Abstract In view of the uneven distribution of water resources in the multi-lock and dam plains, the insufficient connection and layout of river systems such as isolated wetlands and pond barriers in floodplains, resulting in insufficient water resources allocation capacity, poor flood storage and drainage, and serious water ecological damage. Taking Langfang City as an example, based on graph theory and complex network theory, considering the flow capacity of DAMS and gates and human demand for water landscape, the importance of rivers and canals in river network—optimizing river network layout—establishing comprehensive evaluation index system of river network layout—comprehensive evaluation is taken as the main line to evaluate and determine the importance of rivers and canals in river network. The overall layout of river network connectivity in the north, middle and south regions of Langfang is optimized and evaluated. The results show that there are large differences in the current layout of waterways in the three regions, with poor river network connectivity in the southern part of the Langfang. The overall layout of the optimized river network was improved by 13.0%, 3.0% and 12.4% compared to the overall layout in Langfang. The optimized scheme provides technical support and theoretical basis for the optimal implementation of the regional river and lake connectivity project in Langfang.
The nature-based solutions (NBS) concept is closely related to sustainability, harmonious and green development, resource rational exploitation, coupled human health and environment, and ecological protection priority.Bio-slow sand filtration (BSSF) technology is a green water treatment technology with low energy consumption, simple operation, and a high removal rate of contaminants.To achieve low cost, easy management and secondary pollution avoidance in the process of removing contaminants in drinking water, the rational selection of biofiltration materials and the optimal combination of particle size are particularly important based on NBS.To effectively remove turbidity, organic pollutants, bacteria, and ammonia nitrogen by BSSF, three scenarios were summarized by considering the influence of sensitive parameter optimization and the external environment (temperature and velocity).We designed three BSSF water treatment testing devices, which were filled with bio-filter materials with different particle sizes (0.15-0.3 mm, 0.3-0.9mm, 0.9-1.35mm, and 0.3-0.9mm), to carry out an indoor testing comparison analysis.We optimized important parameters of BSSF water treatment technology (such as the bio-filter material particle size and filling heights, filtering velocity, and suitable temperature) to obtain the best design and operational parameters of BSSF water treatment technology.The optimum operating conditions were: filter material particle size of 0.3-0.6 mm, filling height of 0.6-0.9m, filtering velocity of 0.2-0.6 m/h, and a suitable temperature of 15-35ºC.To ensure the water quality of the filtered water, we optimized the design parameters of traditional BSSF technology, which could save land and reduce beginning time.BSSF water treatment technology based on NBS is useful for promoting the engineering application of drinking water treatment and regional water security.
Use pyrometallurgical to reclaim scrapped lead-acid battery has the defact of high energy consumption and severe pollution.The reclaim rate is only over 80%.At present,useing pyrometallurgical-hydrometallurgical to reclaim scrapped lead-acid battery has improved the reclaim rate above 10% and decrease pollution.In this paper introduce the technology of producing lead-stibium alloy and Lead Sulfate Tribasic,chrome yellow series of products.
On the west bank of the intake bay of a nuclear power plant at Nanwan, southern Taiwan, a recent outbreak of sea anemones has eliminated most branching corals at the site. In this habitat currently dominated by sea anemones, the abundance of Dick's damsel, Plectroglyphidodon dickii Lienard 1983, has increased more markedly than the sympatric congener, P johnstonianus Fowler and Ball 1924. To study whether the distribution patterns of the 2 Plectroglyphidodon damselfishes were underlain by food availability and feeding habit plasticity, the reef area in the embayment was divided into 2 different zones, zone A dominated by Acropora corals and zone B dominated by a sea-anemone, and both stomach content and stable isotope analyses were used to delineate feeding habits of these 2 damselfishes in these 2 zones. Stomach contents showed that the major food items for P. dickii in zone A were filamentous algae (33.4%) and coral polyps (22.3%), while in zone B, they were filamentous algae (35.8%) and sea anemones (28.2%). In contrast, coral polyps were the major food item for P johnstonianus in both zones (accounting for 75.5% in zone A and 67.5% in zone B). Analyses of δ 13 C and δ 15 N values concurred that coral polyps were the major nutrient source of P johnstonianus. In addition, the contributions of both coral polyps and sea anemones to P. dickii were verified. Overall, it was postulated that in the sea anemone-dominated habitat, sea anemones were substituted for coral polyps in the diet of P. dickii, but similar plasticity did not occur in P. johnstonianus. Thus the higher feeding plasticity of P dickii might have made it possible to more-successfully immigrate to the newly developed habitat.
To understand the water quality status of the main stream of the Nyang River and the main pollution factors affecting the water body, surface water samples from 10 monitoring sections along the mainstream of the Nyang River were collected during the high-water (July-September) and low-water (January-March) seasons in 2018.Water quality indexes of chemical oxygen demand (COD), ammonia nitrogen (Nh 3 -N), total nitrogen (TN), total phosphorus (TP), Pb and Cd were selected for analysis.Water quality of the mainstream was then evaluated by single-factor assessment, comprehensive pollution index evaluate and principal component analysis.The results of single-factor evaluations show that COD is the main factor determining the type of water quality in the Nyang River, which belongs to Class III when COD is not included in the evaluation.The results of the comprehensive pollution index method show that the water quality of the Nyang River is relatively good as a whole.To clean the water body, more than 70% of the monitoring sections need to meet the Class II water quality standard.COD and TN are the main pollution factors of the main water body of the Nyang River.The results of principal component analysis (PCA) show that the water quality of the Nyang River is mainly affected by Nh 3 -N, Pb, Cd, TP and COD, and that the area with the most severe pollution is the middle reaches of the river.The three methods are an organic combination of qualitative and quantitative evaluations, and the evaluation results were largely consistent between methods.Generally, the water quality in the high-water season of the Nyang River is better than that in the low-water season.however, there are many differences between the screening results of water pollution factors; therefore, a variety of important methods are used to analyse the main pollution factors of the water body.
To quantitatively study the hydrodynamic changes in different river morphologies and clarify the impact of morphological changes on river ecosystems, this study examined a section of the Nansha River near Laoniuwan in the Haidian District, Beijing, and characterized different river morphologies by river sinuosity. The River 2D model was used for simulation and analysis, and the depth and velocity diversity indices were introduced to quantify the distribution of depth and velocity under different sinuosities. Cyprinus carpio was selected as the target fish in this study, and its suitability curve was determined using literature and field surveys. Combined with the simulation results, a weighted usable area curve was established to identify its inflection point and maximum value and determine the ecological flow in the river under different sinuosities, that is, to clarify the relationship between sinuosity and ecological flow. The results showed that the lower the sinuosity, the worse the depth and velocity diversity, but a greater sinuosity did not lead to better depth and velocity diversity. The depth and velocity diversity of a sinuosity of 1.5 were better than those of 1.89 in general, except for low flow conditions (Q = 5 m3/s). For rivers with water use restricted by nature and society and where ecological needs exist, ecological engineering that appropriately changes the planform of rivers can be considered to increase the diversity of river/channel geometry and provide a basis for the ecological restoration of rivers.
The value of agro-ecosystem services is closely related to crop yield.As a production input component in an agro-ecosystem, agro-ecosystem services have practical value.It is generally believed that agroecosystem services are substitutes for purchase investment and can decrease agricultural production costs.Crop yield increases may negatively affect agro-ecosystem protection, and conversely, agroecosystem protection may result in crop yield reductions.Based on the established production model of agro-ecosystems, we determined the reasonable substitutive conditions and production outputs, and we quantitatively studied the ratio of the land area for agricultural production to that for ecosystem services.With the upper Yongding River Basin in China as the study area, we calculated agricultural yield elasticity and concluded that the corresponding crop yield would be reduced by 2.7% when the land area for ecosystem services in the basin increased by 1.0%.At present, the ecological service value of the Yongding River Basin showed an increasing trend.
Due to the shortage of water resources in China, the state has implemented a series of rainwater harvesting projects.The safety of water quality cannot be guaranteed due to the lack of an effective construction, running, and management system.Slow filters are low-maintenance systems that do not require special equipment.In order to improve the performance of SSF in terms of the removal of bacteria and solid granules, e.g., the microorganisms attached to the surface of a single grain of the filtering material under a scanning electron microscope (50×) have been studied.Based on the improvements of conventional slow sand filtration (SSF), the bio-slow sand filtration method has effectively mitigated and helps to remove bacteria and other microbiological contaminants, as well as heavy metals, ammonia, nitrogen, organic material, and turbidity of the harvested rainwater.The removal efficiency of bioslow sand filtration was approximately 20-30% on particulate organic carbon, above 95% on ammonianitrogen, and better than 96%, 95%, 95%, 80%, 70%, and 60% on Cu 2+ , Cd 2+ , Fe 2+ , Zn 2+ , Mn 2+ , and Pb 2+ , respectively.The effluent quality meets the requirements of "standards for drinking water quality" in China.The result indicated the bio-slow sand filtration method could achieve better water quality results as an available water treatment technology.
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