Occurrence, Fate And Environmental Risk Assessment Of Veterinary Antibiotics And Heavy Metals In Typical Swine Wastewater Treatment Processes, China

Swine breeding is an important part of livestock and poultry industry. Generally, pig farming generated large amounts of wastewater and manure. Swine wastewater own the properties of high COD, ammonia nitrogen, phosphate. In the process of pig husbandry, veterinary antibiotics and heavy metals are used in order to achieve the purposes of prevention and treatment of swine diseases and promoting growth, a considerable portion of veterinary antibiotics and heavy metals can not be absorbed by swine,30%～90% antibiotics were excreted in the form of the original drug or metabolites through the feces and urine, heavy metals were mostly excreted through faeces. The veterinary antibiotics and heavy metals discharged by the swine farm is an important way of environmental pollution. The wastewater treatment system in the swine farm is currently focused on the removal of COD, ammonia, nitrogen, phosphate, total phosphorus and other conventional indicators, but are not concerned about the removal of antibiotics and heavy metals in waste water. This paper chooses the typical farms to conduct a comprehensive investigation, collecting wastewater samples and solid samples including manure and organic fertilizer, after sample pretreatment, the antibiotics and heavy metals were detected and analyzed in the samples, then the residues of antibiotics and heavy metals in the wastewater and solid samples were investegated, and then assess the ecological risk.In this paper, the residues of antibiotics and heavy metals in the wastewater in the four typical wastewater treatment processes were investegated. Wastewater was collected from four different farms with four typical wastewater treatment processes, the results were as following, TCs, SAs, FQs are three types of commonly used antibiotics, the primary antibiotics were TCs, and SD of SAs, CIP of the FQs. The highest concentrations of CTC and DXC reach to 288.96 μg/Land 290.28μg/L, highest concentration of SD reach to 81.56 μg/L, the highest concentration of CIP and ENX reach to 190.07 μg/L and 476.41 μg/L. The ecological process shows a good removal efficiency of antibiotics. TCs and FQs were prone to adsorb on the SS, SAs prefer to migrate with the water and difficult to be biodegraded. In the raw wastewater, The total concentrations of Al, Fe, Zn, Mn and Cu were extremely high, reach to 18415.07 μg/L,13612.47 μg/L,12871.36 μg/L,4705.94 μg/L and 2463.72 μg/L, respectively. Adding Cu and Zn-rich feed additives in pig breeding process is the reason for the high concentration of Cu and Zn in the wastewater. Cu and Zn, were mainly discharged through manure, Cu and Zn is easily combine with the SS and show high distribution in the SS. The ecological Process show a good removal efficiency of heavy meatals. The biological treatment is ineffective for the removal of heavy metals and antibiotics.In this paper, the residues of antibiotics and heavy metals in the wastewater before and after upgrade of livestock and poultry breeding industry were invetegated. samples were collected from farms E, F and G, farms F and G in Zhejiang are in model citiy of the project "five water governance", the pig industry has been upgraded. The primary antibiotic in the raw wastewater of farms E and F are tetracyclines, the highest concentrations of CTC and DXC were as high as 3989.71 μg/L and 1133.17 μg/L, in the raw wastewater of farm G, SMT is the primary antibiotics, the concentration is 776.71 μg/L. After the industry upgraded, farm G owns the advanced farming methods and equipment, the medication is different to the farm E and F. The water consumption of farms F is less than that of farm E, which result in the high concentration of antibiotics in the raw wastewater. In the raw wastewater, the concentration of Al, Fe, Zn, Mn and Cu were reach to 28373.84 μg/L,46899.40 μg/L, 96843.59 μg/L,9310.04 μg/L,16276.46 μg/L, respectively. The ecological treatment process is effective to remove the heavy metals. After anaerobic digestion and biological treatment processes coupled with ecological treatment to form the combined process are commonly used, and the removal efficiency can be improved.Presume the manure and wastewater were irrigated farmland, and then make ecological risk assessment of antibiotics and heavy metals. No matter the final effluent or the digestion effluent, and manure or organic fertilizer were irrigated farmland for one year, the antibiotics brought into the farmland will cause ecological risk, and heavy metals brought into the farmland will not cause ecological risk.