Application Of Hydrothermal Carbonization Technology In The Recycling Of Macrolide Antibiotic Pharmaceutical Waste Liquid

In China,the production and consumption of antibiotics are in a large scale,and the export volume of antibiotics accounts for a large share in the international market.Wastewater discharge from pharmaceutical plants is one of the main sources of antibiotics in the environment.The water quality of pharmaceutical wastewater is complex,the residual antibiotics in wastewater can be exposed to the environment and cause potential damage to ecosystems and human health through the food chain.Widely used macrolide antibiotics have highly residual levels in traditional activated sludge systems,which are difficult to biodegrade.How to realize the harmless and resource treatment of macrolide antibiotic pharmaceutical wastewater has become an urgent problem to be solved.In this paper,the hydrothermal carbonization technology was applied to the treatment of macrolide antibiotic pharmaceutical wastewater,and the macrolide antibiotic pharmaceutical wastewater was effectively treated by one-step low-temperature efficient method.The main results are as follows:(1)The reaction was carried out at 160?,180?,200? for 2h,4h,8h,the antibiotic wastewater achieved good solid-liquid separation effect.In the liquid,the COD degradation rate reached 68.3 %,the content of ammonia nitrogen increased by 73.3%,and the total nitrogen content decreased by 19.7%.Moreover,the surface of the solid product is in the form of granular,rod-shaped and pore-like.The recovery rate is as high as 97% at 160?.The solid product obtained at 180? has the best drying performance,the aliphatic structure in the product increased,the hydroxyl group and amino group decreased.Oxygen-containing functional groups such as carboxyl groups,carbonyl groups and ester groups are continuously decreased with increasing hydrothermal temperature.The content of inorganic-N,protein-N and pyrrole-N are continuously decreased,with pyridine-N and quaternary-N increased.(2)We chose two kinds of macrolide antibiotics,erythromycin and tylosin phosphate.After hydrothermal treatment at 180? for 8h,the degradation rate of erythromycin reached more than 85%,and the degradation rate was positively correlated with hydrothermal temperature and time.The tylosin phosphate was hydrothermally treated at 160? for 2h,the degradation rate was over 99%.(3)The combustion performance of the solid product as a solid fuel for biomass was evaluated.The calorific value of the hydrothermal carbonized solid product was similar to lignite,reaching 23.3 MJ/Kg,which was 43.8% higher than the original.The ignition temperature was lower,the flammability index was increased,and the post-burning rate upped to 85.18%.The content of alkali metal K and Na decreased to 0%,and the basic oxide index was lowered from 0.78 to 0.17.The contents of Cl and S were significantly reduced after hydrothermal treatment,which improved fuel combustion characteristics and reduced the risk of equipment corrosion and slagging.At the same time,the effects of catalysts such as iron salts and calcium salts on the combustion characteristics of solid products were also studied.It was found that the ignitability index of the solid product with ferric chloride as a catalyst was 25 times higher than that of the reference substance,the post-burning rate was about 100.53%,and the comprehensive combustion characteristic index was the largest.