Anaerobic digestion of mixed silage of waterweed biomass and wheat straw in a long-term semi-continuous biogas production process

Table 3 Parameters and analytical methods for the evaluation of the digestate

Parameter	Sample pre-treatment	Analytical methods
TS	None	DIN 12880
VS	None	DIN 12879
VFA/TAC	Sieved	Titration method according to Lili et al. [13], Burete Digital BRAND, Microprocessor pH-Meter pH 95 (WTW, Weilheim, Germany)
NH₄-N	Filtered	DIN 38406 E5. Spektroquant® test kit (measuring range 0.01–3 mg L⁻¹ NH₄-N, Merck, Germany), photometric measurement with MultiLab P5 (WTW, Weilheim, Germany)
Acetate, propionate, butyrate	Filtered	HPLC (Shimadzu, Japan); detector: RID-10A; column: VA 300/7.8 Nucleogel Ion 300 OA; eluent 0.05 M H₂SO₄
Water-soluble elements	Filtered	Inductively coupled plasma atomic emission spectrometry ICP-AES (Spectroflame, Spectro Int., Kleve, Germany)

ISSN: 2192-0567