Effluent Removal Research Articles

Lab Scale Study on Synergistic Disinfection of WWTPS Secondary Effluent by Ultrasonic and Ozone

Secondary effluent from WWTPS still contains a large number of microorganisms, therefore, disinfection is essential. There are many disadvantages in using traditional disinfection methods, so the combination of disinfection techniques is a new research direction. Ozone combined with ultrasound is one of them. In this experiment, the inactivation of the total coli forms, color removal and UV254 removal of secondary effluent by a combination of ultrasonic (frequency20 kHz; power100W) and ozone disinfection was investigated. The results show that the effect of the synergistic action of 30s US and ozone disinfection is superior to the effect of individual ozone disinfection. After 15min synergistic disinfection, the total coli forms inactivation rate is up to 99.9%, simultaneously color removal rate to 80% and UV254 removal rate to 52%. Compared with individual ozone disinfection, reaction time was reduced by 5 min.

Kinetic Study on COD Removal of Palm Oil Refinery Effluent by UV-Fenton

Kinetic study on COD removal from palm oil refinery effluent (PORE) has been studied by using UV-Fenton's reagent. The wastewater was collected from a refinery mill in Penang, Malaysia and treated using batch reactor with UV-lamp. The concentration of H2O2 was 2.125g and ratio of H2O2:FeSO4·7H2O was 15:1. The results show that the reaction of the oxidation of COD in PORE by UV-Fenton's reagent is second order reaction and the reaction rate constant, k is 2.24, 1.92 and 1.60 dm3/mol·min for temperature 24°C, 30°C and 40°C, respectively.

Preparation of Microbial Flocculant and its Preliminary Application on Removal of Ammonia in Tannery Effluent

The removal of ammonia in tannery effluent was studied elementarily with microbial flocculant in the experiment. Though an orthogonal experiment, the microbial flocculant produced the most by Bacillus cereus when 27°C, pH of 8, incubation time of 48h and the initial ammonia concentration of 1g/100mL; and the mass of microbial flocculant was positive correlated with the growth of the Bacillus cereus. After treating the tannery effluent containing ammonia through the microbial flocculant, it was found that the microbial flocculant had the ability to remove ammonia in tannery effluent. By detecting the removal effect of ammonia in tannery effluent at different pH, the removal ratio was higher under slightly alkaline condition with the microbial flocculant. The experiments may contribute to the application of microbial flocculant to ammonia removal in tannery effluent.

Bioremediation Potential of Mixed White Rot Culture of Pleurotus Ostreatus IBL-02 and Coriolus Versicolor IBL-04 for Textile Industry Wastewater

In continuation of our studies on single fungal cultures, this study was aimed to investigate the potential of mixed culture of two indigenous white rot fungi Pleurotus ostreatus IBL-02 and Coriolus versicolor IBL-04 to decolorize and detoxify the dye based textile effluent collected from Sitara Textile Industry (SIT), Faisalabad, Pakistan. Different pHysical and nutritional factors were optimized to enhance the efficiency of mixed culture for SIT effluent color removal. Under optimum conditions, the mixed culture completely decolorized (100%) the effluent in 2 days using glucose and urea as carbon and nitrogen sources, respectively in 30:1 ratio. The mixed culture produced all the three major liginolytic enzymes like lignin peroxidase (LiP), manganase peroxidase (MnP) and lacaase. Mediators of ligninolytic enzymes including varatryl alcohol, ABTS and MnSO4 enhanced effluent decolorization showing variable effects on LiP, MnP and laccase activities. Analysis of the treated and untreated SIT effluent showed that fungal treatment significantly reduced the Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) of the effluent.

Pilot Scale Study on Biological Nutrient Removal and Membrane Fouling Alleviation in Combined Membrane Bioreactor for Municipal Wastewater Treatment

To solve the problem of eutrophication in receiving water, a novel Membrane Bioreactor (MBR) with combined configuration was designed for municipal wastewater treatment and reclamation. By dividing bioreactor into three zones, the combined MBR operated under anoxic, anaerobic and aerobic conditions. It provided optimum conditions for nitrification, denitrifying and phosphate accumulating bacterial growth which resulted in high biological nutrient removal rate directly. The operational performance of combined MBR pilot plant showed that it exhibited high nutrient removal rate on Chemical oxygen demand (CODcr), total nitrogen (TN) and total phosphorus (TP). The mean value of effluent CODcr, TN and TP removal rate was 90.63%, 63.05% and 60.51% respectively during 180 days of operation. In order to obtain stable membrane flux, the combined MBR packed with fibrous bio-film carrier and added diatomite. Furthermore, it could alleviate membrane fouling effectively. As a result, the combined MBR improved effluent water quality significantly and alleviated membrane fouling remarkably.

Hydrogen gas production from acid hydrolyzed wheat starch by combined dark and photo-fermentation with periodic feeding

Hydrogen gas production from acid hydrolyzed waste wheat starch by combined dark and photo-fermentation was investigated in continuous mode with periodic feeding and effluent removal. A mixture of heat treated anaerobic sludge and Rhodobacter sphaeroides (NRRL-B 1727) were used as the seed culture for dark and light fermentations, respectively with biomass ratio of Rhodobacter/sludge = 3. Hydraulic residence time (HRT) was changed between 1 and 8 days by adjusting the feeding periods. Ground waste wheat was acid hydrolyzed at pH = 3 and 121 °C for 30 min using an autoclave and the resulting sugar solution was used as the substrate for combined fermentation after pH adjustment and nutrient addition. The highest daily hydrogen gas production (41 ml d −1), hydrogen yield (470 ml g −1 total sugar = 3.4 mol H 2 mol −1glucose), volumetric and specific hydrogen production rates were obtained at the HRT of 8 days. The highest biomass and the lowest total volatile fatty acids (TVFA) concentrations were also realized at HRT = 8 days indicating VFA fermentation by Rhodobacter sp. at high HRTs. The lowest total sugar loading rate of 0.625 g L −1 d −1 resulted in the highest hydrogen yield and formation rate. Hydrogen gas production by combined fermentation with periodic feeding was proven to be an effective method resulting in high hydrogen yields at long HRTs.

Removal of Trace Cd2+ Using Continuous Multistage Ion Foam Fractionation: Part II—The Effects of Operational Parameters

A multistage ion foam fractionation column with bubble-cap trays was employed to study the removal of cadmium ions from simulated wastewater having low Cd concentrations (10–30 mg/L), examining the effects of foam height, air flow rate, feed flow rate, and feed Cd concentration. Sodium dodecyl sulfate (SDS) was used to generate foam in this study. An increase in foam height, which reduces liquid hold-up in the generated foam, resulted in the enhancement of the enrichment ratios of both SDS and Cd while the removal and residual factor of Cd showed insignificant change. An increase in air flow rate increased the foam generation rate, foamate volumetric ratio, and the removal efficiency of Cd but decreased the enrichment ratios of both Cd and SDS. The separation factors of both Cd and SDS decreased with increasing feed flow rate, which is mainly attributable to both the effects of the enhancement of foamate volumetric ratio and the increases in both SDS and Cd input rates. An increase in feed Cd concentration was found to increase Cd effluent concentration and SDS removal but to decrease the enrichment ratios of both Cd and SDS because of the increasing liquid entrainment in the produced foam.

Nutrient removal of effluent from quail farm through cultivation of Wolffia arrhiza

The objective of this work was to study the nutrient removal using the Wolffia arrhiza during the treatment of laying quails farm effluent. The relationship between W. arrhiza biomass and treatment time, the change in water qualities, and nitrogen-balance (N-balance) were evaluated. The results showed that a biomass of 12.0 g of W. arrhiza per liter of effluent and a treatment period of 30 days were found to provide the best conditions for W. arrhiza’s growth and the quality of the treated effluent in terms of biological oxygen demand, suspended solids, total phosphorus, nitrate, total ammonia nitrogen and total Kjeldahl nitrogen. The pH and salinity were similar for each level of biomass. The W. arrhiza biomasses of 4.00–12.0 g/l of effluent were suitable for W. arrhiza survival over time. Since W. arrhiza can fix N in the atmosphere, it can grow very well in effluent containing a low level of N.

Dark fermentative bio-hydrogen production from waste wheat starch using co-culture with periodic feeding: Effects of substrate loading rate

Dark fermentation experiments were performed for bio-hydrogen production from ground wheat starch solution (10 ± 1 g l −1) using periodic feeding and effluent removal. A mixed culture of Clostridium butyricum-NRRL 1024 and Clostridium pasteurianum-NRRL B-598 were used with an initial biomass ratio of 1/1.Effects of wheat starch loading rate on the rate and yield of bio-hydrogen formation were investigated. Substrate loading rate was varied between 0.54 and 5.52 g d −1 (HRT = 6–60 h). The highest hydrogen formation rate (280 ml d −1), volumetric hydrogen formation rate (1857 ml H 2 l −1 d −1) and volatile fatty acids (VFAs) concentration were obtained with a substrate loading rate of 5.52 g d −1 (HRT = 6 h). The highest hydrogen yield (109 ml H 2 g TS −1) was obtained with a substrate loading rate of 1.38 g d −1.

Photo-fermentative hydrogen gas production from dark fermentation effluent of acid hydrolyzed wheat starch with periodic feeding

Hydrogen gas production by photo-fermentation of dark fermentation effluent of acid hydrolyzed wheat starch was investigated at different hydraulic residence times (HRT = 1–10 days). Pure Rhodobacter sphaeroides (NRRL B-1727) culture was used in continuous photo-fermentation by periodic feeding and effluent removal. The highest daily hydrogen gas production (85 ml d −1) was obtained at HRT = 4 days (96 h) while the highest hydrogen yield (1200 ml H 2 g −1 TVFA) was realized at HRT = 196 h. Specific and volumetric hydrogen formation rates were also the highest at HRT = 96 h. Steady-state biomass concentrations and biomass yields increased with increasing HRT. TVFA loading rates of 0.32 g L −1 d −1 and 0.51 g L −1 d −1 resulted in the highest hydrogen yield and formation rate, respectively. Hydrogen gas yield obtained in this study compares favorably with the relevant literature reports probably due to operation by periodic feeding and effluent removal.

Photoeletrolytic system applied to remazol red brilliant degradation

Toxicity tests using Sacharomycces cerevisiae were made with simulated textile effluents containing reactive dye (remazol red brilliant) treated by photoeletrolytic process, varying treatment time and applied current. The treatment incorporated an electrolytic reactor with rectangular titanium anode coated with 70% TiO(2)/30% RuO(2) cathode and a rectangular stainless steel coupled with another photolytic reactor containing a high power UV lamp. The treatment system was used in batch recirculation, in other words, the simulated effluent was driven by the system through a helical pump. It was observed that the higher the value of current applied, the longer the treatment has greater color removal of textile effluent and higher mortality of S. cerevisiae, killing up to 100% of the cells at the end of the treatment. With a lower current applied and having the treatment time of 5 minutes, the effluent showed a color removal of 97% and a lower mortality of S. cerevisiae than the effluent simulated without any treatment.

Different depth intermittent sand filters for laboratory treatment of synthetic wastewater with concentrations close to measured septic tank effluent

The objective of this study was to apply hydraulic and chemical oxygen demand (COD) loading rates at the upper limits of the design criteria for buried sand filters to test the sand filter depth design criteria. Over a 274-day study duration, synthetic effluent with a strength of domestic wastewater was intermittently dosed onto two sand filters of 0.2 m diameter, with depths of 0.3 and 0.4 m. Hydraulic and organic carbon loading rates of 105 L m−2 d−1 and 40 g COD m−2 d−1, respectively, were applied to the filters. The filters did not clog and had good effluent removal capabilities for 274 and 190 days, respectively. However, the 0.3 m-deep filter did experience a reduced performance towards the end of the study period. In the 0.3 and 0.4 m-deep filters, the effluent COD and SS concentrations were less than 86 and 31 mg L−1, respectively, and nitrification was nearly complete in both these columns. Ortho-phosphorus (PO4-P) removal in fine sand and laterite ‘upflow’ filters, receiving effluent from the 0.3 m-deep filter, was 10% and 44%, respectively

Photocatalytic Degradation of Eriochrome Black Dye in a Rotating Corrugated Drum Photocatalytic Reactor

Advanced oxidation processes have been investigated as a viable means of treatment for the degradation and removal of dye-containing effluents. In this work, the degradation of an azo dye, Eriochrome black, was studied using a novel photocatalytic reactor in which TiO2 is immobilized on a rotating corrugated drum. The degradation of the dye via the photocatalytic method was confirmed, and degradation rates were compared using different drum designs. Catalyst deactivation was observed, and this process of irreversibility was found to increase with increasing initial dye concentration in the water. A Langmuir-Hinshelwood kinetic analysis was applied, and it was found to agree well with the data in the initial parts of the reaction but diverged with increasing time. The discrepancy was thought to be due to the presence of unquantified reaction intermediates which may only be broken down slowly by the photocatalytic process.

Morphology and photocatalysis of mesoporous titania thin films annealed in different atmosphere for degradation of methyl orange

The effect of different annealing atmosphere on the morphology and photocatalytic activity of mesoporous TiO2 thin films by dip-coating technique is investigated. The annealing temperature and atmosphere causes significant change of the morphology, thermal stability, photoluminescence, and photocatalytic properties of mesoporous TiO2 films. As-prepared mesoporous thin films have an amorphous structure that is transformed to crystalline TiO2 with well-maintained mesoporous structure at 450°C in various annealing atmosphere except that the mesoporous structure is fully destroyed for films annealed in air. Films annealed in N2 show the enhanced UV photodegradation of methyl orange (MO) resulting from the enhanced crystallinity in these films evidenced by XRD and Raman spectra. These findings can be used to tailor the structure and morphology of mesoporous TiO2 films and thus improve their photocatalytic activity for efficient removal of dye effluents in wastewater.

Use of Ferrites Encapsulated with Titanium Dioxide for Photodegradation of Azo Dyes and Color Removal of Textile Effluents

Abstract This article presents results on the synthesis, characterization, and application of ferrites encapsulated by titanium dioxide as a catalyst for the photodegradation of azo dyes and color removal of textile effluents. X-ray diffraction and scanning electron microscopy (SEM)/energy dispersive systems (EDS) results showed that encapsulation was effective, yielding a nanocomposite with a magnetic core and photoactive surface. Photocatalytic tests carried out with azo dye blue HFRL and with textile effluents showed that in the presence of encapsulated ferrites, color removal was enhanced with both low- and high-energy lamps. Photocatalysis of textile effluent led to the removal of anionic surfactants but did not result in chemical oxygen demand removal; nevertheless, it enhanced the aerobic biodegradability of the textile effluent, mainly when ultraviolet light was used. Mass spectrometry data showed that chemical profiles of intermediates accumulated in solution after photocatalysis depended on the ...

Dark fermentation of acid hydrolyzed ground wheat starch for bio-hydrogen production by periodic feeding and effluent removal

Dark fermentation of acid hydrolyzed ground wheat starch for bio-hydrogen production by periodic feeding and effluent removal was investigated at different feeding intervals. Ground wheat was acid hydrolyzed at pH = 3 and T = 121 °C for 30 min using an autoclave. The resulting sugar solution was subjected to dark fermentation with periodic feeding and effluent removal. The feed solution contained 9 ± 0.5 g L −1 total sugar supplemented with some nutrients. Depending on the feeding intervals hydraulic residence time (HRT) was varied between 6 and 60 h. Steady-state daily hydrogen production increased with decreasing HRT. The highest daily hydrogen production (305 ml d −1) and volumetric hydrogen production rate (1220 ml H 2 L −1 d −1) were obtained at HRT of 6 h. Hydrogen yield (130 ml H 2 g −1 total sugar) reached the highest level at HRT = 24 h. Effluent total sugar concentration decreased, biomass concentration and yield increased with increasing HRT indicating more effective sugar fermentation at high HRTs. Dark fermentation end product profile shifted from acetic to butyric acid with increasing HRT. High acetic/butyric acid ratio obtained at low HRTs resulted in high hydrogen yields.

Bio-hydrogen production by photo-fermentation of dark fermentation effluent with intermittent feeding and effluent removal

Pure culture of Rhodobacter sphaeroides (NRRL- B1727) was used for continuous photo-fermentation of volatile fatty acids (VFA) present in the dark fermentation effluent of ground wheat starch. The feed contained 1950 ± 50 mg L −1 total VFA with some nutrient supplementation. Hydraulic residence time (HRT) was varied between 24 and 120 hours. The highest steady-state daily hydrogen production (55 ml d −1) and hydrogen yield (185 ml H 2 g −1 VFA) were obtained at HRT = 72 hours (3 days). Biomass concentration increased with increasing HRT. Volumetric and specific hydrogen formation rates were also maximum at HRT = 72 h. High extent of TVFA fermentation at HRT = 72 h resulted in high hydrogen gas production.

Dissolved Organic Nitrogen Characterization and Bioavailability in Wastewater Effluents

This project addresses the dissolved organic nitrogen (DON) content in the effluents of different wastewater treatment plants (WWTPs). In this report, information is presented on the occurrence and levels of DON in WWTP effluents and its bioavailability. The information presented was generated by a survey of existing data from full scale plants achieving TN removal, direct sampling and monitoring of effluents from selected plants, and laboratory investigations on DON production in biological processes of WWTPs and its bioavailability to algae and bacteria. The results showed that there is a wide variation in effluent DON at different plants, ranging from non-detectable levels to as high as 2.5 mg N/L. The DON fraction of the effluent TN increases with decrease in effluent TN values, and could be as high as 85% of effluent TN. Size fractionation of effluent organic nitrogen (ON) fraction passing through a 1.2 μm filter showed that a significant colloidal fraction of ON exists between 0.1 and 1.2 μm particle size range in some plants. A fraction of the effluent DON is readily bioavailable to algae and bacteria in laboratory bioassays, and the presence of both algae and bacteria species in the bioassay increases the bioavailable DON fraction. This title belongs to WERF Research Report Series . ISBN: 9781843393542 (eBook)

Colour diminution and COD reduction in treatment of coloured effluent by Electrocoagulation

This work experimentally investigates the colour and Chemical Oxygen Demand (COD) removal of effluents containing: Trypan Blue (TB); Orange G (OG) dye using the two most common electrode materials – Mild Steel (MS) and Aluminium (Al). Effects of the time of electrotreatment, solution pH, electrode material, current density and initial dye concentration on decolourisation and COD reduction are reported. MS electrodes show better colour removal efficiency event at lower cell current efficiency compared with Al electrodes and are able to achieve up to 90–98% removal in less than 60 min. Removal efficiency is higher in the case of TB compared with OG irrespective of electrode material due to higher electrostatic attraction between TB molecules and metal hydroxide sludge. Higher current density enhances colour removal even though pH elevation (approaching close to zero point charge) rate is higher. COD reduction is found to be about 10-20% lower than colour diminution measured spectrophotometrically suggesting different mechanisms of dye removal involved during EC.

Electrocoagulation method for colour removal in tea effluent: a case study of Chemomi tea factory in rift valley, Kenya

A simple and efficient electrochemical method that utilizes two steel electrodes and is capable of reducing the colour of tea effluent prior to its discharge into the river system has been developed. The effects of potential difference, inter-electrode distance, surface area of electrodes to effluent volume ratio (S/V), effluent pH, temperature and effluent dilution on power consumption, were investigated. This method was effective at apotential difference of 24 volts, inter-electrode distance of 5 mm, S/V of 18.2 m2/m3 and effluent pH of 6. Effluent dilution led to increase in power consumption while raising temperatures led to a reduction in powerconsumption. Electrochemical method reduced COD, BOD and electrical conductivity by 96.6 %, 84.0 % and 31.5 % respectively but increased pH by 10.32 %. The final pH, EC, COD and BOD values were below KBSmaximum contaminant levels. The proposed mechanism in colour removal process was phenol coupling. Phenolic tea colour pigments were oxidized by electrons from ionization of iron to form keto radicals, which polymerized to form a long chain polymer. The polymer was electro-floated to the surface by hydrogen gas generated from the reduction of water and oxidation of theaflavins.