Elimination of antibiotic resistance genes (ARGs) in animal manure from concentrated animal feeding operations by thermophilic composting has drawn increasing attention. This study investigated the effects of sawdust biochar, corn stover biochar and peanut hull biochar with three spiked levels on ARGs in swine manure during thermophilic composting. Thirteen ARGs corresponding to four classes of antibiotics (tetracyclines, sulfonamides, macrolides and quinolones) were determined in the composting piles. Results indicated that the ten tested composting groups became fully mature after 30-day thermophilic composting process. tetM, tetO and ermB were reduced in all tested groups; tetC and tetG, tetX, sul1, sul2, ermF, qnrD and aac(6')-Ib were mostly reduced under low level biochar addition but increased under higher level biochar addition; gyrA increased under medium biochar addition and reduced in other groups; oqxB remained comparatively stable throughout the composting process. The addition levels of spiked biochar are more important than types of spiked biochar on the removal of ARGs in the composting pile. The average removal rates of ARGs in the control group, low, medium and high level biochar addition groups were 0.24 logs, 0.52-0.72 logs, -0.52-0.18 logs and -0.19-0.21 logs, respectively. In summary, low level biochar addition could enhance the elimination of studied ARGs in swine manure during the composting process, while medium level biochar addition to the composting piles would increase the risk of ARGs' propagation. et al. Effects of different biochars on antibiotic resistance genes during swine manure thermophilic composting. Int J Agric & Biol Eng, 2018; 11(6): 166-171.

In recent years, the utilization of manure resources for livestock and poultry farming has attracted a widespread attention, and manure resources utilization models suitable for different regional characteristics have formed gradually. Among them, the production of organic fertilizer from animal manure is a vital utilization method. However, there are still some problems such as high production costs, difficult sales, and the unwillingness of farmers to use organic fertilizers which have affected the breeding cycle and the sustainability of manure treatment in livestock and poultry breeding. This article selected 371 organic fertilizer plants, related farms and farmers in China, focusing on the main links of the entire process of livestock manure-organic fertilizer-farm application, and studied the mode of animal manure collection by organic fertilizer plants. The costs of organic fertilizer production and farmland application were discussed. Moreover, suggestions were made for the promotion and implementation of large-scale organic fertilizers to make good utilization of manure resources in livestock and poultry farming.

A large amount of real complex wastewaters are generated every year, which leads to a great environmental burden. Various treatment technologies were deployed to remove the contaminants in the wastewaters. However, these actual wastewaters have not been sufficiently treated due to their complex properties, high-concentration organics, incomplete utilization of hard-biodegradable substrates, the high energy input required, etc. Recently, microbial electrolysis cells (MECs), a great potential technology, has emerged for various wastewater treatment, because not only do they demonstrate satisfactory performance during wastewater treatment, but they also generate renewable H 2 as a clean energy carrier. Unlike previous reviews, this review introduced the characteristics of every complicated wastewater, and focused on analyzing and summarizing MEC development for wastewater treatment. The performances of MECs were systematically reviewed in terms of organics removal, H 2 production, Columbic efficiency, and energy efficiency. MEC performances for treating actual complex wastewaters and producing H 2 can be optimized through operation parameters, electrode materials, catalyst materials, etc. In addition, the challenges and opportunities including complexity of wastewaters, instability of H 2 production, robust microorganisms, effect of membrane on two-chamber MEC, and integration of MEC with other treatment processes were deeply discussed. Except for the technical feasibility, both environmental feasibility and economic feasibility also need to meet social requirements. This review can indeed provide a basis for high-efficiency treatment and practical commercial applications of recalcitrant wastewaters via MECs in the future.