工業區污水下水道管渠負荷改善分析

Abstract

工業區污水下水道管渠系統隨著工業區之發展及污水量的增加，以及管線老舊效能降低，使得管線系統的容量負荷增加而過載，甚至造成溢流的環境污染。此溢流問題通常利用紓流管路(relief sewers)將過載或溢流的污水送至流量負荷較輕的管渠，或以更換管線的方式增加原下水道之容量，來解決流量過載或溢流的問題；而此二種方案分析時，均須考慮到管路中管線的流量、流速、及水深等狀況，本研究採用EPA Storm Water Management Model(SWMM)中EXTRAN BLOCK數學模式協助分析這些方案，而在選擇適當方案時，還須要考量整體污水下水道管渠的配置，將管線的空間做最佳的利用，本研究針對上述問題發展一個程序來產生一些可行的配置方案，並比較成本來選擇較佳的配置方案，以解決負荷過載的問題。 本研究以新竹科學工業園區污水下水道為案例，首先以SWMM-EXTRAN進行水理的模擬及驗證，然後針對管線流量過載及人孔溢流之區域，以增加紓流管路或更換原下水道管路等方式，以管線的容量為解決現階段溢流或過載的重點，在流速、坡度、管徑滿足一般下水道管渠設計的原則下，設計一些配置方案，配合SWMM-EXTRAN以求得可行的配置方案；並進一步以成本函數估算各可行性配置方案之概略成本，並分析各可行的優劣，以求得最適之配置改善污水下水道管渠之超負荷現象。 根據結果，紓流管路可產生的配置方案較更換管路的為多樣性，但相對在成本方面較更換管路為高，而利用這二種程序所產生的配置方案均能有效的改善工業區污水下水道管渠負荷過載的問題。

The rapid development of an industrial district may significantly increases the amount of wastewater generated within the district and therefore exceeds the transport capability originally designed of its sewer network. Excessive overload, or called surcharge, of a sewer network can cause serious flooding problems during the peak season. Two alternatives are usually employed to resolve this surcharge problem: (1) placing relief sewer pipes to divert flow from overloaded pipes into other downstream pipes that can accept the diverted flow; and (2) replacing overloaded pipes by larger ones. Various factors including flow rate, velocity, depth, and capacity of the sewer network should be carefully evaluated before a good alternative can be selected. This study proposed a systematic design procedure to facilitate this analysis for obtaining appropriate alternatives to resolve a surcharge problem. The EXTRAN module of the SWMM model is used to simulate the flow pattern in a sewer network. A case study for the west portion of the sewer network in the Hsinchu Science-based Industrial Park is implemented. Feasible layouts for resolving the surcharge problem are generated by the proposed procedure. Appropriate alternatives are selected primarily based a cost function. The results show that layouts with pipe replacements are more cost effective than those with relief pipes. However, both relief and replacement approaches can effectively resolve the surcharge problem of the studied area.