Unit 5 In－situ Ground Water Bioremediation
1. Definition: In-situ ground eater bioremediation is a technology that encourages growth and reproduction of indigenous microorganisms to enhance biodegradation of organic constituents in saturated zone.
原位地下水生物修复技术是在饱和区哪，利用原有微生物的生长和繁殖来增强有机组分生物降解的一项技术。 2． Application
(1) for the full range of petroleum hydrocarbons
(2) be combined with other saturated zone remedial technologies and vadose zone
remedial operations. 3. Operation Principles (1) mitigate 缓和、减轻 (2) smear 弄脏，涂污 (3) vadose 地下水位线以下 (4) bioventing (5) upgradient
(6) infiltration gallery
(7) closed-loop 闭环路、闭合回路
(8) Bioremediation generally requires a mechanism for stimulating and
maintaining the activity of the microorganisms. (9) delivery system: an electron acceptor(oxygen, nitrate) nutrients (N,P) energy source (carbon) 4. System design
(1) In-situ bioremediation can be implemented in four treatment modes:
aerobic,anoxic,anaerobic and co-metabolic. (2) aliphatic hydrocarbons: 脂肪烃 aromatic hydrocarbons: 芳香烃 (3) chlorinated solvent: 含氯的溶剂 (4) hydrogen peroxide： 过氧化氢（双氧水） (5) Key parameter:
a. hydraulic conductivity of the aquifer
b. biodegradability of the petroleum constituents
c. location of petroleum contamination in the subsurface (6) silt 淤泥 clayey 多粘土的 (7)stratification: 成层；分层‘地层 stratum (pl. strata): 地层，层 (8) recalcitrant 反抗的，固执的
In-situ Ground water bioremediation— A citizen’s Guide to Bioremediation
1. What is Bioremediation ?
Bioremediation allows natural processes to clean up harmful chemicals in the
environment.
Harmful chemicals microbe water + harmless gases 2. How does it work?
Conditions: allow the microbes to grow and multiply
Condition modification: pump air, nutrients, or other substances, right
temperature, dig up, stir. 3. Is bioremediation safe? Bioremediation is very safe.
(1)It relies on microbes that naturally occur in soil. These microbes are helpful and pose no threat to people at the site or in the community. (2)No dangerous chemical are used in bioremediation.
4. How long will it take?
The time it takes to bioremediate a site depends on several factors. (1) types and amounts of harmful chemicals present. (2) Size and depth of the polluted area. (3) Type of soil and the conditions present
(4) Whether cleanup occurs above ground or underground----from a few months to
even several years 5. Why use bioremediation?
(1) Polluted soil and ground eater can be cleaned at the site without having
to move them somewhere else. ————————————————safe (2) Bioremediation does not require as much equipment or labor as most other
methods. ——————————————————————cheap
Unit 6 Taking Toxics Out of the Air
Introduction
The air we breathe van be contaminated with pollutants from factories, vehicles,
power plant and many other sources
Harmful effects: on people’s health and environment
Factors of the impact: quality, duration, potency, toxicity of the chemicals,
frequency, person’s state, etc.
What Are Toxic Air Pollutants?
Toxic air pollutants are those pollutants that are known or suspected to cause
cancer or other solution health effect, or to cause adverse environmental effects.
Where Do Air Toxics Come From?
Mobile sources: cars, buses, trucks Manmade sources: Stationary sources: factories, refineries, power plant Natural sources: Forest fires
Major sources: emit 10 tones per year of any of the listed toxic air pollutants, or 25 tons per year of a mixture of air toxics.
Area sources: consist of smaller sources, each releasing smaller amounts of toxic
pollutants into the air.
Emit less than 10 tons per year of a single air toxics.
Where Do Air Toxics Go?
Once released, toxic pollutants can be carried by the wind away from their resources to other locations, degrade, remain airborne, or deposit to land or water. Some toxic air pollutants may be persistent or never degrade. How Are People Exposed to Air Toxics?
Health risk can be caused by toxic air pollutants: 1．Breathing contaminated air
2. Eating contaminated food products: fish, milk, meat, eggs, etc. 3. Drinking water contaminated by toxic air pollutants
4. Eating contaminated soil.
5. Touching (skin contact) contaminated soil, dust, or water.
Additional Materials
专业英语（环境工程）教案
