基于层次分析法的污水管网风险评价模型研究

Research on risk evaluation model of sewage network based on hierarchical analysis method

城市污水管网承担着收集污水的职能,是城市的生命线之一。污水管网的健康状况直接关系到城市环境和人民生活质量,然而在长期的使用和环境影响下,其存在着多种风险。本文从管道特性、外部环境、管理制度、应急预案4个方面来构建了城市污水管网风险评价指标体系,共包含了12个指标;采用变异系数法对指标权重赋值,通过标准极差法将定性的指标转化为定量的指标,确定出得分在0.3以下的管网需要优先被修复;对选取的30个污水管网点位进行了风险评价,结果表明污水管网的风险因素是相互独立存在的。通过模型分析后组织了相应的工程和管理措施,优先修复风险高的管网,尽量采取整体修复及非开挖修复,通过一系列措施不仅节省人力物力资源,提高了管网维护的费效比,最终使得研究区域污水收集率提高,污水厂进水浓度显著提升。

The urban sewage pipe network takes on the function of collecting sewage,and is one of the lifelines in the city.The health condition of the sewage network is directly related to the urban environment and people’s quality of life.However,there are many risks under the long-term use and environmental impact.This paper constructs a risk evaluation index system of urban sewage pipe network from the following four aspects:pipe characteristics,external environment,management system,and emergency plan.The system contains 12 indexes,and adopts the coefficient of variation method to assign values to the indexes’weights,and the qualitative indexes are transformed to quantitative indexes through the standard extreme deviation method to determine that the pipe networks with scores below 0.3 need to be repaired as a matter of priority.The risk evaluation on 30 selected sewage pipe network locations is conducted,the results showed that the risk factors of the sewage network exist independently of each other.After the model analysis,corresponding engineering and management measures were organized to prioritize the repair of high-risk pipe networks by using overall repair and non-excavation repair as much as possible.The measures not only save human and material resources,but also improve the cost-effectiveness ratio of the pipe network maintenance,which ultimately improves the sewage collection rate in the study area and increases the concentration of sewage intake water in wastewater treatment plants significantly.