scholarly journals Comparative study for the treatment of domestic wastewater using Chlorella Vulgaris

2020 ◽  
Author(s):  
Nandini Moondra ◽  
Namrata Jariwala ◽  
Robin A Christian

Abstract Tertiary treatment using chemicals frequently prompts secondary contamination of sludge, making additional issues of safe disposal. Thus, vitality and cost required for tertiary treatment of wastewater stay an issue for industries and municipalities. In this study, different microalgal concentrations 360 mL (20%), 450 mL (25%), 540 mL (30%), 630 mL (35%), 720 mL (40%) and 810 mL (45%) were studied to treat domestic wastewater for 11 hours of detention time for both filtered and non-filtered effluent. During the study, removal was observed in Total Solids (TS), Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Electrical Conductivity (EC), phosphate, ammonia and Chemical Oxygen Demand (COD) for all the microalgal concentrations mentioned. 30% microalgal concentration showed maximum removal efficiency among different microalgal concentrations studied. Maximum removal efficiency found in non-filtered effluents when treated with 30% microalgal concentration was 96.60, 91.73 and 84.71% respectively for ammonia, phosphate and COD concentration. However, the removal efficiency increased to 97.62, 92.47 and 88.75% respectively for ammonia, phosphate and COD in the case of filtered effluents. In the case of TSS and EC, removal efficiency reached up to 30.87 and 24.31% respectively for non-filtered effluents while it was 48.00 and 25.88% respectively, for the filtered effluents. One-way ANOVA was also conducted to determine the statistical significance of the study. The study showed that an algae-based system could accomplish a more affordable and environment-friendly way to treat domestic wastewater without tertiary treatment to a desirable limit.

2020 ◽  
Author(s):  
Nandini Moondra ◽  
Namrata Jariwala ◽  
Robin A Christian

Abstract Tertiary treatment using chemicals frequently prompts secondary contamination of sludge, making other issues of safe disposal. Thus, vitality and cost required for tertiary treatment of wastewater stay an issue for industries and municipalities. In this study, different microalgal concentrations (20%, 25%, 30%, 35%, 40% and 45%) were studied to treat domestic wastewater at 11 hours HRT for both filtered and non- filtered effluent. During the study, removal was observed in Total Solids (TS), Total Dissolved Solids (TDS), Total Suspended Solids (TSS), Electrical Conductivity (EC), phosphate, ammonia and COD for all the microalgal concentrations mentioned. However, the maximum removal efficiency was observed at 30% microalgal concentration. Maximum removal efficiency found in ammonia, phosphate and COD for non-filtered effluent was 96.60%, 91.73% and 84.71% respectively, whereas, in the case of the filtered sample, removal efficiency reached up to 97.62%, 92.47% and 88.75% for ammonia, phosphate and COD respectively. In the case of solids (specifically TSS) and EC, removal efficiency reached up to 30.87% and 24.31% respectively for non-filtered effluent and was 48.00% and 25.88% in the filtered sample. The study showed that an algae-based system could accomplish more affordable and environment-friendly way to treat domestic wastewater without tertiary treatment to a desirable limit.


2018 ◽  
Vol 78 (9) ◽  
pp. 1879-1892 ◽  
Author(s):  
Md Khalekuzzaman ◽  
Muhammed Alamgir ◽  
Mehedi Hasan ◽  
Md Nahid Hasan

Abstract In this research, a hybrid anaerobic baffled reactor (HABR) configuration was proposed consisting of a front sedimentation chamber and four regular baffled chambers followed by two floated filter media chambers for the treatment of domestic wastewater. Performance comparison of uninsulated and insulated HABRs was carried out operating at warm temperature (18.6–37.6 °C) under variable HRTs (30 h and 20 h). The study suggests that almost similar chemical oxygen demand (91% vs 88%), total suspended solids (90% vs 95%), turbidity (98% vs 97%), and volatile suspended solids (90% vs 93%) removal efficiencies were obtained for uninsulated and insulated HABRs. Higher removal of total nitrogen (TN) of 41%, NH4+-N of 44%, and NO3−-N of 91% were achieved by the insulated HABR compared to TN of 37%, NH4+-N of 36%, and NO3−-N of 84% by the uninsulated HABR, whereas lower PO43− removal efficiency of 17% was found in the insulated HABR compared to 24% in the uninsulated HABR. This indicated insulation increased nitrogen removal efficiencies by 4% for TN, 8% for NH4+-N and 7% for NO3−-N, but decreased PO43−removal efficiency by 7%.


2004 ◽  
Vol 49 (5-6) ◽  
pp. 281-288 ◽  
Author(s):  
S.J. Kim ◽  
P.Y. Yang

A two-stage entrapped mixed microbial cell (2SEMMC) process which separates nitrification and denitrification phases by the installation of the anoxic and oxic EMMC reactors packed with EMMC carriers was operated with 6, 4, 3, and 2 hours of hydraulic retention time (HRT) using simulated domestic wastewater. The activated sludge was immobilized using cellulose acetate for the EMMC carriers. Similar soluble chemical oxygen demand (SCOD) removal efficiencies of 90-97% were observed for all HRTs (SCOD loading rate of 0.84-2.30 g/L/d) applied. In order to achieve more than 80 % of TN removal efficiency, the HRT should be maintained higher than 4 hours (less than 0.24 g/L/d of TN loading rate). Denitrification was a rate-limiting step which controlled overall TN removal efficiency at TN loading rate of 0.15-0.31 g/L/d although nitrification efficiencies achieved 97-99 %. The effluent TSS of less than 25 mg/L in the 2SEMMC process was maintained at the SCOD loading rate of less than 1.23 g/L/d with back-washing intervals of 5 and 10 days in the anoxic and oxic EMMC reactors, respectively. The minimum HRT of 4 hours is required for high removal efficiencies of organics (average 95.6 %) and nitrogen (average 80.5 %) in the 2SEMMC process with 3 times of recirculation ratio.


2021 ◽  
Author(s):  
Vanitha Thammaiah ◽  
Manjunatha Hebbara ◽  
Manjunatha Mudukapla Virupakshappa

Abstract An experiment with different filterbeds and macrophytes was carried-out to study their phytoremediation capacity on the efficiency of domestic wastewater treatment through constructed wetland (CW) during November to March, 2017-18 at University of Agricultural Sciences, Dharwad campus, Karnataka, India. Twenty treatment combinations involving five types of filterbeds (FB-1: gravel, FB-2: gravel-sand-gravel, FB-3: gavel-sand-brick-gravel, FB-4: gravel-sand-charcoal-gravel and FB-5: gravel-sand-(charcoal+brick)-gravel) and four macrophytes (MP-1: Typha latifolia, MP-2: Brachiaria mutica, MP-3: Canna indica and MP-4: Phragmites sps.) were evaluated for treating domestic wastewater. After 120 days from start, across treatment combinations, water electrical conductivity (EC), total dissolved and suspended solids (TDS-TSS), biological oxygen demand (BOD), chemical oxygen demand (COD), sodium, sodium adsorption ratio (SAR), residual sodium carbonate (RSC), bicarbonates, total nitrogen-phosphorus-potassium (N-P-K) and boron (B) were reduced by more than 40 per cent due to wetland treatment. The system enhanced the mineralization of organic nitrogen to ammoniacal nitrogen (NH4+-N) and nitrate nitrogen (NO3-N) fractions. Among filterbeds, Type-5 caused higher reduction in pH, EC, BOD, COD and Organic-N while, Type-4 proved efficient in removing total solids and lowering pH in the sewage effluent. The Type-3 filterbed removed more suspended solids, potassium and ammoniacal nitrogen. Among the macrophytes, Brachiaria (paragrass) removed more nitrogen and potassium while, Phragmites removed more nitrogen, phosphorus and boron. The flexibility of implementation allows the CW to be adapted to different sites with different configurations, being suitable as main, secondary or tertiary treatment stage.


2019 ◽  
Vol 6 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Abdul Aziz Hamidi ◽  
Syed Zainal Sharifah Farah Fariza ◽  
Alazaiza Motasem Y.D

Landfill leachate is highly polluted and generated as a result of water infiltration through solid waste produced domestically and industrially. This study investigated the applicability of the response surface methodology (RSM) to optimize the removal performances of chemical oxygen demand (COD), color, and suspended solids (SS) from landfill leachate by coagulation process using Tin tetrachloride pentahydrate. The leachate samples were collected from Alor Pongsu Landfill (APLS) in Perak, Malaysia. Before starting the experiments, general characterization was carried out for raw leachate samples to investigate their physical and chemical properties. The effects of the dosage and pH of SnCl4 on the removal performances were evaluated as well. An ideal experimental design was performed based on the central composite design (CCD) by RSM. In addition, this RSM was used to evaluate the effects of process variables and their interaction toward the attainment of their optimum conditions. The statistical design of the experiments and data analysis was resolved using the Design-Expert software. Further, the range of coagulant dosage and pH was selected based on a batch study which was conducted at 13000 mg/L to 17000 mg/L of SnCl4 and pH ranged from 6 to 10. The results showed that the optimum pH and dosage of SnCl4 were 7.17 and 15 g/L, respectively, where the maximum removal efficiency was 67.7% for COD and 100% for color and SS. The results were in agreement with the experimental data with a maximum removal efficiency of 67.84 %, 98.6 %, and 99.3%, for COD, color, and SS, respectively. Overall, this study verified that the RSM method was viable for optimizing the operational condition of the coagulation-flocculation process.


2019 ◽  
Vol 6 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Veymar G. Tacias-Pascacio ◽  
Abumalé Cruz-Salomón ◽  
José H. Castañón-González ◽  
Beatriz Torrestiana-Sanchez

Background: Wet coffee processing consists of the removal of the pulp and mucilage of the coffee cherry. This process generates a large amount of acidic wastewater which is very aggressive to the environment because of its high content of recalcitrant organic matter. Therefore, treatment is necessary before discharge to water bodies. Because of this reason, this study aimed to evaluate the organic matter removal efficiency in an Anaerobic Baffled Bioreactor (ABR) coupled to a Microfiltration Membrane (MF) system as a new eco-friendly option in the treatment of wet Coffee Processing Wastewater (CPWW). Methods: Two systems (S1 and S2) were evaluated at Hydraulic Retention Times (HRT) of 59 h and 83 h, respectively. Both systems were operated at mesophilic conditions, at a Transmembrane Pressure (TMP) of 50 kPa during 1800 h. Results: The S2 generated higher organic matter removal efficiency, reaching removal values of turbidity of 98.7%, Chemical Oxygen Demand (COD) of 81%, Total Solids (TS) of 72.6%, Total Suspended Solids (TSS) of 100%, and Total Dissolved Solids (TDS) of 61%, compared with the S1. Conclusion: The S2 represents a new eco-friendly alternative to treat CPWW and reduce its pollutant effect.


2015 ◽  
Vol 5 (3) ◽  
pp. 293-300 ◽  
Author(s):  
N. H. Abdurahman ◽  
Y. M. Rosli ◽  
N. H. Azhari ◽  
Hayder A. Bari

Direct discharge of slaughterhouse wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD), total suspended solids (TSS) and biochemical oxygen demand. In this study, an ultrasonic-assisted membrane anaerobic system was used as a novel method for treating slaughterhouse wastewater. Six steady states were achieved, using concentrations of 7,800–13,620 mg/l for mixed liquor suspended solids and 5,359–11,424 mg/l for mixed liquor volatile suspended solids (MLVSS). Kinetic equations were used to describe the kinetics of treatment at organic loading rates of 3–11 kg COD/m3/d. The removal efficiency of COD was 94.8–96.5% with hydraulic retention times of 308.6–8.7 days. The growth yield coefficient was found to be 0.52 g VSS/g. COD was 0.21 d−1 and methane gas production rate was 0.24–0.56 l/g COD/d. Steady-state influent COD concentrations increased from 8,000 mg/l in the first steady state to 25,400 mg/l in the sixth steady state. The minimum solids retention time, θcmin obtained from the three kinetic models was 6–14.4 days. The k values were 0.35–0.519 g COD/g VSS.d and μmax values were between 0.26 and 0.379 d−1. The solids retention time decreased from 600 to 14.3 days. The complete treatment reduced the COD content and its removal efficiency reached 94.8%.


2021 ◽  
Vol 27 (1) ◽  
pp. 200436-0
Author(s):  
Deepa Minakshi ◽  
Pradeep Kumar Sharma ◽  
Anju Rani

This study deals with the dairy wastewater treatment using laboratory scale vertical flow (VF) constructed wetlands with the <i>Canna indica</i> plantation over wetland beds due to phytoremediation capabilities. Three laboratory scale VF CWs (CW-A, CW-B and CW-C) each with an area of 0.135 m2 filled with gravel (CW-A: 20 mm; CW-B:10 mm gravel) and sand (CW-C) receiving 0.04 m3 d-1 dairy wastewater were operated for the wastewater purification. Each unit was operated at three hydraulic retention times (HRTs) i.e. 12 h, 24 h and 48 h for assessing its effect on wastewater purification . Among all units, removal rates fluctuated as: total suspended solids (TSS): 64.2–74.5%; biochemical oxygen demand (BOD): 45.3 – 63.1%; ammonium nitrogen (NH4–N): 29.6 – 56.5% and phosphate phosphorous (PO4–P): 20.5 – 57.8% at different HRTs. Increase in HRT showed better removal of pollutants in all CWs. Moreover, maximum removal of pollutants excluding TSS and NH4-N was achieved in CW-B at 48 h HRT. CW-B with similar HRT provided maximum removal of PO4-P (57.8%), BOD (63.1%) and chemical oxygen demand (COD): 67.4%. Increase in the size of filter media, from sand (0.25 mm) to 20 mm gravel resulted in higher removal of NH4 -N from wastewater.


2018 ◽  
Vol 7 (4.35) ◽  
pp. 22
Author(s):  
Gasim Hayder ◽  
Puniyarasen Perumulselum ◽  
Hitham Alhussian

Fixed bed biofilm reactors were evaluated with three different arrangements of bio-balls. The performance of different arrangements was evaluated based on chemical oxygen demand (COD), total suspended solid (TSS) and mixed liquor suspended solid (MLSS). The three rectors were fabricated and operated in lab scale model with real domestic wastewater. Considering the TSS removal efficiency, arrangement one was the best followed by arrangement two and arrangement three. While for COD, arrangement one recorded the highest removal efficiency followed by arrangement two and column. The average COD concentration for arrangement one was 23 while for arrangement two and arrangement three was 25 and 36 mg/l respectively. The overall average effluent TSS concentrations for the arrangement one, two and three were 25, 32 and 45 mg/l respectively. TSS and COD removal was almost the same for arrangement one and arrangement two but arrangement one has the highest among them, and all removal is acceptable under Malaysian standards. Besides that, all the three arrangements have the differences in terms of maintenance and installation. There was no clogging occurred in all the three arrangements.


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