Ersättning av järnsalter med magnesiumföreningar vid kommunala ...

Innehållsförteckning
1. Inledning .......................................................................................................................................... 1
1.1. Syfte ........................................................................................................................................ 1
1.2. Rapportens disposition ............................................................................................................ 1
1.3. Begränsningar .......................................................................................................................... 2
2. Bakgrund ......................................................................................................................................... 3
2.1. Lagar och föreskrifter .............................................................................................................. 3
2.2. Reningsverk idag ..................................................................................................................... 4
2.2.1. Mekanisk rening .............................................................................................................. 5
2.2.2. Biologisk rening .............................................................................................................. 5
2.2.3. Kemisk rening ................................................................................................................. 7
2.2.4. Slamhantering .................................................................................................................. 9
3. Magnesium i avloppsvatten ........................................................................................................... 11
3.1. Magnesium som flockningsmedel ......................................................................................... 11
3.2. pH-justering med Mg(OH)2 ................................................................................................... 11
3.3. Magnesium i biologisk rening ............................................................................................... 12
3.4. Miljöpåverkan ....................................................................................................................... 12
4. Struvit (MAP) ................................................................................................................................ 13
4.1. Struvitbildning ....................................................................................................................... 13
4.1.1. Användningsområden .................................................................................................... 14
4.1.2. Magnesiumkällor ........................................................................................................... 15
4.2. Upplösning av struvit ............................................................................................................ 15
4.2.1. Upplösning med nitrifikationsbakterier ......................................................................... 16
4.2.2. Upplösning med anammoxbakterier .............................................................................. 17
4.2.3. Tidigare studier om bakteriell upplösning ..................................................................... 18
4.3. Processförslag ........................................................................................................................ 18
5. Material och metod ........................................................................................................................ 21
5.1. Fällningsförsök ...................................................................................................................... 21
5.1.1. Material ......................................................................................................................... 22
5.1.2. Analyser ......................................................................................................................... 22
5.1.3. Experimentbeskrivning.................................................................................................. 23
5.2. Upplösningsförsök ................................................................................................................. 23
5.2.1. Material ......................................................................................................................... 25
5.2.2. Analyser ......................................................................................................................... 25