Research and application status of ecological floating bed in eutrophic landscape water restoration.

Ecological floating bed (EFB) has become the preferred technology due to its reputation of green economy, convenience, and efficiency in treating eutrophic landscape water. Based on the statistical analysis of abundant literatures, this paper systematically summarizes the component elements, design parameters, purification mechanism, purification ability, strengthening methods and the correlations among various parameters of EFB, and points out some issues existing in the current research and applications. The results show that the coverage of 5% ~ 38% and water depth of 60 ~ 110 cm should be recommended for EFB design.

Impact of calcium peroxide dosage on the control of nutrients release from sediment in the anoxic landscape water.

The anoxic and reductive aquatic environment is formed easily in summer due to the global warming, which may accelerate endogenous release. In this experiment, four different dosages of calcium peroxide (CaO) were adopted to study the control effects of nutrients release from the sediments in the simulated landscape waters. The results demonstrated that CaO addition could effectively improve the physicochemical properties and microbial composition in sediments, and an obvious improvement was achieved with a larger dosage.

Dose effects of calcium peroxide on harmful gases emissions in the anoxic/anaerobic landscape water system.

Large-area hypoxia of urban landscape water often causes the emissions of harmful gases in summer, which not only reduces its sensory effects, but also brings a potential threat to aquatic ecosystem and human health. This study explored the dose effects of calcium peroxide (CaO) on inhibiting harmful gases emissions and restoring the scenic effect (including visual sense and olfactory sense) of anoxic/anaerobic landscape water system. The results indicated that the emissions of HS, CO and CH from the anoxic/anaerobic water system were obviously inhibited in the reactors with CaO additions and the effect was positively correlated with the CaO dose.

Effect of calcium peroxide on the water quality and bacterium community of sediment in black-odor water.

This study investigated how efficiently CaO could treat black-odor landscape water caused by low dissolved oxygen (DO) in a field experiment of 600 m. The study demonstrated that CaO could significantly elevate the DO concentration in waters and the oxidation-reduction potential (ORP) level in sediments (p = 0.003 and p = 0), which is conducive to improving the anoxic environment of landscape water.

Effect of a strengthened ecological floating bed on the purification of urban landscape water supplied with reclaimed water.

A floating bed (FB) system vegetated with calamus, iris, lythrum, and Hydrocotyle vulgaris, and a strengthened FB (SFB) system with zeolite and sponge iron as fillers were simultaneously applied to purify urban landscape water in different zones. The urban landscape water, an artificial lake of approximately 326m, was supplied with reclaimed water during a six-month experiment. Results indicated that the concentrations of nitrogen (N) and phosphorus (P) in the SFB zone (SFBZ) were significantly lower than those in the control zone (CZ) and the FB zone (FBZ) after six months of operation.