Treatment of sulphate wastewater by freeze desalination

Zikalala, Nomvuselelo N.; Maree, J. P.; Zvinowanda, Caliphs; Akinwekomi, Vhahangwele; Mtombeni, T.; Mpenyana-Monyatsi, Lizzy

doi:10.5004/dwt.2017.20927

Cited by 9 publications

(7 citation statements)

References 10 publications

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“…Similarly, the volumes of brine created are significantly reduced, which will aid in the unsustainable disposal problems currently faced. Hybrid FC processes are also suggested to have the lowest energy consumption when compared to conventional saline waste stream treatment options (Zikalalaa et al, 2017). Obviously any technology cannot guaranty a complete and perfect solution without limitation (Table 4).…”

Section: Advantages and Disadvantages Of The Freeze Concentration Tec...mentioning

confidence: 99%

Sustainable nutrient recovery from animal manure: A review of current best practice technology and the potential for freeze concentration

Dadrasnia

Muñoz

Hernández

et al. 2021

Journal of Cleaner Production

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Section: Advantages and Disadvantages Of The Freeze Concentration Tec...mentioning

confidence: 99%

Sustainable nutrient recovery from animal manure: A review of current best practice technology and the potential for freeze concentration

Dadrasnia

Muñoz

Hernández

et al. 2021

Journal of Cleaner Production

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“…Freeze desalination is an available technology for desalinating saline brine at better energy consumption compared to distillation and evaporation (333kJ/kg for freezing versus 2500 kJ/kg for evaporation [13]. Other benefits of freeze crystallization include: (i) no pre-treatment and (ii) less prone to corrosion and metallurgical challenges [14].…”

Section: ) Freeze Crystallization As An Alternative To Evaporationmentioning

confidence: 99%

“…Freeze crystallization further involves the recovery of ice of high purity and good salt recovery. Rapid nucleation and formation of crystals results with impure ice crystals due to the faster rate of growth [13]. The overall principle of rejection of salt as water changes phase to solid gave existence of freeze desalination which is the alternative technique for recovery of salt and water in the form of ice.…”

Section: ) Freeze Crystallization As An Alternative To Evaporationmentioning

confidence: 99%

“…When heat is removed from brine, reaching its freezing point, ice crystals start to form, their crystallization excludes the unwanted impurities and the physical chemistry of the ice is similar to pure water [16]. It should be noted that the theoretical energy required to drive an evaporation process is seven times more than that of freezing [13]. The heat of fusion of ice is 333 kJ/kg compared to the heat of evaporation of water which is 2 260 kJ/kg.…”

Section: Freeze Crystallizationmentioning

confidence: 99%

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Treatment of Flue Gas Desulphurisation Effluent with Freeze Crystallization

2022

35th JOHANNESBURG International Conference on “Chemical, Biological and Environmental Engineering” (ICCBEE-22) Nov. 28-29, 2022

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Kusile was the first power station of Eskom to implement a wet flue gas desulfurization system for the control of SO2 and other greenhouse gasses. The waste water from the flue gas desulfurization (FGD) plant contained a high total dissolved solids (TDS) concentration of 50 000 mg/L due to: (i) absorption of SO2, chloride and boron from the coal to the FGD waste water, (ii) dissolution of sodium, potassium, magnesium, manganese and calcium form the limestone when reacted with the acid gasses from the combustion chamber. A large portion of the calcium sulphate in solution precipitated as gypsum due to its limited solubility.The study focused on disposal, electrical and chemical cost of three FGD waste water management methods. It was found that the cost for a 4 800MW plant will amount to R9.7 million per month for disposal at a toxic waste disposal site, R11.41 million per month when pre-treated with lime/sodium carbonate followed by evaporation and R0.96 million per month when treated with Freeze crystallization. Freeze crystallization was found to be the most cost effective as it did not need chemical pre-treatment and it consumes less energy than evaporation (330kJ/kg in the case of freeze versus 2 260kJ/kg in the case of evaporation). Energy usage was found to be 100 kWh/kg ice. The TDS of the Feed amounted to 50 000 mg/L compared to less than 3 000 mg/L in the melted ice.

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“…These raw mineral sources contain multiple components (e.g., Na + , K + , Ca 2+ , Mg 2+ , Cl – , SO 4 2– , Br – ), and a suitable crystallization method, e.g., evaporative crystallization, cooling crystallization, and reactive crystallization, is often used to isolate individual salts from the solution. Aqueous solutions containing calcium, sodium, potassium, magnesium, sulfate, and chloride as the significant ions are generated from seawater reverse osmosis plants, industrial effluents, , and common salt-harvesting activities. − The solubility curve for each salt significantly influences the choice of the crystallization process, that is, the way to achieve supersaturation. Earlier studies have shown the application of different crystallization methods including freeze crystallization, ,, cooling crystallization, and antisolvent crystallization for the recovery of sodium sulfate from aqueous solutions.…”

Section: Introductionmentioning

confidence: 99%

Process Design Framework for Inorganic Salt Recovery Using Antisolvent Crystallization (ASC)

Sahu,

Gao,

Bhatti

et al. 2023

ACS Sustainable Chem. Eng.

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Antisolvent crystallization (ASC) can be an alternative separation strategy over evaporative or cooling crystallization for selective salt recovery from aqueous salt mixtures. While a large amount of literature has been focused on phase equilibrium data generation, the implication of phase behavior on antisolvent selection and process performance has not been adequately discussed. This work aims to develop a methodical framework combining solubility behavior, phase balance, antisolvent selection, and solvent recovery to design sustainable ASC processes for the selective isolation of salts from aqueous solutions. The methodology was tested for the application of ASC to separate sodium sulfate from sodium chloride, as those mixtures generate as saline effluent from salt-harvesting activities. Technoeconomic feasibility, sustainability, and life cycle analysis of the proposed ASC process were performed to establish its potential toward commercialization. Several environmental impact categories were analyzed on the ASC process with antisolvent recovery, direct disposal, and incineration, comparing their performance and highlighting the overall sustainability. The presented process design framework will guide early feasibility studies considering ASC for inorganic salt separation and purification from saline effluents.

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Treatment of sulphate wastewater by freeze desalination

Cited by 9 publications

References 10 publications

Sustainable nutrient recovery from animal manure: A review of current best practice technology and the potential for freeze concentration

Sustainable nutrient recovery from animal manure: A review of current best practice technology and the potential for freeze concentration

Treatment of Flue Gas Desulphurisation Effluent with Freeze Crystallization

Process Design Framework for Inorganic Salt Recovery Using Antisolvent Crystallization (ASC)

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