Preliminary Study on the Treatment Efficiency of Pasteurized Lime Thermal Alkaline Hydrolysis for Excess Activated Sludge and Reduction of Tetracycline Resistance Genes

Thermal alkaline hydrolysis is a common pretreatment method for the utilization of excess activated sludge(EAS).Owing to strict environment laws and need for better energy utilization,new methods were developed in this study to improve the efficiency of pretreatment method.Direct thermal hydrolysis(TH),pasteurized thermal hydrolysis(PTH),and alkaline pasteurized thermal hydrolysis(PTH+CaO and PTH+NaOH)methods were used to treat EAS.Each method was compared and analyzed in terms of dissolution in ammonium nitrogen(NH_(4)^(+)-N)and soluble COD(SCOD)in EAS.Furthermore,the removal of tetracycline resistance genes(TRGs)and class 1 transposon gene intI1 from EAS was investigated.The NH_(4)^(+)-N and SCOD concentrations in EAS treated by PTH were 1.24 and 2.58 times higher than those of TH.However,the removal efficiency of total TRGs and intI1 between the groups was comparable.The SCOD concentration of the PTH+NaOH group was 4.37 times higher than that of the PTH group,and the removal efficiency of total TRGs was increased by 9.52%compared with that by PTH.The NH_(4)^(+)-N and SCOD concentrations of the PTH+CaO group could reach 85.04%and 92.14%of the PTH+NaOH group,but the removal efficiency of total TRGs by PTH+CaO was 19.78%lower than that by PTH+NaOH.Thus,to reduce the financial cost in actual operation,lime(CaO)can be used instead of a strong alkali(NaOH),and pasteurized steam at 70℃ instead of conventional high-temperature heating to treat EAS.This study provides a reference for the development of alkaline hydrolysis under moderate temperatures along with the removal of TRGs in EAS.

Extraction of Amino Acids from Excess Activated Sludge by Enzymatic Hydrolysis

A study was undertaken to investigate the production of amino acids from excess activated sludge (EAS) by enzymatic hydrolysis. Firstly, the protein was extracted from EAS. Secondly, the protein solution was further hydrolyzed under free enzyme or immobilized enzyme. The reversed phase high performance liquid chromatography (RP-HPLC) and inductively coupled plasma emission spectrometer (ICP) were applied to determine the contents of amino acids and heavy metals, respectively. The effects of enzyme/substrate(E/S), pH, temperature, and reaction time were investigated in detail. The results indicated that, the optimum conditions for protein hydrolysis were temperature 55℃, pH 10, E/S 9 g/L, and reaction time 8 h, and the highest yield of amino acids was more than 10 g/100 g dry sludge (DS) under free enzyme. Moreover, the security and nutrition were taken into consideration. There were seven kinds of essential amino acids and ten non-essential amino acids in the raw amino acid (RAA) solution, and the contents of heavy metals were lower, living up to Hygienical standard for feeds (China). This technology widens the source of amino acids and makes the extraction of amino acids from EAS more economic and effective.

Effect of Combined Microwave-Ultrasonic Pretreatment on Anaerobic Biodegradability of Primary, Excess Activated and Mixed Sludge

This work deals with the effect of combined microwave-ultrasonic pretreatment on the anaerobic biodegradability of primary, excess activated and mixed sludge. The characteristics, biodegradability and anaerobic digester performance for untreated primary, excess activated and mixed sludge were compared to combined microwave-ultrasonic pretreated primary, excess activated and mixed sludge. All sludge samples were subjected to Microwave treatment at 2450 MHz, 800 W and 3 min followed by ultrasonic treatment at a density of 0.4 W/mL, amplitude of 90%, Intensity of 150 W, pulse of 55/5 for 6min. Methane production in pretreated primary sludge was significantly greater (11.9 ml/g TCOD) than the methane yield of the untreated primary sludge (7.9 ml/g TCOD). Cumulative methane production of pretreated Excess Activated Sludge (EAS) was higher (66.5 ml/g TCOD) than the methane yield from pretreated mixed sludge (44.1 ml/g TCOD). Furthermore, digested EAS showed significantly higher dewaterability (201 s) than digested primary sludge (305 s) or mixed sludge (522 s). The average Methane: Carbondioxide ratio from EAS (1.85) was higher than that for mixed untreated sludge (1.24). VS reduction was also higher for EAS than the other two sludge types. However, pretreatment of EAS resulted in significant reduction in dewaterability due to higher percentage of fine floc particles in the pretreated EAS.

Hydrolysis and acidification of activated sludge from a petroleum refinery

The cost-effective treatment of activated sludge that is generated by refining petroleum is a challenging industrial problem.In this study, semi-continuous stirred tank reactors(CSTRs) containing petroleum refinery excess activated sludge(PREAS)were used to comparatively investigate hydrolysis and acidification rates, after the addition of heneicosane(C_(21)H_(44))(R1)and 1-phenylnaphthalene(C16 H12)(R2) to different and individual reactors. Operation of the reactors using a sludge retention time(SRT) of 6 days and a pH of 5.0, resulted in the maintenance of stable biological activity as determined by soluble chemical oxygen demand(SCOD), volatile fatty acids(VFAs) production and oil removal efficiency. The optimum conditions for hydrogen production include a SRT of 8 days, at pH 6.5. Under these conditions, hydrogen production rates in the control containing only PREAS were 1567 mL/L(R0), compared with 1365 mL/L in Rl and 1454 mL/L-PREAS in R2.Coprothermobacter, Fervidobacterium, Caldisericum and Tepidiphilus were the dominant bacterial genera that have the potential to degrade petroleum compounds and generate VFAs. This study has shown that high concentrations of heneicosane and 1-phenylnaphthalene did not inhibit the hydrolytic acidification of PREAS.

Experimental study on zero excess sludge production process with ozonation unit in MBR process

In order to investigate the influence factors of zero excess activated sludge (EAS) process by ozonation, a 100 L membrane bioreactor coupled with a sludge ozonation unit (MBR-SO) was performed for 80 d without EAS wasting. Some mathematical models were developed to elucidate the relationship between process parameters and the operating effects. It is considered that the sludge lysing ratio (ξ), produced COD per unit mass lysed MLSS (η), observed sludge yield coefficient (Yobs) and intrinsic yield coefficient for COD produced by lysed sludge (Y2) significantly affect the flowrate to ozonation unit (q). When q is 0.0067 times of influent flowrate (Q) and ξ is about 0.72 for each batch ozonation, a relatively stable MLSS concentration of 8168 mg/L and zero Yobs are achieved in the MBR-SO system. The calculation of sludge disintegration number indicates that the high ξ can apparently decrease the sludge amount needed for ozonation. At the same ozone dose, the low input ozone concentration and high flowrate can enhance the sludge lysing effects and a low energy consumption of 0.041 Yuan/m3 wastewater is obtained.

基于文献计量学分析的剩余污泥厌氧消化预处理研究进展

污水处理过程中会产生大量剩余污泥,对剩余污泥进行厌氧消化处理既能减少环境污染,又能回收能源。本文基于文献计量学方法和可视化工具,对中国知网(CNKI)数据库和Web of Science核心数据库2003—2023年间收录的相关文章进行梳理,对当前剩余污泥厌氧消化处理的研究热点领域进行比较分析,并对剩余污泥成分、理化特性和厌氧消化预处理方法进行文献综述。研究表明,剩余污泥厌氧消化产生甲烷是该处理技术的重要目的,预处理技术与剩余污泥处理存在重要关联性;物理、化学和生物酶等不同预处理技术对产沼气量有较大影响,针对污泥本身的理化性质而采用更加合适的预处理技术,能够在节约成本的同时进一步提高剩余污泥资源化利用程度。

超声波-游离亚硝酸联合预处理污泥强化厌氧消化的机制解析

本研究对超声波(US)预处理、游离亚硝酸(FNA)预处理及超声波-游离亚硝酸(USFNA)联合预处理对于污泥有机质溶出、絮体分散、细胞内容物释放及产甲烷性能的作用进行评估。结果表明,US预处理的主要作用是使絮体分散与胞外聚合物溶出,FNA预处理则是使细胞内容物释放。US-FNA联合预处理后,污泥甲烷产率较未预处理增加了37.1%,分别达到US预处理的1.07倍和FNA预处理的1.08倍,但US与FNA在联合预处理中所发挥作用各自独立,并未发现明显的协同增效作用。引入FNA会降低污泥厌氧消化初期产气速率,未对累积产气量造成显著影响。根据发酵后污泥微生物菌群的解析,发现FNA是影响污泥微生物多样性的主导因素。

餐厨垃圾和剩余污泥协同处理研究进展

餐厨垃圾和剩余污泥单独处理效率较低,协同处理可以更加高效地资源化利用。本文通过对好氧堆肥、厌氧消化、焚烧/热解等技术协同处理餐厨垃圾和剩余污泥的进展进行分析,探讨了物料比、抑制物质如脂质、盐分、重金属,添加物质如有益菌、生物炭、微量元素对餐厨垃圾和剩余污泥协同处理的效果,旨在为餐厨垃圾和剩余污泥资源化利用提供参考。

黑水虻生物处理餐厨垃圾与剩余污泥的效果

黑水虻生物转化技术可用于餐厨垃圾或剩余污泥的处理,解决其处置和资源化难题。分别考察了餐厨垃圾与剩余污泥在不同混合比例(污泥比例分别为0%、25%、50%、75%、100%)下作为培养底物时的处置转化情况以及黑水虻的生长和重金属富集情况。结果显示:经15 d处理后,不同组别餐厨垃圾和剩余污泥混合物的平均减量率为22.66%~56.16%,平均生物转化率为15.18%~27.84%,且处理后有机废物的恶臭气味消失,处置效果良好。此外,剩余污泥比例低于75%的组别都能保证黑水虻的正常生长,剩余污泥比例为25%和50%组别中,黑水虻的粗蛋白(21.22%、20.50%)和粗脂肪(18.91%、18.50%)含量相较于未添加剩余污泥组(40.75%、37.56%)略低,但其微量元素含量(14.24%、14.59%)相较于未添加剩余污泥组(10.02%)略高,剩余污泥比例为0%和25%的组别中,黑水虻的重金属生物富集系数均在阈值范围内(<1)。未添加剩余污泥培养的黑水虻可用作水生生物饲料,添加剩余污泥培养的黑水虻可作为禽畜饲料添加剂使用,实现固废养殖的黑水虻的资源化利用。

老化轮胎微塑料对剩余污泥厌氧发酵产酸的影响

轮胎微塑料(TMPs)是污水中微塑料的主要来源之一,经污水处理流程后富集于剩余污泥内部,其理化性质及迁移转化影响污泥处理处置。文中采用强酸模拟环境老化的方法,探究老化TMPs对污泥厌氧发酵产酸的影响。结果表明,老化TMPs对污泥厌氧发酵产酸和水解过程都存在明显抑制,TMPs浓度越高,抑制程度越强,高浓度[0.2 g/(g VSS)]老化组挥发酸产量、SCOD_(Cr)、蛋白质和多糖较对照组分别减少了21.5%、40.0%、21.5%和18.6%。老化TMPs能抑制蛋白酶、α-葡萄糖苷酶和乙酸激酶等酶活性,导致功能微生物产生氧化应激反应或死亡。老化后TMPs颗粒粒径减小以及其浸出的有机物是发酵微生物产生氧化应激反应和污泥发酵系统效率降低的主要原因。上述研究结果对污泥厌氧发酵系统运行具有指导意义。

三氯生对剩余污泥碱性发酵及微生物群落结构的影响

考察了三氯生(TCS)对剩余污泥碱性发酵(pH 10)产酸效果的影响。当TCS投加量为400 mg/kg(以TSS计)且发酵5 d时,短链脂肪酸(SCFA)的产量最高,为2740.96 mg/L(以COD计),相比未投加TCS时提高了352.54 mg/L;该体系中,乙酸在SCFA中的占比最高(质量分数达36.73%),以VSS减少率表征的有机质减少率最大(达40.50%),有助于污泥资源化利用。TCS促进了污泥碱性发酵的溶解、水解和酸化过程,同时增强了水解酶的活力,为产酸微生物提供更多底物。TCS显著强化了厚壁菌门和放线菌门微生物在污泥碱性发酵过程中的富集,尤其是厚壁菌门的厌氧醋酸菌属和泰氏菌属微生物(相对丰度分别达15.88%和6.12%),有利于SCFA的积累。

古龙酸母液、木霉菌与活性污泥配施对矸石山黑麦草生理特性及土壤微生物性质的影响

煤矿开采区矸石山由于其有机质含量低、土壤物理结构不良,致使植物生长困难,复垦难度大。针对上述问题,将微生物菌剂与废弃资源配施,以期在矸石山建立适宜先锋植物定植的复垦环境并筛选最优施用方案。以黑麦草(Lolium perenne)为供试植物,选取废弃资源古龙酸母液(RAE)、长枝木霉菌(TL)与剩余活性污泥(AS)为改良剂在矸石山基质生境条件下进行盆栽试验,设置8种不同处理,分别为RAE、TL、AS、RAE+TL、RAE+AS、TL+AS、RAE+TL+AS及CK,评估不同处理对黑麦草生长生理、土壤酶活性及微生物量的影响。结果表明,(1)各处理均能够提高黑麦草的生长指标,其中RAE+TL+AS三施对黑麦草总生物量的提高效果最好,比CK提高了2.52倍;同时各处理总体上能够降低叶片丙二醛含量,提高叶片过氧化氢酶活性、脯氨酸和可溶性糖含量,表明TL、RAE、AS是通过提高植物抗氧化功能而不是通过提高渗透压的方式来提高抗逆性。其中AS单施对提高黑麦草生长、生理性质的效果最好,其生长生理综合指数(PGPI)比CK提高了3.88倍。(2)在土壤酶活性方面,单施处理中AS,配施处理中TL+AS,对蔗糖酶、脲酶、磷酸酶和过氧化氢酶活性提升效果最好。(3)在土壤微生物量方面,RAE+TL+AS三施对微生物量碳的提高幅度最大,比CK提高了1.64倍。各处理中,AS单施处理的土壤微生物质量综合指数(SMQI)最高,但考虑到总生物量(复垦效果),建议矸石山复垦采用三施处理;从成本角度考虑,建议采用AS单施处理。该研究为矿区矸石山复垦提供有益的技术探索,也为古龙酸母液和剩余活性污泥的资源化利用提供了全新的见解和技术支持。

石化剩余活性污泥源头减量化研究进展

活性污泥法具有污染物去除率高、成本低的特点,已成为目前石化企业污水处理场的典型工艺。然而,其广泛的应用产生了大量剩余活性污泥因而造成了废水处理过程中二次污染的排放及高处理成本。因此,有关实现剩余活性污泥源头减量化的理论与工艺亟待研究。目前相关理论包括维持代谢和内源呼吸、解偶联代谢、隐形生长及生物捕食理论,均是通过改变原有微生物的新陈代谢过程(强化或者抑制某个特定过程)实现污泥减量化的目的。已研究的相关工艺包括延长污泥停留时间的膜生物反应器、改变微生物生存环境的好氧-沉淀-厌氧工艺以及投加填料达到延长微生物食物链的生物膜法等工艺。然而,由于石化企业来水水质波动大以及现有污水处理工艺的复杂性,并且各个工艺的局限性包括膜生物反应器的膜污染、好氧-沉淀-厌氧工艺的水质波动及生物膜法的反应器设计等问题,相关工艺的研究及应用受限。通过对已有工艺进行理论分析研究以及简化模拟,可以寻找出实现污泥源头减量化工艺与现有工艺的契合点,最终推动石化企业剩余活性污泥源头减量化的发展。

利用微型动物削减剩余污泥量的研究

在污水的好氧生物处理过程中会产生大量的剩余污泥。污泥的浓缩、脱水、处理和处置需要花费大量的人力和物力 ,而且如果处置不当 ,很容易对环境造成二次污染。因此 ,最大限度减少剩余污泥的排放成为人们关注的问题。根据生态学的理论 ,加强微型动物对细菌的捕食作用 ,可使能量在从低营养级向高营养级传递过程中有一定的损失 ,同时污泥量得以减少。应用两段式生物反应器或者直接向曝气池中投加微型动物均可达到此目的。本文详细地介绍了这两种方法 ,讨论了各自的优点和不足 。

超声波处理剩余污泥有机物、氮和磷的释放特性研究

以生活污水处理厂污泥为研究对象,采用超声波技术研究了污泥破解过程中有机物、氮和磷的释放规律。结果表明,在声能密度为0.167、0.330、0.500W/mL的条件下,污泥中的有机物、氮和磷的释放均随超声时间而增加;破解后污泥释放出的有机物以分子量(MW)≤2000的物质为主,且上清液BOD5/COD>0.33;所释放的氮以有机氮为主,其次是氨氮,污泥破解液COD/凯氏氮平均值为11,适合于生物法脱氮;污泥破解所释放的正磷酸盐约占污泥总磷质量的6.0%～18.2%。利用沉淀结晶法将其回收,可减轻原污水处理工艺的磷负荷。

以剩余污泥减量化为目标的废水生物处理技术研究进展

以剩余污泥减量化为目标 ,针对活性污泥法处理污水而产生大量污泥的现象综述了污水生物处理技术研究的三个主要方面 ,即对剩余污泥的后处理 (污泥产生后再处理 )、减少污水处理过程中污泥的产量和污泥原位降解。

pH值对剩余污泥水解酸化溶出物的影响

在室温条件下(25℃),采用批量实验,研究了pH值在4.0～12.0变化时污泥水解酸化效率情况以及水解过程中溶出的可溶性有机物(SCOD)、挥发性有机酸(VFAs)和氮、磷的质量浓度变化.实验结果表明,污泥水解酸化效率递减顺序为碱性>酸性>中性.ρSCOD、ρVFAs、ρ(NH4+-N)和ρ(PO34--P)随时间延续而增大,并且都随pH值升高(4.0～11.0)而呈现出先减小后增大的趋势.在pH=11.0时,ρSCOD和ρVFAs值最大,分别为2 599 mg/L和749 mg/L;pH=4.0时,ρ(NH4+-N)和ρ(PO43--P)值最大,分别为208.1 mg/L和193.4 mg/L.通过调整pH值能改变污泥水解酸化效率,并且选择pH值在10.0～11.0时,可以协调水解酸化效率与后续脱氮除磷系统N、P负荷之间的关系,既为脱氮除磷系统提供SCOD和VFAs,又可以实现剩余污泥减量.

超声、臭氧处理石化污水厂剩余活性污泥研究

采用超声波和臭氧处理石化污水处理厂的剩余活性污泥,促进其脱水和破解。实验结果表明,小功率超声对污泥脱水效果较好,最佳超声条件为:输出电压70 V,超声时间2 min;污泥抽滤后的含水率在试验范围内随臭氧量的增加而降低,最佳臭氧剂量为0.05 g O3/g SS。经超声处理过的臭氧化污泥要比没经超声处理过的含水率低约1%。在传统的絮凝方法下,加上超声和臭氧可以使污泥含水率再降低2%以上,减少絮凝剂用量近40%;臭氧和超声联合比单独臭氧对污泥破解效果更显著,污泥可减量约25%。臭氧投量较少时,超声破解效果更明显。

污水厂污泥作吸附剂的试验研究

将太原市杨家堡污水厂初沉污泥（编为１＃）、剩余污泥（２＃）及分别加工（炭化——活化）后所得产物（Ａ＃和Ｂ＃）用作吸附剂（“炭”）对污水进行处理，发现这四种“炭”除了对ＮＨ３－Ｎ几乎都无作用外，对ＣＯＤ、Ｆ－及Ｃｄ２＋都有不同程度的去除能力。当投“炭”量为１～６ｇ／Ｌ时，Ａ＃对ＣＯＤＣｒ的去除率相应达３８～７０％。

蚯蚓对剩余污泥中重金属Cu、Zn的活化实验研究

以中国矿业大学南湖校区污水处理站的剩余污泥(简称污泥)为研究对象,通过培养实验,研究污泥中蚯蚓的生长情况和蚯蚓活动对污泥中重金属生物有效性的影响。实验结果表明,蚯蚓能够在一定浓度Cu、Zn的污泥中正常生长,表现出一定的重金属耐性,其耐受能力与重金属的种类、浓度、污泥的理化性质有关。蚯蚓活动能够降低污泥的pH,使之趋于中性。对不同浓度Cu处理污泥,蚯蚓活动使污泥有机质含量均有不同程度下降,其中对Cu为100 mg/kg的污泥中有机质含量影响最大;对不同浓度Zn处理污泥,蚯蚓活动使污泥有机质含量降低的幅度不大。蚯蚓活动可在一定程度上活化污泥中的重金属Cu和Zn,蚯蚓对Cu的活化效果较为明显,在污泥中添加Cu为50 mg/kg时,Cu活化率增加值最大,达到了11.14%;蚯蚓活动对Zn的活化效果不明显,Zn活化率增加值均低于1%。