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The performance of carbon mineral-combined adsorbents in a batch and fixed column study was examined for removing chemical oxygen demand (COD) and ammoniacal nitrogen (NH3-N), which typically found in landfill leachate. The batch experiment was carried out using various factors including adsorbent dosages and retention time, while column performance was evaluated by optimizing the influent flow rate. The surface of the composite adsorbent was examined using X-ray fluorescence (XRF), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) to determine any changes before and after column operations. The XRF analysis of the composite adsorbent reveals a high concentration of calcium oxide and silica oxide as the primary compounds. The main functional groups in the composite adsorbent included O–H, N–H, O–C, C–N, C–O, and Si–O–Si. The SEM analysis revealed that the composite adsorbent contains heterogeneous pores and a rough surface. The reduction rates achieved were 86% for COD, with an optimum adsorption capacity of 31.3 mgg−1, and 80% for NH3-N, with an optimum adsorption capacity of 29.8 mgg−1. The breakthrough capacities for COD and NH3-N adsorption were 6.55 and 4.24 mgg−1, respectively. However, optimal empty-bed contact times (EBCTs) in minutes were 480. The performance efficiency of the column for COD and NH3-N was 0.9978% and 0.9913%, by utilizing fresh composite adsorbent, and these number figures increased to (≥ 0.9998%) respectively after the regeneration process. The Adams–Bohart constant for COD from 5.30 × 10–6 to 4.92 × 10–6 mL/min-mg and NH3-N from 2.90 × 10–5 to 4.52 × 10–5 mL/min-mg respectively was found to increase with increasing flow rates from 1.5 to 3.0 mLmin−1. Therefore, COD and NH3-N adsorption on composite adsorbent at flow rates of 1.5 mLmin−1 was considered appropriate from the context of this study. In summary, this research has successfully shown that the use of composites as an adsorbent is a viable and suitable for the removal of COD and NH3-N from leachate, indicating their potential for use in real-world industrial wastewater treatment could further enhance their practical applications. [ABSTRACT FROM AUTHOR]

Abstract The performance of carbon mineral-combined adsorbents in a batch and fixed column study was examined for removing chemical oxygen demand (COD) and ammoniacal nitrogen (NH3-N), which typically found in landfill leachate. The batch experiment was carried out using various factors including adsorbent dosages and retention time, while column performance was evaluated by optimizing the influent flow rate. The surface of the composite adsorbent was examined using X-ray fluorescence (XRF), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM) to determine any changes before and after column operations. The XRF analysis of the composite adsorbent reveals a high concentration of calcium oxide and silica oxide as the primary compounds. The main functional groups in the composite adsorbent included O–H, N–H, O–C, C–N, C–O, and Si–O–Si. The SEM analysis revealed that the composite adsorbent contains heterogeneous pores and a rough surface. The reduction rates achieved were 86% for COD, with an optimum adsorption capacity of 31.3 mgg−1, and 80% for NH3-N, with an optimum adsorption capacity of 29.8 mgg−1. The breakthrough capacities for COD and NH3-N adsorption were 6.55 and 4.24 mgg−1, respectively. However, optimal empty-bed contact times (EBCTs) in minutes were 480. The performance efficiency of the column for COD and NH3-N was 0.9978% and 0.9913%, by utilizing fresh composite adsorbent, and these number figures increased to (≥ 0.9998%) respectively after the regeneration process. The Adams–Bohart constant for COD from 5.30 × 10–6 to 4.92 × 10–6 mL/min-mg and NH3-N from 2.90 × 10–5 to 4.52 × 10–5 mL/min-mg respectively was found to increase with increasing flow rates from 1.5 to 3.0 mLmin−1. Therefore, COD and NH3-N adsorption on composite adsorbent at flow rates of 1.5 mLmin−1 was considered appropriate from the context of this study. In summary, this research has successfully shown that the use of composites as an adsorbent is a viable and suitable for the removal of COD and NH3-N from leachate, indicating their potential for use in real-world industrial wastewater treatment could further enhance their practical applications.

We determined the most suitable level of inclusion of spineless cactus in silage of BRS capiaçu on the fermentative profile and nutritional value of the silage produced. The treatments consisted of the inclusion of spineless cactus (Opuntia spp.) in BRS capiaçu grass ensilaged with increasing proportions (15%, 30%, 45%, and 60% of natural matter-NM) and a control treatment. A completely randomized design with five treatments and eight replications was used. The BRS capiaçu grass was harvested after 100 days of regrowth. For the silage, experimental PVC silos of known weights, 50 cm long and 10 cm in diameter, were used. The inclusion of spineless cactus in BRS capiaçu grass ensilage resulted in a linear increase in pH (P < 0.01), ammonia nitrogen content (P < 0.01), and effluent losses (P < 0.01). Quadratic effects were observed for lactic acid (P < 0.01) and acetic acid (P < 0.01), with respective maximum points for 22% and 24%. The highest values of the digestibility of dry matter (DM), organic matter, and neutral detergent fibre were found for inclusion levels of 47.11%, 42.35%, and 35.44%, respectively. The most suitable inclusion level was between 15 and 30% of NM. [ABSTRACT FROM AUTHOR]

Determining the behavior of inorganic nitrogen compounds at plot scale is a useful tool to predict the consequences of the discharge of nitrogen-enrich effluent in the vadose zone and groundwater at a larger scale. In this work, field data were collected from an experimental plot located on the periphery of an ammonia and urea fertilizer manufacturing industry. Water flow and solute transport were simulated with HYDRUS 2D/3D. Numerical simulation allowed estimating the main processes and transformations that ammoniacal nitrogen underwent during its transport in the soil. Soil pH was in the range of 8.8 and 9.8 being both species of ammoniacal nitrogen (N-NH3 and N-NH4) present in the soil. The process that was most relevant in the fate of nitrogen was volatilization (33.7% of total nitrogen applied). Most of the nitrogen that remained in the soil was nitrified (30.6% of total nitrogen applied). Leaching of nitrogen to the aquifer accounted for 4.5% of total nitrogen applied, mainly as ammoniacal nitrogen. Nitrification rates in the industrial zone were very low; thus, ammoniacal nitrogen had longer residence times in the vadose zone facilitating its leaching into the aquifer. As the predominant specie of ammoniacal nitrogen was N-NH3 (at pH > 9.3), its great solubility in water grants a higher mobility than NH4+, due to the minimization of retardation. In the future, further data collection is needed to estimate robust and representative input parameters for a larger scale numerical model of reactive nitrogen transport. Solute transport parameters applied in this research may vary considerably for other sites with different conditions. [ABSTRACT FROM AUTHOR]

ABSTRACT The objective was to examine the effects of supplementing different levels of zeolite in the diet of laying hens during the laying phase, at 54 weeks of age, on production performance, egg quality, ammonia volatilization, excreta pH, blood parameters, weight, and organ morphometry. The treatments consisted of a control diet free of zeolite and five diets including increasing levels of zeolite (0.7, 1.4, 2.1, 2.8, and 3.5%). A completely randomized design was adopted with eight replicates of five birds per plot, totaling 240 laying hens, for four 28-day periods. Results were subjected to ANOVA, Dunnett’s test, and regression analysis at 5% probability. The zeolite levels had no significant effect on production performance, egg quality, and blood parameters. The zeolite levels have a significant effect on ammonia volatilization, excreta pH, liver weight, and organ morphometry specifically on the intestinal length. Ammonia and pH reached a linear plateau. Ammoniacal nitrogen levels in the excreta differed from that observed in the control group at all zeolite levels, whereas the pH was lowest at the zeolite inclusion levels of 0.7 and 1.4%. Ammonia volatilization and the pH value of the excreta decreased by 46.9% and 4.6%, when the laying hens consumed diets with 0.93% and 1.19% zeolite, respectively. There was an effect on the relative weight of the organs, with higher liver yield and intestinal length provided by zeolite inclusion. Therefore, zeolite can be included in the diet of commercial layers at up to 0.93% without affecting their production performance or egg quality.

This research focused on the application of a fixed bed column filled with immobilized titanium oxide-loaded almond shell carbon (TiO2@ASC) for the treatment of leachate. The adsorption performance of synthesized TiO2@ASC in fixed bed column is analyzed using adsorption experiments and modeling study. The characteristics of synthesized materials are determined by several instrumental techniques like BET, XRD, FTIR, and FESEM-EDX. The flow rate, initial concentration of COD and NH3-N, and bed height were optimized to determine the effectiveness of leachate treatment. The linear bed depth service time (BDST) plots equations with a correlation coefficient of greater than 0.98 confirmed the model's accuracy for COD and NH3-N adsorption in column structure. The adsorption process was found to be well predicted by an artificial neural network (ANN) model with a root mean square error of 0.0172 and 0.0167 for COD and NH3-N reduction, respectively. The immobilized adsorbent was regenerated using HCl and was found to be reusable for up to three cycles, promoting material sustainability. This study is aimed to contribute towards SDG 6 and SDG11 by United Nations Sustainable Development Goals. [ABSTRACT FROM AUTHOR]

This present study investigated the removal of COD and ammoniacal nitrogen (NH4+–N) from tannery deliming wastewater (TDLWW) through microbes immobilized carbon consisted a bioreactor (MICCR) and reactive struvite crystallization process. Initially, 90% of the organic content of TDLWW was removed using a MICCR reactor at 24 h retention time. Nanoporous carbon (NPC) was used as the carrier matrix for the MICCR reactor. SEM and AFM images of NPC used in the MICCR reactor identify different microorganisms on its surface. The microbial profile of NPC used in the MICCR was analyzed, and the relative abundance is phyla Firmicutes, 25.64%; Proteobacteria, 43.68%; Bacteroidetes, 6.58%; Cyanobacteria, 2.22%; Actinobacteria, 2.34% reason for organic removal. The removal of organics follows the pseudo-second-order rate kinetics with the rate constant of 1.75 × 10−3 L COD−1 h−1. For the reactive struvite crystallization, MgO and Na2HPO4.2H2O were taken as the precipitating agents. The optimum molar ratio for the maximum conversion of NH4+–N into struvite was obtained as 1:1.4:1.4 (NH4+–N:MgO:Na2HPO4.2H2O). The volume of struvite precipitate was 48.5 mL/L of TDLWW, and the dry weight was 8.89 g/L. More than 93% of NH4+–N was converted as the struvite fertilizer. The conversion of NH4+–N into struvite follows the pseudo-first-order rate kinetics with the rate constant of 1.67 × 10−2 min−1. Despite the conversion of NH4+–N into struvite, COD removal was observed, which confirms the conversion of organic nitrogen into struvite. The struvite was evaluated using SEM, XRD, TGA, DSC, and FT-IR spectroscopic analysis. Hence, the integrated MICCR and the reactive struvite crystallization process can be applied to manage tannery deliming wastewater. [ABSTRACT FROM AUTHOR]

Ammoniacal nitrogen is an environmental pollutant present in various effluents, such as landfill leachate. It is possible to use ion‐exchange resins in systems for tertiary treatment of effluents containing NH4+ ions and as support for NH3 recovery after treatment of these effluents by employing air stripping. This article presents an exploratory study of sorption of NH4+ ions by sulfonic resins prepared from styrene‐divinylbenzene (Sty‐DVB) copolymers with varied morphological structures: hypercrosslinked resin, a macroporous copolymer prepared by conventional aqueous suspension polymerization, and a polyHIPE copolymer. These three resins are sulfonated by employing concentrated sulfuric acid. The sulfonic resin derived from hypercrosslinked resin has the highest cation exchange capacity (5.06 meq g−1) and is selected for batch studies and column tests. The best result (removal rate of 87%) is achieved with 20 g of resin, time of 20 min, and concentration of 100 ppm. Kinetic behavior and sorption processes are best described by the pseudo‐second‐order, Weber–Morris intraparticle diffusion, and Langmuir models. The saturation point occurs when 900 mL of the NH4+ solution at 2500 ppm (15 mL min−1) is percolated through the column. The working capacity of this resin is 14.06 g cm−3. The resin can be reused during five cycles with removal efficiency between 71% and 82%. [ABSTRACT FROM AUTHOR]

The release of high amount of nitrogen and phosphorous from agricultural, municipal and industrial sewage into natural water body is the major source of eutrophication in aquatic ecosystems. This leads to the depletion of oxygen, cyanobacteria bloom and proliferation of aquatic weed plants, and destruction of water ecosystem. Therefore, effective treatment of municipal wastewater is crucial prior to discharge into natural water bodies in order to prevent pollution, and to meet the wastewater acceptable limits set by government and Environmental Protection Agencies. The present study evaluates the performance of varying weight of S. molesta plants in phytoremediation of treated domestic wastewater samples for 14 days at 24 h retention time. Physicochemical analysis such as turbidity, phosphate, ammoniacal nitrogen and nitrate tests were conducted on the wastewater samples according to spectrophotometric methods. Also, S. molesta plants were harvested once in a week and the relative growth rate (RGR) was calculated. The outcome of the study indicated that the treated domestic wastewater from the sewage treatment plant contains pollutants that stimulates the growth of S. molesta plants. Similarly, the highest reduction efficiency of up to 97.7%, 99.7%, 99% and 90.6% was observed for turbidity, phosphate, ammoniacal nitrogen and nitrate, respectively. In addition, the outcome of the study also demonstrated that S. molesta plants with the highest weight (280 g) were more efficient in removal of the excess nutrient present in the influent samples. Furthermore, the free energy content in the wastewater provided a suitable consortium for the plant cultivation and growth. Therefore, this method can be used for lab-scale production of wastewater-based biomass for the generation of biofuels.

The objective of this study was to evaluate the dry matter intake (DMI), intake of nutrients and in vivo ruminal fermentation in wethers fed diets without or with 2 or 4 % of marine microalgae meal (Schizochytrium sp.) as a source of docosahexaenoic polyunsaturated fatty acid (DHA; C22:6 n-3), as well as the total gas production and digestibility of the experimental diets using in vitro techniques. Six Santa Inês wethers with a body weight of 55.6 ± 5.20 kg and 18 months of age fitted with a ruminal cannula, were used and housed in individual stalls. The experimental design consisted of a double 3 ×3 Latin square (three treatments and three periods) with each experimental period lasting 21 days (14 days for adaptation to diets, 5 days for sample collection and 2 days of blank time between periods), for a total of 63 days. Animals fed 4 % microalgae meal showed lower DMI (P<0.05; 1,14 vs. 0,86 kg/d) and lower intake of nutrients (P<0.05), except for ether extract (EE; P=0.967), compared to animals not fed microalgae. Wethers that were not fed marine microalgae had lower ruminal pH just two hours after feeding (P=0.042) and lower concentrations of ammoniacal nitrogen (NH 3 -N) in the ruminal fluid at all sampling times (P = 0.011) compared to wethers fed diets with 2 and 4 % level inclusion. The addition of marine microalgae meal did not have an effect on heat production and in vitro gas production (P>0.05). The in vitro digestibility of non-fibrous carbohydrates (NFC) increased (P = 0.033) with the inclusion of marine microalgae in the diet, being higher in the 4 % treatment compared to the others. Additionally, marine microalgae meal significantly reduced (P = 0.002; 0.55–0.47 g/g of DM) the in vitro digestibility of neutral detergent fiber corrected for ash and protein (NDF). The inclusion of marine microalgae meal Schizochytrium sp. as a DHA source did not negatively affect ruminal fermentation. However, it compromised dry matter and nutrients intake, as well as NDF digestibility in animals fed 4 % microalgae while a reduction on DMI as well as intake of nutrients at 2 % inclusion was not significant. Therefore, it is recommended to use marine microalgae meal in the feeding of wethers under tropical conditions at a concentration of 2 % of the diet. • Animals fed 4 % of microalgae meal had lower DM and nutrients intake. • Sheep fed with marine microalgae had higher pH and NH 3 -N in the ruminal fluid after feeding. • Inclusion of microalgae in diets for ruminants does not interfere with digestibility, short-chain fatty acids and methane production. [ABSTRACT FROM AUTHOR]

The effluent from the rubber processing industry usually contains a high concentration of organic compounds, suspended solids, color, nitrogen, and other pollutants. If an excessive amount of ammonia nitrogen is discharged into bodies of water, it may cause eutrophication and the death of various aquatic creatures. The goal of this experimental design was to investigate the effectiveness of zeolite for ammoniacal nitrogen, chemical oxygen demand (COD), and color removal from rubber processing industry effluent. The samples of rubber processing industry effluent for this study were acquired directly from the discharging point of a manufacturer in Kluang, Malaysia. The effects of optimal adsorbent dose, shaken speed, contact time, and pH were determined for ammoniacal nitrogen, COD and color removal. The obtained result reveals that the best batch adsorption experiment of ammoniacal nitrogen, COD, and color removal was attained at pH 7, ZEO dosage 4.0 g, contact time 120 min, and shaken speed 200 rpm respectively. The best efficiency removal of ammoniacal nitrogen, COD, and color was achieved based on dosage generally in the range of 75% for ammoniacal nitrogen, 69% for COD, and 79% for the color of all batch experiments conducted. The kinetic equilibrium model data fitted well with the pseudo-first and second model. The pseudo-second-order better fitted the equilibrium data over the entire concentration range studied. The pseudo-second-order described the best coefficient of determination compared to the pseudo-first-order. The coefficient of determination for pseudo-second-order was generally in the range of 0.9958 for ammoniacal nitrogen, 0.9978 for COD, and 0.9984 for the color of all kinetics studies conducted. [ABSTRACT FROM AUTHOR]

Organic and inorganic pollutants in sanitary landfill leachates are harmful to the environment and human health and must be removed before reaching receptive waterbodies. Thus, this study aimed to determine the adsorption capacity of granular activated carbon (GAC) mixed with bentonite clay (BC) for the removal of chemical oxygen demand (COD), ammoniacal nitrogen (N-NH3), and total chromium (Cr) from the leachate generated in the Sanitary Landfill of Campina Grande, Paraíba, Brazil. Different compositions of these materials were tested, and the best one was determined based on central composite rotational design (CCRD) type 22. From this result, batch adsorption tests (isotherm and kinetics) were conducted using an adsorbing material:leachate ratio of 1:10, agitated at 130 rpm at 26°C ± 2°C. The isothermal behavior of the adsorption process was evaluated using linear, Langmuir, and Freundlich models, whereas the sorption mechanisms and rates were evaluated by pseudo-first-order and pseudo-second-order kinetic models. The CCRD results indicated that the best composition for the batch adsorption tests was 75% GAC + 25% BC. The maximum adsorption capacities obtained were approximately 29.00, 2.60, and 0.78 mg g-1 and the removal efficiencies were 80%-94%, 16.8%-30.4%, and 96.7%-99.7%, for COD, N-NH3, and Cr, respectively. The Freundlich model exhibited the best adjustment for COD, N-NH3, and Cr. Moreover, the pseudo-first-order kinetic model exhibited an acceptable adjustment only to COD, whereas the pseudo-second-order kinetic model was better adjusted to N-NH3, and Cr results. [ABSTRACT FROM AUTHOR]

In anaerobic digestion of agro-industrial effluents and livestock wastes, concentrations of ammoniacal nitrogen above 800 mg L−1 are reported to lead to the eutrophication of water bodies. Through the metabolic versatility of microalgae, this nitrogen source can be used and removed, producing carotenoids, phycobiliproteins, polyhydroxyalkanoates, and fatty acids of industrial interest. The challenge of making it feasible is the toxicity of ammoniacal nitrogen to microalgae. Therefore, three strategies were evaluated. The first one was to find species of cyanobacteria with high ammoniacal nitrogen removal efficiency comparing Arthrospira platensis, Synechocystis D202, and Spirulina labyrinthiformis cultivations. The most promising species was cultivated in the second strategy, where cell acclimatization and increasing of the inoculum were evaluated. The cultivation condition that culminated in the best efficiency of ammoniacal nitrogen removal was combined with the third strategy, which consisted of conducting the fed-batch bioprocess. In the batch mode, ammoniacal nitrogen was supplied only once in one fed and was present in high initial concentrations. In fed-batch, multiple feedings with low concentrations of ammoniacal nitrogen were used to decrease the inhibitory effect of ammoniacal nitrogen. Arthrospira platensis showed high potential for ammoniacal nitrogen removal. Using the highest initial cell concentration of Arthrospira platensis cultivated by fed-batch, an increase in the consumption of NH3 to 165.1 ± 1.8 mg L−1 and an ammoniacal nitrogen removal efficiency close to 90% were observed. Under this condition, 180.52 ± 11.67 mg g−1 of phycocyanin was attained. Also, the fed-batch cultivations have the potential to reduce the biomass cost production by 33% in comparison to batch experiments. [ABSTRACT FROM AUTHOR]

Landfills are an important physical facility to disposing municipal solid waste in developing countries. Although, such landfills are correlated with leachate production, which if left untreated, can pose a serious threat to human health and affect the ecosystem in the aquatic life. In the present research study, green mussel adsorbent was explored for the treatment of stabilized landfill leachate. To remove the organic constituent (COD) and ammoniacal nitrogen (NH3–N). The optimum agitation speed, pH, and adsorbent dosage were tested using particle size ranges from 2.00 mm to 3.35 mm. The physicochemical characterization was then determined. The best optimum shaking condition was determined at 200 rpm, pH and adsorbent dosages were 7 and 2.0 g. The optimum percentage removal values for COD are 40% at 200 rpm, 60% at pH 7, and 65% at 2.0 g and the optimum percentage removal values for NH3–N are 30% at 200 rpm, 50% at pH 7, and 45% at 2.0 g, respectively. Generally, the finding results revealed that the Langmuir model adsorption was slightly better fitted and suitable for organic constituent (COD) and Freundlich was good for ammoniacal nitrogen reduction in terms of coefficient of determination (R²). Langmuir adsorption coefficient of determination (R²) for COD are 0.9979 and Freundlich adsorption coefficient of determination (R²) for ammoniacal nitrogen are 0.9938 respectively. This implies that adsorbate adsorption occurs by monolayer adsorption on a homogeneous surface. Therefore, it is proposed that kinetic adsorption be taken into account for further research to examine the organic constituents (COD) and ammoniacal nitrogen process on to the green mussel (Perna viridis) media respectively. Landfills are an important physical facility to disposing municipal solid waste in developing countries. Although, such landfills are correlated with leachate production, which if left untreated, can pose a serious threat to human health and affect the ecosystem in the aquatic life. In the present research study, green mussel adsorbent was explored for the treatment of stabilized landfill leachate. To remove the organic constituent (COD) and ammoniacal nitrogen (NH3–N). The optimum agitation speed, pH, and adsorbent dosage were tested using particle size ranges from 2.00 mm to 3.35 mm. The physicochemical characterization was then determined. The best optimum shaking condition was determined at 200 rpm, pH and adsorbent dosages were 7 and 2.0 g. The optimum percentage removal values for COD are 40% at 200 rpm, 60% at pH 7, and 65% at 2.0 g and the optimum percentage removal values for NH3–N are 30% at 200 rpm, 50% at pH 7, and 45% at 2.0 g, respectively. Generally, the finding results revealed that the Langmuir model adsorption was slightly better fitted and suitable for organic constituent (COD) and Freundlich was good for ammoniacal nitrogen reduction in terms of coefficient of determination (R²). Langmuir adsorption coefficient of determination (R²) for COD are 0.9979 and Freundlich adsorption coefficient of determination (R²) for ammoniacal nitrogen are 0.9938 respectively. This implies that adsorbate adsorption occurs by monolayer adsorption on a homogeneous surface. Therefore, it is proposed that kinetic adsorption be taken into account for further research to examine the organic constituents (COD) and ammoniacal nitrogen process on to the green mussel (Perna viridis) media respectively. [ABSTRACT FROM AUTHOR]

Abstract Eutrophication is a serious environmental issue that needs urgent concern. There is necessity to treat wastewater with high ammoniacal nitrogen (AN) concentration to the permissible standard limit to protect the aquatic ecosystem. This study investigated the optimum condition for AN removal from wastewater using Eichhornia crassipes-based phytoremediation process. Face-centered central composite design (CCD) was employed as the experimental design, in which four operational variables including pH (4–10), retention time (2–14 days), macrophyte density (5–30 g/L) and salinity (0–5 g NaCl/L) were involved in the study, while five responses were investigated, namely AN removal efficiency (Y 1), fresh biomass growth (Y 2), COD (Y 3), BOD (Y 4) and TSS (Y 5). AN removal was the main focus in this study. Through numerical optimization, the highest AN removal efficiency of 77.48% (initial AN concentration = 40 mg/L) was obtained at the following optimum condition: pH 8.51, retention time of 8.47 days, macrophyte density of 21.39 g/L and salinity of 0 g NaCl/L. The values predicted from the models agreed satisfactorily with the experimental values, which implied that response surface methodology was reliable and practical for experimental design developed using optimization of the phytoremediation process. The validation experiment using real semiconductor effluent further supported the high potential of the E. crassipes-based phytoremediation system to remove AN and other organic pollutants in this industrial effluent under optimal condition.

Abstract The untreated wastewater from the dye industry having high ammoniacal nitrogen and chemical oxygen demand (COD) significantly pollutes the receiving water, such as a river, having major ill implications on the aquatic environment. The present study is undertaken to address this problem. It investigates the effectiveness of Fenton reagent in simultaneous treatment (removal) of ammoniacal nitrogen and COD present in the wastewater by varying the parameters like pH, concentration of Fe 2+ and H2O2 and their molar ratio. The reaction time for all the experiments was kept 60 min. The experimental analysis in terms of calculating the residual % of ammoniacal nitrogen and COD revealed that the maximum reduction occurred at pH 3. At this pH, further set of experiments were performed by varying the molar doses of Fe2+/H2O2 as 1:1, 3:3 and 5:5, and the results reveal that the maximum reduction in both ammoniacal nitrogen and COD happens at molar dose of 3:3. To understand the effect of the concentration of Fe2+ and H2O2 on the respective removal efficiency, set of experiments were performed by taking the molar ratio of Fe2+/H2O2 as 2:1, 3:1, 5:1, 1:2, 1:3 and 1:5. The experimental analysis reveals that the maximum reduction happened at molar ratio 1:3. Fenton process can mineralize the pollutants up to 75.8% and 78.6% for ammoniacal nitrogen and COD removal. The findings of the study would be of great use for planning and optimizing the wastewater treatment facility for the dye intermediate industry.

[Display omitted] The release of high amount of nitrogen and phosphorous from agricultural, municipal and industrial sewage into natural water body is the major source of eutrophication in aquatic ecosystems. This leads to the depletion of oxygen, cyanobacteria bloom and proliferation of aquatic weed plants, and destruction of water ecosystem. Therefore, effective treatment of municipal wastewater is crucial prior to discharge into natural water bodies in order to prevent pollution, and to meet the wastewater acceptable limits set by government and Environmental Protection Agencies. The present study evaluates the performance of varying weight of S. molesta plants in phytoremediation of treated domestic wastewater samples for 14 days at 24 h retention time. Physicochemical analysis such as turbidity, phosphate, ammoniacal nitrogen and nitrate tests were conducted on the wastewater samples according to spectrophotometric methods. Also, S. molesta plants were harvested once in a week and the relative growth rate (RGR) was calculated. The outcome of the study indicated that the treated domestic wastewater from the sewage treatment plant contains pollutants that stimulates the growth of S. molesta plants. Similarly, the highest reduction efficiency of up to 97.7%, 99.7%, 99% and 90.6% was observed for turbidity, phosphate, ammoniacal nitrogen and nitrate, respectively. In addition, the outcome of the study also demonstrated that S. molesta plants with the highest weight (280 g) were more efficient in removal of the excess nutrient present in the influent samples. Furthermore, the free energy content in the wastewater provided a suitable consortium for the plant cultivation and growth. Therefore, this method can be used for lab-scale production of wastewater-based biomass for the generation of biofuels. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this work was to evaluate the effect of the residue from the extraction of propolis, added to bovine diets with increasing levels of protein, on ruminal fermentation in vitro. For this, the in vitro gas production technique was used. Incubation was carried out with inocula from three fistulated cows, in three periods. In each period, a cow received a daily dose of 100 g propolis residue. Four diets were evaluated: corn silage (control); and 25, 50, and 75% concentrate based on soybean meal. The following were determined: kinetics of rumen fermentation; dry matter degradation; production of gases, volatile fatty acids (acetate, propionate, and butyrate), methane, and ammonia nitrogen; and pH. The inclusion of 14.4, 15.1, and 9.5% propolis residue, respectively, to 25, 50, and 75% concentrate increased the production of gases from the degradation of fibrous carbohydrates, when compared with the control. The propolis residue reduces methane production and the acetate:propionate ratio at all tested concentrate inclusion levels.

Intensification of landscape use brings along the negative effects on environmental components. These include surface water pollution. The aim was to determine the effect of landscape use on the water quality of the Žitava river. It was assumed that an area with the high proportion of anthropogenic activity would negatively affect water quality. At the same time, we assumed that an area with the lower proportion of anthropogenic use and with the higher proportion of natural and semi-natural elements contributes to self-cleaning ability of the watercourse. At the four observed sites, ammoniacal nitrogen (NH4-N), nitrate-nitrogen (NO3-N), phosphate-phosphorus (PO4-P) and water conductivity were monitored. Landscape use was analysed using the database of land cover based on the CORINE Land Cover methodology. Subsequently, it was observed how the landscape use affects the water quality. It was found that the very good state, represented by the Class I water quality, is according to the measured indicators mostly present in the areas predominantly covered by forests along with extensive use of elements of the agricultural land. The area with predominance of agricultural and urbanised sites where the anthropogenic influence prevails is characterised by average water quality. As the overall water quality of the Žitava river reaches the average, it is necessary to eliminate the pollution by constructing the sewer systems in the villages through which the watercourse is passing and, in agriculture, to ensure the adherence to the legislation concerning the protection of surface water against pollution from agricultural sources.

Soil fertilization improves yield and quality of produce, but nutrient loss from fertilized soil produces alterations in the ecosystems (e.g., eutrophication); it also increases costs in the agribusiness. In this research, we developed a device from residual cellulose/polyvinyl alcohol hydrogel for the controlled release of ammoniacal nitrogen in soil. Total Kjeldahl Nitrogen (TKN) method was used to determine the fraction of nitrogen released, and the effect of the device on a bioindicator (Zea mays) was studied in greenhouse conditions. Structural damage to the device after its application to soil was analyzed using scanning electron microscopy (SEM). Kjeldahl tests showed the device released less than 15% of total nitrogen across a 60 day evaluation period, displaying a Fickian diffusion pattern. Seedlings produced two times more biomass in device-fertilized soil.

Organic matter, nutrients, and chemicals are some of the waste materials found in most domestic wastewaters. The purpose of this research was to evaluate the potentials of Pistia stratiotes, Salvinia molesta, and Eichhornia crassipes aquatic weed plants in the tertiary treatment of secondary domestic wastewater using hydroponic systems. Physicochemical analysis that considered turbidity, phosphate, ammoniacal nitrogen, and nitrate was conducted on the wastewater samples at different retention times of 6, 12, and 24 h for 14 days. The best performance was observed for a 24 h retention treatment system, with up to 91% (P. stratiotes), 94% (S. molesta), and 89.3% (E. crassipes) reduction for turbidity; 81.2% (P. stratiotes), 82.7% (S. molesta), and 88.5% (E. crassipes) for phosphate reduction; 88.66% (P. stratiotes), 90.47% (S. molesta), and 89.11% (E. crassipes) for ammoniacal nitrogen reduction; 83.6% (P. stratiotes), 92.1% (S. molesta) and 93% (E. crassipes) for nitrate reduction. Hence, the application of hydroponic systems in cultivation of the macrophytes proved to be effective in the phytoremediation process by removing the residual nutrients present in the treated secondary domestic wastewater. Additionally, this method can be used for the cultivation of plant-based biomass and other non-edible useful crops using the free nutrients content of the wastewater before its discharge into the natural environment. [ABSTRACT FROM AUTHOR]

Landfills are the main option for waste disposal all over the world. Most of the landfill sites across the world are old and are not engineered well to prevent contamination of the underlying soil and groundwater by the toxic leachate. The present study examines the potential use of raw zeolite and heated activated zeolite in the reduction of COD, NH3-N, and colour from leachate. Zeolite was activated using different temperatures at 150 °C, 200 °C, and 250 °C for 3 h. General characterization was conducted for raw zeolite and heat-activated zeolite to investigate the influence of temperature on zeolite properties. Batch experiments were conducted at the optimum dosage of zeolite and pH. Results demonstrated that the optimum dosage of raw zeolite was 10 g with 53.1%, 22.5% and 46% reduction of NH3-N, COD, and colour, respectively. The optimum pH for NH3-N was 7 with a percentage removal of 55.8% while better reduction of COD and colour was obtained at pH 4 with a percentage removal of 24.3% and 73.8%, respectively. Also, the optimum temperature tested was at 150 °C, where the optimum dosage using activated zeolite heated at 150 °C was 10 g, resulted in the maximum reduction of NH3-N, COD, and colour of 45.1%, 11.8% and 43.7%, respectively. The optimum dosage of activated zeolite heated at 200 °C and 250 °C, which was 25 g. This indicates that the use of the activated zeolite heated at 150 °C can achieve the optimum removal at a lower cost which is applicable for a larger scale of wastewater treatment. In addition, it was found that the capacity of the zeolite before and after heat activation was 41.30 cmol/kg and 181.90 cmol/kg, respectively. The adsorption isotherm analysis reveals that both Freundlich and Langmuir isotherms were in agreement with experimental data. However, the Freundlich isotherm model was more favourable than Langmuir isotherm to evaluate the adsorption equilibrium of the three pollutants as verified by the high R2 values. Article Highlights: Contamination of landfill leachate poses significant environmental problems since it percolates through the soil and pollutes the groundwater. Raw zeolite and heated activated zeolite in the reduction of COD, NH3-N, and colour from leachate. Batch study experiments were conducted to measure the optimum dosage of zeolite as well as optimum pH of leachate. The activated zeolite can improve the removal of COD, NH3-N, and colour from 24.3%, 55.8%, and 73.8% using raw zeolite to 46.3%, 75.9%, and 91.4%, respectively. The adsorption isotherm analysis reveals that both Freundlich and Langmuir isotherms were in agreement with experimental data. [ABSTRACT FROM AUTHOR]

Leachate is a liquid that is produced when water percolates through solid waste and contain dis-solved or suspended material from various dissolved materials and bio-decomposition process. This study describes the finding of ammoniacal nitrogen and chemical oxygen demand (COD) removal partially replacing the amount of activated carbon. Activated carbon is well known as a good adsorbent for the removal of COD but the cost is relatively very high. However green mussel shell is the most abundant source in the world. Due to its abundance, green mussel is one of the low-cost materials. The combination of both materials is believed to produce inexpensive and suitable composite to treat the leachate. The batch experiment results indicate that the leachate concentration of ammoniacal nitrogen was (148 mg L–1) and that of COD (308 mg L–1). The optimum conditions for removal of ammoniacal nitrogen and COD were determined at 120 min with 200 rpm at pH 7. The optimum ratio of activated carbon and green mussel shell is 2.5:1.5. The values of removal percentage of NH3–N, and COD are 63% and 83%, respectively. The availability of low-cost adsorbent material like green mussel shells in the composite has helped to reduce the treatment cost, along with enhancing the adsorption capacity and is environment friendly. The Langmuir isotherm adsorption model showed a better fit with strong correlation R² = 0.9962 for COD and R² = 0.9918 for NH3–N, respectively, which means that the adsorption of leachate on granular activated carbon-green mussel shell powder, in this study, is homogeneous with the monolayer. [ABSTRACT FROM AUTHOR]

Ammoniacal nitrogen is one of the new parameters incorporated under the Industrial Effluents Regulation in Environmental Quality Act (EQA) starting from January 1st, 2010. Under this regulation, ammoniacal nitrogen limit for industries is regulated at a maximum limit of 10 ppm and 20 ppm depending on whether the facilities located upstream or downstream of the water catchments area. However, the ammoniacal nitrogen limit for semi-conductor companies that started their operation before 2010 has been increased to twice the initial limit due to concerns raised by some of the affected companies. This temporary limit was loosened until January 1st, 2020. The ammoniacal nitrogen is contributed by the use of ammonium hydroxide solution in the wafer fabrication industry, particularly in Chemical Mechanical Polishing (CMP) process. In CMP, the surface of silicon wafers being polished with slurry causing deposition of debris on the wafers. The cleaning process after polishing is termed as a post-CMP step. This paper focuses on the evaluation of post-CMP cleaning efficiency using a SpeedFam IPEC (SFI) AvantGaard™ 776 polisher tool. There are two stages of post-CMP steps named as buffing and scrubbing process. There were studies conducted by past researchers on post-CMP cleaning but none of these studies can be adopted either because the techniques were not economical for production scale compared to wet cleaning process or the chemicals selected are ammonia-based. The objective of the study is to analyse cleaning efficiency at both buffing and scrubbing steps and formulate an alternative solution that does not contain ammonia without compromising cleaning efficiency. It was discovered that the particles on the wafers were effectively removed with efficiency removal of 99% during the buffing step and the special formulated acid named SilTerra Cleaning Solution (SCS) provides comparable capability with ammonium hydroxide on particles and metallic in which both achieved cations and anions removal efficiency higher than 97%. The unique formulation of SCS contains hydrogen peroxide, sulphuric acid, and an additive. The chemical is proprietary of SilTerra by four inventors including the corresponding author. SCS was selected for this evaluation since it contains necessary ingredients to oxidize and dissolve the contaminants. The attempt to skip the application of chemicals during post CMP scrubbing was not promising as anions removal efficiency yielded lower than 95% removal efficiency. [ABSTRACT FROM AUTHOR]

Water is an essential commodity that supports the very existence of life on earth; hence, contamination of ground and water bodies with harmful substances liberated by landfill leachate can seriously impact the environment and well-being of mankind. In this context, explorations in search of economically attractive avenues to treat landfill leachate merit scientific pertinence. A response surface methodology approach based on a three-factor three-level central composite design was applied to compare and optimize the removal of ammoniacal nitrogen (NH3–N) from landfill leachate. In this study, the efficacy of natural zeolite, clinoptilolite, and synthetic zeolite, Sigma 96096, as adsorbents was investigated for parameters, viz. zeolite dosage, particle size, and ratio of leachate to distilled water, respectively. Under optimized conditions, clinoptilolite (2 g/L, 50 μm, and 50%) and Sigma 96096 (4 g/L, 150 μm, and 50%) effectively removed 58.2% and 37.8% of NH3–N, respectively. The equilibrium isotherms of both sorbents for the sorption of NH3–N were also well described by the Freundlich and Langmuir adsorption isotherms, respectively. The study found clinoptilolite was more efficient than Sigma 96096 in removing NH3–N, envisaging its suitability for complementing the current treatment processes to treat landfill leachate. [ABSTRACT FROM AUTHOR]

Wastewater from fertilizer industries is rich in ammoniacal nitrogen and orthophosphates. The present study demonstrates the recovery of nutrients from fertilizer industry effluent in the form of microalgal biomass to produce various bioproducts. The study demonstrates the integration of pilot-scale struvite production from fertilizer industrial wastewater in air-agitated reactor to phycoremediation of residual wastewater. The parameters required for the production of high yield and better quality of struvite were optimized. The microalgal consortium was isolated from anaerobic plant digestate and adapted to tolerate 1000 mg L−1 of NH4-N using synthetic wastewater rich in NH4-N. Pilot-scale struvite production was carried out in the air-agitated reactor (1 m3 capacity) in batch mode and phycoremediation of residual effluent was carried out in tubular photobioreactor (200 L capacity) in fed batch mode. Pilot-scale struvite crystallization produced 60 kg of struvite from 1 m3 of effluent. During struvite precipitation, 2.96% of COD, 68.29% of NH4-N, and 96.38% of PO4-P were recovered. The residual effluent was further phycoremediated by the microalgal consortium. During phycoremediation, 62.68% of COD, 59.21% of NH4-N, and 68.57% of PO4-P were recovered in terms of microalgal biomass. Due to integration, 64.58% of COD, 87.31% of NH4-N, 89.0% of TKN, and 98.79% of PO4-P are recovered. The observed yield (g m−3 effluent) of biomass, lipids, ω-3 fatty acid, and biogas (L m−3 effluent) was 290, 56, 11.2, and 80 L, respectively. In brief, the integration of struvite production and microalgae cultivation can be used as an effective treatment system for fertilizer industry wastewater. [ABSTRACT FROM AUTHOR]

• The content of total nitrogen and ammonia nitrogen in pit mud was rapidly detected. • The characteristic wavelength is extracted by the combination of VCPA-IVSO. • Four prediction models (ELM, SVM, LSSVM, PSO-LSSVM) are established. Total nitrogen and ammonium nitrogen play a pivotal role in preserving the soil's nutrient ecosystem, and rapid determination of their levels in the soil can help improve soil utilization. In this study, hyperspectral imaging technology(HSI) was used to achieve rapid determination of total and ammonia nitrogen in pit mud. Both types of spectral data were pre-processed and the characteristic wavelengths were screened using a combination of variable combined population analysisand iterative variable subset optimization (VCPA-IVSO). Four prediction models (ELM, SVM, LSSVM, PSO-LSSVM) based on characteristic wavelengths and full wavelengths were developed. The results showed that the PSO-LSSVM model with the NIR characteristic wavelengths was more effective in predicting total and ammonia nitrogen in pit sludge (total nitrogen: R c 2 = 0.9999, RMSEC = 0.0014, R p 2 = 0.9892, RMSEP = 0.0111, RPD = 9.6225; ammonia nitrogen: R c 2 = 0.9941, RMSEC = 4.3004, R p 2 = 0.9644, RMSEP = 9.8962, RPD = 5.3).The distribution of total nitrogen and ammonia nitrogen in the region of interest is visually analyzed using the determined best model. These results underscore the potential of HSI as a rapid and non-destructive method for detecting total and ammonia nitrogen levels in pit mud. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of the inclusion of essential oils (EOs) in the diet of beef cattle through a systematic review, followed by a meta-analysis. For the systematic search of scientific articles, a combination of keywords such as, "essential oils", "beef cattle," and "steers," was used in three databases: Scopus, PubMed, and Web of Science. After screening and selection of the articles, 14 studies were selected. The characteristics evaluated in the selected articles were, dry matter intake (DMI), average daily gain (ADG), and the gain:feed ratio (G:F ratio), in addition to the ruminal fermentation parameters, such as, pH, ammoniacal nitrogen (NH 3 -N), total volatile fatty acids (VFAs), acetate:propionate ratio (A:P), and methane (CH 4). The meta-analysis was conducted using the R statistical program. The inclusion of EOs as feed additives in the diet of beef cattle increased the DMI (MD = 0.2862, P = 0.0077), the ADG (MD = 0.1148, P = 0.0180), the G:F ratio (MD = 0.0060, P = < 0.0001), the molar proportion of propionate (MD = 1.6929, P = 0.0045), butyrate (MD = 0.4257, P = 0.0135), isobutyrate (MD = 0.3409, P = 0.0384), valerate (MD = 0.0761, P = 0.02730), reduced N-NH 3 concentrations (MD = −1.5787, P = 0.0004), the acetate molar proportion (MD = −2.0688, P = 0.0104), and the A:P ratio (MD = - 0.3185, P = 0.0007). The result of the meta-regression analyses suggested that the covariates of the experimental design and experimental period were the main covariates that influenced (P < 0.05) the DMI. Moreover, the experimental design, essential oil type, and the experimental period had an effect (P ≤ 0.05) on the ADG. The response variables related to the parameters of rumen fermentation were influenced by the covariates' experimental design and breed. The subgroup analyses showed that the variables DMI, ADG, propionate, and isobutyrate were influenced (P ≤ 0.05) by the experimental design, experimental period, dose, breed, and type of essential oil used. Thus, we conclude that the addition of EOs in the diet of beef cattle improves the performance of the animals, as it increases the DMI and ADG, reduces the concentrations of N-NH 3 , and increases the molar proportion of propionate, thus improving the A:P ratio. However, additional studies are needed to better understand the mechanism of action of EOs, especially on ruminal microorganisms and their effects on the parameters of ruminal fermentation. • The meta-analysis indicated the potential use of EOs in the feed of beef cattle. • The addition of EOs improved feed intake and animal performance. • Dietary supplementation of EOs reduced ruminal NH 3 -N concentrations. • Propionate proportions increased with the addition of EOs, resulting reduced A:P ratio. [ABSTRACT FROM AUTHOR]

Brackish water shrimp aquaculture activities often result in organic waste from excess of unconsumed foodstuff and biological waste from shrimp biological waste. The high organic contents increase the levels of ammonia, which is toxic to shrimp and many other aqua lives. One of the most widely used organic material biodegradation system as biofilters, biofilm has not yet seen many uses in shrimp aquafarm waste management. This study aims to isolate and screen biofilm-forming primary bacteria with abilities to degrade ammoniacal nitrogen compounds. The processes involved in this study are location survey, wooden and fiber panel installation, planting of panel in the ponds, isolation of bacteria by dispersion method, purification of primary bacteria by scratch method. Ammoniacal nitrogen degradation test was performed by Microwell Plate Chromatogram Assay and UV-Vis Spectrophotometry. The analysis of the bacteria isolates found 66 primary bacteria with biofilm formation abilities. Based on qualitative analysis, 20 isolates displayed potential in degrading ammoniacal nitrogen compound and 7 isolates showed low (

Chemical composition and ruminal digestion parameters were mea- sured in the silage of the whole corn plant (Zea mays L.) mixed with mulberry foliage (Morus alba L.) in ratio of 100:0, 80:20, 60:40, 40:60, 20:80 and 00:100% of fresh forage weight, respectively. The 40:60 ratio of corn: mulberry increased crude protein content (CP = 14.28%) and decreased hemicellulose (12.15%), neutral (NDF = 28.00%) and acidic (ADF = 15.85%) detergent fiber, compared to 100: 0% ratio, respectively, which led to a 21.3% increase in in vitro dry matter digestibility (IVDMD). Also ammoniacal nitrogen 7.40% (NH3-N/total N) was higher in the ratio 40:60%, with pH of 4.19 which is normal for silages, which translates the buffer activity correct of ammonia and its importance for silage fermentation stability. The correlation (r = 0.61, p < 0.001) indicated that at higher CP content, higher is IVDMD and hemicellulose (r = -0.99), ADF (r = -0.98) and NDF (r = -0.98) indicated that these fibrous compounds decreased IVDMD (p < 0.001). The regression showed that the increase in content CP (0.555%, p < 0.01) and IVDMD (0.3391%, p < 0.001) with the decrease of NDF (-0.3526%), ADF (-0.1623%) and hemicellulose (-0.1903%) (p < 0.001) in mixed mini silos, was attributed to mulberry foliage addition. It is concluded that the contribution of dry matter and nitrogen of mulberry, decreased the fiber content and increased digestibility parameters of silage when it is elaborated in ratio of 40:60 corn and mulberry, respectively.

This study examined rumen fermentation, histological, blood, and urinary characteristics as well as ammoniacal nitrogen concentration, pH, nitrogen balance, and microbial protein in lamb fed diets containing spineless cactus as the sole roughage source plus levels of wheat bran (WB) in comparison with a control diet based on spineless cactus and buffelgrass. Twenty-eight uncastrated, crossbreed lambs with an average initial weight of 22.6 ± 2.37 kg were used in the experiment. The treatments consisted of a standard diet (control) containing buffelgrass and spineless cactus and three diets containing cactus as the only roughage source plus varied concentrations of WB (30, 37, and 44%, on a dry matter basis). Results were evaluated by analysis of variance, and contrasts were applied at the 5% probability level for mean comparison. Rumen villus height and width were greater and musculature was lower in the lamb fed diets containing 37% and 44% WB compared with those fed control diet. In the intestine, the crypts were smaller in the animals which consumed the diets with 30, 44, and 37% WB. All WB levels resulted in lower nitrogen intake and retention. Microbial protein concentration, microbial protein efficiency, microbial nitrogen, urea, and glucose were not significantly affected. Feeding lamb with diets containing levels of wheat bran, with cactus as the only roughage source, does not negatively affect their ruminal-fermentation, blood, and urinary characteristics; ammoniacal nitrogen concentration; pH; or microbial protein. However, nitrogen balance and ruminal and intestinal morphometric characteristics are impaired. [ABSTRACT FROM AUTHOR]

Eutrophication is a serious environmental issue that needs urgent concern. There is necessity to treat wastewater with high ammoniacal nitrogen (AN) concentration to the permissible standard limit to protect the aquatic ecosystem. This study investigated the optimum condition for AN removal from wastewater using Eichhornia crassipes-based phytoremediation process. Face-centered central composite design (CCD) was employed as the experimental design, in which four operational variables including pH (4–10), retention time (2–14 days), macrophyte density (5–30 g/L) and salinity (0–5 g NaCl/L) were involved in the study, while five responses were investigated, namely AN removal efficiency (Y1), fresh biomass growth (Y2), COD (Y3), BOD (Y4) and TSS (Y5). AN removal was the main focus in this study. Through numerical optimization, the highest AN removal efficiency of 77.48% (initial AN concentration = 40 mg/L) was obtained at the following optimum condition: pH 8.51, retention time of 8.47 days, macrophyte density of 21.39 g/L and salinity of 0 g NaCl/L. The values predicted from the models agreed satisfactorily with the experimental values, which implied that response surface methodology was reliable and practical for experimental design developed using optimization of the phytoremediation process. The validation experiment using real semiconductor effluent further supported the high potential of the E. crassipes-based phytoremediation system to remove AN and other organic pollutants in this industrial effluent under optimal condition. [ABSTRACT FROM AUTHOR]

The untreated wastewater from the dye industry having high ammoniacal nitrogen and chemical oxygen demand (COD) significantly pollutes the receiving water, such as a river, having major ill implications on the aquatic environment. The present study is undertaken to address this problem. It investigates the effectiveness of Fenton reagent in simultaneous treatment (removal) of ammoniacal nitrogen and COD present in the wastewater by varying the parameters like pH, concentration of Fe 2+ and H2O2 and their molar ratio. The reaction time for all the experiments was kept 60 min. The experimental analysis in terms of calculating the residual % of ammoniacal nitrogen and COD revealed that the maximum reduction occurred at pH 3. At this pH, further set of experiments were performed by varying the molar doses of Fe2+/H2O2 as 1:1, 3:3 and 5:5, and the results reveal that the maximum reduction in both ammoniacal nitrogen and COD happens at molar dose of 3:3. To understand the effect of the concentration of Fe2+ and H2O2 on the respective removal efficiency, set of experiments were performed by taking the molar ratio of Fe2+/H2O2 as 2:1, 3:1, 5:1, 1:2, 1:3 and 1:5. The experimental analysis reveals that the maximum reduction happened at molar ratio 1:3. Fenton process can mineralize the pollutants up to 75.8% and 78.6% for ammoniacal nitrogen and COD removal. The findings of the study would be of great use for planning and optimizing the wastewater treatment facility for the dye intermediate industry. [ABSTRACT FROM AUTHOR]

This study revealed the relationship between the presence of calcium impurities and ammoniacal nitrogen concentration upon crystallization of struvite. The research hypothesis was that the presence of both calcium and high concentrations of ammoniacal nitrogen (328–1000 mg/L) in waste activated sludge may influence the struvite quality and acid stability. Hence, we studied the impact of Ca:Mg ratio upon morphology, particle size, purity and dissolution of struvite, in the presence of varying levels of excess ammoniacal nitrogen. X-ray diffraction revealed that up to 31.4% amorphous material was made which was assigned to hydroxyapatite. Increasing the ammoniacal nitrogen concentration and elevation of the Mg:Ca ratio maximized the presence of struvite. Struvite particle size was also increased by ammoniacal nitrogen as was twinning of the crystals. Tests with dilute solutions of organic acid revealed the sensitivity of struvite dissolution to the physical characteristics of the struvite. Smaller particles (21.2 μm) dissolved at higher rates than larger particles (35.86 μm). However, struvite dissolved rapidly as the pH was further reduced irrespective of the physical characteristics. Therefore, addition of struvite to low pH soils was not viewed as beneficial in terms of controlled nutrient release. Overall, this study revealed that waste activated sludge effluent with high ammoniacal nitrogen was prospective for synthesis of high quality struvite material. Unlabelled Image [ABSTRACT FROM AUTHOR]

Phosphorus is one of the most important mineral elements for plant growth and development, and different nitrogen forms can regulate phosphorus uptake. As is well-known that plant plasma membrane (PM) H+-ATPase plays an important role in nutrition uptake, it may also relate to the different nitrogen-modulated phosphorus uptake. In our study, PM H+-ATPase in tea roots were isolated by two-phase partitioning in aqueous dextranT-500 and polyethylene glycol, and the effect of different nitrogen forms on phosphorus uptake and the characteristic parameters of PM H+-ATPase in tea roots were examined by using non-invasive micro-test technique and Western-blot. It was found that ammonium significantly improved the phosphorus accumulation in tea plants as compared with nitrate nutrition. In addition, less depolarized PM potentials, higher net H+ flux, PM H+-ATPase activities and protein levels were found under ammonium treatment than those under nitrate nutrition treatment. Furthermore, vanadate (the PM H+-ATPase inhibitor) significantly decreased phosphorus accumulation in tea plants under ammonium and nitrate nutrition treatments, which further suggests that PM H+-ATPase may be involved in phosphorus accumulation in tea plants regulated by different nitrogen forms. [ABSTRACT FROM AUTHOR]

The present study has the objective of optimizing operational conditions of an aerated reactor applied to the removal of ammoniacal nitrogen from wastewater resulting from the production of cassava starch. An aerated reactor with a usable volume of 4 L and aeration control by rotameter was used. The airflow and cycle time parameters were controlled and their effects on the removal of ammoniacal nitrogen and the conversion to nitrate were evaluated. The highest ammoniacal nitrogen removal, of 96.62%, occurred under conditions of 24 h and 0.15 L min−1 Lreactor−1. The highest nitrate conversion, of 24.81%, occurred under conditions of 40.92 h and 0.15 L min−1 Lreactor−1. The remaining value of ammoniacal nitrogen was converted primarily into nitrite, energy, hydrogen and water. The optimal operational values of the aerated reactor are 29.25 h and 0.22 L min−1 Lreactor−1. The mathematical models representative of the process satisfactorily describe ammoniacal nitrogen removal efficiency and nitrate conversion, presenting errors of 2.87% and 3.70%, respectively. [ABSTRACT FROM AUTHOR]

• Coagulation-flocculation greatly reduced turbidity to ease the photocatalytic process. • Aeration enhanced melanoidins removal during photocatalytic process. • pH played a crucial role in photocatalytic treatment of molasses wastewater. • ZnO and TiO 2 achieved mineralization efficiency of 60.2 % and 58.5 %, respectively. • Oxidation of NH 3 N occurred in photocatalytic treatment of molasses wastewater. The brown color of molasses wastewater is due to the presence of melanoidins which are toxic to human health and environment. In this study, combination of coagulation-flocculation process with UVA-photocatalytic degradation of raw and diluted molasses wastewater in the presence of zinc oxide (ZnO) and titanium dioxide (TiO 2) as photocatalyst was investigated. The effect of various operating parameters, such as light irradiation, aeration, catalyst dosage and pH of molasses wastewater on the photocatalytic degradation process was examined. The pre-treated diluted molasses wastewater (2 DF) showed greater performance compared to pre-treated raw for both photocatalysts due to high penetration of light into the wastewater. The formation of •OH enhanced color intensity reduction rate of pre-treated raw and 2 DF molasses wastewater in the presence of light irradiation and aeration. The color removal efficiency of pre-treated raw and 2 DF molasses wastewater was better in alkaline medium (pH 10) when ZnO used as photocatalyst, meanwhile it achieved higher removal efficiency in acidic medium (pH 4) when TiO 2 was used as photocatalyst. The mineralization and oxidation of ammoniacal-nitrogen of molasses wastewater showed enhanced performance in photocatalytic treatment. [Display omitted] [ABSTRACT FROM AUTHOR]