200:5:1 (C:N:P ratio 200:5:1)
Also known as: carbon nitrogen phosphorus ratio
The ideal carbon-to-nitrogen-to-phosphorus ratio for anaerobic digestion feedstock — 200 parts carbon to 5 parts nitrogen to 1 part phosphorus ensures balanced microbial nutrition.
Last updated
Beyond definitions
Planning to start a CBG business?
Get the full business understanding — capex, regulations, machinery, vendor questions, and risk checks before you commit capital.
What is 200:5:1?
The ratio 200:5:1 represents the recommended balance of Carbon (C) : Nitrogen (N) : Phosphorus (P) for healthy anaerobic digestion feedstock. The numbers mean 200 parts carbon for every 5 parts nitrogen for every 1 part phosphorus, by mass. It is the macronutrient stoichiometry that the microbial consortium needs for balanced growth — carbon as the energy and building-block source, nitrogen for proteins and nucleic acids, phosphorus for ATP and cell-wall structures.
The ratio is more commonly expressed in simplified form as C:N at 20:1 to 30:1, since phosphorus is rarely the limiting nutrient in Indian feedstocks. The phosphorus component matters most for monoculture plants on lignocellulose (paddy straw, sugarcane trash) where natural phosphorus content is low and supplementation may be needed; in mixed-feedstock plants with cattle dung or food waste, phosphorus arrives naturally above the 1-part threshold.
The consequences of deviating from this stoichiometry are measurable. C:N too low (below 15:1) — excess nitrogen converts to ammonia (NH₃) which inhibits methanogens at concentrations above 1,500-3,000 mg N/L. Single-feedstock plants on poultry manure, slaughterhouse waste or high-protein food waste frequently hit ammonia inhibition. C:N too high (above 35:1) — nitrogen is limiting and microbial growth slows, even though biogas yield potential remains theoretically intact. Plants on dry paddy straw alone (C:N around 70:1) typically achieve only 40-60% of theoretical yield until nitrogen is supplemented.
Typical Indian feedstock C:N ratios are useful for blend planning. Cattle dung: 18-25:1 (close to optimum). Press mud: 25-35:1. Food waste: 15-25:1. Paddy straw: 60-80:1. Sugarcane trash: 100-150:1. Poultry manure: 8-12:1. The blending exercise is therefore: combine high-C-low-N feedstocks (straw, trash) with low-C-high-N feedstocks (poultry, slaughterhouse waste) to hit a blended C:N in the 22-28:1 sweet spot. For phosphorus, supplementation with rock phosphate or DAP at 5-15 kg per tonne of feedstock is occasionally needed for monoculture lignocellulosic plants. Lab analysis of the actual feedstock blend at commissioning is essential — textbook values are starting estimates, not substitutes for measurement.
Common questions about 200:5:1
Plain-English answers to what people most often ask.
Why is the C:N:P ratio different from the commonly cited C:N ratio of 20–30:1?
How do I measure the C:N:P ratio of my feedstock?
Want the full picture, not just the term?
Adhāra Viveka gives you structured clarity on capital-intensive recycling and renewable-energy sectors — before you commit money or engage vendors.