Leachate from market refuse and biomethanation study

The market place is considered to be an important centre of daily life of campus community. In India, as in Europe and the USA, other forms of shopping have emerged significantly and now predominate, for instance department stores and supermarkets. Though, it is suffered from poor waste management, but the place could be a potential source for obtaining non-conventional energy. The present study examined the quality of market waste management of the Indian Institute of Technology Campus along with the feasibility of biogas production from leachate generated in the waste. Solid wastes from different storage locations of the market place were collected and analyzed. The characteristics of solid wastes were found to be degradable in nature. The wastes, composed of 85% of vegetable origin, were placed in a container and water was added to to generate leachate. The self-purification efficiency of leachate was also studied in the Indian environment and compared with research findings in the USA under an identical moisture application rate. Leachate characterization was investigated both under saturated and submerged conditions. The treatability of leachate was studied in a laboratory-scale up-flow anaerobic filter with hollow burnt clay rings as packing media. It was observed that 4,000–6,000 mg/l would be the optimum range of inlet chemical oxygen demand (COD) concentration for leachate treatment because of the inhibitory effect of ammonia, sulphide, volatile fatty acids and toxic metals in high concentrations at higher strengths of leachate. The gas production rate was found to be at a maximum at 38°C and containing 70–75% methane. From experimental data, it was revealed that 83% COD was removed with input COD concentration of 5,475 mg/l at 2 days hydraulic retention time with biogas yield coefficients of 0.61. The present study also investigated the removal efficiency of chloride, ammonia, sulphide and nitrate.     

DO C/N对同步硝化反硝化影响的试验研究

在序批式活性污泥反应器(SBR)内,以模拟的城市污水为处理对象,研究DO、C/N等因素对同步硝化反硝化脱氮效率的影响。研究表明:采用连续曝气工艺,在进水COD=200mg/L,NH4+-N=30mg/L条件下,控制DO在0.5～1.5mg/L范围内时,出水TN浓度为1.98～6.3mg/L,TN的平均去除率在80%以上,最高去除率达到93.74%,并可推断出在反应系统内存在好氧反硝化菌;C/N在3.3～10之间时,C/N越高,出水NO3--N浓度越低,SND效果越好。     

溢流堰形态对水体营养盐及有机污染的影响

定期监测两种不同形态的溢流堰坝体上下点的溶解氧及水质变化,研究溢流堰形态对水体营养盐及有机污染的影响。结果表明:两种不同形态的溢流堰均可较好地提高水体的DO含量,且阶梯式溢流堰较斜面式溢流作用明显;高锰酸盐指数IMn、NH3-N、TP含量均减少,平均去除率阶梯式溢流堰均优于斜面式溢流堰。     

水循环周期对生态床内氮形态转化过程的影响

构建复合生态床修复北方景观水体,通过控制出水循环周期,研究不同循环速率下水体氮在系统内的转换及不同转换过程之间的关系,深入分析复合基质生态床修复景观水的过程及作用机理.结果表明,当循环周期为1 h和1.5 h时,溶解氧经首次循环由7提高至11左右,并始终保持较高水平;C/N由进水时4～6提高至出水时6～10,C/N的升高说明系统中N的相对去除率高于C,循环促进了氮及有机物的去除.出水循环提高了NH⁺₄-Ｎ、NO^-₂-Ｎ及TN的去除率, 且循环速率的提高使得硝化作用进行得更加迅速和彻底,补充了氮从系统中去除的好氧反硝化途径.当循环周期为1.5 h和1 h时,NH⁺₄-Ｎ与NO^-₂-Ｎ去除过程间的相关系数值分别为0.885 3和0.968 5;NO^-₂-Ｎ与TN去除过程间的相关系数随循环速率加快而增加,最高为0.942 4.当循环速率加快,NH⁺₄-Ｎ的氧化与NO^-₂-Ｎ的氧化2个过程间的传递更加迅速, 缩短了氮在系统中的转化途径,且循环速率越快,整个转化越迅速.     

微生物传感器快速测定水中BOD

采用220B型BOD快速测定仪,对标准样品、地表水、生活污水、工业废水中的BOD进行测定,与五日生化培养法进行了比对分析.结果表明：该方法检出限为0.032mg/L;加标回收率在85%～117%之间;相对误差＜6%,相对标准差＜9%,有较高的精密度、准确度;测定地表水、生活污水与五日生化培养法有较好的可比性,测定工业废水存在一定的局限.同时还阐述了微生物传感器快速测定法测定BOD与五日生化培养法,并对其优缺点做了分析比较.     

溶解氧对分段进水生物脱氮工艺的影响

采用分段进水生物脱氮工艺处理生活污水.设置0.9,0.6,0.4,0.3m³/h4组曝气量,相应的好氧区溶解氧(DO)浓度约为2.8,1.7,0.8,0.5mg/L左右.结果表明,在好氧区DO为0.5mg/L左右的低氧条件下,通过对系统进行适当的控制,可以取得较好的硝化效果,氨氮去除率可达98%以上.同时,由于低曝气量下混合液从好氧区到缺氧区携带的DO量减少,并且在好氧区发生了同步硝化反硝化作用,使得TN去除效果明显优于高曝气量的情况.另外,由于工艺结构的特点,分段进水生物脱氮系统可长期在低氧条件下运行,且污泥沉降性能良好.     

A2O 工艺中的污泥膨胀问题及恢复研究

采用52L 以厌氧/缺氧/好氧为污水处理工艺(A2O)的试验装置处理人工合成废水,研究了A2O 工艺中出现污泥膨胀的原因及控制措施.结果表明,系统在稳定状态下,好氧区DO平均浓度约为1.08mg/L 时,COD、NH4+-N、TN以及PO43--P 的平均去除率分别为86.8%、97.5%、86.5%和95.5%,但污泥的沉降性能受到很大影响,其SVI 从最初的130.1mL/g 升至265.8mL/g,并有继续上升的趋势,引起污泥膨胀.当好氧区DO 平均浓度提高至2.16mg/L 时,污泥的沉降性能得到部分改善,SVI 降至约200mL/g.在好氧区首端引入 15%的原水旁流,经过 30d 的运行,SVI 降低至100mL/g 左右,污泥膨胀得到恢复.说明好氧区偏低的有机负荷是引起污泥膨胀的主要原因,单纯提高好氧区的DO 浓度并不能有效控制污泥膨胀,控制A2O 中污泥膨胀的关键在于对有机负荷的合理分配.     

溶解氧对单级颗粒污泥自养脱氮系统影响的模拟

为了研究溶解氧对SBR单级颗粒污泥自养脱氮系统的影响,基于活性污泥ASM3模型和短程硝化-硝化-反硝化模型,将颗粒污泥传质过程与氨氧化菌（AOB）、厌氧氨氧化菌（AAOB）、亚硝酸盐氧化菌（NOB）、反硝化菌（DNF）的生长过程、好氧内源呼吸及缺氧内源呼吸过程等耦合,建立了单级自养脱氮颗粒污泥动力学模型,并对颗粒内部基质浓度分布进行预测.结果显示,当DO为0.4mg/L时,好氧区和缺氧区（厌氧区）的比例为0.4：1;当DO为0.6mg/L时,颗粒污泥好氧区与缺氧区（厌氧区）的比例为3：1.同时,根据基质反应速率方程,建立了颗粒污泥的单级自养脱氮系统动力学模型,对SBR系统运行效果进行预测,结果显示,DO为0.6mg/L时,氨氮反应完全,亚硝酸盐氮和硝酸盐氮在5mg/L以下,总氮去除率模拟值为89%左右,略低于实际测量脱氮率95%.     

生物活性炭对不同C/N比废水同步硝化反硝化脱氮效果的影响

以连续运行的生物活性炭(biological actived carbon,BAC)填料反应器为研究对象,与序批式活性污泥反应器(sequencing batch reactor,SBR)对比,考察了BAC的加入对不同C/N比废水同步硝化反硝化(simultaneous nitrification and denitrification,SND)脱氮效果的影响.在室温(15~27℃),初始溶解氧(dissolved oxygen,DO)质量浓度2~3 mg·L-1条件下,以甲醇做外加碳源,分别设置进水C/N比为3、5、8和10运行120个周期,比较两反应器的脱氮效果及稳定性.结果表明,C/N比由3依次升至5和8时BAC填料反应器脱氮效果优于SBR,TN平均去除率分别达44.88%、58.07%和66.64%.继续增大进水C/N至10,SBR发生污泥膨胀,而BAC反应器仍能保持63.65%的TN去除率.实验证明BAC在单一反应器内创造了多样的溶解氧环境,为SND创造了适宜的条件.BAC的加入减小了过量有机碳对硝化系统带来的影响,扩大了反应器的C/N比适用范围,增加了运行的稳定性,提高了有机物的脱氮容量,为高效脱氮提供了可能.     

基于DO-stat流加培养控制的L-异亮氨酸发酵条件优化

L-异亮氨酸(L-lie)产生菌代谢流的前期研究报道认为,较低的溶氧浓度有利于L-异亮氨酸的积累.为进一步提高L-异亮氨酸的产量,采用DO-stat流加培养控制方法,分别研究了溶氧浓度20%、30%、35%和40%下乳糖发酵短杆菌发酵液中葡萄糖浓度的变化以及L-异亮氨酸的合成情况.结果表明,当发酵罐中溶氧浓度控制在20...