Study On High Temperature Treatment And Plants Uptake Of Pond Aquaculture Sediments

Pond farming is the way of aquaculture in China.In 2019,the national production of pond farming exceeded 24.8 million tons,and the trend is increasing year by year.Because farming enterprises’ pursuit of pond breeding of high yield and neglect of water for aquaculture environment,for the accumulation of a large number of baits,excrement and animal and plant debris caused water pollution,and damaged aquaculture production and ecological environment problems,with the worsening of breeding environment,there are more and more study on aquaculture sediments both at home and abroad.There are many ways to dispose sediments.However,there are still some deficiencies in high temperature treatment and absorption and transformation of economic plants.In this paper,selecting typical pond culture sediments as the research object,the removal effects of high temperature treatment and absorption of plants(maize)on the nutrients of sediments were studied.The main research results are as follows:1.The burning temperature was set at 150℃,300℃,450℃ and 600℃respectively,and the burning time was 5s,10 s and 20 s respectively for the removal of nitrogen and phosphorus in the sediments.The results showed that the removal rate of nitrogen and phosphorus in sediments gradually increased with the increase of temperature.When the burning temperature reached 600℃,the removal rates of TN and TP in sediments could reach 70% and 55% respectively.At the same temperature,with the increase of burning time,the removal rate of nitrogen and phosphorus in the sediments gradually increased,and the removal rate reached the maximum at 20 s,in which the removal rate of TN and TP were 50% and 45% respectively,indicating that high temperature burning can effectively remove nutrients such as nitrogen and phosphorus from pond culture sediments.2.In order to understand the properties of the overlying water of the sediments after high temperature treatment,the changes of inorganic nitrogen and phosphorus concentrations in the overlying water of the sediments were studied and analyzed at different temperatures and time.It was found that the tri-state nitrogen in the overlying water was the lowest when the burning temperature was 450℃.The burning temperature was 600℃,and the concentration of TOC in the overlying water was the lowest.When the burning time was 20 s,the concentration of the tri-state nitrogen and TOC in the overlying water were the lowest.At the same time,it was found that the concentration of SRP in the overlying water increased with the increase of the burning temperatures and the burning time reached the highest concentration at 600℃ and20 s,respectively.In addition,the influence of high temperature cauterization on the bacterial flora in pond culture sediments was also studied.It was found that there were a large number of bacteria in pond sediments,including coliform and fecal coliform bacteria.After high temperature cauterization,all bacteria in the sediments could be killed,indicating that high temperature cauterization could effectively remove bacteria in the sediments.3.Three kinds of maize were selected to study the absorption of nitrogen and phosphorus in pond aquaculture sediments.The results showed that the average absorption and utilization rate of TN and TP in the sediments of the three kinds of maize reached 80% and 70% respectively,and the height of the three kinds of maize reached 145.3cm,138.4cm and 135.2cm,respectively.Were significantly lower than field maize height(P<0.05),the ear length of the three kinds of maize was 8.4cm,7.5cm,8.2cm,respectively,which was also significantly lower than the average length of field corn(P<0.05),indicating that the cultivation of maize in the aquaculture sediments can better absorb the inorganic nitrogen,inorganic phosphorus and other nutrients in the aquaculture sediments,although the growth condition is not as good as that of field planting,but it is still an effective way to remove.In conclusion,high temperature cauterization and maize planting can effectively remove nitrogen,phosphorus and other nutrients in pond sediments,and kill bacteria in sediments.This study provides a reference for efficient treatment and resource utilization of pond sediments.