臭氧化对臭氧耦合ASBR/SBR工艺硝化、反硝化的影响

针对臭氧耦合ASBR/SBR污泥减量化工艺,研究了臭氧氧化对硝化和反硝化能力的影响。结果表明,在臭氧投加量为0.074gO3/gSS左右的条件下,系统进水的COD平均值由氧化前的659mg/L增加到氧化后的713mg/L,碳源量提高了8.2%。进水氨氮由34.3mg/L增加到39.9mg/L,出水氨氮由1.7mg/L升高至1.9mg/L,硝化能力基本未受到影响。SBR段的出水NO3--N平均值由5.85mg/L下降为2.2mg/L,表明系统的反硝化能力增强。投加臭氧前后,系统进水TN平均值分别为49.1mg/L和52.9mg/L,出水TN平均值分别为10.9和13.4mg/L,对TN的平均去除率分别为77.7%和74.6%。可见,臭氧氧化未对SBR段的硝化和反硝化效果产生明显影响。     

臭氧破解活性污泥的试验研究

采用鼓泡型臭氧接触反应柱,探讨了臭氧氧化对活性污泥性状的影响。结果表明,反应初期MLSS降幅不大,在臭氧投量为0.04～0.10 gO3/gMLSS阶段,臭氧直接作用于污泥,MLSS下降明显;MLVSS呈现与MLSS类似的下降趋势;随着臭氧投量的增加,MLVSS/MLSS值从初期的0.75降至试验末期的0.60。臭氧溶胞引起上清液中SCOD浓度的上升,但同时由于臭氧的矿化作用导致其增加量低于经验值,为0.628 4 gSCOD/gMLVSS。另外,上清液中硝态氮和总氮浓度呈上升趋势,氨氮浓度先上升后下降,在臭氧投量为0.08 gO3/gMLSS时达到最大。     

臭氧投量对活性污泥特性参数的影响

通过试验分析和探讨了臭氧投量对活性污泥特性参数的影响.结果表明,随着臭氧投量的增加,SS和VSS呈明显降低的趋势,而活性污泥上清液中的SCOD、蛋白质、总氮及硝酸盐氮则增加;氨氮浓度总体上随臭氧投量的增加而增加,但在投量为95～137 h mgO3/gSS时有所下降,随后又明显增加;当臭氧投量<137 mgO3/gSS时,亚硝酸盐氮呈增加趋势,随后开始明显降低;当臭氧投量<211 mgO3/SSS时,TOC和多糖随臭氧投量的增加而增加,随后开始下降.     

纳米絮凝剂在SBR系统中的应用

借助高效絮凝剂强化传统SBR工艺,从而使其具有类似好氧颗粒污泥工艺的优势,旨在为解决现有污水厂的提标改造、提升处理负荷和实现高品质出水的难题提供新思路。通过对出水水质和活性污泥性能的分析发现,向SBR系统中长期投加纳米絮凝剂能够改善出水水质,并可维持反应器的高效稳定运行。当纳米絮凝剂的投加量为50μL/L时,对COD、TP、氨氮和TN的平均去除率较高,分别可达92. 3%、91%、97. 3%、40. 7%。投加纳米絮凝剂对MLSS和SVI的影响显著,MLSS在纳米絮凝剂投加量为50μL/L时达到最大,为6. 5 g/L,SVI值在纳米絮凝剂投加量为100μL/L时达到最低,为25 m L/g。纳米絮凝剂的加入对MLVSS/MLSS的影响不明显。     

固定化生物催化剂用于污水厂污泥减量的研究

目前,剩余污泥的处理与处置已成为困扰污水厂的难题之一.采用固定化生物催化剂(IBC)在某城市污水处理厂进行污泥减量试验,结果表明:投加IBC的CASS池污泥减量效果明显,投药1个月后,外排剩余污泥量及产泥量均大幅减少,第3,4个月没有外排剩余污泥,且MLSS维持在1500 mg/L左右,有效地从源头实现了污泥减量.同时,投加IBC对出水水质无负面影响,且能够提高水质净化效果,投药池对COD、NH3-N、TP的平均去除率分别为84.18%、94.39%、63.17%,较对照池的79.88%、92.80%、49.61%均有所提高,出水水质优于对照池.     

臭氧+Flopac~(TM)工艺去除化工废水中难降解有机物

如何经济、有效地去除难降解有机物是当前水处理领域的难题之一。针对臭氧+FlopacTM工艺对化工废水难降解有机物的去除效果开展中试研究,并应用于具体工程实例。中试结果表明,增加臭氧投加量可有效提高化工废水的可生化性,当臭氧投加量由35 mg/L增加到75mg/L时,出水B/C值由0. 13提高到0. 17,对COD的去除率由27%提高到38%,出水COD浓度稳定在60 mg/L以下。实际工程运行数据表明,臭氧+Flopac~(TM)工艺可有效去除化工废水中的难降解有机物,出水水质稳定,臭氧投加量为65 mg/L、Flopac~(TM)平均滤速为6. 7 m/h时,COD去除率达到44%。     

臭氧对陶瓷膜去除地表水中有机物的影响研究

采用臭氧氧化技术改善陶瓷膜对钱塘江原水的处理效果,基于臭氧对膜出水中有机物的氧化作用,探讨不同的臭氧投加方式对陶瓷膜过滤特性的影响。结果表明,臭氧可较好地去除有机物,提高膜过滤通量。当臭氧投加量为5 mg/L时,对DOC和UV254的去除率可由未投加臭氧时的34%和22. 5%提高到44. 6%和40%;臭氧可有效提高陶瓷膜的膜通量,且随臭氧投加量的增加而逐步提高,臭氧投加量为5 mg/L时,膜比通量较未投加臭氧时提高了18. 3%;膜的化学清洗液的分析结果表明,臭氧氧化了污染陶瓷膜的一些有机物质,从而减少了膜污染,提高了膜通量。     

水厂药剂投加优化与应用

通过分析各净水药剂间关联性,确定了聚合氯化铝(PAC液体)、臭氧、聚丙烯酰胺(PAM)的最佳投加量,在保证出水水质的前提下,有效控制了药剂成本。生产运行表明,预臭氧最佳投加量为0. 5～0. 7 mg/L,可显著提高絮凝效果,使PAC投加量降低20. 7%;在控制PAC用量的基础上,合理控制平衡池污泥浓度(最佳3%),可减少58. 9%的PAM投加量。降低2种药剂的使用量并控制泥饼含水率后,污泥运输量减少了54%,大大降低水厂的运行成本。     

臭氧临界氧化进行活性污泥碳源转化研究

我国污水处理厂规模和数量迅速增加,污水处理过程排放的污泥处理和处置问题日益突出。污泥减量化和资源化是解决污泥问题的一条可持续途径。本文采用臭氧临界氧化工艺进行污泥减量化,将其转化成为碳源,效率高,能耗低。本文试验了臭氧投加量和臭氧投加方式对污泥消解效果,碳源转化效果,评价了臭氧临界氧化对污泥和混合液特性的影响,臭氧临界投加量为80g-O_3/kg污泥。臭氧投加初始浓度越大,臭氧流量越大,污泥细胞物质包括多糖和蛋白质等溶出速率越快,碳源转化效果越好,污泥减量化效果越好,平均减量化效率达到64%左右。本项研究对于指导污水厂剩余污泥的减量化和碳源转化利用具有重要的意义。     

利用微生物制剂进行污泥减量的生产性试验研究

在重庆市江津区的德感污水处理厂开展了利用多功能复合微生物制剂（MCMP）进行污泥减量的生产性试验研究,结果表明：在氧化沟的好氧段投加MCMP,当投加频率为1次／月、每次的投加量为日处理水量的0.005％时,污泥减量效果明显,系统运行了6个月而没有外排剩余污泥。投加MCMP后不仅能保证污水处理厂的出水水质达到《城镇污水处理厂污染物排放标准》（GB18918-2002）的一级B标准,而且还强化了对氮、磷的去除。该技术不用增加或改变原有污水处理设施,也无需改变原有工艺的运行方式,具有显著的经济、环境和社会效益。     

Advanced sewage treatment process with excess sludge reduction and phosphorus recovery

An advanced sewage treatment process has been developed, in which excess sludge reduction by ozonation and phosphorus recovery by crystallization process are incorporated to a conventional anaerobic/oxic (A/O) phosphorus removal process. The mathematical model was developed to describe the mass balance principal at a steady state of this process. Sludge ozonation experiments were carried out to investigate solubilization characteristics of sludge and change in microbial activity by using sludge cultured with feed of synthetic sewage under A/O process. Phosphorus was solubilized by ozonation as well as organics, and acid-hydrolyzable phosphorus (AHP) was the most part of solubilized phosphorus for phosphorus accumulating organisms (PAOs) containing sludge. At solubilization of 30%, around 70% of sludge was inactivated by ozonation. The results based on these studies indicated that the proposed process configuration has potential to reduce the excess sludge production as well as to recover phosphorus in usable forms. The system performance results show that this system is practical, in which 30% of solubilization degree was achieved by ozonation. In this study, 30% of solubilization was achieved at 30 mgO(3)/gSS of ozone consumption.     

The effect of operational parameters of the process of sludge ozonation on the solubilisation of organic and nitrogenous compounds

An evaluation of various operational parameters on the process of sludge ozonation was carried out based on semi-batch experiments. Particular reference has been given to examine the main parameters affecting the solubilisation of organic matter and nitrogenous compounds. Various sets of experiments were undertaken using real sewage sludge to feed a semi-industrial ozonation plant. Applying ozone dosages between 25 and 35 mg O(3)/gTSS, the organic matter solubilisation obtained through ozonation increases proportionally to ozone dosage until a maximum value of 430 mg COD/L. Concerning the nitrogenous compounds, no variation in nitrite concentration and a low increase in nitrate concentration were attained, regardless of the applied ozone dosage. Little increase in ammonia concentration was achieved for low ozone dosages, whilst applying dosages higher than 20 mg O(3)/gTSS, the variation of ammonia increased proportionally with ozone dosage. Experiments using hydraulic retention time (HRT) between 10 and 60 min resulted in a similar COD solubilisation, confirming a rapid rate of cell lysis during ozonation of sludge.     

Behavior of inorganic elements during sludge ozonation and their effects on sludge solubilization

The behavior of inorganic elements (including phosphorus, nitrogen, and metals) during sludge ozonation was investigated using batch tests and the effects of metals on sludge solubilization were elucidated. A decrease of ∼50% in the ratio of sludge solubilization was found to relate to a high iron content 80-120 mgFe/gSS than that of 4.7-7.4 mgFe/gSS. During sludge ozonation, the pH decreased from 7 to 5, which resulted in the dissolution of chemically precipitated metals and phosphorus. Based on experimental results and thermodynamic calculation, phosphate precipitated by iron and aluminum was more difficult to release while that by calcium released with decrease in pH. The release of barium, manganese, and chrome did not exceed 10% and was much lower than COD solubilization; however, that of nickel, copper, and zinc was similar to COD solubilization. The ratio of nitrogen solubilization was 1.2 times higher than that of COD solubilization (R² = 0.85). Of the total nitrogen solubilized, 80% was organic nitrogen. Because of their high accumulation potential and negative effect on sludge solubilization, high levels of iron and aluminum in both sewage and sludge should be considered carefully for the application of the advanced sewage treatment process with sludge ozonation and phosphorus crystallization.     

Progress and perspectives of sludge ozonation as a powerful pretreatment method for minimization of excess sludge production

The treatment and disposal of excess sludge represents a bottleneck in wastewater treatment plants (WWTP) worldwide, due to environmental, economic, social and legal factors. The ideal solution to the problem of sludge disposal is to combine sludge reduction with the removal of pollution at the source. This paper presents an overview of the potential of ozonation in sludge reduction. The full-scale application of ozonation in excess sludge reduction is presented. Improvements in the biodegradability of the ozonated sludge were confirmed. The introduction of ozonation into activated sludge did not significantly influence effluent quality but improved the settling properties of the sludge. An operation with a suitable sludge wasting ratio seems to be necessary to prevent accumulation of inorganic and inert particles for long-term operation. Sludge ozonation to reduce excess sludge production may be economical in WWTP which have high sludge disposal costs and operational problems such as sludge foaming and bulking. The recommended ozone dose ranges from 0.03 to 0.05 g O₃/g TSS, which is appropriate to achieve a balance between sludge reduction efficiency and cost. An effort to design and optimize an economic sludge reduction process is necessary.     

Ozone Treatment of Sewage Works' Final Effluent

This paper describes a laboratory-based study which was designed to investigate (a) the changes in selected physico-chemical properties of a sewage-works' final effluent after ozonation, and (b) the effect of ozone on the concentration of organic halides and effluent toxicity and mutagenicity. Different conditions were studied involving the application of ozone concentrations up to 13.5% w/w and the ozonation of the effluent under both constant and variable ozonation rates.     

Conventional and (eco) toxicological assessment of batch partial ozone oxidation and subsequent biological treatment of a tank truck cleaning generated concentrate

This paper compares the treatment efficiencies of direct (pH 7.5) and advanced (pH 11.5) partial ozonation followed by biodegradation for the treatment of tank cleaning wastewater concentrate. Both S_COD and toxicity removal efficiencies are examined and direct ozonation is found to perform better in combined toxicity and S_COD removal. Optimal process performance, i.e. the minimal ozone dosage resulting in a maximal removal of S_COD and toxicity in the final effluent, is reached upon reaction of 500 mg O₃/l for both ozonation processes. This ozone dosage results in 60% S_COD reduction for direct ozonation and 64% S_COD reduction for advanced ozonation. A 79% toxicity reduction was achieved using direct ozonation compared to 53% toxicity reduction for advanced ozonation as measured with the standard Pseudokirchneriella subcapitata algal 72 h growth inhibition test. Short-term methods for biodegradability (respirometry) and toxicity (30 min Vibrio fisheri luminescence inhibition) estimation are evaluated in view of process control. The maximal specific oxygen uptake rate of an activated sludge culture (respirometry) is found to relate to the 5-day biochemical oxygen demand (S_BOD,5) but less to the actual S_COD removal during biodegradation. The 30 min Vibrio fisheri luminescence inhibition test is found to be a good short-term estimator for relative changes in toxicity when compared to the standard P. subcapitata algal 72 h growth inhibition test. The 500 mg O₃/l optimal ozone dosage, as determined from P. subcapitata algal 72 h growth inhibition and S_COD removal, could be retrieved using short-term methods.     

Effects of ozone pre-treatment on diclofenac: Intermediates, biodegradability and toxicity assessment

Diclofenac (DCF), a common analgesic, anti-arthritic and anti-rheumatic drug, is one of the most frequently detected compounds in water. This study deals with the degradation of diclofenac in aqueous solution by ozonation. Biodegradability (BOD₅/COD ratio and Zahn-Wellens test), acute ecotoxicity and inhibition of activated sludge activity were determined in ozonated and non-ozonated samples. Liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOF-MS) was used to identify the intermediates formed in 1 h of ozonation. Eighteen intermediates were identified by these techniques and a tentative degradation pathway for DCF ozonation is proposed.Experimental results show that ozone is efficient at removing DCF: > 99% removal (starting from an initial concentration of 0.68 mmol L^− 1) was achieved after 30 min of ozonation (corresponding to an absorbed ozone dose of 0.22 g L^− 1, which is 4.58 mmol L^− 1). However, only 24% of the substrate was mineralized after 1 h of ozonation. The biodegradability, respiration inhibition in activated sludge and acute toxicity tests demonstrate that ozonation promotes a more biocompatible effluent of waters containing DCF.     

Elimination of resin acids by advanced oxidation processes and their impact on subsequent biodegradation

Wood pulping and paper production generate a considerable amount of wastewater, containing many pollutants among them resin and fatty acids. Resin acids contribute substantially to effluent toxicity and were identified to be detrimental to microorganisms of activated sludge and in particular to bacteria in anaerobic wastewater treatment system and other forms of aquatic life. The objective of the present study was to check the applicability of the ozone and advanced oxidation processes (AOPs) to eliminate resin acids from aqueous solutions and to determine the ozone dose required. Furthermore, an investigation of the influence of the oxidation methods on subsequent biological destruction of the byproducts was performed. Aqueous solution of the resin acids: abietic, dehydroabietic and isopimaric acids with different initial composition were subjected to ozonation or AOP processes at different ozone doses. After ozonation or advanced oxidation pretreatment the model solutions were biodegraded in aerated vessels containing activated sludge. During ozonation of the resin acids aqueous solutions the resin acids were almost eliminated, however the reduction of chemical oxygen demand (COD) was rather low. The ozone dose required to obtain reduction of resin acids >90% was in the range of 0.1-0.7mgO(3)/mgCOD, depending on the composition and concentration of model solutions. The toxicity of ozonated resin acids solutions decreased with increasing applied ozone dose up to about 0.3-0.5mgO(3)/mgCOD, thereafter increased. Ozonation and other AOP processes did not increase the rate of biodegradation of resin acids model solutions in aerated activated sludge systems compared to not pretreated solutions.