Study On The Role Of Aquatic Plants And Microorganisms In The Advanced Treatment Of Saline Wastewater

Among the discharged water bodies,salt-containing wastewater(referring to wastewater containing a large amount of inorganic salts)has become a type of sewage that cannot be ignored.It has a wide range of sources,contains many types of pollutants and complex components,which will seriously threaten the safety of the water environment.Balance of aquatic,terrestrial and wetland ecosystems.Therefore,this article takes saline wastewater as the treatment object,and uses aquatic plants combined with microorganisms and other microorganisms to simulate small-scale constructed wetland systems to carry out simulation experiments on the purification effects of typical pollutants(pollutants such as nitrogen and phosphorus nutrients).Analyzed under different conditions(1、the system stopped entering a certain amount of water;2、the system continued to enter and exit)to observe and study the purification ability of different plant species,hydraulic loads,salt gradients and other factors on wastewater purification.This research mainly draws the following conclusions:1、Adopt a fixed water inlet method(stop the water inlet after entering a certain amount of wastewater),and it is found when treating(EC=5000μs/cm)salty wastewater.In general,in the nearly 4 days of experimentation,it was found that the COD removal ability of the three kinds of plants for this kind of wastewater was average,but the three had the best removal effect compared to water hyacinth.The water hyacinth group has the highest removal rate of NH3-N up to 99%;followed by water hibiscus and small duckweed with only44% and 33% removal rates.Except for water hyacinth,TP has obvious removal effect,and the other two groups have basically no effect.Among the three kinds of floating water plants,the comprehensive treatment effect of water hyacinth is the best,and the treatment effect of small duckweed is the worst.For emergent plants(canna,iris and cattail),it was found in experiments that the three plant groups have good treatment effects on pollutants in the water.In the same residence time,the The COD removal effect is the best;for NH3-N,canna and iris have good treatment effect;and for TP,canna and cattail have the best removal effect.The submerged plant Hydrilla verticillata can grow normally in salty wastewater under different salinity gradients.The removal ability of COD and TP in water is average,and it has good treatment effects on NH3-N and TN.2.It was found when using continuous water inflow and continuous water discharge,and it was found when treating salty wastewater with EC of 5000μs/cm,10000μs/cm and15000μs/cmThree aquatic plants have a strong ability to remove pollutants in 5000μs/cm industrial wastewater.Among them,the emergent plant canna has a strong comprehensive purification ability,and the purification ability from strong to weak is canna,yellow iris,and cattail..In the industrial wastewater with an influent of 5000μs/cm,canna and iris have the best purification effect on NH3-N,and canna has the best purification effect on TN.Typha latifolia and Iris candidum have their own emphasis.The former has a strong ability to remove total phosphorus,and the latter has a strong ability to remove ammonia nitrogen.From the perspective of the plant itself,the roots of canna and iris are dense and slender,and the intricate intersection between the roots also has a good filtering effect.In addition to specific pollution factors in sewage,specific aquatic plants can be selected.The three aquatic plants have their own advantages,and the removal effect is better with reasonable configuration.The three plants still have a certain removal effect on NH3-N and TP in wastewater with conductivity of 5000μs/cm,10000μs/cm and 15000μs/cm.Under the three salinity gradients,the removal effect of the three plants on ammonia nitrogen was basically unaffected,but the effect on the removal effect of TP was more obvious,and the removal effect gradually weakened with the increase of salinity.In wastewater with a conductivity of 15000μs/cm or less,from the perspective of growth,the canna leaves were found to wither first,followed by yellow iris.However,the growth status of the cattail itself is basically not affected.Although the cattail is relatively salt-tolerant,it is not easy to plant in the early stage and is prone to blackworm disease.It can be seen that the salt tolerance of three aquatic plants is: cattail> yellow iris> canna.