人工濕地生態系統功能與經濟效益評估---人工濕地對台灣整體及區域經濟之衝擊影響及其溫室氣體減量潛力評估(III)

Abstract

2009年12月環保署進行淡水河流域水質監測的結果顯示，忠孝大橋、新海 大橋及三峽大橋等三處水質測站所量測到的結果為嚴重污染；淡水河系其他中 下游河段之河川水質則呈中度污染。而鄰近這三個水質量測站的鄉鎮市也正是 台北縣內居住人口最稠密的地區。這也顯示了污水下水道系統接管普及率仍低 的台北縣臨河市鎮所排放之生活污水為淡水河之主要污染源。此外，環境保護 署(2008)的數據也顯示：2007年生活污水、事業廢水及農業廢水之生化需氧量 (Biochemical Oxygen Demand, BOD)排放量分別占我國廢污水BOD總排放量的 55.31%、22.46%及22.23%，生活污水已取代事業廢水成為河川水質污染的最大 來源。 本研究計畫之第一年(目前進行中)擬建構一涵蓋台北市及毗鄰之台北縣境 內重點衛星都市之台北大都會區區域可計算一般均衡(Computable General Equilibrium, CGE)模型，並與台北都會區以外其他縣市之區域CGE模型連結，以 呈現跨區域間因產品與服務貿易所形成的產業連結與互動。本研究並擬於台北 大都會區之區域CGE模型中建立一人工濕地部門，呈現目前已開始運轉的3處位 於大漢溪右岸的新海橋人工濕地(一期及二期)及打鳥埤人工濕地，以及台北縣規 劃新增人工濕地之營運及維護成本、單位污水處理成本、人工濕地除污效率的 提升，以及其溫室氣體排放量與吸附量(sequestration)。我們將以此模型評估分 析大台北都會區區域內運轉中及增建之人工濕地，相較於污水下水道系統，在 其生活廢污水處理成本以及廢污水處理系統建造成本上的節約(cost savings)對 於大台北都會區內各區域之各個生產、消費及政府部門、及其他區域經濟之影 響，以及人工濕地對大台北都會區之溫室氣體減量的貢獻。 本研究之第二年(2010年8月至2011年7月)承繼第一年之研究成果，擬擴編第 一年之台北大都會區區域投入產出資料庫成為全國各縣市之區域投入產出資料 庫(原台北大都會區之鄉鎮市劃分仍然保留)，並於擴編之大台北都會區區域可計 算一般均衡模型中加入工業廢水處理部門及污水下水道系統部門，比較污水下 水道系統及人工濕地之生活廢污水處理成本，並模擬按差別污水處理成本課徵 水污染防制費對於大台北都會區內各個生產、消費部門以及其區域經濟之影 響。同時，我們也將計算台北都會區內各縣市鄉鎮水污染之質損值(environmental degradation)及各區域之綠色國民所得(green GDP)，並評估區域經濟發展對於人 工濕地生物多樣性(biodiversity)之影響。

As the recent EPA monitoring result indicated, the Da-Han River section of the Dan-Sui River are severely polluted. Main source of pollution is the wastewater being discharged from the towns adjacent to this section of the river, in which sanitary sewer is not yet accessible to all households and communities. Currently we are building a multi-regional computable general equilibrium (CGE) model for the economies of the satellite cities or towns of the Taipei metropolis, in which inter-region linkage through commodity and service trade is considered. In the Taipei metropolis multi-regional CGE model, we will set up a sector of the constructed wetlands to present the currently operating sites of constructed wetlands in the Taipei County along the Da-Han River for domestic wastewater treatment, and also the planned constructed wetlands elsewhere in the Taipei County. Construction, operation and maintenance costs, unit treatment costs, treatment efficiency and its improvement, and the net emissions of greenhouse gases (CO2 and CH4) will be incorporated to describe the constructed wetlands sector. The model will be used to assess the effect of using the constructed wetlands, as opposed to the sanitary sewer, in the cost-savings for wastewater treatment, and its impact on all sectors within the region, as well as other regions linked through inter-regional trade. In the second year of the project (August 2010 to July 2011), we plan to expand the Taipei metropolis CGE model into one that covers both the Taipei metropolis and other counties of Taiwan. Also we will add into this expanded multi-region CGE model of the Taipei metropolis the industrial wastewater treatment sector and the sanitary sewer sector. We will compare the costs of wastewater treatment with the three options, and assess with the multi-regional CGE model the economy-wide and inter-regional impact of the differential water pollution levies (on industrial and agricultural sectors, and households). The green GDP, which takes environmental degradation into account, will be calculated together with the results from the model simulations. We will also evaluate the impact of regional economic development on biodiversity in the constructed wetlands.