Process of conversion of solid waste into workable material with predetermined characteristics and/or into fertilizers or soil improving agents

A process for composting waste material including the following steps:

• supplying raw waste material;
• grinding said supplied waste material into particles;
• extracting said ground particles within a predetermined size range;
• extracting iron containing particles from said particles within said predetermined size range;
• digesting said particles within said predetermined size range having said iron particles extracted therefrom;
• said step of digesting includes the steps of:
• exposing said digesting particles to oxygen by raking said digesting particles;
• controlling said exposure by controlling the rate of raking;
• continually controlling the pH value of said digesting particles by selectively adding a water diluted nitrogen-phosphorous buffer solution having a pH value within the range of 6.2 to 6.8% in order to produce a digested material having a stable pH value of approximately 7.3;
• continually controlling the moisture content of said digesting particles according to a linear value of moisture content with respect to time by selectively adding relatively hot water to produce a digested material having a moisture content in the range of from 10-30% by weight;
• continually controlling the temperature of said digesting particles within a predetermined temperature range;
• advancing said digesting particles over a series of stacked horizontal decks by said step of raking and performing said steps of continually controlling the pH value and continually controlling the moisture content in response to steps of monitoring the pH value and moisture content at a plurality of predetermined locations along said horizontal decks.