The potential to restore eutrophic freshwater systems in the UK with economic benefits

对全球淡水系统的最大威胁是污染，考虑到世界人口预计将在不到30年的时间内达到90亿，这些问题可能会恶化。最初，主要的输家似乎是野生动物、游客和工业。然而，随着对清洁饮用水的需求随着人口规模的增加而增加，这一问题将进一步扩大。全球空间时间序列分析已经将战争与淡水供应联系起来（1）。主要原因是过去50年来营养水平大幅提高，这要归功于生活垃圾的排放以及农业实践和城市发展造成的污染。藻类大量繁殖是由于营养物质（氮和磷）增加而发生的，这随后导致需要氧气的细菌增加，从而对生态系统造成进一步的有害影响，包括鱼类死亡（称为富营养化）。通常被认为是发展中国家的一个问题，现在已知超过75%的英格兰地表淡水被归类为富营养化（2），管理成本从每年7500万英镑到1.14亿英镑不等（3）。控制富营养化的努力包括生物操纵，例如添加捕食性鱼类以改变食物网结构并增加“食藻动物”的存在。此外，还努力限制养分输入。这两种方法都取得了有限的成功。通过收获去除藻类可能会产生更直接的影响，可以作为一种独立的补救工具或与上述方法结合使用。然而，收获是一个能源密集型的过程，直到现在。谢菲尔德大学发明的获奖设备已被证明在收获藻类方面的效率超过99%，并且与竞争技术相比需要很少的能量输入（4，5）。称为微浮选，它依赖于产生微小的，非聚结的，均匀的微泡。这种去除污染藻类的方法将被应用于加速修复已经形成藻类水华的淡水系统。回收的藻类生物质可以作为一种资源用于各种应用，这与这种修复方法呈现出“隐藏”的经济效益。藻类是高度多样化的，单细胞或多细胞生物体，主要由脂质，蛋白质和碳水化合物组成。油脂含量可以高达80%，这些可以很容易地转化为生物柴油，这种燃料可以很容易地融入我们目前的能源使用基础设施。虽然蓝藻（蓝绿藻）的脂质含量较低（15-20%），但它们也可以转化为生物柴油。这里的燃料生产可以用来抵消收获和补救的成本。藻类也是一种丰富的蛋白质来源，可用于动物或鱼类饲料。营养成分（P和N）意味着回收的藻类也可以用作肥料，同时，由于几代人的种植使用，农业土壤已经恶化。总之，从污染环境中回收的藻类有许多令人兴奋的用途。尽管我们的水系统中存在大量关于藻类的数据，但这些数字尚未被整理和翻译以量化所描述的概念。该催化剂赠款旨在分析这些数据。它还旨在组建一个多技能团队，研究对自然环境、土地所有者、农民、公众、湖泊保护团体和游客的影响。它还旨在从生物燃料工艺工程师那里汲取专业知识。从废物中回收资源的概念代表了系统设计的生态工程方法，这些概念将用于吸引当地学校的学生，扩大研究的影响并激励下一代工程师和科学家。例如，2005年6月21-23日。2. JNCC报告，2001年。3. Pretty，J.N.，例如，2003，37，201-208.4.Hanotu，J.，例如，2011.5.Zimmerman，W. B.，例如，2011，16，350-356.

The biggest threat to global freshwater systems is pollution, and considering the World's population is expected to top 9 billion in less than 30 years (1), the problems are likely to worsen. Initially, the major losers appear to be wildlife, tourists and industry. However, the problem will extend much further as the demand for clean drinking water increases with population size. Global spatial time-series analyses have already linked wars to freshwater availability (1). The main cause is hugely increased nutrient levels over the last 50 years, thanks to discharges of domestic waste and pollution from agricultural practices and urban development. Algal blooms occur due to increased nutrients (nitrogen, N and phosphorus, P), which subsequently lead to increases in oxygen demanding bacteria that resulting in further detrimental effects to the ecosystem, including fish kills (termed eutrophication). Often perceived as a problem for developing countries, it is now known that over 75% of England's surface freshwater is classified as eutrophic (2) and the costs for managment extend from £75-114m per year (3).Efforts to control eutrophication include biomanipulation, e.g. adding predatory fish to alter food web structure and increase presence of 'algae-eaters'. There have also been efforts to limit nutrient input. Both methods have had limited success. Removing the algae by harvesting would potentially produce a more immediate impact and could be used as a stand-alone remediation tool or combined with the aforementioned methods. However, harvesting was an energy intensive process, until now. An award-winning device invented at the University of Sheffield has been shown to be over 99% efficient at harvesting algae and requires very little energy input compared to competitive technologies (4,5). Termed microflotation, it relies on the creation of tiny, non-coalescing, uniform microbubbles. This method of removing the polluting algae would be applied to accelerate remediation of freshwater systems where algal blooms have formed. The recovered algae biomass can then be used as a resource for a variety of applications and this presents the 'hidden' economic benefits with this remediation method.Algae are highly diverse, single- or multi-cellular organisms comprised of mostly lipids, protein, and carbohydrates. Lipid content can each up to 80% and these can be readily converted into bio-diesel, a fuel type that can easily integrate into our current energy-use infrastructure. Although cyanobacteria (blue-green algae) have lower lipid levels (15-20%), these too can be converted to biodiesel. The production of fuel here can be used to offset the costs of harvesting and remediation. Algae are also a rich source of protein which can be used for animal or fish feed. The nutrient content (P and N) means recovered algae can also be used a fertiliser and at the same time, condition agricultural soil which has deteriorated due to generations of cultivation use. In summary, there are arrays of exciting uses for recovered algae from polluting environments. And although tremendous amounts of data on algae in our water systems exist, the numbers have not been collated and translated to quantify the concepts described. This catalyst grant aims to analyse this data. It also aims to assemble a multi-skilled team to look at the impact on the natural environment, landowners, farmers, the public, lake protection groups and tourists. It also aims to draw in expertise from biofuel process engineers. The notion of recovering resources from waste represents an ecological engineering approach to system design, and these concepts will be used to engage students in a local school, widening impact of the research and inspiring next generation engineers and scientists.1.Levy, M., et al., June 21-23, 2005.2.JNCC Report, 2001.3.Pretty, J. N., et al., 2003, 37, 201-208.4.Hanotu, J., et al., 2011.5.Zimmerman, W. B., et al., 2011, 16, 350-356.