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Investigating the coagulation of non-proteinaceous algal organic matter: Optimizing coagulation performance and identification of removal mechanisms

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Journal of Environmental Sciences 2019年第5期31卷 25-34页

作者： Jana Naceradska Katerina Novotna lenka cermakova Tomas Cajthaml Martin Pivokonsky Institute of Hydrodynamics of the Czech Academy of Sciences Institute of Microbiology of the Czech Academy of Sciences

The removal of algal organic matter(AOM) is a growing concern for the water treatment industry worldwide. The current study investigates coagulation of non-proteinaceous AOM(AOM after protein separation), which has been minimally explored compared with proteinaceous fractions. Jar tests with either aluminum sulphate(alum) or polyaluminium chloride(PACl) were performed at doses of 0.2–3.0 mg Al per 1 mg of dissolved organic carbon in the p H range 3.0–10.5. Additionally, non-proteinaceous matter was characterized in terms of charge, molecular weight and carbohydrate content to assess the treatability of its different fractions. Results showed that only up to 25% of non-proteinaceous AOM can be removed by coagulation under optimized conditions. The optimal coagulation p H(6.6–8.0 for alum and 7.5–9.0 for PACl) and low surface charge of the removed fraction indicated that the prevailing coagulation mechanism was adsorption of non-proteinaceous matter onto aluminum hydroxide precipitates. The lowest residual Al concentrations were achieved in very narrow p H ranges, especially in the case of PACl. High-molecular weight saccharidelike organics were amenable to coagulation compared to low-molecular weight(< 3 k Da)substances. Their high content in non-proteinaceous matter(about 67%) was the reason for its low removal. Comparison with our previous studies implies that proteinaceous and nonproteinaceous matter is coagulated under different conditions due to the employment of diverse coagulation mechanisms. The study suggests that further research should focus on the removal of low-molecular weight AOM, reluctant to coagulate, with other treatment processes to minimize its detrimental effect on water safety.

关键词： Algal organic matter Chlorella vulgaris Coagulation Flocculation Non-proteinaceous matter Water treatment

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Influence of COM-peptides/proteins on the properties of flocs formed at different shear rates

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Journal of Environmental Sciences 2019年第6期31卷 116-127页

作者： Monika Filipenska Petra Vasatova lenka Pivokonska lenka cermakova andrea Gonzalez-Torres Rita K.Henderson Jana Naceradska Martin Pivokonsky Institute of Hydrodynamics of the Czech Academy of Sciences Institute for Environmental Studies Faculty of Science Charles University The bioMASS Lab School of Chemical Engineering The University of New South Wales

Coagulation followed by floc separation is a key process for the removal of algal organic matter(AOM) in water treatment. Besides optimizing coagulation parameters,knowledge of the properties of AOM-flocs is essential to maximizing AOM ***, the impact of AOM on the floc properties remains unclear. This study investigated how peptides/proteins derived from the cellular organic matter(COM) of the cyanobacterium Microcystis aeruginosa influenced the size, structure, and shape of flocs formed at different shear rates(G). Flocs formed by kaolinite, COM-peptides/proteins and a mixture of the same were studied, and the effect of intermolecular interactions between floc components on floc properties was assessed. The coagulation experiments were performed in a Taylor–Couette reactor, with aluminum(Al) or ferric sulphate(Fe) utilized as coagulants. Image analysis was performed to gauge floc size and obtain data on fractal dimension. It was found that floc properties were affected by the presence of the COM-peptides/proteins and the coagulant used. COM-peptides/proteins increased floc size and porosity and widened floc size distributions. The Fe coagulant produced larger and less compact flocs than Al coagulant. Moreover, the decrease in floc size that occurred in parallel with increase in shear rate was not smooth in progress. A rapid change for the kaolinite-coagulant suspension and two rapid changes for the suspensions containing COM were observed. These were attributed to various intermolecular interactions between floc components participating in coagulation at different G. Based on the results obtained, shear rates suitable for efficient separation of flocs containing COM were suggested.

关键词： Algal organic matter Floc size Coagulation Image analysis Water treatment

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Only mothers feed mature offspring in European Ceratina bees

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Insect Science 2021年第5期28卷 1468-1481页

作者： Michael Mikat Jitka Waldhauserova Tereza Frankova Katerina cermakova Vojtech Broz Simon Zeman Marcela Dokulilova Jakub Straka Department of Zoology Faculty of ScienceCharles UniversityPragueCzech Republic Jihlava Grammar School JihlavaCzech Republic Department of Ecology Faculty of ScienceCharles UniversityPragueCzech Republic

Parental care directed to adult offspring is uncommon in *** parental care has been documented in Xylocopinae bees(Hymenoptera:Apidae).Moreover,some Ceratina bees(Xylocopinae)are known to feed mature siblings,and feeding of mature siblings is achieved by dwarf eldest daughters when mothers *** daughters are intentionally malnourished by mothers and usually originate from the first brood ***,we examined the pattern of care prov ided to young adults in three small European carpenter bees:Ceratina(Ceratina)cucurbitina,C.(Euceratina)chalybea,and C.(E.)*** of nest departures and arrivals were performed to study foraging *** detected intensive foraging behavior of mothers in all three studied ***,we did not observe regular foraging bchavior of daughters in any *** experimental removal of mothers in *** led to the emigration of young adults and did not initiate foraging activity in *** conclude that the feeding of siblings does not occur in these species unlike in the American species *** detected female-biased sex ratios in the first brood cell in *** and *** offspring in the first brood cell was smaller than other female offspring only in *** results show that a female-biased sex ratio and the small size of daughters in the first brood cell do not provide sufficient ev idence for demonstrating the existence of an altruistic daughter and also that the pattern of maternal investment is not exclusively shaped by social interactions.

关键词： foraging trip Hymenoptera maternal care provisioning sociality Xylocopinae

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奶牛缩短干奶期管理与常规管理的比较

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饲料博览 2014年第10期24卷 50-50页

作者： cermakova J Kudrna V Simeckova M Vyborna A Dolezal P Illek J

研究旨在比较两种干奶期奶牛管理,评估缩短干奶期饲养管理对奶牛采食量、代谢和泌乳早期产后性能的影响。29头奶牛随机分为2组。对照组(CON组,n=14)奶牛采用传统饲养管理(约60 d,57±5.9 d),饲喂干奶早期奶牛直到其预期分娩。从分娩前21... 详细信息

研究旨在比较两种干奶期奶牛管理,评估缩短干奶期饲养管理对奶牛采食量、代谢和泌乳早期产后性能的影响。29头奶牛随机分为2组。对照组(CON组,n=14)奶牛采用传统饲养管理(约60 d,57±5.9 d),饲喂干奶早期奶牛直到其预期分娩。从分娩前21d到预期分娩,奶牛饲料更换为添加3 kg浓缩料的预产犊料。试验组(SDP组,n=15)奶牛采用缩短干奶期饲养管理(35±6.3 d),从产前60 d至分娩连续饲喂后期哺乳饲粮。产犊后,两组奶牛饲喂相同哺乳饲粮。与饲喂60 d的对照组相比,试验组奶牛的干物质采食量约为4.11 kg·头-1·d-1,高于对照组,然而对产后干物质采食量无显著影响。试验组奶牛在产后100 d内所产牛奶较对照组减少2.78 kg·d-1,但在统计学上无显著差异。两组奶牛体重、体况评分和脂肪厚度均无显著差异。同样,两组奶牛的血浆代谢物质的浓度也无显著差异。试验组奶牛在分娩前,其pH较对照组降低,乳酸和挥发性脂肪酸的浓度较对照组增高。在产后,两组奶牛的乳酸、挥发性脂肪酸、NH3和瘤胃液pH均无显著差异。缩短干奶期饲养对犊牛初生重和初乳质量无显著影响。研究结果提示,综合考虑奶牛干物质采食量和产奶量,传统的奶牛干奶期饲养管理与采用哺乳饲粮饲喂整个干奶期奶牛来缩短干奶期时间的饲养管理相比,前者更有利。

关键词：营养过渡期牛奶产量代谢状态

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