预氧化对混凝-气浮工艺去除铜绿微囊藻效果的影响

研究了预氧化(高锰酸钾、氯、过氧化氢)对混凝-溶气气浮工艺去除铜绿微囊藻的影响.通过检测出水浊度、藻类浓度以及UV254等指标来评价预氧化对藻类的去除效果.试验结果表明:在氧化剂最佳投量下,经过KMnO4、Cl2和H2O2预氧化后,藻类去除率分别提高了10.81%、11.65%以及9%,其中以氯对藻类去除效果最好,但预氯化过程中引起了藻细胞的破裂使得胞内有机物释放到水中,造成出水中UV254的升高.几种氧化剂对比研究结果表明,采用高锰酸钾预氧化不仅能够节约经济费用,而且不会因藻体内有机物的大量外流而降低出水水质的安全性.     

Limnological features of Funil Reservoir (R.J., Brazil) and indicator properties of rotifers and cladocerans of the zooplankton community

Funil Reservoir receives inflow from a highly industrialized region and acts as a natural sink to pollutants. Among the consequences of the uncontrolled nutrient loading is the constant presence and periodic heavy blooms of Microcystis aeruginosa . This study verified limnological features and zooplankton assemblage of the Funil Reservoir focusing on the environmental-indicator properties of rotifers and cladocerans. The summer bloom of M. aeruginosa caused reductions in water transparency, nitrate and orthophosphate concentrations and raises in chlorophyll a , pH, dissolved oxygen and chemical oxygen demand values. All zooplankton species presented spatial and temporal variations with the exception of the copepods, which were present in all samples. According to canonical correspondence analysis, ammonium was the variable most related to zooplankton variability and different Rotifera and Cladocera assemblages indicated distinct environment conditions. Rotifer taxa associated with increases of water temperature and chlorophyll a concentration were found with high densities during M. aeruginosa blooms. Species of rotifer and cladocerans are suggested as indicators that can be used to identify different physical and chemical gradients or eutrophic increases in Funil Reservoir.     

Mitigating cyanobacterial blooms: how effective are ‘effective microorganisms’?

This study examined the effects of ‘Effective Microorganisms (EM)’ on the growth of cyanobacteria, and their ability to terminate cyanobacterial blooms. The EM was tested in the form of ‘mudballs’ or ‘Bokashi‐balls’, and as a suspension (EM‐A) in laboratory experiments. No growth inhibition was observed for a laboratory strain of Microcystis aeruginosa and for M. aeruginosa from the field at the recommended dosage of 1 EM‐mudball per square‐metre (≈0.1–0.3 g L^?1). Cyanobacteria were inhibited only at very high concentrations (5–10 g L^?1 cyanobacteria), and a bloom was reduced, being attributed to the high amount of clay and high water turbidity. For these high dosage treatments, the dissolved oxygen concentration dropped initially to very low levels, with longer incubation indicating that nutrients were released from the material. The EM‐A suspension appeared ineffective in hampering cyanobacterial growths at recommended usage concentrations. EM‐mudballs released phosphate (160 μg P g^?1) and metals (aluminium, copper, traces of lead and lanthanum). The results of this study did not support the hypothesis that EM are effective in preventing cyanobacterial proliferation or in terminating blooms, thereby suggesting lake restoration by ‘Effective Microorganisms’ is not a convincing eutrophication control option.     

Algicidal effect of bacterial isolates of Pedobacter sp. against cyanobacterium Microcystis aeruginosa

The aim of this study was to isolate algicidal bacteria so as to control harmful cyanobacterium Microcystis aeruginosa (M.aeruginosa) blooms using biological methods. Nine bacterial strains were isolated to inhibit the growth of M. aeruginosa, among which the MaI11-5 bacterial strain exhibited remarkable algicidal activity against M. aeruginosa cells during the test. Based on the 16S rDNA analysis, the isolated MaI11-5 was identified as Pedobacter sp. through morphology and homology research. The results of cocultivation of the cyanobacteria with MaI11-5 algicidal isolates showed obvious algicidal activity against cyanobacterial cells. The algicidal effect of MaI11-5 exceeded 50% after two days, exceeded 70% after four days, and reached 80% after seven days. The observation results with a scanning electron microscope showed that the cyanobacterial cells aggregated and produced mucous-like substances when cocultivated with the algicidal bacteria. The results indicated that the MaI11-5 bacterial strain may possess a novel function for controlling harmful blooms and further studies will provide new insights into its role in water environment.     

不同密度铜锈环棱螺对沉水植物生长和水质的影响EI北大核心CSCD

通过试验研究不同密度铜锈环棱螺(Bellamya aeruginosa)对苦草(Vallisneria natans)和金鱼藻(Ceratophyllum demersum)生长及水质的影响。试验结果表明:铜锈环棱螺的存在显著促进了沉水植物的生长,高密度组苦草和金鱼藻的相对生长率分别是对照组的2.16和1.66倍,高密度组苦草和金鱼藻的相对伸长率分别是对照组的1.18和1.25倍;铜锈环棱螺的存在对水质有一定负面影响,水体电导率随着螺密度的增加而升高,溶解氧浓度随着螺密度的增加而降低,pH值、氧化还原电位和叶绿素浓度随着螺密度的增加没有一致的规律;水体氮的去除率随螺密度的增加呈下降趋势,高密度组苦草和金鱼藻对氮的去除率相对于对照组分别下降了70.0%和64.5%,磷的去除率组间没有显著差异;铜锈环棱螺密度对水体氮浓度变化起主要作用,方差占比为64%,沉水植物不同物种对水体磷浓度变化起主要作用,方差占比为72.54%。     

铜绿微囊藻的混凝特性与影响因素研究

以实验室纯培养的铜绿微囊藻为试验材料,用烧杯试验调查铜绿微囊藻的混凝特性。结果显示聚氯化铝(PAC)混凝铜绿微囊藻的效果较好。PAC对水样中铜绿微囊藻的混凝效果与藻的生长期、藻细胞胞外分泌物、温度、pH等有密切关系:铜绿微囊藻处于稳定期以及中性到弱碱性的pH范围有利于PAC混凝;温度对PAC混凝的影响与生长期有关,24-26℃对稳定期藻类的混凝沉淀最有利,对数期和衰亡期藻类需要较高的混凝温度(28-30℃);各个生长期铜绿微囊藻的胞外分泌物均有助于PAC的混凝沉降。天然水体中这些因素的耦合作用使得混凝工艺单元有效控制藻类变得困难。控制某一个或几个因素可以改善铜绿微囊藻混凝效果,其中以调节进水pH最为方便。     

再生水回用中氮磷对两种典型水华藻类生长影响研究

根据相关标准,试验选取了不同的氮磷浓度值,对蓝藻水华常见的铜绿微囊藻和绿藻水华常见的小球藻分别进行了单独培养以及两者的竞争试验.结果表明,铜绿微囊藻生长的最适氮磷浓度分别为15 mg/L、0.3～0.5 mg/L,小球藻生长的最适氮磷浓度分别为15 mg/L、0.1～0.5 mg/L;在氮磷比为15、30、50、150的试验条件下,竞争试验中的优势藻均为小球藻.建议以再生水为补水水源的景观水体中,再生水的氮磷浓度分别控制为:总氮≥15 mg/L、磷≤0.1 mg/L、氮磷比为150以上,能有效地抑制铜绿微囊藻生长.     

矿泉水中铜绿假单胞菌能力验证结果分析与讨论

目的：通过参加能力验证来提高实验室微生物检测能力,考核技术人员工作水平,提高实验室检测水平,增强实验室综合竞争力。方法：依据《食品安全国家标准饮用天然矿泉水检验方法》(GB 8538—2016)中铜绿假单胞菌的微生物检验方法,结合《矿泉水中铜绿假单胞菌的检测能力验证参试指导书》[ACAS-PT 1117(2021)]进行操作。结果：样品21-M873的鉴定结果为铜绿假单胞菌阳性,计数结果为8.7×103 CFU/250 mL;样品21-Q877的鉴定结果为铜绿假单胞菌阳性,计数结果为3.8×10³ CFU/250 mL。结论：本次能力验证活动取得了满意的结果,达到了实验室内部质控、人员考核、水平验证的预期目的,为日常检测工作积累了宝贵的经验。     

壳聚糖-沸石复合体对铜绿微囊藻的去除效果

研究壳聚糖、沸石单独絮凝除藻以及壳聚糖沸石复合体对铜绿微囊藻去除效果。结果表明：单独使用壳聚糖,质量浓度在0.6～1.1 mg/L时,对铜绿微囊藻的去除率超过90％;单独使用沸石,沸石质量浓度小于500 mg/L时,对铜绿微囊藻的去除率低于40％。经壳聚糖包覆改性后,壳聚糖沸石复合体对铜绿微囊藻絮凝去除能力大幅提高。当壳聚糖质量浓度为0.5 mg/L,沸石质量浓度为6～14 mg/L时,壳聚糖沸石复合体对铜绿微囊藻的去除率达90％以上。壳聚糖沸石复合体适用的pH值范围在5～7之间。