一般廢棄物暨農林部門產生溫室氣體之探討—以桃園縣為例

Abstract

近年來全球暖化造成環境氣候的劇烈變遷，全球暖化極有可能來自於人類活動所排放的溫室氣體。一般廢棄物及農業部門所排放的溫室氣體總量雖遠不及能源、工業所排放，進行溫室氣體排放量的調查推估可建立排放基線資料外，更能由盤查結果得知減量方向與空間。森林是陸地上主要的碳匯，藉由盤查可瞭解森林的碳匯能力。 桃園縣是近年來發展迅速的城市，工商活動頻繁且仍有部分的農業活動，曾經發生垃圾大戰且境內掩埋場眾多，垃圾掩埋所排放的甲烷是造成暖化的來源之一。本研究以桃園縣為案例，藉由實際調查與資料蒐集等，透過盤查探討一般廢棄物、農林業活動的溫室氣體排放現況。 研究結果顯示，以掩埋處理每公噸垃圾所造成的溫室效應明顯大於焚化垃圾所造成，但考量時間尺度的話，每日每公噸垃圾之溫室氣體排放量，以焚化處理所造成的溫室效應比掩埋所造成的影響來得大，且垃圾處理每年人均溫室氣體排放量為0.16 公噸(2002∼2006 年)。農業部門之排放源依排放量多寡依序為農耕土壤排放氧化亞氮(施用化肥)、禽畜腸道發酵排放甲烷、種植水稻排放甲烷、禽畜排泄物處理排放甲烷與氧化亞氮、農業殘餘物燃燒排放甲烷與氧化亞氮。2000∼2006 年每年桃園縣土地使用與林業部門之二氧化碳吸收量約為42.4 萬公噸，平均每公頃森林面積可吸收10.03 公噸的二氧化碳，且林業部門所吸收的二氧化碳總量略大於廢棄物及農業活動所排放的溫室氣體，排放量與吸收量相互抵銷。 建議從垃圾源頭減廢做起，提高資源回收率；積極進行造林計畫，農耕土壤合理化施肥及改變水稻田耕作時的浸水習慣，並建議著手實測農林業本土的溫室氣體排放係數及更新統計資料。

Globe warming most possibly resulted from the emission of greenhousegas (GHG) of human activities. The GHG emission from domestic waste and agriculture activities was much less than from energy and industrial, the inventory of GHG emission could establish the emission baseline and suggest which we can reduce the GHG emission. Forest is the important carbon sink, the inventory can show how much carbon absorbed by forest. Taoyuan is a rapidly growing city. It was with big trouble in domestic waste in the 1990s. This research takes the domestic waste treatment, agriculture and forest activities in Taoyuan as a case with real data to inventory the GHG emission and absorption in Taoyuan. The result shows the GHG emission from per ton waste treated by landfills is large than by incinerator, but emission of per ton waste-per day is large in incinerator than in landfills. The average emission from waste is 0.16 ton Carbon dioxide equivalent (CDE) per year-per person in 2002-2006. The GHG emission of agriculture activity was mainly from agriculture soil (N2O,mostly from use of chemical fertilizer), enteric fermentation (CH4) and rice cultivation (GH4). The absorption of CO2 of land use and forest (LUAF) is 42.4 ton CDE per year in 2000-2006, and the average CO2 absorption is 10.03 ton CDE per hectare of forest land. The absorption of GHG from LUAF is roughly large the emission from waste and agriculture. There're good suggestions of reducing waste, recycling waste, forestation, rational fertilization, and changing flooding habits in paddy soils to reduce the GHG emission. And it's necessary to develop the local coefficients of GHG emission and absorption.