Civil Engineering, Lebanese American University, 301 Bassil Building, Byblos, Lebanon.
The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA.
Sci Rep. 2022 Jun 22;12(1):10529. doi: 10.1038/s41598-022-14425-1.
Resource recovery and prevention of environmental pollution are key goals for sustainable development. It is widely reported that agro-industrial activities are responsible for the discharge of billions of liters of wastewater to the environment. Anaerobic digestion of these energy rich agro-industrial wastewaters can simultaneously mitigate environmental pollution and recover embedded energy as methane gas. In this study, an assessment of mono- and co-digestion of cheese whey wastewater (CWW) and poultry slaughterhouse wastewater (PSW) was conducted in 2.25-L lab-scale anaerobic digesters. Treatment combinations evaluated included CWW (R1), PSW (R2), 75:25 CWW:PSW (R3), 25:75 CWW:PSW (R4), and 50:50 CWW:PSW (R5). The digestion efficiencies of the mixed wastewaters were compared to the weighted efficiencies of the corresponding combined mono-digested samples. R4, with a mixture of 25% CWW and 75% PSW, achieved the greatest treatment efficiency. This corresponded with an average biodegradability of 84%, which was greater than for R1 and R2 at 68.5 and 71.9%, respectively. Similarly, R4 produced the highest average cumulative methane value compared to R1 and R2 at 1.22× and 1.39× for similar COD loading, respectively. The modified Gompertz model provided the best fit for the obtained methane production data, with lag time decreasing over progressive treatment cycles. PCoA and heatmap analysis of relative microbial abundances indicated a divergence of microbial communities based on feed type over the treatment cycles. Microbial community analysis showed that genus Petrimonas attained the highest relative abundance (RA) at up to 38.9% in the first two cycles, then subsequently decreased to near 0% for all reactors. Syntrophomonas was highly abundant in PSW reactors, reaching up to 36% RA. Acinetobacter was present mostly in CWW reactors with a RA reaching 56.5%. The methanogenic community was dominated by Methanothrix (84.3-99.9% of archaea). The presence of phosphate and Acinetobacter in CWW feed appeared to reduce the treatment efficiency of associated reactors. Despite Acinetobacter being strictly aerobic, previous and current results indicate its survival under anaerobic conditions, with the storage of phosphate likely playing a key role in its ability to scavenge acetate during the digestion process.
资源回收和防止环境污染是可持续发展的关键目标。据广泛报道，农业工业活动导致数十亿升废水排放到环境中。对这些富含能源的农业工业废水进行厌氧消化可以同时减轻环境污染并回收嵌入的甲烷气体。在这项研究中，在 2.25 升实验室规模的厌氧消化器中对奶酪乳清废水（CWW）和家禽屠宰废水（PSW）的单独和共消化进行了评估。评估的处理组合包括 CWW（R1）、PSW（R2）、75:25 CWW:PSW（R3）、25:75 CWW:PSW（R4）和 50:50 CWW:PSW（R5）。将混合废水的消化效率与相应的组合单相消化样品的加权效率进行了比较。R4，即 25%的 CWW 和 75%的 PSW 的混合物，实现了最高的处理效率。这对应于平均生物降解率为 84%，高于 R1 和 R2 的 68.5%和 71.9%。同样，R4 在类似 COD 负荷下产生的平均累积甲烷值最高，分别比 R1 和 R2 高 1.22×和 1.39×。修正的 Gompertz 模型为获得的甲烷生产数据提供了最佳拟合，滞后时间随着处理周期的推进而减少。PCoA 和相对微生物丰度的热图分析表明，基于饲料类型，微生物群落在处理周期中存在分歧。微生物群落分析表明，Petrimonas 属的相对丰度（RA）最高，在前两个周期达到 38.9%，然后所有反应器的 RA 均降至接近 0%。Syntrophomonas 在 PSW 反应器中含量丰富，RA 高达 36%。Acinetobacter 主要存在于 CWW 反应器中，RA 达到 56.5%。产甲烷菌群落主要由 Methanothrix（古菌的 84.3-99.9%）组成。CWW 进料中的磷酸盐和 Acinetobacter 的存在似乎降低了相关反应器的处理效率。尽管 Acinetobacter 是严格需氧的，但之前和现在的结果表明它在厌氧条件下存活，而磷酸盐的储存可能在其在消化过程中利用乙酸盐的能力中发挥关键作用。
