Integrated waste treatment and fertilizer and feed supplement production methods to be implemented at organic waste source sites, at remote treatment sites, or partially at the organic waste source site and at a remote location, whether in small or large scale operations. The methods are suitable for retrofitting existing organic waste sources and for treating the organic waste generated by a single source or by a plurality of sources. These methods provide: reduction or elimination of emissions of acrid and greenhouse gases; effluents that meet discharge standards and that can be used in wetland and irrigation projects; organic based, granular, slow release NPK fertilizer of standard composition and size that can be supplemented with micronutrients and soil amendment materials and whose composition can be adjusted to meet demands and needs of specific markets; methane-rich biogas recovery for its subsequent use for heating, for power generation or for catalytic and synthetic processes, and feed supplement including feed supplement for cattle. The methods comprise steps for thoroughly separating suspended and dissolved materials, preventing gas emissions and capturing gases, and minimizing waste disposal. Fertilizer base may be produced by mixing waste with at least one of a phosphate precipitating agent, a base, a flocculant, and optionally with an ammonia retaining agent and a densifier, subsequently separating and drying the precipitate. Pathogen-free, odor-free and dust-free fertilizer may be obtained by temperature controlled incineration or combustion.