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1.
The efficiency of denitrification and enhanced biological phosphorus removal in biological nutrient removal activated sludge systems is strongly dependent on the availability of appropriate carbon sources. Due to high costs of commercial compounds (such as methanol, ethanol, acetic acid, etc.) and acclimation periods (usually) required, the effective use of internal substrates is preferred. The aim of this study was to determine the effects of slowly biodegradable compounds (particulate and colloidal), as internal carbon sources, on denitrification, phosphate release/uptake and oxygen utilization for a full-scale process mixed liquor from two large wastewater treatment plants located in northern Poland. Since it is difficult to distinguish the effect of slowly biodegradable substrate in a direct way, a novel procedure was developed and implemented. Four types of one- and two-phase laboratory batch experiments were carried out in two parallel reactors with the settled wastewater without pre-treatment (reactor 1) and pre-treated with coagulation–flocculation (reactor 2). The removal of colloidal and particulate fractions resulted in the reduced process rates (except for phosphate release). The average reductions ranged from 13 % for the oxygen utilization rate during the second phase of a two-phase experiment (anaerobic/aerobic), up to 35 % for the nitrate utilization rate (NUR) during the second phase of a conventional NUR measurement.  相似文献   

2.
In this study, kinetics of biological carbon, nitrogen, and phosphorous removal from a synthetic wastewater in an integrated rotating biological contactor-activated sludge system was investigated. The experimental data obtained from varying four significant independent factors viz., hydraulic retention time, chemical oxygen demand for nitrogen to phosphorus ratio, internal recirculation from aerobic to anoxic zone and disks rotating speed were used for the process kinetic modeling. In order to obtain the bioprocess kinetic coefficients, Monod, first-order and Stover?CKincannon models were employed. As a result, Monod and Stover?CKincannon models were found to be the appropriate models to describe the bioprocess in the rotating biological contactor-activated sludge system as the determination coefficient for the first-order model obtained less than 0.79. According to the Monod model, growth yield, microbial decay rate, maximum specific biomass growth rate, and half-velocity constant coefficients were found to be 0.712?g VSS/g COD, 0.008/d, 5.54/d and 55?mg COD/L, respectively. From Stover?CKincannon model, the maximum total substrate removal rate constant and half-velocity constant were determined as 15.2, 10.98, 12.05?g/L?d and 14.78, 7.11, 6.97?mg/L for chemical oxygen demand, nitrogen and phosphorus removal, respectively. The kinetic parameters determined in this study can be used to improve the design and operation of the biological contactor-activated sludge system in full scale.  相似文献   

3.
In this research, a novel laboratory scale anaerobic/upflow sludge blanket filtration combined bioreactor was designed and operated to improve the efficiency of the upflow sludge blanket filtration process for the simultaneous removal of phosphorus and nitrogen from wastewater. The anaerobic/upflow sludge blanket filtration technique was developed by adding an anaerobic reactor to its influent and operated by varying the main process parameters in order to gain the optimum conditions. The results showed that biological removal efficiency of nitrogen and preservation of sludge blanket strongly depend on wastewater characteristics, hydraulic retention time, sludge age and process controlling parameters. The combined bioreactor performed a total nitrogen removal efficiency of 96.6 % with the sludge age of 25 days, total hydraulic retention time of 24 h and optimum “chemical oxygen demand/nitrogen/phosphorus” ratio of 100/ 5/1. This ratio also improved the compaction quality of sludge blanket in the upflow sludge blanket filtration clarifier. The average specific nitrification and denitrification rates occurred during the process can be expressed as 4.43 mg NOx-N produced/g VSS.d and 5.50 mg NOx-N removed/g VSS.d at the optimum ratio, respectively. To avoid sludge rising due to denitrification process, the optimum total hydraulic retention time of 16 to 24 h was achieved based on the effluent quality. This study suggested that the anaerobic/upflow sludge blanket filtration bioreactor at the optimum operational conditions can be an effective process for removal of nutrients from municipal wastewater.  相似文献   

4.
This paper reports the results of the treatment of a yarn dyeing effluent using an integrated biological–chemical oxidation process. In particular, the biological unit was based on a sequencing batch biofilter granular sludge reactor (SBBGR), while the chemical treatment consisted of an ozonation step. Biological treatment alone was first performed as a reference for comparison. While biological treatment did not produce an effluent for direct discharge, the integrated process assured good treatment results, with satisfactory removal of chemical oxygen demand (up to 89.8 %), total nitrogen (up to 88.2 %), surfactants (up to 90.7 %) and colour (up to 99 %), with an ozone dose of 110 mg of ozone per litre of wastewater. Biomass characterization by fluorescence in situ hybridization has revealed that filamentous bacteria represented about 20 % of biomass (coherently with high sludge volume index values); thanks to its special design, SBBGR guaranteed, however, stable treatment performances and low effluent suspended solids concentrations, while conventional activated sludge systems suffer from sludge bulking and even treatment failure in such a condition. Furthermore, biomass characterization has evidenced the presence of a shortcut nitrification–denitrification process.  相似文献   

5.
吗啉废水的生化处理工艺   总被引：2，自引：0，他引：2  
以含有吗啉、甲基吗啉的高浓度有机废水为研究对象,提出了曝气吹脱-吸附-生物处理的联合工艺,并在室内进行了小试实验。结果表明：原废水经过2次曝气吹脱后,ρ(NH3-N)从62 500 mg/L降为431 mg/L,ρ(COD)从50 840 mg/L降为26 051 mg/L。通过吸附实验,ρ(COD)从26 051 mg/L降为2 769 mg/L,ρ(NH3-N)从412 mg/L降为134 mg/L。在生物处理室内小试实验中,采用了活性污泥反应器与曝气生物滤池相结合的处理工艺。在活性污泥反应系统中,当废水pH为7.5、ρ(DO)为4.3 mg/L、水力停留时间为30 h时,COD的去除率最高,可以达到83.1%。在曝气生物滤池中,当ρ(DO)为3.3 mg/L时,COD去除率最高,达到55.8%。在生物处理的最佳参数条件下进行连续监测,当进水ρ(COD)为2 769 mg/L、出水ρ(COD)平均值为387 mg/L时,COD去除率可达到85.9%。吗啉废水经过此联合工艺的处理,ρ(COD)从50 840 mg/L降为387 mg/L。  相似文献   

6.
通过对曝气系统的调节,微压流化式复合生物反应器（MP-FHBR）内可以实现好氧区和缺氧区共存,利用这一特点和MP-FHBR中同时存在的活性污泥﹑悬浮生物膜复合生物体系,进行了同步脱氮的试验研究。结果表明,MP-FHBR在好氧-缺氧条件下,实现了同步脱氮过程,TN和COD的平均去除率分别达到77.5%和98.3%。降低DO质量浓度使反应器内形成完全缺氧环境,对MP-FHBR同步脱氮效果没有显著影响,但会降低系统去除COD的效果;而提高DO质量浓度使反应器内形成完全好氧环境,MP-FHBR同步脱氮效果显著下降。在一定范围内提高进水COD/TN有利于提高MP-FHBR同步脱氮效果,COD/TN 由2升高到10,TN平均去除率由58.4%提高到78.8%,而继续提高COD/TN对系统同步脱氮效果的影响并不明显。在反应器允许的条件下,提高污泥质量浓度(MLSS)有利于提高系统反硝化脱氮效果,TN去除率随MLSS的增加而提高。  相似文献   

7.
This review carries out a comparative study of advanced technologies to design, upgrade and rehabilitate wastewater treatment plants. The study analyzed the relevant researches in the last years about the moving bed biofilm reactor process with only attached biomass and with hybrid biomass, which combined attached and suspended growth; both could be coupled with a secondary settling tank or microfiltration/ultrafiltration membrane as a separation system. The physical process of membrane separation improved the organic matter and NH4 +-N removal efficiencies compared with the settling tank. In particular, the pure moving bed biofilm reactor–membrane bioreactor showed average chemical oxygen demand, biochemical oxygen demand on the fifth day and total nitrogen removal efficiencies of 88.32, 90.84 and 60.17%, respectively, and the hybrid moving bed biofilm reactor–membrane bioreactor had mean chemical oxygen demand, biochemical oxygen demand on the fifth day and total nitrogen reduction percentages of 91.18, 97.34 and 68.71%, respectively. Moreover, the hybrid moving bed biofilm reactor–membrane bioreactor showed the best efficiency regarding organic matter removal for low hydraulic retention times, so this system would enable the rehabilitation of activated sludge plants and membrane bioreactors that did not comply with legislation regarding organic matter removal. As the pure moving bed biofilm reactor–membrane bioreactor performed better than the hybrid moving bed biofilm reactor–membrane bioreactor concerning the total nitrogen removal under low hydraulic retention times, this system could be used to adapt wastewater treatment plants whose effluent was flowed into sensitive zones where total nitrogen concentration was restricted. This technology has been reliably used to upgrade overloaded existing conventional activated sludge plants, to treat wastewater coming from textile, petrochemical, pharmaceutical, paper mill or hospital effluents, to treat wastewater containing recalcitrant compounds efficiently, and to treat wastewater with high salinity and/or low and high temperatures.  相似文献   

8.
Endocrine disrupting chemicals are discharged into the environment mainly through wastewater treatment processes. There is a need for better understanding of the fate of these compounds in the unit processes of treatment plant to optimise their removal. The fate of oestrone, 17β-estradiol, 17α-ethinyestradiol and nonylphenol in the unit processes of full scale wastewater treatment plants in the UK, including activated sludge plant, oxidation ditch, biofilter and rotating biological contactor were investigated. The overall removal efficiencies of all the compounds ranged from 41 %to 100%. The removals were predominantly during the secondary biological treatment with the rates of removal related to the nitrification rates and the sludge age. The removal efficiency of the treatment processes were in the order activated sludge > oxidation ditch > biofilter > rotating biological contactors. Activated sludge plant configured for biological nutrient removal showed better removal of the endocrine disrupting chemicals compared to conventional activated sludge plant effluents. Tertiary treatment was also significant in the removal process through solids removal. Overall mechanisms of removal were biodegradation and sorption unto sludge biomass. Phytoremediation was also significant in the removal processes. The endocrine disrupting chemicals persisted in the anaerobic sludge digestion process with percentage removals ranging fro 10–48 %. Sorption of the endocrine disrupting chemicals onto the sludge increased with increasing values for the partitioning coefficients and the organic carbon contents of the sludge.  相似文献   

9.
The upflow anaerobic sludge blanket process followed by the biological aerated filter process was employed to improve the removal of color and recalcitrant compounds from real dyeing wastewater. The highest removal efficiency for color was observed in the anaerobic process, at 8-h hydraulic retention time, seeded with the sludge granule. In the subsequent aerobic process packed with the microbe-immobilized polyethylene glycol media, the removal efficiency for chemical oxygen demand increased significantly to 75 %, regardless of the empty bed contact time. The average influent non-biodegradable soluble chemical oxygen demand was 517 mg/L, and the average concentration in effluent from the anaerobic reactor was 363 mg/L, suggesting the removal of some recalcitrant matters together with the degradable ones. The average non-biodegradable soluble chemical oxygen demand in effluent from the aerobic reactor was 87, 93, and 118 mg/L, with the removal efficiency of 76, 74, and 67 %, at 24-, 12-, and 8-h empty bed contact time, respectively. The combined anaerobic sludge blanket and aerobic cell-entrapped process was effective to remove the refractory compounds from real dyeing wastewater as well as in reducing organic loading to meet the effluent discharge limits. This integrated process is considered an effective and economical treatment technology for dyeing wastewater.  相似文献   

10.
One of the technologies used for wastewater nitrogen removal consists in simultaneous nitrification–denitrification. The low microbial growth rate and the low availability of organic material for the denitrification stage make it necessary to study new operational conditions and the use of microbial supports. The aim of this study was to evaluate the operational behavior of a simultaneous nitrification–denitrification process in a sequential batch reactor utilizing zeolite as a biomass support and step-feed strategy. Two reactors of 2 L were used, one with zeolite and another without zeolite, both operated at constant temperature (31 °C), varying nitrogen loading rate (NLR) from 0.041 to 0.113 kg total Kjeldahl nitrogen (TKN/m3/day). After 209 days, removals higher than 86 and 96 % in nitrogen compounds and organic matter were obtained, respectively. There was not accumulation of nitrate and nitrite in any case; this means that there was a simultaneous nitrification–denitrification in the reactors. The incorporation of zeolite in the system held higher concentration of biomass in the reactor; this led to reduce start-up to 21 days and to improve 11.31 % removal kinetic. The use of a step-feed strategy prevents events of inhibition by substrate, even duplicating tolerance to higher NLR for the same operation time.  相似文献   

11.
A grouped mesocosm study was conducted with different water holding capacities and conditions to determine nutrient removal efficiency using floating wetland macrophytes. Different scenarios were created by changing water depth, littoral vegetation, sorption media and area coverage to observe how they affect nutrient removal efficiencies. Plant species were screened and selected based on the literature, local availability and previously performed microcosm studies. Sorption media were warped using geotextile filter fostering microbial colonization in the rhizospheric zone to enhance denitrification and plant growth. Water quality parameters included total nitrogen, total phosphorus, orthophosphate, nitrate?Cnitrogen and ammonia?Cnitrogen in addition to in situ parameters such as pH, dissolved oxygen, temperature and chlorophyll-a. Composite samples across several locations were collected periodically to understand the spatial distribution or aggregation of nutrients. After 3?months of water quality monitoring, plants were analyzed for tissue nutrient concentrations, and the average uptake rate was calculated as 36.39 and 1.48?mg?m?2?day?1 for nitrogen and phosphorus, respectively, by the floating treatment wetland system. Finally, considering the higher nutrient aggregation in the rhizospheric zone, the removal rate with 5?% area coverage and water quality improvement by littoral zone, the optimized design, placement and maintenance of the whole system were recommended.  相似文献   

12.
In this research, physical, chemical and biological treatability of Tehran solid waste leachate was studied. Results indicate that the amount of COD for the fresh raw leachate of Tehran is equal to 66,608 mg/l. The leachate is transferred to an equalization tank for storage and pH control process. After neutralization, leachate is introduced to an up flow and down flow anaerobic reactor. The effluent of anaerobic reactor is conducted to a sequencing batch reactor. Sequence batch reactor (SBR) effluent was pumped in to sand and activated carbon filters, after chemical coagulation and clarification. Results showed that anaerobic reactor with detention time of 3 days had a 35% COD removal and increasing the detention time to 4.5 days would improve the COD removal to 45%. Nutrient adjustment with phosphorus and nitrogen increased the initial 23% efficiency of sequence batch reactor to 44%. The effluent COD of SBR reactor was 21,309 mg/l. Recycling of aerobic reactor effluent with incoming feed to anaerobic reactor reduced the anaerobic reactor influent COD to 20,000 mg/l and this caused 53% and 57% COD removal in the anaerobic and aerobic effluent, respectively. The total systems COD performance increased to 80% and SBR effluent COD eventually reduced to 4,000 mg/l. Coagulation, flocculation and sedimentation processes were practiced to make the 4,000 mg/l effluent COD comply with environmental standards of Iran. The optimum coagulant found to be ferric chloride with the dosage of 50 mg/l at pH of 12, which reduced 10% of COD to an amount of 3,676 mg/l. The effluent was stored in a tank and then pumped in to pressure sand filter and afterwards to activated carbon filter. The COD removal was three and 90% for sand and activated carbon filters, respectively. The total process reduced the remaining COD to 36 mg/l, which is in compliance with environmental standards of Iran.  相似文献   

13.
Two simulation tools for industrial wastewater treatment plan using a biofilm activated sludge process are contrasted in this paper; biofilm activated sludge consists of moving bed biofilm reactor followed by conventional activated sludge. Wastewater treatment simulator software (BioWin) and general chemical engineering process software with an integrated mathematical model (Aspen Custom Modeler) are used as simulation tools under different configurations of wastewater treatment plant and influent conditions. The simulated results using BioWin do not fit the experimental concentrations of chemical oxygen demand and total suspension solids from a full-scale biofilm activated sludge process for cellulose and viscose plant wastewaters; however, using Aspen Custom Modeler the simulated results fit adequately. The differences between the two software are explained by the consideration or not of the predation and hydrolysis phenomena in the mathematical model. The trade-off between the models complexity and the goodness in the adjustment of the results shows that in the biofilm activated sludge process the inclusion of predation in the mathematical model becomes essential. The optimization tool included in Aspen Custom Modeler is selected to optimize the operational conditions using three objective functions: minimization of nutrients in the effluent, minimization of sludge production and maximization of excess sludge concentration. Operating cost of the process can be reduced up to 10% considering the optimal conditions proposed by the optimization tool.  相似文献   

14.
Two sets of lab-scale sequencing batch reactors (SBR), i.e., control SBR and SBR using zeolite as carrier (zeo-SBR), were applied to assess nitrogen removal efficiency. The test results revealed that zeolite powder added in SBR could improve its performance. Due to the combination of zeolite adsorption for NH4 +–N and enhanced simultaneous nitrification and de-nitrification (SND), a higher removal ratio of ammonia nitrogen in wastewater was observed in the test reactor, and the introduction of zeolite powder was helpful to inhabit sludge bulging comparing with the control SBR, in other words, activated sludge immobilized by zeolite powder could remove NH4 +–N, COD, and PO4 significantly in a shorter cycle time. Applied two hydraulic retention times (HRTs) showed that the nitrogen and phosphorus removal could be improved while adapting to load variations.  相似文献   

15.
在上流式好氧颗粒污泥床反应器中, 以厌氧颗粒污泥和好氧絮状活性污泥为接种泥, 采用人工配制的模拟废水, 成功培养出性能优异的好氧颗粒污泥.反应器内污泥浓度稳定在5g/L左右, 颗粒污泥粒径为0.5~2.0mm, 当进水COD为2000mg/L, 容积负荷为4.8kg/(m3·d)时, 系统对COD的去除率稳定在96%以上.通过扫描电镜观察, 好氧颗粒污泥是层状结构, 表面有大量丝状菌缠绕, 内部有短杆菌和空穴存在.逐步提高制药废水在进水中的比例, 经过47d的培养, 生物制药废水完全取代模拟废水, 系统对COD、NH3-N、TP的去除率分别稳定在90%、90%和70%以上.   相似文献   

16.
A considerable increase in nitrate concentration in groundwater has been observed in many countries. This research focuses on nitrate removal using biodegradable snack ware (BSW) as both carbon source and biofilm support for denitrifiers. The denitrification efficiency of a laboratory-scale denitrification reactor packed with BSW was examined in a low-temperature condition. The nitrate removal efficiency supported by BSW decreased to approximately 40% at 12°C from nearly 100% at 25°C with 50?mg/L of nitrate-nitrogen in the influent and 2?h of hydraulic retention time (HRT). The complete nitrate removal was obtained when nitrate-nitrogen concentration was no more than 15?mg/L at 2?h of HRT and at 12°C. If the initial concentration of nitrate-nitrogen was 50?mg/L, 5?h of HRT was needed for the complete nitrate removal. Nitrite concentration in the treated water decreased evidently as HRT was increased from 2 to 5?h, or as nitrate-nitrogen concentration in the influent decreased to 15?mg/L from 50?mg/L. It was observed that varying HRT and nitrate concentration in the influent had no noticeable effect on dissolved organic carbon content in the effluent under the experimental conditions. This study indicated that the complete nitrate removal could be achieved readily even at 12°C using BSW as carbon source by changing HRT or the initial concentration of nitrate in the influent, which has some useful implications in environmental engineering practice.  相似文献   

17.
Landfill leachates are not adequately treated in traditional wastewater treatment plants, on account of their problematic peculiarities: i.e., dark colour, high concentration of recalcitrant pollutants and COD, and high toxicity. In this work, 19 biomasses (15 autochthonous and 4 allochthonous) were exploited in biosorption treatment for the remediation of a leachate (influent) and the effluent coming from the biological oxidation with activated sludge and nitrification–denitrification treatment. The effects of the initial pH, the biomass amount, and the medium for the biomass pre-culture were considered. The best configuration was: pH 5, 5 g L??1 biomass cultivated on STY medium. Eventually, the two most effective biomasses, Cunninghamella bertholletiae MUT 2861 and Aspergillus fumigatus MUT 4050, were used in consecutive 2 h cycles in a batch biosorption experiment. The effectiveness of the treatment decreased in subsequent cycles in terms of decolourisation (31–15%). COD, Cl?, SO42?, total N, and toxicity were removed mainly in the second cycle of treatment (up to ??36, ??12, ??15, ??17 and ??49%, respectively). The results suggest that the effluent toxicity was basically due to uncoloured substances, which were mainly removed after coloured molecules.  相似文献   

18.
Hybrid anaerobic baffled reactor for treatment of desizing wastewater   总被引：3，自引：3，他引：0  
Polyvinyl alcohol-containing desizing wastewater discharged within final textile wastewater has a great impact to the environment due to its poor biodegradability. An improved lab-scale hybrid anaerobic baffled reactor was developed to treat desizing wastewater. The modification was achieved by increasing the height of hybrid anaerobic baffled reactor and application of proper effluent recycle enabled to increase the ability of entrapping microbe-rich small particles in the reactor and prompted the formation of granules. The significant difficulty in hybrid anaerobic baffled reactor operation is the slow start-up procedure, which is crucial to the overall polyvinyl alcohol-containing desizing wastewater treatment. Therefore, the ability of a hybrid anaerobic baffled reactor, treating desizing wastewater, to achieve a prompt start-up was studied at lab-scale. Results showed that inoculated with anaerobic granular sludge and adoption of effluent recycle during start-up, the system demonstrated a good performance of polyvinyl alcohol removal efficiency (above 17.2 %) and satisfactory stability of pH and alkalinity in effluent (range around 7.4–8.0 and 700–920 mg/L, respectively) and the sludge appeared obviously granulation. Thus, the prompt start-up was achieved after 60 days. The start-up strategy used for this process has achieved its goals by creating an active microbial population. The improved lab-scale hybrid anaerobic baffled reactor proved to be an efficient reactor configuration for the treatment of desizing wastewater, which favored the prompt start-up of hybrid anaerobic baffled reactor. The results also provide evidence to modify the design of anaerobic baffled reactor to improve reactor performance.  相似文献   

19.
Wastewater treatment using moving bed membrane bioreactor technology was tested with real urban wastewater at a pilot plant, combining moving bed treatment as a biological process with hybrid biomass (suspended and fixed) and the advantages of a membrane separation system. The evolution of the kinetic constants of the hybrid biomass and organic matter removal were studied in a pilot plant under different operational conditions, by varying hydraulic retention time (HRT), mixed liquor suspended solids (MLSS) and temperature, and considering the attached biomass of the carrier and the dispersed biomass of the flocs to reproduce real treatment conditions. The rates of organic matter removal were 97.73 ± 0.81 % of biochemical oxygen demand (BOD5), 93.44 ± 2.13 % of chemical oxygen demand (COD), 94.41 ± 2.26 % of BOD5 and 87.62 ± 2.47 % of COD using 24.00 ± 0.39 and 10.00 ± 0.07 h of HRT, respectively. The influence of the environmental variables and operational conditions on kinetic constants was studied; it was determined that the most influential variable for the decay coefficient for heterotrophic biomass was HRT (0.34 ± 0.14 and 0.31 ± 0.10 days?1 with 10.00 ± 0.07 and 24.00 ± 0.39 h of HRT, respectively), while for heterotrophic biomass yield, this was temperature (0.61 ± 0.04 and 0.52 ± 0.06 with 10.00 ± 0.07 and 24.00 ± 0.39 h of HRT, respectively). The results show that introducing carriers in an MBR system provides similar results for organic matter removal, but with a lower concentration of MLSS.  相似文献   

20.
A mathematical model of the biological process occurring in a modified biofilm airlift suspension reactor is presented. When compared with a traditional wastewater treatment plant, a biofilm airlift suspension process has major advantages, such as higher oxygen levels in the bulk fluid and lower space requirements. The limited volumes obtained with this technique generally do not allow to reach the high times of contact required for an efficient removal of nitrogen that normally are characterized by a slower kinetics than carbonaceous compounds. To avoid this problem, supports for attached biomass growth were inserted in the reactor. Both physical and biological aspects were incorporated into the presented model to simulate the removal processes of the substrates. A sensitivity analysis was performed, and the model was validated using experimental results obtained at a lab-scale plant. This model can accurately estimate the removal rate in different boundary conditions providing the details of the water quality profiles through the reactor and in the attached biomass. The model thus represents a valid aid for design purposes and for the management of treatment plants that use these uncommon reactors. The model also provides the required hydraulic retention time for a complete nitrification and the appropriate recirculation ratio. The results have shown the full-scale applicability of this treatment due to its efficiencies coupled to the advantages of its low impact, low space requirement and low sludge production.  相似文献   

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