Option 1 is correct because pyrolysis does indeed convert solid waste into solid, liquid, and gas products. The resultant liquid and gas can be used to produce energy.

Option 2 is incorrect because pyrolysis actually occurs at a temperature above 430°C, but it does not necessarily need to be at atmospheric pressure. Pyrolysis can be carried out under varying pressure conditions depending on the specific process and equipment used.

Option 3 is also incorrect because pyrolysis does not occur under high pressure. It typically occurs at atmospheric pressure or slightly above.

Option 4 is correct because pyrolysis is a thermochemical decomposition process that breaks down organic waste by heating it in the absence of oxygen. This results in the production of solid char, liquid bio-oils, and gases.