低功率密度超声波强化絮凝沉降除藻技术研究
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摘要
超声波强化絮凝沉降除藻技术能够提高絮凝沉降除藻效率,但以往研究采用的较高超声波功率限制了这一组合技术的应用。通过探究低功率密度超声波(0.5～1.0 W/L)对絮凝沉降技术去除微囊藻的增效作用,比较了增重剂种类及用量、超声波预处理的时间和距离、超声波预处理与絮凝沉降的间隔时长、日光照射时长等因素对除藻率的影响,并通过水池试验验证了低功率密度超声波的增效作用。结果显示:(1)超声波的处理距离对除藻率无显著影响,但增加超声波预处理时长则明显有利于提高除藻率,处理30 s时的除藻率显著高于仅处理10 s时的除藻率;(2)除藻率的日均变幅较大,当日光光照时长为3～9 h时,试验组的除藻率平均比对照组高17%,日光照射时长为0 h和12 h时,试验组与对照组的除藻率则无显著差异;(3)随着超声波预处理与絮凝沉降间隔时长的增加,除藻率会明显下降,仅当间隔时长不超过30 min时,试验组的除藻率才显著高于对照组;(4)水池原位试验中,试验组的除藻率高达70.47%,显著高于对照组的58.12%。研究表明,低功率密度超声波预处理能明显增加絮凝沉降除藻率,且应在日光开始减弱的下午作业。
Ultrasound enhanced flocculation is efficient for algae-control, but the high power density required for ultrasound treatment prevents wide application. In this study, low power density ultrasound(LPDU, 0.5-1.0 W/L) enhanced flocculation was used to remove wild Microcystis aeruginosa. The treatment parameters were optimized, including the coagulation agent and dose, duration and distance of ultrasonic treatment, time interval between ultrasonic treatment and flocculation, and illumination duration. A pilot test was carried out in a pond to determine the algae removal efficiency achieved by LPDU enhanced flocculation. Five findings are reported:(1) The type and dosage of coagulation agents has a significant effect on algae-removal efficiency. The highest algae-removal efficiency was obtained by using 11-22 g/L of loess(mesh 40-80) or quartz sand(mesh 120-200).(2) Algae removal was not affected by the distance of ultrasonic treatment, but increased with treatment time, and the algae-removal efficiency with 30 s of ultrasonic treatment was significantly higher than with 10 s(P<0.05).(3) Algae-removal efficiency was closely related to sunlight duration; removal efficiency was 17% higher in the treatment group, compared to the control, when sunlight duration was 3-9 h(P<0.05), while no significant difference was observed between treatment group and control when the sunlight duration was 0 h or 12 h(P>0.05).(4) Algae-removal efficiency decreased with increased time between ultrasonic treatment and flocculation; removal efficiency was significantly higher when the interval did not exceed 30 min(P<0.05).(5) In the in situ pond experiment, the algae-removal efficiency with LPDU(70.47%) was significantly higher than the control(58.12%). These results show that LPDU treatment significantly improves algae-removal efficiency and that afternoon is the best time for removing Microcystis blooms using LPDU enhanced flocculation.
Ultrasound enhanced flocculation is efficient for algae-control, but the high power density required for ultrasound treatment prevents wide application. In this study, low power density ultrasound(LPDU, 0.5-1.0 W/L) enhanced flocculation was used to remove wild Microcystis aeruginosa. The treatment parameters were optimized, including the coagulation agent and dose, duration and distance of ultrasonic treatment, time interval between ultrasonic treatment and flocculation, and illumination duration. A pilot test was carried out in a pond to determine the algae removal efficiency achieved by LPDU enhanced flocculation. Five findings are reported:(1) The type and dosage of coagulation agents has a significant effect on algae-removal efficiency. The highest algae-removal efficiency was obtained by using 11-22 g/L of loess(mesh 40-80) or quartz sand(mesh 120-200).(2) Algae removal was not affected by the distance of ultrasonic treatment, but increased with treatment time, and the algae-removal efficiency with 30 s of ultrasonic treatment was significantly higher than with 10 s(P<0.05).(3) Algae-removal efficiency was closely related to sunlight duration; removal efficiency was 17% higher in the treatment group, compared to the control, when sunlight duration was 3-9 h(P<0.05), while no significant difference was observed between treatment group and control when the sunlight duration was 0 h or 12 h(P>0.05).(4) Algae-removal efficiency decreased with increased time between ultrasonic treatment and flocculation; removal efficiency was significantly higher when the interval did not exceed 30 min(P<0.05).(5) In the in situ pond experiment, the algae-removal efficiency with LPDU(70.47%) was significantly higher than the control(58.12%). These results show that LPDU treatment significantly improves algae-removal efficiency and that afternoon is the best time for removing Microcystis blooms using LPDU enhanced flocculation.
引文
陈卫,盛誉,曹吉吉,等,2011. 超声波强化混凝处理太湖高藻水效能研究[J]. 华中科技大学学报(自然科学版),39(1):110-113.
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董敏殷,乔俊莲,王国强,等,2008. 低频超声波对藻毒素释放和降解的研究[J]. 净水技术,27(6):21-23.
范帆,李文朝,柯凡,2013. 巢湖市水源地铜绿微囊藻(Microcystis aeruginosa)藻团粒径时空分布规律[J]. 湖泊科学,25(2):213-220.
刘德富,杨正健,纪道斌,等,2016. 三峡水库支流水华机理及其调控技术研究进展[J]. 水利学报,47(3) :443-454.
刘国锋,钟继承,张雷,等,2009. 有机改性粘土对铜绿微囊藻的絮凝去除[J]. 湖泊科学,21(3):363-368.
刘鸿亮,1987. 湖泊富营养化调查规范[M]. 北京:中国环境科学出版社:227-229.
陆贻超,王国祥,李仁辉,2010. 超声波和改性粘土集成技术在去除蓝藻水华上的应用[J]. 湖泊科学,22(3):421-429.
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向斯,刘世昌,程凯,等,2015. pH值及黏土密度对壳聚糖改性絮凝剂除藻效果的影响[J]. 中国环境科学,35(5):1520-1525.
肖艳,甘南琴,郑凌凌,等,2014. 光强对微囊藻群体形态的影响及其生理机制研究[J]. 水生生物学报,38(1):36-42.
张艳晴,杨桂军,秦伯强,等,2014. 光照强度对水华微囊藻(Microcystisflos-aquae)群体大小增长的影响[J]. 湖泊科学,26(4):559-566.
张永生,孔繁翔,于洋,等,2010. 蓝藻伪空胞的特性及浮力调节机制[J]. 生态学报,30 (18):5077-5090.
张永生,李海英,孔繁翔,等,2011. 群体细胞间空隙在微囊藻水华形成过程中的浮力调节作用[J]. 环境科学,32(6):1603-1607.
邹华,潘纲,阮文权,2007. 壳聚糖改性粘土絮凝除藻的机理探讨[J]. 环境科学与技术,30(5):8-13.
邹华,潘纲,程子波,2009. 粘土原位除藻技术研究[J]. 环境科学,30(2):407-410.
朱宸,丁凯耘,丛海兵,等,2015. 水质安全的动态超声波强化混凝除藻水处理试验研究[J].环境科学学报,35(8):2429-2434.
Hayes P K,Walsby A E,1984. An investigation into the recycling of gas vesicle protein derived from collapsed gas vesicles[J]. Journal of General Microbiology, 130:1591-1596.
Otero A, Vincenzini M, 2003. Extracellular polysaccharide synthesis by Nostoc strains as affected by N source and light intensity[J]. Journal of Biotechnology, 102(2):143-152.
Walsby A E,1988. Homeostasis in buoyancy regulation by planktonic cyanobacteria[M]. FEMS Symposium, 44: 99-116.
Zhang G M, Zhang P Y, Fan M H, et al, 2009. Ultrasound-enhanced coagulation for Microcystis aeruginosa removal[J]. Ultrasonics Sonochemistry, 16(3):334-338.
储昭升,庞燕,郑朔芳,等,2008. 超声波控藻及对水生生态安全的影响[J]. 环境科学学报,28(7):1335-1339.
董敏殷,乔俊莲,王国强,等,2008. 低频超声波对藻毒素释放和降解的研究[J]. 净水技术,27(6):21-23.
范帆,李文朝,柯凡,2013. 巢湖市水源地铜绿微囊藻(Microcystis aeruginosa)藻团粒径时空分布规律[J]. 湖泊科学,25(2):213-220.
刘德富,杨正健,纪道斌,等,2016. 三峡水库支流水华机理及其调控技术研究进展[J]. 水利学报,47(3) :443-454.
刘国锋,钟继承,张雷,等,2009. 有机改性粘土对铜绿微囊藻的絮凝去除[J]. 湖泊科学,21(3):363-368.
刘鸿亮,1987. 湖泊富营养化调查规范[M]. 北京:中国环境科学出版社:227-229.
陆贻超,王国祥,李仁辉,2010. 超声波和改性粘土集成技术在去除蓝藻水华上的应用[J]. 湖泊科学,22(3):421-429.
唐林森,陈进,黄薇,等,2007. 湖泊等封闭及半封闭性水体水华治理方法[J]. 长江科学院院报,24(6) :39-41.
向斯,刘世昌,程凯,等,2015. pH值及黏土密度对壳聚糖改性絮凝剂除藻效果的影响[J]. 中国环境科学,35(5):1520-1525.
肖艳,甘南琴,郑凌凌,等,2014. 光强对微囊藻群体形态的影响及其生理机制研究[J]. 水生生物学报,38(1):36-42.
张艳晴,杨桂军,秦伯强,等,2014. 光照强度对水华微囊藻(Microcystisflos-aquae)群体大小增长的影响[J]. 湖泊科学,26(4):559-566.
张永生,孔繁翔,于洋,等,2010. 蓝藻伪空胞的特性及浮力调节机制[J]. 生态学报,30 (18):5077-5090.
张永生,李海英,孔繁翔,等,2011. 群体细胞间空隙在微囊藻水华形成过程中的浮力调节作用[J]. 环境科学,32(6):1603-1607.
邹华,潘纲,阮文权,2007. 壳聚糖改性粘土絮凝除藻的机理探讨[J]. 环境科学与技术,30(5):8-13.
邹华,潘纲,程子波,2009. 粘土原位除藻技术研究[J]. 环境科学,30(2):407-410.
朱宸,丁凯耘,丛海兵,等,2015. 水质安全的动态超声波强化混凝除藻水处理试验研究[J].环境科学学报,35(8):2429-2434.
Hayes P K,Walsby A E,1984. An investigation into the recycling of gas vesicle protein derived from collapsed gas vesicles[J]. Journal of General Microbiology, 130:1591-1596.
Otero A, Vincenzini M, 2003. Extracellular polysaccharide synthesis by Nostoc strains as affected by N source and light intensity[J]. Journal of Biotechnology, 102(2):143-152.
Walsby A E,1988. Homeostasis in buoyancy regulation by planktonic cyanobacteria[M]. FEMS Symposium, 44: 99-116.
Zhang G M, Zhang P Y, Fan M H, et al, 2009. Ultrasound-enhanced coagulation for Microcystis aeruginosa removal[J]. Ultrasonics Sonochemistry, 16(3):334-338.