scholarly journals Coagulation and electrocoagulation for co-treatment of stabilized landfill leachate and municipal wastewater

2017 ◽  
Vol 8 (2) ◽  
pp. 234-243 ◽  
Author(s):  
Mohini Verma ◽  
R. Naresh Kumar

Abstract Landfill leachate and municipal wastewater at various ratios (1:20, 1:10, 1:7 and 1:5) were subjected to coagulation and electrocoagulation (EC). Alum was used in conventional coagulation at pH 6 and aluminum plate as electrode was used in EC at a current density of 386 A/m2 with 5 cm inter electrode spacing. Treatment efficiency was assessed from removal of chemical oxygen demand (COD), total suspended solids (TSS), turbidity, ammonia, nitrate and phosphate. At 1:5 ratio of landfill leachate to municipal wastewater, highest COD removal was with 3.8 g/L alum whereas highest turbidity removal was with 3.3 g/L alum during coagulation. EC exhibited almost similar removal efficiency for all the parameters at different ratios tested except for COD which was considerably higher at 1:20 ratio. Aluminum consumption from electrode was 0.7 g/L following EC as compared to 3.8 g/L alum used in coagulation. The amount of sludge produced was found to be higher with EC as compared to coagulation which could be due to the fact that the electrochemical method was performed for a longer duration than conventional coagulation. For minimal sludge generation, EC reaction time should be ∼30 min. Further studies with EC process on costing and sludge generation will help to advance the technology for wastewater treatment.

2016 ◽  
Vol 51 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Kshitij Ranjan ◽  
Shubhrasekhar Chakraborty ◽  
Mohini Verma ◽  
Jawed Iqbal ◽  
R. Naresh Kumar

Sequencing batch reactor (SBR) was assessed for direct co-treatment of old landfill leachate and municipal wastewater for chemical oxygen demand (COD), nutrients and turbidity removal. Nitrogen removal was achieved by sequential nitrification and denitrification under post-anoxic conditions. Initially, SBR operating conditions were optimized by varying hydraulic retention time (HRT) at 20% (v/v) landfill leachate concentration, and results showed that 6 d HRT was suitable for co-treatment. SBR performance was assessed in terms of COD, ammonia, nitrate, phosphate, and turbidity removal efficiency. pH, mixed liquor suspended solids, mixed liquor volatile suspended solids (MLVSS), and sludge volume index were monitored to evaluate stability of SBR. MLVSS indicated that biomass was able to grow even at higher concentrations of old landfill leachate. Ammonia and nitrate removal efficiency was more than 93% and 83%, respectively, whereas COD reduction was in the range of 60–70%. Phosphate and turbidity removal efficiency was 80% and 83%, respectively. Microbial growth kinetic parameters indicated that there was no inhibition of biomass growth up to 20% landfill leachate. The results highlighted that SBR can be used as an initial step for direct co-treatment of landfill leachate and municipal wastewater.


2021 ◽  
Vol 42 (3(SI)) ◽  
pp. 775-781
Author(s):  
M.M. Hanafiah ◽  
◽  
N.I.H.A. Aziz ◽  
A.A. Halim ◽  
L.S. Shamdin ◽  
...  

Aim: In this study, Ipomoea aquatica and Pistia stratiotes were used to remove total suspended solids, chemical oxygen demand and ammoniacal nitrogen (NH3-N) from the landfill leachate collected at Ampar Tenang Closed Landfill (ATCL) site in Dengkil, Selangor, Malaysia. Methodology: The physico-chemical characteristics of landfill leachate (pH, temperature, NH3-N, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, total dissolved solids, total suspended solids, salinity, electrical conductivity and nitrite as well as selected heavy metals were determined before phytoremediation treatment. Results: The physico-chemical properties of leachate samples were found to be lower as compared to the standards set by the government, except for COD (>100 mg l-1). Heavy metals content, Na, Mg and Fe was high in leachate. It was found that the concentrations of NH3-N, COD and TSS in leachate decreased by 57.64%, 26.85% and 62.05% after treatment with Ipomea aquatica, respectively. Whereas, 61%, 32% and 74.7% removal rate was observed for NH3-N, COD and TSS, post-treatment by Pistia stratiotes. One-way ANOVA analysis for Ipomoea aquatica revealed insignificant difference (p>0.05) but for Pistia stratiotes there was a significant difference (p<0.05) in the reduction of TSS, COD and NH3-N concentrations. Interpretation: Based on the findings, Pistia stratiotes was found more effective than Ipomea aquatica for reducing TSS, COD and NH3-N concentrations from landfill leachate.


2014 ◽  
Vol 70 (12) ◽  
pp. 1941-1947 ◽  
Author(s):  
R. Campos ◽  
F. M. Ferraz ◽  
E. M. Vieira ◽  
J. Povinelli

This study investigated the co-treatment of landfill leachate/domestic wastewater in bench-scale activated sludge (AS) reactors to determine whether the slowly biodegradable organic matter (SBOM) was removed rather than diluted. The AS reactors were loaded with mixtures of raw leachate and leachate that was pretreated by air stripping. The tested volumetric ratios were 0%, 0.2%, 2% and 5%. For all of the tested conditions, the reactors performed better when pretreated leachate was used rather than raw leachate, and the best volumetric ratio was 2%. The following removals were obtained: 97% for the biochemical oxygen demand (BOD5,20), 79% for total suspended solids, 77% for dissolved organic carbon and 84% for soluble chemical oxygen demand. Most of the pretreated leachate SBOM (65%) was removed rather than diluted or adsorbed into the sludge, as confirmed by Fourier transform infrared (FTIR) spectroscopy analyses.


Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2393 ◽  
Author(s):  
Mehmood ◽  
Rehman ◽  
Wang ◽  
Farooq ◽  
Mahmood ◽  
...  

Physicochemical treatment, consisting of a combination of primary settling, coagulation–flocculation-aided clarification (alum, lime and magnesium sulfate as coagulants) and activated carbon adsorption, was employed for the treatment of pulp and paper mill wastewater. Treatability studies were undertaken to assess the feasibility of recycling the effluents from a paper mill. The results of laboratory scale investigation showed that the hydraulic retention time (HRT) of four hours for plain settling was effective to reduce 30% of the pollution load from pulp and board mill wastewater (PBMWW). The chemical secondary treatment reduced turbidity (89%), Chemical Oxygen Demand (84%), total suspended solids (90%) and color (89%) at the mass loading of 3400 mgl-1 of magnesium sulfate (MgSO4), when primary-treated effluent was subsequently treated by the coagulation–flocculation process. The combination of primary settling and lime coagulation (optimum dosage of 1400 mgl-1) resulted in a turbidity removal of 94%, a COD (Chemical Oxygen Demand) reduction of 86%, a Total Suspended Solids (TSS) removal of 93% and color removal of 91.6% at an initial pH of 11. The combination of this primary settling and coagulation–flocculation treatment trial indicated that the pollutant reduction efficiency of alum was better than the other two coagulants (MgSO4, lime), because the plain settling and coagulation–flocculation process with alum (optimum dosage of 1200 mg/L) resulted in a turbidity removal of 98%, COD reduction of 93%, TSS removal of 98% and color removal of 96% at the pH 6.0 with the sludge volume index of 156 mg/L. This chemically-treated water required further treatment with activated carbon in a batch reactor for up to four hours to meet the paper mill water quality standards. Pollutant reductions at the rate of 99.5%, 99.1%, 99.4% and 99.5% were obtained for turbidity, COD, TSS and color, respectively, with the combination of the sedimentation, coagulation–flocculation process and activated carbon adsorption meeting the production process quality standards. The study revealed that a hybrid end-of-pipe physicochemical treatment was effective in reducing the pollutant load of paper mills effluent and meeting the discharging standards.


2020 ◽  
Vol 10 (1) ◽  
pp. 86-95
Author(s):  
Shubhrasekhar Chakraborty ◽  
Pratap Kumar Mohanty ◽  
Jawed Iqbal ◽  
R. Naresh Kumar

Abstract A combined process of sequencing batch reactor (SBR) and electrocoagulation for co-treatment of landfill leachate and municipal wastewater was assessed. SBR was used in the first instance for co-treatment of 20% (v/v) landfill leachate and municipal wastewater mixture. Effluent from SBR was subjected to electrocoagulation for post-treatment, with aluminum as sacrificial anode and stainless steel as cathode. Direct current at a density of 257 A/m2 was applied during the electrocoagulation process. In electrocoagulation, spacing between the two electrodes was varied at 5 and 7 cm to assess its influence on treatment efficiency. SBR was effective to remove 65% chemical oxygen demand (COD), 77% total suspended solids (TSS), 89% ammonia, 80% nitrate, 64% phosphate and post-treatment by electrocoagulation resulted in an overall 98% COD, 98% TSS and 99% ammonia, nitrate and phosphate reduction efficiency with 5 cm of electrode spacing. Respectively, final COD, ammonia and TSS was 37, 1 and 98 mg/L after 150 min of electrocoagulation which met the Indian standards for the discharge of treated wastewater. The results highlight that SBR followed by electrocoagulation as post-treatment can be an effective option for the treatment of landfill leachate and municipal wastewater mixture.


1987 ◽  
Vol 19 (12) ◽  
pp. 265-271
Author(s):  
P. R. Thomas ◽  
H. O. Phelps

The investigation was based on two facultative stabilization ponds initially designed to operate in parallel, and now receive wastewater in excess of their capacities from a fast expanding housing estate in the Caribbean Island of Trinidad. Because of the deterioration of the effluent quality relative to acceptable standards, an attempt was made to upgrade the ponds using water hyacinths at the early stages. However, from the results, it was clear that the introduction of water hyacinths in the test pond did not lead to any substantial improvement in the effluent because of the high loading on the pond. Therefore the ponds were modified to operate in series with surface aerators installed in the first pond. Initially, the effluent quality was monitored in terms of total suspended solids, volatile suspended solids, biochemical oxygen demand, faecal coliform bacteria, pH and dissolved oxygen with aeration in the first pond and no aquatic plants in the second pond. Although there was a significant improvement in the effluent quality, the values remained above the standards. As a result, water hyacinths were introduced in the second pond and the effluent quality monitored together with aeration in the first pond. The effluent quality improved with total suspended solids and biochemical oxygen demand values both as low as 10 mg/l in certain months, but additional treatment was needed to reduce faecal conforms.


Author(s):  
R. Sandhiya ◽  
K. Sumaiya Begum ◽  
D. Charumathi

<p><strong>Objective: </strong>The objectives of the present study were a) to isolate and screen bacteria for dye removal from synthetic solution b) to optimize various variables such as pH, static/shaking and initial dye concentration on degradation of triphenyl methane dyes namely basic violet 3 and basic green 4 by isolated <em>Staphylococcus aureus</em> c) to analyse enzymes involved in the biodegradation of triphenylmethane dyes d) to treat real leather dyeing wastewater with newly isolated strain of <em>Staphylococcus aureus </em>e) to characterize untreated and treated leather dyeing wastewater f) to study the effects of real and treated effluent on plants and <em>Rhizobium</em>.<strong></strong></p><p><strong>Methods: </strong>Isolation of bacteria from sludge was carried out by spread plate method and the bacteria was identified by morphological and biochemical characterization. The isolated bacterium was screened for dye decolorization potential of triphenylmethane dyes basic violet 3 and basic green 4 The effects of parameters were studied by varying pH (from 3 to 9), temperature (from 15-45 °C), and initial dye concentration (from 10-500 mg/l). The enzyme involved in biodegradation was studied in intracellular extract. Real leather dyeing wastewater was treated with the bacteria and characterized. The treated wastewater was tested on plants and <em>Rhizobium </em>for toxicity. <strong></strong></p><p><strong>Results: </strong>Dye decolorization potential of bacteria <em>Staphylococcus aureus</em> isolated from wastewater for leather dyes basic violet 3 and basic green 4 were evaluated. Dye decolorization using bacteria was found to be dependent on physicochemical parameters (shaking, pH and initial dye concentration). Enzymes NADH-DCIP reductase and MG reductase were found to play dominant role during biodegradation of synthetic dyes. Application oriented studies using growing bacteria in pure cultures were carried out with leather dyeing wastewater collected from DKS prime tanners. Analysis of raw leather dyeing wastewater showed high pollution load in terms of color, Total solids, Total suspended solids, Total dissolved solids and Biological oxygen demand whereas the leather dyeing wastewater treated with pure culture of <em>Staphylococcus aureus</em> showed considerable decrease in Total solids, Total suspended solids, Total dissolved solids and Biological oxygen demand values which were within the permissible limits. Phytotoxicity and microbial toxicity studies confirmed the non-toxic nature of treated leather dyeing wastewater. <strong></strong></p><p><strong>Conclusion: </strong>Our study proved that <em>Staphylococcus aureus</em> can serve as a potential remediation agent for the treatment of leather dyeing wastewater.</p>


2014 ◽  
Vol 34 (4) ◽  
pp. 770-779 ◽  
Author(s):  
Fábio Orssatto ◽  
Marcio A. Vilas Boas ◽  
Ricardo Nagamine ◽  
Miguel A. Uribe-Opazo

The current study used statistical methods of quality control to evaluate the performance of a sewage treatment station. The concerned station is located in Cascavel city, Paraná State. The evaluated parameters were hydrogenionic potential, settleable solids, total suspended solids, chemical oxygen demand and biochemical oxygen demand in five days. Statistical analysis was performed through Shewhart control charts and process capability ratio. According to Shewhart charts, only the BOD(5.20) variable was under statistical control. Through capability ratios, we observed that except for pH the sewage treatment station is not capable to produce effluents under characteristics that fulfill specifications or standard launching required by environmental legislation.


2020 ◽  
Vol 9 (6) ◽  
pp. e183963748
Author(s):  
Rafael Souza Leopoldino Nascimento ◽  
Ludymyla Marcelle Lima Silva ◽  
Lucas Periard ◽  
Anibal da Fonseca Santiago

The technology of microalgae photobioreactors and illuminated by LEDs has been widely studied for the treatment of wastewater. However, sunlight is a free resource and should be taken advantage of. But the question remains whether photobioreactors illuminated by natural (sunlight) light in combination with artificial light can have greater operational stability or greater performance when compared to systems illuminated only by artificial light. In this context, continuous flow photobioreactors illuminated by Light Emitting Diodes (LEDs) combined, or not, with sunlight were operated and had their performance evaluated. The variables analyzed were pH, OD, chemical oxygen demand (COD), chlorophyll - a and total suspended solids. The photobioreactors were effective for removing organic matter, with 75 ± 15% in the photobioreactor illuminated by LED and 65 ± 10% in the photobioreactor illuminated by sunlight and LED. The results showed that the use of combined lighting favors the production of dissolved oxygen and ensures greater operational stability in the removal of carbonaceous organic matter.


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