Assessing relationships between onsite wastewater treatment system maintenance patterns and system-level variables
Assessing relationships between onsite wastewater treatment system maintenance patterns and system-level variables
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DOI：
10.1016/j.scitotenv.2023.161851
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发表时间：
2023-02-01
影响因子：
9.8
通讯作者：
Capps，Krista A.
中科院分区：
文献类型：
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作者：
Connelly，Kyle N.;Wenger，Seth J.;Capps，Krista A.
在全球范围内，数以百万计的家庭依赖于现场废水处理系统（OWTS），如化粪池系统，以安全地处理和处置废水。传统的地下OWTS对于许多土地所有者来说是一种常见且负担得起的选择，并且在适当的位置和维护下有效地去除废水中的病原体和营养物污染。然而，OWTS也可以在流域的非点源污染时，他们不能正常运作。为了更好地了解OWTS维护和故障的驱动因素，我们探讨了OWTS年龄，环境特征（土壤条件，地形湿度指数，距离流），并在雅典克拉克县，格鲁吉亚，美国OWTS维修和抽水记录之间的关系。维修记录表明，研究中的8826个OWTS中有7.8%在78年的时间内进行了维修，维修后的OWTS的中位年龄为65岁。抽水记录显示，12.2%的OWTS在38个月内抽水（年化率为5.7%）。我们使用的一套广泛可用的环境变量作为预测因子，可能不够精细，无法检测到这种规模的单个系统维护模式。然而，我们发现最老的OWTS（>50年）有最高的修复概率和表现出液压故障的迹象。值得注意的是，新的OWTS（2-10年）几乎与最旧的系统一样可能出现液压故障的迹象。这些发现表明，维修和更换工作应针对使用寿命即将结束或接近结束的旧系统，除了持续监测旧系统外，所有OWTS应在安装一年后进行检查。通过利用可能已经存在的数据，其他地区的从业者可以使用这种可重复的方法来估计OWTS的性能。我们的数据和方法将支持优先考虑废水基础设施投资和政策的努力。
Globally, millions of households rely on onsite wastewater treatment systems (OWTSs), such as septic systems, to safely treat and dispose of wastewater. Conventional subsurface OWTSs are a common and affordable option for many landowners, and effectively remove pathogenic and nutrient pollution from wastewater when properly sited and maintained. However, OWTSs can also be a source of nonpoint pollution in watersheds when they are not functioning properly. To better understand the drivers of OWTS maintenance and failure, we explored relationships between OWTS age, environmental characteristics (edaphic conditions, topographic wetness index, and distance to stream), and repair and pumping records for OWTSs in Athens-Clarke County, Georgia, USA. Repair records indicated that 7.8 % of the 8826 OWTSs in the study were repaired over a 78-year period and that the median age of a repaired OWTSs was 65 years old. Pumping records showed that 12.2 % of the OWTSs were pumped in a 38-month period (an annualized rate of 5.7 %). The suite of widely available environmental variables we used as predictors were likely not granular enough to detect patterns of individual system maintenance at this scale. However, we found that the oldest OWTSs (>50 years) had the highest probabilities of being repaired and exhibiting signs of hydraulic failure. Notably, new OWTSs (2–10 years) were nearly as likely as the oldest systems to exhibit signs of hydraulic failure. These findings suggest that repair and replacement efforts should target older systems that are at or near the end of their serviceable life, and, in addition to continually monitoring older systems, all OWTSs should be inspected one year after installation. By leveraging data that may already exist, practitioners in other localities can use this reproducible approach to estimate the performance of OWTSs. Our data and methods will support efforts to prioritize wastewater infrastructure investments and policies.