Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system

In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state(UASS)with anaerobic filter(AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0–431 m L O2/gvswere conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431 m L O2/gvsincreased the methane yield by 82.2%. Aeration intensities of 0–355 m L O2/gvswere conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen(DO) of UASS and AF reactors kept around 1.39 ±0.27 and 0.99 ± 0.38 mg/L, respectively. p H was relatively stable around 7.11 ± 0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85 ± 7 m L/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.     

Potential of anaerobic digestion for material recovery and energy production in waste biomass from a poultry slaughterhouse

This study was carried out to assess the material and energy recovery by organic solid wastes generated from a poultry slaughterhouse. In a poultry slaughterhouse involving the slaughtering of 100,000 heads per day, poultry manure & feather from the mooring stage, blood from the bleeding stage, intestine residue from the evisceration stage, and sludge cake from the wastewater treatment plant were discharged at a unit of 0.24, 4.6, 22.8, and 2.2 Mg day^?1, consecutively. The amount of nitrogen obtained from the poultry slaughterhouse was 22.36 kg 1000 head^?1, phosphate and potash were 0.194 kg 1000 head^?1 and 0.459 kg 1000 head^?1, respectively. As regards nitrogen recovery, the bleeding and evisceration stages accounted for 28.0% and 65.8% of the total amount of recovered nitrogen. Energy recovered from the poultry slaughterhouse was 35.4 N m³ 1000 head^?1 as CH₄. Moreover, evisceration and wastewater treatment stage occupied 88.1% and 7.2% of the total recovered CH₄ amount, respectively.     

The operation of cost-effective on-site process for the bio-treatment of mixed municipal solid waste in rural areas

The application of on-site waste treatment significantly reduces the need for expensive waste collection and transportation in rural areas; hence, it is considered of fundamental importance in developing countries. In this study, the effects of in-field operation of two types of mini-scale on-site solid waste treatment facilities on de-centralized communities, one using mesophilic two-phase anaerobic digestion combined with composting (TPAD, 50 kg/d) and another using decentralized composting (DC, 0.6–2 t/d), were investigated. Source-separated collection was applied to provide organic waste for combined process, in which the amount of waste showed significant seasonal variation. The highest collection amount was 0.18 kg/capital day and 0.6 kg/household day. Both sites showed good performance after operating for more than 6 months, with peak waste reduction rates of 53.5% in TPAD process and 63.2% in DC process. Additionally, the windrow temperature exceeded 55 °C for >5 days, indicating that the composting products from both facilities were safe. These results were supported by 4 days aerobic static respiration rate tests. The emissions were low enough to avoid any impact on nearby communities (distance <100 m). Partial energy could be recovered by the combined process but with complicated operation. Hence, the choice of process must be considered in case separately.     

Experimental and life cycle assessment analysis of gas emission from mechanically–biologically pretreated waste in a landfill with energy recovery

The global gaseous emissions produced by landfilling the Mechanically Sorted Organic Fraction (MSOF) with different weeks of Mechanical Biological Treatment (MBT) was evaluated for an existing waste management system. One MBT facility and a landfill with internal combustion engines fuelled by the landfill gas for electrical energy production operate in the waste management system considered. An experimental apparatus was used to simulate 0, 4, 8 and 16 weeks of aerobic stabilization and the consequent biogas potential (Nl/kg) of a large sample of MSOF withdrawn from the full-scale MBT. Stabilization achieved by the waste was evaluated by dynamic oxygen uptake and fermentation tests. Good correlation coefficients (R²), ranging from 0.7668 to 0.9772, were found between oxygen uptake, fermentation and anaerobic test values. On the basis of the results of several anaerobic tests, the methane production rate k (year^?1) was evaluated. k ranged from 0.436 to 0.308 year^?1 and the bio-methane potential from 37 to 12 N m³/tonne, respectively, for the MSOF with 0 and 16 weeks of treatment. Energy recovery from landfill gas ranged from about 11 to 90 kW h per tonne of disposed MSOF depending on the different scenario investigated. Life cycle analysis showed that the scenario with 0 weeks of pre-treatment has the highest weighted global impact even if opposite results were obtained with respect to the single impact criteria. MSOF pre-treatment periods longer than 4 weeks showed rather negligible variation in the global impact of system emissions.     

常温厌氧消化技术处理城市生活有机垃圾的中试研究

对分类收集的城市生活有机垃圾采用专门设计的兼氧沤解预液化—常温厌氧消化的工艺技术进行处理。试验结果显示 ,兼氧沤解对生活有机垃圾的预液具有较好的效果 ,液化率达 80 %以上 ,可以满足反应器对生活有机垃圾预处理的要求     

Enhanced methane production during long-term UASB operation at high organic loads as enabled by the immobilized Fungi

• Fungi enable the constant UASB operation even at OLR of 25.0 kg/(m³×d). • The COD removal of 85.9% and methane production of 5.6 m³/(m³×d) are achieved. • Fungi inhibit VFAs accumulation and favor EPS generation and sludge granulation. • Fungi enrich methanogenic archaea and promote methanogenic pathways. Anaerobic digestion is widely applied in organic wastewater treatment coupled with bioenergy production, and how to stabilize its work at the high organic loading rate (OLR) remains a challenge. Herein, we proposed a new strategy to address this issue via involving the synergetic role of the Aspergillus sydowii 8L-9-F02 immobilized beads (AEBs). A long-term (210-day) continuous-mode operation indicated that the upflow anaerobic sludge bed (UASB) reactor (R1, with AEBs added) could achieve the OLR as high as 25.0 kg/(m³×d), whereas the control reactor (R0, with AEBs free) could only tolerate the maximum OLR of 13.3 kg/(m³×d). Remarkably, much higher COD removal (85.9% vs 23.9%) and methane production (5.4 m³/(m³×d) vs 2.2 m³/(m³×d)) were achieved in R1 than R0 at the OLR of 25.0 kg/(m³×d). Such favorable effect results from the facts that fungi inhibit VFAs accumulation, favor the pH stabilization, promote the generation of more extracellular polymeric substance, and enhance the sludge granulation and settleability. Moreover, fungi may enhance the secretion of acetyl-coenzyme A, a key compound in converting organic matters to CO₂. In addition, fungi are favorable to enrich methanogenic archaea even at high OLR, improving the activity of acetate kinase and coenzyme F₄₂₀ for more efficient methanogenic pathway. This work may shed new light on how to achieve higher OLR and methane production in anaerobic digestion of wastewater.     

复合式厌氧污泥床反应器处理城市生活污水的研究

复合式厌氧污泥床反应器是一种改进的厌氧处理工艺，可有效去除城市生活污水中的污染物，并提高了污水的可生化性，是一种较为理想的城市污水强化一级处理工艺。本文对该工艺，装置的特点和效果进行分析,并展望其应用前景。     

城镇生活污水的低温厌氧生物处理技术研究与应用进展

归纳了厌氧过程处理低温生活污水的运行机制和影响因素总结了污水中典型污染物的去除特征评述了国内外厌氧反应器对低温生活污水的处理效能以及如何通过改进反应器自身结构及运行参数来应对低温、低浓度对厌氧反应器运行的不利影响最后介绍了厌氧反应器在资源化利用和能源回收方面的应用以及实际工程案例,并指出了存在的问题与今后研究的方向。     

Fe~0-厌氧微生物体系在难降解废水领域的应用

Fe0-厌氧微生物联用技术是将Fe0直接介入厌氧反应器内或者将Fe0内电解工艺作为厌氧生物处理工艺的预处理工艺进行联用处理的一种新的水处理处理技术。通过大量的实验论证可以得出Fe0-厌氧生物体系在处理多种难降解有机物及高浓度盐废水都有很好的处理效果。     

不同COD浓度下低基质厌氧氨氧化的启动特征

采用厌氧序批式反应器(ASBR)处理NH4+-N和NO2--N浓度分别为(25. 00±0. 40) mg·L~(-1)和(33. 00±0. 60) mg·L~(-1)的模拟废水,在温度为30℃时,投加乙酸钠控制COD浓度分别为5. 00、15. 00、30. 00和50. 00 mg·L~(-1),研究对厌氧氨氧化启动的影响.结果表明:①4种COD浓度下分别经过74、94、106和129 d均能成功启动厌氧氨氧化. COD浓度为15. 00 mg·L~(-1)和30. 00 mg·L~(-1)时,反应器脱氮性能较好,稳定运行后,平均出水NH4+-N浓度分别为1. 98 mg·L~(-1)和1. 89 mg·L~(-1),平均出水NO2--N浓度低于0. 62 mg·L~(-1),平均出水TN浓度分别为2. 37、2. 28 mg·L~(-1);②启动过程中反硝化对脱氮的平均贡献率逐渐降低至4. 78%、9. 59%、10. 21%和36. 50%,厌氧氨氧化对脱氮的平均贡献率逐渐上升至95. 22%、90. 41%、89. 79%和63. 50%;③厌氧氨氧化活性分别在第44、76、86和114 d时超过反硝化活性,最后分别达到0. 700、0. 690、0. 670和0. 510mg·(g·h)~(-1),反硝化活性分别为0. 110、0. 130、0. 240和0. 410 mg·(g·h)~(-1).该研究结果可为厌氧氨氧化技术在实际工程中的应用提供参考.