Essay on wastewater treatment plant

4.2 Back River/Patapsco Waste Water Treatment Plant
Goals & Objectives:
After completion of this activity students will be able to:

1. identify the role of municipal waste treatment facilities in the community;

2. discuss the effects of storm events on management of wastewater;

3. describe advanced levels of waste water treatment;

4. explain how pathogens are removed and the impact of that on the environment;

5. describe positive uses of sewage sludge;

6. discuss the regulations that apply to wastewater treatment; and

7. describe the role of environmental scientists in wastewater treatment or management.

8. Explain the steps of wastewater treatment.

Introduction:
From Google: eu·troph·i·ca·tion yo͞oˌträfiˈkāSHən/

noun

1. excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.

Treatment of municipal waste has evolved over the decades from simply allowing the effluent to enter water bodies and to be diluted, to trickling of waste water over gravel, to sophisticated systems that remove much of the nitrogen and phosphorus that would otherwise contribute to eutrophication. Waste water treatment plants (also called WWTPs or POTWs) vary in size and complexity depending on the size of the community served. Two important considerations for these plants are removal of biological hazards such as bacteria and removal of nutrients that would contribute to eutrophication.

The first step of most modern waste water treatment processes, called preliminary treatment, is to remove solid objects that have been flushed down toilets. In regions where sanitary and storm sewers are combined, other objects, such as twigs and leaves may enter through storm sewers that receive storm water runoff. These objects could damage the pipes through which the waste water flows.

After large solid objects have been removed, waste water continues to the next step, called primary treatment. Large suspended organic solids settle out as the water flows slowly through a series of long tanks. The resulting sludge has a high water content and its concentration (some water removed) takes place in special tanks using gravity.

Dissolved and fine suspended solids and nutrients must still be removed. This is done using bacteria during secondary treatment. This aerobic process allows most of the organic solids to be digested by microorganisms.

Tertiary treatment includes processes like chlorination that kills microorganisms, addition of chemicals to remove chlorine, and sand filtration to remove small particles. Biological Nitrogen Removal (BNR) and Enhanced Nitrogen Removal (ENR) further reduce the amount of nutrients in the effluent.

In this lab, students will watch a video of how the wastewater treatment process works, as well as gather information from links provided. You may need to do additional research to answer all of the questions.

Link to a Virtual Wastewater Treatment Plant Tour

https://www.youtube.com/watch?v=FvPakzqM3h8

Wastewater Plants Extract Nutrients from Sewage

https://www.voanews.com/a/wastewater-plants-become-green-factories/1531868.html

Information about the Waste Water Treatment Plants are available from the Baltimore Department of Public Works website at:

https://publicworks.baltimorecity.gov/pw-bureaus/water-wastewater/wastewater

Treatment Levels and Waste as Resourse

https://publicworks.baltimorecity.gov/pw-bureaus/water-wastewater/wastewater/patapsco/process

Heavy Rain and Runoff

https://publicworks.baltimorecity.gov/news/press-releases/2015-06-28-heavy-sustained-rainfall-leads-sewer-overflows

Drugs in Wastewater

https://www.cnn.com/2016/08/25/health/meth-fish-baltimore/index.html

Lab Activity:
In response to your experience on the virtual facility tour, and after reviewing the websites, answer the following questions on how this process impacts the environment. You may chose to answer these questions using either the Back River or Patapsco Wastewater Treatment Plant. Please cite your sources using the appropriate citation for each questions. The works cited should be at the end.

1. Which plant did you chose to study? What areas and how many customers does this facility serve?

2. How does this facility compare with others in the Greater Baltimore area?

3. What happens to flow during and following a heavy rain?

4. What effect, if any, does this have on the quality and quantity of effluent discharged from this facility?

5. What is the highest level of treatment that the wastewater undergoes at this facility?

6. While the Baltimore Plants have adopted new technology over the last few years, what other technology or processes could they implement to better clean the effluent? Describe at least one additional process not currently being used at the plant you chose. You will need to use additional sources – be sure to cite them!

7. By what processes are harmful pathogens removed from the plant’s effluent?

a. What is the impact on the waterbody into which the water is discharged?

b. How has the disinfection process changed in the past 20 years?

8. How does the water leaving the plant (the final effluent) compare to the water entering the plant? Is it ready for drinking?

9. What regulations govern the operation of wastewater treatment plants?

a. What does the facility do to ensure that these regulations are met?

10. What role is played by environmental scientists in the operation of this facility?

11. How can products of the treatment process serve as resources?

Revised Fall 2019 4.2 - 3