Walker Nathan L, Styles David, Gallagher John, Prysor Williams A
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; School of Engineering, University of Limerick, Limerick, Ireland.
J Environ Manage. 2021 Jun 1;287:112317. doi: 10.1016/j.jenvman.2021.112317. Epub 2021 Mar 11.
The provision of fundamental services by water and sewage companies (WaSCs) requires substantial energy and material inputs. A sustainability assessment of these companies requires a holistic evaluation of both performance and efficiency. The Hicks-Moorsteen productivity index was applied to 12 WaSCs in the United Kingdom (UK) over a 6-year period to benchmark their sustainability, based on eight approaches using different input and output variables for efficiency assessment. The choice of variables had a major influence on the ranking and perceived operational efficiency among WaSCs. Capital expenditure (utilised as part of total expenditure) for example, is an important input for tracking company operations however, potential associated efficiency benefits can lag investment, leading to apparent poor short-term performance following capital expenditure. Furthermore, water supplied and wastewater treated was deemed an unconstructive output from a sustainability perspective since it contradicts efforts to improve sustainability through reduced leakage and consumption per capita. Customer satisfaction and water quality measures are potential suitable alternatives. Despite these limitations, total expenditure and water supplied and wastewater treated were used alongside customer satisfaction and self-generated renewable energy for a holistic sustainability assessment within a small sample. They indicated the UK water sector has improved in productivity by 1.8% on average for 2014-18 and still had room for improvement, as a technical decline was evident for both the best and worst performers. Collectively the sample's production frontier was unchanged but on average companies moved 2.1% closer to it, and further decomposition of productivity revealed this was due to improvements in economies of scale and scope. Careful selection of appropriate input and output variables for efficiency benchmarking across water companies is critical to align with sustainability objectives and to target future investment and regulation within the water sector.
供水和污水处理公司（WaSCs）提供基本服务需要大量的能源和物质投入。对这些公司进行可持续性评估需要对其绩效和效率进行全面评估。在六年时间里，希克斯-穆尔斯廷生产率指数被应用于英国的12家供水和污水处理公司，以基于使用不同投入和产出变量进行效率评估的八种方法来衡量它们的可持续性。变量的选择对供水和污水处理公司的排名以及所感知的运营效率有重大影响。例如，资本支出（作为总支出的一部分使用）是跟踪公司运营的重要投入，然而，潜在的相关效率收益可能滞后于投资，导致资本支出后短期内表现明显不佳。此外，从可持续性角度来看，供应的水和处理的废水被视为非建设性产出，因为这与通过减少漏损和人均用水量来提高可持续性的努力相矛盾。客户满意度和水质指标是潜在的合适替代指标。尽管存在这些局限性，但在一个小样本中，总支出、供应的水和处理的废水与客户满意度和自产可再生能源一起被用于全面的可持续性评估。结果表明，2014 - 2018年英国水务部门的生产率平均提高了1.8%，仍有改进空间，因为表现最佳和最差的公司都明显出现了技术下滑。总体而言，样本的生产前沿没有变化，但各公司平均向其靠近了2.1%，生产率的进一步分解表明这是由于规模经济和范围经济的改善。为水务公司的效率基准精心选择合适的投入和产出变量，对于符合可持续性目标以及确定水务部门未来的投资和监管方向至关重要。
