The use of membrane technologies for calcium chloride recovery

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F28676092%3A_____%2F24%3AN0000024" target="_blank" >RIV/28676092:_____/24:N0000024 - isvavai.cz</a>

Výsledek na webu

<a href="https://euromembrane2024.cz/euromembrane-2024-book-of-abstracts/" target="_blank" >https://euromembrane2024.cz/euromembrane-2024-book-of-abstracts/</a>

DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

The use of membrane technologies for calcium chloride recovery

Popis výsledku v původním jazyce

Industry consumes a lot of water, and many sectors have specific requirements for water quality (e.g. food industry, paper industry, etc.). Almost all treatments of these waters and wastewater treatment from these industries create streams that end up at the wastewater treatment plant (WWTP) with subsequent discharge into surface recipients. In recent years, the demand for wastewater recycling technologies increased mainly due to tightening the discharge limits for industrial wastewater. Thus, common wastewater treatment (WWT) project requirements lead to processes with minimal or zero liquid discharge. This work aims at the use of WWT membrane technologies to obtain water with high recovery with minimal liquid discharge and salt recovery by processing the effluent from industrial WWTP.WWT technologies used in this work contained pre-treatment technologies (lamellar settler, sand filtration and ultrafiltration) and electrodialysis in two stages. The whole technology was arranged into two containers, providing flexibility and easy transport to different locations. The first container included a lamellar settling tank, sand filtration and ultrafiltration (UF). The second container included a pilot electrodialysis unit EDR-Y. A two-circuit pilot scale electrodialysis module equipped with either standard heterogeneous membranes or thin heterogeneous membranes RALEX® was used. The first stage of electrodialysis was used as a concentration step, and the second stage was used to demineralise the solution to fulfil the discharge limits. The UF permeate was used as a feed solution for the first ED stage. Its TDS content was approximately 25 g·L–1 and contained high CaCl2 concentration - Ca concentration ca 9 g·L–1 and Cl– concentration ca 15 g·L–1. The second ED stage processed a diluate from the first ED stage containing ca approximately 11 g·L–1 TDS. The presented pilot-scale two-container WWT technology processed the effluent from the industrial WWTP. The solution was processed in the first container to reduce the turbidity and suspended solid particles prior to the electrodialysis process step. The goal of the first stage of electrodialysis (ED1) was to achieve maximum concentration of the concentrate, mainly CaCl2. The ED concentrate from the ED1 reached a conductivity of 160 mS·cm–1 with a CaCl2 concentration of 124 g·kg–1 and a TDS of 140 g·L–1. The CaCl2 purity was over 95 %. It is planned to further process the concentrate from the ED1 stage in an evaporator to form a solid salt. The by-product of the ED1 - diluate with the conductivity of 20 mS·cm–1, containing ca 10 g·kg–1 of CaCl2, was further processed in the second stage of electrodialysis (ED2). A concentrate with a conductivity of 74 mS·cm–1 and TDS of 44 g·l–1 was obtained from ED2, while a mixture of NaCl and CaCl2 forms 99 % of these salts. This concentrate could be returned to the ED1 and mixed with raw material to ensure the MLD process. The diluate from the ED2 can be further used in other processes (raw or after additional RO) or disposed of, as it also meets stricter standards for discharge into the sewer.

Název v anglickém jazyce

The use of membrane technologies for calcium chloride recovery

Popis výsledku anglicky

Industry consumes a lot of water, and many sectors have specific requirements for water quality (e.g. food industry, paper industry, etc.). Almost all treatments of these waters and wastewater treatment from these industries create streams that end up at the wastewater treatment plant (WWTP) with subsequent discharge into surface recipients. In recent years, the demand for wastewater recycling technologies increased mainly due to tightening the discharge limits for industrial wastewater. Thus, common wastewater treatment (WWT) project requirements lead to processes with minimal or zero liquid discharge. This work aims at the use of WWT membrane technologies to obtain water with high recovery with minimal liquid discharge and salt recovery by processing the effluent from industrial WWTP.WWT technologies used in this work contained pre-treatment technologies (lamellar settler, sand filtration and ultrafiltration) and electrodialysis in two stages. The whole technology was arranged into two containers, providing flexibility and easy transport to different locations. The first container included a lamellar settling tank, sand filtration and ultrafiltration (UF). The second container included a pilot electrodialysis unit EDR-Y. A two-circuit pilot scale electrodialysis module equipped with either standard heterogeneous membranes or thin heterogeneous membranes RALEX® was used. The first stage of electrodialysis was used as a concentration step, and the second stage was used to demineralise the solution to fulfil the discharge limits. The UF permeate was used as a feed solution for the first ED stage. Its TDS content was approximately 25 g·L–1 and contained high CaCl2 concentration - Ca concentration ca 9 g·L–1 and Cl– concentration ca 15 g·L–1. The second ED stage processed a diluate from the first ED stage containing ca approximately 11 g·L–1 TDS. The presented pilot-scale two-container WWT technology processed the effluent from the industrial WWTP. The solution was processed in the first container to reduce the turbidity and suspended solid particles prior to the electrodialysis process step. The goal of the first stage of electrodialysis (ED1) was to achieve maximum concentration of the concentrate, mainly CaCl2. The ED concentrate from the ED1 reached a conductivity of 160 mS·cm–1 with a CaCl2 concentration of 124 g·kg–1 and a TDS of 140 g·L–1. The CaCl2 purity was over 95 %. It is planned to further process the concentrate from the ED1 stage in an evaporator to form a solid salt. The by-product of the ED1 - diluate with the conductivity of 20 mS·cm–1, containing ca 10 g·kg–1 of CaCl2, was further processed in the second stage of electrodialysis (ED2). A concentrate with a conductivity of 74 mS·cm–1 and TDS of 44 g·l–1 was obtained from ED2, while a mixture of NaCl and CaCl2 forms 99 % of these salts. This concentrate could be returned to the ED1 and mixed with raw material to ensure the MLD process. The diluate from the ED2 can be further used in other processes (raw or after additional RO) or disposed of, as it also meets stricter standards for discharge into the sewer.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

20402 - Chemical process engineering

Projekt

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů