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A batch of biochar was produced from pyrolysis of Typha angustifolia (TBCs) at 200-500℃ for 2 h and 6 h to investigate the effects of pyrolytic temperature and heating retention time on the physico-chemical properties. Moreover, Escherichia coli ( E. coli ) HB101 and the seeds of Helianthus annuus were used to preliminarily test the ecological risk of the TBCs. Results showed that the heating retention time (i.e., 2 and 6 h) had no significant effect on the properties of TBCs, while pyrolytic temperature significantly affected TBCs' characteristics. As the pyrolysis temperature increased from 200 to 500℃, the mass yield and contents of hydrogen (H) and oxygen (O) decreased, while the contents of carbon (C) and ash increased. The pH and surface pores also increased with increasing pyrolytic temperature, whereas the O-containing functional group (e.g., -COOH and -OH) decreased. These results indicated the increased carbonization and aromatization of the TBCs. For the inherent nutrients of TBCs, the total phosphorus (TP) and available potassium (K) contents significantly increased as temperature increased. The main components of dissolved organic matter (DOM) of TBCs were humic acid-like and fulvic acid-like organic compounds. As the pyrolysis temperature increased, the content of humic acid-like organic compounds decreased, while the content of fulvic acid-like organic compounds increased. All the TBCs had no significant effect on the growth of E. coli HB101 and the seed germination of Helianthus annuus , indicating the little ecological risk of TBCs under the experimental conditions. These findings provide an alternative way for resource utilization of waste wetland biomass and provide important theoretical data for screening biochar in soil reclamation.

Nitrogen removal in constructed wetlands (CWs) is highly affected by the supply of organic carbon. Thus, to enhance nitrogen removal in the horizontal subsurface flow of CWs, plant carbon sources were added during the downstream portion of the wetland. Moreover, the characteristics of static release and the denitrification potential of Typha were evaluated using three different pretreatment methods (i.e., minced, acid-heated, and alkali-heated). The average concentrations of COD released and the nitrate removal rate with the alkali-heated, acid-heated, and minced Typha were 89.57 mg·L -1 and 75.2%, 67.27 mg·L -1 and 67.2%, and 54.45 mg·L -1 and 23.5%, respectively. The results showed that different pretreatment methods resulted in the release of different amounts of acetic acid, and the alkali-heated Typha performed much better than the other pretreatments. Therefore, the alkali-heated Typha was selected and added to the middle of the horizontal subsurface flow CW, which improved the nitrogen-removal rate significantly; the average removal rate of TN and TP was higher than that of a control CW by 30.3% and 33.9%, respectively. However, the COD concentration of the CW with the alkali-heated Typha was not significantly increased.

To reveal the correlation between plant communities and soil chemical factors (pH, the total amount of soil soluble salt, TN, TP, SOM, K + , Na + , Ca 2+ , Mg 2+ , Cl - , SO 4 2- , HCO 3 - ) in Shandong coastal saline area, a field investigation of 81 samples was carried out and the chemical properties of the soil were analyzed. The results showed that a total of 85 species, 67 genera and 30 families of salt-tolerant plants were recorded. The top three dominant families were Compositae, Gramineae and Chenopodiaceae. The community could be divided into four types: Phragmites aus-tralis - Imperata cylindrical + Artemisia capillaris, Suaeda salsa + P. australis - A. capillaris + Kochia scoparia, P. australis - Typha orientalis + Apocynum venetum, P. australis - A. venetum. The CCA sequencing results showed that the soil total soluble salt and water-soluble ions were the key chemical factors affecting the distribution of salt-tolerant vegetation, followed by total nitrogen content. The community of P. australis - I. cylindrical + A. capillaris had richest species diversity among the four community types, and the resources of salt-tolerant plants were abundant. The species diversity of plant community showed a significant negative correlation with soil total soluble salts and water soluble salt ions content. The plant community diversity index would be reduced by the high saline soil.

To evaluate the feasibility of using multi-soil-layer (MSL) system and subsurface flow constructed wetland to treat the wastewater of marine cultured Penaeus vannamei and to determine the suitable process for the local aquaculture wastewater pollution characteristics. In this study, MSL system and four constructed wetland systems with Spartina anglica, Phragmites australis, Typha latifolia and unplanted system were evaluated for their potentials of pollutants removal capacity. The results showed the average removal rates of chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), ammonia nitrogen (NH(4)+ -N) and nitrate (NO-(3) -N) by MSL system were 80. 38% ± 2. 14% , 68. 14% ± 3.51% , 40.79% ± 3. 10% , 42. 68% ± 2.90% and 54. 19% ± 5. 15% , respectively. Additionally, the ability of pollutants removal of other four wetland systems decreased in the order: Spartina anglica, Phragmites australis, Typha latifolia and unplanted system.