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Worksheet Grade 8 English Language Arts

Foxglen's Wastewater Biofilter: A Grade 8 Process Worksheet

A grade 8 worksheet where students trace a fictional garden's wastewater biofilter stages, define vocabulary in context, and write a short informative paragraph.

Objectives

  1. Students will sequence the stages of a wastewater biofilter using a process description.
  2. Students will cite specific evidence explaining how bacteria and plant roots remove dissolved waste.
  3. Students will write a short informative paragraph that explains the biofilter's process using precise vocabulary.

Vocabulary

Key words: biofilter, environmental biotechnology, nutrients, bacteria, settling

Teacher overview

Foxglen Community Garden (a fictional site used for this worksheet) built a small biofilter, sometimes called a constructed wetland, to treat wastewater from a rinse station near its toolshed instead of letting it run into a storm drain untreated. This worksheet gives students a process description of how the biofilter works, using real biological and physical principles such as plant roots, gravel, and naturally occurring bacteria, and asks them to trace the sequence, define technical vocabulary from context, and then write a short informative explanation of their own. A misconception worth addressing directly: students often picture a "filter" as something that only physically strains out solid particles, when a biofilter's bacteria and plant roots also break down and absorb dissolved nutrients, not just solids.

Foxglen's Wastewater Biofilter: A Grade 8 Process Worksheet — Grade 8 English Language Arts
Name: ____________________________ Date: ______________

Student Worksheet

How Foxglen Community Garden's Biofilter Works

Foxglen Community Garden is a fictional site used for this worksheet. It sends wastewater from its outdoor rinse station through a shallow gravel bed. The bed is planted with cattails and other wetland plants. That way, the water never drains untreated into the street. This small-scale system relies on environmental biotechnology, the use of living organisms to solve environmental problems.

The process happens in three stages. First, the wastewater flows into a settling chamber. There, heavier solids sink to the bottom before the water moves on. Second, the water passes slowly through a bed of gravel planted with cattails and bulrushes. The gravel physically traps smaller particles. At the same time, bacteria living on the gravel and plant roots break down dissolved organic waste. Third, the plant roots absorb nitrogen and phosphorus. These are the two nutrients most responsible for algae blooms downstream. The roots pull those nutrients out of the water and into new plant growth. By the time the water reaches the outlet, it is clear enough to soak safely into a nearby planting bed.

Garden volunteers check the system each month. They look for standing water at the inlet, a sign the gravel bed may be clogging. They also check plant health at the outlet, a sign the system is still removing nutrients.

Now answer the following questions.

  1. List, in order, the three stages wastewater passes through in Foxglen's biofilter.
  2. What happens to heavier solids during the first stage?
  3. Find the sentence that explains what happens to dissolved organic waste in the gravel bed. Write that sentence or a close paraphrase.
  4. Define "environmental biotechnology" in your own words, using the passage's description as your starting point.
  5. Which two nutrients do the plant roots absorb, and why does the passage identify those two as important to remove?
  6. Cite the specific detail in the passage that explains why volunteers check for standing water at the inlet.
  7. Explain the difference between what the gravel does and what the plant roots do in the biofilter. Use both terms in your answer.
  8. Why might a "filter" that only trapped solid particles fail to solve Foxglen's water quality problem completely, based on the passage?
  9. Write a short informative paragraph, three to four sentences, that explains how Foxglen's biofilter cleans wastewater. Use the term "biofilter" and at least one of "nutrients," "bacteria," or "gravel" precisely in your paragraph.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: Settling, in which solids sink out, then the gravel and plant bed, which traps and breaks down waste, then nutrient uptake by plant roots. Students may combine stages two and three since the passage describes them together, as long as the order is correct.
  2. Answer: Heavier solids sink to the bottom of the settling chamber before the water continues to the gravel bed.
  3. Answer: "At the same time, bacteria living on the gravel and plant roots break down dissolved organic waste." Close paraphrases that keep the idea of bacteria breaking down dissolved waste are acceptable.
  4. Answer: Environmental biotechnology is the use of living organisms, such as plants and bacteria, to solve environmental problems, as the passage describes with Foxglen's gravel-and-plant system treating wastewater.
  5. Answer: Nitrogen and phosphorus. The passage identifies them because they are the two nutrients most responsible for algae blooms downstream if they are not removed.
  6. Answer: The passage states that standing water at the inlet is a sign the gravel bed may be clogging, which is why volunteers watch for it during their monthly checks.
  7. Answer: The gravel physically traps smaller particles as water passes through it, while the plant roots absorb dissolved nutrients like nitrogen and phosphorus, taking them out of the water rather than trapping solids.
  8. Answer: Answers will vary but should note that a filter which only trapped solid particles would leave dissolved nutrients like nitrogen and phosphorus in the water, since those nutrients are dissolved rather than solid and, in this system, are removed by biological processes such as plant uptake rather than by physical trapping.
  9. Answer: Paragraphs will vary. A strong paragraph correctly sequences the biofilter's stages, uses "biofilter" to name the whole system, and uses at least one of "nutrients," "bacteria," or "gravel" precisely to describe a specific step in the process, rather than as a vague reference.

Differentiation

Support (below grade level)

Provide a simple three-box diagram of the settling chamber, gravel bed, and outlet, with one blank line under each box for students to fill in what happens there, before they attempt the writing task in item 9.

Extension (above grade level)

Ask students to infer (using only the passage provided, not outside sources) what might happen to Foxglen's biofilter if volunteers stopped checking it monthly, and to write two additional sentences predicting the consequence using vocabulary from the passage.

ELL supports

Pre-teach "biofilter," "settling," "nutrients," and "absorb" with a simple diagram labeled in English and, where possible, students' home languages. Allow items 1, 2, and 5 to be answered with short phrases or a completed diagram instead of full sentences.