Floating treatment wetlands for the bioremediation of oil spills: A review

Technologies for performance intensification of floating treatment wetland - An explicit and comprehensive review

With the wide application of floating treatment wetland (FTW), the limited performance of FTWs should be improved. A comprehensive review is accordingly necessary to summarize the state-of-the-art on FTWs for performance improvement. An attempt has been made to gain information from literature about technologies to enhance the performance of FTWs. These technologies have been classified into three categories according to their mechanisms: 1) increasing the amount and activity of bacteria; 2) enhancing the growth of plant; and 3) configurable innovations. The design and application of each enhanced FTW have been discussed in detail. Thereafter, all the technologies have been compared and analyzed according to their improvement in pollutant removal and ecological effects. In summary, FTW with additional bio-carriers has a higher potential for future applications with the benefits of wide application conditions, scale-up potential, and the easy combination with other methods to further improve the removal efficiency. The stability and sustainability of these technologies should be further investigated.

Sensitivity index for conservation priority ranking in the oil spill response: A case study for the coastal and marine species and habitat types in the Baltic Sea

Numerous anthropogenic stressors, such as habitat alteration and nutrient enrichment, affect coastal and marine ecosystems around the globe. An additional threat to these ecosystems is accidental oil pollution. The proactive planning of efficient oil spill response actions requires a firm understanding of the spatiotemporal distribution of ecological coastal values at stake, and how these values can be protected in case of an oil spill. In this paper, literature and expert knowledge regarding the life history attributes of coastal and marine species were used to build a sensitivity index to assess the differences in the potential of species and habitat types to be safeguarded from oil. The developed index prioritizes sensitive species and habitat types based on 1) their conservation value, 2) the oil-induced loss and recovery potential, and 3) the effectiveness of oil retention booms and protection sheets to safeguard these entities. The final sensitivity index compares the predicted difference in the state of populations and habitat types five years after an oil spill with and without protective actions. The higher the difference, the more worthwhile the management actions are. Hence, compared to other oil spill sensitivity and vulnerability indexes presented in the literature, the developed index considers the usefulness of protective measures explicitly. We apply the developed index to a case study area in the Northern Baltic Sea to demonstrate the approach. It is noteworthy that the developed index is applicable to other areas as well, as the approach is based on the biological attributes of species and habitat types instead of individual occurrences.

The Effects of Oil and Gas Produced Water on Soil Bacterial Community Structure in the Arid Desert Area

The safe utilization and risk assessment of produced water (PW) from oil and gas fields for desert irrigation have received increasing attention in recent years. In this context, this study aimed to analyze structural changes in soil bacterial community, and assess the environmental impact of PW discharge and irrigation over time. High-throughput sequencing technology was employed to examine the structure of the soil bacterial community in the constructed wetland and its surrounding desert vegetation irrigation region where PW was released for a considerable amount of time (30 years). The results revealed that long-term discharge of PW and irrigation significantly reduced the abundance of the soil bacterial community but did not significantly alter the richness and diversity of the soil bacterial community. Proteobacteria was the dominant bacterial phyla in soil, but in irrigated and drained areas, the dominant bacterial phyla changed from Alphaproteobacteria to Gammaproteobacteria, the Firmicutes abundance was significantly reduced.