In this research, the quality of the wastewater discharged into the environment has been investigated. The effluent from solar desalination pond contains large amounts of TDS (3.68 grams per liter) and TH (6.50 grams ...In this research, the quality of the wastewater discharged into the environment has been investigated. The effluent from solar desalination pond contains large amounts of TDS (3.68 grams per liter) and TH (6.50 grams per liter). Since the use of filter is not economical in this case, three types of commercial coagulants such as aluminum sulfate, ferric chloride and ferric sulfide have been used in this study. The main parameters such as effectiveness of three inorganic coagulants, ammonium sulfate, ferric sulfate, and ferric chloride, which separately help to remove hardness, have been studied. According to the results, using laboratory test, 25/g of ferric sulfate as coagulant is best coagulant mass and the ratio of 4 to 3 for auxiliary coagulant (sodium carbonate and sodium hydroxide) to coagulant will be best ratio. Also, the mixing rate of 120 rpm in the first reactor will give the best mixing speed. These conditions will lead to 0.348 grams per liter of TDS, 0.345 grams per liter of TH and 0.195 grams per liter of calcium hardness and 300 micro Siemens electrical conductivity of the purified sample.展开更多
Anaerobic treatment model treats fish processing wastewater to be necessary for a small and medium factory that is very popular in Vietnam and other countries.Several techniques have been proposed.However,they are qui...Anaerobic treatment model treats fish processing wastewater to be necessary for a small and medium factory that is very popular in Vietnam and other countries.Several techniques have been proposed.However,they are quite expensive and hard to operate,especially in remote areas.In this study,the hydraulic retention times(HRT)including 3,5,and 7 hours with a various organic loading rate of 1.5 to 6.5 kg COD/m3/day were investigated.Biomass concentration as mix-liquor volatile suspended solid(MLVSS)in the model is at 6,000 to 9,000 mg/L.On the basis of the result the optimal HRT with a 4.0 kg COD/m3/day organic loading rate was 8 hours which BOD5,COD removal efficiency were 92.18,87.36 percent respectively.By the end of the optimal hydraulic retention times,the total methane gas volume as a by-product was collected with 2.6 liters.展开更多
Chinese traditional medicine wastewater, rich in macromolecule and easy to foam in aerobic biodegradation such as Glycosides, was treated by two identical bench-scale aerobic submerged membrane bioreactors (SMBRs) o...Chinese traditional medicine wastewater, rich in macromolecule and easy to foam in aerobic biodegradation such as Glycosides, was treated by two identical bench-scale aerobic submerged membrane bioreactors (SMBRs) operated in parallel under the same feed, equipped with the same electronic control backwashing device. One was used as the control SMBR (CSMBR) while the other was dosed with powdered activated carbon (PAC) (PAC-amended SMBR, PSMBR). The backwashing interval was 5 min. One suction period was about 90 min by adjusting preestablished backwashing vacuum and pump frequency. The average flux of CSMBR during a steady periodic state of 24 d (576 h) was 5.87 L/h with average hydraulic residence time (HRT) of 5.97 h and that of PSMBR during a steady periodic state of 30 d (720 h) was 5.85 L/h with average HRT of 5.99 h. The average total chemical oxygen demand (COD) removal efficiency of CSMBR was 89.29% with average organic loading rate (OLR) at 4.16 kg COD/(m^3.d) while that of PSMBR was 89.79% with average OLR at 5.50 kg COD/(m^3.d). COD concentration in the effluent of both SMBRs achieved the second level of the general wastewater effluent standard GB8978-1996 for the raw medicine material industry (300 mg/L). Hence, SMBR with electronic control backwashing was a viable process for medium-strength Chinese traditional medicine wastewater treatment. Moreover, the increasing rates of preestablished backwashing vacuum, pump frequency, and vacuum and flux loss caused by mixed liquor in PSMBR all lagged compared to those in CSMBR; thus the actual operating time of the PSMBR system without membrane cleaning was extended by up to 1.25 times in contrast with the CSMBR system, and the average total COD removal efficiency of PSMBR was enhanced with higher average OLR.展开更多
The advanced treatment using integrated Fenton's reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreat...The advanced treatment using integrated Fenton's reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB (upflow anaerobic sludge bed) and a SBR (sequencing batch reactor) process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry (GC-MS), mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton's reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2+=3:1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.展开更多
[ Objective ] The study aimed at treating wastewater treatment plant (WWTP) effluent by using bio-film reactor with filamentous bamboo as bio-carrier. [ Method] With the aid of a continuous flow reactor, a bio-film ...[ Objective ] The study aimed at treating wastewater treatment plant (WWTP) effluent by using bio-film reactor with filamentous bamboo as bio-carrier. [ Method] With the aid of a continuous flow reactor, a bio-film reactor using filamentous bamboo as bio-carrier was used to treat WWTP effluent with low C/N ratio, and the removal effects of CODc,, TN (total nitrogen), and NO3--N in the wastewater were analyzed.[ Result ] The average removal rates of CODcr, TN, and NO3- -N reached 47.7%, 23.6% and 34.5% when the C/N ratio of influent was around 2. In addi- tion, a stable bio-film was formed very well in the secondary effluent with low C/N ratio and hardly degradable organic pollutants. The pollutants could be removed effectively because of the excellent surface characteristics and compositions of filamentous bamboo. [ Conclusion] The research provides a new method to treat WWTP effluent with low C/N ratio.展开更多
Based on the experiments of utilization of garlic processing wastewater in a lotus pond, this study demonstrates that lotus pond wetlands have a remarkable ability to remove organic pollutants and decrease chemical ox...Based on the experiments of utilization of garlic processing wastewater in a lotus pond, this study demonstrates that lotus pond wetlands have a remarkable ability to remove organic pollutants and decrease chemical oxygen demand (CODCr), biochemical oxygen demand (BOD5), and suspended substances (SS) in garlic processing wastewater. Results also show evident effects of lotus roots on absorption of NH3-N. The pH value in a lotus pond with wastewater discharged was relatively stable. The water quality in the lotus pond reached the class Ⅱ emission standard, according to the Integrated Wastewater Discharge Standard (GB8978-1996), seven days after pretreated garlic processing wastewater had been discharged into the lotus pond. Garlic processing wastewater irrigation does not produce pollution in the pond sediment and has no negative effect on the growth of lotus roots. Due to utilization of garlic processing wastewater, the output of lotus roots increased by 3.0% to 8.3%, and the quality of lotus roots was improved. Therefore, better purification and utilization results can be achieved.展开更多
A laboratory scale test was conducted in a combined membrane process (CMP) with a capacity of 2.91 m3/d for 240 d to treat the mixed wastewater of humidity condensate, hygiene wastewater and urine in submarine cabin...A laboratory scale test was conducted in a combined membrane process (CMP) with a capacity of 2.91 m3/d for 240 d to treat the mixed wastewater of humidity condensate, hygiene wastewater and urine in submarine cabin during prolonged voyage. Removal performance of chemical oxygen demand (COD), ammonia nitrogen (NH4^+-N), turbidity and anionic surfactants (LAS) was investigated under different conditions. It was observed that the effluent COD, NH4^+-N, turbidity and LAS flocculated in ranges of 0.19-0.85 mg/L, 0.03-0.18 mg/L, 0.0-0.15 NTU and 0.0-0.05 mg/L, respectively in spite of considerable fluctuation in corresponding influent of 2120-5350 mg/L, 79.5-129.3 mg/L, 110-181.1NTU and 4.9-5.4 mg/L. The effluent quality of the CMP could meet the requirements of mechanical water and hygiene water according to the class I water quality standards in China (GB3838-2002). The removal rates of COD, NH4^+-N, turbidity and LAS removed in the MBR were more than 90%, which indicated that biodegradation is indispensable and plays a major role in the wastewater treatment and reuse. A model, built on the back propagation neural network (BPNN) theory, was developed for the simulation of CMP and produced high reliability. The average error of COD and NH4^+-N was 5.14% and 6.20%, respectively, and the root mean squared error of turbidity and LAS was 2.76% and 1.41%, respectively. The results indicated that the model well fitted the laboratory data, and was able to simulate the removal of COD, NH4^+-N, turbidity and LAS. It also suggested that the model proposed could reflect and manage the operation of CMP for the treatment of the mixed wastewaters in submarine.展开更多
The presence of sulfonamide antibiotics in aquatic environments has received increasing attention in recent years.Sulfadiazine(SD),a widely used heterocyclic sulfonamide pharmaceutical,has entered into the receiving w...The presence of sulfonamide antibiotics in aquatic environments has received increasing attention in recent years.Sulfadiazine(SD),a widely used heterocyclic sulfonamide pharmaceutical,has entered into the receiving water body.In this paper,gamma rays are used to irradiate samples of sulfadiazine antibiotics-containing wastewater.The results demonstrate that SD can be effectively degraded by irradiation,but the mineralization degree of SD(in terms of TOC) is not as efficient as the SD degradation.The addition of Fe^(2+) can significantly enhance the SD degradation and mineralization through the generation of hydroxyl radical by catalytic decomposition of H_2O_2 from water radiolysis.Ion chromatography analysis indicates that sulfate ions(SO_4^(2-)) and formate(HCOO^-) are the main intermediate products.Gamma irradiation is a promising technology for removing low-concentration antibiotics from water and wastewater.展开更多
A flexible fibre biofilm reactor was developed for treatment of organic wastewaters.The hydrodynamic characteristics and mass transfer coefficients of oxygen were studied and compared with those of the conventional ac...A flexible fibre biofilm reactor was developed for treatment of organic wastewaters.The hydrodynamic characteristics and mass transfer coefficients of oxygen were studied and compared with those of the conventional activated sludge processes.Tracer experiments were performed to obtain the residence time distributions of the reactors.The results indicated that both reactors could be treated as mixed flow reactors.The effects of flow rates of water and air on the overall mass transfer coefficient of oxygen were investigated,and the correlations between the mass transfer coefficient and the ratio of flow rates were obtained.Compared to the conventional activated sludge reactor,the mass transfer coefficients in the flexible fibre reactor were similar to but slightly lower,and less sensitive to the variation in the ratio of flow rates.It indicated that the fibre packing in the reactor hindered the oxygen transfer to some extent.展开更多
The study was conducted to characterize and perform laboratory-scale treatment of municipal drainage wastewater of Khulna, Bangladesh. Wastewater samples were collected from three different points of existing urban dr...The study was conducted to characterize and perform laboratory-scale treatment of municipal drainage wastewater of Khulna, Bangladesh. Wastewater samples were collected from three different points of existing urban drain outlets into the Mayur River around Khulna. Laboratory testing shows the BOD5 and COD concentration of wastewater samples varied from 57 - 226 mg/l and 320 - 435 mg/l, respectively, and the total dissolved solids ranged from 1800 - 2525 mg/l. Therefore, a laboratory-scale treatment technology was developed to treat this wastewater. Treatment technologies adopted were primary sedimentation, followed by aeration, chemical precipitation and filtration. In treated wastewater, BOD5, COD and TDS were found to be in the range of 40 - 115 mg/l, 160 - 256 mg/l and 1356 - 1500 mg/l, respectively. These test results suggest that the performance of laboratory-scale treatment plant was not adequate to fulfil the acceptable limit (ECR’97) for safe disposal into surface water bodies. Due to poor quality of effluents, modification of laboratory-scale treatment plant was made by an activated sludge process followed by granular media filtration. The final BOD5, COD TDS and TSS concentration of effluents was found to be 1.38 - 9.8 mg/l, 32 - 192 mg/l, 590 - 1667 mg/l, and 35 - 95 mg/l respectively, which satisfy ECR’97 standard limits for safe disposal into inland water bodies.展开更多
Adsorption is a unit operation widely used for the tertiary treatment of the most diverse effluents,whose mechanism is based on removing recalcitrant compounds from the organic and inorganic origin.In this process,cho...Adsorption is a unit operation widely used for the tertiary treatment of the most diverse effluents,whose mechanism is based on removing recalcitrant compounds from the organic and inorganic origin.In this process,choosing a suitable adsorbent is a fundamental point.This review article focuses on the adsorbents with natural geological origin:minerals,clays,geopolymers,and even wastes resulted from mining activity.Therefore,over 450 articles and research papers were explored.These materials’main sources are described,and their characteristics,composition,and intrinsic properties are related to adsorption.Herein,we discuss the effects of several process parameters,such as p H,temperature,pollutant,and adsorbent concentration.Furthermore,equilibrium,kinetics,and thermodynamic aspects are also addressed,and relevant regeneration prospects and final disposal.Finally,some suggestions and perspectives on applying these adsorbents in wastewater treatment are presented as future trends.展开更多
The characteristics and harm of high concentrations of organic wastewater were introducecl firstly, and then several treatment processes and effects of high concentrations of organic wastewater were summarized, which ...The characteristics and harm of high concentrations of organic wastewater were introducecl firstly, and then several treatment processes and effects of high concentrations of organic wastewater were summarized, which can provide theoretical references for the choice of wastewater treatment process.展开更多
Information about effectiveness of a wastewater treatment plant is vital in ensuring the quality of water discharged into water bodies and the environment in general meet set standards.In this study,the performance of...Information about effectiveness of a wastewater treatment plant is vital in ensuring the quality of water discharged into water bodies and the environment in general meet set standards.In this study,the performance of a wastewater treatment plant located at the Export Processing Zone(EPZ)along River Athi in Machakos County,Kenya was assessed because the final effluent from the treatment plant is released into the river where water is used downstream.Effectiveness of the plant was assessed through the reduction percentage of pollutants between influent and effluent during the dry and wet seasons.Samples of water were collected from the following points i.e.inlet,outflow pool,outlet and along the river.The samples were analyzed for heavy metals,Total Dissolved Solids(TDS),Total Suspended Solids(TSS),Chemical Oxygen Demand(COD),Biological Oxygen Demand(BOD),organic nitrogen,phosphate,color,temperature,pH,and total coliforms.The resulting data was compared with the established standards.Standard methodologies of laboratory analysis were employed as per Kenyan regulations of 2006 on waste water treatment and discharge.From the results,the waste water treatment plant was not effective in reducing nitrates,phosphates,TDS,TSS,color,and heavy metals i.e.mercury,lead,selenium,copper and cadmium.The inefficiency was more pronounced in rain season.Nitrates(-2.04%),phosphates(-66%),mercury(-48%),lead(-48%),selenium(-2.29%)and copper(-9.75%)were high in the effluent after treatment process during the rains than in the influent.However,the treatment plant was effective in reducing Chemical Oxygen Demand(COD)and Biological Oxygen Demand(BOD).Some parameters like pH,conductivity,temperature,color and TSS were within allowable values described by Kenyan and International standards for effluent discharge into public waters.The study recommends expansion or re-designing of the treatment plant and better monitoring of the sources or types of wastewaters received at the plant for efficient and proper treatment process.Further research required on the seasonal fluctuation of pollutants along River Athi to reduce pollution of the waters.This should be coupled with studying the role of river gradient in self-cleansing of the pollutants.展开更多
The combined submerged biofilm (SBF)-activated sludge (AS) process for treatment of municipal wastewater in a small city in China is described in this paper. The process exhibited high removal efficiencies for car...The combined submerged biofilm (SBF)-activated sludge (AS) process for treatment of municipal wastewater in a small city in China is described in this paper. The process exhibited high removal efficiencies for carbonaceous substances, nitrogen and phosphorus which mainly took place in the combined SBF-AS bioreactor. The SBF-AS bioreactor was divided into pre-anoxic, anaerobic, anoxic and aerobic zones from inlet to outlet, in which fixed biofilm carriers were packed. Excellent performance had been obtained under normal operating conditions in more than one year of operation in Dong’e municipal WWTP, Shandong province, with mean removal efficiencies of BOD5 934%, COD 88%, SS 92%, NH+4-N 821%, TP 75% and TN 667%, and quite high effluent quality such as BOD5 6 to 10 mg/L, COD 20 to 40 mg/L, SS 5 to 10 mg/L, TN 10 to 20 mg/L, NH+4-N 4 to 8 mg/L and TP 06 to 10 mg/L. The effluent was reused multi-purposely, such as toilet flushing, green belt watering and artificial lake pounding. Simultaneous nitrification and denitrification took place due to the DO gradient in biofilm in aerobic zone of the SBF-AS bioreactor, which made TN removal efficiency improved remarkably in system. Some activated sludge was returned from final clarifiers to the bioreactor for phosphorus removal. The process had the advantages of low investment and low operational/maintenance (O/M) costs, low sludge yield and was preferably employed in small towns and cities.展开更多
It is particularly important to comprehensively assess the biotoxicity variation of industrial wastewater along the treatment process for ensuring the water environment security.However,intensive studies on the biotox...It is particularly important to comprehensively assess the biotoxicity variation of industrial wastewater along the treatment process for ensuring the water environment security.However,intensive studies on the biotoxicity reduction of industrial wastewater are still limited.In this study,the toxic organics removal and biotoxicity reduction of coal chemical wastewater(CCW)along a novel full-scale treatment process based on the pretreatment process-anaerobic process-biological enhanced(BE)process-anoxic/oxic(A/O)process-advanced treatment process was evaluated.This process performed great removal efficiency of COD,total phenol,NH_(4)^(+)-N and total nitrogen.And the biotoxicity variation along the treatment units was analyzed from the perspective of acute biotoxicity,genotixicity and oxidative damage.The results indicated that the effluent of pretreatment process presented relatively high acute biotoxicity to Tetrahymena thermophila.But the acute biotoxicity was significantly reduced in BE-A/O process.And the genotoxicity and oxidative damage to Tetrahymena thermophila were significantly decreased after advanced treatment.The polar organics in CCW were identified as the main biotoxicity contributors.Phenols were positively correlated with acute biotoxicity,while the nitrogenous heterocyclic compounds and polycyclic aromatic hydrocarbons were positively correlated with genotoxicity.Although the biotoxicity was effectively reduced in the novel full-scale treatment process,the effluent still performed potential biotoxicity,which need to be further explored in order to reduce environmental risk.展开更多
In order to study the feasibility of treating petro chemical wastewater by the combination of anaerobic and aerobic biological process, a research of treating wastewater in UASB reactor and aeration basin has been co...In order to study the feasibility of treating petro chemical wastewater by the combination of anaerobic and aerobic biological process, a research of treating wastewater in UASB reactor and aeration basin has been conducted. The test results shows that under moderate temperature, with 5\^2 kgCOD/(m\+3·d) volumetric load of COD Cr in the UASB reactor and 24h of HRT, 85% removal rate of BOD 5 and 83% of COD \{Cr\} and 1\^34 m\+3/(m\+3·d) volumetric gas production rate can be obtained respectively. The aerobic bio degradability can be increased by 20%—30% after the petro chemical wastewater has been treated by anaerobic process. As Ns=0\^45 kgCOD/(kgMLSS·d), HRT=4h in the aeration tank, 94% removal rate of BOD 5, 93% of COD \{Cr\}, 98\^8% total removal rate of COD \{Cr\} and 99% removal rate of BOD 5 can be reached.展开更多
Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the c...Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the control of a WWTP.In order to improve the control performance of the closed-loop system and guarantee the discharge requirements of the effluent quality,rather than take the model dependent control approaches,an active disturbance rejection control(ADRC)is utilized.Based on the control signal and system output,a phase optimized ADRC(POADRC)is designed to control the dissolved oxygen and nitrate concentration in a WWTP.The phase advantage of the phase optimized extended state observer(POESO),convergence of the POESO,and stability of the closed-loop system are analyzed from the theoretical point of view.Finally,a commonly accepted benchmark simulation model no.1.(BSM1)is utilized to test the POESO and POADRC.Linear active disturbance rejection control(LADRC)and the suggested proportion-integration(PI)control are taken to make a comparative research.Both system responses and performance index values confirm the advantage of the POADRC over the LADRC and the suggested PI control.Numerical results show that,as a result of the leading phase of the total disturbance estimation,the POESO based POADRC is an effective and promising way to control the dissolved oxygen and nitrate concentration so as to ensure the effluent quality of a WWTP.展开更多
In wastewater treatment process(WWTP), the accurate and real-time monitoring values of key variables are crucial for the operational strategies. However, most of the existing methods have difficulty in obtaining the r...In wastewater treatment process(WWTP), the accurate and real-time monitoring values of key variables are crucial for the operational strategies. However, most of the existing methods have difficulty in obtaining the real-time values of some key variables in the process. In order to handle this issue, a data-driven intelligent monitoring system, using the soft sensor technique and data distribution service, is developed to monitor the concentrations of effluent total phosphorous(TP) and ammonia nitrogen(NH_4-N). In this intelligent monitoring system, a fuzzy neural network(FNN) is applied for designing the soft sensor model, and a principal component analysis(PCA) method is used to select the input variables of the soft sensor model. Moreover, data transfer software is exploited to insert the soft sensor technique to the supervisory control and data acquisition(SCADA) system. Finally, this proposed intelligent monitoring system is tested in several real plants to demonstrate the reliability and effectiveness of the monitoring performance.展开更多
文摘In this research, the quality of the wastewater discharged into the environment has been investigated. The effluent from solar desalination pond contains large amounts of TDS (3.68 grams per liter) and TH (6.50 grams per liter). Since the use of filter is not economical in this case, three types of commercial coagulants such as aluminum sulfate, ferric chloride and ferric sulfide have been used in this study. The main parameters such as effectiveness of three inorganic coagulants, ammonium sulfate, ferric sulfate, and ferric chloride, which separately help to remove hardness, have been studied. According to the results, using laboratory test, 25/g of ferric sulfate as coagulant is best coagulant mass and the ratio of 4 to 3 for auxiliary coagulant (sodium carbonate and sodium hydroxide) to coagulant will be best ratio. Also, the mixing rate of 120 rpm in the first reactor will give the best mixing speed. These conditions will lead to 0.348 grams per liter of TDS, 0.345 grams per liter of TH and 0.195 grams per liter of calcium hardness and 300 micro Siemens electrical conductivity of the purified sample.
文摘Anaerobic treatment model treats fish processing wastewater to be necessary for a small and medium factory that is very popular in Vietnam and other countries.Several techniques have been proposed.However,they are quite expensive and hard to operate,especially in remote areas.In this study,the hydraulic retention times(HRT)including 3,5,and 7 hours with a various organic loading rate of 1.5 to 6.5 kg COD/m3/day were investigated.Biomass concentration as mix-liquor volatile suspended solid(MLVSS)in the model is at 6,000 to 9,000 mg/L.On the basis of the result the optimal HRT with a 4.0 kg COD/m3/day organic loading rate was 8 hours which BOD5,COD removal efficiency were 92.18,87.36 percent respectively.By the end of the optimal hydraulic retention times,the total methane gas volume as a by-product was collected with 2.6 liters.
基金Project supported by the Hi-Tech Research and Development Program(863)of China(No. 2002AA601310).
文摘Chinese traditional medicine wastewater, rich in macromolecule and easy to foam in aerobic biodegradation such as Glycosides, was treated by two identical bench-scale aerobic submerged membrane bioreactors (SMBRs) operated in parallel under the same feed, equipped with the same electronic control backwashing device. One was used as the control SMBR (CSMBR) while the other was dosed with powdered activated carbon (PAC) (PAC-amended SMBR, PSMBR). The backwashing interval was 5 min. One suction period was about 90 min by adjusting preestablished backwashing vacuum and pump frequency. The average flux of CSMBR during a steady periodic state of 24 d (576 h) was 5.87 L/h with average hydraulic residence time (HRT) of 5.97 h and that of PSMBR during a steady periodic state of 30 d (720 h) was 5.85 L/h with average HRT of 5.99 h. The average total chemical oxygen demand (COD) removal efficiency of CSMBR was 89.29% with average organic loading rate (OLR) at 4.16 kg COD/(m^3.d) while that of PSMBR was 89.79% with average OLR at 5.50 kg COD/(m^3.d). COD concentration in the effluent of both SMBRs achieved the second level of the general wastewater effluent standard GB8978-1996 for the raw medicine material industry (300 mg/L). Hence, SMBR with electronic control backwashing was a viable process for medium-strength Chinese traditional medicine wastewater treatment. Moreover, the increasing rates of preestablished backwashing vacuum, pump frequency, and vacuum and flux loss caused by mixed liquor in PSMBR all lagged compared to those in CSMBR; thus the actual operating time of the PSMBR system without membrane cleaning was extended by up to 1.25 times in contrast with the CSMBR system, and the average total COD removal efficiency of PSMBR was enhanced with higher average OLR.
文摘The advanced treatment using integrated Fenton's reaction and coagulation process was investigated in this study. Before the advancement, the pharmaceutical wastewater containing lincomycin hydrochloride was pretreated by UASB (upflow anaerobic sludge bed) and a SBR (sequencing batch reactor) process. The residual recalcitrant compounds, measured by gas chromatographymass spectrometry (GC-MS), mainly consisted of alcohols, phenols, and nitrogenous and sulfur compounds. The experimental results indicated that when the Fenton's reaction was conducted at pH=3.0, H2O2CODOcr=0.27, H2O2/Fe^2+=3:1 and 30 min of reaction time, and the coagulation process operated at a sulfate aluminum concentration of 800 mg/L and pH value of 5.0, the color and COD in the wastewater decreased by 94% and 73%, respectively; with a finale COD concentration of 267 mg/L and color level of 40 units, meeting the secondary standard of GB8978-1996 for industrial wastewater.
基金Supported by the Scientific Research Foundation for Postgraduates of ZhengZhou University (A1003) Open Foundation of Provincial Key Laboratory of Environmental Material and Environmental Engineering (K11027)
文摘[ Objective ] The study aimed at treating wastewater treatment plant (WWTP) effluent by using bio-film reactor with filamentous bamboo as bio-carrier. [ Method] With the aid of a continuous flow reactor, a bio-film reactor using filamentous bamboo as bio-carrier was used to treat WWTP effluent with low C/N ratio, and the removal effects of CODc,, TN (total nitrogen), and NO3--N in the wastewater were analyzed.[ Result ] The average removal rates of CODcr, TN, and NO3- -N reached 47.7%, 23.6% and 34.5% when the C/N ratio of influent was around 2. In addi- tion, a stable bio-film was formed very well in the secondary effluent with low C/N ratio and hardly degradable organic pollutants. The pollutants could be removed effectively because of the excellent surface characteristics and compositions of filamentous bamboo. [ Conclusion] The research provides a new method to treat WWTP effluent with low C/N ratio.
基金supported by the Key Project of Environmental Science and Technology of Shandong Province(Grant No.2006003-2)
文摘Based on the experiments of utilization of garlic processing wastewater in a lotus pond, this study demonstrates that lotus pond wetlands have a remarkable ability to remove organic pollutants and decrease chemical oxygen demand (CODCr), biochemical oxygen demand (BOD5), and suspended substances (SS) in garlic processing wastewater. Results also show evident effects of lotus roots on absorption of NH3-N. The pH value in a lotus pond with wastewater discharged was relatively stable. The water quality in the lotus pond reached the class Ⅱ emission standard, according to the Integrated Wastewater Discharge Standard (GB8978-1996), seven days after pretreated garlic processing wastewater had been discharged into the lotus pond. Garlic processing wastewater irrigation does not produce pollution in the pond sediment and has no negative effect on the growth of lotus roots. Due to utilization of garlic processing wastewater, the output of lotus roots increased by 3.0% to 8.3%, and the quality of lotus roots was improved. Therefore, better purification and utilization results can be achieved.
基金This work was supported by the Heilongjiang Natural Science Foundation(No.E2007-04)the National Natural Science Foundation of China(No.50908062)the State Key Laboratory of Urban Water Resource and Environment(No.HIT-QAK200808).
文摘A laboratory scale test was conducted in a combined membrane process (CMP) with a capacity of 2.91 m3/d for 240 d to treat the mixed wastewater of humidity condensate, hygiene wastewater and urine in submarine cabin during prolonged voyage. Removal performance of chemical oxygen demand (COD), ammonia nitrogen (NH4^+-N), turbidity and anionic surfactants (LAS) was investigated under different conditions. It was observed that the effluent COD, NH4^+-N, turbidity and LAS flocculated in ranges of 0.19-0.85 mg/L, 0.03-0.18 mg/L, 0.0-0.15 NTU and 0.0-0.05 mg/L, respectively in spite of considerable fluctuation in corresponding influent of 2120-5350 mg/L, 79.5-129.3 mg/L, 110-181.1NTU and 4.9-5.4 mg/L. The effluent quality of the CMP could meet the requirements of mechanical water and hygiene water according to the class I water quality standards in China (GB3838-2002). The removal rates of COD, NH4^+-N, turbidity and LAS removed in the MBR were more than 90%, which indicated that biodegradation is indispensable and plays a major role in the wastewater treatment and reuse. A model, built on the back propagation neural network (BPNN) theory, was developed for the simulation of CMP and produced high reliability. The average error of COD and NH4^+-N was 5.14% and 6.20%, respectively, and the root mean squared error of turbidity and LAS was 2.76% and 1.41%, respectively. The results indicated that the model well fitted the laboratory data, and was able to simulate the removal of COD, NH4^+-N, turbidity and LAS. It also suggested that the model proposed could reflect and manage the operation of CMP for the treatment of the mixed wastewaters in submarine.
基金supported by the National Natural Science Foundation of China(No.51338005)
文摘The presence of sulfonamide antibiotics in aquatic environments has received increasing attention in recent years.Sulfadiazine(SD),a widely used heterocyclic sulfonamide pharmaceutical,has entered into the receiving water body.In this paper,gamma rays are used to irradiate samples of sulfadiazine antibiotics-containing wastewater.The results demonstrate that SD can be effectively degraded by irradiation,but the mineralization degree of SD(in terms of TOC) is not as efficient as the SD degradation.The addition of Fe^(2+) can significantly enhance the SD degradation and mineralization through the generation of hydroxyl radical by catalytic decomposition of H_2O_2 from water radiolysis.Ion chromatography analysis indicates that sulfate ions(SO_4^(2-)) and formate(HCOO^-) are the main intermediate products.Gamma irradiation is a promising technology for removing low-concentration antibiotics from water and wastewater.
文摘A flexible fibre biofilm reactor was developed for treatment of organic wastewaters.The hydrodynamic characteristics and mass transfer coefficients of oxygen were studied and compared with those of the conventional activated sludge processes.Tracer experiments were performed to obtain the residence time distributions of the reactors.The results indicated that both reactors could be treated as mixed flow reactors.The effects of flow rates of water and air on the overall mass transfer coefficient of oxygen were investigated,and the correlations between the mass transfer coefficient and the ratio of flow rates were obtained.Compared to the conventional activated sludge reactor,the mass transfer coefficients in the flexible fibre reactor were similar to but slightly lower,and less sensitive to the variation in the ratio of flow rates.It indicated that the fibre packing in the reactor hindered the oxygen transfer to some extent.
文摘The study was conducted to characterize and perform laboratory-scale treatment of municipal drainage wastewater of Khulna, Bangladesh. Wastewater samples were collected from three different points of existing urban drain outlets into the Mayur River around Khulna. Laboratory testing shows the BOD5 and COD concentration of wastewater samples varied from 57 - 226 mg/l and 320 - 435 mg/l, respectively, and the total dissolved solids ranged from 1800 - 2525 mg/l. Therefore, a laboratory-scale treatment technology was developed to treat this wastewater. Treatment technologies adopted were primary sedimentation, followed by aeration, chemical precipitation and filtration. In treated wastewater, BOD5, COD and TDS were found to be in the range of 40 - 115 mg/l, 160 - 256 mg/l and 1356 - 1500 mg/l, respectively. These test results suggest that the performance of laboratory-scale treatment plant was not adequate to fulfil the acceptable limit (ECR’97) for safe disposal into surface water bodies. Due to poor quality of effluents, modification of laboratory-scale treatment plant was made by an activated sludge process followed by granular media filtration. The final BOD5, COD TDS and TSS concentration of effluents was found to be 1.38 - 9.8 mg/l, 32 - 192 mg/l, 590 - 1667 mg/l, and 35 - 95 mg/l respectively, which satisfy ECR’97 standard limits for safe disposal into inland water bodies.
基金the funding agencies CAPES,CNPq,and FAPERGS for financial support。
文摘Adsorption is a unit operation widely used for the tertiary treatment of the most diverse effluents,whose mechanism is based on removing recalcitrant compounds from the organic and inorganic origin.In this process,choosing a suitable adsorbent is a fundamental point.This review article focuses on the adsorbents with natural geological origin:minerals,clays,geopolymers,and even wastes resulted from mining activity.Therefore,over 450 articles and research papers were explored.These materials’main sources are described,and their characteristics,composition,and intrinsic properties are related to adsorption.Herein,we discuss the effects of several process parameters,such as p H,temperature,pollutant,and adsorbent concentration.Furthermore,equilibrium,kinetics,and thermodynamic aspects are also addressed,and relevant regeneration prospects and final disposal.Finally,some suggestions and perspectives on applying these adsorbents in wastewater treatment are presented as future trends.
文摘The characteristics and harm of high concentrations of organic wastewater were introducecl firstly, and then several treatment processes and effects of high concentrations of organic wastewater were summarized, which can provide theoretical references for the choice of wastewater treatment process.
文摘Information about effectiveness of a wastewater treatment plant is vital in ensuring the quality of water discharged into water bodies and the environment in general meet set standards.In this study,the performance of a wastewater treatment plant located at the Export Processing Zone(EPZ)along River Athi in Machakos County,Kenya was assessed because the final effluent from the treatment plant is released into the river where water is used downstream.Effectiveness of the plant was assessed through the reduction percentage of pollutants between influent and effluent during the dry and wet seasons.Samples of water were collected from the following points i.e.inlet,outflow pool,outlet and along the river.The samples were analyzed for heavy metals,Total Dissolved Solids(TDS),Total Suspended Solids(TSS),Chemical Oxygen Demand(COD),Biological Oxygen Demand(BOD),organic nitrogen,phosphate,color,temperature,pH,and total coliforms.The resulting data was compared with the established standards.Standard methodologies of laboratory analysis were employed as per Kenyan regulations of 2006 on waste water treatment and discharge.From the results,the waste water treatment plant was not effective in reducing nitrates,phosphates,TDS,TSS,color,and heavy metals i.e.mercury,lead,selenium,copper and cadmium.The inefficiency was more pronounced in rain season.Nitrates(-2.04%),phosphates(-66%),mercury(-48%),lead(-48%),selenium(-2.29%)and copper(-9.75%)were high in the effluent after treatment process during the rains than in the influent.However,the treatment plant was effective in reducing Chemical Oxygen Demand(COD)and Biological Oxygen Demand(BOD).Some parameters like pH,conductivity,temperature,color and TSS were within allowable values described by Kenyan and International standards for effluent discharge into public waters.The study recommends expansion or re-designing of the treatment plant and better monitoring of the sources or types of wastewaters received at the plant for efficient and proper treatment process.Further research required on the seasonal fluctuation of pollutants along River Athi to reduce pollution of the waters.This should be coupled with studying the role of river gradient in self-cleansing of the pollutants.
文摘The combined submerged biofilm (SBF)-activated sludge (AS) process for treatment of municipal wastewater in a small city in China is described in this paper. The process exhibited high removal efficiencies for carbonaceous substances, nitrogen and phosphorus which mainly took place in the combined SBF-AS bioreactor. The SBF-AS bioreactor was divided into pre-anoxic, anaerobic, anoxic and aerobic zones from inlet to outlet, in which fixed biofilm carriers were packed. Excellent performance had been obtained under normal operating conditions in more than one year of operation in Dong’e municipal WWTP, Shandong province, with mean removal efficiencies of BOD5 934%, COD 88%, SS 92%, NH+4-N 821%, TP 75% and TN 667%, and quite high effluent quality such as BOD5 6 to 10 mg/L, COD 20 to 40 mg/L, SS 5 to 10 mg/L, TN 10 to 20 mg/L, NH+4-N 4 to 8 mg/L and TP 06 to 10 mg/L. The effluent was reused multi-purposely, such as toilet flushing, green belt watering and artificial lake pounding. Simultaneous nitrification and denitrification took place due to the DO gradient in biofilm in aerobic zone of the SBF-AS bioreactor, which made TN removal efficiency improved remarkably in system. Some activated sludge was returned from final clarifiers to the bioreactor for phosphorus removal. The process had the advantages of low investment and low operational/maintenance (O/M) costs, low sludge yield and was preferably employed in small towns and cities.
基金supported by the Natural Science Foundation of Shandong Province,China(No.ZR2021QE227)the Natural Science Foundation of Shandong Province,China(No.ZR2021QE272)+1 种基金the Open Project of State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(No.ES202120)the Taishan Scholars Program of Shandong Province,China(No.tsqn201812091)。
文摘It is particularly important to comprehensively assess the biotoxicity variation of industrial wastewater along the treatment process for ensuring the water environment security.However,intensive studies on the biotoxicity reduction of industrial wastewater are still limited.In this study,the toxic organics removal and biotoxicity reduction of coal chemical wastewater(CCW)along a novel full-scale treatment process based on the pretreatment process-anaerobic process-biological enhanced(BE)process-anoxic/oxic(A/O)process-advanced treatment process was evaluated.This process performed great removal efficiency of COD,total phenol,NH_(4)^(+)-N and total nitrogen.And the biotoxicity variation along the treatment units was analyzed from the perspective of acute biotoxicity,genotixicity and oxidative damage.The results indicated that the effluent of pretreatment process presented relatively high acute biotoxicity to Tetrahymena thermophila.But the acute biotoxicity was significantly reduced in BE-A/O process.And the genotoxicity and oxidative damage to Tetrahymena thermophila were significantly decreased after advanced treatment.The polar organics in CCW were identified as the main biotoxicity contributors.Phenols were positively correlated with acute biotoxicity,while the nitrogenous heterocyclic compounds and polycyclic aromatic hydrocarbons were positively correlated with genotoxicity.Although the biotoxicity was effectively reduced in the novel full-scale treatment process,the effluent still performed potential biotoxicity,which need to be further explored in order to reduce environmental risk.
文摘In order to study the feasibility of treating petro chemical wastewater by the combination of anaerobic and aerobic biological process, a research of treating wastewater in UASB reactor and aeration basin has been conducted. The test results shows that under moderate temperature, with 5\^2 kgCOD/(m\+3·d) volumetric load of COD Cr in the UASB reactor and 24h of HRT, 85% removal rate of BOD 5 and 83% of COD \{Cr\} and 1\^34 m\+3/(m\+3·d) volumetric gas production rate can be obtained respectively. The aerobic bio degradability can be increased by 20%—30% after the petro chemical wastewater has been treated by anaerobic process. As Ns=0\^45 kgCOD/(kgMLSS·d), HRT=4h in the aeration tank, 94% removal rate of BOD 5, 93% of COD \{Cr\}, 98\^8% total removal rate of COD \{Cr\} and 99% removal rate of BOD 5 can be reached.
基金supported by the Key program of Beijing Municipal Education Commission(KZ201810011012)National Natural Science Foundation of China(61873005)Support Project of High-level Teachers in Beijing Municipal Universities in the Period of 13th Fiveyear Plan(CIT&TCD201704044)。
文摘Waste water treatment process(WWTP)control has been attracting more and more attention.However,various undesired factors,such as disturbance,uncertainties,and strong nonlinear couplings,propose big challenges to the control of a WWTP.In order to improve the control performance of the closed-loop system and guarantee the discharge requirements of the effluent quality,rather than take the model dependent control approaches,an active disturbance rejection control(ADRC)is utilized.Based on the control signal and system output,a phase optimized ADRC(POADRC)is designed to control the dissolved oxygen and nitrate concentration in a WWTP.The phase advantage of the phase optimized extended state observer(POESO),convergence of the POESO,and stability of the closed-loop system are analyzed from the theoretical point of view.Finally,a commonly accepted benchmark simulation model no.1.(BSM1)is utilized to test the POESO and POADRC.Linear active disturbance rejection control(LADRC)and the suggested proportion-integration(PI)control are taken to make a comparative research.Both system responses and performance index values confirm the advantage of the POADRC over the LADRC and the suggested PI control.Numerical results show that,as a result of the leading phase of the total disturbance estimation,the POESO based POADRC is an effective and promising way to control the dissolved oxygen and nitrate concentration so as to ensure the effluent quality of a WWTP.
基金Supported by the National Natural Science Foundation of China(61622301,61533002)Beijing Natural Science Foundation(4172005)Major National Science and Technology Project(2017ZX07104)
文摘In wastewater treatment process(WWTP), the accurate and real-time monitoring values of key variables are crucial for the operational strategies. However, most of the existing methods have difficulty in obtaining the real-time values of some key variables in the process. In order to handle this issue, a data-driven intelligent monitoring system, using the soft sensor technique and data distribution service, is developed to monitor the concentrations of effluent total phosphorous(TP) and ammonia nitrogen(NH_4-N). In this intelligent monitoring system, a fuzzy neural network(FNN) is applied for designing the soft sensor model, and a principal component analysis(PCA) method is used to select the input variables of the soft sensor model. Moreover, data transfer software is exploited to insert the soft sensor technique to the supervisory control and data acquisition(SCADA) system. Finally, this proposed intelligent monitoring system is tested in several real plants to demonstrate the reliability and effectiveness of the monitoring performance.