Effluent Removal Research Articles

A facile green approach of Fe2O3, Fe2O3 @Ag, Fe2O3 @AC and Fe2O3 @Ag@AC NPs synthesized via Cocos nucifera L for waste water treatment applications

In this current work simple one-pot green synthesis approach was applied for synthesis of Fe2O3, Fe2O3@Ag, Fe2O3@AC and the Fe2O3@Ag@AC Nanocomposites (NCs) using Cocos nucifera L. The Cocos nucifera L extract acts both as reducing agent as well as capping agent. Through XRD of green synthesized samples, it was determined that the material had a cubic structure with a maximum absorption at 373 nm assigned to the band-gap. According to the XRD study, the average grain size was 29–30 nm. As a result of FESEM and TEM analysis, rod-like nanostructures were observed with reductions in size. In comparison with methylene blue dye, the synthesized Fe2O3, Fe2O3@Ag, Fe2O3@AC and the Fe2O3@Ag@AC NCs displayed excellent photocatalytic activity. The reason is that charcoal has an adsorption property and iron oxide has a heavy metal reducing property. These properties of the synthesised nano composite allow it to be used in water treatment facilities, and dye effluent removal systems.

Fabrication of Polysulfone-Surface Functionalized Mesoporous Silica Nanocomposite Membranes for Removal of Heavy Metal Ions from Wastewater.

Membranes are an efficient way to treat emulsified heavy metal-based wastewater, but they generally come with a trade-off between permeability and selectivity. In this research, the amine and sulphonic groups on the inner and outer surface of mesoporous silica nanoparticles (MSNs) were first modified by a chemical approach. Then, MSNs with amine and sulphonic groups were utilized as new inorganic nanofiller to fabricate mixed matrix polysulfone (PSU) nanocomposite membranes using the classical phase inversion approach. The resultant nanoparticles and membranes were characterized by their physico-chemical characteristics as well as determination of pure water permeability along with cadmium and zinc ion removal. Embedding nanoparticles resulted in a significant rise in the water permeability as a result of changes in the surface properties and porosity of the membrane. Furthermore, the efficiency of developed membranes to remove cadmium and zinc was significantly improved by more than 90% due to the presence of functional groups on nanoparticles. The functionalized-MSNs/PSU nanocomposite membrane has the potential to be an effective industrial effluent removal membrane.

Orange peel extract influenced partial transformation of SnO2 to SnO in green 3D-ZnO/SnO2 system for chlorophenol degradation

In recent times, visible light enhancement has become much more considered due to the enlightening properties of nanocomposite systems. This has potential applications for wastewater treatment due to the blemish of toxic organic chemicals from industrial sectors. Therefore, this work is focused on novel 3D ZnO/SnO2 nanocomposites synthesized by the green method (orange peel extracts supported combined chemical processes) utilized for the removal of chlorophenol effluent. The orange peel extract has been incorporated as one of the major components to synthesize an effective nanocomposite. Also, the pure materials were synthesized along with these nanocomposites and tested under various instrumental techniques. The characterized results showed that the composites prepared with orange peel extract exhibited hexagonal 3D ZnO nanospheres with 3D tetragonal structured SnO2 nanocubes. Elemental analysis showed that the partial amount of SnO2 has transformed to SnO due to the reducing ability of orange peel extract. Also, the existing different (Zn2+, Sn4+, and Sn2+) states helped in delaying the transfer of electron-hole recombination to obtain photocatalytic chlorophenol degradation. Further, the prevailing line dislocation can compromise more vacancy and interact with more electrons. The high surface area, least crystallite size, and lower bandgap inspired to enhance the visible light activity. Simultaneously, the pure form of nanomaterial has poor light absorption under visible light. This study achieves the photocatalytic degradation of 77.5% against chlorophenol using a green 3D composite system.

Study on the inhibition of sludge bulking in A2/O coupled system at low temperature by segmented inlet water mode

ABSTRACT This study aimed to propose a segmented influent method to inhibit sludge bulking. The sludge bulking phenomenon was observed in a A2/O coupled system treating municipal wastewater under low temperature (15 ± 0.5)°C. Adopting the segmented inlet water process, the distribution ratio of the inlet flow in the anaerobic zone and the aerobic zone were 2:1 and 1:1, the sludge bulking phenomenon was suppressed. The sludge loading rate (F/M) analysis showed that the F/M of the anaerobic zone with single-point inflow was only 0.15 kg COD·(kg MLSS·d)−1, which was prone to induce sludge bulking. However, the F/M concentration gradient of the system under segmented inlet water conditions was obvious, which could inhibit the sludge bulking caused by low F/M. The effluent removal results showed that the system had high removal rates of COD, NH4 +-N, TN, and TP at a flow distribution ratio of 2:1, with average removal rates of 88.85% ± 2.94%, 91.26% ± 6.68%, 76.60% ± 5.60%, and 96.80% ± 2.17%, respectively. This study confirmed that the segment inlet method inhibited sludge bulking, while the flow distribution ratio of 2:1 also ensured efficient pollutant removal capacity of the system.

Sterculia foetida fruit shell based activated carbon for the effective removal of industrial effluents

In this work, Sterculia foetida fruit shells were used for the preparation of activated carbon and utilized for the removal of industrial effluent methylene blue is described. The carbon materials were prepared by washing the shells with water, dried in sunlight and subjected to heating at 700 ​°C in a muffle furnace to get the carbon material. This is divided into three portions, one is used as pristine and two portions were subjected to physical activation using steam and chemical activation using K2CO3. The impurities were removed by treatment with NaOH (0.1 ​M) and subsequently with HCl (0.1 M). Turbostatic structure was determined by XRD and the specific surface area was determined using BET showed 4, 1017 and 596 ​m2/g as the surface areas. Using these activated carbon materials, we have achieved 93% removal of methylene blue, found in industrial effluents.

Electro-oxidation of fish meal industry wastewater in a stirred batch reactor using a Ti/RuO2 anode

Abstract Fish meal is used as feed for fish, dogs and cats, and in the pharmaceutical industry. Direct electro-oxidation has been used to treat fish meal industry effluent and organic pollutant removal, and was studied in this project. The anode used was titanium coated with ruthenium oxide and the cathode was stainless steel. In addition to organic pollutants, color removal was also studied. The varying parameter was current density, and those used were 10, 20, 27, and 34 mA/cm2. The effects of mechanical agitation and the inter-electrode distance on pollutant removal were also studied. The highest TOC and color removal (both 82%) were achieved at 34 mA/cm2, using mechanical agitation with 1.5 cm electrode spacing. Without agitation, TOC removal efficiency was 72%. The results show that electro-oxidation can be an effective secondary treatment for fish meal industry effluent.

Characterization of a novel micro-pressure double-cycle reactor for low temperature municipal wastewater treatment

ABSTRACT To solve the deterioration of effluent caused by low temperature in urban sewage treatment plant in cold areas, a new type of reactor was proposed, the biochemical environmental and low-temperature operating characteristics of the reactor were studied. Through analysis of flow simulation and dissolved oxygen (DO) distribution when the aeration rate was 0.6 m3/h, it showed that there were many different DO environments in the reactor at the same time, which provided favourable conditions for various biochemical reactions. The operation test showed that the average effluent removal rate of COD, TN, NH4 +-N and TP was 92.53%, 74.57%, 89.61% and 96.04%, respectively. And there were a variety of functional bacteria related to nitrogen and phosphorus removal in the system, most of them with strong adaptability at low temperatures. Among the dominant microorganisms, Flavobacterium and Rhodobacter were related to denitrification, Aeromonas and Thiothrix were related to phosphorous removal. Denitrifying phosphorus removal was the main way of phosphorus removal. Picrust2 results showed that the reactor operated well at low temperature, and the regional difference distribution of nitrification genes further confirmed the existence of functional zones in the reactor. The results showed that the Micro-pressure Double-cycle reactor worked well at low temperature, which provided a new idea and way for the upgrading of urban sewage treatment plants in cold areas.

Application of Box-Behnken design to mineralization and color removal of palm oil mill effluent by electrocoagulation process.

In this study, palm oil mill effluent (POME) was treated using electrocoagulation, whereby the influencing factors including voltage, electrolysis time, and electrolyte amount were optimized to achieve the highest chemical oxygen demand (COD) and color removal efficiencies. Graphite was selected as electrode material due to its performance better compared to aluminum and copper. Response surface methodology (RSM) was carried out for optimization of the electrocoagulation operating parameters. The best model obtained using Box-Behnken design (BBD) were quadratic for COD removal (R2 = 0.9844), color reduction (R2 = 0.9412), and oil and grease removal (R2 = 0.9724). The result from the analysis of variance (ANOVA) was obtained to determine the relationship between factors and treatment efficiencies. The experimental results under optimized conditions such as voltage 14, electrolysis time of 3 h, and electrolyte amount of 13.41 g/L show that the electrocoagulation process effectively reduced the COD (56%), color (65%), and oil and grease (99%) of the POME treatment. Graphical abstract.

Detection of Reserve Oxygen Potential in the Present of Fine Bubbles and its Ammonia Removal for Aquaculture Effluent

The availability of oxygen and the minimum amount of ammonia in the water media are crucial in catfish larvae hatchery performance. The condition with a balanced amount of required oxygen and the presence of ammonia resulting from the feces of striped catfish larvae is essential to maintain the health of the aquaculture media. This study aims to remove ammonia by introducing fine bubbles (FBs) into recirculating aquaculture media and investigating reserved dissolved oxygen inside the bubbles in the media. The water media for the striped catfish larvae hatchery was designed and set up with three containers in a recirculating system. Also, a separate container was utilized as bubble storage connected to FBs generator. The water treatment was conducted in three different scenarios using air and pure oxygen as the FBs generator sources. The generated FBs were investigated in terms of their size and zeta potential concerning the dissolved oxygen (DO). The media’s DO was measured using the titration method and digital DO meter. The difference in DO concentration received from titration and DO meter define as potential reserved oxygen. Furthermore, the removal of synthetic effluent (ammonia, NH4Cl) and effluent in the media with FBs resources were investigated and tested at a different duration of FBs applications. The results showed that bubbles size was 518.5 – 607.6 nm independent of gas resource, either pure oxygen or air. However, the gas resources affected the zeta potential value of suspended bubbles, air (-11.5 to -16.7 mV), and pure oxygen (-21.4 to -25.2 mV). When pure oxygen was used as a gas resource, the media reach the oxygen supersaturation DO condition (25.39 ppm) within 45 minutes with reserve oxygen potential (ROP) of 2.95 ppm. Thus, this condition allowed the synthetic effluent removal of 83.33% and effluent removal of 39.93%. It is emphasized that the ammonia removal due to the presence of reactive oxygen species when the FBs collapsed and the information of ROP due to FBs application is important to preserve the fitness of aquaculture media for catfish larvae hatchery.

Mesocosm- and Field-Scale Evaluation of Lignocellulose- Amended Soil Treatment Areas for Removal of Nitrogen from Wastewater

Non-proprietary N-removal onsite wastewater treatment systems are less costly than proprietary systems, increasing the likelihood of adoption to lower N inputs to receiving waters. We assessed the capacity of non-proprietary lignocellulose-amended soil treatment areas (LCSTAs)—a 45-cm-deep layer of sand above a 45-cm-deep layer of sand and sawdust—to lower the concentration of total N (TN) in septic tank effluent (STE) at mesocosm and field scales. The mesocosm received wastewater for two years and had a median effluent TN concentration of 3.1 mg/L and TN removal of 60–100%, meeting regulatory standards of 19 mg/L or 50% removal. Removal varied inversely with temperature, and was lower below 10 °C. Removal was higher in the mesocosm than in five field sites monitored for 12–42 months. Median effluent TN concentration and removal met the standard in three continuously-occupied homes but not for two seasonally-occupied homes. Sites differed in temporal pattern of TN removal, and in four of five sites TN removal was greater—and effluent TN concentration lower—in the LCSTA than in a control STA containing only sand. The performance of non-proprietary LCSTAs was comparable to that for proprietary systems, suggesting that these may be a viable, more affordable alternative for lowering N inputs to receiving waters.

MXene@Poly(diallyldimethylammonium chloride) Decorated Carbon Cloth for Highly Electrochemically Active Biofilms in Microbial Fuel Cells

AbstractThe anode characteristics are important to the performance of microbial fuel cells (MFCs) due to the influence on biofilm formation and extracellular electron transfer (EET). Herein, MXene was modified by the superhydrophilic cationic polymer poly(diallyldimethylammonium chloride) (PDDA) to prepare MXene@PDDA/carbon cloth (CC) as an anode for MFC. The unique anode combines the advantages of high conductivity, superhydrophilicity and biocompatibility. The anode facilitated the enrichment of electrochemical active bacterium and promoted the efficiency of EET process. MFCs based on MXene@PDDA/CC anodes can produce the remarkable power output and the satisfactory effluent removal efficiency through an external series resistance of 1 kΩ. The device can gain the maximum output voltage of 585 mV and the maximum power density of 811 mW m−2. The efficiencies of methyl orange decolorization and chemical oxygen demand were up to 79 % and 84 % after 12 h, respectively.

Electrocoagulation treatment of shale gas drilling wastewater: Performance and statistical optimization

Shale gas drilling wastewater is a challenging waste stream generated in gas industries. It is a mixture of different organic and inorganic compounds. Treatment of this complex wastewater relies on a suitable technology for the removal of small suspended particles and dissolved elements. This study employed electrocoagulation (EC) as an efficient method for shale gas drilling wastewater pretreatment. The optimum operating conditions for turbidity, TOC, and Ca2+ removal were determined using a response surface methodology (RSM). The chloride (Cl−) removal and residual iron of effluent in the EC process were also tested and evaluated. Based on the analysis of variance (ANOVA), the coefficient of determination (R2) was calculated and found to be above 0.86 for all the responses. The maximum removal efficiencies were found to be around 98.3%, 78.5%, and 56.5% for turbidity, TOC, and Ca2+ removal under the optimum conditions, respectively. In order to treat drilling wastewater by EC process both efficiently and economically, the following operating parameters are recommended: 318 A/m2 for current density, 20 min for reaction time and 4.4 for initial pH. A total operation cost of 0.80 US$/m3 was estimated under these conditions.

Status and needs for online control of tertiary ozone-based water treatment: use of surrogate correlation models for removal of trace organic contaminants

The number of studies dealing with tertiary ozonation to remove trace organic contaminants (TrOCs) in effluents originating from wastewater treatment plants (WWTPs) is increasing due to the need for upgrading the WWTPs overall performance. To follow-up TrOCs removal in real-time during ozone-based treatment, online surrogate measurements are necessary, of which mainly spectroscopic surrogates (i.e. UV–VIS absorbance and fluorescence) are the emerging techniques in literature. This paper summarizes and reflects on the state-of-the-art as retrieved from more than 100 peer-reviewed studies published between January 2007 and December 2020 and dealing with (1) surrogate correlation models for the prediction of TrOCs removal in secondary effluent and (2) control strategies to adjust the ozone dose during (full-scale) operation. Next to the flow and load proportional ozone dosing strategies, controlling the ozone dose solely based on the characteristics of the effluent entering the ozonation unit, also a differential control strategy based on the change in characteristics due to ozonation of the WWTP effluent is highlighted. The latter seems the best option as flow and load proportional ozone dosing do not consider the amount and/or reactivity of the matrix constituents. The presence of organic and inorganic scavengers of ozone and radicals in the effluent matrix has a significant impact on the TrOCs removal efficiency. This effluent quality can differ in time and between WWTPs, hence the surrogate correlation models should be widely applicable. At the end of the review, recommendations are made for future research and implementation of an effective control strategy for (full-scale) applications.

Effect of Calcined Limestone on the Performance of Roughing Filter for Turbidity Removal of Palm Oil Mill Effluent

Abstract Malaysia is considered as a major palm oil producer in the world. Therefore, it is vital to utilize an environmentally friendly and inexpensive method to treat palm oil mill effluent (POME...

Multi-metal effluent removal by Centella asiatica (L) Urban: Prospects in phytoremediation

The search for an efficient plant for simultaneous extraction of ten trace elements from industrial effluent has lead us to Centella asiatica , a native species, known for medicinal properties. After 28-d of trial, it could effectively lower toxic metals such as Cd (14%–54%), Cr (2%–43%), Cu (18%–81%), Pb (35%–90%), Ni (13%–59%) and Zn (20%–81%) from test solutions that comprised of the effluent from a pulp and paper mill that was appropriately diluted with 30% Hoagland’s solution The plant demonstrated favourable attributes such as augmentation of key antioxidant enzymes (SOD, CAT, APX and GPX) for combating oxidative stress. Plants showed improved growth and worked well in the lowest effluent dose (25%, v/v). Scanning electron microscopy along with energy dispersive X-ray microanalysis of the root showed the localization of all the trace elements, Pb (weight %, 11–28) and Cd (weight %, 3.1–6.8) peaks indicated that adsorbed metals predominantly remained in the root at 75% and 100% (v/v) exposures. The phytoremediation trials were validated by bioassays in Clarias batrachus reared in phytoremediated effluents; fish showed lower metal burden, most toxic trace metals were within the safe levels, which was suggestive of the accomplishment of phytoremediation and utilities for bio-monitoring purposes. • Centella asiatica simultaneously extracted 10 trace elements from effluent. • Decrement in the level of trace elements were registered from effluent after trials. • Plants showed improved growth and worked well in the lowest effluent dose. • Plant combated oxidative stress by augmented production of key antioxidant enzymes. • Success of remediation trials were validated by bioassays in a catfish.

Enhanced photocatalytic performance of visible light driven TiO2/g-C3N4 for degradation of diclofenac in aqueous solution

Emerging contaminants such as diclofenac is frequently detected in wastewater treatment plants as they are not specifically designed for the removal of pharmaceutical effluents, which results in poor removal efficiency. Even though photocatalyst has emerged as an excellent alternative, most of the reported photocatalyst portrays fast recombination rate of electron–hole pair and has slow electron mobility. In order to overcome these shortcomings, in the present work, visible light-driven TiO 2/g-C3N4 photocatalyst was synthesized for the photodegradation of diclofenac in aqueous solution. The morphological and optical properties of the photocatalyst were analysed. The photodegradation efficiency was highly improved even at low g-C3N4 loading, indicating the Z-scheme photocatalyst, successfully overcame the electron–hole pair’s fast recombination rate. The photodegradation efficiency was represented as a function of all independent variables, using a second-order quadratic model. Response surface methodology (RSM) was used to optimize the degradation process. A maximum degradation efficiency (93.49%) was achieved at the optimum conditions (irradiation time = 90 min, initial solution pH = 5, initial DCF concentration = 5 ppm and g-C3N4 loading = 0.3g/g TiO 2). The as developed photocatalyst is found to be highly stable as it showed a satisfactory recyclability. The process followed a pseudo-first-order reaction. Photodegradation of diclofenac also resulted in ten intermediates as identified using LCMS analysis.

Solar photocatalytic degradation of ibuprofen with a magnetic catalyst: Effects of parameters, efficiency in effluent, mechanism and toxicity evolution

The environmental-friendly photocatalytic process with a magnetic catalyst CoFe2O4/TiO2 mediated by solar light for ibuprofen (IBP) degradation in pure water, wastewater effluent and artificial seawater was investigated systematically. The study aims to reveal the efficiency, the mechanism and toxicity evolution during IBP degradation. Hydroxyl radicals and photo-hole (h+) were found to contribute to the IBP decay. The presence of SO42- showed no significant effect, while NO3- accelerated the photodegradation, and other anions including HCO3-, Cl-, F-, and Br- showed significant inhibition. The removal efficiency was significantly elevated with the addition of peroxymonosulfate (PMS) or persulfate (PS) ([Oxidant]0:[IBP]0=0.4-4), with reaction rate of 5.3-13.1 and 1.3-2.9 times as high as the control group, respectively. However, the reaction was slowed down with the introduction of H2O2. A mathematic model was employed to describe the effect of ferrate, high concentration or stepwise addition of ferrate was suggested to play a positive role in IBP photodegradation. Thirteen transformation products were identified and five of them were newly reported. The degradation pathways including hydroxylation, the benzene ring opening and the oxidation of carbon were proposed. IBP can be efficiently removed when spiked in wastewater and seawater despite the decreased degradation rate by 41% and 56%, respectively. Compared to the IBP removal, mineralization was relatively lower. The adverse effect of the parent compound IBP to the green algae Chlorella vulgaris was gradually eliminated with the decomposition of IBP. The transformation product C178a which possibly posed toxicity to rotifers Brachionus calyciflorus can also be efficiently removed, indicating that the photocatalysis process is effective in IBP removal, mineralization and toxicity elimination.

COD removal and colour degradation of textile dye effluents by locally isolated microbes

ABSTRACT Textile industry has been rapidly progressing over the years, leading to an increasing volume of water usage that contributes to the large production of textile wastewater. Biological treatment processes have been proven to be the most environmentally friendly, cost-effective and requiring reduced production treatment by-products. In this study, using microbial treatment was applied. Three potential local isolates of micro-organism had been isolated from textile wastewater. The treatment processes were studied under two conditions, namely aerobic and anaerobic. Decolourization of seven commercial textile dyes, namely Crystal Violet 3, Acid Black 1, Basic Blue 8, Acid Blue 147, Congo R, Chrysoiodine R and Yellow 2 G were studied. After seven days of incubation, a significant reduction of 92% for Yellow 2G (Y) and 73.73%for Chrysoiodine R was observed, indicating a high capability of the bacterial isolates indye-degrading activities. Highest chemical oxygen demand (COD) removal was achieved byisolate C3K (93.93%), followed by isolate C3W (90.5%) and isolate C1 (89.173%) in nineincubation days, highlighting the ability of these microbial isolates in removing COD from the individual textile dyes.

Combined treatment with α-amylase and Saccharomyces cerevisiae culture for nutrient removal and biomass production in effluent from rice parboilization

Combined treatment with α-amylase and Saccharomyces cerevisiae culture for nutrient removal and biomass production in effluent from rice parboilization

Microalgae based wastewater treatment: a shifting paradigm for the developing nations

Decreased water quality in freshwater resources due to untreated or partially treated wastewater disposal resulting in eutrophication has led to water scarcity. Hence, the present work was aimed to determine the effectiveness of Chlorella vulgaris for municipal wastewater treatment in terms of various physico-chemical parameters and nutrient removal. Primary treated effluent was collected from a sewage treatment plant as an influent for the study. Parameters analyzed during the lab-scale batch study of 7 hours of detention time were pH, EC, TDS, TSS, TS, COD, phosphate, ammonia, nitrate and DO. Removal efficiency reached 98.32, 97.26 and 84.71% for phosphate, ammonia and COD, respectively, for non-filtered effluents. However, filtered effluent removal efficiency reached 98.53, 98.63 and 89.41% for phosphate, ammonia and COD, respectively. The study revealed that microalgal treatment, if incorporated in conventional wasteater treatment, can be a solution to the limitations of the activated sludge process. It could be a promising technique for low income and developing countries, which could efficiently reduce the effluent concentration to much lesser than the desirable limits in an eco-friendly and cost-effective way. Statement of novelty Municipal wastewater treatment in most developing countries is confined to aerobic secondary treatments, which are costly and are not efficient in removing nutrients from the treated effluents before discharging and leading to the imbalance and eutrophication in the receiving bodies. Hence in this study, an attempt was made to study the effectiveness of Chlorella vulgaris for wastewater treatment at a detention time of 7 hours without any external aeration. The present study revealed that microalgae have efficiently removed organics and nutrients to much lesser than the desirable limit. Thus, if the Chlorella vulgaris is introduced in the wastewater treatment system can reduce the nutrients and organics concentrations without the need for aeration, which can be an energy-saving and cost-effective approach.