PROBLEM TO BE SOLVED: To provide methods of utilizing residues after methane fermentation of organic waste which can aim at reusing a waste product by effectively utilizing residues such as methane fermentation sludge after methane fermentation of organic waste having a trouble of waste disposal, and, simultaneously, which can utilize as a novel nutrient source capable of promoting growth of aquatic organisms by quickly solving poor nutrient conditions of a water area.SOLUTION: A utilization method of residues after methane fermentation of organic waste of the present invention is a utilization method using residues obtained after methane fermentation of organic waste by a methane fermentation facility as a nutrient resource by supplying into a water area, the residue obtained after methane fermentation is at least one residue selected from the group consisting of a digestion liquid, a dehydrated filtrate obtained by dehydrating a digestive juice in a dehydrating facility, a dehydrated sludge of a digestive liquid, and a nitrification tank treatment liquid obtained by introducing a dehydrated filtrate into a biological nitrification facility and nitrifying ammonia in a dehydrated filtrate, a membrane separation liquid obtained by membrane separation of a methane fermentation sludge by a membrane separation facility, a nitrification tank treatment liquid obtained by introducing a membrane separation liquid into a biological nitrification facility and nitrifying ammonia in the membrane separation liquid.SELECTED DRAWING: Figure 1【課題】 廃棄処理に困っている有機性廃棄物をメタン発酵させた後のメタン発酵汚泥等の残渣物を有効利用して廃棄物の再利用を図るとともに、水域の貧栄養状態を迅速に解消して水生生物の育成が促進できる新たな栄養源として利用することができる、有機性廃棄物のメタン発酵後残渣物の利用方法を提供する。【解決手段】 本発明の有機性廃棄物のメタン発酵後残渣物の利用方法は、有機性廃棄物をメタン発酵設備でメタン発酵させた後に得られた残渣物を、水域に投与して生物の栄養源として使用する利用方法であり、メタン発酵させた後に得られた残渣物は、消化液、消化液を脱水設備で脱水した脱水ろ液、消化液の脱水汚泥、脱水ろ液を生物学的硝化設備に導入して脱水ろ液中のアンモニアを硝化した硝化槽処理液、メタン発酵汚泥を膜分離設備で膜分離した膜分離液、膜分離液を生物学的硝化設備に導入して膜分離液中のアンモニアを硝化した硝化槽処理液からなる群より選ばれる少なくとも１種の残渣物である。【選択図】 図１
