Main idea

There is a general concept that water can carry away and process all the waste people produce. However, this is not true anymore. Watercourses are overpolluted, because we discharge too much waste and too many substances in the water and, therefore, the natural capacity of waterbodies to clean themselves is overburdened.

Goal

Pupils identify the main pollutants, and they learn that there are different kinds of wastewaters. The goal is to explain that some of the aquatic organisms are not able to survive in polluted water, and hence, compared to clean waters, other species inhabit polluted waters. Such species are called “bioindicators” (see Chapter 5). Knowledge of the living conditions preferred by different species in rivers enables us to determine the water quality of watercourses and rate their pollution.

Concepts

wastewater, natural/artificial pollution, bioindicators → living conditions

Introduction: Water Use?

Have a discussion with pupils about water use, reuse and discharge:

  • Think about what we all need water for?
  • Where does the used/polluted water go?
  • Is it still drinkable after use?
  • What do we call it? (wastewater)

Activities in this lesson

Quantities of wastewater
4.2.1
Subject: Math, Social skills
Age group: 7 - 9, 10 - 12, 13 and up
Type of activity: Debate, Project
Number of participants: Individual
What Can we Find in Storm Water
4.2.2
Subject: Biology, Chemistry, Health care and recreation
Age group: 13 and up
Type of activity: Experiment
Number of participants: Team
Polluters and Pollution (experimenting with different types of pollution)
4.2.3
Subject: Biology, Chemistry, Health care and recreation
Age group: 13 and up
Type of activity: Experiment
Number of participants: Team
How Much is too Much Pollution?
4.2.4
Subject: Biology, Chemistry
Age group: 13 and up
Type of activity: Debate
Number of participants: Individual, Paired, Team

Discussion: How to Reduce the Production of Wastewater?

Go with students through the whole man-made water cycle again and try to list as many possibilities of reducing the quantity of wastewater without compromising hygiene and other needs.