Membrane Water Filtration System
Internal pressure type

■ Filtration system
Raw water is supplied through the raw water pump to the membrane module. The circulating pump generates a circulation flow, thereby ensuring a sufficient flow over the surface of the membrane. This reduces the amount of sludge and other suspended substances that accumulate on the surface of the membrane, extending the period between physical washings, and enabling the system to handle highly turbid raw water without any difficulty.

1. The filtration process is being mentioned for the first time here, so it would probably not be a good idea to use the definite article. The definite article points out that this topic has appeared or been mentioned before.
2. I think the preposition "for" works better here.

1. I think the singular form of this word is generally used in cases like this (suspended matter).
2. The preposition isn’t needed here.
3. This should be "highly turbid."

1. I think this segment would be easier to understand if you put a comma between these words.
2. This segment is a bit hard to understand. I think the word "that" creates a clause that is an incomplete thought. Perhaps this could be simplified to say something like "…by preventing suspended substances from accumulating on the membrane surface…"

1. As we discussed in class, the interpretation of this passage is backwards. The issue is not the length of the cleaning period becoming longer, but rather, the interval between cleanings can become longer.

○ 浄水
手段 ： filtration, evaporation, sedimentation, reverse osmosis (desalination)...
結果 ： purification

○ 水道水
上水道 : clean water, running water, tap water (potable)
中水道 : gray water
下水道 : black water

In New Orleans after Katrina, it took two weeks to recover running water.

○ 問題なく
without problem よりも without (any) difficulty が無難。
「問題」には必ずしもこだわらず、successfully… あるいは ensure successful… という方向に考える。

■ Cleaning system
Physical cleaning
Physical cleaning Filtration is done by pumping raw water supplied by the raw water pump through the hollow fiber. The raw water is forced from the inside of the hollow fiber through the walls to the outside. As the filter gradually becomes clogged from continuous use, physical cleaning is carried out at regular intervals. This cleaning is conducted by water from the backwash pump being passed from the outside of the membrane to the inside of the membrane, washing away the grit and other impurities adhering to the membrane. The cleaning substantially restores the membrane to its initial condition. However, as there may be substances clogging the membrane that backwashing is unable to remove, causing the obstruction to progressively worsen, regular cleaning of the membrane with chemicals should be carried out.

Chemical cleaning
If the membrane is in use over an extended period of time, substances that cannot be removed by backwashing will gradually accumulate and lead to clogging, and an increase in the transmembrane pressure difference. Regular chemical cleaning must be performed to clear away whatever obstructing substances backwashing has been unable to remove.

1. Two things about this segment. First, I think the word "permeate" is too passive. I think the basic idea here is to describe that water is forced through or pumped through the membrane; not merely permeate. Second, since the word "permeate" means to pass through, the word "through" is redundant.
2. I think what is described here is wrong. You are saying that the clogs are washed (or cleaned). Why would the clogs be washed with chemicals? Is there some reason to have clean clogs? I think what you need to express is that the clogs are removed through washing or that clogs are washed away; not that the clogs are washed.

1. I think the word "supplying" is too weak; it doesn't express any action. The basic idea here is that raw water is pumped or forced through the fibers by the raw water pump.
2. It is not really clear what the word “which” is connected to. Do you mean to say that the membrane needs to be removed? Doesn’t the text say that the substances that clog the membrane need to be removed?
3. This should be "…performed at certain intervals."
4. The construction of this segment is a bit awkward. The use of "is" doesn't feel right. I think it would be sufficient to say "The physical cleaning is done by introducing water from …"
5. It's not exactly clear what "loadings" refers to. Does it refer to substances that clog the membrane? Or accumulated impurities?

1. I think the correct preposition here is "at" regular intervals.
2. Is it clear what "Its" refers to? To me, it is unclear whether you are referring to physical washing, membranes, or clogging.
3. This needs to be changed a little. Right now, it may give the reader a mistaken idea of the degree of restoration the membrane undergoes. The membrane is restored to almost its initial level of performance. If you say that the membrane is almost restored, it means that it does not work at all - that restoration failed.
4. Check a grammar book on the usage of which and that.

1. I think this would sound better if you used "…as it becomes plugged after a long…"
2. This sounds a bit weak. I think the Japanese text says that the function is restored to almost the original or initial level of performance.
3. This is probably all right, but to me, it wasn't quite clear what "advanced stage" refers to.
4. I think this would be clearer if you put the definite article in front of "entrapped."
5. This segment doesn't flow quite as smoothly as it should. Perhaps it could be modified to something like "…across the membrane to a point where backward flushing is insufficient to clean the membrane."

1. This sounds a bit odd. I think it would read more smoothly if you said something like "…causes the fibers to gradually become clogged.." or "…causes the fibers to gradually clog…"
2. Do you think that "flows" expresses enough action? It seems a little passive to me. I think that since you already used "pump" as the verb, the word "flow" is not necessary. Also, if you use "flow" here, the water just moves around the filter and is not really forced through it. So the image is rather weak.
3. Is it possible to operate a membrane? Perhaps a different verb would be better here. I think you could simply say "use."

○ 一定周期、定期的
cleaning at regular intervals ---- たとえば「毎月」
periodic ： blood tests ---- たとえば「年に５回」（多少あいまい）

○ 水を供給して
pumping water through …
water is forced from … through …

ポンプが用いられるため、supply、flow、permeate などでは不十分（too weak、passive）。

○ 行います
is done, is carried out, is conducted

■ The shape of the membrane and the membrane module

Water purification by means of a membrane is one type of solid-liquid separation technology, in which impurities in the water are removed by using pressure to pass the water through the microporous membrane. This process is capable of removing suspended sludge and bacteria, while ultra filtration membranes are able to remove viruses. Membranes manufactured by Maezawa are made of cellulose acetate with hollow fiber ultra filtration membranes with a molecular weight cut-off of 150,000. To facilitate the process of passing water through the membranes under pressure, the membranes are packed into a cylindrical housing to increase the packing density, providing a module membrane with a very large surface area.

1. This phrase is a bit of a problem because it sounds as though ultrafiltration membranes are used for removing suspended matter, bacteria, and viruses. The original text is emphasizing the role of the ultrafiltration membrane is filtering out only viruses.
2. I think the logic here may be wrong. Does the original text say that Maezawa uses ultrafiltration membranes or does it say that membranes made by Maezawa are made of acetate cellulose with molecular weight of 150,000?
3. I'm not quite sure what you mean by more intensive filtration. Perhaps this could be expressed in another way?

1. I don't quite agree with the idea that pressure is applied on the membrane. I think pressure is applied to the water to force it through the microporous membrane.
2. Care should be taken when using the "not only…but also…" form. In this case, you are implying that suspended matter, bacteria, and viruses are all removed by using an ultrafiltration membrane. But actually, the ultrafiltration membrane is used to remove viruses, not suspended matter or bacteria.

1. As we discussed in class, the position of the term "ultrafiltration membrane" is very important. This sentence implies that this ultrafiltration membrane is used to filter out substances, bacteria, and viruses, but this is not true. It is used to filter out only viruses.

1. Does this term sufficiently convey the size of the pores of the membrane? I think it is important to mention that the membrane has microscopic pores. I'm not so sure that the term "semi-permeable" conveys the same type of information.
2. Although I know this is the unit of measure for molecular weight, is this generally-used term? Is it more common to leave this term out or is it usually included in a description?
3. What exactly do you mean here by "good permeate water"? Does "good" refer to quality? Is this clear from the context of the sentence?

1. This structure implies that the ultrafilter membrane is used to filter out suspended substances, bacteria, and viruses. Is this true? Or is the ultrafilter membrane used only for the removal of viruses?
2. This segment is a bit awkward. It may be easier to understand if you simply this part of the sentence. You could say something like "…the membranes are packed into a cylindrical container in order to increase…"

○ 不純物
impurities ： 果たして不潔、不純といい切れるか？
substances ： これが中立で望ましいと思う。
obstructing substances, suspended substances, substances clogging…

おまけ

● 汚れ
stain ： シミ （特に繊維の中に入り込む、染まる）
smear ： 表面に擦り付けたような汚れ
grime ： ワイシャツの襟首の汚れなど （ring around the collar = collar soil）

ring around the collar は家事を放置している主婦を象徴することがある。

● dust と dirt
dust ： dry particles (wet dust = grime)
dirt ： 土（泥）

● information を可算で用いる場合
a piece (pieces) of info と学校で教わっていた。

「情報全体の一部」として a piece (pieces) of info は正しい。
「一片の情報」は an item (items) of info。

● piece
a piece of cake (very easy like eating one piece of cake) という表現は、日本語の「お茶の子さいさい」と同様に古い。

「頓知」という言葉をご存知の英語ネイティブがおられるが、これを知らない日本人もおり、やはり古い。今の日本語では「ウイット」とか言う。

● semicolon
日本語では「中黒」というものがあって便利に使われているが、翻訳は難しい。

例：「当店では書籍、CD、DVD、プラモデルの設計・製作・販売、人形、骨董を扱っています」
We handle: books; CDs; DVDs; design, production and sales of plastic models; dolls; and antiques.

またhoweverやthereforeは、本来 ; however,や ; therefore, の形で使う。

セミコロンは使い方が難しい。これを「スーパーカンマ」ということがある。

THE PRINCIPLE: The semicolon is perhaps one of the most abused symbols in the English language. Yet its general, two-fold purpose is simple and direct:

• Use the semicolon to separate two independent clauses (i.e., complete sentences) when there is no coordinate conjunction (and, or, but, for, yet, so) between them.
• Use the semicolon to separate items in a series in which commas are also present. In this usage, some have dubbed it the "super comma."

⇒ セミコロン

余談

● 過酷な西部、Sacramento, California
カリフォルニアの州都サクラメントは湿度が１桁％、気温は 118F (48℃) にもなる。