At the risk of bringing on the enviro-rain…may I suggest that you landfill your plastic waste (if there is no recycling process for it , ref semi-return to petro above).
Unlike yard waste, paper and the like, plastic waste does not decompose into a large volume of gas. It’s much better landfill a stable, long lasting waste. When you eventually build on top of the closed fill, you don’t want all that decomposition going on under your foundation.
People shudder at the horror of landfills. In truth, if done correctly, they are a low impact, stable, inexpensive destination for solid trash.
OK… bring it on.