Microalgae-assisted heterotrophic nitrification-aerobic denitrification process for cost-effective nitrogen and phosphorus removal from high-salinity wastewater: Performance, mechanism, and bacterial community.

A microalgae-assisted heterotrophic nitrification-aerobic denitrification (HNAD) system for efficient nutrient removal from high-salinity wastewater was constructed for the first time as a cost-effective process in the present study. Excellent nutrient removal (∼100.0 %) was achieved through the symbiotic system. The biological removal process, biologically induced phosphate precipitation (BIPP), microalgae uptake, and ammonia stripping worked together for nutrient removal. Furthermore, the biological removal process achieved by biofilm contributed to approximately 55.3-71.8 % of nitrogen removal. BIPP undertook approximately 45.6-51.8 % of phosphorus removal. Batch activity tests confirmed that HNAD fulfilled an extremely critical role in nitrogen removal. Microalgal metabolism drove BIPP to achieve efficient phosphorus removal. Moreover, as the main HNAD bacteria, OLB13 and Thauera were enriched. The preliminary energy flow analysis demonstrated that the symbiotic system could achieve energy neutrality, theoretically. The findings provide novel insights into strategies of low-carbon and efficient nutrient removal from high-salinity wastewater.

The effects of nutrient loading from different sources on eutrophication in a large shallow lake in Southeast China.

Lake water eutrophication has become one of the leading obstacles to sustainable economic development in China. Research on the effects of mainstream currents on reservoirs has been relatively underdeveloped compared with research on tributaries, though changes in the water-sediment transport regime in a downstream river may affect nutrient transport behavior in a lake connected to that river. This is particularly problematic because certain wastewater sources, including runoff from agricultural wastes and industrial discharges, adversely affect lake water. Our study focused on Sanshiliujiao Lake, a significant drinking water source in Fujian, Southeast China, that has suffered considerably from eutrophication over the past few decades. This study aimed to estimate the phosphorus and nitrogen loads to the lake, exploring their sources and their ecologic effects using in situ observation and the export coefficient model. Our results showed that the pollution loads of total phosphorus (TP) and total nitrogen (TN) were 2.390 and 46.040 t/year, respectively, most of which were derived from the water diversion (TP 45.7%, TN 29.2%) and non-point source (TP 30.2%, TN 41.6%). The TN input was the highest in East river (3.557 kg/d), followed by Red river (2.524 kg/d). During the wet season, the input of TP and TN increased by 14.6 and 18.7 times, respectively, but produced only slight variations in concentration. Water diversion enriched the nutrients inputs and altered the structure and abundance of phytoplankton communities. In addition, when water flows from the main river directly to Sanshiliujiao Lake, algal blooms in river-connected lakes are significantly exacerbated, so our study may also serve as a theoretical basis to regulate eutrophication in Sanshiliujiao Lake.

Natural Polymer Template for Low-Cost Producing High-Performance Ti3C2Tx MXene Electrodes for Flexible Supercapacitors.

MXenes, two-dimensional (2D) transition-metal carbides and nitrides with high electrical conductivity, show outstanding potential for energy storage applications. However, the aggregation and restacking of 2D MXene nanosheets seriously decrease the performance of MXene-based electrodes. Instead of using high-cost artificial templates, herein, we select natural rubber (NR) latex-containing uniform sub-macroparticles as sacrificial templates and successfully construct three-dimensional interconnected porous MXene foam. This porous structure effectively prevents the restacking of MXene nanosheets and accelerates the transfer of electrolyte ions during charging and discharging, which significantly enhances capacitance and rate performance. By adjusting the loading of latex, we find that MXene foam (MXF)-70% provides both improved specific capacitance of 480 F g-1 at 2 mV s-1 and superior rate performance (42.1% residual at 1 V s-1) with excellent cycling stability of 97.1% capacitance retention after 10000 cycles at 50 mV s-1. Additionally, the low cost of natural rubber latex provides an alternate route to produce foam electrodes on a large scale for portable and integrated supercapacitors.

Ecosystem service benefits and costs of deep-sea ecosystem restoration.

Deep-sea ecosystems are facing degradation which could have severe consequences for biodiversity and the livelihoods of coastal populations. Ecosystem restoration as a natural based solution has been regarded as a useful means to recover ecosystems. The study provides a social cost-benefit analysis for a proposed project to restore the Dohrn Canyon cold water corals and the deep-sea ecosystem in the Bay of Naples, Italy. By incorporating ecosystem service benefits and uncertainties related to a complex natural-technological-social system surrounding restoration activities, the study demonstrated how to evaluate large-scale ecosystem restoration activities. The results indicate that an ecosystem restoration project can be economic (in terms of welfare improvement) even if the restoration costs are high. Our study shows the uncertainty associated with restoration success rate significantly affects the probability distribution of the expected net present values. Identifying and controlling the underlying factors to improve the restoration successful rate is thus crucial.

Frail elders' views of Tai Chi.

The beneficial effects of Tai Chi on an elder's well-being have been well documented; however, not many frail elders practice it. The purpose of this descriptive study was to explore the perspectives frail elders have about Tai Chi, including its movements, practice frequency and duration, and practice preferences. Using focus groups, 40 frail elders who lived in long-term care facilities were interviewed. Results indicated that Tai Chi styles with slow and large motions were manageable. Subjects preferred to practice Tai Chi in a group of 10 to 20 people, twice a week with 31 to 60 minutes of practice in the early morning or in the afternoon after napping. The practice locations should be wide, flat, non-disturbed, and well-ventilated. Tai Chi instructors should be experienced, gentle, considerate, and have clarity in expression. Findings can be used to design a simple Tai Chi program that is specifically tailored to the needs of frail elders.