School of Natural Sciences, College of Environmental Sciences and Engineering, Bangor University, Gwynedd, UK.
School of Natural Sciences, College of Environmental Sciences and Engineering, Bangor University, Gwynedd, UK.
J Environ Manage. 2021 Dec 15;300:113613. doi: 10.1016/j.jenvman.2021.113613. Epub 2021 Sep 21.
The collection, treatment and disposal of wastewater is estimated to consume more than 2% of the world's electrical energy, whilst some wastewater treatment plants (WWTPs) can account for over 20% of electrical consumption within municipalities. To investigate areas to improve wastewater treatment, international benchmarking on energy (electrical) intensity was conducted with the indicator kWh/m and a quality control of secondary treatment or better for ≥95% of treated volume. The core sample included 321 companies from 31 countries, however, to analyse regional differences, 11 countries from an external sample made up of various studies of WWTPs was also used in places. The sample displayed a weak-negative size effect with energy intensity, although Kruskal-Wallace analyses showed there was a significant difference between the size of groups (p-value of 0.015), suggesting that as companies get larger; they consume less electricity per cubic metre of wastewater treated. This relationship was not completely linear, as mid to large companies (10,001-100,000 customers) had the largest average consumption of 0.99 kWh/m. In the regional analysis, EU states had the largest average kWh/m with 1.18, which appeared a result of the higher wastewater effluent standards of the region. This was supported by Denmark being the second largest average consuming country (1.35 kWh/m), since it has some of strictest effluent standards in the world. Along with energy intensity, the associated greenhouse gas (GHG) emissions were calculated enabling the targeting of regions for improvement in response to climate change. Poland had the highest carbon footprint (0.91 kgCOe/m) arising from an energy intensity of 0.89 kWh/m; conversely, a clean electricity grid can affectively mitigate wastewater treatment inefficiencies, exemplified by Norway who emit just 0.013 kgCOe per cubic meter treated, despite consuming 0.60 kWh/m. Finally, limitations to available data and the analysis were highlighted from which, it is advised that influent vs. effluent and net energy, as opposed to gross, data be used in future analyses. The large international sample size, energy data with a quality control, GHG analysis, and specific benchmarking recommendations give this study a novelty which could be of use to water industry operators, benchmarking organisations, and regulators.
据估计，废水的收集、处理和处置消耗了超过全球 2%的电力，而一些废水处理厂（WWTP）的耗电量可能占城市电力消耗的 20%以上。为了研究改善废水处理的领域，对能源（电力）强度进行了国际基准测试，指标为千瓦时/立方米（kWh/m），并对二级处理或以上的处理量进行了质量控制，达标率为 95%以上。核心样本包括来自 31 个国家的 321 家公司，但为了分析区域差异，还使用了来自不同 WWTP 研究的外部样本中的 11 个国家的数据。该样本显示，能源强度呈弱负规模效应，尽管 Kruskal-Wallis 分析表明，组的规模之间存在显著差异（p 值为 0.015），这表明随着公司规模的扩大，每立方米处理的废水中消耗的电量就会减少。这种关系并不是完全线性的，因为中型到大型公司（10001-100000 个客户）的平均耗电量最大，为 0.99 kWh/m。在区域分析中，欧盟国家的平均 kWh/m 最大，为 1.18，这似乎是该地区更高的废水排放标准的结果。丹麦是第二个平均耗电量最大的国家（1.35 kWh/m），这一结果也支持了这一观点，因为丹麦拥有世界上最严格的废水排放标准之一。除了能源强度，还计算了相关的温室气体（GHG）排放，从而能够针对气候变化，确定需要改进的区域。波兰的碳足迹最高（0.91kgCOe/m），这是由于其能源强度为 0.89 kWh/m；相反，清洁的电网可以有效地减轻废水处理效率低下的问题，挪威就是一个很好的例子，尽管其耗电量为 0.60 kWh/m，但每立方米处理的排放量仅为 0.013kgCOe。最后，还强调了可用数据和分析的局限性，因此建议在未来的分析中使用进水与出水、净能与总能耗数据，而不是使用后者。该研究的新颖之处在于，其国际样本规模大，能源数据经过质量控制，进行了温室气体分析，并提出了具体的基准测试建议，这可能对水务行业运营商、基准测试组织和监管机构有用。
