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Biotrickling filter (BTF) technology was applied for the treatment of waste gas containing a mixture of chlorobenzene and 1,2-dichlorobenzene. An adapted microbial community was immobilised on a structured packing material. The strategy followed was to reach high removal efficiencies at initially low mass loading rates followed by an increase of the latter. This procedure was successful and resulted in a short start-up period of only 2 weeks. A 3-month operation under steady-state conditions showed good performance, with >95% removal efficiency at a mass loading rate of 1,800 g m-3 day-1. Dimensionless concentration profiles showed that the chlorobenzenes were simultaneously degraded. Low dissolved organic carbon of 15 mg l-1 and stoichiometric chloride concentrations in the trickling liquid indicated complete mineralisation of the pollutant. Transient-state experiments with five times higher mass loading rates caused a decrease in the removal efficiency that recovered rapidly once the mass loading rate returned to its original steady-state level. A progressive increase of the mass loading rate in a long-term performance experiment showed that the removal efficiency could be kept stable between 95 and 99% at loads of up to 5,200 g m-3 day-1 over several days. Above this mass loading rate, the elimination capacity did not increase any further. These results demonstrated that with a well-adapted inoculum and optimal operation parameters, a BTF system with excellent performance and stability that efficiently removes a mixture of cholorobenzene vapours from air can be obtained. [ABSTRACT FROM AUTHOR]

The present work investigates 1-anthraquinone sulphonate (1-AS) biodegradation under (i) aerobic conditions using domestic activated sludge as inoculum, (ii) anaerobic conditions using sludge from an anaerobic domestic wastewater treatment digestor in a sulphate-containing or methanogenic environment, (iii) a combination of anaerobic followed by aerobic conditions. The process was evaluated in terms of primary degradation, i.e. 1-AS elimination and ultimate degradation, as total dissolved organic carbon removal. It was shown that aerobic conditions lead to the complete primary and ultimate degradation, of 1-AS. By contrast, neither under sulphato-reductive nor methanogenic conditions does anaerobic digestion lead to the significant degradation of 1-AS. The use of anaerobic treatment followed by aerobic treatment did not improve degradation. Indeed aerobic post-treatment resulted in the re-appearance of pollutant in the medium even though this had been partly degraded under anaerobic conditions. [ABSTRACT FROM AUTHOR]

Sterile inflammation after injury is important for tissue restoration. In injured human and mouse tissues, macrophages were recently found to accumulate perivascularly. This study investigates if macrophages adopt a mural cell phenotype important for restoration after ischemic injury. Single-cell RNA sequencing of fate-mapped macrophages from ischemic mouse muscles demonstrates a macrophage-toward-mural cell switch of a subpopulation of macrophages with downregulated myeloid cell genes and upregulated mural cell genes, including PDGFRβ. This observation was further strengthened when including unspliced transcripts in the analysis. The macrophage switch was proven functionally relevant, as induction of macrophage-specific PDGFRβ deficiency prevented their perivascular macrophage phenotype, impaired vessel maturation and increased vessel leakiness, which ultimately reduced limb function. In conclusion, macrophages in adult ischemic tissue were demonstrated to undergo a cellular program to morphologically, transcriptomically and functionally resemble mural cells while weakening their macrophage identity. The macrophage-to-mural cell-like phenotypic switch is crucial for restoring tissue function and warrants further exploration as a potential target for immunotherapies to enhance healing., (© 2024. The Author(s).)