scholarly journals A study of the treatment of high-salt chromium-containing wastewater by the photocatalysis-constructed wetland combination method

2019 ◽  
Vol 80 (10) ◽  
pp. 1956-1966 ◽  
Author(s):  
Dandan Li ◽  
Fengzhen Chen ◽  
Jianqiu Han
Keyword(s):  
Constructed Wetland ◽  
Treatment Time ◽  
Reduction Rate ◽  
Oxygen Demand ◽  
High Salt ◽  
Combination Method ◽  
Treated Wastewater ◽  
System A ◽  
Combination System

Abstract In this study, iron ore slag as the photocatalyst was introduced into a constructed wetland simulation system. A comparative experiment of the constructed wetland method and photocatalysis-constructed wetland combination method that treats the high-salt chromium-containing wastewater was carried out. The best hydraulic retention time (HRT) of the photocatalysis-constructed wetland combination system was studied. The effects of these two methods on biochemical oxygen demand (BOD5), chemical oxygen demand (COD) removal and Cr(VI) reduction rate of the high-salt chromium-containing wastewater were analysed after 14 periods. The results showed that under the optimal HRT of 4 hours, the COD and BOD5 of the wastewater reduced by 47% and 31%, and the reduction rate of Cr(VI) was 83% separately in the constructed wetland system. The COD and BOD5 of the wastewater reduced by 83% and 42%, and the reduction rate of Cr(VI) was 96% separately in the photocatalysis-constructed wetland combination method system. At the same time, the changes in plant parameters under these two systems were studied, and the results showed that the addition of photocatalyst and hydrogen peroxide to constructed wetlands did not affect the normal indicators of plant growth. The results showed that the photocatalysis-constructed wetland combination method not only reduced the treatment time greatly, but also improved the quality of the treated wastewater significantly.

DECOLOURIZATION AND COD REMOVAL OF WASEWATER FROM ETHANOL PRODUCTION PROCESS FROM MOLASSES BY COAGULANTION USING INORGANIC ALUM

2010 ◽  
Vol 13 (3) ◽  
pp. 92-102
Author(s):  
Trung Duc Le
Keyword(s):  
Ethanol Production ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Treatment Processes ◽  
Physico Chemical ◽  
Biological Methods ◽  
Treatment Step ◽  
Main Material

The industrial production of ethanol by fermentation using molasses as main material that generates large quantity of wastewater. This wastewater contains high levels of colour and chemical oxygen demand (COD), that may causes serious environmental pollution. Most available treatment processes in Vietnam rely on biological methods, which often fail to treat waste water up to discharge standard. As always, it was reported that quality of treated wastewater could not meet Vietnameses discharge standard. So, it is necessary to improve the treatment efficiency of whole technological process and therefore, supplemental physico-chemical treatment step before biodegradation stage should be the appropriate choice. This study was carried out to assess the effect of coagulation process on decolourization and COD removal in molasses-based ethanol production wastewater using inorganic coaglutant under laboratory conditions. The experimental results showed that the reductions of COD and colour with the utilization of Al2(SO4)3 at pH 9.5 were 83% and 70%, respectively. Mixture FeSO4 – Al2(SO4)3 at pH 8.5 reduced 82% of colour and 70% of COD. With the addition of Polyacrylamide (PAM), the reduction efficiencies of colour, COD and turbidity by FeSO4 – Al2(SO4)3 were 87%, 73.1% and 94.1% correspondingly. It was indicated that PAM significantly reduced the turbidity of wastewater, however it virtually did not increase the efficiencies of colour and COD reduction. Furthermore, the coagulation processes using PAM usually produces a mount of sludge which is hard to be deposited.

scholarly journals Impact of Partially Treated Wastewater on Downstream Water Quality of Notwane River in Botswana

2018 ◽  
pp. 1-9
Author(s):  
Gilbert K. Gaboutloeloe ◽  
Gugu Molokwe ◽  
Benedict Kayombo
Keyword(s):  
Water Quality ◽  
Pearson Correlation ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Treated Wastewater ◽  
Nitrate N ◽  
River Stretch ◽  
Ph Range ◽  
The Impact

The impact of partially treated wastewater on the water quality of Notwane river stretch in the Gaborone region of Botswana was investigated. Water samples collected at effluent discharge point and three other sampling sites downstream were analyzed for pH, temperature, Biological Oxygen Demand (BOD5), Ammonia-nitrogen (Ammonia-N) and Nitrate-nitrogen (Nitrate-N). Sampling was conducted bi-weekly between February 2013 and April 2013. The ranges of measured parameters were:  pH (7.6-8.5), temperature (22-23ºC), BOD5 (11.2-27.0 mg/l), Ammonia-N (2.4-60.5 mg/l), Nitrate-N (20.6-28.6 mg/l). Analysis of variance, Games-Howel multiple comparisons and Pearson correlation were used to separate variable means. The results signal river non-point pollution due to runoff inflow of organics mainly from land use and domestic waste dumping by nearby dwellings. Temperature, BOD5, and pH range values were all within the Botswana Bureau of Standards (BOBS) limit while the maximum Ammonia-N and Nitrate-N were above BOBS limit by 50.5 mg/l and 6.6 mg/l, respectively. Regulations on indiscriminate waste dumping and discharge standards adherence should be enforced.

scholarly journals Oil refinery wastewater treatment in biofilm reactor followed by sand filtration aiming water reuse

2012 ◽  
Vol 2 (2) ◽  
pp. 84-91 ◽  
Author(s):  
Isabelli N. Dias ◽  
Ana C. Cerqueira ◽  
Geraldo L. Sant'Anna ◽  
Marcia Dezotti
Keyword(s):  
Water Reuse ◽  
Slow Rate ◽  
Combined Treatment ◽  
Oxygen Demand ◽  
Biofilm Reactor ◽  
Oil Refinery ◽  
Treated Wastewater ◽  
Refinery Wastewater ◽  
Oil Refinery Wastewater

Oil refinery wastewater was sequentially treated in a moving-bed biofilm reactor (MBBR) and a slow-rate sand filter (SF) in order to obtain an effluent with adequate characteristics for downstream reverse osmosis (RO) operation. Experiments were conducted in bench scale units and the results showed that the MBBR was able to remove 90% chemical oxygen demand (COD), 75% NH4+, 95% phenols, operating with a hydraulic retention time (HRT) of 9 h. Additional removal of COD (15–40%) and ammonia (30–60%) was achieved in the slow-rate SF that was also effective for removing microorganisms. The silt density index (SDI) of the treated wastewater (4.5) was below the maximum limit recommended for RO operation. The quality of the effluent from the combined treatment system (MBBR+SF) was already adequate for cooling tower make-up. The RO produced an effluent with quality compatible with that required for use in boilers.

Reuse of constructed wetland effluents for irrigation of energy crops

2014 ◽  
Vol 70 (9) ◽  
pp. 1465-1472 ◽  
Author(s):  
S. Barbagallo ◽  
A. C. Barbera ◽  
G. L. Cirelli ◽  
M. Milani ◽  
A. Toscano
Keyword(s):  
Constructed Wetland ◽  
High Reliability ◽  
Wastewater Reuse ◽  
Oxygen Demand ◽  
Arundo Donax ◽  
Energy Crops ◽  
Treated Wastewater ◽  
Miscanthus Giganteus ◽  
Italian Law ◽  
Microbiological Parameters

The aim of this study was to evaluate biomass production of promising ‘no-food’ energy crops, Vetiveria zizanoides (L.) Nash, Miscanthus × giganteus Greef et Deu. and Arundo donax (L.), irrigated with low quality water at different evapotranspiration restitutions. Two horizontal subsurface flow (H-SSF) constructed wetland (CW) beds, with different operation life (12 and 6 years), were used to treat secondary municipal wastewaters for crop irrigation. Water chemical, physical and microbiological parameters as well as plant bio-agronomic characters were evaluated. The results confirm the high reliability of CWs for tertiary wastewater treatment given that the H-SSF1 treatment capacity remained largely unchanged after 12 years of operation. Average total suspended solids, chemical oxygen demand and total nitrogen removal for CWs were about 68, 58 and 71%, respectively. The Escherichia coli removal was satisfactory, about 3.3 log unit for both CW beds on average, but caution should be taken as this parameter did not achieve the restrictive Italian law limits for wastewater reuse. The average above-ground dry matter productions were 7 t ha−1 for Vetiveria zizanoides, 24 t ha−1 for Miscanthus × giganteus and 50 t ha−1 for Arundo donax. These results highlight attractive biomass yield by using treated wastewater for irrigation with a complete restitution of evapotranspiration losses.

scholarly journals Evaluation of Hybrid Constructed Wetland Performance and Reuse of Treated Wastewater in Agricultural Irrigation

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1165
Author(s):  
Michal Šereš ◽  
Petra Innemanová ◽  
Tereza Hnátková ◽  
Miloš Rozkošný ◽  
Alexandros Stefanakis ◽  
...  
Keyword(s):  
Czech Republic ◽  
Constructed Wetland ◽  
Public Perception ◽  
Oxygen Demand ◽  
Common Garden ◽  
Treated Wastewater ◽  
Total N ◽  
The Czech Republic ◽  
Fertilizing Effect ◽  
Reuse Of Treated Wastewater

Agriculture is being negatively affected by the decrease in precipitation that has been observed over the last few years. Even in the Czech Republic, farmers are being urged to irrigate their fields despite the fact that sources of water for irrigation are rapidly being depleted. This problem might be partially solved via the reuse of treated wastewater in certain agricultural sectors. However, the public perception of the reuse of wastewater remains negative primarily due to unknown risks to the environment and public health. To overcome this barrier, a semi-operated irrigation field was established at Kostelec nad Ohří in the Central Bohemian region of the Czech Republic and planted with common garden crops such as tomatoes (Lycopersicon esculentum), potatoes (Solanum tuberosum) and lettuces (Lactuca sativa L.) irrigated with two different water sources, i.e., treated wastewater from a local nature-based treatment system, a hybrid constructed wetland (HCW), and local fresh water from well. The HCW was put into operation in 2017 and was reconstructed in 2018 and includes both horizontal and vertical flow beds; the trial irrigation field was added in the same year. The reconstruction of the facility significantly enhanced the removal efficiency with respect to all monitored parameters, e.g., biochemical oxygen demand (BOD5), chemical oxygen demand (COD), N–NH4+, total N and the suspended solids (TSS), except for total P. The HCW also ensured the significant removal of several observed pathogenic microorganisms (E. coli, intestinal enterococci and thermotolerant coliforms). During the 2018 and 2019 growing seasons, we observed the significantly enhanced growth of the crops irrigated with wastewater from the HCW due to the fertilizing effect. The risks associated with the contamination of crops irrigated with treated water are not negligible and it is necessary to pay sufficient attention to them, especially when introducing irrigation with wastewater into practice.

scholarly journals Application of horizontal flow constructed wetland and solar driven disinfection technologies for wastewater treatment in India

2018 ◽  
Vol 13 (3) ◽  
pp. 469-480 ◽  
Author(s):  
Virendra Kumar Mishra ◽  
Philipp Otter ◽  
Reetika Shukla ◽  
Alexander Goldmaier ◽  
J. A. Alvarez ◽  
...  
Keyword(s):  
Constructed Wetland ◽  
Oxygen Demand ◽  
Free Water ◽  
Treated Wastewater ◽  
Electrolytic Production ◽  
Soil Enrichment ◽  
Physico Chemical ◽  
Treated Sewage ◽  
Gravity Driven ◽  
Filter Bed

Abstract The present study was conducted to treat primary and secondary treated sewage for its reuse in irrigation, soil enrichment and aquaculture activities. The study involves treatment of this sewage through a subsurface horizontal gravity-fed gravel filter bed with an area of 35 m2. The effluent was then subjected to filtration by zeolite medium and disinfection by inline electrolytic production of chlorine. In order to provide pathogen-free water, an anodic oxidation (AO) disinfection system was implemented, treating a flow of up to 10 m3/d. The gravity-driven constructed wetland and solar-driven disinfection systems were evaluated for their treatment capacity for various physico-chemical and biological parameters. The wetland removed almost 84% of the nitrate (NO3−) and 77% of the phosphate (PO43−). Five-day biological oxygen demand was reduced from 48 mg/l to 10 mg/l from the secondary treated wastewater. The wetland was able to remove 65–70% of bacteria in the wastewater, whereas the AO disinfection system removed the bacterial content to below the detection limit. The implementation of the systems will provide a suitable option for the treatment of wastewater in a very economical and sustainable way.

scholarly journals Treatment of Tannery Wastewater with Vibratory Shear-Enhanced Processing Membrane Filtration

Separations ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 20 ◽  
Author(s):  
Anastasios Zouboulis ◽  
Efrosyni Peleka ◽  
Anastasia Ntolia
Keyword(s):  
Vibration Amplitude ◽  
Membrane Filtration ◽  
Suspended Solids ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Treated Wastewater ◽  
Treatment Efficiency ◽  
Membrane Unit ◽  
Membrane Type

The performance of a vibratory shear-enhanced process (VSEP) combined with an appropriate membrane unit for the treatment of simulated or industrial tannery wastewaters was investigated. The fundamental operational and pollution parameters were evaluated, i.e., the membrane type, the applied vibration amplitude, as well as the removal rates (%) of tannins, chemical oxygen demand (COD), Ntotal, turbidity and color. Regarding the system’s treatment efficiency, specific emphasis was given towards the removal of organics (expressed as COD values), suspended solids (SS), conductivity (as an index of dissolved solids’ presence) and total nitrogen. The removal of organic matter in terms of COD exceeded 75% for all the examined cases. The quality of treated wastewater was affected not only by the membrane specific type (i.e., the respective pore diameters), but also by the applied vibration amplitude. Furthermore, an average 50% removal rate, regarding the aforementioned parameters, was observed both for the simulated and the industrial tannery wastewaters during the microfiltration (MF) experiments. That removal rate was further increased up to 85%, when ultrafiltration (UF) was applied, and up to 99% during the Reverse Osmosis (RO) experiments, considering the maximum applied vibration amplitude (31.75 mm).

scholarly journals Effects of Pre-Treatment Using Plasma on the Antibacterial Activity of Mushroom Surfaces

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1888
Author(s):  
Sarmistha Mitra ◽  
Mayura Veerana ◽  
Eun-Ha Choi ◽  
Gyungsoon Park
Keyword(s):  
Lipid Peroxidation ◽  
Atmospheric Pressure ◽  
Treatment Time ◽  
Reduction Rate ◽  
Atmospheric Pressure Plasma ◽  
Bacterial Attachment ◽  
Pressure Plasma ◽  
Attached Bacteria ◽  
Pre Treatment

Although non-thermal atmospheric pressure plasma is an efficient tool for preventing post-harvest microbial contamination, many studies have focused on the post-treatment of infected or contaminated foods. In this study, we examined the antimicrobial quality of mushrooms pre-treated with a non-thermal atmospheric pressure plasma jet (NTAPPJ) or plasma-treated water (PTW). The CFU (Colony Forming Unit) number of Escherichia coli inoculated on surfaces of mushrooms pre-treated with NTAPPJ or PTW was significantly reduced (about 60–75% for NTAPPJ and about 35–85% for PTW), and the reduction rate was proportional to the treatment time. Bacterial attachment and viability of the attached bacteria were decreased on NTAPPJ-treated mushroom surfaces. This may be caused by the increased hydrophilicity and oxidizing capacity observed on NTAPPJ-treated mushroom surfaces. In PTW-treated mushrooms, bacterial attachment was not significantly changed, but death and lipid peroxidation of the attached bacteria were significantly increased. Analysis of mushroom quality showed that loss of water content was greater in mushrooms treated with NTAPPJ compared to that in those with no treatment (control) and PTW treatment during storage. Our results suggest that pre-treatment with NTAPPJ or PTW can improve the antibacterial quality of mushroom surfaces by decreasing bacterial attachment (for NTAPPJ) and increasing bacterial lipid peroxidation (for both NTAPPJ and PTW).

scholarly journals Integrated Constructed Wetland (ICW) System a Sustainable Novel Technique for Urban Wastewater Management

2021 ◽  
Author(s):  
Jeyaraman Sethuraman Sudarsan ◽  
Ramasamy Annadurai ◽  
Subramanian Nithiyanantham
Keyword(s):  
Constructed Wetland ◽  
Typha Latifolia ◽  
Oxygen Demand ◽  
Impurity Level ◽  
Wastewater Management ◽  
System A ◽  
Reduction Efficiency ◽  
Integrated Constructed Wetland ◽  
Wetland System ◽  
One Year

Abstract The present study focuses on various aspects of Integrated Constructed Wetland System (ICW) systems with reference to its efficiency, and eco-friendliness in the treatment of domesticwastewater. The biological oxygen demand (BOD) impurity level is in the ranged from 383 mgl-1 to 248 mgl-1, chemical oxygen demand (COD)420 mgl-1 to 340 mgl-1, Total Phosphorus (TP) 10.2 mgl-1 to 5 mgl-1 and Total Nitrogen (TN) 18.9 mgl-1 to 14.8 mgl-1 respectively over a period of one year (SRM University). The influent contaminants are degradable in nature especially with high TP and TN concentrations. Six units of Constructed Wetland System (ICW)units are built with uniform dimensions of 2×1× 0.9 m based on EPA and TVA.The wetland plants chosen areTypha Latifolia and Phragmites Australis. Among the wetland units, Typha oriented units are observed to perform better with a reduction efficiency of 87% for BOD, 86% for COD, 70% for TP and 78% for TN proving that Typha Latifoliais a better aquatic plant for overall wastewater treatment. The removal efficiency increases with time and reaches maximum in 192 hrs. To substantiate the experimental study output, Statistical analysis (ANOVA) and multiple regression analysis with normality plot has carried out. It isevident that thepercentage removal of many parameters especially organic parameters over a period of time in treating with different wetland units is highly significant.

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