PPC与粉末活性炭联用处理高藻黄河水的研究

针对民丰水厂常规水处理工艺处理高藻、高有机物含量原水难度大的问题,采用预氯化、高锰酸钾复合药剂（PPC）预氧化、高锰酸钾复合药剂与粉末活性炭联用技术,强化常规水处理工艺进行了小试研究,并在试验结果基础上进行了实际生产性试验。结果表明,采用高锰酸钾复合药剂与粉末活性炭联用具有良好的净水效果,与预氯化相比,澄清池出水中浊度的去除率从34．7％提高到57．0％,CODMn的去除率从23％提高到43．3％,出水UV254〈0．025mg／L。     

高锰酸钾与粉末活性炭联用去除水源水中臭味的研究

在静态试验和中试试验条件下,研究了高锰酸钾和粉末活性炭联用对臭味的去除效果。结果表明,高锰酸钾与粉末活性炭联用,对臭味的去除效果优于单独投加高锰酸钾或粉末活性炭;高锰酸钾与粉末活性炭同时投加或间隔投加,对臭味的去除效果无明显差异;在给水工艺投加量条件下,高锰酸钾与粉末活性炭联投,可有效避免沉后水的异色和锰含量超标;同时投加高锰酸钾0.5mg/L和粉末活性炭20mg/L,预处理20-30min后再混凝沉淀,对臭味强度等级为4的试验原水处理效果良好,沉后水的臭味强度等级降至0-1;同时投加高锰酸钾1.0mg/L和粉末活性炭30mg/L,预处理30min后再混凝沉淀和砂滤,对具有极强烈恶臭（臭味强度等级≥5）的试验原水处理效果良好,沉后水臭味强度等级降至1-2,滤后水臭味强度等级降至0-1。     

高锰酸钾与粉末活性炭联用去除饮用水中嗅味

针对太湖B支流水体发臭现象严重、采用常规工艺处理很难去除嗅味物质的情况，通过试验考察了单独投加高锰酸钾、单独投加粉末活性炭以及高锰酸钾与粉末活性炭联用三种方法对嗅味的去除效果。静态及生产性试验结果表明：高锰酸钾与粉末活性炭联用工艺的除嗅效果最好，当高锰酸钾投加量为0．5mg／L、粉末活性炭投加量为40mg／L时，沉后水的嗅阈值仅为5，去除率达到了98．8％，并且可节省粉末活性炭投量约20％。此外，高锰酸钾与粉末活性炭联用对藻类也有较好的去除效果。     

高锰酸钾-粉末活性炭联用去除原水中的嗅味

针对常规处理工艺难以解决东江原水发臭的问题,考察了高锰酸钾-粉末活性炭联用技术对水中嗅味的去除效果。结果表明,高锰酸钾一粉末活性炭联用对水中嗅味具有较好的去除效果,当氧化吸附时间为30min,高锰酸钾投加量为1．5mg/L,粉末活性炭投加量为40mg／L时,经混凝沉淀后水中的嗅味可由5级降至0级。此外,高锰酸钾和粉末活性炭联用对水中的有机物、浊度及锰也有明显的去除效果。     

水源突发性铊污染的去除试验研究

为了应对水厂可能存在的铊污染风险,本文研究了粉末活性炭吸附法、颗粒炭过滤法、高锰酸钾预氧化-混凝沉淀法对水中铊污染物的去除效果。试验结果表明：粉末活性炭吸附法对铊的去除效果不明显,投加50mg/L的粉末炭对铊的去除率仅为37%;颗粒活性炭可以将铊浓度为0.6μg/L的水样去除至低于0.1μg/L;高锰酸钾预氧化与混凝沉淀联用法效果最好,可以将1.0μg/L的铊去除至低于0.1μg/L。     

KMnO4与PAC联用预处理微污染源水的研究

为探寻微污染源水的预处理工艺,进行了高锰酸钾与活性炭联用去除运河水体中有机物、氨氮等污染物的试验研究.结果表明：在聚合硫酸铁、高锰酸钾、活性炭投加量分别为20、1.0、15 mg/L时,可将运河源水中的COD含量从113.6 mg/L降到9.66 mg/L,去除率达91.5%;氨氮含量从2.55 mg/L降到0.49 mg/L,去除率为80.8%,出水水质达到了Ⅱ类水源水标准.     

粉末活性炭对甲基对硫磷和对硫磷的去除研究

通过对粉末活性炭吸附特性的研究,探讨了活性炭工艺去除饮用水中甲基对硫磷和对硫磷有机磷农药的可行性。用Freundlich公式拟合吸附等温线的数据,并用来估算活性炭的吸附容量和最大投加量。试验结果表明,向甲基对硫磷、对硫磷浓度分别为0.22,0.06mg/L的配水中投加10mg/L粉末活性炭,吸附时间20min时两者的去除率为93.66%～98.11%。针对南方某水厂原水,试验所确定的活性炭最佳投加量为1.5～2.0mg/L。试验证明投加粉末活性炭是去除饮用水中甲基对硫磷和对硫磷的有效方法。     

组合预氧化强化生物炭滤池处理微污染原水

针对原水污染严重的实际情况,开展了以臭氧、高锰酸钾和粉末活性炭的组合预氧化工艺强化生物活性炭滤池去除嗅味、CODMn、氨氮等的生产性试验.当原水的CODMn和氨氮浓度分别为7.0、3.0 mg/L时,出水浓度分别为3.0、0.5 mg/L,且出水无嗅味.同时试验结果还表明,对CODMn的去除主要发生在预氧化过程中,生物活性炭滤池主要靠生物吸附和活性炭吸附去除CODMn.     

高锰酸盐复合药剂用于石油污染原水处理的研究

分析了高锰酸盐复合药剂(PPC)对石油的氧化性能,研究了PPC用于混凝时对石油的强化去除效果和PPC-粉末活性炭联用除油技术.结果表明:PPC对石油有较好的氧化性能,去除率达35%以上,PPC在原水中性条件下,对石油的处理效果最佳;原水石油低倍超标(<0.5mg/L)时,原水中性条件下投加1.5 mg/L PPC和20 mg/L聚合氯化铝(PAC)可保证出水水质达标;PPC-粉末活性炭吸附联合技术对石油的最大可处理污染浓度为5.5 mg/L.     

预处理强化生物活性炭工艺研究

研究了不同水处理组合工艺的除污染效能,包括化学预处理、常规处理、生物活性炭或臭氧生物活性炭技术的联用。试验结果表明,臭氧预氧化、高锰酸盐复合药剂（PPC）预氧化均能强化生物活性炭或臭氧生物活性炭工艺对各项指标的去除,可提高对浊度、UV254、CODMn的去除率;PPC预氧化与生物活性炭联用技术可强化AOC、BDOC的去除效果,达到生物稳定性的控制要求,是适合我国水厂改造的水处理技术。     

Simultaneous removal of phenol and ammonia by an activated sludge process with cross-flow filtration

Attempts were made for removing ammonia from synthetic wastewater under the presence of phenol, which is inhibitory to nitrification, by using a single-stage activated sludge process with cross-flow filtration. Activated sludge biomass which had been acclimated with phenol for over 15 years was used for the inoculum, and synthetic wastewater was continuously supplied to the process retaining biomass at 8000 mg VSS l(-1). Phenol was completely removed, and ammonia was simultaneously nitrified to nitrate; nitrification rate reached 200 mg N l(-1) d(-1) when phenol was removed at a rate up to 300 mg l(-1) d(-1). It was observed that 0-13% of the ammonia was removed via denitrification. Intermittent aeration enhanced the denitrification rate to 160 mg N l(-1) d(-1) by utilizing phenol. and approximately 24% of the denitrified nitrogen was recovered as nitrous oxide. Methanol, which is the most commonly used electron donor in conventional nitrogen removal processes, did not enhance the denitrification rate of the phenol-acclimated activated sludge used in this study, however phenol did. The results suggest that this process potentially works as a space- and energy-saving nitrogen removal process by utilizing substances inhibitory to nitrifiers as electron donors for denitrification.     

Biodegradation and effect of formaldehyde and phenol on the denitrification process

Formaldehyde and phenol biodegradation during the denitrification process was studied at lab-scale, first in anoxic batch assays and then in a continuous anoxic reactor. The biodegradation of formaldehyde (260 mgl(-1)) as single carbon source and at phenol concentrations ranging from 30 to 580 mgl(-1) was investigated in batch assays, obtaining an initial biodegradation rate around 0.5g CH(2)OgVSS(-1)d(-1). With regard to phenol, its complete biodegradation was only observed at initial concentrations of 30 and 180 mgl(-1). The denitrification process was inhibited at phenol concentrations higher than 360 mgl(-1). Studies were also done using a continuous anoxic upflow sludge blanket reactor in which formaldehyde removal efficiencies above 99.5% were obtained at all the applied formaldehyde loading rates, between 0.89 and 0.14g COD (CH(2)O)l(-1)d(-1). The phenol loading rate was increased from 0.03 to 1.3g COD (C(6)H(6)O)l(-1)d(-1). Phenol removal efficiencies above 90.6% were obtained at phenol concentrations in the influent between 27 and 755 mgl(-1). However, when the phenol concentration was increased to 1010 mgl(-1), its removal efficiency decreased. Denitrification percentages around 98.4% were obtained with phenol concentrations in the influent up to 755 mgl(-1). After increasing phenol concentration to 1010 mgl(-1), the denitrification percentage decreased because of the inhibition caused by phenol.     

Continuous electrochemical treatment of phenolic wastewater in a tubular reactor

The electrochemical treatment of phenolic wastewater in a continuous tubular reactor, constructed from a stainless steel tube with a cylindrical carbon anode at the centre, was investigated in this study, being first in literature. The effects of residence time on phenol removal was studied at 25 degrees C, 120 g l(-1) electrolyte concentration for 450 and 3100 mg l(-1) phenol feed concentrations with 61.4 and 54.7 mA cm(-2) current densities, respectively. The change in phenol concentration and pH of the reaction medium was monitored in every run and GC/MS analyses were performed to determine the fate of intermediate products formed during the electrochemical reaction in a specified batch run. During the electrolysis mono, di- and tri-substituted chlorinated phenol products were initially formed and consumed along with phenol thereafter mainly by polymerization mechanism. For 10 and 20 min of residence time phenol removal was 56% and 78%, respectively, with 450 mg l(-1) phenol feed concentration and above 40 min of residence time all phenol was consumed within the column. For 1, 1.5, 2 and 3h of residence time, phenol removal achieved was 42%, 71%, 81% and 98%, respectively, at 3100 mg l(-1) phenol feed concentration. It is noteworthy that more than 95% of the initial phenol was converted into a non-passivating polymer without hazardous end products in a comparatively fast and energy-efficient process, being a safe treatment.     

Electro‐oxidation of phenol in petroleum wastewater using a novel pilot‐scale electrochemical cell with graphite and stainless‐steel electrodes

This work investigated the removal of phenol from petroleum wastewater by the electro‐oxidation process. The experimental design was developed on a pilot‐scale electro‐oxidation system equipped with a cylindrical shape of graphite electrodes as an anode and stainless‐steel electrodes as a cathode. An initial study was performed based on operating variables such as current density and time on real petroleum wastewater. The optimum conditions were obtained as a current density of 3 mA/cm² and time 15 min. Under these applied optimum conditions, complete phenol removal from an initial concentration of about 6.8 mg/L was achieved. Also, 50–60% removal of organic matter in terms of chemical oxygen demand (COD) and biological oxygen demand (BOD). The removal of organic matter using electro‐oxidation requires a long reaction time. Also, the economic study indicated that the energy consumption was determined to be 0.79 kWh/m³ and the operating cost was 0.051 $/m³ which is very economical compared with conventional methods.     

Phenol biodegradation and its effect on the nitrification process

Phenol biodegradation under aerobic conditions and its effect on the nitrification process were studied, first in batch assays and then in an activated sludge reactor. In batch assays, phenol was completely biodegraded at concentrations ranging from 100 to 2500 mg l(-1). Phenol was inhibitory to the nitrification process, showing more inhibition at higher initial phenol concentrations. At initial phenol concentrations above 1000 mg l(-1), the level of nitrification decreased. In the activated sludge reactor, the applied ammonium loading rate was maintained at 140 mg N-NH(4)(+)l(-1)d(-1) (350 mg N-NH(4)(+)l(-1)) during the operation time. However, the applied organic loading rate was increased stepwise from 30 to 2700 mg COD l(-1)d(-1) by increasing the phenol concentration from 35 up to 2800 mg l(-1). High phenol removal efficiencies, above 99.9%, were maintained at all the applied organic loading rates. Ammonium removal was also very high during the operation period, around 99.8%, indicating that there was no inhibition of nitrification by phenol.     

Biodegradation of phenol by Synechocystis sp. in media including triacontanol hormone

Phenol removal levels of Synechocystis sp. were investigated in BG11 media with 10 mg/L triacontanol (TRIA) and without it to test whether the hormone could increase the removal efficiency by increasing biomass. The assays were performed to determine the effect of light on degradation, in media with 119.0–492.8 mg/L phenol under light and dark conditions. At increasing phenol concentrations, the degradation ranged between 98.5 and 100% regardless of a dark or a light condition. Experiments were carried out under light to determine the optimum pH for effective degradation. Optimum pH was found to be 6.5 at 200 mg/L phenol with or without TRIA. Phenol degradation was investigated in the 120.2–826.9 mg/L range. Although 377.4 mg/L phenol was completely degraded in hormone controls within 120 h, degradation was increased by TRIA, and the process was completed in 96 h. These data suggest that Synechocystis sp. has potential for use in the treatment of wastewaters containing phenol.     

Bioadsorbent Hura Crepitans for the removal of phenol from solution

The use of Hura crepitans (sandbox tree) seed as a biomass adsorbent was studied for the removal of phenol from aqueous solutions before extraction (HC) and after extraction (EHC) with hexane and methanol. The surface chemistry of HC and EHC was characterized by using the Boehm titration and pH drift while the removal of phenol from solution was monitored by using high performance liquid chromatography (HPLC). Decrease in the pH of solutions led to a significant increase in the adsorption capacity of HC and EHC. The linear regression of the experimental data showed that the Freundlich model fitted well with the values of adsorption capacity equal to 121 mmol/g for HC and 85 mmol/g for EHC, and the pseudo-second order kinetic model best described the adsorption process for HC and EHC. The experimental data indicated that the seed of Hura crepitans could be effectively used as an adsorbent for the removal of phenol from aqueous solutions.     

A comparative study on treatment of wastewaters with various biodegradability and various pH values using single‐chamber microbial fuel cells

This work assessed the performance of a single‐chamber microbial fuel cell (MFC) with various substrates. Primary settled domestic wastewaters were used to simulate wastewaters of high biodegradability; while phenol‐based wastewaters and benzene‐based wastewaters were used to simulate wastewaters of low biodegradability. Experiments were performed at initial pH values of 6, 7 and 8. The maximum voltage production, power density and removal of substrate were obtained using primary settled domestic wastewater, whereas the lowest values were obtained using phenol‐based wastewater. The maximum chemical oxygen demand removal efficiency, phenol removal efficiency and benzene removal efficiency were 80.8, 63.3 and 77.8%, respectively. The performance of the MFC was enhanced by increasing the influent pH. The lowest coulombic efficiencies were obtained from phenol‐based wastewater and benzene‐based wastewater, which indicated that electrogenic bacteria were not the primary microorganisms responsible for the biodegradation of low biodegradable wastewater.     

Optimization of phenol removal from wastewater by activation of persulfate and ultrasonic waves in the presence of biochar catalyst modified by lanthanum chloride

In this paper, the effects of phenol concentration, pH, catalyst dose, persulfate concentration, temperature and contact time on the phenol removal from wastewater by activation of persulfate (S₂O₈^?2) in the presence of biochar modified by lanthanum chloride and ultrasonic waves (US) are optimized. Experimental design and optimization were carried out by response surface methodology. The optimum conditions for the maximum phenol removal were obtained pH of 4, phenol concentration of 86 mg/L, catalyst dose of 43 mg/L, persulfate concentration of 86 mg/L, temperature of 41 °C and contact time of 63 min. The optimum phenol removal from synthetic wastewater was attained 97.68%. Phenol removal by the mentioned system was fitted with the first‐order kinetic model. The combination of the ingredients of ‘S₂O₈^?2/US/Biochar‐LaCl₃’ system had a synergistic effect on the phenol removal.     

Optimization of the reaction conditions for enzymatic removal of phenol from wastewater in the presence of polyethylene glycol

The effect of the additive, polyethylene glycol (PEG), on the horseradish peroxidase (HRP) catalysed removal of phenol from wastewater has been studied over the phenol concentration range of 1–10 mM (0.1–1.0 g/l). The optimum pH, HRP concentration, PEG concentration and the molar ratio of hydrogen peroxide and phenol have been investigated in the presence of PEG at room temperature in order to achieve the maximum phenol removal efficiency with the minimum cost. The effect of concentrations of HRP and PEG on reaction time was also investigated. Experimental results showed that the addition of PEG had significant protective effect on the activity of HRP. The amount of peroxidase required was reduced 40- and 75-fold less than that required without PEG for 1 and 10 mM phenol solutions, respectively. The higher the phenol concentration, the more effective was the addition of PEG. In the presence of PEG, the optimum pH is 8.0 and the optimum molar ratio of hydrogen peroxide and phenol is around 1.0. The minimum doses of HRP and PEG required for at least 95% removal were determined for several phenol concentrations and two empirical models are proposed to predict the minimum HRP and PEG doses required for 95% removal over the entire phenol concentration range of 1–10 mM. Under the optimum reaction conditions described above, the reaction times for at least 95% removal from 1 and 10 mM phenol solutions were 5 and 3 h, respectively. An increase in HRP concentration significantly reduced the reaction time; however, an increase in PEG concentration showed negligible influence.