New Technologies for Electro-Desalination Wastewater Treatment
Currently, the main challenges in treating electro-desalination wastewater are as follows:
1. High Oil Content: Under normal conditions, electro-desalination wastewater contains oil ranging from 200 mg/L to 10,000 mg/L. In abnormal cases, oil content can exceed 10% and even reach up to 50%, posing a significant challenge to treatment.
2. Complex Crude Oil Sources and Properties: Crude oil comes from diverse sources, including multiple international oil fields. The types of crude oil are varied and compositionally complex, including light oil, condensate, heavy oil, and various non-hydrocarbon compounds.
3. Severe Emulsification: During crude oil extraction, chemical additives such as wax inhibitors, anti-wax agents, and demulsifiers are used, which degrade the crude oil quality and cause severe emulsification. The emulsion does not separate even after long periods of settling.
To address the above challenges, Shenzhen Clear Science & Technology Co., Ltd (SINOKLE), after years of research and field testing, has developed a new, highly efficient electro-desalination wastewater treatment process. The process first cools the oil-containing wastewater separated from electro-desalination units through heat exchange, then sends it to a high-efficiency oil-water separator for preliminary separation. In the separator, floating oil, dispersed oil, and part of the emulsified oil rapidly gather and coalesce into larger oil masses, which are then separated from the wastewater and discharged into an oil collection tank.
The wastewater still contains a significant amount of emulsified oil after the preliminary oil-water separation. It is then further treated using a high-efficiency Cyclonic Dissolved-gas Flotation Unit (CDFU). In the CDFU, the emulsified oil is captured by ultrafine air bubbles and continuously aggregated and coalesced under the cyclonic effect, breaking the emulsion to form oil masses, which are ultimately separated from the wastewater. The treated wastewater is then sent to the wastewater treatment plant network for further processing.
Scheme of the New Electro-Desalination Wastewater Treatment Process
The advantage of this new electro-desalination wastewater treatment solution lies in its departure from the traditional separation method that relies solely on oil-water density differences. Instead, it uses density differences among gas-water and oil-gas-water phases for separation, making the oil removal performance largely independent of the oil’s density and greatly improving separation efficiency. At the same time, the process employs advanced equipment such as high-efficiency coalescing/plate-press oil separators and compact, high-efficiency dissolved-air flotation units, offering high separation efficiency, strong impact resistance, low risk of clogging, and low energy consumption.
Electro-Desalination Wastewater Treatment Results (Left: Effluent, Right: Influent)
The entire treatment process offers high oil removal efficiency, requires low pressure (<0.15 MPa), consumes little energy, and operates stably and reliably. Even when the oil content in electro-desalination wastewater fluctuates dramatically, the process ensures that the treated water consistently meets the requirements for discharge into the wastewater treatment plant (oil content <100 mg/L).
Additionally, the new process features a high degree of automation, and fully enclosed operation. This not only reduces labor costs for operation and maintenance but also prevents the release of hazardous gases, minimizing risks to employees and the surrounding environment. At the same time, the equipment is reasonably priced and cost-effective, delivering significant economic and social benefits to enterprises.
