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Odor emission is one of the most common problems associated with dead animals composting. Biofiltration treatment for eliminating exhaust odors formed during dead pigs and manure composting has been studied. The composting and biofiltration process consisted of two series of tests. Composting experimental trials lasted 6 weeks, and composting was performed using six pilot-scale reactor vessels. A total of 37 kinds of volatile organic compounds (VOCs) present in the air were identified, and temporal variations were determined during the 42 days of composting. Dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and trimethylamine (TMA) were identified as the main odors VOCs component according to odor active values (OAVs). Nine biofilter vessels containing mature compost were used in studying the effect of different (30, 60, and 100 s) empty bed retention times (EBRT) on the simultaneous removal efficiencies (REs) of NH3, DMS, DMDS, DMTS, and TMA. Results indicated that the inlet concentration of NH3 applied was 12–447 mg m−3, and the average removal efficiencies were 85.4%, 88.7%, and 89.0% for EBRTs of 30, 60, and 100 s, respectively. The average REs of DMS, DMDS, DMTS, and TMA were 79.2%–95.4%, 81.9%–94.0%, 76.7%–99.1%, and 92.9%–100%, respectively, and their maximum elimination capacity (ECs) were 220, 1301, 296, and 603 mg m−3 h−1, respectively. The optimal EBRT for the stimulation removal of NH3, DMS, DMDS, DMTS, and TMA was 60 s. Implications: Dimethyl sulfide (DMS), dimethyl disulfide (DMDS), dimethyl trisulfide (DMTS), and trimethylamine (TMA) were identified as the main odors VOCs component during dead pigs and manure composting. Biofilter with mature as media can be used to stimulation remove NH3, DMS, DMDS, DMTS, and TMA, the optimal empty bed retention times EBRT was 60 s. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lactic acid is the major composition of the fermentation broth for PHA production. • Effective MMC was enriched by using pig farm sludge and SRTs of 8 days. • PHA yield and content of 0.57 gPHA-COD/gCOD and 50% were in accumulation reactor. • The different MMCs tended to be similar and the dominant bacteria was Paracoccus. Lactic acid fermentation broth derived from pig manure and apple waste is a potential high-quality feedstock for production of the biodegradable plastic polyhydroxyalkanoate (PHA). Enrichment of active PHA-synthesizing bacterial consortia, namely mixed microbial culture (MMC), is an important factor in high-efficiency synthesis of PHA. In this study, two types of aerobic sludge (pig farm sludge and municipal sludge) were selected to acquire active MMCs in the enrichment process with sludge retention times of 2 and 8 days using the lactic acid fermentation broth. Batch reactors and PHA accumulation reactors were used to evaluate the MMC activity. Results showed that pig farm sludge was acclimated to the superior MMC with the maximum PHA content of 25% during the enrichment process with sludge retention time of 8 days. The structure of microbial communities in all treatments tended to be similar after 45 days' enrichment, and the dominant bacteria were genus Paracoccus with abundance of 15.41–41.45%. The maximum dry cell weight, PHA content, and PHA yield of batch reactors using the superior MMC were 0.69 g/L, 36%, and 0.86 g PHA-COD/g COD, respectively. Dry cell weight concentrations reached 3.16 g/L in the PHA accumulation reactor with PHA content of 40–50% and PHA yield of 0.57 g PHA-COD/ g COD. The findings of this study provide an effective enrichment strategy for MMCs, which could improve the high efficiency synthesis of PHA from the fermentation broth of agricultural wastes and enhance the economy of PHA production at a marketable scale. [ABSTRACT FROM AUTHOR]