Initial Effluent Concentration Research Articles

Two-step polyhydroxybutyrate production from hydrogenic effluent by freshwater microalgae Coelastrella sp. KKU-P1 and Acutodesmus sp. KKU-P2 under mixotrophic cultivation

This study aimed to produce PHB using hydrogenic effluent discharged from the biohydrogen production process with freshwater microalgae including Coelastrella sp. KKU-P1, and Acutodesmus sp. KKU-P2. Batch experiments explored the influence of initial pH and hydrogenic effluent concentration, revealing optimal conditions at 10 % (v/v) effluent concentration and a pH of 6.5 for both KKU-P1 and KKU-P2. Subsequently, medium formulation and photoperiods were optimized to maximize biomass and PHB accumulation. The results showed that the optimal condition for PHB accumulation with KKU-P1 and KKU-P2 was nitrogen phosphorus (NP)-limited Bold's Basal Medium (BBM) under dark conditions. A two-step PHB accumulation in the upscale bioreactor was investigated under optimal conditions. The results showed that KKU-P1 achieved maximum PHB, protein, carbohydrate, and lipid contents of 4.57 %, 29.37 %, 24.76 %, and 13.21 %, respectively, whereas KKU-P2 achieved 6.35 %, 31.53 %, 16.16 %, and 4.77 %, respectively. Based on these findings, it appears that a mixotrophic approach under nutrient-limiting conditions is effective for PHB production in both KKU-P1 and KKU-P2 strains.

Synthesis of a SiO2-MgO composite material derived from yellow phosphorus slag with excellent malachite green adsorption activity

There has been increasing attention devoted to the treatment of wastewater to eliminate organic dyes. Here, a composite material was developed using SiO2 matrix material obtained from yellow phosphorus slag and loaded with MgO, then examined for its ability to absorb the malachite green dye. The influence of a variety of variables, such as time, temperature, pH, and initial simulated effluent concentration, was investigated. These investigations demonstrated that when using this SiO2-MgO adsorbent, a maximum malachite green adsorption rate of 97.72 % was obtained, with precisely 115.64 mg g−1 of dye absorbed. Interestingly, the prepared SiO2-MgO was stable and regenerated successfully, exhibiting good performance throughout the four cycles. The specific surface area and pore size of the developed adsorbent composite material were found to be 352.76 m2 g−1 and 2–10 nm, respectively. Scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analyses revealed that electrostatic adsorption, dipole-dipole H-bonding, ion exchange, and Yoshida H-bonding interactions were among the mechanisms used by this SiO2-MgO composite to adsorb malachite green. Importantly, this adsorbent can be simply and efficiently produced, making it well-suited to lowering MgO utilization and raising SiO2 adsorption efficacy while allowing for greater yellow phosphorus slag utilization and the establishment of a novel solid waste treatment approach.

Adsorption Isotherms for Removal of Heavy Metal Ions (Copper and Nickel) from Aqueous Solutions in Single and Binary Adsorption Processes

This study deals with the removal of single and binary heavy metals, which cause great problems in terms of the environment and human health, through very low cost, economical and easily obtainable materials. The purpose of this study is to investigate the single- and binary uptake of Copper (II) and Nickel (II) ions onto the Sepiolite in the terms of a thermodynamic perspective. For mono-component systems, the initial effluent concentration, mixing speed and temperature have been studied as a function of time to determine the conditions where the adsorbents show a great deal of affinity towards the Cu (II) and Ni (II) ions in aqueous solutions. Before the metal adsorption experiments, the Physical properties of Sepiolite were identified via Brunauer–Emmett–Teller (BET) analysis. The single metal ion uptake studies were performed at 20, 25, 30, and 35 °C. At equilibrium, the sorption data were individually shown to correlate well with the non-competitive Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich isotherms. Among the applied isotherm models, the one-component sorption values do fit the Langmuir isotherm best. The simultaneous and competitive uptake of Cu (II) and Ni (II) was assessed by the extended Langmuir and Freundlich isotherms. Both adsorption equations complied with the two-component sorption data perfectly. Single- and binary-sorption results unclose that the effect of Sepiolite to Cu (II) is greater than that of Sepiolite to Ni (II).

Kinetics, process design and implementation of zwitterionic adsorbent coating for dipolar dyes removal in wastewater treatment industry

Kinetic, thermodynamics and process design of the adsorption of dipolar dye molecules, namely Brilliant green (BG) and Naphthalene Blue 12B (NB12B), from aqueous solution using a zwitterionic adsorbent coating (ZwitAd) were investigated. This zwitterionic adsorbent coating was synthesized by a facile technique, which implied only 3 main chemicals: acrylic polymer emulsion (binder), bentonite (fillers) and EPIDMA (cationic polyelectrolyte). The scale-up of this formulation was proved showing that this coating adsorbent is viable to be adopted in a large-scale production. This novel adsorbent was synthesized in a coating form to obtain a feasible and practical application for the adsorption of both cationic and anionic dyes from wastewaters. Besides, this new adsorbent could be easily separated from the system without applying extra processing methods such as filtration or centrifugation. Adsorption studies showed that Freundlich model described satisfactorily the BG adsorption, whereas the NB12B adsorption was fitted with Langmuir isotherm. A single stage process was designed and the corresponding mathematical formulations was developed using the best adsorption models. Process design was performed to optimize the adsorbent amount for achieving a specific target of given initial effluent concentration and volume of treated wastewater. This optimization contributed to minimize the capital investment cost in order to satisfy a standard defined for the dye removal. Different alternatives for the application of this novel adsorbent in an industrial facility have been described and discussed. This study contributes with new findings to improve the implementation of novel adsorbents for water treatment and purification at industrial scale.

Performance evaluation of coconut shell originated activated carbon as an adsorbent on the paint factory effluent treatment

The current study was aimed to evaluate the ability of the activated carbon prepared from coconut shell in the decolorization of paint factory effluent (PFE). The studies were performed in the fixed bed adsorption column by optimizing the design variables viz., initial effluent concentration, bed height and low rate. The experimental observations were used to make breakthrough curves and were validated using Adams – Bohart model and Yoon-Nelson model. The results recommended that the encapsulated activated carbon of coconut shell origin showcased its capacity to perform in the process of paint factory effluents decolorization as an adsorbent.

Electrocatalytic activity survey of some cathode materials for the reduction of nitrites and nitrates in aqueous solution

The electrochemical techniques are the subject of increasing interest on the environmental remediation methods thanks to their efficiency and their selectivity. It was classified among the cleanest methods because it does not produce sludge and undesirable intermediate byproducts. For these reasons, we have chosen this technology for the reduction of nitrites and nitrates ions from aqueous solutions. The objective of our study is the comparison of several cathodes materials performances, in order to promote an optimal electro-reduction of these ions. Indeed, we have used the copper, graphite, stainless steel and zinc as cathodes; among them, we have selected the most efficient on which we have optimized the operational conditions. The results suggested that the copper cathode was the most efficient for the reduction of both tested ions compared to the other tested materials. Therefore, the optimization of operational conditions allows us to fixed them at: scan rate=50mV/s, initial effluent concentration=100 mg/L, pH=7 and potential range of the cyclic voltammetry scanning of [-1,+1]V/SCE for both ions. Under these optimal parameters, the reduction yield after 45min was important that can achieve 96.5% and 99% for nitrites and nitrates respectively.

Effective Electro-Fenton Treatment for a Real Textile Effluent: A Case Study

In this study, a real textile effluent (RTE) was treated by the electro-Fenton method in a parallel plate reactor. A carbon fiber cathode and a stainless-steel mesh anode were used as electrodes. The effluent was characterized, and dilute solutions were prepared with initial chemical oxygen demand (COD) concentrations of 50, 100, 200, 250, and 300 ppm. The prepared effluents were degraded for 180 min, at an applied voltage of 1.8 V and a current density of 0.45 mAcm−2. Reductions of more than 85 % of the initial color and 55 % of the COD were achieved. The energy consumption was 7 kW h kgCOD−1 removed. The RTE degradation followed pseudo-first-order kinetics, and its rate constants ranged from 0.01 to 0.02 min−1. It was observed that the degradation rate decreased as the initial effluent concentration increased.Based on the kinetic results, a methodology was developed to predict the effluent degradation. For each kinetic equation, the empirical constant (a) and the rate constant (k) were determined. Mathematical models were formulated for a and k, relative to their respective CODi concentrations, with a correlation coefficient greater than 0.95 in both cases. The theoretical values of at and kt for the working concentrations were calculated using the formulated mathematical models. The theoretical parameters were substituted into the first-order kinetic equation, allowing the simulation of the RTE degradation. The degradation behavior was simulated for each of the five concentrations studied, and the results compared with the experimental results. The theoretical and experimental values showed a high degree of adjustment, demonstrating that the proposed methodology was successful in predicting the degradation of the textile effluent.

Enhanced treatment of landfill leachate wastewater using sono(US)-ozone(O3)–electrocoagulation(EC) process: role of process parameters on color, COD and electrical energy consumption

The combination of advanced oxidation processes (AOPs) and electrochemical process is gaining growing popularity for use in wastewater treatment. The present work explores for the first time, treatment of leachate wastewater from landfill waste using a combination of sonication (US), ozonation (O3) and electrocoagulation (EC) process expressed by % color removal, % Chemical Oxygen Demand (COD) removal and its associated electrical energy consumption. The results revealed that, the combined process (US/O3/EC) is highly successful in the treatment of leachate wastewater from landfill in terms of % color removal (100 %) and % COD removal (97.50 %) with low electrical energy consumption (8kWhr/m3) than the other hybrid and single process such as O3/EC, US/EC, US/O3 and EC, O3, US. The influence of different process parameters such as electrolyte concentration (1.50–7.50 g/L), current density (1.25–7.50 A/dm2), initial effluent pH (2–11), COD concentration (2000–6000 ppm), O3 production (0.75–3.75 g/hr) and sonication power (20–100 Watts) were studied on the efficiency of pollutant removal evaluated by reduction of % color and % COD and electrical energy consumption using hybrid US/O3/EC process. Overall, the analysis clearly showed that the approaches to integrated treatment technologies could synergistically remove the pollutant from the wastewater.

Dissolution-Desorption Dynamics of Strontium During Elution Following Evaporation: pH and Ionic Strength Effects

Radioactive strontium-90 (90Sr2+) is a fission byproduct of uranium and plutonium production, and therefore understanding its environmental fate is of particular importance for predicting the evolution of long-term risk from historical releases. The nonradioactive strontium cation, Sr2+, is a chemical analog for 90Sr2+ that is often used in studies designed to understand the environmental behaviors of 90Sr2+. The focus of this work was on understanding the dynamics of remobilization of strontium following evaporation to dryness in porous media. Evaporation is ubiquitous in the unsaturated zone, and has the potential to significantly impact the dynamics of transport by driving adsorption or precipitation on solid surfaces. For this work, a series of transport experiments were conducted examining the behavior of strontium over a range of pH values, ionic strengths, and concentrations. Saturated transport experiments were conducted, followed by experiments designed to examine the release and transport following evaporation to dryness. Results show increasing saturated retardation with increasing pH, decreasing ionic strength, and decreasing concentration, with the concentration exhibiting the strongest effect. Breakthrough curves at low concentrations were also found to be consistent with significant rate-limited desorption. Remobilization elution curves measured following evaporation to dryness exhibited the high initial effluent concentrations, exceeding the influent strontium concentration, most likely caused by the initial dissolution and accumulation of strontium by the advancing solution. Concentrations at later times were found to be largely consistent with the dynamics of saturated transport for the systems studied.

INFLUENCE OF POULTRY PROCESSING ENTERPRISSE WASTE WATER COMPOSITION ON A RELEVANT DOSE OF ALUMINI POLYOXYCHLORIDE COAGULANT

Wastewater from food processing enterprises are highly polluted. These include pollution of both organic origin and mineral inclusions and detergents. This fact necessitates their preliminary treatment before discharge to biological treatment plants. Most enterprises in the industry use reagent pressure flotation for cleaning.One of the most important aspects of high cleaning efficiency is the correct selection of reagents for treatment. However, due to the high heterogeneity of the wastewater of various enterprises, this task is becoming a quit difficult. So, the wrong selection of the coagulant and its dose can lead to the installation of inappropriate equipment at the enterprise. At the same time, the equipment of a reagent farm can be either insufficient productivity or overstated performance. Both of that will not allow to achieve the required treatment effect and will entail the discharge of untreated sewage into the water reservation.There are 6 operating enterprises which specializing in the production of poultry meat are considered in this paper. Considered enterprises operate on the same technology and produce identical products. At the same time, the wastewater of these enterprises is significantly different in composition. Concentration of suspended solids varies from 450 to 3500 mg/l, COD values from 1000 to 8400 mg/l, and BOD5 from 600 to 3000 mg/l. There are coagulation thresholds are determined for each of the studied enterprises. Obtained results are summarized in graphs depicting the effect of initial effluent concentrations on the coagulation threshold of each of the studied samples. Obtained results are summarized in graphs were constructed and curve equations that describe changes in the coagulant dose with a change in the concentration of contaminants in the initial effluent were proposed. Obtained equations can be used for predicting required dose of aluminum polyoxychloride coagulate for wastewater with known concentration of suspended solids, COD or BOD5. This information can be used at the design stages of new local treatment plants of poultry meat processing sewage, and during the technical re-equipment of treatment plants.

Metal Adsorption in Biomass: Fundamentals and Application

In this chapter the adsorption fundamentals using biomass as adsorbents in the removal of metallic ions are presented. The research as shows the importance of many factors that affects the adsorption, such as the biomass superficial area, system temperature, pH, initial concentration of the metal, biomass amount and status (living or dead). The study was directed at the approach of two applications usingSaccharomyces cerevisiaeyeast in the adsorption of Cd2+metal ions. In the first application it is discussed the influence of the pH of the medium and the biomass status (living or dead) in the adsorption of Cd2+, in batch. In the second application, it was studied the adsorption of Cd2+metallic ions through theSaccharomyces cerevisiaeyeast immobilized in chitosan, in fixed bed, where the influence inlet mass flow rate and the initial effluent concentration on the adsorption capacity and percentage of Cd2+ions removal are evaluated.The studies realized are supported by statistical analysis with 95% confidence intervals.

Application of Chitosan and Activated Carbon Nano-composite in Removal of Nitrite, Phosphate, and Ammonia From Aquaculture Wastewater

Developing an adsorbent with natural components is one of the effective methods to reduce the amount of wastewater pollutants. Wastewater reuse can improve the quality of water prior to entering the natural environment. The aim of this study was to evaluate the efficiency of chitosan nano-composite and activated carbon adsorbent in the removal of nitrite, phosphate, and ammonia pollutants from fish farms of Aq-Qala. To prepare the adsorbents, the shrimp shells were converted to nano-chitosan. The date palm kernel was prepared and activated with oxalic acid in pyrolysis furnace by injecting nitrogen gas into activated carbon, then, the nano-composite was prepared from nanochitosan and activated carbon. A field-laboratory study was conducted during the winter of 2018, and then, batches of synthesized nano-composite were investigated and the effects of pH, initial effluent concentration, and adsorption time were investigated. The experiments were performed in the pH range of 5-8, effluent concentration of 25-100 mg/L, and contact time of 15-90 minutes. The results showed that at optimum conditions (pH of 7, effluent concentration of 50 mg/L, and contact time of 60 minutes), the highest removal percentage and adsorption capacity for nitrite, phosphate, and ammonia contaminants were 99.98%, 99.77%, and 65.65%, and 6.65, 6.14, and 7.32 mg/g , respectively. Due to the high removal percentage (99.98%) of the chitosan and activated carbon nano-composite, the adsorbent was highly capable of removing pollutants (nitrite, phosphate, and ammonia).

Wastewater treatment using adsorption process in column for agricultural purposes

Water is essential for life, important for the ecosystem and it is in great demand due to its scarcity. This study explored the reuse of the wastewater of the Water Treatment Plant in Gramame for agricultural purposes. A qualitative and quantitative investigation of the effluent was carried out through the characterization of its physical and chemical parameters, comparing the results to what is allowed by the current legislation, CONAMA Resolution 357/2005. After this process, the activated charcoal of coco-da-baia mesocarp, adsorbent material, was prepared and tested in a filter system in a column with a continuous flow and ascendant entrance, in which the kinetic effect was evaluated. This technique was evaluated by correlating the reduced values in the adsorption material, respecting the initial effluent concentration, obtaining a reduction of 50% in the hardness, 87.5% in chloride and 66.6% in acidity. These results verified the adequacy of the technique in potential hydrogenation (pH) and abrupt reduction of color and turbidity. This treatment is suggested to qualify the effluent for use in agricultural, safe for humans and the environment. The adsorbent substrate efficiency was verified by correlating it with the Thomas isothermal model.

COLOR REMOVAL FROM PULP MILL EFFLUENT USING COAL ASH PRODUCED FROM GEORGIA COAL COMBUSTION PLANTS

In this study, Coal Fly Ash (CFA), a byproduct of coal combustion power plants, was used as an adsorbent to remove color from locally-obtained pulp mill effluent (PME). Batch adsorption studies were conducted to determine the adsorption parameters that would result in the maximum color removal from PME at the lowest CFA dosage and process cost. The effects of operating variables on color removal were studied by varying: 1) CFA dosage, 2) initial PME pH, and 3) contact time. The findings indicate that the optimum CFA dosage for cost-effective color removal was 100.0 g/L (80.5% removal) given an initial effluent color concentration below 900 mg/L Pt-Co color units. For effluent samples with a color concentration over 900 mg/L Pt-Co color units, the optimum CFA dosage was 250.0 g/L (80.4% removal). In addition, no pH adjustment of the PME was required for maximum color removal. A kinetic study showed that color removal by CFA occurred rapidly in the first hour, and adsorption equilibrium was achieved at 24 hours. Additionally, the kinetic and isotherm adsorption data was best described by the Ho et al. kinetic model and the Langmuir and Freundlich isotherm models, respectively. Overall, this research found CFA to be a promising low-cost adsorbent for the removal of color from PME.

Towards zero waste production in the paint industry wastewater using an agro-based material in the treatment train.

An attempt has been made to evaluate the use of natural, agro-based material, Moringa oleifera as a coagulant in the treatment of recreated water-based paint effluent. The treatment train sequence comprising coagulation, flocculation, sedimentation, sand filtration, and membrane filtration was used. The efficiency was evaluated in terms of color and turbidity. The influence of experimental parameters such as eluent type, eluent concentration, coagulant dose, coagulant-eluate volume, initial effluent pH, and initial effluent concentration was examined. The recommended conditions to yield maximum removal efficiency are 80mL of eluate prepared using 3g of M. oleifera seed powder and 1N NaCl, under actual pH, to treat a liter of effluent. The treated supernatant from coagulation unit was passed through a sand filtration setup and a membrane filtration, with a maximum removal of color above 95%. The results affirmed the positive coagulation properties of M. oleifera, which could serve as a better alternative for chemical coagulant. The optimized treatment conditions derived for the recreated paint effluent were applied in the real paint effluent treatment. An opportunity was identified for re-using treated wastewater, as a cooling fluid and a diluting agent for lower quality paints.The results affirmed the positive coagulation properties of M. oleifera, which could serve as a better alternative for chemical coagulant. Graphical abstract ᅟ.

COD and Color Removal from Real Dyeing Wastewater by Ozonation

ABSTRACT: Ozonation of real dye wastewater for removal of color and COD reduction covering a wide range in operating parameters forms the scope of the present work. The influence of parameters such as influent pH, ozone flow rate and initial effluent concentration on ozonation efficiency has been critically examined. It has been observed from the present investigation that a maximum of COD removal efficiency of 92.5% has been achieved under optimum operating conditions (pH=11; ozone flow rate: 6×10−3 m3/minute). Further the biodegradability index of the dye effluent has increased from an initial value of 0.18 to 0.49 during ozonation indicating favorable adaptation of ozonation as a primer to the biochemical technique to enhance the efficiency of biochemical treatment.

Combination of electrocoagulation with advanced oxidation processes for the treatment of distillery industrial effluent

The treatment of distillery industrial effluent by means various combinations of electrocoagulation with Advanced Oxidation Processes (AOPs) such as ozonation, electrocoagulation, peroxi–electrocoagulation, photo–electrocoagulation, ozone–electrocoagulation and peroxi–photo–electrocoagulation process on the removal of percentage color, COD and energy consumption. The effects of various operating parameters such as ozone flow rate (5 to 15 LPM), initial effluent pH (2 to 10), current density (0.10 to 0.50A/dm2) and H2O2 concentration (50 to 500mg/L) on the removal of pollutant were studied in this study. Moreover comparison of all the processes in terms of color removal, COD removal and energy consumption was also carried out. The experimental results showed that100% of color and COD removal could be achieved by ozone–electrocoagulation process with an energy consumption of 5.7kWh/m3 within four hours of reaction time. The extent of color and COD removal was analyzed using a UV/vis spectrophotometer and closed reflux method.

Modeling and optimization by response surface methodology and neural network–genetic algorithm for decolorization of real textile dye effluent using Pleurotus ostreatus: a comparison study

This study focuses on the modeling and optimization of the decolorization procedure of real textile dye. The percentage of decolorization of effluent in the Erlenmeyer flask level, as obtained by both response surface methodology (RSM) and artificial neural network (ANN), was determined and subjected to comparative evaluation. The effect of independent variables such as pH (5–8), self-immobilized Pleurotus ostreatus, bead volume (30–50%) (Vb/Vr), and initial effluent concentration (50–100%) was examined using three-level Box–Behnken design. A similar design was utilized to train a feed-forward multilayered perceptron with back-propagation algorithm. Errors were computed using error functions, and the values obtained for RSM and ANN were compared. The maximum percentage decolorization and COD reduction of effluent under optimized conditions over a 24-h period were observed as 89 and 72%, respectively. The parameters optimized in the flask level were adapted in an inverse fluidized bed bioreactor of 6 l working volume, in which the quantity of decolorization and COD reduction over a 24-h period was observed as 92 and 76%, respectively.

How to dose powdered activated carbon in deep bed filtration for efficient micropollutant removal

Direct addition of powdered activated carbon (PAC) to the inlet of a deep bed filter represents an energy- and space-saving option to remove organic micropollutants (OMPs) during advanced wastewater treatment or drinking water purification. In this lab-scale study, continuous dosing, preconditioning a filter with PAC and combinations thereof were investigated as possible dosing modes with respect to OMP adsorption efficiency. Continuous dosing resulted in decreasing effluent concentrations with increasing filter runtime due to adsorption onto accumulating PAC in the filter bed. Approximately constant removal levels were achieved at longer filter runtimes, which were mainly determined by the dose of fresh PAC, rather than the total PAC amount embedded. The highest effluent concentrations were observed during the initial filtration stage. Meanwhile, preconditioning led to complete OMP adsorption at the beginning of filtration and subsequent gradual OMP breakthrough. PAC distribution in the pumice filter was determined by the loss on ignition of PAC and pumice and was shown to be relevant for adsorption efficiency. Preconditioning with turbulent upflow led to a homogenous PAC distribution and improved OMP adsorption significantly. Combining partial preconditioning and continuous dosing led to low initial effluent concentrations, but ultimately achieved concentrations similar to filter runs without preconditioning. Furthermore, a dosing stop prior to the end of filtration was suitable to increase PAC efficiency without affecting overall OMP removals.

Textile Effluent Treatment by Agricultural Solid Waste

Adsorption of dye is an alternative technology to remove color from wastewater. An abundantly available agricultural waste which finds little utility has a potential as a cheap adsorbent for dye removal from textile effluents and can be utilized for wastes management. In the present work, adsorption studies were made in treating the dye solutions of Basic blue (BB69) textile dyes by using okra waste. Effects of particle size, initial effluent concentration and temperature have been investigated experimentally and the suitable conditions were selected. A brief economic comparison between activated carbon and okra waste is also reported. The results were compared with that in the literature by using activated carbon. Adsorption parameters were determined using both Langmuir and Freundlich isotherms. The isothermal data followed the Langmuir and Freundlich models. The results obtained were fitted by Langmuir model since monolayer formation observed and the parameters were estimated. It is concluded that okra solid waste could be employed as low– cost and effective sorbent for removal of Basic blue dye from aqueous solution of textile industries.