脱二氧化碳装置对循环水养殖系统pH的影响

为了调节循环水系统中养殖水体的pH,根据气体交换原理,设计一种脱二氧化碳(CO_2)装置。采用该装置去除养殖水体中的CO_2,并对由于CO_2含量累积造成的pH下降进行调节,使养殖鱼类处在一个适宜的pH环境中。试验时水温控制在(25±0.5)℃,每1 h取水样测1次pH,每4 h测1次碱度。水样取自养鱼桶内的水,检测前先对水样用40μm孔径针头过滤器进行过滤处理,实验周期24 h。结果显示,循环水系统加装脱二氧化碳装置能有效去除CO_2,使水体稳定在一个适宜的pH范围(7.39~7.42);CO_2质量浓度呈降低趋势,24 h后由开始的13.16 mg/L降低到7~8 mg/L,降低近50%,而不加装脱二氧化碳装置的循环水系统CO_2质量浓度持续上升,24 h后增加到37 mg/L左右,pH持续降低,最终降低到6.72~6.81。研究表明,脱二氧化碳装置能够有效去除水体中的CO_2,使水体pH维持在一个适宜鱼类生长的范围。

The effect of carbon dioxide removal device on pH level of recirculating aquaculture system

In order to regulate the water pH level in recirculating aquaculture system (RAS),a CO2 removal device was designed based on gas exchange principle and tested,in the wish to remove CO2 from aquaculture water and adjust the pH drop caused by CO2 accumulation,so that the cultured fish would live in a suitable pH environment.During the test,water temperature was controlled at (25 ± 0.5) ℃,pH was measured every hour, and alkalinity was measured every 4 hours;water samples were taken from barrels culturing fish and were filtered with 40μm syringe filter before detection;the experimental cycle was 24 h.The results showed that the installation of the CO2 removal device in RAS could effectively remove CO2 in the water body and stabilize the water pH level within a suitable range between 739-742;the CO2 concentration exhibited a decreasing trend,and after 24 h it reached 7-8 mg/L from the initial 13.16 mg/L,decreased by nearly 50%;while in the recirculating water system without the CO2 removal device, CO2 content continued to increase and reached 37 mg/L after 24 h, meanwhile the pH level continued to decrease and finally to 6. 72~6. 81. The research shows that the CO2 removal device can effectively remove CO2 in the water of RAS and maintain the pH level at a suitable range for fish growth.