To get municipalities to replace waste treatment with Anaerobic digesters. Also called Methane digesters, they take solid waste (sewage) and compost it under anaerobic conditions. This creates methane, which is harnessed as a fuel source, and safe fertilizer. Most biological contaminants are killed by the heat of the process, a little further treatment is all that's required. It also prevents a lot of material from being dumped into the environment, leading to cleaner water. This is a scalable technology, with home scale versions all the way up to city treatment plants. It's fairly well proven, it isn't a new technology. It's just underused. Simple version can be constructed out of a few jugs and some tubing, commercial versions are already available.
We need people who can build, maintain, repair and/or sell the methane digesters. Many existing models are on the market.
We need people in municipal government, city planners and councilors who will push to get these built in their cities.
We need people to lobby their local government, and to educate their neighbors and mobilize them.