Biohythane production from pineapple peel using Methanosarcina mazei enhanced with palm oil mill effluent (POME) sludge in single-stage anaerobic digestion

Biohythane production via single-stage anaerobic digestion (AD) is an effective way for sustainable energy recovery from lignocellulosic biomass. In this paper, biohythane was produced through the AD process from pineapple peel waste substrate using purely cultured Methanosarcina mazei with the enhancement of palm oil mill effluent (POME) sludge as the inoculum. This study focuses on the effects of the lignocellulosic pre-treatment method, the addition of POME sludge into M. mazei culture medium as inoculum, and various operational conditions (food to microorganisms (F/M) ratios, temperature, pH) on gas production performances. The experimental results indicate that these parameters influenced the efficiency of biohythane production by producing the peak maximum biohythane production rate values (HPR_max) and (MPR_max), H₂:CH₄ = 1.93:0.67 L/L-d, and biohythane yield (HY) and (MY), H₂:CH₄ = 1.18:0.55 mL/L-substrate. This study demonstrates that biohythane gas (H₂ + CH₄ + CO₂) production from pineapple waste can be accelerated by M. mazei only with the enhancement of POME sludge through single-stage AD system under mesophilic batch process conditions.     

西宁市农牧源氨排放清单及其分布特征

以西宁市为研究区域,通过实地调研获得西宁市农牧源活动水平数据,利用排放因子法编制了西宁市2018年农牧源氨排放清单.分析了西宁市农牧源氨排放特征,利用ArcGIS进行3 km×3 km的空间网格化分配,利用蒙特卡罗模拟对畜禽养殖和氮肥施用氨排放清单进行不确定性分析.结果表明,西宁市2018年农牧源氨排放总量为4 644...     

热-碱处理污泥与木耳菌糠共发酵产酸性能的研究

为克服单一剩余活性污泥(WAS)发酵产酸效率低的问题和资源化利用废弃木耳菌糠(SMS),本文对热-碱预处理污泥(PWS)和菌糠进行共发酵,研究预处理和菌糠添加对共发酵体系的产酸性能影响.试验基于原料的总固体含量(TS)共设置6个处理,分别为污泥(WAS∶SMS=1∶0)、预处理污泥(PWS∶SMS=1∶0)、菌糠(PW...     

厌氧工艺对含铬(Ⅵ)废水处理效果初探

以砂石和活性炭作为填料,自制厌氧生物滤床系统,并对系统进行驯化,发现完成驯化后的稳定系统具有良好的去铬(Ⅵ)能力.废水在系统中经过2 h运行,加入碳源的试验组与不加碳源的对照组的铬(Ⅵ)去除率分别为87.33%和66.31%.恒流泵最佳流量为47 mL/min,外加碳源后,铬(Ⅵ)的浓度由60 mg/L左右降到0.5 mg/L以下,需要4 h,而对照组需要14 h,铬(Ⅵ)浓度由64.66 mg/L提高到 75.53 mg/L时,对本系统负面影响甚微,提高到95.47 mg/L时,系统出水达标所需时间延长到7.5 h.本系统具有耐受一定程度的浓度冲击以及进一步驯化、提高处理负荷的潜力.     

基于秸秆后发酵产沼气的一次发酵时间优化

采用"一次发酵+NaOH处理+二次发酵"工艺,以稻秸为原料,研究一次发酵时间对稻秸沼气发酵的影响.结果表明,一次发酵后的稻秸仍有一定的产气能力,干物质(TS)产气量为28.11～50.73mL/g TS,产气量大小与一次发酵时间成反比;一次发酵后的稻秸经NaOH处理后,稻秸物质结构受到明显破坏,有机物大量溶出,稻秸浸提...     

单级SBR生物膜中全程自养脱氮的研究

研究了具有全程自养脱氮作用的生物膜中无机碳源浓度、pH值、溶解氧(DO)对全程自养脱氮的影响.结果表明,当NaHCO3浓度从1.75g/L上升到2.50g/L时,反应体系中的pH值从7.6～8.0上升到8.8左右,氨氮转化率和总无机氮去除率分别急剧下降到53%和48.8%.在进水氨氮负荷为60g/(m³·d)时,最佳DO应控制在0.5～0.7mg/L,此时氨氮转化率达到90%以上.     

磁性铁基改性生物炭去除水中氨氮

氨氮的过度排放是水体富营养化的一个重要原因.然而,随着环境法规的日益严格,传统方法处理效果难以达到要求.吸附法因高效、安全等优点近年来开始应用于去除水中的氨氮.本研究中以共沉淀法将磁性铁基材料负载到市政污泥生物炭上,结果表明其对水中氨氮有良好的去除效果.80℃下合成的材料（MB₈₀）在293 K下对氨氮的饱和吸附量可达17.52 mg·g^-1.动力学与热力学结果表明,MB₈₀吸附氨氮的过程更符合伪二级动力学和Langmuir等温线.MB₈₀对氨氮的吸附机制可归纳为静电吸引、孔隙填充、离子交换和氢键结合.且5次循环后对氨氮的吸附量仍十分理想,可达3.18 mg·g^-1.本研究的结果可以为高效去除水中氨氮提供一种行之有效的方法,并为市政污泥的处理提供新的出路.     

包埋固定化硝化污泥处理氨氮废水的过程特性

采用聚乙烯醇（PVA）包埋硝化效能良好的活性污泥制备固定化颗粒,针对不同初始氨氮浓度的模拟废水,基于序批式间歇反应器小试实验,探讨了包埋颗粒的传质效能与氮去除过程特性.实验结果表明：颗粒体积投加率为10%,实验水温为26~30℃,pH值为7.5~8.5,反应器DO浓度为4~5mg/L的条件下,各初始氨氮浓度（50~400mg/L）稳定期包埋颗粒最大氨氮去除负荷为61.8~242.3mgN/（L-particles·h）.包埋颗粒对氨氮的去除较符合零级反应动力学模型,其最大氨氧化速率（μ_max）为271.40mgN/（L-particles·h）,半饱和常数K_s为66.69mg/L,包埋颗粒内氨和氧的有效扩散系数（D_e）分别为0.467×10^-9m²/s、0.279×10^-9m²/s.SEM观察和比表面积测试结果表明,与新鲜颗粒相比,稳定期颗粒内部的比表面积和平均孔径增加.包埋颗粒,活性污泥,包埋颗粒与活性污泥混合3种体系对比实验表明,各初始氨氮浓度条件下混合体系可显著强化生物硝化与脱氮过程,并发生同时硝化反硝化现象.     

纹缟虾虎鱼对Cu~(2+)、Cd~(2+)和氨氮的毒性响应和敏感性分析

以纹缟虾虎鱼为受试生物,分别进行了Cu~(2+)、Cd~(2+)和氨氮为环境因子的急性毒性实验和氨氮慢性暴露实验,结合文献数据分析纹缟虾虎鱼对3种污染物的敏感性。结果表明,Cu~(2+)、Cd~(2+)和氨氮对纹缟虾虎鱼的EC50分别为4.527、40.408和63.182mg·L~(-1)。组织切片结果显示,氨氮暴露能够引起纹缟虾虎鱼肝组织结构退化,组织细胞畸变,其损伤程度随着氨氮浓度的升高而加剧。氨氮暴露对肠管未见明显影响。敏感性分析结果表明,纹缟虾虎鱼对Cu~(2+)、Cd~(2+)和氨氮的累积概率分别为83.33%、96.27%和90.48%,均表现为不敏感。在Cu~(2+)、Cd~(2+)和氨氮对海洋生物的敏感性排名中,纹缟虾虎鱼分别在第31/35、32/32和19/20位。在8~12种海洋鱼类中,纹缟虾虎鱼对上述3种污染物的敏感性都处在较低水平。     

Microprofiles of activated sludge aggregates using microelectrodes in completely autotrophic nitrogen removal over nitrite (CANON) reactor

Microsensor measurements and fluorescence in situ hybridization (FISH) analysis were combined to investigate the microbial populations and activities in a laboratory-scale sequencing batch reactor (SBR) for completely autotrophic nitrogen removal over nitrite (CANON). Fed with synthetic wastewater rich in ammonia, the SBR removed 82.5±5.4% of influent nitrogen and a maximum nitrogen-removal rate of 0.52 kgN·m⁻³·d⁻¹ was achieved. The FISH analysis revealed that aerobic ammonium-oxidizing bacteria (AerAOB) Nitrosomonas and anaerobic ammonium-oxidizing bacteria (AnAOB) dominated the community. To quantify the microbial activities inside the sludge aggregates, microprofiles were measured using pH, dissolved oxygen (DO), NH4+, NO2− and NO3− microelectrodes. In the outer layer of sludge aggregates (0–700 μm), nitrite-oxidizing bacteria (NOB) showed high activity with 4.1 μmol·cm⁻³·h⁻¹ of maximum nitrate production rate under the condition of DO concentration higher than 3.3 mg·L⁻¹. Maximum AerAOB activity was detected in the middle layer (depths around 1700 μm) where DO concentration was 1.1 mg·L⁻¹. In the inner layer (2200–3500 μm), where DO concentration was below 0.9 mg·L⁻¹, AnAOB activity was detected. We thus showed that information obtained from microscopic views can be helpful in optimizing the SBR performance.