In this study, constructed wetland structures were established using different substrates (gravel and aerated concrete), with or without cannas planting. Subsequently , the effects of different working conditions on rainwater runoff pollution were investigated through small experiments. The cost of the constructed wetland with aerated concrete and cannas (4.20 yuan/working condition) was slightly higher (1.00 ~ 2.90 yuan/working condition higher) than those under other working conditions. However, in both cycles of operation (i.e., alternating operation for 30 h and drying for 48 h), the average removal rates of ${\rm{NH}}_4^+ $-N, ${\rm{NO}}_3^- $-N, TN, ${\rm{PO}}_4^{3-} $, TP and CODCr were 73.3%, 47.0%, 85.4%, 56.4%, 76.0%, and 65.5%, respectively. These values were higher than those under other working conditions by an average of 10.9% ~ 18.8%. Thus, this constructed wetland structure had the best effect and the highest cost performance. Therefore, it is suitable for promotion and application.
In this study, a pilot-scale tidal-flow paddy wetland system based on multifunctional coupling was constructed to treat land-based aquaculture tailwater of Macrobrachium rosenbergii. This study explored the purification ability, CH4 emissions, arthropod diversity, and comprehensive benefits of the tidal-flow paddy wetland system to provide a scientific basis for the application of this system. The results showed that the tidal-flow paddy wetland system could effectively purify land-based aquaculture tailwater. The removal capacities of dissolved inorganic nitrogen, total nitrogen, dissolved inorganic phosphorus, and total phosphorus were approximately 54.3%, 44.9%, 42.9%, and 43.0%, respectively. Simultaneously, the system had no negative impact on the external environment and indirectly purifies river water. Compared with conventional paddy fields, the tidal-flow paddy wetland system reduced CO2 and CH4 emissions by 5.4% and 92.5%, respectively. Compared to conventional paddy fields during the flooding period, the abundance of the mcrA gene in the tidal-flow paddy wetland decreased by 82.3%. Moreover, the tidal-flow paddy wetland system improved biodiversity and natural enemy abundance/pest abundance, inhibited pest outbreaks, supported more species, and increased comprehensive benefits compared to the control.
Since the Yingwuzhou Wetland was established over five years ago, we have conducted comprehensive field investigation and monitoring. Constructing a reliable evaluation system with long-term monitoring data is important for the evaluation of coastal ecological restoration projects. Here, we used the emergy analysis method and collected the relevant data through field research, scientific monitoring, and literature review to construct an energy analysis structure chart and emergy value index system for the Yingwuzhou Wetland. The main emergy indexes, such as the natural assets and ecosystem services of the wetland, were analyzed, and its functional performance was compared for different restoration periods. The results show that the total emergy of the natural assets in the Yingwuzhou Wetland in 2021 was 8.92 × 1016 sej, which is equivalent to the emergy-monetary value of 2.247 × 105 yuan; the total emergy of ecosystem services was 8.88 × 1017 sej·a–1. After the implementation of restoration, the ecological quality of Yingwuzhou was significantly improved, and its natural assets and ecosystem service emergy were 5.01 and 5.73 times higher than those before restoration. The emergy self-support ratio (ESR) of the Yingwuzhou Wetland ecosystem was 0.47, and the emergy yield ratio (EYR) and emergy sustainable index (ESI) were 28.29 and 25.03, respectively, indicating that the wetland had high output efficiency and suitable space for sustainable development. This study shows that based on long-term monitoring data, the emergy analysis method can better reflect the effectiveness of coastal ecological restoration projects, and the evaluation system and method can provide reference for similar coastal restoration projects in the future.
中国综合性科技类核心期刊(北大核心)
