GAH! I've been trying to log in for a while to write this, had issues with my account. I would love to give you some help. I have taken the FE environmental twice, failed the first time, currently awaiting results on the next one. Even if I don't pass the second one, I have learned a lot about studying from taking it twice. First time I took it I studying for 2 months more of less. This second time it was closer to 4.5. I went over a lot of concepts and watching a lot of youtube videos explaining things I wasn't sure on the first time. This is ok if you have lots of time to study and have forgotten major topics. Best thing you can do now is: The enviro specific review from PPI (these were a great help for learning how to solve and use the reference manual) It is really difficult to find study material for our exam (I feel your pain). Go over the problems without looking at the answer as much as you can, because it will get your brain to think about how to solve problems with what you know so far. The environmental specific review from PPI is very expensive for how small it is, but it was worth it for how spot on the topics were (didn't cover groundwater well or qualitative problems, just practice problems and a brief overview) Finding the right topics in the PPI overall review book helped as well, but weren't in depth.
The online NCEES exam was a great help, but was 1$ a problem! The exam problems were actually a bit harder than the review in this case for me. It wasn't that the topic was harder, it still looked similar, but presented it in a different way. For example (without going into too much depth), drawdown for confined and unconfined aquifers was covered in the review, but in the exam it applied it to using Darcy's equation and conductivity in a way I hadn't thought of before or had never encountered.
Oh yeah, I should have prefaced this with the fact that I am a biochem major, not an engineer, so you should have a big advantage over me. I didn't have the training to fall back on and had to self-teach for mostly every thing, which I am totally not bragging about because I wish I had chosen engineering! So if you have a degree in engineering and learned all these things from teachers and have school books about them, be confident in your abilities! Take your daily schedule seriously and set apart multiple hours a day for studying and reviewing with lots of breaks. Stick with your strong points, and focus on the second half of the topics, which are worth the most points. Once you feel confident in those areas, bo back and work at the smaller things like thermo and math and econ. Again, this is my opinion, but I have heard similar things voiced elsewhere.
PRACTICE PROBLEMS will be the best thing for you. The FEPREP website would have been a lot more beneficial to me if I had used it for longer, but I work a full time job with a baby on the way, so it was difficult. I also purchased a book from Pearson, which said it was made specifically for the environmental CBT. I found it helpful for large concepts, especially the less quantitative subjects such as wastewater and landfilling and the like. The practice problems in it were severely lacking and often employed formulas and concepts not found in the review and often very convoluted with a lot of errata.
I focused a lot of fluid mechanics since a lot of the other topics use aspects of fluid mechanics (ie hydraulic head in wastewater plants, stokes law for aquifers)
Best of luck to you! If there are any other questions I can answer for you just let me know, hopefully my account will not act up again (thanks Mike for the help)
Pat