scholarly journals Phycoremediation of textile wastewater using indigenous microalgae

2018 ◽  
Vol 13 (2) ◽  
pp. 274-284 ◽  
Author(s):  
Tadele Assefa Aragaw ◽  
Abraham M. Asmare

Abstract The recognition that environmental pollution is a worldwide threat to public health and environmental degradation has given rise to new initiatives for environmental restoration for both economic and ecological reasons. There are several methods to treat the dye contaminated industrial wastewater; of which biological treatment methods are economical and environmentally friendly. The bacteria and fungi remediation of dye pollutants has been well characterized over a period of more than 30 years. So, finding other biological methods in addition to bacteria and fungi is great important in the world. As a result, investigating and evaluating Phycoremediation techniques of dye wastewater (bioremediation using Microalgae) have gained a great deal of attention because of their versatility and capacity than bacteria and fungi. The aim of the research is to study Phycoremediation of Textile Wastewater Using indigenous Microalgae. Physico-chemical parameters such as color, pH, total dissolved solid (TDS), biochemical oxygen demand (BOD) and chemical oxygen demand of the waste were determined with ASTM standard methods before and after bioremediation. Photo bioreactor systems were used for Phycoremediation treatment techniques. PH, incubation time and temperature effects were determined on a photo bioreactor treatment and optimal experimental condition was ascertained. Instrumental analytical techniques (UV-Vis, FTIR) were used to determine percent decolorizations of dye wastewater before and after bioremediation; and the actual break down of the dye functional groups. The maximum reductions of the basic parameters; COD, BOD and TDS were obtained 91.50%, 91.90% and 89.10% respectively. The optimum operating conditions in the photo bioreactor system were found incubation time 20 days, 30°C; with 10% of inoculums at a pH of 8. Under these conditions, a maximum of 82.6% decolorization was achieved in 20 days. The experimental investigations evidently tell us algae undoubtedly have the potential to rapidly, efficiently and effectively remove dyes wastewater.

2010 ◽  
Vol 61 (2) ◽  
pp. 491-498 ◽  
Author(s):  
P. A. Alves ◽  
G. R. P. Malpass ◽  
H. D. Johansen ◽  
E. B. Azevedo ◽  
L. M. Gomes ◽  
...  

In the present study, photo-assisted electrochemical degradation of real textile wastewater was performed. Degradation assays were performed at constant current (40 mA cm−2) in a combined electro/photochemical flow-cell using a Ti/Ru0.3Ti0.7O2 DSA® type electrode. The results show that the method is capable of removing color and chemical oxygen demand (COD) from the effluent. Additionally, the effect of initial pH and type of supporting electrolyte (Na2SO4 or NaCl) was investigated. The principal figures of merit used in this study were COD removal and color removal (605 nm). The results show that up to 72% color and up to 59% COD removal in 120 min is possible under the operating conditions employed. Studies of the phytotoxicity of the wastewater before and after the photo-assisted degradation assays are also presented and the results demonstrate that the toxicity of the effluent is dependent on the length of electrolysis time and the treatment procedure employed.


2015 ◽  
Vol 73 (1) ◽  
pp. 102-112 ◽  
Author(s):  
Ahmed H. Hilles ◽  
Salem S. Abu Amr ◽  
Rim A. Hussein ◽  
Anwar I. Arafa ◽  
Olfat D. El-Sebaie

The objective of this study was to investigate the performance of employing H2O2 reagent in persulfate activation to treat stabilized landfill leachate. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as persulfate and H2O2 dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following two responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD) and NH3-N removal. The obtained optimum conditions included a reaction time of 116 min, 4.97 g S2O82−, 7.29 g H2O2 dosage and pH 11. The experimental results were corresponding well with predicted models (COD and NH3-N removal rates of 81% and 83%, respectively). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as persulfate only and H2O2 only, to evaluate its effectiveness. The combined method (i.e., /S2O82−/H2O2) achieved higher removal efficiencies for COD and NH3-N compared with other studied applications.


Author(s):  
Erin E Powell ◽  
Gordon A Hill

The operation of continuously stirred tank bioreactors (CSTBs) at minimum cost is a major concern of operators. In this work, a CSTB design strategy is presented where impeller stirring speed and aeration rate are optimized to meet the oxygen demand of growing cells, simultaneously minimizing the capital and operating cost. The operating cost is limited to the cost of utilities. The optimization scheme assumes a given fermentor tank size, and that the properties of the culture medium and the oxygen respiratory requirements of the microorganisms being cultivated are known. It is possible to choose between two different turbine impellers during the design process. The equations, constraints, and the CSTB design strategy employed by the program are described. The effect of microbial species, ions in the culture medium, impeller style, as well as changing CSTB size and biomass input density on the optimum operating conditions, is examined. The mass transfer coefficient, gas holdup, mixing speed, and aeration rate are all reported at optimized cost conditions. A study of the effects of various parameters on the CSTB design are shown.


2018 ◽  
Vol 20 (3) ◽  
pp. 449-457

<p>This study explored the best-operating conditions for a novel electrocoagulation (EC) reactor with the rotating anode for textile wastewater treatment. The influence of operating parameters like inter-electrode distance (IED), current density (CD), temperature, pH, operating time (RT), and rotation speed on the removal efficiency of the contaminant was studied. A comparative study was done using conventional model with static electrodes in two phases under same textile wastewater The findings revealed that the optimal conditions for textile wastewater treatment were attained at RT = 10 min, CD = 4 mA/cm2, rotation speed = 150 rpm, temperature = 25oC, IED = 1cm, and pH = 4.57. The removal efficiencies of colour, biological oxygen demand (BOD), turbidity, chemical oxygen demand (COD), and total suspended solid (TSS) were 98.50%, 95.55%, 96%, 98% and 97.10% within the first 10 min of the reaction. The results of the experiment reveal that the newly designed reactor incorporated with cathode rings and rotated anode impellers provide a superior treatment efficiency within a short reaction time. The novel EC reactor with a rotating anode significantly enhanced textile wastewater treatment compared to the conventional model. The values of adsorption and passivation resistance validated the pollutants removal rate.</p>


2017 ◽  
Vol 18 (2) ◽  
pp. 71-78
Author(s):  
Ibrahim Adebayo Bello

Effluents from dye and textile industries are highly contaminated and toxic to the environment. High concentration of non-biodegradable compounds contributes to increased biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of the wastewater bodies.  Dyes found in wastewater from textile industries are carcinogenic, mutagenic or teratogenic. Biological processes involving certain bacteria, fungi, activated carbon and carbon nanotubes (CNTs) are promising methods for treating the waste water. These methods are either inefficient or ineffective.  These complexities necessitates search for new approaches that will offset all the shortcomings of the present solutions to the challenges faced with textile wastewater management. This article reviews the past and recent methods used in the treatment of the textile dye wastewater and the future opportunities for efficient treatment of textiles wastewaters.


2012 ◽  
Vol 47 (1) ◽  
pp. 77-82 ◽  
Author(s):  
SH Rahman ◽  
SMN Islam ◽  
N Kaiser ◽  
Md M Rahman

Karnopara Canal water containing high COD values (1050 mg O2/L) was treated by electrocoagulation (EC) method covering a wide range of operating conditions such as, water pH, internal electrode distances, final pH, supplying 30V electricity for constant time period (30 minutes) through same electrode material (Al electrode). The effects of different operating parameters on the efficiency of the process were examined. Targeting to reduce the COD value within the recommended limit (200 mg O2/L), this research work was emphasized on EC treatment at the simplest and cheapest way. The batch experiment results showed that the high COD contained canal water can be effectively treated using electrocoagulation. The overall COD removal efficiencies have been obtained at 87.3%, under optimum operating conditions. Taking all the factors into account, it was found that polluted Karnopara canal water can be treated using EC consisting of Al electrodes without pre-adjustment of pH at laboratory. Therefore, EC technique to reduce high COD from canal surface water is found effective, cheaper and environmental friendly. DOI: http://dx.doi.org/10.3329/bjsir.v47i1.10728 Bangladesh J. Sci. Ind. Res. 47(1), 77-82, 2012


2013 ◽  
Vol 5 (2) ◽  
pp. 475-481 ◽  
Author(s):  
Arun Kumar Sharma ◽  
A. K. Chopra

The present investigation observed the effect of current density (CD), operating time (OT), inter electrode distance (IED), electrode area (EA), initial pH and settling time (ST) using Fe-Fe electrode combination on the removal of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) from biologically treated municipal wastewater (BTMW) of Sewage Treatment Plant (STP). The maximum removal of COD (92.35%) from BTMW was found with the optimum operating conditions of CD (2.82 A/m2), OT (40 mins.), IED (0.5 cm), EA (160 cm2), initial pH (7.5) and ST (60 min.), while the maximum removal of BOD (84.88%) was found with the ST (30 min.) at the same operating conditions. There was no need of pH adjustment of the BTMW during ET as the optimal removal efficiency was close to the pH of 7.5. Under optimal operating conditions, the operating cost was found to be 54.29 Rs./m3 / 1.08 US$/m3 in terms of the electrode consumption (78.48 x 10-5 kg Al/m3 ) and energy consumption (108.48 Kwh/m3).


Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 66
Author(s):  
Ziba Barati ◽  
Sajid Latif ◽  
Sebastian Romuli ◽  
Joachim Müller

In this study, the effect of enzymatic pre-treatment and the size of cassava tubers on mechanical peeling was examined. Cassava tubers were sorted based on their mass as small, medium and large. Viscozyme® L and an abrasive cassava peeling machine was used for the enzymatic pre-treatment and the mechanical peeling, respectively. Response surface methodology (RSM) was used to investigate the effect of the enzyme dose (0.5–1.9 mL g−1), incubation time (1.5–6 h), peeling time (1.5–4.5 min) and size of the tubers (small, medium and large) on the peeling process. Peeled surface area (PSA) and peel loss (PL) were measured as main responses in RSM. Results showed that the PSA and PL were significantly (p < 0.05) influenced by the enzyme dose, incubation time and peeling time. The size of tubers only had a significant impact on the PSA. The optimum operating conditions for different sizes of tubers were found and validated. Under optimum conditions, the PSA of the large tubers (89.52%) was significantly higher than the PSA of the medium and small tubers (p < 0.05). Application of enzymatic pre-treatment can improve the mechanical peeling process especially for larger cassava tubers.


DYNA ◽  
2016 ◽  
Vol 83 (196) ◽  
pp. 80-85 ◽  
Author(s):  
Jose Herney Ramirez ◽  
Hugo Ricardo Zea

<p>Iron-doped TiO<sub>2</sub> catalysts were prepared by impregnation in order to study their photocatalytic activity in the treatment of wastewater from the textile industry. Characterization of the catalysts before and after reaction was performed using techniques including total surface area measurement, X-Ray diffraction and elemental analysis via X-Ray fluorescence. Varying pH conditions, H<sub>2</sub>O<sub>2</sub> concentrations and catalyst quantities were evaluated during the photocatalytic reactions. Fe-TiO<sub>2</sub> catalysts were shown to be highly active in the reduction of chemical oxygen demand (% COD) and % color reduction in the water treated.</p>


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