不同粒径生物质灰渣填料净化生活污水的试验研究

以生物质灰渣为研究对象,采用室内土柱淋溶模拟法,研究了不同粒径组合的生物质灰渣对生活污水中化学需氧量(COD)、总氮(TN)、总磷(TP)、氨氮(NH+4-N)的去除效果。结果表明:(1)COD的去除效果随粒径的增加而增加,L1处理(0.25~0.5mm粒径组合)对COD的去除效果最好,去除率在79.2%以上;(2)试验运行期间,出水TN浓度随进水次数的增加而增加,前期各处理均保持较高的TN去除率,整个试验过程L6处理对TN的去除效果最明显;(3)出水TP浓度随着试验的进行逐渐升高,在整个试验过程中,出水TP浓度表现为L6L5L2L3L1L4处理,其中L4处理对TP的去除效果稳定,平均去除率达48.7%,小粒径填料对TP的去除效果较差;(4)各处理均能有效的去除氨氮,去除率均在90%以上,但较大粒径的填料对氨氮的去除效果更好。总体而言,小粒径生物质灰渣对TN有较好的去除效果,大粒径填料L1处理对COD和氨氮去除效果较好,均一中粒径的L4处理对TP的去除效果较好。     

不同水力负荷下生物质灰渣填料系统处理生活污水的研究

以生物质灰渣为填充材料,采用室内土柱淋溶模拟试验方法,研究了5种水力负荷下生物质灰渣填料对生活污水的处理效果。结果表明:在试验初期,系统内部微生物的活性弱,导致系统出水COD和TN浓度较高。随着进水次数的增加,各指标出水浓度逐渐降低,到后期,随着吸附消纳的饱和,TN、TP和铵态氮浓度表现出逐渐升高的趋势。在整个系统运行期间,5种水力负荷下生物质灰渣对COD的平均去除率分别为39%,62.7%,60.7%,59.1%,60.2%;TN平均去除率分别为34.3%,84%,73.8%,67.4%,40.4%;5种水力负荷下TP出水浓度最高为1.248mg/L,平均出水浓度在0.149~0.496mg/L之间,TP平均去除率为83%~97.6%,去除效果较好;生物质灰渣对铵态氮的去除效果最好,平均去除率高达98%以上。试验后期,在W5处理的高水力负荷运行中,装置出现堵塞现象,系统不能正常运行。总体而言,水力负荷为7.5~10cm3/(cm2·d)时,生物质灰渣的处理效果最好。     

不同生物质灰渣填充密度下处理生活污水的效果研究

以生物质灰渣为研究对象,采用土柱淋溶模拟法,研究在不同生物质灰渣填充密度R1(0.3g/cm~3)、R2(0.35g/cm~3)、R3(0.4g/cm~3)下,生物质灰渣对生活污水中主要污染物即化学需氧量(COD)、总氮(TN)、氨氮(NH_3—N)、总磷(TP)的去除效果。结果表明:生物质灰渣对COD的去除率随着填料密度的增加先升高后降低,表现为R2(59.1%)R1(58.0%)R3(44.4%),其中R2处理效果明显优于R1和R3处理;R1、R2、R3对TN的去除率分别为84.8%,43.3%,26.1%,而对污水中氨氮的去除效果良好,去除率均达到97%以上;对污水中TP而言,3种密度下平均出水TP浓度分别为0.406,0.249,0.406mg/L,平均去除率大小为分别为R2(91.3%)R1(85.8%)R3(85.6%),去除效果较好。在试验后期由于被吸附的磷被释放出来,故对污水中TP的去除效果并不明显,但R2处理效果仍优于其他2种处理。总体而言,生物质灰渣可有效去除污水中COD、TN、NH_3—N和TP,其中NH_3—N和TP的除去率均在85%以上,生物质灰渣填料密度为0.35g/cm~3的处理效果最好。     

抽屉式生物滤器净化效果

以浸没式生物滤器为对照,研究了抽屉式生物滤器对循环养殖水的净化效果和不同氧含量对NH4-N、NO2-N、化学需氧量（COD）、异养菌、弧菌去除率的影响。结果表明：抽屉式生物滤器单位体积对NH4-N、NO2-N、COD、异养菌、弧菌的去除率均显著高于浸没式生物滤器,前者分别是后者的2.68、7.37、3.33、24.87、46.67倍;高溶氧对生物滤器NH4-N、NO2-N、COD、异养菌的去除率显著高于低溶氧条件下的去除率,高溶氧可维持养殖系统较低的NH4-N、NO2-N、COD、弧菌数量。在抽屉式循环系统预计最大养殖密度下,养鱼池水质良好,NH4-N质量浓度＜0.2 mg/L,NO2-N质量浓度＜0.4 mg/L,鱼成活率高于98%。该试验表明：抽屉式生物滤器是一种易冲洗、占地面积小、净化效率高的生物滤器;高溶氧能提高鱼类生长率、生物滤器净化率和抑制弧菌的生长。     

球墨铸铁屑处理含铬废水的试验研究

用球墨铸铁屑处理含铬废水的试验研究的结果表明:当含铬废水Cr⁶⁺含量为4.5mg/L时,其Cr⁶⁺去除率>90%,出水Cr⁶⁺含量≤0.42mg/L,小于国家标准的0.5mg/L;当温度为21℃、铁屑粒度为1.2～2.0mm时的最佳工艺方案为:进水pH值为2.0～2.4,出水沉淀时pH值为8.0～9.0,接触时间为15～21min。     

提高猪场沼液净化处理效果的氨吹脱控制参数

针对畜禽养殖场沼气工程沼液氨氮浓度高,碳氮比不足,直接采用传统生化污水处理法效果不佳的问题,该文对氨吹脱工艺降低猪场沼液氨氮浓度参数进行了试验研究,探索了不同初始氨氮浓度、pH值、气液比、温度等参数对氨氮去除的效果,并进一步研究了Ca(OH)2的混凝作用。结果表明:初始氨氮质量浓度分别为500和900mg/L时,氨氮去除率无显著差异。在初始氨氮质量浓度为900mg/L,pH值为10.5,气液比(流量比)2000,沼液温度30℃的运行条件下,氨氮去除率较高为81.84%。在Ca(OH)2投加量为5.0g/L条件下,混凝沉淀效果较好,化学需氧量(COD)、总磷(TP)和PO43-去除率分别为30.13%、97.44%和98.76%,但总硬度提高了106%。该文研究结果为开发沼液深度处理工艺提供了数据。     

电极-SBBR对集中型沼液的脱氮除铜研究

为了处理集中型沼液中过高的氨氮和由饲料添加剂带入的铜,将电极生物膜法与序批式生物膜反应器(SBBR)工艺的优势进行互补,构建电极-SBBR耦合新工艺,以同时去除氮与铜。通过实验室配水与沼液试验,探讨了电极-SBBR体系同步脱氮除铜的工艺参数及其效果。结果表明,集中型沼液电极-SBBR体系的操作工序为:进水→厌氧→曝气→缺氧/厌氧→出水→闲置,运行参数为:水力停留时间7.0h,厌氧0.5h、曝气4.0h、缺氧/厌氧2.5h;电流30～60mA,溶解氧(DO)4.0～5.0mg/L,碳氮比(C/N)>10.0。电极-SBBR体系对沼液中全氮(TN)、Cu2+、化学耗氧量(COD)的去除率分别达到45.79%、86.53%和84.86%,可以作为沼液脱氮除铜的新工艺。     

运行条件对膜生物反应器处理猪场厌氧消化液效果的影响

为探讨膜生物反应器处理猪场厌氧消化液效果和合适的操作条件,该文分别选择了三种不同的水力停留时间(HRT)、间歇曝气区曝/停比和膜出水抽/停比,根据三水平正交表安排试验.结果表明:进水COD为1240～1830 mg/L,BOD5为154～420 mg/L时,出水COD(化学需氧量)为208～811 mg/L,BOD5(生化需氧量)为7～13 mg/L,COD和BOD5去除率分别达到51.7%～83.2%和93.0%～97.1%.试验所选因素中HRT对COD去除效果的影响最大,HRT=24h与20 h、15 h时的COD去除率差异显著(P<0.05),分别平均提高7.3%和13.4%.当水温在24～28℃时NH4 -N去除效果随水温的升高明显提高,但水温上升到28.0～35.8℃时,NH4M; >-N去除效果随水温变化不大.     

惰性填料种类对猪场沼液氨吹脱效果的影响

氨吹脱作为猪场沼液的预处理方法,其处理效果受填料等多种因素的影响。分别采用空心多面球、鲍尔环和流化床填料在pH值10.5,气液比2000,温度30℃的条件下吹脱猪场沼液,结果表明:空心多面球和流化床对沼液氨氮(ammonia nitrogen,NH4+-N)的平均去除率显著高于鲍尔环填料(P0.05),吹脱2 h,氨氮的平均去除率分别为80.7%、59.0%和77.4%。投加NaOH使沼液化学需氧量(chemicaloxygendemand,COD)因压缩双电层和混凝而降低,总固体(totalsolid,TS)和挥发性固体(volatilesolid,VS)因OH-对微生物结构的破坏和大分子物质的水解而增加。吹脱过程使COD部分提高,而TS和VS有所降低。3种填料的性能参数差异导致吹脱后沼液COD平均去除率的变化和VS的平均去除率不同,但不存在显著差异(P0.05),流化床填料对TS的平均去除率显著高于空心多面球(P0.05)。选定空心多面球吹脱20 L沼液2 h,1 L的1 mol/L硫酸吸收液对吹脱尾气中氨气的平均吸收率为35.8%,兼顾吸收效果和经济性。     

小球藻对不同沼液添加量培养液的适应性及净化效果

以成分相对简单、未经灭菌的秸秆厌氧发酵后沼液和BG11培养基的混合液为培养液,以FACHB-5号和FACHB-8号小球藻为藻种,利用人工气候培养箱,在微藻培养温度为(26±1)℃,光照强度为4 000 lx,24 h连续光照,通气量为1.5 L/min,沼液添加比例为20%、30%和40%的条件下,系统研究秸秆厌氧发酵后沼液直接用于微藻养殖对微藻系统的影响。结果表明:试验采用的小球藻FACHB-8号藻种和FACHB-5号藻种均能较好地适应化学需氧量COD含量相对较高的秸秆厌氧发酵后沼液,但FACHB-8号藻种与FACHB-5号藻种相比对沼液的适应时间更短,适应能力更强;FACHB-8号藻种和FACHB-5号藻种均能较好的利用和转化沼液中的有机污染物,各试验组的COD去除率均大于90%,总氮去除率均大于96%,总磷去除率均大于92%。该研究可为沼液直接用于微藻养殖提供参考。     

Chemical Oxygen Demand (COD) Reduction in Domestic Wastewater by Fly Ash and Brick Kiln Ash

The potential of fly ash, brick kiln ash and commercial activated carbon is determined for the reduction of chemical oxygen demand (COD) from domestic wastewater. Laboratory experiments are conducted for investigating the effect of treatment time, adsorbent dose, pH of the media, initial COD concentration, agitation speed and particle size of adsorbents on the COD reduction from the domestic wastewater. Starting with an initial COD concentration of 1080 mg/l the maximum COD reduction achieved for fly ash was 87.84%, brick kiln ash was 83.22% and commercial activated carbon was 99.35 %. These values were achieved when the wastewater was treated with activated carbon for 180 min, fly ash 250 min and brick kiln ash 300 min and the adsorbent dose was kept respectively at 40 g/l, 60 g/l and 45 g/l for activated carbon, fly ash and brick kiln ash. Agitation speed was kept constant at 600 rpm and the pH was maintained at 2 for activated carbon and fly ash and 5 for brick kiln ash. The maximum percent reduction is for 0.053 mm or smaller size of the particles. Though the adsorption capacity of the ash for reducing the COD is lower than that of the commercial activated carbon, the low material cost can make it an attractive option for the treatment of domestic wastewater.     

Effects of Ground Corn Particle Size on Ethanol Yield and Thin Stillage Soluble Solids

The effects of ground corn particle size on ethanol yield and soluble solids in thin stillage was evaluated using a 2‐L laboratory dry‐grind procedure. The procedure was optimized for grinding, liquefaction, sacchari‐fication, and fermentation parameters. The optimized procedure was reproducible with a coefficient of variation of 3.6% in ethanol yield. Five particle size distributions of ground corn were obtained using a cross‐beater mill equipped with five screens (0.5, 2, 3, 4, and 5 mm). Particle size had an effect on ethanol yield and on soluble solids concentration in thin stillage. The highest ethanol yield of 12.6 mL/100 mL of beer was achieved using a 0.5‐mm screen in the cross‐beater mill. Treatment using the 0.5‐mm mill screen resulted in soluble solids concentration of 25.1 g/L and was higher than soluble solids concentrations obtained with other screens. No differences in soluble solid concentrations were observed in samples of thin stillage obtained from 2, 3, 4, and 5‐mm screens which had a mean yield of 16.2 g/L. By optimizing particle size for maximum ethanol yield and minimum solids in thin stillage, dry‐grind corn plants could realize reduced capital and operating costs.     

江苏省大中型沼气工程调查及沼液生物学特性研究

近年来,中国大中型沼气工程发展迅速,然而有关沼气工程运行情况的研究甚少。为探索沼气工程运行中存在的问题,该文对江苏省21家畜禽养殖场大中型沼气工程进行了实地调查,并采集发酵料液以及出料样品,分析了进出料液COD(化学需氧量)质量浓度、沼液产气潜力、粪大肠菌群数等指标。结果表明:江苏省沼气工程设计施工规范,配套设施较完备,但运行效率低,沼气、沼液处理或利用能力低。大多数沼气工程以处理养殖废水为主,发酵料液固体质量分数<3%,62%的出料沼液的COD质量浓度达到5000mg/L以上;沼液残余产气潜力较大,在35℃条件下,有12家沼气工程的沼液残余产甲烷量达100mL/L以上。沼气发酵处理可以显著降低粪大肠菌群含量,平均可减少92.9%,但厌氧消化后的沼液中仍含有较高浓度粪大肠菌群,不能达到无害化要求。该调查结果可为畜禽养殖场沼气工程的健康稳定运行与管理提供科学依据。     

Stabilization of Preliminary Anaerobically Digested Slurry in Post-Storage: Dynamics of Chemical Characteristics and Hygienic Quality

Dynamics of chemical characteristics and hygienic quality, particularly nutrients, heavy metals, and bacterial pathogens, were investigated along the storage of anaerobically digested slurry derived from chicken and pig manure. The average total solid (TS) content decreased by 3.6 and 24.1%, while soluble chemical oxygen demand (SCOD) decreased by 23.7 and 31.4%, in chicken manure- and pig manure-digested slurries storage, respectively. A rapid increase in NH₄ ⁺-N concentration from 1600 to 4800 mg/L in chicken manure-digested slurry and from 1200 to 1700 mg/L in pig manure-digested slurry was noted, particularly during the first 10 days of storage. A positive correlation between TS and content of heavy metals (Cu, Zn, Cr, and Pb) in the digested slurry was clearly shown. These metals are mainly associated with suspended particles and tend to be settled in the bottom during the storage process. Increasing attention should be paid to the land application of these bottom-settled digestates with higher TS content. The number of total coliforms and Escherichia coli in the both digested slurries decreased continuously during the whole storage period. The higher reduction rate observed during the storage of chicken manure-digested slurry may be due to the higher content of NH₄ ⁺-N, which may cause the inhibition of gram-negative bacteria. The results of this study provides a better understanding of the storage process of anaerobically digested slurry, which could benefit the digested slurry further utilization as agriculture fertilizer.     

汽爆预处理青玉米秸秆厌氧发酵特性

为了研究青玉米秸秆未汽爆和汽爆预处理后厌氧发酵产沼气特性,该文采用汽爆压力为2.5MPa,保压时间为90s,加入质量分数为30%的沼液,未气爆青玉米秸秆的TS(总固体物)质量分数为6%,汽爆预处理青玉米秸秆厌氧发酵的TS质量分数分别为1%、2%、3%、4%、6%、8%、10%和15%,考察了厌氧发酵过程中pH值和产气量随时间和TS质量分数的变化。结果表明:未汽爆秸秆在TS质量分数为6%时能够顺利厌氧发酵,但汽爆秸秆厌氧发酵液极易酸化,且无法调节,适宜的TS质量分数最大为4%;未汽爆秸秆挥发性固体产气率为214.6mL/g,汽爆秸秆在TS质量分数为3%时产气率最大,为334.8mL/g,比未处理秸秆提高了56%;未汽爆秸秆的产气速率为3.3mL/(g·d),汽爆秸秆产气速率随TS质量分数增大而减小,在TS质量分数为1%时最大,为14.8mL/(g·d)。青玉米秸秆经汽爆预处理后其厌氧发酵产沼气的产气率和产气速率大大提高,可以节约发酵时间,缩短发酵周期,有利于秸秆能源化利用的工业化生产。     

Effects of digestate from anaerobically digested cattle slurry and plant materials on soil microbial community and emission of CO2 and N2O

Anaerobic digestion of animal manure and crop residues may be employed to produce biogas as a climate-neutral source of energy and to recycle plant nutrients as fertilizers. However, especially organic farmers are concerned that fertilizing with the digestates may impact the soil microbiota and fertility because they contain more mineral nitrogen (N) and less organic carbon (C) than the non-digested input materials (e.g. raw animal slurry or fresh plant residues). Hence, an incubation study was performed where (1) water, (2) raw cattle slurry, (3) anaerobically digested cattle slurry/maize, (4) anaerobically digested cattle slurry/grass-clover, or (5) fresh grass-clover was applied to soil at arable realistic rates. Experimental unites were sequentially sampled destructively after 1, 3 and 9 days of incubation and the soil assayed for content of mineral N, available organic C, emission of CO₂ and N₂O, microbial phospholipid fatty acids (biomass and community composition) and catabolic response profiling (functional diversity). Fertilizing with the anaerobically digested materials increased the soil concentration of NO₃⁻ ca. 30–40% compared to when raw cattle slurry was applied. Grass-clover contributed with four times more readily degradable organic C than the other materials, causing an increased microbial biomass which depleted the soil for mineral N and probably also O₂. Consequently, grass-clover also caused a ∼10 times increase in emissions of CO₂ and N₂O greenhouse gasses compared to any of the other treatments during the 9 days. Regarding microbial community composition, grass-clover induced the largest changes in microbial diversity measures compared to the controls, where raw cattle slurry and the two anaerobically digested materials (cattle slurry/maize, cattle slurry/grass-clover) only induced minor and transient changes.     

坡面覆沙后侵蚀泥沙颗粒分选特性

侵蚀泥沙颗粒大小的分布在一定程度上影响着侵蚀泥沙的搬运和沉积,了解侵蚀泥沙的分选作用将有助于解释泥沙的侵蚀和沉积过程。该文以覆沙坡面为研究对象,采用室内模拟降雨的方法,选取坡度12°、雨强1.5 mm/min的黄土坡面上分别覆盖0.5、1.0、1.5 cm的沙层进行试验。结果表明:坡面覆沙后,坡面粗颗粒物质大部分在产流开始0~10 min内便被冲刷带走;侵蚀泥沙颗粒主要以粉粒为主;坡面覆沙后,在细沟间侵蚀阶段,径流优先搬运大于0.054 mm的颗粒,在细沟侵蚀阶段和细沟侵蚀及细沟间侵蚀的组合阶段,径流搬运的泥沙颗粒以小于0.054 mm的颗粒为主;同时,在产流前期(0~10 min)侵蚀泥沙颗粒主要以大于0.054 mm的颗粒为主;而在产流后期(10 min以后)侵蚀泥沙则主要以小于0.054 mm的颗粒为主。坡面覆沙后,黏粒以团聚体的形式存在,粉粒以单粒的形式存在,而沙粒以细颗粒聚集体的形式存在。该文为进一步研究泥沙沉积后风蚀对水蚀的影响提供数据支撑。     

泥沙粒径与含沙量对迷宫流道滴头堵塞的影响

为探明泥沙粒径与含沙量对内镶片式斜齿形迷宫流道滴头的堵塞过程和原因,采用筛分法,分选出6个小于0.1 mm的粒径段,配制成不同含沙量的浑水,在恒压条件下,采用周期性间歇灌水试验观测流量变化,通过电镜扫描法观测堵塞泥沙结构。试验结果表明:粒径为0.075≤D0.1 mm和0.03≤D0.038 mm的泥沙易引起滴头堵塞;粒径为0.038≤D0.05和D0.02 mm的泥沙较难引起堵塞,且含沙量变化对堵塞的影响较小;粒径0.02≤D0.03 mm和0.05≤D0.075 mm的堵塞情况介于上述两者之间。当含沙量为1.2~1.3 g/L时,是最易引起堵塞的临界含沙量。当0.038≤D0.1 mm时,泥沙在流道内不易形成团聚体,造成滴头堵塞的原因是泥沙沉降、堆积;当D0.038 mm时,泥沙易在流道中凝结成大的团聚体,是造成滴头堵塞的主要原因。     

基于蜂窝结构的仿生立式环模生物质颗粒机设计与试验

针对传统生物质颗粒环模成型机生产成型效率低、环模失效严重等问题，基于仿生蜂窝状有序多模孔结构，该研究提出了一种立式环模生物质颗粒成型机仿生设计方法。对蜂窝单体几何模孔结构进行图像处理，对蜂窝相邻模孔边缘轮廓拐点坐标进行提取，并获取模孔网格坐标，构建环模-压辊-物料耦合作用受力模型，以物料摄取量、挤压力为设计目标，对颗粒成型机仿生环模、模孔、压辊等参数进行设计。样机通过三压辊与仿生环模孔之间摩擦作用，实现对成型区域内物料的挤压成型，从而形成致密的生物质颗粒。温室条件下以颗粒度为2～4 mm的玉米秸秆为物料，物料含水率为12%、压辊主轴转速为100 r/min，结果表明：在相同转速下，优化后的仿生立式环模生物质颗粒成型机较传统环模成型机吨料能耗降低10.08%，生产的成型颗粒密度大于等于1.32 g/cm³，抗跌碎性指数为99.4%，样机能耗为40.46 kW·h/t，该研究各项指标均达到了相关标准的要求且高于传统生物质颗粒机。     

鸡粪高固体浓度进料厌氧消化连续运行性能

以鸡粪为处理对象,进料总固体（Total Solids, TS）浓度控制在15%,进行鸡粪高固体浓度进料厌氧消化试验,在水力停留时间（Hydraulic?Retention?Time, HRT）为 60 d的条件下,连续运行155 d考察发酵性能。试验结果表明,在有机负荷（Organic Load Rate, OLR）为1.5 g/(L·d)（以Volatile Solids, VS计算）和氨氮（Total Ammonia Nitrogen, TAN）浓度7.5 g/L的条件下,甲烷产率达到326 mL/g,总挥发性脂肪酸（Total Volatile Fatty Acids, TVFA）浓度在0.5 g/L左右, pH值在8.3以上,实现了低有机酸残留的鸡粪高固体浓度进料厌氧消化的稳定运行。鸡粪的水解率、酸化率以及产甲烷率分别为61%、47%和47%。厌氧污泥的比产甲烷活性（Specific Methanogenic Activity, SMA）为0.042 g/(g·d),显示有较好的代谢活性,利用一级动力学模型进行模拟,动力学常数为0.202 d-1,相关性系数为0.982。该研究验证了通过延长HRT适当降低OLR的方式,鸡粪高固体浓度进料厌氧消化可以耐受极高的氨氮浓度,为工程应用提供了可能性。