In this lesson, students expand their understanding of solid waste management to include the idea of 3RC (reduce, reuse, recycle and compost). They will look at the effects of packaging decisions (reducing) and learn about engineering advancements in packaging materials and solid waste management. Also, they will observe biodegradation in a model landfill (composting).

By studying key processes in the carbon cycle, such as photosynthesis, composting and anaerobic digestion, students learn how nature and engineers "biorecycle" carbon. Students are exposed to examples of how microbes play many roles in various systems to recycle organic materials and also learn how the carbon cycle can be used to make or release energy.

In a multi-week experiment, students monitor the core temperatures of two compost piles, one control and one tended, to see how air and water affect microbial activity. They daily aerate and wet the "treated" pile and collect 4-6 weeks' worth of daily temperature readings. Once the experiment is concluded, students plot and analyze their data to compare the behavior of the two piles. They find that the treated pile becomes hotter, an indication that more microbes are active and releasing heat. Through this activity, students see that microbes play a role in composting and how composting can be used as a carbon management process.

Students explore the concept of biodegradability by building and observing model landfills to test the decomposition of samples of everyday garbage items. They collect and record experiment observations over five days, seeing for themselves what happens to trash when it is thrown "away" in a landfill environment. This shows them the difference between biodegradable and non-biodegradable and serves to introduce them to the idea of composting. Students also learn about the role of engineering in solid waste management.

Students design and build model landfills using materials similar to those used by engineers for full-scale landfills. Their completed small-size landfills are "rained" on and subjected to other erosion processes. The goal is to create landfills that hold the most garbage, minimize the cost to build and keep trash and contaminated water inside the landfill to prevent it from causing environmental damage. Teams create designs within given budgets, test the landfills' performance, and graph and compare designs for capacity, cost and performance.

In a multi-week experiment, student teams gather biogas data from the mini-anaerobic digesters that they build to break down different types of food waste with microbes. Using plastic soda bottles for the mini-anaerobic digesters and gas measurement devices, they compare methane gas production from decomposing hot dogs, diced vs. whole. They monitor and measure the gas production, then graph and analyze the collected data. Students learn how anaerobic digestion can be used to biorecycle waste (food, poop or yard waste) into valuable resources (nutrients, biogas, energy).

How does infrastructure meet our needs? What happens when we are cut off from that supporting infrastructure? As a class, students brainstorm, identify and explore the pathways where their food, water and energy originate, and where wastewater and solid waste go. After creating a diagram that maps a neighborhood's inputs and waste outputs, closed and open system concepts are introduced by imagining the neighborhood enclosed in a giant dome, cut off from its infrastructure systems. Students consider the implications and the importance of sustainable resource and waste management. They learn that resources are interdependent and that recycling wastes into resources is key to sustain a closed system.

Student teams find solutions to hypothetical challenge scenarios that require them to sustainably manage both resources and wastes. They begin by creating a card representing themselves and the resources (inputs) they need and wastes (outputs) they produce. Then they incorporate additional cards for food and energy components and associated necessary resources and waste products. They draw connections between outputs that provide inputs for other needs, and explore the problem of using linear solutions in resource-limited environments. Then students incorporate cards based on biorecycling technologies, such as algae photobioreactors and anaerobic digesters in order to make circular connections. Finally, the student teams present their complete biorecycling engineering solutions to their scenarios in poster format by connecting outputs to inputs, and showing the cycles of how wastes become resources.

Students construct model landfill liners using tape and strips of plastic, within resource constraints. The challenge is to construct a bag that is able to hold a cup of water without leaking. This represents similar challenges that environmental engineers face when piecing together liners for real landfills that are acres and acres in size.

Students explore the concept of "reducing" solid waste and how it relates to product packaging and engineering advancements in packaging materials. They read about and evaluate the highly publicized packaging decisions of two major U.S. corporations. Then they evaluate different ways to package items in order to minimize the environmental impact, while considering issues such as cost, availability, product attractiveness, etc. In addition, students explore "hydropulping" and consider its use as a recycling process.

Waste disposal has been an ongoing problem since medieval times. Environmental engineers are employed to develop technologies to dispose of the enormous amount of trash produced in the United States. In this lesson, students will learn about the three methods of waste disposal in use by modern communities. They will also investigate how engineers design sanitary landfills to prevent leachate from polluting the underlining groundwater.

In this lesson, students will extend their knowledge of matter and energy cycles in an organism to engineering life cycle assessment of a product. Students will learn about product life cycle assessment and the flow of energy through the cycle, comparing it to the flow of nutrients and energy in the life cycle of an organism.

Students are introduced to the growing worldwide environmental problems that stem from plastic waste. What they learn about microplastics and the typical components of the U.S. water treatment process prepares them to conduct three engaging associated activities. During the lesson, students become more aware of the pervasiveness and value of plastic as well as the downstream pollution and health dangers. They learn how plastic materials don’t go away, but become microplastic pollution that accumulates in water resources as well as human and other animal bodies. They examine their own plastic use, focusing on what they discard daily, and think about better ways to produce or package those items to eliminate or reduce their likelihood of ending up as microplastic pollution. A concluding writing assignment reveals their depth of comprehension. The lesson is enhanced by arranging for a local water treatment plant representative to visit the class for Qs and As. In three associated activities, students design/test microplastic particle filtering methods for commercial products, create mini wastewater treatment plant working models that remove waste and reclaim resources from simulated wastewater, and design experiments to identify the impact of microplastics on micro-invertebrates.

Students investigate the life cycles of engineered products and how they impact the environment. They use a basic life cycle assessment method that assigns fictional numerical values for different steps in the life cycle. Then they use their analyses to compare the impacts of their products to other products, and suggest ways to reduce environmental impact based on their analyses.

Over the course of three sessions, students act as agricultural engineers and learn about the sustainable pest control technique known as soil biosolarization in which organic waste is used to help eliminate pests during soil solarization instead of using toxic compounds like pesticides and fumigants. Student teams prepare seed starter pots using a source of microorganisms (soil or compost) and “organic waste” (such as oatmeal, a source of carbon for the microorganisms). They plant seeds (representing weed seeds) in the pots, add water and cover them with plastic wrap. At experiment end, students count the weed seedlings and assess the efficacy of the soil biosolarization technique in inactivating the weed seeds. An experiment-guiding handout and pre/post quizzes are provided.

Students collect, categorize, weigh and analyze classroom solid waste. The class collects waste for a week and then student groups spend a day sorting and analyzing the garbage with respect to recyclable and non-recyclable items. They discuss ways that engineers have helped to reduce the accumulation of solid waste.