Centrifugal extractors for treating phenol-containing wastewater from chemical active pharmaceutical ingredients

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The sources of wastewater from chemical active pharmaceutical ingredients include process water used in the workshops, wastewater generated from cleaning equipment and pipelines, wastewater resulting from the solid-liquid separation steps in drug extraction or purification processes, water used for cleaning by workshop staff, and domestic wastewater from the factory premises. At the same time, sources of wastewater also include boiler drainage and discharged cooling water. In industrial wastewater, the components of all materials used in the production process are present, including drug intermediates, unknown substances, and target substances (residual products); it also contains new products formed when the wastewater is in mixed aerobic and anaerobic conditions. In the **special survey on water use, the compliance status of pharmaceutical companies is concerning: only a small number of these companies are able to meet the new standards for wastewater discharge in the pharmaceutical industry; the compliance rates for pharmaceutical wastewater from chemical synthesis, fermentation, and formulation processes are 9%, 12%, and 30%, respectively. According to further investigations, most municipal wastewater treatment plants in the country require that the COD level of wastewater from the pharmaceutical industry be ≤300 mg/L. Even with this requirement, some chemical synthesis and fermentation-based pharmaceutical companies still fail to meet it; 46% of those in the chemical synthesis sector and 16% of those in the fermentation sector fall short of these standards. Another reason why treating wastewater from the production of chemical active pharmaceutical ingredients is difficult is that companies often adjust their products and production volumes in response to market demands. The pollution load generated by these new production conditions conflicts with the biological systems and operating parameters of the existing treatment facilities, often resulting in non-compliance with standards for a certain period of time. Wastewater from chemical active pharmaceutical ingredients generally has a complex composition, high pollutant concentrations, and contains large amounts of toxic and harmful substances, bioinhibitors (including certain concentrations of antibiotics), recalcitrant substances, etc. It is colored and odorous, has a high content of suspended solids, and tends to form foam. Characteristics of wastewater quality in chemical active pharmaceutical ingredients: The wastewater from chemical active pharmaceutical ingredients mainly contains various natural organic substances, with the main components being sugars, organic acids, glycosides, anthraquinones, lignin, alkaloids, tannins, proteins, starches, and their hydrolysis products. Pharmaceutical wastewater contains many biodegradably difficult cyclic compounds, heterocyclic compounds, organophosphorus substances, organochlorine compounds, phenols, and unsaturated fatty compounds. The removal or conversion of these substances is an important approach for removing COD from pharmaceutical wastewater. The main pollutant in wastewater from traditional Chinese medicine production is the high concentration of organic waste. In the traditional Chinese medicine manufacturing industry, due to the differences in various medicinal substances and production processes involved in drug production, there are significant variations in both the quality and quantity of the wastewater generated. Moreover, because of the short product replacement cycles, the quality and quantity of wastewater fluctuate frequently as products change, resulting in great instability. Another characteristic of traditional Chinese medicine wastewater is its high concentration of organic pollutants. It contains a high amount of suspended solids, as well as organic substances such as lignin that are light in density and difficult to precipitate. The wastewater also has a high color intensity. Its biodegradability is relatively good; it is usually discharged intermittently, and its composition is complex with significant variations in water quality and volume. The significance of using centrifugal extractors to treat phenol-containing wastewater in chemical active pharmaceutical ingredients: Due to their advantages such as small footprint, high processing capacity, and good sealing performance, centrifugal extractors can be designed with different structures depending on the separation requirements, processing capacity, and system characteristics. This allows for significant savings in extraction agent costs, with a phenol removal rate of over 95%. Currently, domestic enterprises discharge approximately 40 billion tons of industrial wastewater per year, of which phenol-containing industrial wastewater accounts for around 0.5%, amounting to about 2 billion tons. According to market research, it is estimated that around 30% of the total amount of phenol-containing industrial wastewater generated in China can be dephenolized using centrifugal extractors, which means that over a thousand such extractors would be needed in total.