初级猪粪废水混合培养普通小球藻的研究

实验研究了初级猪粪废水混合培养一株普通小球藻(Chlorella vulgaris)的可行性。实验结果表明,初级猪粪废水可直接进行C.vulgaris的培养,不需要添加微量金属元素,生物量最大可达0.414 g/L,为在Bristol培养基培养的生物量的3.14倍。C.vulgaris可以耐受1 000 mg/L COD的猪粪水,在250~1 000 mg/L范围内,C.vulgaris生物量随初始COD的升高而升高,猪粪水中的营养物质被高效地去除,其中猪粪水中的总氮、总磷和氨氮的去除率分别达到了50%,60%和90%以上。C.vulgaris的油脂含量达到22.28%,实现了初级猪粪废水中微藻的生物量转化和资源化处理。     

生物流化床处理石化污水应用效果研究

洛阳技术研发中心开发的生物流化床反应器,考察其对不同水质污水的处理效果,分别对炼油污水、乙二醇污水、PTA污水和煤制乙二醇污水等四种污水进行了1～3个月的连续试验。试验表明,在炼油污水进水COD为300～800mg/L、NH_3-N为30～60mg/L的条件下,经处理后,出水COD80mg/L、NH_3-N15mg/L,污水的COD去除率85%,NH_3-N去除率90%;在乙二醇污水进水COD为1500～2500mg/L的条件下,经处理后,出水COD500mg/L;在PTA污水进水COD为1000～4700mg/L的条件下,出水COD300mg/L,去除率90%;在煤制乙二醇污水进水COD为200～2000mg/L、NH_3-N为18～130mg/L的条件下,处理后的出水平均COD60mg/L、去除率超过90%,平均NH_3-N 8mg/L、去除率大于85%。试验结果表明,生物流化床反应器具有比表面积大、微生物浓度高、容积负荷率和污泥负荷率高、传质快、耐冲击负荷能力强、处理效果好等特点,对不同水质的污水均能达到良好的处理效果。     

一体化生物滤池处理城市污水试验研究

通过试验研究一体化生物滤池对城市生活污水的处理效果。考察了水里停留时间(HRT)、COD容积负荷、填料高度、曝气强度等的影响。结果表明,在流量为85L/h、容积负荷在1.0～1.5kgCOD/(m3·d)、曝气强度在0.4～0.6L/(m2·s)之间时滤池水中COD和SS的去除率约为85%～90%,氨氮的去除率为61.7%。     

印染废水膜后浓水的深度处理工艺研究

采用Fenton法+反硝化生物滤(DN)池的深度处理工艺处理印染废水膜后(RO)浓水,考察了H2O2加药量、FeSO4.7H2O加药量、初始pH值和反应时间对Fenton法去除COD的影响,以及C/N、水力停留时间(HRT)对DN池去除NO3--N的影响.研究结果表明:在初始pH值为4,FeSO4·7H2O和H2O2的投加量分别为450mg/L、90mg/L,反应时间为1.5h时,COD去除率达到62％,出水COD71mg/L,色度15倍;DN池在C/N为8,HRT为2h时,出水NO3--N降低至0.52mg/L,NO3--N去除率达到96.8％.RO浓水经上述工艺处理后出水水质稳定达到《纺织染整工业水污染物排放标准》(GB4287-2012)表2限值.     

普通小球藻产油性能研究

以普通小球藻(Chlorella vulgaris)为研究对象,考察了培养时间、培养温度、起始p H、不同碳源、氮源以及不同碳氮组合对其生物量和油脂产率的影响。结果表明:当培养温度为28℃、起始p H为8,最优碳氮源分别是浓度为20 g/L的葡萄糖和浓度为1.0 g/L的尿素时,培养15 d收获,普通小球藻油脂产率可达到156.4mg/(L·d),比优化前提高51%,为今后扩大培养小球藻、提高其油脂产率奠定了理论基础。     

大连石化污水场二期技术特点和运行效果

大连石化污水场二期整体引进美国地球工程公司的工艺包,核心工艺单元设备选型全部采用进口,设计污水处理量为1000m3/h,总投资1.3亿元。预处理单元采用的是API隔油池和DAF气浮池,油含量平均去除率为27.94%,悬浮物平均去除率为61.73%,COD平均去除率为32.67%;生化处理单元包括A/O池和二沉池,油含量平均去除率为71.6%,硫化物平均去除率为91.52%,挥发酚平均去除率为99.82%,COD平均去除率为78.83%,氨氮平均去除率为94.15%,碱度平均去除率为54.67%;深度处理单元三级澄清池采用溶气气浮工艺,出水油含量为0.63mg/L,平均去除率为85.94%,悬浮物含量为4.98mg/L,平均去除率为85.13%,COD为44.48mg/L,平均去除率为42.88%,出水水质达到排放标准。对于工艺设计存在的问题,大部分已采取解决方法,尚未解决的也在进一步调整中。     

低氮胁迫对两种魏氏藻生长和油脂积累的影响

为了评价低氮胁迫对真眼点藻纲的两株高产油微藻(斧形魏氏藻和点状魏氏藻)的生长和油脂积累的影响,实验设计中将原改良BG-11培养基中的硝酸钠浓度降低为3.6 mmol/L(0.3 g/L)。结果表明:在此浓度下斧形魏氏藻和点状魏氏藻的最高生物量分别为8.21 g/L和9.07 g/L;两者的总脂、中性脂和总脂肪酸含量(占干重)都随着培养时间的延长而不断增加,培养至第18天时分别达到56.4%,64.7%;54%,63.3%;43.5%,45.5%。这两种微藻的主要脂肪酸都含有豆蔻酸、棕榈酸、棕榈油酸、油酸、亚油酸、花生四烯酸和二十碳五烯酸,均适合于生物柴油的生产。它们的总脂、中性脂和总脂肪酸的单位体积产率分别为0.257 g/(L·d),0.326 g/(L·d);0.246 g/(L·d),0.319 g/(L·d)和0.198 g/(L·d),0.229 g/(L·d)。这说明两种微藻在低氮胁迫下都能够获得较高的油脂产率。     

循环载体生物膜SBR反应器处理生活污水实验研究

采用中试规模,利用循环栽体生物膜SBR反应器处理某高校生活污水,实验结果表明:在反应时间4小时,容积负荷1.24～1.48kg CODm-3·d-1,转笼转速2min/r时,系统时COD、SS、NH3-N、TN、TP去除率分别达到90.4%、89.4%、87.5%、75.3%、83.2%,出水COD、SS、NH3-N、TN、TP分别为33mg/L、13.5 mg/L、7.6 mg/L、13.5 mg/L、0.55 mg/L.     

营养条件对Chlorella vulgaris生长的影响

以Chlorella vulgaris为研究对象,考察了培养基和有机碳源的影响.结果表明:在不同的营养方式中,混养的细胞密度和比生长速率最大,均超过自养和异养之和;改变培养液中的有机碳源种类,C.vulgaris的细胞密度最大分别达到2.92g/L(葡萄糖)、1.62g/L(乙酸钠)和1.05g/L(乙醇),且以葡萄糖为碳源时的比生长速率最大;当葡萄糖浓度从5g/L增加到30g/L时,C.vulgaris的比生长速率由0.0248h-1降低至0.0186h-1,不过在培养晚期,C.vulgaris在10g/L葡萄糖时的细胞密度超过5g/L葡萄糖时的密度;当以10g/L葡萄糖作为C.vulgaris混养的有机碳源时,BG1l培养基的细胞密度和比生长速率最大,分别达到3.41g/L和0.0257h -1,而在Basal培养基中,C.vulgaris 培养液较稳定,藻细胞始终处于悬浮的状态,其细胞密度和比生长速率分别为3.25g/L和0.0204h -1.     

联合反应器处理精对苯二甲酸废水的研究

本实验研究精对苯二甲酸(PTA)废水的最佳处理方法,试验研究表明厌氧HRT设定为18h,温度为37℃条件下联合反应器处理效果最佳.此时,UASB出水COD、TA、Pt酸、BA浓度分别为为450mg/L、15mg/L、40mg/L、1.0mg/L,SBR出水COD、TA、Pt酸、BA浓度分别为为25mg/L、0.5mg/L、25mg/L和0,去除率达90％以上,均达到国家排放标准.     

二株假单胞菌降解生物质气化洗焦废水COD的特性研究

为了使生物质气化中产生的洗焦废水得到循-环使用，首先用木屑、活性炭过滤预处理，滤液用菌种Pseudomonas SP1和Pseudomonas SP2进行进一步好氧降解。结果表明，COD浓度小于1800mg／L，采用两种菌降解颗粒活性炭过滤后的洗焦废水，均达到了理想的降解效果。SP1和SP2的COD去除率分别为73．2％和82．9％，SP2的降解效果明显好于SP1。当SP1和SP2等量混合降解颗粒活性炭过滤后的洗焦废水时，COD去除率达到98．1％。然后用生物膜反应器处理未经过滤预处理的生物质气化洗焦废水，经挂膜和增菌后，反应器可得到稳定和高效的运转，进水浓度1800mg／L，水滞留期保持在36h，洗焦废水的COD去除率为89％，苯、萘、酚、蒽、喹啉和异喹啉的去除率达到了理想的效果。     

Lipid production in mixotrophic cultivation of Chlorella vulgaris in a mixture of primary and secondary municipal wastewater

Microalgae's biomass productivity and oil content depend heavily on the method of its cultivation. In this study, nutrient removal from municipal wastewater by Chlorella vulgaris in batch culture was investigated. Carbon dioxide was supplied from sodium hydrogen carbonate. Effect of parameters including light intensity, sodium hydrogen carbonate concentration, and daily illumination time on the productivity of biomass and lipid was investigated. Lipid and biomass production of C. vulgaris increased at higher concentration of sodium hydrogen carbonate concentration and higher light intensity until a certain value and then decreased, but longer daily illumination time, increased both biomass and lipid productivity. Cultivation of C. vulgairs in mixotrophic mode was also studied in a mixture of primary and secondary wastewater with different ratios (25, 50 and 75 volume percent of the primary wastewater). It was observed that using 25% of the primary wastewater results in 100% COD removal, 100% ammonium removal and 82% nitrate elimination. Biomass productivity and lipid productivity of C. vulgaris in a mixture of primary (25%) and secondary wastewater were 138.76 mg/L/d and 45.49 mg/L/d, respectively.     

Comparison of dairy wastewater and synthetic medium for biofuels production by microalgae cultivation

This study is concerned with comparing raw dairy wastewater (DWW) with blue-green medium (BG11 medium) for biofuel production. Three microalgae strains (Chlorella sp., Scenedesmus sp., and Chlorella zofingiensis) were cultured in tubular bubble column photobioreactors with two media separately. After 8 days of cultivation, DWW was demonstrated to be more suitable medium for microalgae biomass and lipid production than BG11 medium. The biomass and lipid produced within wastewater provided suitable feedstocks for anaerobic digestion and biodiesel conversion. Nutrients in wastewater were efficiently removed (>90% total nitrogen removal, approximately 100% ammonia removal, and >85% total phosphorus removal) during this process.     

Simultaneous biohydrogen production and starch wastewater treatment in an acidogenic expanded granular sludge bed reactor by mixed culture for long-term operation

The biofilm-based expanded granular sludge bed (EGSB) reactor was developed to treat starch-containing wastewater and simultaneously recovery hydrogen by mixed microbial culture. Granular activated carbon (GAC) was used as the support media. Operating at the temperature of 30 °C for over 400 days (data not shown), the EGSB reactor presented high efficiency in hydrogen production and COD removal ability. The maximum hydrogen production rate (HPR) was found to be 1.64 L/L.d under the organic loading rate (OLR) of 1.0 g-starch/L.d, pH of 4.42 and HRT of 4 h. The hydrogen yield (HY) peaked at 0.11 L/g-COD, under the OLR of 0.5 g-starch/L.d, pH of 3.95 and HRT of 8 h. Hydrogen volume content was estimated to be 35–65% of the total biogas. The average COD removal rate was 31.1% under the OLR of 0.125 g-starch/L.d and HRT of 24 h. The main dissolved fermentation products were ethanol, acetate and butyrate. The average attached biofilm concentration was estimated to be 8.26 g/L, which favored hydrogen production and COD removal. It is speculated that the low pH operation in the present system would contribute significantly to lower the cost of alkaline amount required for pH control in the continuous operation, especially in the scale-up biohydrogen producing system. A model, built on the back propagation neural network (BPNN) theory and linear regression techniques, was developed for the simulation of EGSB system performance in the biodegradation of starch synthesis-based wastewater and simultaneous hydrogen production. The model well fitted the laboratory data, and could well simulate the removal of COD and the production of hydrogen in the EGSB reactor.     

Effect of hydraulic retention time on biohydrogen production from palm oil mill effluent in anaerobic sequencing batch reactor

The feasibility of hydrogen generation from palm oil mill effluent (POME), a high strength wastewater with high solid content, was evaluated in an anaerobic sequencing batch reactor (ASBR) using enriched mixed microflora, under mesophilic digestion process at 37 °C. Four different hydraulic retention times (HRT), ranging from 96 h to 36 h at constant cycle length of 24 h and various organic loading rate (OLR) concentrations were tested to evaluate hydrogen productivity and operational stability of ASBR. The results showed higher system efficiency was achieved at HRT of 72 h with maximum hydrogen production rate of 6.7 LH₂/L/d and hydrogen yield of 0.34 LH₂/g COD_feeding, while in longer and shorter HRTs, hydrogen productivity decreased. Organic matter removal efficiency was affected by HRT; accordingly, total and soluble COD removal reached more than 37% and 50%, respectively. Solid retention time (SRT) of 4-19 days was achieved at these wide ranges of HRTs. Butyrate was found to be the dominant metabolite in all HRTs. Low concentration of volatile fatty acid (VFA) confirmed the state of stability and efficiency of sequential batch mode operation was achieved in ASBR. Results also suggest that ASBR has the potential to offer high digestion rate and good stability of operation for POME treatment.     

Effect of hydraulic retention time on hydrogen production and chemical oxygen demand removal from tapioca wastewater using anaerobic mixed cultures in anaerobic baffled reactor (ABR)

This study evaluated hydrogen production and chemical oxygen demand removal (COD removal) from tapioca wastewater using anaerobic mixed cultures in anaerobic baffled reactor (ABR). The ABR was conducted based on the optimum condition obtained from the batch experiment, i.e. 2.25 g/L of FeSO₄ and initial pH of 9.0. The effects of the varying hydraulic retention times (HRT: 24, 18, 12, 6 and 3 h) on hydrogen production and COD removal in a continuous ABR were operated at room temperature (32.3 ± 1.5 °C). Hydrogen production rate (HPR) increased with a reduction in HRT i.e. from 164.45 ± 4.14 mL H₂/L.d (24 h HRT) to 883.19 ± 7.89 mL H₂/L.d (6 h HRT) then decreased to 748.54 ± 13.84 mL H₂/L.d (3 h HRT). COD removal increased with reduction in HRT i.e. from 14.02 ± 0.58% (24 h HRT) to 29.30 ± 0.84% (6 h HRT) then decreased to 21.97 ± 0.94% (3 h HRT). HRT of 6 h was the optimum condition for ABR operation as indicated.     

Biomass and lipid production of marine microalgae using municipal wastewater and high concentration of CO2

In order to reduce the cost of the production of microalgae for biodiesel, the feasibility of using the mixture of seawater and municipal wastewater as culture medium and CO₂ from flue gas for the cultivation of marine microalgae was investigated in this study. Effects of different ratios of municipal wastewater and 15% CO₂ aeration on the growth of Nannochloropsis sp. were examined, and lipid accumulation of microalgae was also studied under nitrogen starvation and high light. It was found that optimal growth of microalgae occurred in 50% municipal wastewater, and the growth was further significantly enhanced by aeration with 15% CO₂. When Nannochloropsis sp. cells were transferred from the first growth phase to the second lipid accumulation phase under the combination of nitrogen deprivation and high light, both biomass and lipid production of Nannochloropsis sp. were significantly increased. After 12 days of the second-phase cultivation, the biomass concentration and total lipid content increased from 0.71 to 2.23 g L⁻¹ and 33.8–59.9%, respectively. This study suggests that it is possible to utilize municipal wastewater to replace nutrients in seawater medium and use flue gas to provide CO₂ in the cultivation of oil-bearing marine microalgae for biodiesel.     

纤维藻培养及制备生物柴油的研究

探讨了纤维藻(Ankistudesmus sp)的低成本培养模式,考察了氮源和碳源以及反应器形式对纤维藻生物量、油脂积累以及油脂组成的影响。户外培养纤维藻在氮饥饿条件下油脂产率较高;通过槽式反应器和管式反应器的比较发现:槽式反应器更适合微藻的大规模培养;混养培养时能显著增加纤维藻的生物量和油脂含量,最佳添加条件下藻的生物量和油脂含量分别高达1.64 g/L和15.9%,1.41 g/L和11.9%。藻油经酸催化甲酯化制备生物柴油,经气相色谱分析,藻油主要成分为棕榈酸、油酸和亚油酸。氮缺陷、流加葡萄糖培养得到的纤维藻油含有25.32%的棕榈酸、44.74%的油酸,其制备得到的生物柴油具有更好的氧化稳定性和低温流动性。     

Statistical optimization of operating parameters of microbial electrolysis cell treating dairy industry wastewater using quadratic model to enhance energy generation

The performance of Microbial electrolysis cell (MEC) is affected by several operating conditions. Therefore, in the present study, an optimization study was done to determine the working efficiency of MEC in terms of COD (chemical oxygen demand) removal, hydrogen and current generation. Optimization was carried out using a quadratic mathematical model of response surface methodology (RSM). Thirteen sets of experimental runs were performed to optimize the applied voltage and hydraulic retention time (HRT) of single chambered batch fed MEC operated with dairy industry wastewater. The operating conditions (i.e) an applied voltage of 0.8 V and HRT of 2 days that showed a maximum COD removal response was chosen for further studies. The MEC operated at optimized condition (HRT- 2 days and applied voltage- 0.8 V) showed a COD removal efficiency of 95 ± 2%, hydrogen generation of 32 ± 5 mL/L/d, Power density of 152 mW/cm² and current generation of 19 mA. The results of the study implied that RSM, with its high degree of accuracy can be a reliable tool for optimizing the process of wastewater treatment. Also, dairy industry wastewater can be considered to be a potential source to generate hydrogen and energy through MEC at short HRT.     

Direct fermentation of Laminaria japonica for biohydrogen production by anaerobic mixed cultures

A few studies have been made on fermentative hydrogen production from marine algae, despite of their advantages compared with other biomass substrates. In this study, fermentative hydrogen production from Laminaria japonica (one brown algae species) was investigated under mesophilic condition (35 ± 1 °C) without any pretreatment method. A feasibility test was first conducted through a series of batch cultivations, and 0.92 mol H₂/mol hexose_added, or 71.4 ml H₂/g TS of hydrogen yield was achieved at a substrate concentration of 20 g COD/L (based on carbohydrate), initial pH of 7.5, and cultivation pH of 5.5. Continuous operation for a period of 80 days was then carried out using anaerobic sequencing batch reactor (ASBR) with a hydraulic retention time (HRT) of 6 days. After operation for approximately 30 days, a stable hydrogen yield of 0.79 ± 0.03 mol H₂/mol hexose_added was obtained. To optimize bioenergy recovery from L. japonica, an up-flow anaerobic sludge blanket reactor (UASBr) was applied to treat hydrogen fermentation effluent (HFE) for methane production. A maximum methane yield of 309 ± 12 ml CH₄/g COD was achieved during the 90 days operation period, where the organic loading rate (OLR) was 3.5 g COD/L/d.