A framework for deriving dispatching rules of integrated urban drainage systems.

Area of Science:

• Environmental Engineering
• Water Resource Management
• Urban Planning

Background:

• Urban drainage systems (UDS) face challenges in sewage dispatch due to complex networks, data uncertainty, and multiple objectives.
• Integrating green and gray infrastructure in UDS is a growing trend, increasing dispatch complexity.

Purpose of the Study:

• To develop a novel framework for deriving UDS dispatching rules to allocate wastewater inflow based on treatment capacity.
• To address sewage volume uncertainty caused by rainfall and optimize operating costs and surface water quality.

Main Methods:

• Utilized the Prophet algorithm to forecast and manage sewage volume uncertainty from rainfall.
• Constructed a multi-objective optimization model for operating costs and surface water quality.
• Employed a decision tree for mining dispatching rules and identifying critical thresholds.

Main Results:

• Identified a critical sewage volume threshold (18.0 × 10⁵ m³ in winter) exceeding which surface water quality limits are breached.
• Demonstrated a competitive relationship between wastewater allocation, receiving water quality, and operating costs.
• Developed dispatching rules that effectively address scientific and reasonable UDS management.

Conclusions:

• The proposed framework provides a scientific basis for UDS sewage dispatch, improving efficiency and environmental outcomes.
• The decision tree approach successfully identifies risk thresholds for surface water quality.
• The study highlights the trade-offs between operational costs and water quality in wastewater management.