I reread your question, and I think I missed the mark the first time in answering about just the research portion. I don't think I ever dealt directly with that. I always let that be the ONE thing the parents were responsible for helping with in our group . But here's an idea :)  Since google is our friends, have you considered getting them to think of keywords to research? Research starts first and foremost with considering what you are looking for.  Try getting in a place where several laptops or computers are available and then researching topic words in small groups.  Add the word "solution" to your google topic.  If they have no idea where to begin, are field trips a possibility- the composting plant, a recycling plant, a waste management plant- maybe they have trouble wiht different ways things go into the waste water?   Virtual field trips are also possible. Get short videos on trash- or get the kids to find a youtube video on trash or recycling or plastics or biodegradable products to share with the group.