4-1 Materials Balances and Waste Audits
4-2
Hazardous Waste Site Assessments
4-3
Estimation of Source Concentrations for Hazardous Material Spills
4-4
Source Sampling
4-5
Source Sampling Procedures and Strategies
4-6
Sampling Away from the Source
4-7
Priority Pollutant and Sampling Analyses
4-8
Summary of Important Points and Concepts
In Chapter 4, procedure for describing,
assessing, and sampling hazardous wastes industrial facilities and contaminated
sites are presented. Specific procedures addressed include waste audits,
fundamentals in the assessment of contaminated sites, estimation of mass
concentrations of spills, sampling fundamentals, and chemical analysis.
4-1 Materials Balances and Waste Audits (查核)
l
Hazardous wastes must be organized, stored, and disposed of in a safe and efficient manner. (Fig. 4.1)
l The tracking of
hazardous wastes within an industry, a waste transfer station, or after
excavation from a contaminated site is called a hazardous waste audit.
l
The first step for an industry in assessing, organizing, tracking,
and minimizing hazardous wastes is to quantify all of the source materials that
it receives (input) and balance these with the waste leaving the facility,
which usually take place through waste disposal routes.
l The basis for a
hazardous waste audit is a source material balance. (Fig. 4.2)
l One of the goals of pollution prevention
programs (污染預防計畫) is the
optimization of process conditions to improve yields of the products while
decreasing the volume of side streams that contain unreacted materials and
waste products.
l The primary routes by
which unreactive waste leave an industrial facility are:
(1) Industrial wastewater
discharges,
(2) Waste management
activities,
(3) Volatilization,
(4) Spillage and other
unaccounted losses.
4-2
Hazardous Waste Site Assessments (現地評估)
l
Abandoned landfills, surface impoundments, and other hazardous
waste sites must be assessed to determine the extent of contamination before
cleanup is initiated.
l
Site assessments follow a common procedure that is divided into three phases.
Phase I assessment: preliminary assessment, initial assessment study, to confirm the
suspicious of the presence of hazardous waste. It involve paper research
including a chemical inventory evaluation, interview with current and former
personnel and neighbors, and regulatory agency record searches and interviews,
search of historical documents including newspaper reports of spills and
official records.
Phase II study: warranted to
confirm or deny the presence of hazardous wastes in the site. A detailed
evaluation of pathways and potential receptors is begun, which may include an
analysis of the subsurface by a hydrogeologist to assess groundwater flow
directions and travel times to drinking water wells or other receptors.
Phase III studies: to detail the
extent of contamination in terms of the area, volume, and contaminant
concentrations. Depending on the source characteristics, age of the site, and
predominant pathways, the source and adjacent areas may be sampled extensively.
4-3
Estimation of Source Concentrations for Hazardous Material Spills
l
Emergency response assessment (緊急應變評估): to estimating (1) the
mass of the material spilled and (2) the mass of the soil or solid onto which
the chemical has been spilled in order to compute a mass/mass concentration.
(example 4.2)
4-4
Source Sampling
l Statistical
Fundamentals for Sampling
l Sampling Procedures
（一）採樣樣品數：採樣樣品數須要依據採樣目的、廢棄物儲存容器體積數量、或是預估總容量及背景資料、特性分析等加以推估。
1、一般事業單位產生之桶裝廢棄物，先將採樣範圍內每一容器加以編號，參考表一廢棄物總量大小與最少採樣樣品數關係表，決定採樣數後，依隨機採樣方式由表二亂數表挑選擬採處。如廢棄物為正常均勻分佈時，可逕採集3至5個樣品。
2、廢棄物場址之採樣可先預估大概體積，依上述方式參考表一決定採樣數。合理的採樣樣品數可用試誤法（try and error method）確定，程序如下：
（1）分析每一個樣品，得各測定值 X1, X2, X3, …。
（2）計算樣品之平均值（sample mean）、變異數（variance of sample）S2。
（3）由樣品數n，查司徒頓Student ”t.20”值表（表三）。
（4）計算信賴區間（Confidence interval簡稱CI）。
（5）由信賴區間（CI）與管制值（RT）或常規值比較，是否超過管制值或常規值。
（6）如信賴區間上下限小於管制值或常規值，可定義為未超過管制值或常規值，就不用再繼續採樣，否則定義為超出管制值或常規值。亦可利用程序（1）之數值重新計算採樣數 n1（可預先多採數個樣品以作為 n2 - n1 之備份樣本），採樣分析、計算，作進一步的評估。
樣品平均值=
/ n n = 測定樣品數
樣品變異數S2 =-
/n
/ n-1
樣品標準偏差
標準誤差
管制值RT或常規值 = 依廢棄物管制法規不同項目而異
採樣約略數 n = (t.202 *.S2 ) / ( RT -
信賴區間CI =
自由度df = n - 1
l Stratified Random
Sampling
4-5
Source Sampling Procedures and Strategies
4-5.1
Sampling Devices (Fig. 4.6)
l Tanks and Drums:
Coliwasa, Weighted Bottle, Dipper, Thief.
1、液態樣品
（1）採樣瓶（Bottle sampler）：由金屬支撐架固定採樣瓶。亦可將玻璃瓶以清潔繩索綁妥再增掛一重錘。
（2）採樣杓（Dipper sampler）：由合成樹脂、鋁或不銹鋼材質製之可伸縮調整長柄，結合一玻璃或塑膠杯。
（3）綜合式廢液採樣管（Coliwasa）：由直徑約1-2英吋、長度約150cm之塑膠或玻璃管製，管下端附矽膠、鐵氟龍或橡膠材質之底塞，底塞由不銹鋼條連接以便操控。亦可使用可棄式適當口徑（約1cm以大拇指封閉者），長約120 cm之玻璃管。
（4）採樣泵（Pump）：使用蠕動式、離心式或其他型式泵。依樣品情況不同選擇合適者。
除可棄式採樣器材外，使用後應先以毛或鋼刷（鋼刷只能使用於不銹鋼材質採樣器材）刷洗附著物，再以清潔劑、自來水洗滌數次，最後以蒸餾水淋洗晾乾。
l Soil and Sludge: Hand
augers,
2、固態樣品
（1） 採樣刀（Trier sampler）：具有握柄或直管式不銹鋼材質製（如圖例五、六）。
（2） 套管式採樣刀（Thief sampler）：樣式與採樣刀類似，由內外雙層不銹鋼材質組成，上面有缺口供廢棄物進入並儲存之（如圖例七）。
（3） 採樣鏟（Shovel）：不銹鋼材質製，規格從大至小，大型者如水泥拌合用，小型者如園藝用（如圖例八），亦可使用適當大小之可棄式不銹鋼匙代替。
（4） 鑽土採樣組（Auger）：不銹鋼製螺旋狀中空採樣管，由配合不同土壤性質種類之各型螺旋狀刀（如圖例九）組成，可以手鑽入或配合電源供應以電（氣）動式鑽入取樣。除可棄式採樣器材外，使用後應先以毛或鋼刷（鋼刷只能使用於不銹鋼材質採樣器材）刷洗附著物，再以清潔劑、自來水洗滌數次，最後以蒸餾水淋洗晾乾。
4-5.2
Sampling Strategies
l
Three-dimensional sampling grid used for drums and tanks (Fig.
4.8)
(一) 單一隨機採樣
1.
採樣方式: 將所有廢棄物劃分成相當之假想格子，依序給予連續編號，再以亂數表選擇所要的樣品。
2.
特性: 廢棄物中之任一點，都有同等之機會被取出，且以隨機方式取出適量樣品。
3.
適用性: 適用於化學性質呈現不規則的不均一性，且維持固定狀態的廢棄物，或無任何或很少污染物分布資料的廢棄物。
4.
優點: 簡單，準確度高，精確度高。
(二) 分層隨機採樣
1.
採樣方式: 廢棄物之污染性質很明顯地分割成數層，且層與層間差異很大，而每一層間差異很小，並至少可取出2至3個樣品時，在每一層中，個別以單一隨機採樣，若清楚了解每層之差異程度，則依各層比例決定樣品採集量。
2.
特性: 依據各層顯著的差異性，依其差異程度取出不同比例之樣品數。
3.
適用性: 適用於很清楚地知道廢棄物中污染物的分布情形，且其分層現象很明顯的情況下。
4.
優點: 對廢棄物分布情況估計正確時，期準確度和精確度都較單一隨機採樣法為高。
5.
缺點: 若廢棄物分層現象不明顯，且估計錯誤時，則會降低其準確度和精確度。
(三) 系統隨機採樣
1.
採樣方式: 在廢棄物中隨機取出第一個樣品，其後在一定空間或時間間隔下，依序取出其他樣品。
2.
特性: 第一個樣品隨機取出後，其餘的樣品則依一定規則取出。
3.
適用性: 適用於當廢棄物中之污染物質，任意分布或只有少許的分層現象。
4.
優點: 亦於確認和收集樣品，有時可得較高的精確度，若污染物分布較均勻時，則可得更高的精確度。
5.
缺點: 若污染物質的分布有未知的趨勢或循環時，則會降低其準確度和精確度。
(四) 權威性採樣法
1.
採樣方式: 由非常清楚所欲採集廢棄物特性的人員決定並選擇樣品。
2.
特性: 整個採樣過程完全由一個人決定，人為因素較強烈。
3.
適用性: 僅能適用於對廢棄物性質非常清楚的人員。
4.
優點: 較方便。
5.
缺點: 易造成錯誤的判斷，數據的有效性較可疑。
4-6
Sampling Away from the Source
4-6.1
Sampling and Monitoring of Air and Volatile Emissions
l Real-time Air
Monitoring
l Air Sample
Collection and Concentration
4-6.2
Groundwater Sampling
l
Borehole Drilling
l
Auger Method
l
Mud Rotary Drilling
l
Reverse Circulation Rotary Drilling
l
Air Rotary Drilling
l
Cable Tool Drilling
l
Jetted Well
l
Drive-point Well
l
Well Casings and Screens
l
Filter Packs
l
Monitoring Well Development and Sampling
4-7
Priority Pollutant and Sampling Analyses
l Gas Chromatograph
(GC)
uFlame ionization detector (FID):非鹵素揮發性有機物
uElectron capture detector (ECD)
uMass spectrometers (MS)
l High-Performance
Liquid Chromatography (HPLC): Low-volatility organic pollutants
l Atomic Absorption
(AA): Metals
l Inductively Coupled
Argon Plasma (ICP): Elemental analysis
4-8
Summary of Important Points and Concepts