With global warming, urbanization, and the intensification of human activities, great pressures on river ecosystems have caused ecosystem degradation, the decline in habitats and biodiversity, and the loss of function. Ecological restoration technologies (ERTs) in rivers are effective measures for improving habitat and biodiversity, which has the advantage of recovering ecosystems and biodiversity and promoting the formation of healthy rivers. Several applications of ERTs, including ecological water transfer, fish passage construction, dam removal/retrofit, channel reconfiguration, river geomorphological restoration, natural shoreline restoration, floodplain reconnection, revegetation, etc., are summarized. The classifications of ERTs are highlighted, aiming to distinguish the difference and relationship between structure and the processes of hydrology, physics, geography, and biology. The pros and cons of these technologies are discussed to identify the applicability and limitations on the river ecosystem. In the dynamic processes in the river, these interact with each other to keep ecosystem balance. ERTs are more helpful in promoting the restoration of the natural function of the river, which contribute to the management of river ecological health. Some proposals on river management are suggested. Establishing a unified river health evaluation system will help promote positive feedback on rivers and the further development of ERTs.

The high water content of waste-activated sludge restricts the subsequent disposal of sludge. The dehydration properties of O3, ferric chloride (FeCl3)/polyacrylamide, and sludge ceramsite sand (SCS) were studied. Simultaneously, the effect of combining the three was investigated to support the deep dehydration of waste-activated sludge. Experimental results showed that with13.42 mg/(g dry solids (DS)) of O3, 109.89 mg/(g DS) of FeCl3, and 100 mesh dosage of 70% DS of sludge ceramsite on weight, the highest sludge net yield was 7.13 kg/(m2·h) and the minimum specific resistance to filtration of sludge cake was 1.02 × 1012 (m/kg). Compared with the compressibility of the raw sludge, the compressibility of the sludge cake decreased by 37.48%. Moreover, the YN (net yield) increased by 73.55%. The results demonstrate that the structure of cracking, flocculation, and hydrophobic framework is the mechanism of sludge dewatering in this combined process. This combined treatment process provides a new perspective for the realization of deep dewatering of sludge and is anticipated to be a successful sludge dehydration method.

Dredging sea mud produced during the coastal infrastructure construction has been gradually becoming an environmental problem in China. Making ceramsite is an attractive way to convert the waste sea mud to resources used for many industrial sectors. However, the imapct of preheating and sintering conditions on the ceramsite properties and the biofilm formation capacity of the ceramsite are still poorly understood. This study aims to fill these knowledge gaps. Results suggested the optimal conditions for the preheating temperature was 350°C, the preheating time was 15 min, the sintering temperature was 1040°C, and the sintering time was 9 min. The dredging sea mud‐derived ceramsite showed better biofilm formation capacity with high COD and NH₄⁺‐N removal performance compared with the commercial ceramsites. The content of the chloride ion in the ceramist granules is close to zero, and the low cost of this material, implying this dredging sea mud‐derived ceramsite, could be an engineering favorable material for using it as a biocarrier in the real application.

The overgrowth of Microcystis aeruginosa (M. aeruginosa) often causes serious harm to the surface water environment. In recent years, allelopathic substances extracted from plants have been discovered to have inhibitory effects on algae growth. However, there is a scarcity of current studies on allelopathic extracts from terrestrial Asteraceae plants. This study investigated the inhibitory effect of Artemisia argyi (A. argyi) aqueous extract on the growth of M. aeruginosa. Gas chromatography-mass spectrometry was utilized to analyze the contents of A. argyi aqueous extracts, and their inhibitory effects and mechanisms were analyzed by measuring a series of indicators in algal cells. Results showed that terpenoids have the highest content in the A. argyi aqueous extract. Algal cells experienced severe oxidative damage and antioxidant reactions under the influence of A. argyi aqueous extracts, resulting in reduced photosynthetic capacity, enhanced membrane permeability, and intracellular fluid outflow. Furthermore, ecotoxicity experiments involving zebrafish and Vallisneria natans as experimental subjects demonstrated that A. argyi aqueous extract has good ecological safety. Therefore, A. argyi aqueous extracts can serve as a novel environmentally friendly algae inhibitor with potential practical applications for algae inhibition purposes.