This teacher guide is part of the Environmental Inquiry (EI) curriculum series developed at Cornell University to enable high school students to conduct authentic environmental science research. The goals of EI are for students to: (1) develop research skills; (2) use their newly acquired skills to conduct research projects of their own design, focusing on topics relevant to their local communities; (3) participate in communities of peer student scientists; and (4) enhance their understanding of scientific content and process. EI students experience the research process through which scientific understandings are formed and continually revised. Topics covered in this series include: (1) "Natural Forces of Decay and Renewal"; (2) "Harnessing Natural Decay"; (3) "Bioremediation: Using Microbes to Clean Up Contaminated Sites"; (4) "Identifying Decomposers"; (5) "Chemical Effects of Biodegration"; (6) "Composting and Landfilling"; (7) "Bioremediation"; (8) "Protocol Planning and Review Forms"; (9) "Ideas for Biodegradation Research"; (10) "Forms for Interactive Research"; (11) "Wastewater Treatment Design Challenge"; and (12) "Forms for Wastewater Treatment Design Challenge". (MVL)