The effect of cow dung biochar on water hyacinth anaerobic digestion of with control setup (without biochar (T${}_0$) was investigated using a batch scale setup (at 35 °C). Biochar was applied in three doses (v/v) 0.5% (T${}_{0.5}$), 1% (T${}_1$), and 1.5% (T${}_{1.5}$) in anaerobic digestion setups and daily and cumulative biogas formation was recorded in all setups. Results revealed that biochar addition reduced the lag phase from 3 d to 1 d but extended in a higher dose (1.5%). The cumulative biogas production was fund to be 2721 mL in T${}_1$ followed by, 2388 mL (T${}_{0.5}$), 1940 mL (T${}_{1.5}$), and 1153 mL (T${}_0$) ($p<0.001$ for all) by the end of 35 days of the AD process. The maximum biogas production improved by 40.6–57.6%, in biochar setups than T${}_0$. Spent slurry was analyzed for its possible use as biomanure for plant production and results revealed a considerable amount (g kg${}^{-1}$) of total nitrogen (14.07–16.69), total phosphorous (15.76–17.8), total potassium (21.56–24.12) in spent slurry from biochar-amended setups. Carbon-to-nitrogen ratio (14.2–19.6), NH${}_4$ ${}^{+}$/NO${}_3$-N (<0.16 g Kg${}^{-1}$) ratio, and germination index of spent slurry was also in the acceptable limit as decided for biomanure, indicating its possible in plant production. Biochar addition (up to 1%) improves the biomethane contents (4.4–11%) in biogas and nutritional value of spent slurry. This study indicates that weed Eichhornia biomass could be managed effectively by anaerobic digestion for methane-rich biogas and biofertilizer production simultaneously under the circular economy model.

对照设置下牛粪生物炭对水葫芦厌氧消化的影响（无生物炭（T${}_0$）是使用批次刻度设置（在35°C下）进行调查的。以3剂量（v / v）0.5％（T${}_{0。5}$），1％（T${}_{\mathrm{1个}}$）和1.5％（T${}_{\mathrm{1个}。5}$）在厌氧消化设置中，并在所有设置中记录每日和累积的沼气形成。结果表明，生物炭的添加将迟滞期从3天减少到1天，但以更高的剂量（1.5％）延长。累计沼气产量为2721 mL T${}_{\mathrm{1个}}$ 其次是2388 mL（T${}_{0。5}$），1940毫升（T${}_{\mathrm{1个}。5}$）和1153 mL（T${}_0$）（$p<0。001$（对于所有人而言），直到广告流程结束35天。在生物炭设置中，最大沼气产量提高了40.6–57.6％。${}_0$。分析了废浆液可能用作植物生产中的生物肥料的结果，结果显示相当数量（g千克）${}^{-\mathrm{1个}}$）中的总氮（14.07–16.69），总磷（15.76–17.8），总钾（21.56–24.12）来自经过生物炭改良的废浆。碳氮比（14.2-19.6），NH${}_4$ ${}^{+}$/没有${}_3$-N（<0.16千克Kg${}^{-\mathrm{1个}}$比例和废浆液的发芽指数也在生物肥料决定的可接受范围内，表明其可能在植物生产中使用。添加生物炭（最多1％）可提高沼气中生物甲烷含量（4.4-11％），并提高废浆液的营养价值。这项研究表明，在循环经济模式下，通过厌氧消化富甲烷沼气和生产生物肥料可以有效地治理凤眼兰的生物量。