scholarly journals Synthesis of Atmospherically Stable Zero-Valent Iron Nanoparticles (nZVI) for the Efficient Catalytic Treatment of High-Strength Domestic Wastewater

Catalysts ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 26
Author(s):  
Afzal Ansari ◽  
Vasi Uddin Siddiqui ◽  
Md. Khursheed Akram ◽  
Weqar Ahmad Siddiqi ◽  
Anish Khan ◽  
...  
Keyword(s):  
Positive Impact ◽  
Oxygen Demand ◽  
Visible Spectrum ◽  
Aerobic Condition ◽  
Domestic Wastewater ◽  
Operating Conditions ◽  
Bandgap Energy ◽  
Ambient Conditions ◽  
High Concentration ◽  
Catalytic Treatment

Here, we report the fabrication of nZVI by the wet chemical technique in the presence of ethanol using ferric iron and sodium borohydride as the reducing agents under ambient conditions. The obtained nZVI particles are mainly in a zero-valent oxidation state and do not undergo significant oxidation for several weeks. The structural and morphological parameters of nZVI were investigated by using UV, XRD, SEM, EDX, TEM, and DLS analysis. The optical nature, bandgap energy, and absorption edge were all revealed by the UV–visible spectrum. The phase development and crystallinity of nZVI particles were shown by the XRD pattern. The morphological investigation revealed that the nanoparticles were spherical with an average size of 34–110 nm by using ImageJ software, and the elemental analysis was analyzed using EDX. Furthermore, the catalytic treatment performance of domestic wastewater was evaluated in terms of pH, COD (chemical oxygen demand) solubilization, total solids (TS), volatile solids (VS), phosphorous, and total nitrogen (TN) reduction under aerobic and anaerobic operating conditions. The effluent was subjected to a process evaluation with a different range (100–500 mg/L) of nZVI dosages. The COD solubilization and suspended solids reduction were significantly improved in the anaerobic condition in comparison to the aerobic condition. Furthermore, the effect of nZVI on phosphorous (PO43−) reduction was enhanced by the electrons of iron ions. The high concentration of nZVI dosing has a positive impact on COD solubilization and phosphorous removal regardless of the aeration condition with 400 mg/L of nZVI dosage.

Treatment of Refinery Wastewater with Isolated Biological Aerated Filters: A Pilot-Scale Study

2012 ◽  
Vol 610-613 ◽  
pp. 2332-2341
Author(s):  
Jian Guang Huang ◽  
Li Zhong ◽  
Wen Yu Xie
Keyword(s):  
Waste Water ◽  
Waste Water Treatment ◽  
Oxygen Demand ◽  
Volume Ratio ◽  
Pilot Scale ◽  
Mean Value ◽  
Operating Conditions ◽  
Water Volume ◽  
High Concentration ◽  
Set Up

A pilot scale biochemical treatment system containing three isolated biological aerated filters, one oil-separation pool and one secondary sedimentation tank was set up and used for high concentration organic waste water treatment. Effect of different operating conditions on Chemical Oxygen Demand (CODCr), sulphides, hydroxybenzene and oil degradation was investigated. And the ways of sulphides removal were also explored. While CODCr, the concentrations of sulphides, hydroxybenzene and oil in the waste water are no more than 1500 mg/L, 800 mg/L, 15 mg/L and 150mg/L, respectively, the system can run stably and the total removal of these pollutants is 88.8%, 98.8%, 96.8% and 91.0% accordingly though hydraulic retention time (HRT) varies from 7.95 hr to 15.90 hr and the air/water volume ratio (AWVR) varies from 12 to 8. Most of the sulphides are removed by Biodegradation with Isolated Biological Aerated Filters. Most of the pollutants are removed in the 1st BAF and about 96.5% by mean value of sulphides transforme into elemental sulfur and only about 2.7% by mean value of sulphides transforme into sulphates.

Removal of Suspended Solids, Chemical Oxygen Demand and Color from Domestic Wastewater Using Sago Starch as Coagulant

2015 ◽  
Vol 802 ◽  
pp. 519-524
Author(s):  
Wan Izatul Saadiah Wan Kamar ◽  
Hamidi Abdul Aziz ◽  
Siti Fatihah Ramli
Keyword(s):  
Chemical Oxygen Demand ◽  
Suspended Solids ◽  
Sewage Treatment Plant ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Operating Conditions ◽  
Wastewater Sample ◽  
Sago Starch ◽  
Rapid Mixing ◽  
Slow Mixing

Sago starch has been widely used in industrial fields, especially in food, non-food, and animal feed biotechnology. Malaysia is one of the highest local sources of sago starch. The alternative use of sago starch as a coagulant for domestic wastewater treatment was investigated in this study. The wastewater sample was collected from the Juru Regional Sewage Treatment Plant in Juru, Penang. The studied parameters include the chemical oxygen demand (COD), suspended solids, and color. Standard jar test procedures were conducted. The initial operating conditions were 200 rpm for 3 min of rapid mixing, 40 rpm for 30 min of slow mixing, and 30 min of settling. The optimum conditions included a pH of 7 and dosage of 2000 mg/L, with rapid mixing at 100 rpm for 1 min, slow mixing at 20 rpm for 30 min, and 18 min of settling. The removal rate of COD and color at these conditions was 70%. Simultaneously, 82% of SS was also removed. The results indicated that sago starch has good potential to treat domestic wastewater; the coagulant may also efficiently treat other types of wastewater.

Optimal performance of an immersed membrane bioreactor equipped with a draft tube for domestic wastewater reclamation

2006 ◽  
Vol 54 (10) ◽  
pp. 155-162 ◽  
Author(s):  
F. Yang ◽  
A. Bick ◽  
S. Shandalov ◽  
G. Oron
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Domestic Wastewater ◽  
Operating Conditions ◽  
Hydrodynamic Conditions ◽  
Wastewater Reclamation ◽  
Ambient Conditions ◽  
Optimal Operating

One of the options to prevent membrane fouling is to implement air lifting that can improve the cake removal from the membrane surface. This study presents the results of tests that were carried out at the Institutes for Desert Research, Kiryat Sde-Boker, Israel, and focused on the influence of hydrodynamic conditions on fouling in a pilot-scale immersed membrane bioreactor (IMBR) using a hollow fiber membrane module of ZW-10 (Zenon Environmental, Canada) under ambient conditions. In this system, the cross-flow velocities across the membrane surface were induced by one conical and four cylindrical draft-tubes. The relationship between the crossflow velocity and the aeration intensity, the influence of the crossflow on fouling rate under various hydrodynamic conditions were investigated and optimal operating conditions were obtained. Optimal operating conditions were reached during the long-term experiment period (70 days) for the treatment of domestic wastewater. The system was stable without external chemical cleaning. The results showed that the permeate was of high quality, and the removal of COD and BOD was 94.0% and 98.8%, respectively.The crossflow near the membrane surface reveals a major contribution for minimizing membrane fouling, and could offer guidelines for future design of similar systems.

scholarly journals Determination on inhibition effects of coagulants used in wastewater treatment plants on anaerobic digester

2020 ◽  
Vol 82 (9) ◽  
pp. 1877-1884
Author(s):  
Güler Türkoğlu Demirkol ◽  
Gökhan Balcıoğlu ◽  
Nurtaç Öz ◽  
Moiz Elnekave ◽  
Bülent Armağan ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Suspended Solids ◽  
Wastewater Treatment Plants ◽  
Settling Tank ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
High Concentration ◽  
Biological Methods ◽  
Solids Removal

Abstract Domestic wastewaters causing pollution contain inorganic and/or organic materials. When the domestic wastewater outflows to the receiving waters, it causes physical, chemical, and biological pollution in them, and deteriorates the ecological balance of those waters. In the treatment of wastewater, various treatment methods are available depending on the pollution strength of the wastewater. Besides mechanical and biological methods, wastewater treatment with physicochemical methods is still one of the most effective and economical options. Particularly in wastewater with a high concentration of suspended solids, this method is very successful, and obtaining high suspended solids removal efficiencies is very possible. In this study, the effects of the use of coagulant and coagulant aid to be used in a treatment plant where domestic wastewater treatment is carried out are determined to increase the treatment efficiency of a biological treatment that comes later in the stages of the treatment. The effluent of the pre-settling tank may contain a lot of suspended solids. This presence of excess suspended solids decreases the efficiency at other levels of treatment and causes energy loss. In the experiments, the standard jar and inhibition tests are done as a method. As a result of the conducted studies, it is determined that the FeCl3, Synthetic coagulant LP 526, FeClSO4, and the combination of anionic polyelectrolyte yield the best results in the removal of the parameters of chemical oxygen demand (COD), total suspended solids (TSS), and volatile suspended solids (VSS). While FeCl3, APE 65, APE 85, Synthetic coagulant LP 526, and FeClSO4 did not show any inhibition effect in the sludge, APE 67, CPE 84, and (Al2(SO4)3 are found to cause inhibition in the sludge.

The effect of aeration and effluent recycling on domestic wastewater treatment in a pilot-plant system of duckweed ponds

2013 ◽  
Vol 69 (2) ◽  
pp. 350-357 ◽  
Author(s):  
Miriam Ben-shalom ◽  
Semion Shandalov ◽  
Asher Brenner ◽  
Gideon Oron
Keyword(s):  
Wastewater Treatment ◽  
Positive Impact ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Pollutant Removal ◽  
Domestic Wastewater Treatment ◽  
In Series ◽  
Removal Efficiencies ◽  
Effluent Recycling

Three pilot-scale duckweed pond (DP) wastewater treatment systems were designed and operated to examine the effect of aeration and effluent recycling on treatment efficiency. Each system consisted of two DPs in series fed by pre-settled domestic sewage. The first system (duckweed+ conventional treatment) was ‘natural’ and included only duckweed plants. The second system (duckweed aeration) included aeration in the second pond. The third system (duckweed+ aeration+ circulation) included aeration in the second pond and effluent recycling from the second to the first pond. All three systems demonstrated similarly efficient removal of organic matter and nutrients. Supplemental aeration had no effect on either dissolved oxygen levels or on pollutant removal efficiencies. Although recycling had almost no influence on nutrient removal efficiencies, it had a positive impact on chemical oxygen demand and total suspended solids removals due to equalization of load and pH, which suppressed algae growth. Recycling also improved the appearance and growth rate of the duckweed plants, especially during heavy wastewater loads.

scholarly journals Recycling of rural abandoned constructed wetlands: mariculture wastewater treatment

2021 ◽  
Author(s):  
Yu Xin ◽  
Lin Liu ◽  
Lili Wei ◽  
Xu Huang ◽  
Chaoxiang Liu
Keyword(s):  
Bacterial Community ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Ammonium Nitrogen ◽  
Operating Conditions ◽  
Maximum Adsorption Capacity ◽  
Marine Aquaculture ◽  
Significant Difference ◽  
The Family ◽  
Dominant Bacteria

Abstract This study aimed to investigate the behavioral shifts of constructed wetland (CW) when the treated water was changed from domestic wastewater to mariculture wastewater. The results showed that the average removal efficiencies of ammonium nitrogen (), total nitrogen and chemical oxygen demand (COD) were 29.54, 46.07 and 57.15% in mariculture wastewater, respectively, which were significantly lower than those in domestic wastewater (71.35, 66.34 and 74.98%, respectively). While there was no significant difference in the removal efficiency of nitrate and phosphate (P > 0.05) between the two systems. Based on the analysis of bacterial community and adsorption properties, the results further indicated that the removal mechanism of between both systems was mainly due to substrate adsorption: the maximum adsorption capacity of on the substrate in mariculture wastewater was 5,432 mg kg−1, whereas that in domestic wastewater was 18,033 mg kg−1. In terms of bacterial communities, the dominant bacteria at the family level were Victivallaceae (18.63%) in domestic wastewater and Porphyromonadaceae (18.37%) in mariculture wastewater, which showed the significant alteration to the bacterial community. In conclusion, this study showed that conventional CW could be used for treating wastewater from land-based marine aquaculture, while the operating conditions needed to be optimized in the process of application.

A performance evaluation of three membrane bioreactor systems: aerobic, anaerobic, and attached-growth

2011 ◽  
Vol 63 (12) ◽  
pp. 2999-3005 ◽  
Author(s):  
A. Achilli ◽  
E. A. Marchand ◽  
A. E. Childress
Keyword(s):  
Membrane Fouling ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Developed Countries ◽  
Operating Conditions ◽  
Growth Media ◽  
Positive Role ◽  
Critical Flux ◽  
Attached Growth ◽  
Human Needs

Water sustainability is essential for meeting human needs for drinking water and sanitation in both developing and developed countries. Reuse, decentralization, and low energy consumption are key objectives to achieve sustainability in wastewater treatment. Consideration of these objectives has led to the development of new and tailored technologies in order to balance societal needs with the protection of natural systems. Membrane bioreactors (MBRs) are one such technology. In this investigation, a comparison of MBR performance is presented. Laboratory-scale submerged aerobic MBR (AMBR), anaerobic MBR (AnMBR), and attached-growth aerobic MBR (AtMBR) systems were evaluated for treating domestic wastewater under the same operating conditions. Long-term chemical oxygen demand (COD) and total organic carbon (TOC) monitoring showed greater than 80% removal in the three systems. The AnMBR system required three months of acclimation prior to steady operation, compared to one month for the aerobic systems. The AnMBR system exhibited a constant mixed liquor suspended solids concentration at an infinite solids retention time (i.e. no solids wasting), while the aerobic MBR systems produced ∼0.25 g of biomass per gram of COD removed. This suggests a more economical solids management associated with the AnMBR system. Critical flux experiments were performed to evaluate fouling potential of the MBR systems. Results showed similar critical flux values between the AMBR and the AnMBR systems, while the AtMBR system showed relatively higher critical flux value. This result suggests a positive role of the attached-growth media in controlling membrane fouling in MBR systems.

scholarly journals Multivariate Chemometric Analysis of Membrane Fouling Patterns in Biofilm Ceramic Membrane Bioreactor

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 982 ◽  
Author(s):  
Olga Kulesha ◽  
Zakhar Maletskyi ◽  
Harsha Ratnaweera
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Operating Conditions ◽  
Volume Index ◽  
Least Squares Regression ◽  
Effective Lifetime ◽  
Term Operation

Membrane fouling highly limits the development of Membrane bioreactor technology (MBR), which is among the key solutions to water scarcity. The current study deals with the determination of the fouling propensity of filtered biomass in a pilot-scale biofilm membrane bioreactor to enable the prediction of fouling intensity. The system was designed to treat domestic wastewater with the application of ceramic microfiltration membranes. Partial least squares regression analysis of the data obtained during the long-term operation of the biofilm-MBR (BF-MBR) system demonstrated that Mixed liquor suspended solids (MLSS), diluted sludge volume index (DSVI), chemical oxygen demand (COD), and their slopes are the most significant for the estimation and prediction of fouling intensity, while normalized permeability and its slope were found to be the most reliable fouling indicators. Three models were derived depending on the applied operating conditions, which enabled an accurate prediction of the fouling intensities in the system. The results will help to prevent severe membrane fouling via the change of operating conditions to prolong the effective lifetime of the membrane modules and to save energy and resources for the maintenance of the system.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

scholarly journals Treatment of fish processing industry wastewater using hydrodynamic cavitational reactor with biodegradability improvement

2019 ◽  
Vol 80 (12) ◽  
pp. 2310-2319 ◽  
Author(s):  
Prashant Dhanke ◽  
Sameer Wagh ◽  
Abhijeet Patil
Keyword(s):  
Organic Matter ◽  
New Technology ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Hydrodynamic Cavitation ◽  
Inlet Pressure ◽  
Fish Processing ◽  
Processing Industry ◽  
Cavitation Effect ◽  
Processing Plants

Abstract Water generated from the fish processing industry is contaminated with organic matter. This organic matter present in wastewater increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD). A new technology, hydrodynamic cavitation (HC) is used to deal with this wastewater produced in fish processing plants. The orifice plate is used in the HC reactor to generate a cavitation effect. The intensification of this technique was carried out with the help of hydrogen peroxide (H2O2) and TiO2. The treatment of this wastewater is reported in terms of percent degradation in BOD and COD and in biodegradability index (BI). Operating parameters like inlet pressure, pH, operating temperature and H2O2 doses were used to find the optimum condition. 15 g/L of H2O2 gave 69.5% reduction of COD in the 120 min of treatment that also increases BI value to 0.93 at inlet pressure 8 bar, Plate-5, temperature (30 °C), and pH 4. In the ultrasonic cavitation (UC) reactor, COD reduction is 68.7% without TiO2 and with TiO2 it is 71.2%. Also, this HC and UC reactor reduced CFU count to a great extent at the same operating conditions.

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