Chunxue Zhang

Eutrophication in rural ponds has become a widespread environmental concern, particularly in regions affected by agricultural irrigation. This study proposes an innovative Submerged Macrophytes–Daphnia magna combined remediation technology, aiming to synergistically improve water quality in naturally eutrophic ponds. Experimental water was sourced from rural ponds with preserved natural phytoplankton and bacterial communities. Treatments included low- and high-density D. magna, two submerged macrophyte species (Myriophyllum aquaticum and Ceratophyllum demersum), and their combinations. Results showed that combined treatments had no significant effect on pH but improved water transparency by up to 63.6% and significantly increased dissolved oxygen. Nutrient removal was notably enhanced in combined groups, with low-density D. magna + M. aquaticum achieving TN, TP, and NO₃⁻-N reductions of 56.1%, 63.2%, and 58.7%, respectively. Both macrophytes effectively mitigated NH₄⁺-N accumulation caused by D. magna, with M. aquaticum showing stronger inhibition. Furthermore, low-density D. magna reduced phytoplankton density, cyanobacteria density, chlorophyll-a, and microcystins by 74.8%, 80.3%, 68.9%, and 71.2%, respectively. This combined bioremediation approach demonstrates high ecological efficiency, scalability potential, and practical applicability for rural pond restoration.

A field trial was conducted in Tianjin to assess the impact of “three-compartment septic tank (SPT) + soil wastewater infiltration system (SWIS)” on vegetable crop soil, determine the SPT effluent quality, and establish the consumer safety of vegetables grown above the SWIS. The effluent total nitrogen (TN), total phosphorus (TP), ammonium-N (NH₄⁺-N), chemical oxygen demand (COD), and 5-d biochemical oxygen demand (BOD₅) levels all varied largely every month. The average COD failed to meet the criteria of the Standard for Irrigation Water Quality (No. GB5084-2021) but significantly influenced bacterial community distribution. Hierarchical clustering disclosed seasonal variation in SPT effluent. SWIS treatment of rural black-grey water significantly affected both the vegetable soil TN and TP content, and it promoted microbial community diversity and richness in deep soil. The treatment also increased the relative abundances of the beneficial bacterial genera Thiobacillus and Arthrobacter by more than 320% and decreased the relative abundance of the pathogenic bacterial genus Streptomyces in vegetable soil by more than 20.33%. The faecal coliform levels and ascaris egg mortality rates in the vegetable crop soils lay within published human health and safety thresholds both before and after SWIS treatment. All vegetable crops grown above the SWIS were fit for human consumption. The VC level in the vegetables planted in experimental households were higher than those for the vegetables planted in ordinary households. The present work provides reasonable theoretical and empirical bases for optimising the “SPT + SWIS” process and SPT discharge standards in rural areas.

The improvement of rural living standards in developing countries and the continuous upgrading of the rural industrial economy have prompted the diversification of rural areas and residential forms. Thus, an integrated rural sewage treatment process has gradually become the mainstream technology for rural sewage treatment. Numerous studies have reported the effects of ecological wastewater treatment. Meanwhile, the relevant process technologies, evaluations, and operating models of the integrated rural sewage treatment process have yet to be thoroughly summarized. This review aims to fill these gaps. First, the applicability of artificial wetland, soil infiltration, stabilization pond, and integrated rural sewage treatment process technology in rural sewage treatment are outlined and compared. Second, the process flow, technical characteristics, and economic indicators of typical integrated sewage treatment processes (i.e., Anoxic/Oxic (A/O) process, Membrane Bio-Reactor (MBR) process, biological contact oxidation process, Sequencing Batch Reactor Activated Sludge (SBR) process) are introduced. The engineering application effects of the integrated rural sewage treatment process in different countries are also described. Third, the practical and effective evaluation methods of the integrated rural sewage treatment process are introduced. Bearing in mind the current operation and maintenance management modes of the integrated rural sewage treatment process in developed and developing countries, combined with the national conditions of developing countries, the prospect section provides development proposals for further optimization and improvement of the integrated rural sewage treatment process in developing countries.

Mercury (Hg) exposure poses serious health risks to humans, resulting in extensive investigations examining Hg accumulation, biotransformation and uptake in crops. In this investigation, Hg accumulation in potato tubers due to bioaccumulation processes was determined and bioconcentration factors affecting bioaccumulation were identified using a greenhouse experiment. Our results showed that the percentage of available Hg concentrations from total Hg in soil samples were less than 1.2%, indicating that soils used in our experiment exhibited a high binding strength for Hg, with alkaline soil recording the lowest available Hg/total Hg ratio. Results indicated that soil type and Hg treatment, as well as their interactions, significantly affected Hg accumulation in potato tubers (P < 0.01). Importantly, our results also indicated that potatoes grown in soil with a Hg concentration two times higher than the Chinese Environmental Quality Standard exhibited no obvious toxic effects on humans; Bioconcentration factors (BCF) values (<0.04) suggested that potatoes can be considered as a low Hg accumulating species and suitable for human consumption. Potato yields in acidic soil were lower than those in neutral or alkaline soils, making this medium unsuitable for growth.

Transition of a lamellar structure to a cubic phase and its effect on the thermodynamic properties of 4D ₁₆ organogels.

The development of monitoring technologies in smart grid is undergoing an essential transition from periodical magnitude‐based measurement by supervisory control and data acquisition (SCADA) to real‐time phasor measurement unit (PMU)‐based wide area monitoring and control. The implementation of PMUs can substantially facilitate grid‐wide state estimation and operation control, which is dependent on an effective PMU placement strategy. In this study, the optimal PMU placement (OPP) problem is investigated with respect to zonal voltage controllability and voltage magnitude estimation in cooperation with SCADA. In particular, the OPP is formulated as a multi‐objective minimal Ncut partitioning problem, in which various operating scenarios are represented by probabilistic load flows to achieve a general solution for planning purpose. Spectral clustering is employed to efficiently find the optimal clustering boundaries, which indicate the resulting placement layout. The proposed placement scheme is tested on New England 39‐bus and IEEE 118‐bus systems. Simulation results demonstrate the effectiveness of the proposed approach.

Herein, a bent-core dihydrazide derivative (BP8-C) showed unusual solvent-induced optional self-assembly behaviour, e.g. crystalline gels obtained from ethanol (EtOH) and liquid crystalline gels obtained from chloroform (CHL) and toluene (Tol). Packing models in crystalline and liquid crystalline states are confirmed by the XRD method. It was demonstrated by fluorescence spectroscopy that gelators aggregate in EtOH in a way n = 2.13 (Avrami parameter). Interestingly, liquid crystalline gels obtained in CHL display better elastic property with 200% cross-over strain and act as Newtonian fluid at low shearing rate regions, whereas the crystalline gels show better viscidity with low cross-over strain (3%). Moreover, BP8-C xerogels obtained from CHL exhibit T_g transition followed by cold crystallization upon the first heating run, whereas an unknown mesophase, Col_h phase, and a broadened and super-cooled crystallization were observed during cooling. In contrast, xerogels obtained from EtOH show enantiotropic Col_h mesophase, and sharp crystallization transition. The different gelation behaviour and the liquid crystalline properties of the xerogels obtained from CHL and ethanol were attributed to different molecular aggregates due to interaction between ethanol and the gelators, as confirmed by ¹H NMR and FTIR spectroscopy. We emphasize the role of solvent on the self-assembly degree of gelators, which can further influence the properties of gels and the corresponding xerogels.

Herein, we report the gelation behaviour and gel properties of two-component organogels consisting of 1,4-bis[(3,4-bisoctyloxyphenyl) hydrozide] phenylene (BPH-8) and a photoresponsive gelator 4-[3,5-(bisoctyloxyphenyl)]-9-anthracene formyl hydrazine (MB8). It was demonstrated that the mixture of BPH-8 and MB8 showed self-sorted aggregation behaviour in ethanol. A gradient cooling procedure was used to obtain self-sorted gels of BPH-8 and MB8. Kinetics of gelation of the two component gels showed that D_f values of MB8 fibers decreased due to the presence of BPH-8 gel. The two-component gels showed visible light (λ_{visible light} = 350–570 nm) induced gel–gel transitions due to the orthogonal self-assembly of two gelators through the trans–cis conformation transition of –CN– bond of MB8 component. In addition, the stable patterned two-component gel was achieved using a special shape mask, which enabled the gels to be irradiated by visible light in a particular area. The irradiated gels showed weak emission, reduced storage modulus, a shorter linear viscoelastic region, and higher wetting angle compared to that unirradiated region due to the collapse of the MB8 aggregates under visible light.