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Abstract Although Myriophyllum aquaticum exhibits efficient nitrogen and phosphorus removal from wastewater, it has poor performance on organic matter removal. Here, a wastewater treatment system combining M. aquaticum and activated sludge was developed to improve its removal of organic matter. The Box–Behnken response surface methodology was used to optimize the construction conditions of the system, and the effects of time, temperature, illumination intensity, pollutant load, and dissolved oxygen (DO) on plant mass increment (PMI) and microbial biomass (MB) of the system were investigated. The wastewater remediation potential of the system was then evaluated. The results show that temperature and illumination intensity significantly affected PMI (p < 0.01), and that time, pollutant load, and DO were the most significant factors affecting MB (p < 0.01). The optimal construction conditions were 18.77 days in length, a temperature of 20.42 °C, an illumination intensity of 5827.61 Lx, a pollutant load of 120.61 mg/g plant, and a DO of 3.21 mg/L. The inoculation of activated sludge caused MB of the system to increase by four times relative to the non-inoculated system, suggesting successful formation of biofilms on M. aquaticum. Additionally, the removal of chemical oxygen demand (COD) from wastewater was significantly enhanced by the combined approach compared with a system relying solely on M. aquaticum. This study provides a new method for improving the remediation efficiency of M. aquaticum by combining the use of this species and activated sludge. Highlights • A system was constructed by the combined use of M. aquaticum and activated sludge. • Response surface methodology was used for optimizing system conditions. • Biofilm attached onto was successfully M. aquaticum formed. • Organic matter removal potential by the system was significantly enhanced. [ABSTRACT FROM AUTHOR]

The aim of this research was to assess the applicability of Myriophyllum ( M. ) aquaticum for swine wastewater treatment. Nitrogen (N) removal processes were investigated in M. aquaticum mesocosms with swine wastewater (SW), 50% diluted swine wastewater (50% SW), and two strengths of synthetic wastewater, 200 mg NH 4 + - N L −1 (200 NH 4 + - N ) and 400 mg NH 4 + - N L −1 (400 NH 4 + - N ). During a 28-day incubation period, the average NH 4 + - N and TN removal rates were 99.8% and 94.2% for 50% SW and 99.8% and 93.8% for SW, which were greater than 86.5% and 83.7% for 200 NH 4 + - N , and 73.7% and 74.1% for 400 NH 4 + - N , respectively. A maximum areal total nitrogen (TN) removal rate of 157.8 mg N m −2 d −1 was found in M. aquaticum mesocosms with SW. During the incubation period, the observed dynamics of NO 3 − - N concentrations in water and gene copy numbers of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), nirK and nirS in soil unraveled strong nitrification and denitrification processes occurring in M. aquaticum mesocosms with swine wastewater. The N mass balance analysis indicated that plant uptake and soil N accumulation accounted for 17.9–42.2% and 18.0–43.8% of the initial TN load, respectively. The coupled nitrification and denitrification process was calculated to account for, on average, 36.8% and 62.8% of TN removal for 50% SW and SW, respectively. These findings demonstrated that the N uptake by M. aquaticum contributed to a considerable proportion of N removal. In particular, the activities of ammonia-oxidizing and denitrification microbes responsible for nitrification and denitrification processes in M. aquaticum mesocosm accelerated NH 4 + - N and TN removal from swine wastewater. [ABSTRACT FROM AUTHOR]

The present study assessed the reduction of nutrients and organic matter in polluted waters using Myriophyllum aquaticum. Twelve experimental groups were established and distributed in six control groups (CG) and six plant treated groups (PTG). The following analyses were performed in three sampling sets and measured every three days: chemical oxygen demand (COD), biochemical oxygen demand (BOD), ammoniacal nitrogen (AN), organic nitrogen (ON), total Kjeldahl nitrogen (TKN), and total phosphorus (TP). Dissolved oxygen (DO), pH, electrical conductivity (EC), and temperature (TEMP). The parameters that showed variation between the experimental groups were dissolved oxygen (0.1–5.0 mg L−1), pH (7.5–8.5), electrical conductivity (550–750 μS cm−1), and temperature (15–19 °C). The highest level of removal was observed on day 30 as 75.4% for BOD; 67.4% for COD; 88.3% for TKN; and 93.6% for TP. The use of M. aquaticum demonstrated its potential application in phytoremediation, showing reductions in COD, BOD, and TP at day 15, and in AN and TKN at day 30. [Copyright &y& Elsevier]