利用沼液制备微生物絮凝剂及产絮条件优化

为降低微生物絮凝剂发酵成本,采用以牛粪和秸秆为底物的大型沼气发酵工程厌氧消化的沼液作为制取微生物絮凝剂的替代培养基,并优化了产絮菌F2-F6的发酵条件。结果表明,经预处理并添加5 g/L的K2HPO4、2 g/L的KH2PO4和2 g/L葡萄糖且灭菌后,絮凝菌可以利用其进行正常产絮。利用响应曲面法对发酵条件进行优化,得到絮凝菌利用沼液作为替代培养基进行发酵的最佳条件是:发酵温度为29.5℃、培养基初始pH值为7.5、接种量为8.5%、发酵时间为23 h,在最优发酵条件下絮凝率为87.13%。     

生物絮凝剂产生菌的鉴定及对EE2的去除效能

从活性污泥中筛选出一株高效生物絮凝剂产生菌J1,经鉴定该菌为克雷伯氏菌(Klebsiella sp.)。菌株J1的生物絮凝剂产率为2.15 g/L,絮凝率为90.83%。利用产絮菌J1发酵产生的生物絮凝剂MFX去除水中的17α-乙炔雌二醇(EE2),在絮凝剂投加量为8 mL、助凝剂投加量为1 mL、初始pH值为5、反应时间为1 h的最优条件下,对EE2的去除率可达90%;pH值对生物絮凝剂去除EE2的影响最大,其次为助凝剂投加量、絮凝时间和絮凝剂投加量;结合表面电荷及Zeta电位的变化情况,推测该絮凝过程以电中和作用为主。     

复合型微生物絮凝剂的开发

首次提出了复合型微生物絮凝剂这一概念，即采用廉价底物经过多株菌混合发酵后制得的微生物絮凝剂。发酵过程中采用的菌种取自活性污泥和土壤，分离筛选出的4株絮凝率较高的菌株经鉴定均为芽孢杆菌属。把其中任意两株混合培养之后，发现F2和F6发酵液的絮凝率较原来的单株菌均有提高，因此这两株菌成为后续发酵的主要菌种。通过摇床试验确定了制取该絮凝剂的发酵条件，并就其对源水的处理效果作了测定。     

复合型生物絮凝剂产生菌的发酵性能研究

对复合型生物絮凝剂产生菌F2和F6的发酵性能进行了研究。经鉴定,F2和F6分别为放射根瘤菌和球形芽孢杆菌,二者均具有良好的高效产絮遗传稳定性。在相同的发酵条件下,砣与F6的混合培养较二者单独发酵更利于生物絮凝剂的生产,发酵24h即进入对数生长的后期,时间缩短为纯培养的1／2,同时最佳絮凝率提高至95．2％。F2与F6混合培养的最佳发酵时间为24h,混培比例为2：1。发酵时间为24、48、72、96、120h时,投加量在5mL／L左右出现一个絮凝高效区。当发酵时间为24h、投加量为5～12mL／L时絮凝率〉91．4％,平均值达到93．0％,复合型生物絮凝剂的这一特性可以有效避免发生返混现象,并提高了抗负荷冲击能力。     

利用固定化XN1菌连续生产微生物絮凝剂的研究

以多孔聚氨酯泡沫为载体,对固定化絮凝剂产生菌进行摇瓶及发酵罐连续培养试验研究,并通过比较不同初糖浓度、菌龄、转速和发酵周期对固定化XN1菌的生长及其产絮凝剂效能的影响,优化了连续生产絮凝剂的条件.结果表明:在摇瓶中,利用糖浓度为2%的初培养基,在150 r/min、28℃下培养60 h即可获得较高活性的固定化细胞;将固定化细胞接种于1%糖浓度的发酵培养基中,振荡速率调至100 r/min,每8 h更换一次培养基,可连续生产12批次高活性絮凝剂,絮凝活性均在78%以上.采用2 L发酵罐优化工艺,连续生产12批次絮凝剂仅需6.5 d,且所得絮凝剂的絮凝活性均在85%以上,与游离菌生产絮凝剂相比,生产效率提高了453.8%.这说明利用多孔聚酯泡沫颗粒作为固定化载体、分段培养、连续发酵生产絮凝剂的方法是可行的、经济的.     

利用淀粉废水培养复合型絮凝剂产生菌研究

利用淀粉废水驯化、培养复合型微生物絮凝剂产生菌,并对其培养条件如废水COD浓度、氮源、营养比以及培养时间等进行了研究。结果表明,由复合型絮凝剂产生菌M17合成的絮凝剂——CMBF-17的絮凝效果最好;M17菌株的最优培养条件是：COD浓度为4 000 mg/L,氮源为尿素,C∶N∶P=100∶5∶2,培养时间为42 h,培养温度为30℃,摇床转速为150 r/min;在该条件下得到的CMBF-17对高岭土悬液的絮凝率达90%,当被用于处理养殖废水、印钞废水、印染废水及府南河水时,对COD、浊度及色度的去除率最高分别可达54%、88%和75%。     

防腐剂对复合型生物絮凝剂防腐保质性能的影响

分别探讨了山梨酸钾、月桂酸单甘油酯两种防腐剂对复合型生物絮凝剂防腐保质方面的影响,同时考察了复合型生物絮凝剂的絮凝率以及细菌总数等指标.试验结果表明:添加两种防腐剂能够有效延长复合型生物絮凝剂絮凝率的高效稳定性,同时有效抑制细菌等微生物的生长繁殖.综合防腐剂价格、絮凝率稳定性以及抑制细菌总数效果等因素,确定单独添加0.50 g/L山梨酸钾或单独添加0.15 g/L月桂酸单甘油酯为最佳处理,保质期从原来的3个月延长到9个月.     

制酒废水培养复合型生物絮凝剂产生菌的研究

为了提高微生物絮凝剂的产量，增强其絮凝效果和稳定性，扩大其应用范围，利用制酒废水培养了4株酵母菌类絮凝剂产生菌，并考察了它们的最佳培养条件。混合培养的结果表明，具有最高絮凝率的混合菌株为HJ4，其最佳培养条件是：相对接种量为15％，培养基初始pH值为4．5，碳氮比为20：1，废水的COD为12000mg／L，在该条件下所产絮凝剂的絮凝率可达94．7％。混合菌株HJ4所产复合型絮凝剂MBF4对实际废水的色度和浊度的去除率均在80％以上，对COD的去除率为20％～90％，说明利用制酒废水培养混合型酵母类絮凝剂产生菌是完全可行的。     

微生物絮凝剂在给水处理中的应用及其动力学研究

从活性污泥中筛选得到一株微生物絮凝剂产生菌,该菌能够利用玉米淀粉废水作为培养基生产微生物絮凝剂M-127.将M-127应用于自来水原水的絮凝试验,结果表明:M-127对原水的絮凝效果优于目前常用的给水絮凝剂,当M-127投加量为6 mg/L,以200 r/min搅拌1min,60 r/min搅拌3 min,静置20 min后,浊度去除率达到93.89%.同时,还研究了M-127在此最佳条件下的浊度去除动力学,并得到了动力学经验方程.     

混合菌利用制酒废水产生微生物絮凝剂的研究

从成都某污水处理厂活性污泥中分离、筛选了2株絮凝剂产生茵,初步鉴定为蜡状芽孢杆菌(Bacillus cereus)和膜璞毕赤酵母(Pichia membranifaciens).利用制酒废水替代成本较高的传统培养基对这两株菌的混合菌(HXJ-1)的最佳产絮条件和絮凝剂的最佳絮凝条件进行了研究,得出了HXJ-1的最佳产絮务件:废水COD为12 000 mg/L,C/N值为20:1,相对接种量为10%(体积分数,菌体浓度为1×108个/L),初始pH值为3.6(制酒废水自然pH),摇床转速为120r/min,培养温度为30℃.在此条件下,发酵24 h所产生的絮凝剂XJBF-1)对高岭土悬浊液的絮凝率平均为89.50%.以浓度为l g/L的高岭土悬浊液(93 mL)为试验对象,得出了XJBF-1的最佳絮凝条件,即:絮凝体系的pH值为7;絮凝剂用量为2 mL;以l%的CaCl2为助凝剂,其投量为5mL.     

A novel bioflocculant produced by Klebsiella sp. and its application to sludge dewatering

A bioflocculant‐producing bacterium, named N‐10, was isolated from activated sludge and was identified as Klebsiella sp. The bioflocculant (named MBF10) produced by Klebsiella sp. had a good flocculating capability and could achieve a flocculating rate of 86.5% to kaolin suspension at the dosage of 0.034 g/L. Compared with chemical flocculants, such as Al₂(SO₄)₃, polyaluminum chloride (PAC) and cationic polyacrylamide (PAM) at their optimal dosages, MBF10 showed a similar performance for sludge dewatering. After preconditioning, dry solids (DS) and specific resistance to filtration (SRF) of the sludge were 17.5% and 3.36 × 10¹² m/kg, respectively. The combined use of MBF10 and Al₂(SO₄)₃ resulted in optimum sludge dewatering properties, SRF reduced from 10.87 × 10¹² m/kg to 1.72 × 10¹² m/kg, and DS increased from 13.1% to 21.3%. Charge neutralisation and interparticle bridging were proposed as the reasons for the enhanced performance based upon the experimental observations.     

Enhanced efficiencies of sludge dewatering and domestic wastewater treatment by using the bioflocculant from rice stover

Potential of a bioflocculant from rice stover was studied in sludge dewatering and domestic wastewater treatment. Production of this bioflocculant showed good correspondence to cell growth, after fermentation for 60 h, the fermentation liquor was obtained, from 1.0 L of which a value of 2.37 g bioflocculant can be extracted, and the main backbone of this bioflocculant was polysaccharides. Without adjusting the sludge's initial pH value of 6.5, when incubated with 18 mg/L of this bioflocculant, dry solids (DS) and specific resistance to filtration (SRF) of the typical wastewater activated sludge reached 18.5% and 4.7 × 10¹² m/kg, respectively, which was better than the ones achieved by Al₂(SO₄)₃ and FeCl₃ flocculants. For domestic wastewater treatment, after treated by 12 mg/L of this bioflocculant at pH value of 7.5, removal efficiencies of chemical oxygen demand (COD) and turbidity can reach 91.8 and 89.7%, respectively, which were better than the ones achieved by the traditional flocculants such as Al₂(SO₄)₃, FeCl₃, and polyaluminum chloride (PAC). This study suggested that the bioflocculant from rice stover has great potentials as an alternative flocculant to conventional flocculants in sludge dewatering and domestic wastewater treatment.     

微生物絮凝剂在给水处理中的应用研究

从土壤中分离筛选得到一株能产高效絮凝剂的硅酸盐芽孢杆菌,该菌产生的絮凝剂MBFA9具有用量少、絮凝效果好等特点。在5000mg／L的高岭土悬浮液中使用该絮凝剂,絮凝率高达99.6%,絮凝剂（培养液）用量仅为0.1mL/L,约为一般生物絮凝剂用量的1／10－1／200,提纯分析发现絮凝剂MBFA9由含有糖醛酸、中性糖和氨基糖的多糖构成。动物急毒性试验表明该始凝剂无急毒反应。     

微生物絮凝剂的研究现状及其发展趋势

微生物絮凝剂因其高效的絮凝效果和安全无毒的特性,已成为近年来国内外研发的热点之一。综述了产絮微生物种类及代谢途径、微生物絮凝剂的絮凝机理研究现状、微生物絮凝剂的发酵生产以及微生物絮凝剂在水污染控制方面的应用,并对复合型微生物絮凝剂的特点、发酵工艺、应用前景及其安全性评价进行了较为详细的介绍。在此基础上,剖析了目前微生物絮凝剂研究工作中存在的问题,提出今后微生物絮凝剂研究的主要发展趋势。     

石墨加工废水工程实例

采用钙盐沉淀 混凝沉淀工艺处理石墨加工废水,废水水量200m3/d,进水水质:[F-]≤500mg/l、SS≤300mg/l、pH=2~4,出水水质满足《污水综合排放标准》(GB8978-96)中的二级标准.采取投加石灰的钙盐沉淀处理法及投加聚和氯化铝的混凝沉淀法的二道工序的处理工艺,处理水的含氟量最低可降到2mg/L左右,一般在5mg/L左右.     

Denitrification potential of industrial wastewaters

Nitrate utilisation batch experiments have been carried out with different agro-food industrial wastewaters. The results obtained were modelled using a modification of the ASM2d to determine the main kinetic and stoichiometric parameters: denitrification rate with fermentation products (q(N-SA)) and with fermentable substrates (q(N-SF)); fermentation products and fermentable substrates consumption rates, (qSA) and (qSF), respectively; yield coefficient with fermentation products (Y(H-SA)) and with fermentable substrates (Y(H-SF)) and saturation coefficient for growth on fermentation products (K(H-SA)). It was found that fermentation products (SA) and fermentable substrates (SF) consumption rates can be assumed to be both constant and independent of the agro-food industrial wastewater used, with values of 14.6 and 5.4 (mg S(COD) g COD-X(-1)OHO h(-1)), respectively. The mean denitrification rates obtained with each agro-food industrial wastewater ranged from 1.5 to 2.5 (mg S(N) g COD-X(-1)OHO h(-1)), values slightly lower to the obtained with domestic wastewater (2.7 mg S(N) g COD-X(-1)OHO h(-1)). Given the substrate consumption rate and the denitrification rate, the yields with fermentation products and fermentable substrates for each wastewater were determined. The values obtained for the yields ranged from 0.50 to 0.69 on using SA and from 0.50 to 0.70 on using SF. Having determined these parameters, the denitrification potential (DNP) was evaluated for each agro-food wastewater. Wastewater from slaughterhouses gave the lowest DNP (22.6 mg S(N) g S(-1)COD), whereas wastewater from potato and tomato processing plants gave the highest values (126.5 and 128.2 mg S(N) g S(-1)COD), respectively), which are very similar to that obtained with domestic wastewater (130.3 and 128.2 mg S(N) g S(-1)COD). Taking into account the low N/COD ratio presented in the agro-food wastewaters, the last wastewaters are the most indicated to enhance the nitrogen removal in the WWTP. Finally, a relationship between the denitrification rates of several agro-food industrial wastewaters and their respective S(A)/(S(A) + S(F)) ratio was obtained. This relationship can be used to estimate the mean denitrification rate of an agro-food industrial wastewater.     

无机絮凝剂添加超细材料用于污水净化处理的研究

把超细材料（二氧化硅、天然沸石）添加到无机絮凝剂当中,进行了城市污水处理的试验研究和猪场粪污水深度处理的初步研究.结果表明,对于城市污水,无机絮凝剂的复合使用效果好于单一絮凝剂;絮凝剂中添加少量的超细SiO2、沸石能提高絮凝效果,对COD的去除率可提高约26%,污泥体积减少32%,增加了污泥密度并降低了后续处理的难度,沉降时间也大为缩短（比未添加超细材料的絮凝剂）.超细复合絮凝材料在对猪场粪污水的深度处理中也有较好的效果：添加超细材料的絮凝剂可提高对污水的脱色率,明显地提高了出水的pH值.     

Fermentation of agro-food wastewaters by activated sludge

This study investigates the potential of agro-food wastewater fermentation by activated sludge. Experimental results shown that all of the agro-food wastewaters studied initially had considerable concentrations of fermentable substrates, ranging from 19% to 68% of the total COD, but not all of the substrates contained in this COD fraction were fermented after an anaerobic stage of 10h. The percentage of fermentable substrates fermented by the activated sludge during the anaerobic stage ranged from 14% to 68%, presenting the potato processing wastewater the highest concentration of fermented substrates. A mathematical model was proposed to describe the fermentation process. By using this model, the maximum fermentation rates were obtained, ranging their values from 0.6 to 3.4 (gCODgCOD(-1)d(-1)). The fermentation potentials of the agro-food wastewaters were also determined, their values ranged from 0.17 to 0.20 (gCODgCOD(-1)) except for the cheese and the winery wastewater which presented fermentation potentials of 0.12 and 0.14 (gCODgCOD(-1)), respectively.     

枯草芽孢杆菌产高效微生物絮凝剂的研究

从污水处理厂的活性污泥中筛选出一株高效絮凝剂产生菌TJHJ1,通过生理生化试验、电镜扫描、16S rDNA相似性分析鉴定其为枯草芽孢杆菌.考察了pH、Ca2+投量和发酵菌液量对该产絮菌絮凝效果的影响,并研究了其生长曲线.结果表明,当pH值为8.5、1%的CaCl2加入量为3.5 mL和菌液加入量为2 mL时,TJHJ1对高岭土悬浊液的絮凝效果最佳,絮凝率达到97%;在培养了36 h后生物量达到最大值,培养54 h后进入内源代谢期.