Genetic Algorithm-Based Fuzzy Comprehensive Evaluation of Water Quality in Dongzhaigang

Water pollution characteristics and analysis of Chaohu Lake basin by using different assessment methods

In the context of the water environmental protection and local economic sustainable growth, it is of great importance to conduct a comprehensive water quality assessment in Chaohu Lake basin. In this study, dissolved oxygen (DO), permanganate index (COD_Mn), 5-day biochemical oxygen demand (BOD₅), ammonia nitrogen (NH₃-N), total nitrogen (TN), and total phosphorus (TP) were investigated monthly at 24 sampling sites in Chaohu Lake basin during 2015 to 2017. Five methods were used to evaluate water quality and identify dominant pollutants. Results showed that the dominant pollutants in Chaohu Lake were TN (4.17~11.61 mg L^-1) and TP (0.27~0.75 mg L^-1). The upstream of Chaohu Lake was influenced by Nanfei River, Shiwuli River, and Paihe River, and water quality of the upstream (eutrophic) was worse than that of the downstream (mesotrophic) part of Chaohu Lake. Comprehensive Water Quality Identification Index Method (CWQII) can better assess the water quality compared with the other methods by providing qualitative and quantitative analysis. The index values assessed by CWQII method for Nanfei River, Shiwuli River, and Paihe River were 5.819, 5.986, and 5.141, respectively, and water quality were all assessed as grade V. Overall, water quality of Chaohu Lake has been slightly improved during 2015~2017, but water quality of western inflowing rivers was still heavily polluted. These findings provide valuable information and guidance for water pollution control and water resource management in Chaohu Lake basin. Several feasible measures are proposed.

An integrative model to assess water quality in China's Lake Taihu: Comparing single-factor and multifactor assessments

To determine the differences between single-factor assessment (SFA) and multifactor assessment (MFA) of the water quality in Lake Taihu Basin in China, a software program was developed to perform absolute distance (AD) computations between SFAs and MFAs that refer to the Nemerow comprehensive index (NCI) and fuzzy comprehensive assessment (FCA). Symbolic models were established to describe the computation types and sequences that are involved in the models above. Water data that were obtained weekly from 7 monitoring sites (MSs) in the basin over 10 years were tested to generate water quality grades and ADs. Our results corroborated that the MFAs would approximate the SFA when each water quality indicator (WQI) is in its worst or best state. In addition to supporting that SFA ≥ NCI ≥ FCA, the ADs illustrated that FCA was inappropriate for process integration unless all WQIs had the same grading standards. The annual water quality grades of most MSs of Lake Taihu Basin and time could be fitted to quintic polynomials with relative average deviations (RADs) of below 5%. Integr Environ Assess Manag 2019;15:135-141. © 2018 SETAC.

Dynamic Comprehensive Benefit Evaluation of the Transnational Power Grid Interconnection Project Based on Combination Weighting and TOPSIS Grey Projection Method

With the rapid development of the global economy, the interconnection of power grids has become an objective law and a trend of the power industry development. The implementation of power grid interconnection projects, especially transnational power grid interconnection projects, will bring us substantial benefits. To demonstrate these benefits comprehensively, we designed a comprehensive evaluation index system with multiple international engineering characteristics. The index system takes the influencing factors of economic, social, environmental and technical benefits into account. In order to improve the rigidity and power of weight determination, we proposed the least squares method which combines the order relation method and the factor analysis method. Furthermore, the limitation of the one-way evaluation was effectively overcome by combining TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution), grey relation analysis method and vector projection method. In addition, we adjusted the potential impact of the time on evaluation by using the quadratic weighted algorithm, so that we can dynamically evaluate the comprehensive benefits. Finally, we verified the established index system and evaluation model through an example of eight different investment plans of a transnational high voltage direct current (HVDC) transmission project. Altogether, results from this paper will provide a guidance reference and decision support for the grid corporation to invest in transnational power grid interconnection projects.

Detection of contaminants in water supply: A review on state-of-the-art monitoring technologies and their applications

Water monitoring technologies are widely used for contaminants detection in wide variety of water ecology applications such as water treatment plant and water distribution system. A tremendous amount of research has been conducted over the past decades to develop robust and efficient techniques of contaminants detection with minimum operating cost and energy. Recent developments in spectroscopic techniques and biosensor approach have improved the detection sensitivities, quantitatively and qualitatively. The availability of in-situ measurements and multiple detection analyses has expanded the water monitoring applications in various advanced techniques including successful establishment in hand-held sensing devices which improves portability in real-time basis for the detection of contaminant, such as microorganisms, pesticides, heavy metal ions, inorganic and organic components. This paper intends to review the developments in water quality monitoring technologies for the detection of biological and chemical contaminants in accordance with instrumental limitations. Particularly, this review focuses on the most recently developed techniques for water contaminant detection applications. Several recommendations and prospective views on the developments in water quality assessments will also be included.

Risk assessment of trace metal-polluted coastal sediments on Hainan Island: A full-scale set of 474 geographical locations covering the entire island

Hainan Island is the second largest island and one of the most famous tourist destinations in China, but sediment contamination by trace metals in coastal areas is a major issue. However, full-scale risk assessments of trace metal-polluted coastal sediments are lacking. In this study, coastal surface sediments from 474 geographical locations covering almost the entire island were collected to identify risk-related variables. Controlling factors and possible sources of trace metals were identified, and the toxicity effects were carefully evaluated. Our results suggest that trace-metal pollution in coastal sediments, which was mainly caused by Pb, Zn and Cu emissions, has primarily resulted from industrial sewage and shipping activities and has threatened the offshore ecosystem of Hainan Island and warrants extensive consideration. This is the first study that has systematically investigated trace metal-polluted coastal sediments throughout the entirety of Hainan Island and provides solid evidence for sustainable marine management in the region.