic flocculant. In this case, easily settling thickened sludge is formed and the efficiency of removing sulfide ion is 92%, the color of water decreases 3–4 times. The optimal dose of the coagulant as metal ion is 300 mg/dm3, the dose of the flocculant is 1.5 mg/dm3. Comparison of the activity of RusFloc cationic flocculants in terms of settling time, sludge layer thickness, clarified water COD, showed that the use of RusFloc 504 cationic flocculant is most effective for the coagulation of wastewater containing lignosulfonates. The optimal dose of the chemical was 5 mg/dm3. Studies on wastewater treatment by coagulation-flocculation in the presence of ferrous sulfate coagulant and RusFloc 504 flocculant at pH 8.5 showed 70% reduction of COD of organic compounds – lignosulfonates, and more than 90% color. On the basis of the conducted studies, the choice of conditions and effective chemicals for the local treatment of pulp and paper industry wastewater is substantiated.
Key words
coagulation , pulp and paper industry , flocculation , optimal dosage of chemical , pulp production , lignosulfonates , sulfide-ion
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UDC 628.321
Riabchikov Boris, Larionov S. Iu., Panteleev Aleksei, Shilov Mikhail
The study of enhanced water coagulation with the use of microsand
Summary
The results of the analysis of the present day advanced water coagulation equipment are presented. The results of the study showed that using the systems with sludge recycling and microsand addition was the most efficient solution. Because of the lack of reliable data on the efficiency of the given equipment, operational mode and chemical consumption, experimental units were designed that provided for testing the required modes and significant improving the process. Using sand from a packed column equipped with airlift for washing produced good results. Sand loss was less than 1%. In the process of the experimental studies it was shown that the effect of fast precipitation in the clarifier at high linear water flow rate was possible. However, the use of static chemical mixing systems does not provide for the sustainable unit operation with changing parameters – flow rate, stock solution concentration, and temperature. For that reason the unit was upgraded following Actiflo option with the use of mechanical mixers for mixing with chemicals and sand, however, with sand and sludge separation in the plate column equipped with a pulsation system to improve the wash efficiency. The designed flowsheet of sludge separation into microsand and sludge with the help of a packed column showed significant advantages compared to the system with hydrocyclones. On the basis of the obtained data terms of reference for designing a pilot unit were developed.
Key words
potable water , hydrocyclone , coagulation , microsand , flocculation , static mixer , wash column
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UDC 628.316.13:628.345.4
DOI 10.35776/VST.2023.02.03
Eremeev Dmitrii, Gruzdev Sergei
Clarification of recycled water of gas cleaning of a blast furnace using a water-dispersible flocculant
Summary
The results of laboratory testing of choosing the optimal flocculant for clarification of recycled water of blast furnace gas cleaning are presented. Laboratory testing was carried out according to the standard method of sedimentation (clarification) in glasses. It has been shown that the use of ATE 12520 liquid water-dispersible flocculant provides for the successful removal of suspended solids and turbidity from gas cleaning recycled water. The proposed chemical treatment program was recommended for commercial testing of the clarification system of gas cleaning recycled water of a blast furnace at one of the ironworks in Russia. The ATE 12520 flocculant dosage range recommended for testing (as commercial chemical) in terms of wastewater supplied to the circular sedimentation tank is 0.3–0.5 g/m3.
Ключевые слова
recycling water , flocculation , gas cleaning , wastewater clarification , flocculant (powdered, emulsive, water-dispersible) , liquid flocculant inversion
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DOI 10.35776/VST.2021.11.07
UDC 628.33:622.5
Kasperovich Viktoriia
Choosing the chemicals and advanced filter media for enhancing the process of mine water purification
Summary
Currently, the construction of facilities for the purification of mine waters is one of the important measures aimed at preserving surface watercourses and water reservoirs. The amount of mine water discharged into surface water bodies can be reduced by reusing it for complex dedusting in mines, process water supply and other most water-intensive technological processes. One of the effective ways of removing suspended solids and heavy metals from mine water is chemical treatment with high-molecular flocculants that provide for reducing the consumption of inorganic coagulants and enhancing the process of suspended solids and heavy metals precipitation. Pretreatment of mine water upstream contact clarifiers can significantly increase the capacity of existing treatment facilities, stabilize their operation in case of fluctuations in the quality composition and temperature of mine water, and reduce the load on the subsequent stages of filtration in rapid filters. The results of experimental laboratory studies of trial coagulation and flocculation with subsequent filtration in rapid filters using Orefilter B catalytic filtering media, AS sorbent and Extrasorb sorption media, as well as removing (stripping) ammonia from mine water are presented.
Key words
filtration , coagulation , heavy metals , flocculation , mine water purification , mineral compounds , ammonia air-stripping , Orefilter В catalytic media , sorption media
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UDC 628.321
Gaid Kader, Sauvignet Philippe, Buisson Hervé
The combination Actiflo – MF/UF membrane: an efficient solution for surface waters
Summary
Process schemes of surface water treatment with membrane filtration in most cases at the final stage require advanced clarification technologies that provide for efficient removing color and high concentrations of organic and suspended solids from raw water. Therefore, «Actiflo® – ultra- and microfiltration» process scheme is the optimal solution for drinking water purification. The results of pilot tests of «Actiflo® – ultra- and microfiltration» process scheme are presented. The experience of operating the plants using this scheme is generalized.
Key words
coagulation , ultrafiltration , microfiltration , surface water , microsand , flocculation , pretreatment , Actiflo® process scheme
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UDC 628.16.052.2
Potapov V. V., Brovkin A. E.
Improving natural water purification with the use of new generation chemicals
Summary
The main aspects of natural water purification with coagulation are considered. The data on the composition of the surface public water supply sources in the area of Petropavlovsk-Kamchatsky are presented. The average molecular weight of humus substances present in natural waters is determined. The results of experimental studies of using new generation coagulants and flocculants in natural water purification at the water treatment facilities of MUE «Petropavlovsk Vodokanal» are presented. The action of coagulants: aluminium sulfate, aluminium hydroxychloride and aluminium oxychloride was studied. It was stated that the maximum efficiency of color removal from natural water in the Petropavlovsk-Kamchatsky environment is provided by the use of aluminium sulfate and aluminium hydroxychloride; whereas the use of aluminium oxychloride was less efficient. The efficiency of turbidity removal when using all the three coagulants was high – 70–100%. Praestol 650 TR and Praestol 2515 TR flocculants at mutual dose testing improve the efficiency of color removal: Praestol 2515 TR – from 49–66 to 63–100%. The use of flocculants provided for improving the floc formation rate, floc size, floc sedimentation rate and sludge volume. To introduce the new advanced coagulant at the water treatment plant the coagulation process testing with the use of aluminium sulfate in combination with the flocculant is required. To eliminate possible formation of problem chlororganics before the coagulant takes effect and humus settles special attention shall be paid to the sodium hypochlorite injection point when coagulating high-colored water.
Key words
turbidity , chromaticity , coagulation , flocculation , natural water , flocculation , water purification efficiency
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