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The phosphorus reduction in water column was attempted by integrating sediment microbial fuel cells (SMFCs) with the submerged macrophyte Vallisneria spiralis. A comparative study was conducted to treat simulated water rich in phosphate with a control and three treatments: SMFC alone (SMFC), submerged macrophytes alone (macophyte), and combined macrophytes and fuel cells (M-SMFC). All treatments promoted phosphorus flux from the water column to sediments. Maximum phosphorus reduction was obtained in proportion to the highest stable phosphorus level in sediments in M-SMFC. For the initial phosphate concentrations of 0.2, 1, 2, and 4 mg/L, average phosphate values in the overlying water during four phases decreased by 33.3% (25.0%, 8.3%), 30.8% (5.1%, 17.9%), 36.5% (27.8%, 15.7%), and 36.2% (0.7%, 22.1%) for M-SMFC (macrophyte, SMFC), compared with the control. With macrophyte treatment, the obvious phosphorus release from sediments was observed during the declining period. However, such phenomenon was significantly inhibited with M-SMFC. The electrogenesis bacteria achieved stronger phosphorus adsorption and assimilation was significantly enriched on the closed-circuit anodes. The higher abundance of Geobacter and Pseudomonas in M-SMFC might in part explain the highest phosphorus reduction in the water column. M-SMFC treatment could be promising to control the phosphorus in eutrophic water bodies.

Six wetland plants were investigated for their effect on the degradation characteristics of chlorpyrifos in nonsterile hydroponic system at constant temperature of 28 degrees C. The results showed that the removal rates of chlorpyrifos in the water of plant systems were 1.265.56% higher than that in the control without plants. Scirpus validus and Typha angustifolia were better than other hygrophytes in elimination of chlorpyrifos. The removal rates of the two systems were up to 88%. Plants of acaulescent group had an advantage over caulescent group in removing chlorpyrifos. Phytoaccumulation of chlorpyrifos was observed, and the order of chlorpyrifos concentration in different plant tissues was root > stem > leaf. It was also found that chlorpyrifos and its metabolite TCP decreased rapidly at the initial step of the experiment.

Phosphorus is a crucial element in the eutrophication process. According to China’s water pollutant discharge Class 1A standard, treated wastewater must meet 0.5 mg/L of phosphorus prior to discharge to a sensitive water body. In recent years, wastewater treatment technologies such as membrane bioreactors have been demonstrated to achieve high-quality effluent and present the potential for wastewater reuse applications. However, an efficient and cost-effective phosphorus removal process is still not warranted. In this study, a submerged membrane bioreactor (SMBR) with addition of a low concentration of aluminum sulfate ([mol Al : mol P ≤ 1] was used to evaluate its treatment performance. The results showed that significant phosphorus removal could be achieved with addition of a low aluminum sulfate dosage to meet national phosphorus discharge standard; however, no significant effect was observed on the removal of COD and ammonia. The addition of a low concentration of aluminum sulfate could offer as an economical solution to increase the phos phorus removal efficiency of a SMBR, and thereby improve the water quality of the water bodies.