Từ kết quả nghiên cứu đáy các bãi rác cho thấy hầu hết các bãi rác chưa được xây dựng đúng tiêu chuẩn. Hệ số thấm của nền đất dưới các bãi rác khoảng 106 đến 104 cms chưa đạt yêu cầu kỹ thuật. Hầu hết các bãi rác đều gây ô nhiễm môi trường nước xung quanh và vượt ngưỡng yêu cầu so với quy chuẩn nước thải của bãi chôn lấp chất thải Mô hình lan truyền bằng thực nghiệm và Geoslope đều cho thấy tầm quan trọng của lớp đáy bãi rác, với độ chặt lớn, hệ số thấm nhỏ có khả năng kìm hãm và ngăn chặn được các chất ô nhiễm. Tuy nhiên nước thấm qua đất dung trọng 1,55 (gcm3); 1,6 (gcm3); 1,65 (gcm3) có nồng độ COD, chì và cadimi vẫn vượt ngưỡng cho phép. Nước thấm qua đất có dung trọng 1,7 (gcm3), đạt 98% độ chặt tiêu chuẩn có nồng độ COD đạt tiêu chuẩn so với quy chuẩn nước thải của bãi chôn lấp chất thải, tuy nhiên vẫn vượt ngưỡng so với tiêu chuẩn nước mặt và nước tưới tiêu, gấp 410 lần. Nồng độ chì, đồng và kẽm đạt tiêu chuẩn cho nước sinh hoạt và tưới tiêu. Nồng độ cadimi vượt ngưỡng so với tiêu chuẩn cho nước sinh hoạt. Kết quả mô phỏng sự lan truyền chất ô nhiễm theo chiều sâu dưới đáy bãi rác bằng Geoslope cho thấy với nền đất được đầm chặt đạt hệ số nén K98, hệ số thấm đạt khoảng k = 109 cms: thì chất ô nhiễm không bị phát tán hoặc phát tán với độ sâu rất nhỏ dưới 10m
Practical methods assessment of risk related to transportation of dangerous goods by pipelines Mieczysław Borysiewicz Centre of Excellence „MANHAZ” Institute of Atomic Energy , Otwock-Świerk The risk connected with transportation ¾ ¾ Main hazardous related to transportation of liquid (oil or refining products) in case of leakage is derived from flammable and toxin substances Flammable is of great importance for safety whereas toxic is dangerous for environmental It’s necessary to take into account many elements while consideration of hazardous sources The most important are: Physical-chemical substance properties, connected with flammable and toxic – it’s necessary to consider components of product in detail Size leakage depends on: diameter of pipeline, product density, pressure in pipeline, topography and duration time of leakage, material properties and mechanisms of damages, which are factors forming leakage, reaction time, valves, drainage size, modeling fire and explosion, modeling heat effects (leakage size, fire, danger zones) Frequency of failures pipelines for derivatives of liquid oil substances Table 1A A Frequency failures petroleum pipelines of thickness from to mm Reason failure Appear damages / 1000 km-year Percent Leak Hole Crack Whole Mechanism damage 0,07 0,056 0,017 0,143 19,4 Operating errors 0,023 0,018 0,006 0,047 6,4 Corrosion 0,042 0,033 0,01 0,085 11,5 Natural hazard 0,006 0,005 0,002 0,013 1,8 Outside impact 0,218 0,173 0,054 0,445 60,9 0,359 0,285 0,089 0,773 100 49 39 12 - 100 TOTAL % Frequency of failures pipelines for derivatives of liquid oil substances Table 1B B Frequency failures petroleum pipelines of thickness from to 10 mm Reason failure Appear damages / 1000 km-year Percent Leak Hole Crack Whole Mechanism damage 0,07 0,056 0,017 0,143 34,2 Operating errors 0,023 0,018 0,006 0,047 11,2 Corrosion 0,042 0,033 0,01 0,085 20,2 Natural hazard 0,006 0,005 0,002 0,013 3,1 Outside impact 0,064 0,051 0,016 0,132 31,3 0,206 0,164 0,051 0,42 100 49 39 12 - 100 TOTAL % Table 1C Frequency of failures pipelines for derivatives of liquid oil substances C Frequency failures petroleum pipelines of thickness from 10 to 15 mm Reason failure Appear damages / 1000 km-year Percent Leak Hole Crack Whole Mechanism damage 0,07 0,056 0,017 0,143 45,9 Operating errors 0,023 0,018 0,006 0,047 16,4 Corrosion 0,042 0,033 0,01 0,085 29,5 Natural hazard 0,006 0,005 0,002 0,013 3,3 Outside impact 0,007 0,006 0,002 0,015 4,9 0,148 0,118 0,037 0, 303 100 49 39 12 - 100 TOTAL % Frequency of failures pipelines for derivatives of liquid oil substances Table Frequency failures petroleum pipelines in depend on deep pipeline Reason failure Deep of pipeline 0,9m 1,5m 2m 3m Mechanism damage 0,143 0,143 0,143 0,143 Operating errors 0,047 0,047 0,047 0,047 Corrosion 0,085 0,085 0,085 0,085 Natural hazard 0,013 0,013 0,013 0,013 Outside impact 0,132 0,099 0,066 0,0013 TOTAL 0,42 0,387 0,354 0,289 Estimate velocity discharge For velocity discharge from pipeline transportation liquid have impact coefficients such as: ¾ size hole, ¾ type of substance, ¾ pressure discharge, ¾ hill pipe, ¾ time cut off Failure scenarios Mechanism starting physical effects as a result of failure pipeline on diagram is shown Scenarios of failures The scenarios can be split into two groups: ¾ scenarios leading to fires and explosions ¾ scenarios leading to pollution of environment (ground water, wet ground, soil) One can get probabilities of individual scenarios by defining data determining probabilities of particular environmental conditions and applying quantitative principles of analysis of events tree Examples calculation for fires Table Pool fire of petrol – late ignition Hole diameter Soil type Velocity discharge (kg/s) Pool area (m) 406mm Medium clay 205 205 100 100 78 78 126 126 324mm Medium clay 164 100 78 126 219mm Medium clay 100 100 85 100 70 78 110 126 168mm Medium clay 30 46 45 65 10mm Medium clay 53 53 19 73 25 63 30 96 Length of flame (m) Zone radius for 10kw/m2 (m) Examples calculation for fires Tabel Pool fire of petrol – Early ignition Hole diameter Velocity discharge (kg/s) Pool area (m) Length of flame (m) Zone radius for 10kw/m2 (m) 406mm 205 68,9 60 91,2 324mm 164 62 56 83 219mm 100 48 47 67 168mm 30 26 31 40 10mm 5,3 11 17 19 Examples calculation for fires Table Probability of ignition sources Rural/ urban area Rural/ urban area Rural/ urban area Crack Leakage – big hole Leakage – small hole Early 1.55% / 3.1% 1.55% / 3.1% 0.31% / 0.62% Late 1.55% / 3.1% 1.55% / 3.1% 0.31% / 0.62% Total 3.1% / 6.2% 3.1% / 6.2% 0.62% / 1.24% Type of ignition Probabilities for failure scenarios ¾ Examples of event trees for leakages of petrol forming pool are shown on diagrams below ¾ Probabilities of different scenarios generating by these trees are also shown Probabilities for failure scenarios ¾ Events tree for pipeline rupture and medium hole (rural) Probabilities for failure scenarios ¾ Events tree for leakages (rural) Probabilities for failure scenarios ¾ Events tree for pipeline rupture and medium hole (urban area) Probabilities for failure scenarios ¾ Events tree for leakages (urban area) Hazard of environment Releases of hydrocarbon fuel from pipelines can cause different consequences for: • • • • • • human safety and health resources of wet ground waters biological life in water and soil surface water soil and geology using rural terrain etc Modeling pollutants in porous media • Those models are based on simple hydrologic interpretation, including assumption about homogeneous flow in ground water in given direction and homogenous parameters • Example of that model is a simple model of hydrocarbon pools, HSSM [Charbeneau Randall J., Weaver James W., Lien Bob K., Kerr Robert S., US EPA, The hydrocarbon Spill Screening Model (HSSM), 1995], available in Institute of Atomic Energy in Swierk Modeling pollutants in porous media • In that model there is assumption that hydrocarbon substances are discharged nearly ground surface and transported down through aeration zone up to level of ground water • On the level of ground water a hydrocarbon lens arises, which is spread in horizontal direction Components of hydrocarbon lens are dissolved in ground water flowing under the lens These components arise stain, which can pollute wells and other sensitive receptors which are located in flow direction • HSSM can be used to calculate transport pollutants depending on quantity of light liquids in non-aqueous phase liquid, coefficients of phases distribution, velocity flow of ground water etc The results of this model should be taken as rough approximation, as many other approximations have been used in the model Modeling pollutants in porous media • Another considered physical problem is pollutions of porous media in case of discharge of organic substances – the so-called nonaqueous liquid phase (NAPL) in under surface heterogeneous granulated soils • The organic liquids can be lighter than water (LNAPL i.e., based on hydrocarbon petrol) or heavier than water (DNAPL i.e., based on chloral hydrocarbon) Modeling pollutants in porous media Three basic mechanisms of spreading pollutants of organic liquids on upper layer ground are: • penetrating in porous media in vertical and horizontal directions caused by gravity and capillary forces • decay and in consequence advection in falling direction including precipitating of source in aeration zone In case of organic liquids heavier than water, their components are picked out by wet ground • transport evaporated components in gas environment of soil, where increase of density of gas causes motion down Division between pollutants phases: aqueous and gas additionally increases potential of components which causes particles migration • The spreading pollutions NAPL in under surface groundcaused by surface realase Modeling pollutants in porous media • The example of compound model which take into consideration all three mechanisms of transport pollutants that can be used to calculate pollutions of soil and ground water as a result of release of oil derivates is a model applied in computer program NAPL Simulator [Guarnaccia Joseph, Pinder George, Fishman Mikhail, Kerr Robert S., US EPA, EPA/600/R-97/102, NAPLSimulator, 1997], applied in Institute of Atomic Energy in Swierk too] ... damage 0, 143 0, 143 0, 143 0, 143 Operating errors 0, 047 0, 047 0, 047 0, 047 Corrosion 0,085 0,085 0,085 0,085 Natural hazard 0,013 0,013 0,013 0,013 Outside impact 0,132 0,099 0,066 0,0013 TOTAL 0 ,42 0,387... 0,056 0,017 0, 143 19 ,4 Operating errors 0,023 0,018 0,006 0, 047 6 ,4 Corrosion 0, 042 0,033 0,01 0,085 11,5 Natural hazard 0,006 0,005 0,002 0,013 1,8 Outside impact 0,218 0,173 0,0 54 0 ,44 5 60,9 0,359... 0,017 0, 143 45 ,9 Operating errors 0,023 0,018 0,006 0, 047 16 ,4 Corrosion 0, 042 0,033 0,01 0,085 29,5 Natural hazard 0,006 0,005 0,002 0,013 3,3 Outside impact 0,007 0,006 0,002 0,015 4, 9 0, 148 0,118