Design And Experiment Of Water Hydrodynamic Purification Equipment In Aquaculture Ponds

With the continuous expansion of pond culture industry in China,the problem of river water pollution caused by improper treatment of pond water is becoming more and more serious,which seriously restricts the sustainable development of aquaculture.However,at present,most of the water quality treatment methods of aquiculture ponds in China are quite traditional,and hard to be popularized and used in a large area.However,the emergence of biological fence and biological flocculation technology can solve this kind of problems.However,the key to give full play to its effect is to form sufficient hydrodynamic force,while the hydrodynamic formation range of oxygen-increasing devices on the market are insufficient,and the energy consumption is large.In view of the above problems,this paper design an new equipment,which can improve the water exchange capacity,meantime make sure the basic oxygen increasing capacity.The main contents and achievements of this thesis are as follows:(1)Based on the research and investigation of the existing hydrodynamic devices on the market,this paper puts forward a kind of water power purification device for the ponds that lifting water,break water and push water into an organic whole,achieving the improvement of the water exchange efficiency on the premise that the same power consumption and oxygen enhancement effect is up to standard.Combined with its basic structure and function,an implementation scheme based on bidirectional kinetic energy output is designed,which makes use of the advantages of low rotation speed and low resistance of eccentric block in air and combine with water lifting and breaking impeller so that can guarantee the basic oxygen-increasing ability and form a large scale,three-dimensional hydrodynamic cycle at the same time.(2)In order to realize the functions of lifting water,breaking water and pushing water,the structure of double output deceleration box is designed,and the transmission ratio is determined to be 7: 176 and 26: 252,respectively.According to the requirements of hydrodynamic formation mode,1.5Kw three-phase AC motor with rotational speed of 1450r/min is determined as the power source.The eccentric block pendulum arm length is 380 mm,the counterweight is 10 kg,and the rated power of the device is 0.921 Kw.The key performance index of the device is verified,the detailed design of the device is perfected,the machining drawings are completed,and the mechanical structure subsystem is processed and basically tested.The test results show that the equipment can meet the requirements of the working conditions in the pond environment in terms of structural strength,water tightness and other key technical indicators.(3)According to the water quality of four big domestic fish culture ponds in Yangtze River Delta,the material and working principle of biofilm and flocculation were analyzed and compared,and biofilm combined with hydrodynamic forming device was selected to realize the purification of pond water quality.According to the characteristics of biological density and biological capacity in the culture pond,the trapezoid layout scheme was developed in combination with the hydrodynamic formation mode of the equipment.The effective length of biofilm is 1.2 m,the spacing of biofilm is 1.5 m,the total length of biofilm module is 84 m,and the relative application technology of biofilm system is established,and the counterweight calculation is carried out.(4)According to the operation requirements,the functional requirements of the control system are put forward,including the control board card,sensor,data storage and communication,motor drive and so on.The high power control circuit and the damp proof and wind-proof distribution box are designed.Assist in the development of the control board card and control logic design,combined with the implementation of the control system requirements for water quality data acquisition module,data transmission module,motor control module and so on joint debugging,According to the results of joint debugging,the design scheme of the control system is revised,and a preliminary comprehensive design scheme is formed.(5)The field test is carried out according to the design requirements of the equipment.In Guangde Anhui province,Shanghai Haifeng Aquaculture Cooperative,Guangming Group Dongfeng Culture,the key indexes such as hydrodynamic coverage,oxygen-increasing capacity,water purification effect and comprehensive energy consumption were tested in different stages.The first stage test shows that the flow velocity coverage area of the device is 8654.6m2,and the middle velocity coverage area is 615.4m2,which is 36.1% higher than that of the 3Kw impeller aerator.The oxygen increasing capacity is 2.67Kg/h,which reaches 66.7% of the oxygen increasing capacity of the 3Kw wheel type oxygen increasing machine.The second stage experiment showed that the power consumption per unit area decreased by 30.41% and the ammonia nitrogen index decreased by 20.52% on the 3-5mg/L dissolved oxygen index.The Shannon-Wiener index and the composition of the dominant population in the pond were all improved.