TABLE 1.

Biogas plants and operating conditionsa

Biogas plantFeedstock components (% fresh wt of total feedstock)bReactor vol (m3)Organic loading rate (kgODS m−3 day−1)Retention time (days)Total biogas production (mBG3 m−3 day−1)dCH4 production (mCH43 m−3 day−1)dOperation temp (°C)pHTotal ammonia (g liter−1)eNH3-N (g liter−1)NH4+-N (g liter−1)VFA (gHAc eq. liter−1)
R1cCattle dung (18%), cattle sewage (41%), maize silage (38%), water (2.5%)3,6003.8412.901.536.87.61.60.081.521.4
R2Pig liquid manure (50%), maize silage (39%), turkey dung (9%)1,3002.9 ± 0.2 (2.5)30.2 ± 3.1 (35)3.6 ± 0.2 (3.4)1.9 ± 0.2 (1.8)44.6 ± 0.4 (44.0)8.2 ± 0.1 (8.3)4.3 ± 0.0 (4.3)1.15 ± 0.1 (1.23)3.11 ± 0.1 (3.03)7.6f
R3Pig liquid manure (57%), maize silage (40%)2,7003.9 ± 0.2 (3.9)47 ± 1.5 (48)2.5 ± 0.1 (2.7)1.3 ± 0.1 (1.4)38.5 ± 0.3 (38.7)7.7 ± 0.1 (7.6)2.0 ± 0.5 (1.5)0.12 ± 0.04 (0.08)1.85 ± 0.41 (1.42)2.5 ± 0.5 (2.8)
R4cMaize silage (82%), barley grain (12%), water (6%)3,6743.41082.61.444.77.52.60.372.232.1
R5Cattle liquid manure (64%), maize silage (37%), pig liquid manure (6%), turkey dung (2%)2,6404.2 ± 0.7 (4.0)36.0 ± 3.2 (34.0)NANA41.0 ± 0.1 (41.0)7.9 ± 0.1 (7.8)4.0 ± 0.0 (4.0)0.45 ± 0.04(0.38)3.55 ± 0.04(3.62)2.4f
R6Cattle liquid manure (76%), maize silage (13%), grass silage (5%), cattle dung (4%), grains (2%)1,9502.5 ± 0.3 (2.4)46.9 ± 1.4 (47.0)1.3 ± 0.1 (1.3)0.7 ± 0.0 (0.7)39.9 ± 0.8 (39.3)7.9 ± 0.3 (7.4)1.7 ± 0.0 (1.7)0.20 ± 0.08(0.06)1.50 ± 0.08(1.64)1.5f
  • a Data are shown are average values with standard deviations of a time period of 4 weeks before sampling (data of the sampling day are in parentheses). ODS, organic dry substance; BG, biogas; HAc eq., acidic acid equivalent of all organic acids; NA, not analyzed.

  • b For components representing ≥2% of the total.

  • c One-time sampling from biogas plant at the beginning of a measurement period.

  • d Data normalized with 273.15 K and 1,013.25 hPa.

  • e Sum of NH3-N and NH4+-N.

  • f Data from day of sampling.