Performance and microbial community analysis of a bio-contact oxidation reactor during the treatment of low-COD and high-salinity oilfield produced water

The multistage bio-contact oxidation reactor (BCOR) is a widely used biological strategy to treat wastewater, however, little is known about the performance and microbial community information of BCOR during the treatment of low-COD and high-salinity oilfield produced water. In this study, the performance of a multistage BCOR in treating produced water was investigated. The result suggested the BCOR could efficiently remove COD, BOD₅, NH₄⁺-N, and oil pollutants. Besides, high-throughput sequencing analysis revealed that oil content was the main variable in shaping the community structure. The highest total relative abundance of potential pollutants degraders in first BCOR stage suggested significant role of this stage in pollutants removal. In addition, the correlation analysis disclosed the key functional genera during the degradation process, including Rhodobacter, Citreibacter, and Roseovarius. Moreover, network analysis revealed that the microbial taxa within same module had strong ecological linkages and specific functions.

Fungal proliferation and hydrocarbon removal during biostimulation of oily sludge with high total petroleum hydrocarbon

A laboratory-scale study was conducted to investigate the effect of bioaugmentation (BA) and biostimulation (BS) on the remediation of oily sludge with high total petroleum hydrocarbon (TPH) content (269,000 mg/kg d.w. sludge). TPH concentration significantly decreased by 30.4% (P < 0.05) in the BS treatment after 13-week incubation, and 17.0 and 9.1% of TPH was removed in the BA and control treatments (amended with sterile water only), respectively. Aliphatic and other fractions (i.e., saturated n-alkanes and cyclic saturated alkanes) were reduced in the BS treatment, whereas no decrease in aromatic hydrocarbons occurred in any treatment. Gas chromatography-mass spectrometry analysis of aliphatic fractions showed that low-chain-length alkanes (C8-C20) were the most biodegradable fractions. The BS treatment supported fungal proliferation, with Sordariomycetes and Eurotiomycetes as the dominant classes. BS increased fungal diversity and decreased fungal abundance, and changed bacterial community structure. The findings show the potential of using BS to treat oily sludge with high TPH content. Graphical abstract.

The HIV/AIDS epidemic among young people in China between 2005 and 2012: results of a spatial temporal analysis

OBJECTIVES

Despite a recent increase in the HIV/AIDS epidemic among young people in China, youth-specific HIV data are limited.

METHODS

In total, 56 621 individuals with HIV/AIDS, aged 15-24 years, registered in the Case Reporting System of China between 2005 and 2012 and having complete spatial information were included in the present analysis. Spatial autocorrelation (general and local) and space-time scanning were performed using the ArcGIS 10.2 and SaTScan 9.3 software, respectively.

RESULTS

During 2005-2012, the number of reported HIV/AIDS cases and the proportion of HIV cases increased while the proportion of AIDS cases decreased. Sexual contact became the predominant route of transmission in later years. Spatial analysis showed marked geographical variations in HIV infection among young people throughout China during 2005-2012. The number of new hotspots increased over time. They were mainly localized to southeastern coastal areas, southwestern frontier provinces or autonomous regions (of Guangxi, Yunnan and Sichuan) and Beijing municipality. Later these hotspots disappeared and new hotspots were found in the northeast of the country. Significant clusters of HIV-positive cases were identified in three different time periods, which indicated high HIV transmission among young Chinese people in the recent past. The risk of HIV infection was highest in the first cluster (2009-2012; this cluster was the largest in size) covering the provinces of Guizhou and Yunnan, the Chongqing municipality, Guangxi, and the province of Sichuan. The second cluster (2010-2012) was mostly located in Shanghai, South Jiangsu, Zhejiang and South Anhui, while the third cluster (2010-2012) was located in Beijing and Tianjin.

CONCLUSIONS

Target-specific comprehensive behavioural interventions are urgently needed to contain the HIV epidemic among young people.

Identification of silver nanoparticles in Pimephales promelas gastrointestinal tract and gill tissues using flow field flow fractionation ICP-MS

To further understand potential nanoparticle toxicity, silver nanoparticles were identified in both the GI tract and gill of fathead minnows using field-flow-fractionation ICP-MS.

Factors contributing to reinfection with schistosomiasis japonica after treatment in the lake region of China

The prevalence of schistosomiasis due to S. japonicum is focally high in the lake regions of China, and reinfection after treatment with praziquantel is frequent. In this study, the total reinfection rate among 740 treated persons was 12.9%. Factors associated with reinfection were age and sex, water contact and the distance from homes to snail habitats. The reinfection rate was higher among men (15.0%) than among women (8.3%). The frequency of water contact is the main factor in reinfection. Among persons with more than 120 and 10-120 water-contact days, the reinfection rates were 24.0% and 16.4%, respectively. The reinfection rates among people living 0 m, 500 m and 1000 m from snail-ridden areas were 14.1%, 8.3% and 4.3%, respectively. Fishing was the most frequent reason for water-contact, followed by herding animals and playing in water; reinfection rates among those engaging in these activities were 36.4%, 16.3% and 22.9%, respectively. Reinfection is clearly a problem, and since much of it is connected with essential economic activities, the cycle of infection and reinfection is not likely to be broken until effective methods for eliminating reservoirs of infection are developed.