I. Reading Exercises:

Exercise 1. Read and memorize using a dictionary:

neutralizing filters, acidic water, limestone chips, is dissolved, reverse Osmosis, treatment, decreases, content, contaminants, rejecting, pinholes, reflects, faucet spout, is supplied, a sediment prefilter, removes, in advance of, consumers, interferes, detergents, grains, cation-exchange water softener, is saturated, recharging, a brine solution

Exercise 2. Answer the questions:

1) What are neutralizing filters used for?

2) What is R.O. membrane capable of doing?

3) What does the simplest home R.O. system consists of?

4) What is hard water caused by?

5) What is the most common way to soften water?

Exercise 3. Open brackets choosing the right words:

A sediment prefilter and activated carbon prefilter or postfilter might be (used/included). The prefilter (makes/removes) sand, silt and sediments, while the activated carbon (rejects/removes) the organic materials and dissolved gases not treated by the R.O. membrane. Water softeners are (made/used) in advance of the R.O. system when household water is excessively hard.

The speaking module

II. Speaking Exercises:

Exercise 1. Describe "R.O." filtration systems for home water treatment.

Exercise 2. Ask questions to the given answers:

1) Question: ___________________________________________ ?

Answer: As the water passes through the filter bed, calcium carbonate is dissolved into the water and the water pH is increased, reducing its acidity.

2) Question: ___________________________________________ ?

Answer: Household R.O. systems typically treat 3 to 5 gallons of water per day.

3) Question: ___________________________________________ ?

Answer: The most common way to soften water is the cation-exchange water softener.

The writing module

III. Writing exercises:

Exercise 1. Complete the sentences with the suggested words:

Or; as; on; and; of; with; and; causes; are; is.

Hard water ______ caused by calcium and magnesium that ______ dissolved in the water. This ______ scale to form in hot water pipes ______ water heaters. It interferes ______ the cleaning action ______ soaps ______ detergents, and forms a film ______ skin, clothing and fixtures. Hardness is measured either ______ milligrams per liter ______ parts per million.

Exercise 2. Compose a story on one of the topics:

“Neutralizing filters”

“The simplest home R.O. system”

“The most familiar water conditioning system”

Lesson 5 the reading module Read the text: Renting Equipment and Using Bottled Water

In certain situations, purchasing water treatment equipment is not the best alternative. If the water has been contaminated by a spill, and permanent treatment is not required, renting equipment or buying bottled water are viable solutions.

Renting is a practical way to become familiar with the device prior to purchase. Renting allows you to determine maintenance requirements, costs and the effectiveness of the treatment system. Also, if you are renting your residence but you are not pleased with the water quality, equipment rental is reasonable. A rental agreement should clearly specify in writing the responsibility for maintenance, as well as any application of monthly rent to an eventual purchase. Insurance costs and periodic testing are other stipulations that need to be made.

Enforcement of chemical and microbiological standards for bottled water varies between states. Generally, standards for bottled water are no more stringent than those for public water systems. It is probably not cost-effective to purchase bottled water for health reasons when the normal supply is a municipal system, unless there is a health hazard within the home distribution system (such as lead pipes). There is no maintenance requirement with bottled water, nor any mechanical apparatus to operate, which appeals to some people.

Cost is a major determining factor in deciding to purchase or rent water treatment equipment, or to buy bottled water. The situation determines which may be less costly. Watch for hidden expenses such as separate installation fees or monthly maintenance fees. Additionally, the disposal of waste materials, such as reject water from reverse osmosis systems, spent cartridges from activated carbon units, and used filters, can add to the cost of water treatment and should be figured into the purchase or rental price.