scholarly journals Turbidity and Chemical Oxygen Demand Reduction from Pig Slurry through a Coagulation Flocculation Process

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2158
Author(s):  
Oumaima El bied ◽  
Mathieu Kessler ◽  
Martire Angélica Terrero ◽  
Taoufiq Fechtali ◽  
Angel Faz Cano ◽  
...  

Pig slurry is considered a high-risk effluent that causes several environmental problems if it is not adequately managed and treated. White Iberian pig farms in the southeast of Spain treat their slurry in situ using separation, double filtration, decantation, and constructed wetland treatments. However, the pretreatment process does not successfully reduce solids, which leads to clogging in the constructed wetlands (CWs). The main objective of this research paper is to reduce the turbidity and chemical oxygen demand (COD) from the effluent to make it appropriate for CW treatment. Optimization of the coagulation–flocculation (CF) process using iron chloride and a cationic flocculent DKFLOCC-1598 was investigated by a central composite design method (CCD). The effects of coagulant concentration, pH, and flocculent on the COD and turbidity removal were evaluated. The best results were found using 0.024 mol L−1 iron chloride and 0.164 mL L−1 flocculent at pH 7.5, which reduced COD by 96% and delivered turbidity removal of 97%. Therefore, the results indicate the high efficiency of the treatment method in reducing the COD and suspended solids.

1978 ◽  
Vol 5 (1) ◽  
pp. 83-97 ◽  
Author(s):  
Robert D. Cameron

The use of cheap, locally available peat as a treatment method for landfill leachate was investigated by passing leachate through plexiglass columns filled with an amorphous-granular peat. Preliminary adjustment of pH showed that reducing pH to 4.8 dramatically reduced adsorption. Increasing the pH to 8.4, metal removal was increased owing to filtration of precipitated metals. The best adsorption of metals occurred at the 'natural' pH of 7.1. Manganese was found to be the limiting pollutant. At the 0.05 mg/ℓ maximum acceptable manganese concentration 94% of the total metals were removed, requiring 159 kg of peat per 1000 ℓ of leachate.Resting the peat for 1 month did significantly increase removal capacity.Desorption of some contaminants occurred when water was percolated through the peat. The desorption test effluent was not toxic to fish although iron, lead and COD (chemical oxygen demand) exceeded acceptable values.Chemical pretreatment using lime and ferric chloride achieved significant iron, manganese and calcium removals. Chemical pretreatment followed by peat adsorption offered no advantage other than reducing toxicity to fish.Peat treatment alone was effective in reducing concentrations to a level that was non-toxic to fish.


2018 ◽  
Vol 31 (2) ◽  
pp. 97-107
Author(s):  
Ahmed Hamdani ◽  
Mohammed Mountadar ◽  
Omar Assobhei

In order to study the simultaneous removal of nitrate and organic matter from a dairy effluent containing 670 mg∙L-1 of nitrate (NO3--N) and 5 760 mg∙L-1 of dissolved chemical oxygen demand (CODd), denitrification in a laboratory scale bioreactor consisting of an immersed bacterial bed colonized by an heterotrophic denitrifying flora (HDF) selected for NO3- reduction, COD consumption and adapted to grow on an effluent produced by a dairy industry was investigated. The obtained results indicated that at the optimal conditions of temperature (30°C), pH (7), COD/NO3--N ratio (5), the operation lasted 108h with total reduction of nitrate in 72h, no nitrite accumulation, and 92% of soluble COD removal in 96h. This indicates that the biodenitrification was accompanied with a high efficiency of matter organic removal as an electron donor, and thereby satisfies the applicable standards.


2021 ◽  
Author(s):  
Yong Cheng ◽  
Longjun Xu ◽  
Chenglun Liu ◽  
Zao Jiang ◽  
Qiyuan Zhang ◽  
...  

Abstract In this work, red mud was used as raw material to extract Al and Fe with hydrochloric acid. The high-efficiency polyaluminum iron chloride (PAFC) flocculant was prepared via adjusting the pH of the leaching solution, the molar ratio of aluminum and iron, and the polymerization temperature. The effect of synthesis and flocculation conditions on the flocculation performance of aged landfill leachate was investigated. The results confirmed that the PAFC prepared at the polymerization pH of 2.5, the Al/Fe molar ratio of 8, and the polymerization temperature of 70 °C had the optimum flocculation effect. The flocculation consequences of PAFC and commercial polyaluminum iron chloride flocculant (CPAFC) under different flocculation conditions were compared. The chemical oxygen demand (COD), UV254, chroma and settlement height of PAFC at flocculant concentration of 60 g/L and solution pH of 6 were 72.2%, 79.2%, 82.9% and 9.5 cm (within 90 min), respectively. PAFC has excellent flocculation performance and can be used as a simple, potentially low-cost wastewater treatment agent in industrial applications.


Author(s):  
Sheng Dong ◽  
Lijun Liu ◽  
Yuxiu Zhang ◽  
Fajun Jiang

In the drinking water industry, a common advanced treatment process is comprised of treatment with ozone, followed by biological-activated carbon (O3/BAC). However, the bacterial community formation and succession procedures associated with activated carbon have rarely been reported. In this study, the dynamics of bacterial communities at three different depths were investigated using a pilot-scale O3/BAC filter. The average chemical oxygen demand (CODMn), turbidity removal and dissolved oxygen (DO) consumption rate of the filter were 26.43%, 16.57% and 16.4% during the operation period, respectively. Bacterial communities dominated by proteobacteria and Bacteroidetes attached on activated carbon were determined by polymerase chain reaction-density gradient gel electrophoresis (PCR-DGGE). Principal component analysis (PCA) revealed that the compositions and structures of bacterial communities in different layers clustered after fluctuation. A redundancy analysis (RDA) indicated that Ramlibacter henchirensis was positively correlated to chemical oxygen demand (CODMn) removal and nitrate-N removal, and Georgfuchsia toluolica also showed a positive correlation with CODMn removal. Aquabacterium parvum and Phaeobacterium nitratireducens were positively-correlated with turbidity removal. Pedobacter glucosidilyticus and Pseudomonas sp. were associated with high dissolved oxygen (DO) consumption. These results provide insight into the succession characteristics of the bacterial community of O3/BAC treatment and the interactions of the bacterial community with filter operation performance.


Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1343 ◽  
Author(s):  
Piotr Marcinowski ◽  
Dominika Bury ◽  
Monika Krupa ◽  
Dominika Ścieżyńska ◽  
Prasanth Prabhu ◽  
...  

Wastewater from a cosmetic factory, with an initial total organic carbon (TOC) of 146.4 mg/L, was treated with Fe2O3/Fe0/H2O2, Fe3O4/Fe0/H2O2, light/Fe2O3/Fe0/H2O2, and light/Fe3O4/Fe0/H2O2 processes. The light-supported processes were more effective than the lightless processes. The fastest TOC removal was observed during the first 15 min of the process. Out of the four tested kinetic models, the best fit was obtained for the modified second-order reaction with respect to the TOC value. The best treatment efficiency was obtained for the light/Fe3O4/Fe0/H2O2 process with 250/750 mg/L Fe3O4/Fe0 reagent doses, a 1:1 hydrogen peroxide to Chemical Oxygen Demand (H2O2/COD) mass ratio, and a 120 min process time. These conditions allowed 75.7% TOC removal to a final TOC of 35.52 mg/L and 90.5% total nitrogen removal to a final content of 4.9 mg/L. The five-day Biochemical Oxygen Demand to Chemical Oxygen Demand (BOD5/COD) ratio was increased slightly from 0.124 to 0.161. Application of Head Space Solid-Phase Microextraction Gas Chromatography Mass Spectrometry (HS-SPME-GC-MS) analysis allows for the detection and identification of 23 compounds contained in the raw wastewater. The identified compounds were eliminated during the applied process. The HS-SPME-GC-MS results confirmed the high efficiency of the treatment processes.


2010 ◽  
Vol 64 (5) ◽  
pp. 423-430 ◽  
Author(s):  
Milan Cekerevac ◽  
Ljiljana Nikolic-Bujanovic ◽  
Marko Mirkovic ◽  
Negica Popovic

The oxidative and coagulation efficiency of Na2FeO4 solution, electrochemically generated by trans-passive anodic oxidation of electrical steel in 10M NaOH solution, is confirmed in the process of purification of heavily contaminated wastewater from coal separation plant. The decontamination efficiency is evaluated comparing the values of selected contamination parameters obtained by chemical and biochemical analysis of plant effluent water and water obtained after decontamination with ferrate(VI) solution in relatively simple laboratory procedure. The sample of 450 ml of wastewater is treated in laboratory conditions with 100cm3 solution of 1 mg dm-3 Na2FeO4 in 10M NaOH. The chemical analysis of effluent water after treatment have shown almost 3 times lower permanganate index, about 3 times lower iron content, 1.45 times lower As3+ content, 7.35 times lower ammonia content. Turbidity and chemical oxygen demand (COD) is reduced for more than 5.77and 13.4 times, respectively. The suspended and colloid matter is eliminated from effluent water after treatment with ferrate(VI) solution. Also, biochemical exploration has confirmed high efficiency of ferrate(VI) in organics and microbial elimination showing 7.1 times lower 5-days bio-chemical oxygen demand (BOD5), and total elimination of aerobic and anaerobic bacteria from effluent water. According to standards on quality of industrial wastewater effluents, it may be concluded that ferrate(VI) treatment of wastewater almost completely eliminates excess of dangerous chemicals and pathogen bacteria, with the exemption of arsenic. Thus, ferrate(VI) shows capable performance in treatment of coal separation plant wastewater.


2019 ◽  
Vol 8 (2) ◽  
pp. 5919-5923

(Being produced in vast quantity as one of by-product from cassava starch processing chains, cassava pulp has great potential for energy recovery by harnessing biogas through anaerobic digestion (AD). This study aims to enhance biogas production by comparative investigation in batch mode digestion. 5%TS w/v of cassava pulp mixed with mill effluent were pre-treated with 10 molar potassium hydroxide (KOH), sodium hydroxide (NaOH), and calcium hydroxide (Ca(OH)2) solution for 6 hours contact time. Effects of different alkaline pre-treatment on cassava substrate were assessed in total dissolved solid (TDS), soluble chemical oxygen demand (SCOD), Volatile Fatty Acids to Alkalinity ratio (VFA/TA), and reducing sugars. Daily accumulated biogas yield was taken as final indicator of the effect of different pre-treatment. KOH pre-treatment in pH 11 resulted highest dissolved solid 13.07 mg/L, and improved soluble chemical oxygen demand (SCOD) formation up to 75.61% (480,000 mg/L) than control substrate. The experiment revealed peak biogas production by KOH pre-treated substrate was found at day 6 after digestion executed, and achieved 546 ml. The finding proves out of different pre-treatment method applicable to cassava pulp, KOH pre-treatment could realistically increase biogas yield for cassava mills. Biogas production increased up to 101%, 92%, and 70% using KOH, Ca(OH)2 and NaOH respectively. However, when future provision to the technology for AD system and design is concerned, the choice of highly reactive alkali could lead to complication in the system.


2020 ◽  
Vol 4 (1) ◽  
pp. 9-13
Author(s):  
Fadli Mulyadi ◽  
Yulianti Pratama ◽  
Lina Apriyanti

ABSTRAKLimbah cair laboratorium pegujian kualitas air merupakan buangan limbah yang berasal dari kegiatan pengujian kualitas air di laboratorium. Salah satu limbah cair laboratorium yang mengandung Cr6+ adalah limbah cair dari hasil pengujian COD (Chemical Oxygen Demand) yang berpotensi mencemari lingkungan karena bersifat karsinogenik. Sehingga dilakukan penelitian untuk mengetahui efisiensi penyisihan Cr6+ pada limbah cair melalui proses presipitasi dengan penggunaan bahan yang minimum dan ekonomis serta efisien. Variasi terhadap jenis dan konsentrasi presipitan yang digunakan pada penelitian ini adalah NaOH dan Ca(OH)2 dengan nilai konsentrasi 50% serta variasi pH yaitu 8; 9; 10; 11. Hasil penelitian diperoleh efisiensi penyisihan Cr6+ pada proses presipitasi sebesar 44,93% pada variasi jenis presipitan Ca(OH)2 dengan konsentrasi 50% serta pada kondisi pH 8,23.Kata kunci: Limbah COD, Kromium Heksavalen, Presipitasi, Adsorpsi, Efisiensi Penyisihan, Karbon Aktif GranularABSTRACTLiquid laboratory waste generated from water quality examination activities especially from the COD (Chemical Oxygen Demand) analysis contains Cr6+ which potentially pollute the environment due to its carcinogenic effect. The research aimed to determine the removal efficiency of Cr6+ treated by precipitation with a minimum amount of precipitate and high efficiency. In this research, variations of pH were made at constant NaOH and Ca(OH)2 concentrations of 50% while pH levels were adjusted to be 8; 9; 10; 11, respectively. Results showed that the highest Cr6+ removal of 44,93% was obtained by Ca(OH)2 50% with the pH adjusted at 8,23.Keywords: COD contained wastewater, Hexavalent Chromium, Precipitation, Adsorption, Granular Activated Carbon.


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