Narrator: Listen to part of a lecture in an environmental engineering class.

旁白：听一段环境工程学的演讲。

Professor: At the end of yesterday's class, we were discussing landfills and the hundreds of millions of tons of everyday garbage which are deposited into them each year in the United States.

教授：在昨天课程的尾声，我们在讨论在美国的垃圾填埋场以及每年每天成千上万吨倾倒在其中的垃圾。

It's a growing problem. Quite simply, we are running out of space to put our garbage.

这是一个越来越严重的问题。非常简单的是，我们可以放垃圾的地方都快用完了。

And this is especially true for solid organic waste: food scraps from home or food processing plants, waste from farms, that sort of thing.

这个对于固体有机垃圾来说尤其正确：家里或者食品加工厂的残羹剩饭、农场的垃圾等。

Did you know that two thirds of the waste sitting in our landfills is organic material?

你知道2/3在垃圾填埋场里的垃圾是有机的吗？

We have government recycling programs for materials like plastics, glass and metal, yet widespread solutions for organic waste materials haven't really been addressed in the United States.

我们有政府回收项目区回收塑料、玻璃和金属等的材料，但是在美国广泛用于处理有机垃圾的方案还没有真正地制定出来。

I think this is just asking for trouble in the future.

我觉得这个对于以后来说是会带来麻烦的。

So today I want to talk about a technology that offers a potential solution to the proble--Anaerobic Phased Solids digestion, or APS digestion.

因此，今天我谈谈一个可能解决这个问题的一项科技——厌氧分阶固体消化，或简称APS消化。

First of all, what does anaerobic mean? Anyone?

首先，厌氧的意思是什么？有人知道吗？

Student: Without oxygen?

学生：没有氧气？

Professor: Correct!

教授：正确！

APS digestion uses anaerobic bacteria, ones that thrive in the absence of oxygen, to consume, to break down organic material.

APS消化用在缺氧情况下存活的厌氧细菌，去消耗，去分解有机物质。

Student: Excuse me. Professor. Um…those anaerobic bacteria you are talking about…well, aren't anaerobic bacteria also used in waste water treatment plants?

学生：请问，教授，这些你说的厌氧细菌是不是在废水处理厂也使用的厌氧细菌？

Professor: Yes. In fact, they are.

教授：是的。

Would you like to explain this to the class?

你可以和班级其他同学解释一下这个吗？

Student: Sure! So when waste water is treated, one of the byproducts is a thick liquid called sludge.

学生：当然可以。当废水被处理的时候，有一个粘稠液态的副产品叫做污泥。

And aren't anaerobic bacteria used to break down the sludge?

厌氧细菌是不是用来分解污泥的呢？

Professor: That's right.

教授：正确。

Anaerobic bacteria have been used in waste water treatment for decades.

厌氧细菌在污水处理中已经被使用几十年了。

Student: So how is this technology different?

学生：那么这个技术有什么不同？

Professor: Good question.

教授：好问题。

The anaerobic digestion systems used in waste water plants are designed to treat sludge, not solids.

在废水处理场使用的厌氧消化系统是为了处理污泥而设计的，而不是固体。

Now, in the past, researchers have attempted to treat solid organic waste with that same equipment.

在过去，研究者们试图用同一套设备去处理固体有机垃圾。

But there was always a problem.

但是总是有一个问题。

In order to process the solid waste, the kind we find in landfills, you had to pretreat the solids to turn them into sludge.

为了去处理这些那些我们在垃圾填埋场发现的固态垃圾，你必须预先将这些固体转化为污泥。

First, by breaking the material apart mechanically into small particles and then adding a lot of water until you got a kind of thick, soupy mix that the equipment could handle.

首先，从物理上地将这些材料分割成小的颗粒，然后加水直到变成机器可以处理的浓稠的像汤汁一样的混合物。

But that extra step took time and required a lot of energy.

但是额外的步骤是很费时间和精力的。

Student: That sounds like it would cost a lot.

学生：这听上去真的很费时费力。

Professor: That's right.

教授：对的。

But APS digestion is designed specifically to handle solid waste.

但是APS消化是为了处理固态垃圾而设计的。

So it is much more cost-effective.

因此它更加省钱。

The new technology processes organic waste in two phases.

这个新的技术通过两个阶段来处理有机垃圾。

Remember, APS stands for Anaerobic Phased Solids digestion.

记住，APS代表的是厌氧分阶固体消化。

First, the waste material is loaded into a large, closed container, along with different types of anaerobic bacteria.

首先，垃圾会被装进一个含有各种厌氧细菌的大的容器中。

The bacteria break the solids down into acids and hydrogen gas.

这些细菌将固体分解成酸和氢气。

The hydrogen is extracted and the remaining acids are transferred into a different container for the second phase of the process.

氢气会被引出而剩下的酸会被转移到另一个容器，进入第二个阶段的处理。

There another type of bacteria converts the acids into methane gas.

那里有另外一种细菌将酸转化成沼气。

Student: Aren't hydrogen and methane gas bad for the environment though?

学生：可是氢气和沼气对环境不是有坏处吗？

Professor: The answer in this case is no, because they don't escape into the atmosphere.

教授：在这个情况下的答案是否定的，因为他们并不会逃到大气中去。

The gases are captured and can be burned to produce electricity, which saves a lot of money and ultimately decreases our need for fuels like petroleum and coal, which are not only expensive but are also polluting.

这些气体会被捕获并用来生产电力，这个可以节约很多钱并且最终减少我们对于燃料的需求，如石油和煤炭，这些燃料不仅贵而且很有污染性。

Student: So organic waste from landfills could be processed this way?

学生：所以在垃圾填埋场的有机物可以这样处理？

Professor: It is certainly one possibility.

教授：这当然是一种可能性。

And APS digestion systems are very versatile.

并且APS消化系统是非常多元化的。

They can be installed just about anywhere.

他们可以在任何地方安装。

See, anaerobic digestion systems used at waste water treatment plants are huge tanks that hold thousands of gallons of waste water.

看，在废水处理厂中的厌氧消化系统是装有几千加仑废水的巨型蓄水池。

But the APS containers are small enough to be set up on site, where the waste is generated, like at food processing plants or on farms.

但是APS容器足够小可以被安装在垃圾产生的现场，比如说在食物加工厂或者在农场。

So garbage doesn't have to be transported long distances.

因此，垃圾不用被长途运输。

As a matter of fact, a couple of universities successfully set up demonstration projects.

事实上是，很多大学成功地创立了示范项目。

They collected food scraps from dining halls and local restaurants and process them in APS facilities.

他们从食堂和当地饭店收来残羹剩饭并将它们用APS仪器处理。

Not only did the university save money, we are also learning even more about the APS process.

大学不仅节约了钱，而且还学到了更多关于APS处理的信息。

What is the next step forward?

那么下一步是什么呢？

Well, APS digestion uses several different types of anaerobic bacteria, right?

APS消化使用各种不同的厌氧细菌对不对？

So what are the most efficient bacteria in the process?

因此，在这个过程中什么细菌才是最有效的呢？

If researchers can figure that out, the highest performing bacteria mix for a system could be determined.

如果研究着可以指出，对于系统来说最高效的细菌是可以定下来的。

Ultimately the goal would be to grow enough of these particular bacteria to support large-scale commercial APS systems.

最终的目标是去培养足够的这种细菌去支持大范围的商业APS系统。