Environment and Public Health Research and Enterprise Group, Centre for Aquatic Environments, School of Environment and Technology, University of Brighton, Cockcroft Building, Lewes Road, Brighton BN2 4GJ, United Kingdom.
South East Water Ltd. Rocfort Road, Snodland, Kent, ME6 5AH, United Kingdom.
Sci Total Environ. 2020 Jun 20;722:137799. doi: 10.1016/j.scitotenv.2020.137799. Epub 2020 Mar 8.
Water deficit, exacerbated by global population increases and climate change, necessitates the investigation of alternative non-traditional water sources to augment existing supplies. Indirect potable reuse (IPR) represents a promising alternative water source in water-stressed regions. Of high concern is the presence of pathogenic microorganisms in wastewater, such as enteric viruses, protozoa and bacteria. Therefore, a greater understanding of the potential impact to human health is required. The aim of this research was to use a quantitative microbial risk assessment (QMRA) approach to calculate the probability of potential pathogen infection risk to the public in surface waters used for a range of recreational activities under scenarios: 1) existing de facto wastewater reuse conditions; 2) after augmentation with conventionally treated wastewater; and 3) after augmentation with reclaimed wastewater from proposed IPR schemes. Forty-four 31 l samples were collected from river sites and a coastal wastewater treatment works from July 2016-May 2017. Concentrations of faecal indicator organisms (enterococci, faecal coliforms, somatic coliphages and Bacteroides phages) determined using culture-based approaches and selected pathogens (adenovirus, Salmonella and Cryptosporidium) determined using molecular approaches (qPCR) were used to inform QMRA. The mean probability of infection from adenovirus under de facto conditions was high (>0.90) for all recreational activities, per single event. The risk of adenovirus and Cryptosporidium infection increased under augmentation scenario (2) (mean probability 0.95-1.00 and 0.01-0.06 per single event, respectively). Adenovirus and Cryptosporidium infection risk decreased under reclaimed water augmentation scenario (3) (mean probability <0.79, excluding swimming, which remained 1.00 and <0.01 per single event, respectively). Pathogen reduction after reclaimed water augmentation in surface waters impacted by de facto reuse, provides important evidence for alternative water supply option selection. As such, this evidence may inform water managers and the public of the potential benefits of IPR and improve acceptance of such practices in the future.
水短缺，加之全球人口增长和气候变化，促使人们研究替代性非传统水源，以补充现有水资源。间接饮用水再利用（IPR）是水资源紧张地区有前途的替代水源。人们高度关注废水中存在的致病微生物，如肠道病毒、原生动物和细菌。因此，需要更好地了解其对人类健康的潜在影响。本研究旨在采用定量微生物风险评估（QMRA）方法，计算在以下三种情况下，公众在用于各种娱乐活动的地表水中潜在病原体感染风险的概率：1）现有事实上的废水再利用条件；2）经传统处理的废水补充后；3）经拟议的 IPR 方案回收废水补充后。2016 年 7 月至 2017 年 5 月，从河流和沿海污水处理厂采集了 44 个 31 升样本。使用基于培养的方法测定粪便指示生物（肠球菌、粪便大肠菌群、体腔噬菌体和拟杆菌噬菌体）的浓度，并使用分子方法（qPCR）测定选定的病原体（腺病毒、沙门氏菌和隐孢子虫），用于 QMRA。在实际条件下，腺病毒的单次感染概率对于所有娱乐活动都很高（>0.90）。在补充方案 2（腺病毒和隐孢子虫感染的平均概率分别为 0.95-1.00 和 0.01-0.06）下，腺病毒和隐孢子虫感染的风险增加。在再生水补充方案 3（平均概率<0.79，游泳除外，仍为 1.00 和<0.01）下，腺病毒和隐孢子虫感染的风险降低。在受事实上再利用影响的地表水中，再生水的添加可减少病原体，为替代供水选择提供了重要证据。因此，该证据可以为水管理人员和公众提供 IPR 的潜在好处，并提高未来对这些实践的接受度。
