2.5 气味源 Odor sources

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在现代生活中,干扰市民生活的气味源通常来源于垃圾填埋场,废水处理厂,工业生产,商业活动等等。这些气味源和居民的抱怨,已经引起了各级政府的高度重视。相应的对气味控制的法规条例也相应出台。总之,政府对气味的控制和管理力度在不断的加强。Citizen complaints about odors caused by landfills, waste water treatment plants, industrial processes, and other sources have created a chain reaction through all levels of government as officials search for a sufficient odor regulation which creates consistent ways of defining, investigating, and enforcing a violation.

 

1. 在垃圾填埋场 In Landfills

垃圾填埋场是一个复杂的系统,在那,废物在一定的湿气,温度,和压力下,经自然的化学和生物反应作用下分解为基础的成份。气味就产生于这些化学和生物的反应过程。在无氧或低氧的条件下,有机物被不同种类的无氧微生物 (无氧反消化细菌,硫还原细菌,和产甲烷细菌)分解还原就是所谓的无氧消化和发酵反应过程,它们的最终产物氮气(N2),硫化氢(H2S) ,甲烷(CH4),二氧化碳(CO2)会在压力的作用下缓缓升至垃圾的表面,同时,在它们的分子表面会携带出其它的气味成份,如在废物腐烂的不同阶段所产生的气味,如各种挥发性有机酸 (VOCs),氨气(NH3),氮氧化物(NxOx),一氧化碳(CO)等等。在所有这些气体中,硫化氢,硫醇,和氨气只是其中的几种垃圾场产生的有毒气体而已。垃圾场中最普通最容易确定的气味问题发生在垃圾的表面。潮湿的物体因水气蒸发时也会带来一些气味问题。Landfills are a complex system of naturally occurring chemical and biological reactions that break the waste materials down into its basic components. The base odors are the result of these biological and chemical processes taking place in an environment of moisture, heat and pressure. In an anaerobic (low oxygen) reaction phase, the biological processes, including anaerobic respiration and fermentation that denitrifying bacterial, Sulfate Reducing Bacterial, and Methane Producing Bacterial involve in, release nitrogen, hydrogen sulfate, methane and carbon dioxide gases that slowly make their way to the surface of the landfill. Attached to these molecules, as they rise to the surface, are other odorous substances such as VOCs, ammonia, nitrogen oxides, monoxide, etc., resulting from materials with varying states of decay, which can compound the odor problems. Hydrogen sulfide, mercaptans and ammonia are just some of the other odorous and toxic gases that are produced in a landfill. The most common and easily identifiable odor problems in a landfill occur at or near the surface. Materials that are moist and wet can emit substantial amounts of odors as the moisture evaporates.

 

• 垃圾场有不同的气味源发出不同程度的气味Landfills can emit odors in varying degrees from many potential sources that may include:

1) 来往装运垃圾的卡车 Arriving and queuing hauling trucks

2) 现场的车辆和重型机械 On-site vehicles and heavy equipment

3) 可生物降解的家庭废物 Biodegraded household waste

4) 下水道污泥 Sewage sludge

5) 工作面 Working face

6) 扬起的有气味的灰尘 Fugitive odorous dust

7) 临时覆盖物 Temporary cover

8) 以覆盖的垃圾面 Capped cells

9) 垃圾表面道路建设 Access road construction

10) 渗漏液收集系统 Leachate collection systems

11) 渗漏液处理系统 Leachate treatment systems

12) 气体收集系统 Gas well construction

14) 气体井收集管 Gas wells and collection piping

15) 气体处理系统 Gas treatment systems

16) 气体火焰燃烧系统 Gas flares

17) 相关的垃圾填埋活动,如堆肥 Associated landfill activities, ie. yard waste and composting.

18) 临近的与垃圾填埋场不相关的商务活动 Adjacent unrelated landfill activities and businesses

 

• 每一个潜在的气味源,存在以下不同的释放方式:Each of these potential odorous sources varies in the following ways:

1) 释放种类(表面和点源)emission type (surface or point source)

2) 释放率(每秒气味单位)emission rate (“odor units” per second)

3) 气味强度(浓度和强度)odor strength (concentration and intensity)

4) 气味持续性(剂量反应关系)odor persistence (dose-response relationship)

5) 气味特点(描述符和快乐因子)odor character (descriptors and Hedonic Tone)

6) 发生频率(随机或重复)frequency of occurrence (random or repeating)

7) 释放持续的时间(释放或相关的活动)duration of emission (episode or activity related)

8) 环境状态(临时条件,紧急释放,施工等)circumstances (temporary condition, emergency release, construction, etc.).

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