巻頭言巻 頭 言
私が廃棄物リサイクルとして生ごみのコンポスト化に注目したのは、今から 19 年前の 2000 年になります。それまでは、環境計量士の業務を通じて、水質、大気、土壌及び産業廃棄物などの環境に係わるデータを提供することに没頭していました。その一方で、地域の環境活動にも参加していたところ、有機農業に興味を強く持つようになりました。そして、地域の任意団体として「若松循環型農業システム研究会」が立ち上がり、ひょんなことからその会⾧に就任することになり、その研究会活動を通じて、生ごみコンポストに出会いました。どうして生ごみコンポストに取り組んだかというと、そのほとんどが焼却処理されておりリサイクルされていなかったからです。
私は研究会の活動だけでなく、様々な機会を通じてコンポスト技術の習得に励み、2004 年に国際技術協力として取り組んだ「インドネシア共和国スラバヤ市の有機廃棄物の資源化・減量化プロジェクト」を通じて、現地で「高倉式コンポスト」を確立しました。
高倉式コンポストはコンポストの基本理論に沿って展開しており、適正化が図り易く現地への導入が容易な技術として、主に JICA のスキームを通じてアジア及び中南米を中心に様々な国々で活用していただいています。

1

巻頭言

KITA 特設コーナーではシリーズとして下記の内容で掲載されます。
第 1 章 はじめに

私たちと廃棄物問題

第 2 章 廃棄物管理改善を目指して
第 3 章 コンポスト化技術 基本的な考え方
第 4 章 コンポスト化技術の基本理論 重要項目
第 5 章 コンポスト化技術の基本理論 注意すべき項目
第 6 章 コンポスト化技術の基本理論から実践へ
第 7 章 コンポストの効果的な使用方法

執筆に当たってはコンポストの入門と位置づけ、私が JICA 研修の講義で実施している内容を中心に、コンポストについて未経験の方にも親しみが持てるように、工夫してまとめました。コンポストについては様々な考え方があります。当シリーズを読みコンポストに興味を持たれた方は、他のコンポストに関係する図書、専門書及び論文などを見ていただき、更に知識を深めていただければ幸いです。
そして、知識の取得に留まること無く、行動化へと一歩踏み出しましょう。
2019 年 7 月 7 日髙倉 弘二
工学博士 技術士(衛生工学・環境)
2目次

第1章 目次1. はじめに ······························································································································ 1
1.1 私たちと廃棄物問題 ········································································································· 1
1.1.1 日本の循環型社会の歴史 ······························································································· 3(1) 1900 年以前の循環型社会 ································································································ 3(2) 1900 年代(20 世紀)の循環型社会の破壊・崩壊と修復 ····················································· 31.1.2 日本の循環型社会の今後 ······························································································· 4(1) 21 世紀が目指す循環型社会····························································································· 4(2) 江戸時代の感性を現代にアレンジ ·················································································· 5
1.2 開発途上国の廃棄物の現状と廃棄物問題·········································································· 6
1.3 廃棄物管理改善と生ごみのリサイクル ············································································· 91.3.1 廃棄物を埋め立て処分場に依存する弊害 ····································································· 91.3.2 生ごみのコンポスト化と廃棄物削減 ··········································································· 101.3.3 スラバヤ市の廃棄物管理改善事例 ·············································································· 111.4 生ごみコンポスト化と SDGs ·························································································· 13
1.4.1 SDGs とは ·················································································································· 13
参考資料 ····························································································································· 16

第2章 目次

2. 廃棄物管理改善を目指して ································································································· 1
2.1 廃棄物管理が地域で定着するための 5 つのポイント ························································ 12.2 スラバヤ市の廃棄物管理改善への取り組み ······································································ 22.2.1 行政施策として、「緑豊かな環境・衛生に配慮した都市づくりを目指す」ことを宣言 22.2.2 Green Clean Campaign を実施する上で不十分であった技術の充足 ······························ 52.2.3 コンポストセンターの整備・拡充 ················································································ 92.2.4 資源ごみ分別回収センター及び大規模コンポストセンターの整備・運営 ··················· 102.3 生ごみコンポスト化に取り組む目的 ············································································· 122.3.1 コンポストの使用 ········································································································ 122.3.2 コンポスト化のコスト負担 ························································································ 122.3.3 適正技術を導く方法 ··································································································· 13
参考資料 ······························································································································ 16

1

第3章 目
3. コンポスト化技術-基本的な考え方

次····················································································· 1

3.1 コンポスト化の歴史 1 ·········································································································
3.2 コンポスト化の基本的な考え方 ························································································ 13.2.1 コンポスト化の過程は「発酵」 ···················································································· 23.3 コンポスト化の基本的な流れ ··························································································· 33.3.1 前処理工程 ··················································································································· 3(1) 異物の除去 ···················································································································· 3(2) 機械式による異物除去の限界混合廃棄物の受け入れ ····················································· 43.3.2 発酵工程 ······················································································································ 8(1) リターンコンポストの考え方 ························································································ 93.3.3 製品化工程 ················································································································· 10
参考資料 ····························································································································· 112

第4章 目
4. コンポスト化技術の基本理論-重要項目

次············································································ 14.1 微生物について ················································································································ 14.1.1 コンポスト化は大きく 3 段階に分かれる ···································································· 1(1) 第 1 段階： ··················································································································· 2(2) 第 2 段階： ··················································································································· 3(3) 第 3 段階： ··················································································································· 44.1.2 コンポスト化には多様な微生物が関係 ········································································· 54.1.3 コンポスト化には土着菌 ······························································································ 54.1.4 発酵食品を入手できないとき ······················································································· 5(1) 森の腐葉土 ···················································································································· 5(2) 空気中に浮遊する乳酸菌と酵母菌 ················································································· 64.2 酸素について ···················································································································· 74.2.1 悪臭が発生するリスクを減らすことができる ······························································ 74.2.2 コンポスト化の期間を短縮することができる ······························································ 84.2.3 衛生的なコンポストを製造することができる ······························································ 94.2.4 温度が高くなることで、さらにコンポスト化の期間を短縮することができる ············ 104.2.5 温度が高くなることで、無排水化を図ることができる ·············································· 12(1) 細胞が持っている大量の水＋微生物が有機物を利用すると水が生成 ·························· 13(2) 生ごみの水分は脱水しない方が良い ··········································································· 144.3 好気発酵の注意点 ··········································································································· 144.3.1 空気の供給量には適量がある ····················································································· 144.3.2 水分について ············································································································· 154.3.3 コンポスト化をスムーズに進めるための水分チェック ·············································· 17(1) 水分チェックの方法 ···································································································· 17(2) 水分チェックの注意点 ································································································ 18
参考資料 ····························································································································· 193

第5章 目
5 コンポスト化技術の基本理論-注意すべき項目

次···································································· 15.1 pH ····································································································································· 15.1.1 リターンコンポストの活用 ·························································································· 15.1.2 アルカリ剤の添加 ········································································································ 25.2 C/N(炭素・窒素比) ········································································································ 25.2.1 コンポスト化時の C/N ································································································ 25.2.2 コンポスト製品の C/N ································································································ 45.3 通気(エアレーション) ······································································································ 55.3.1 送風機によるエアレーション(強制通気) ······································································ 55.3.2 切り返し(撹拌) ············································································································ 75.4 原料の形状 ······················································································································· 7
5.5 空隙率と容積重(比重) ······································································································ 85.6 塩分の影響 ······················································································································· 85.7 油分の影響 ····················································································································· 105.8 コンポスト化の発酵工程 ································································································· 105.8.1 「一次発酵・二次発酵」 ···························································································· 10(1) 一次発酵：, (2) 二次発酵： ····················································································· 115.8.2「第一段階・第二段階・第三段階」 ············································································ 11(1) 第一段階：, (2) 第二段階：, (3) 第三段階： ························································· 115.8.3「未熟コンポスト・中熟コンポスト・完熟コンポスト」 ············································· 11(1) 未熟コンポスト：, (2) 中熟コンポスト：, (3) 完熟コンポスト：·························· 125.8.4 コンポスト化終了の判断 ···························································································· 13
参考資料···························································································································· 144第6章 目次

6 コンポスト化技術の基本理論から実践へ ············································································· 1
6.1 微生物を培養して発酵床(シードコンポスト)をつくる ····················································· 1
6.1.1 発酵液をつくる ··········································································································· 1(1) 砂糖水による培養 ··········································································································· 1(2) 食塩水による培養 ··········································································································· 2
6.1.2 発酵床をつくる ············································································································ 3(1) 床材をつくる ·················································································································· 3(2) 発酵液を混ぜる ·············································································································· 5(3) 床材と発酵液を混ぜる···································································································· 6(4) 発酵床の完成 ·················································································································· 66.1.3 家庭用コンポスト化容器を使用した小規模培養 ··························································· 7(1) 砂糖水による培養 ··········································································································· 7(2) 食塩水による培養 ··········································································································· 7(3) 発酵床をつくる ·············································································································· 8(4) 砂糖水及び食塩水の培養を省略する方法 ········································································ 96.1.4 大規模コンポストセンター時の大量培養 ··································································· 10(1) 砂糖水による培養, (2) 食塩水による培養, (3) 発酵床をつくる ······························ 106.2 家庭での取り組み～家庭用コンポスト～ ········································································ 136.2.1 ステップ 1：下準備 ··································································································· 13(1) 通気性がある容器を準備する ······················································································ 13(2) 容器の大きさ ·············································································································· 13(3) 容器の内張り ·············································································································· 14(4) 容器の内張りの例 ······································································································· 15(5) ミズアブ等の虫対策 ···································································································· 18(6) コンポスト化容器の置き場所 ······················································································ 196.2.2 ステップ 2：生ごみの投入 ························································································· 1956.2.3 ステップ 3：コンポストの完成 ·················································································· 206.3 コンポストセンターでの取り組み ·················································································· 216.3.1 コンポストセンターで取り組むメリット・デメリット ·············································· 216.3.2 コンポストセンターの基本条件 ················································································· 23(1) コンポストセンター建設時に考慮する点 ···································································· 23(2) 道具・機材類 ·············································································································· 23
6.4 小規模コンポストセンター ····························································································· 25
6.4.1 ステップ 1：準備 ······································································································· 25
6.4.3 小規模コンポストセンターの例 ················································································· 27
6.4.4 小規模コンポストセンターの取り組み例：ブータン ·················································· 27
6.4.5 小規模コンポストセンターの取り組み例：フィリピン ·············································· 30
6.5 中規模コンポストセンター ····························································································· 32
6.5.1 ステップ 1：準備 (フィリピンを例として) ······························································ 32
6.5.2 コンポスト化の手順 (フィリピンを例として) ························································· 336.5.3 中規模コンポストセンターの取り組み例：ボリビア ·················································· 366.5.4 中規模コンポストセンターの取り組み例：エクアドル ················································ 396.6 大規模コンポストセンター ····························································································· 446.6.1 ステップ 1：準備 ······································································································· 44
6.6.2 大規模コンポストセンターの取り組み例：ベトナム··················································· 45
参考資料 ······························································································································ 546