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Utvärdering av matavfallskvarnssystem i kv. Fullriggaren, Västra Hamnen i Malmö

Magnusson, Nicolina LU (2015) VVA820 20151
Chemical Engineering
Abstract
To collect, treat and use food waste is desirable in society in order to recycle and efficiently use all resources. One stage of one of the Swedish environmental goals is to collect and treat 50 % of the food waste biologically in year 2018. A useful product from this treatment is biogas, which can be used for fueling vehicles, heating and producing electricity. Biogas could be produced from food waste by anaerobic digestion.

Fullriggaren is a neighborhood consisting of 600 apartments in the Western Harbor in Malmö. Food waste disposers were already installed during the construction in 2012. The food waste disposers are installed directly in the kitchens sinks and all water from the kitchen is lead and pumped into the tank. There are... (More)
To collect, treat and use food waste is desirable in society in order to recycle and efficiently use all resources. One stage of one of the Swedish environmental goals is to collect and treat 50 % of the food waste biologically in year 2018. A useful product from this treatment is biogas, which can be used for fueling vehicles, heating and producing electricity. Biogas could be produced from food waste by anaerobic digestion.

Fullriggaren is a neighborhood consisting of 600 apartments in the Western Harbor in Malmö. Food waste disposers were already installed during the construction in 2012. The food waste disposers are installed directly in the kitchens sinks and all water from the kitchen is lead and pumped into the tank. There are two tanks and the area is split into two systems; east and west.

This report is a continual evaluation of the neighborhood Fullriggaren based on an earlier study. The aim was to investigate if there is a difference in methane potential in the two systems. The existing mass balance needed to be improved with new background levels. Therefore a small literature study regarding nutrients from kitchen sinks was performed. An investigation about the avoidable food waste in kitchen sinks included an estimate of the distribution of every product in each waste category. This was based on the result from a report where the amount of avoidable food waste was poured into the sink and then measured in randomly selected households. The purpose with this study was to obtain a reliable background value to use in the mass balance.

The methane potential was measured in three bio methane potential (BMP) tests. The food waste from the western system generated more methane than the food waste from the eastern system, 593 respectively 543 Nml CH4/g VS. During the three performed BMP-tests, differences between the eastern and the western tank were observed. Compared to earlier studies, the result shows the opposite with highest methane production in the eastern tank. The conclusion is that the amount methane gas varies in different time occasions and seems to depend on the composition of the food waste during each sampling.
Information about nutrients in kitchen sinks was found in literature but most of the references were old and the studies had been performed in different ways and in different countries, which made it difficult to compare them. Values from a Swedish report in 1994 were considered the most reliable ones and were later used in the mass balance.

An attempt to improve the existing mass balance, which was initiated in a previous study, was conducted. New values, from both literature and new analysis were therefore used. The result indicated large differences for nitrogen but low differences for phosphorous. The mass balance also showed that the majority of TS and COD were transported away in the outflow.
Except for more analysis at Fullriggaren, updated research about nutrients in Swedish kitchens sinks would be necessary to further improve the mass balance since values that were used in this mass balance were from a day care center in 1994. Investigations of food waste from households in present time would further increase the reliability. (Less)
Popular Abstract (Swedish)
Matavfallskvarnar är ett smidigt sätt att samla in matavfall på. Med nya system behöver matavfallet inte transporteras till reningsverket utan kan istället lagras i tankar för att sedan köras direkt till biogasanläggningen. Här produceras biogas av matavfallet genom rötning.

Biogas är en förnybar energikälla som bland annat kan användas som fordonsbränsle, uppvärmning och elproduktion. Genom att röta matavfall kan biogas framställas. Den vanligaste metoden för att samla in matavfall i Sverige är med papperspåsar. Matavfallskvarnar är ännu ovanligt i Sverige och många städer tillåter inte att de installeras på grund av att ledningarna inte klarar större mängder matavfall. Ett annat sätt att samla in matavfallet från matavfallskvarnarna... (More)
Matavfallskvarnar är ett smidigt sätt att samla in matavfall på. Med nya system behöver matavfallet inte transporteras till reningsverket utan kan istället lagras i tankar för att sedan köras direkt till biogasanläggningen. Här produceras biogas av matavfallet genom rötning.

Biogas är en förnybar energikälla som bland annat kan användas som fordonsbränsle, uppvärmning och elproduktion. Genom att röta matavfall kan biogas framställas. Den vanligaste metoden för att samla in matavfall i Sverige är med papperspåsar. Matavfallskvarnar är ännu ovanligt i Sverige och många städer tillåter inte att de installeras på grund av att ledningarna inte klarar större mängder matavfall. Ett annat sätt att samla in matavfallet från matavfallskvarnarna är att leda det till nergrävda tankar för att sedan regelbundet tömma dessa med en slamsugbil.

I kvarteret Fullriggaren i Västra Hamnen i Malmö installerades ett sådant system redan vid nybyggnationen år 2012. På grund av det stora antalet lägenheter är systemet uppdelat i två slingor, västra och östra. Tankarna är uppbyggda på olika vis. Den västra tanken har en stor försedimenteringstank medan den östra tanken endast består av en sedimenteringstank.

För att utvärdera detta system och speciellt för att se om det finns någon skillnad mellan västra och östra tanken har prov tagits ut. Detta gjordes med ett långt rör som fördes ner i tanken för att provet skulle bli så representativt som möjligt.

III
Rötförsök gjordes för att mäta hur mycket biogas som matavfallet kan generera och det visade sig att matavfallet från de två tankarna producerade olika mycket biogas. Även jämfört med tidigare studier som gjorts i samma område varierade resultaten. Slutsatsen blir att tankarnas olika uppbyggnad inte påverkar biogaspotentialen. Det är snarare så att det är matavfallets innehåll som spelar roll och detta beror ju på vad de boende äter och sedan spolar ner i köksavloppet.
Analyser gjordes på matavfallet samt på utloppet från tanken. Med dessa siffror samt med kompletterande data från litteratur kunde en massbalans göras. Härifrån kunde det ses att majoriteten av torrsubstansen matavfall transporterades ut från tanken via utloppet. Det finns många faktorer som gör att denna iakttagelse inte behöver stämma till fullo. Till exempel togs prover från utloppet ut precis innan tanken tömts. Då var tankarna helt fulla vilket kan ha bidragit till att mycket material transporterades vidare i utloppet.

I en rapport från 2014 redovisas en statistisk undersökning där slumpmässigt utvalda hushåll i några dagar fick registrera hur mycket onödigt matavfall de spolar ut i sitt köksavlopp. Utifrån resultatet i denna rapport gjordes en analys på mängden näringsämnen som detta onödiga matavfall genererar. Det visade sig att mejeriprodukter var den kategori som genererar största mängden näringsämnen i form av torrsubstans, kväve och fosfor. (Less)
Please use this url to cite or link to this publication:
author
Magnusson, Nicolina LU
supervisor
organization
course
VVA820 20151
year
type
H2 - Master's Degree (Two Years)
subject
keywords
vattenförsörjningsteknik, avloppsteknik, water engineering, environmental engineering
language
Swedish
id
7371965
date added to LUP
2015-06-24 11:25:58
date last changed
2016-02-04 15:03:49
@misc{7371965,
  abstract     = {To collect, treat and use food waste is desirable in society in order to recycle and efficiently use all resources. One stage of one of the Swedish environmental goals is to collect and treat 50 % of the food waste biologically in year 2018. A useful product from this treatment is biogas, which can be used for fueling vehicles, heating and producing electricity. Biogas could be produced from food waste by anaerobic digestion.

Fullriggaren is a neighborhood consisting of 600 apartments in the Western Harbor in Malmö. Food waste disposers were already installed during the construction in 2012. The food waste disposers are installed directly in the kitchens sinks and all water from the kitchen is lead and pumped into the tank. There are two tanks and the area is split into two systems; east and west.

This report is a continual evaluation of the neighborhood Fullriggaren based on an earlier study. The aim was to investigate if there is a difference in methane potential in the two systems. The existing mass balance needed to be improved with new background levels. Therefore a small literature study regarding nutrients from kitchen sinks was performed. An investigation about the avoidable food waste in kitchen sinks included an estimate of the distribution of every product in each waste category. This was based on the result from a report where the amount of avoidable food waste was poured into the sink and then measured in randomly selected households. The purpose with this study was to obtain a reliable background value to use in the mass balance.

The methane potential was measured in three bio methane potential (BMP) tests. The food waste from the western system generated more methane than the food waste from the eastern system, 593 respectively 543 Nml CH4/g VS. During the three performed BMP-tests, differences between the eastern and the western tank were observed. Compared to earlier studies, the result shows the opposite with highest methane production in the eastern tank. The conclusion is that the amount methane gas varies in different time occasions and seems to depend on the composition of the food waste during each sampling.
Information about nutrients in kitchen sinks was found in literature but most of the references were old and the studies had been performed in different ways and in different countries, which made it difficult to compare them. Values from a Swedish report in 1994 were considered the most reliable ones and were later used in the mass balance.

An attempt to improve the existing mass balance, which was initiated in a previous study, was conducted. New values, from both literature and new analysis were therefore used. The result indicated large differences for nitrogen but low differences for phosphorous. The mass balance also showed that the majority of TS and COD were transported away in the outflow.
Except for more analysis at Fullriggaren, updated research about nutrients in Swedish kitchens sinks would be necessary to further improve the mass balance since values that were used in this mass balance were from a day care center in 1994. Investigations of food waste from households in present time would further increase the reliability.},
  author       = {Magnusson, Nicolina},
  keyword      = {vattenförsörjningsteknik,avloppsteknik,water engineering,environmental engineering},
  language     = {swe},
  note         = {Student Paper},
  title        = {Utvärdering av matavfallskvarnssystem i kv. Fullriggaren, Västra Hamnen i Malmö},
  year         = {2015},
}