Compost
Ken ThompsonISBN: 978 0 7566 1341 9
Compost basics
People write college theses on compost, but
don’t let that worry you—all the science you
need to know is in the next twelve pages.
Essentially, the perfect compost pile needs
the right mix of ingredients, plenty of water
(but not too much), warmth, and lots of air.
A balanced diet
Ultimately, animals and microorganisms that turn plant material
into compost need to eat the same things that you do. They need
energy, most conveniently supplied by carbohydrates. In your case,
this means starch and sugars from bread, potatoes, rice, and fruit.
The main carbohydrate in plants is cellulose—you can’t break this
down, but compost microorganisms can. They also need nitrogen
and phosphorus, to make proteins and other vital molecules.
Carbohydrates contain carbon, which provides energy and
is the main structural element of living organisms. In practice,
anything that contains plenty of nitrogen usually also has lots of
phosphorus and other essential elements. A useful, shorthand way
to describe compost ingredients is therefore by referring to their
carbon:nitrogen, or C:N, ratio.
To understand why this ratio needs to be correct, a useful
analogy is your own diet. Without even thinking about it, you
aim to eat a balance of these two crucial elements: meat sauce
and pasta; fish and chips; cheese and bread; burger and fries; roast
beef and mashed potatoes.
You know that the perfect sandwich contains more bread
than ham or peanut butter and, in a similar fashion, your compost
pile needs more carbon than nitrogen.
Some C:N ratios
• poultry manure has a C:N ratio
of only 6
• vegetable kitchen waste is about 15
• grass cuttings average around 20
• tree leaves are about 50
• straw hovers around 80
• wood and paper are much higher, at anywhere
from 100 to 500
This means, for example, that grass cuttings
are relatively nitrogen-rich, whereas wood is
mostly carbon.
Jag orkar inte söka nu, men Jordbrukstekniska institutet, Uppsala har många intressanta "JTI-rapporter"! När det gäller biogas så finns bl.a. denna:
KRETSLOPP & AVFALL
Nr 21
Gårdsbaserad biogas på
Plönninge naturbruksgymnasium
En förstudie med det tyska konceptet som grund
I detta examensarbete, som utförts på uppdrag av Landstinget Halland, har en för-
studie angående uppförandet av en gårdsbaserad biogasanläggning på Plönninge
naturbruksgymnasium genomförts. I rapporten ingår litteraturstudie och inventering
av lämpliga rötningssubstrat inklusive satsvis utrötning av hästgödsel och
svampkompost (odlingssubstrat för champinjoner). Vidare har det utförts en grov
dimensionering av två alternativa storlekar med förslag på huvudkomponenter i
en gårdsbaserad biogasanläggning på Plönninge, samt en ekonomisk kalkyl över
investering och drift av biogasanläggningen och en ekonomisk känslighetsanalys.
Postat: 04 nov 2009 21:50
