6种水生植物腐烂过程中水质理化指标的变化室内模拟研究

The Indoor Simulation Study on Change of Physical and Chemical Indicators of Water Quality during Decomposition Process of Six Kinds of Aquatic Plants

为了研究各类水生植物腐烂过程中产生的营养盐对石佛寺人工湿地水体水质的持续影响,在室内模拟4类6种水生植物[漂浮植物槐叶苹(Salvinia natans)、浮水植物丘角菱(Trapa japonica)、挺水植物水烛(Typha angustifolia)和荷花(Nelumbo nucifera)、沉水植物选择穗状狐尾藻(Myriophyllum spicatum)和金鱼藻(Ceratophyllum demersum)]的腐烂过程。漂浮植物和浮水植物组、挺水植物组、沉水植物组都进行了加底泥与不加底泥实验,沉水植物组同时还进行了不同生物量植物腐烂过程对比研究。测定的指标包括水温、水体p H和水中的溶解氧含量、化学需氧量含量、总氮含量、总磷含量以及底泥的全氮、全磷和有机质含量。研究结果表明,漂浮植物、浮水植物和沉水植物最易腐烂,挺水植物相对腐烂较慢,沉水植物腐烂、分解最彻底,植物生物量越大,其腐烂时释放的营养物质越多;放置同类植物实验桶内水的p H变化规律相同,加底泥与否不影响水的p H变化规律,挺水植物实验组水中的溶解氧含量变化规律与其它实验组不同,主要与植物内部结构组织有关;挺水植物在腐烂过程中,释放有机物的过程最漫长,且释放量较大,底泥不影响水中总氮含量的变化规律,但影响水中总氮的含量;在漂浮植物、浮水植物和挺水植物腐烂过程中,其向水中释放磷的速率高于沉水植物,是否加底泥和植物生物量能影响水中总磷含量,磷在水体和底泥之间存在明显的吸附、沉淀和迁移现象。在湖泊管理过程中,应减少向湖泊系统中输入过多的能量,及时清理湖中的底泥,以避免造成水体二次污染。

The continued effects of all kinds of aquatic plant decomposition on water quality of the Shifosi constructed wetlands were evaluated using an indoor simulation experiment, in which there were 4 groups [group of flotage plant（Salvinia natans） and floating plant（Trapa japonica）; group of emerged plants（Typha angustifolia and Nelumbo nucifera）; group of submerged plant（Myriophyllum spicatum and Ceratophyllum demersum）;control group], aquatic plants on nutrient releasing were examined during the decomposition process. The comparative experiments with sediment and without sediment for 4 groups, and with different biomass for the submerged plant group were carried out during the decomposition process of plants. The determination indicators of water quality were water temperature, p H, and contents of dissolved oxygen, chemical oxygen demand,total nitrogen, total phosphorus; those in sediments were total nitrogen, total phosphorus and organic matter contents. Compared with flotage plant, floating plant, submerged plants and emerged plants were undergoing the slowest decomposition; while, the most thoroughly decomposed plants were the submerged plants, in addition, the amount of nutrients that were released corresponds to the biomass of the plants, the more was larger.There were correlation relationships between the p H of water body with plants of same life forms, and the sediment would not affect the p H of water body. The content of dissolved oxygen in the water with emerged plants showed a different trend compared with the other groups, the internal structure of the plant organization was the main cause. The organics releasing process of emerged plant was longer, the sediment would not affect the content of total nitrogen in the water, but the amount. Total phosphorus contents in the water with flotage plant, floating plant and emerged plants were higher than that with submerged plants. The sediment and plant biomass could affect the concentration of total phosphorus in the water. Reduce excessive energy input into the wetlands and clear sediment timely to avoid the secondary pollution of the water body.