Contents lists available at ScienceDirect Bioresource Technology journal homepage: www.elsevier.com/locate/biortech Performance evaluation of gaseous emissions and Zn speciation during Zn- rich antibiotic manufacturing wastes and pig manure composting Junchao Zhao, Xining Sun, Mukesh Kumar Awasthi, Quan Wang, Xiuna Ren, Ronghua Li, Hongyu Chen, Meijing Wang, Tao Liu, Zengqiang Zhang ⁎ College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, PR China ARTICLE INFO Keywords: Zn-rich antibiotic manufacturing wastes Pig manure Composting Zinc speciation Gaseous emissions ABSTRACT In this study, the co-composting performance of Zn-rich antibiotic manufacturing wastes (AMW) and pig manure (PM) was evaluated. Four treatments, representing 2.5%, 5%, 10% and 20% of AMW (of PM dry weight) and control without AMW, were established during composting. Results suggested that the temperature, pH, elec- trical conductivity, NH 4 + -N and germination index in end product met the maturity and sanitation requirement. More than 99% of residual antibiotic was removed. Compared with PM composting alone, the cumulative CH 4 and N 2 O emissions in AMW composting increased by 13.46–79.00% and 10.78–65.12%, respectively. While the higher mixing ratios of AMW (10% and 20%) presented a negative impact on composing by inhibiting organic matter (OM) degradation and higher NH 3 emissions. The AMW had highly bioavailable Zn, but the exchangeable faction of Zn significantly decreased with the composting progress. 1. Introduction Nowadays, China has become one of the largest antibiotic producers and exporters in all over the world, which accounts for 20–30% of the world’s production of antibiotic manufacturing wastes (AMW) in the early 2008 (Wu et al., 2011). AMW are kinds of industrial fermentation bio-wastes which contain considerable quantity of nutritional sub- stances (i.e., starch, maize slurry, protein and amino acids) (Xiao et al., 2015; Yang et al., 2016), and also included high levels of residual an- tibiotics and heavy metals (zinc and copper, etc) (Ding et al., 2014; Zhang et al., 2018a). This AMW were once transported to the en- vironment without proper disposing, might increase the risk of gen- eration and spread of antibiotic resistance genes in food chain (Zhang et al., 2015). Therefore, AMW were classified as one of the hazardous solid wastes by the Chinese government (The People’s Republic of China Ministry of Environmental Protection and National Development and Reform Commission, 2008). Additionally, the huge quantity of PM generation (∼490 million tons in 2015) was also attracted more and more attention to Chinese government due to their high nutritional value and resource loss (NBSC, 2016; Li et al., 2012). But its direct application caused some serious environmental issue such as soil and water pollutions and the obnoxious odor emission (Jensen et al., 2018; Orzi et al., 2018; Wang et al., 2018). Hence, it is necessary to introduce a practical and economical feasible technology for degradable organic waste management (Li et al., 2018). For the aim of nutrients recycling, composting is a biological process that reduce the environmental risk of AMW and PM as well as promotes the conversion of stable and hygienic end product for land utilization (Zhang et al., 2015; Zhang et al., 2018a; Yang et al., 2016). Residue antibiotics such as β-lactam, aminoglycosides, tetracycline, sulfona- mide and macrolide in AMW and other organic solid wastes could be effectively removed during composting (Liu et al., 2017; Selvam et al., 2012; Yang et al., 2016; Zhang et al., 2018a). Zhang et al. (2015) re- ported that about 99.95% of penicillin was decreased within first 10 days in penicillin fermentation fungi residue and PM co-composting. Similarly, Ho et al. (2013) identified that the removal rate of ery- thromycin during broiler manure composting was approximately 100%. Composting is regarded as a feasible approach to recycling organic waste, but gaseous emissions during the composting were also ad- versely affected to the surrounding environment (Awasthi et al., 2016; Wang et al., 2013a,b). CH 4 and N 2 O have 25 and 296 times higher global warming potential than CO 2 , which are highly responsible for the atmospheric pollution (IPCC, 2015). Additionally, ammonia volatilization during composting process not only causes the nitrogen loss, but also has the potential risk of global warming (Awasthi et al., 2018; Santos et al., 2017; Wang et al., 2016b). Thus, gaseous emissions are one of the major challenges that cannot be ignored during composting (Awasthi et al., 2016, 2018; Santos et al., https://doi.org/10.1016/j.biortech.2018.07.088 Received 10 May 2018; Received in revised form 16 July 2018; Accepted 18 July 2018 ⁎ Corresponding author at: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China. E-mail address: zhangzq58@126.com (Z. Zhang). Bioresource Technology 267 (2018) 688–695 Available online 19 July 2018 0960-8524/ © 2018 Elsevier Ltd. All rights reserved. T