Download Distinguishing Physical and Chemical Properties Lab

Name: ___________________________
Date: ___________
Distinguishing Physical and Chemical Properties Lab
Wastewater Treatment Plant
Background:
In general, a physical process can change a physical property of a substance but not its
chemical composition. In contrast, a chemical process causes a change in chemical
composition that result in the formation of a chemically new substance. Primary
treatment of wastewater consists of a series of processes that involved the use of
special equipment and techniques.
Objective:
This investigation is set up to allow you to explore the differences between physical and
chemical changes. In wastewater treatment, physical and chemical processes are used
at different points to clean up wastewater.
Directions:
Go to the following website and answer the questions below. Be sure to read each page
of the module.
http://techalive.mtu.edu/meec/module21/title.htm
Questions:
1. What is the goal of a wastewater treatment plant?
2. What are the major goals of wastewater regulations (laws)?
3. What pollutants are found in wastewater?
4. Describe the physical properties of raw wastewater (influent).
5. Distinguish between combined sewers and separate sewers.
6. What happens to the following in nature? Are they chemical or physical changes
(circle “P” for physical or “C” for chemical)?
a. P C Pathogens –
b. P C Solids –
c. P C Nutrients –
d. P C Organic Matter –
e. P C Toxic Materials –
7. What are the basic steps in wastewater treatment? After reading about each,
identify it as a chemical and/or physical process. Explain why it is chemical
and/or physical.
Step
Physical /
Chemical
Explanation
8. Explain the following two processes of secondary treatment. Identify whether
this involves physical and/or chemical changes.
a. Activated Sludge –
b. Clarifiers –
9. Describe tertiary treatment. Identify whether this involves physical and/or
chemical changes.
10. Describe disinfection treatment. Identify whether this involves physical and/or
chemical changes.
11. Solid waste from wastewater is called sludge. Processing it involves two steps:
digestion and dewatering. Explain what each step is and identify each as a
chemical or physical process.
12. What is an indicator that the anaerobic digestion of organic involves a chemical
change?
13. How is solid waste disposed of? Do you support these?
14. What two ways happens to digested sludge?
15. Describe the physical properties of treated wastewater (effluent).
16. Answer the questions on the “Where did it all go?” page.
a. Grit Chamber
i.
ii.
b. Bars, Racks, and Screens
i.
ii.
c. Sludge Disposal
i.
ii.
d. Anaerobic Digester
i.
ii.
e. UV Disinfection
i.
ii.