Eutrophic Wastewater Research Articles

Reticulated lanthanum (La) carbonate-carbon composite for efficient phosphorus removal from eutrophic wastewater

Reticulated lanthanum (La) carbonate-carbon composite for efficient phosphorus removal from eutrophic wastewater

Lanthanum ion modification of aminated cyclomatrix polyphosphazene-coated porous carbon nanosheets for rapid, efficient and selective removal of phosphate

Phosphate removal has been the top priority in eutrophic wastewater treatment. Herein we reported a fast, efficient and selective adsorbent, PCNs@PCP-La, for phosphate removal from an aqueous medium. The adsorbent was fabricated via two steps: (1) synthesis of PCNs@PCP composite through in situ polymerization of hexachlorocyclotriphosphazene and polyethyleneimine on the porous carbon nanosheets; and (2) lanthanum ion (La3+) modification of PCNs@PCP via an impregnation process to create PCNs@PCP-La hybrid. Multiple characterizations showed that the atomically dispersed La3+ ions could be facilely chelated with nitrogen-rich cyclomatrix polyphosphazene framework, significantly improving the application efficiency of La3+ ions as active adsorption sites. Comparative tests confirmed that PCNs@PCP-La had a high phosphate uptake capacity of up to 121.2 mg P g−1 (pH = 4.0) at 298 K and performed well even in a wide pH range (3.0–9.0). Also, PCNs@PCP-La showed a particularly short saturated adsorption time (5 min), indicating a fast adsorption kinetic process. Meanwhile, PCNs@PCP-La presented a superior adsorption selectivity for phosphate under interference with coexisting anions/cation and humic acid, and owned an attractive reusability (after 5th cycles, 85% capacity retention). The plausible adsorption mechanism can be ascribed to electrostatic attraction, inner-sphere complexation, and the formation of LaPO4·0.5H2O precipitates between adsorbent and adsorbate.

Effective Purification of Eutrophic Wastewater from the Beverage Industry by Microbubbles

Beverage industries often discharge large amounts of organic matter with their wastewater. Purification of the effluent is their obligation, but it is nontrivial. Among wastewater components, removal of dissolved organic matter often requires much effort. Therefore, a special effective technique must be considered. Microbubbles (1–100 μm) have several special properties of relevance to wastewater treatment. In this study, the effectiveness of microbubbles for treating and purifying beverage wastewater was evaluated. Orange juice, lactic acid drink, and milk were used as model substrates of dissolved organic matter, and degradation experiments were carried out. Rates of air supply by microbubbles were 0.05% (air/wastewater) min−1. Results indicated that the total organic carbon (TOC) in an experimental vessel containing milk (high nitrogen content) decreased by 93.1% from 11.0 to 0.76 g during a 10-day incubation. The TOC of lactic acid drink (least nitrogen content) decreased by 66.3%, from 15.6 to 5.26 g, and the TOC of orange juice (medium nitrogen content) decreased by 82.7%, from 14.8 to 2.55 g. Large amounts of particulate organic matter floated on the water surface in the milk with microbubbles and were removed easily, while almost no floating materials were observed in the orange juice and lactic acid drink. In contrast, in the macrobubble treatment (diameter 0.1 to 2 mm), only 37.0% of TOC in the milk was removed. Whereas the macrobubble treatments were anaerobic throughout the incubations, the microbubble treatments returned to aerobic conditions quickly, and brought 10 times greater bacterial abundances (>108 cells mL−1). These results suggest that microbubbles are much superior to macrobubbles in supplying oxygen and accelerating the growth of aerobic bacteria, and that wastewater containing more nitrogenous compounds was purified more effectively than that with less nitrogen by microbial degradation and floating separation.

Remediation of algal cells, PO43−, and NO3− from eutrophic wastewater using Echinodorus cordifolius in zigzag-horizontal subsurface constructed wetlands

The pollutant removal efficiency of traditionally constructed wetlands (CWs) is often limited due to low interaction time between wastewater and the CW matrix (plants, microbes, and substrates). A zigzag-horizontal subsurface flow constructed wetland with effluent recirculation (Z-HSSF + ER) was developed to improve removal efficiency. Echinodorus cordifolius plants were used in this study. The efficiency of the systems was evaluated using eutrophic wastewater. The results showed that the developed systems exhibited the high removal efficiency of algal cells, PO43−, and NO3− (97%, 70%, and 100%, respectively), within 5 days. Algal cells were removed by the interception mechanism of gravel and zigzag baffles. PO43− and NO3− in the eutrophic wastewater was mainly removed by E. cordifolius including rhizobacteria and other microorganisms. The long flow pathway created by the installation of zigzag baffles combined with effluent recirculation provides high dissolved oxygen (DO) in the systems and increases the interaction time between wastewater and the CW matrix, thus improving the pollutant removal efficiency of CWs.

Purifying Eutrophic Wastewater from Geese Farm with Plant Floating Bed in Winter

Purifying Eutrophic Wastewater from Geese Farm with Plant Floating Bed in Winter

Large-Scale Green Liver System for Sustainable Purification of Aquacultural Wastewater: Construction and Case Study in a Semiarid Area of Brazil (Itacuruba, Pernambuco) Using the Naturally Occurring Cyanotoxin Microcystin as Efficiency Indicator.

The aquaculture industry in Brazil has grown immensely resulting in the production of inefficiently discarded wastewater, which causes adverse effects on the aquatic ecosystem. The efficient treatment of aquaculture wastewater is vital in reaching a sustainable and ecological way of fish farming. Bioremediation in the form of the Green Liver System employing macrophytes was considered as wastewater treatment for a tilapia farm, COOPVALE, in Itacuruba, Brazil, based on previously demonstrated success. A large-scale system was constructed, and the macrophytes Azolla caroliniana, Egeria densa, Myriophyllum aquaticum, and Eichhornia crassipes were selected for phytoremediation. As cyanobacterial blooms persisted in the eutrophic wastewater, two microcystin congeners (MC-LR and -RR) were used as indicator contaminants for system efficiency and monitored by liquid-chromatography–tandem-mass-spectrometry. Two trial studies were conducted to decide on the final macrophyte selection and layout of the Green Liver System. In the first trial, 58% MC-LR and 66% MC-RR were removed and up to 32% MC-LR and 100% MC-RR were removed in the second trial. Additional risks that were overcome included animals grazing on the macrophytes and tilapia were spilling over from the hatchery. The implementation of the Green Liver System significantly contributed to the bioremediation of contaminants from the fish farm.

Removal of Total Nitrogen and Phosphorus Using Single or Combinations of Aquatic Plants.

Phytoremediation is a potentially suitable technology for taking up large amounts of N and P during plant growth and the removal of plant material, thereby avoiding eutrophication. We compared the capacity of nine different aquatic plant species for removing total P (TP), total N (TN), and NH4+-N from raw domestic sewage wastewater collected from a living area located in Guangzhou city, China, and different concentrations of artificial wastewater. The experiments were performed in two stages, namely screening and modification. In the screening stage, four plant species were identified from the nine grown in raw domestic sewage water for 36 days. In the modification stage, the TN and TP removal ability of different plant combinations were determined in artificial wastewater at different N/P concentrations. After having been grown in monocultures for 46 days, Ipomoea aquatica (90.6% and 8.8%) and Salvinia natans (67.3% and 14.2%) obtained the highest TP removal efficiency in lightly and highly polluted wastewater, respectively. The combination of S. natans and Eleocharis plantagineiformis effectively removed TP and TN from lightly polluted water, suggesting that this combination is suitable for phytoremediation of eutrophic wastewater.

Modified mussel shell powder for microalgae immobilization to remove N and P from eutrophic wastewater

In this work, calcined mussel shell powder (CMSP) was activated by K2CO3 (K-CMSP), and this porous K-CMSP surface was modified by L-arginine (L-ARG) to render porous biomass a positively charged surface, which was innovatively utilized as a carrier to immobilize microalgae by adsorption via electrostatic interactions. The pore and the surface structures of CMSP and K-CMSP were characterized by XRD, FTIR, BET and SEM. The surface morphology of immobilized microalgae was visualized via using inverted optical microscope and SEM. It was found that microalgae could survive for 60 days, and the loss rate of chlorophyll-a preserved at −24 °C was the lowest, 44.73%. The microalgae could revive to normal growth level within 10 days and the cell content of microalgae was the highest at 25 °C, 2.8022 × 106 cell/mL. At 25 °C, the highest removal rate of N and P was obtained about 95.0% and 88.63%, respectively.

A critical review of clay-based composites with enhanced adsorption performance for metal and organic pollutants.

Adsorption techniques offer unique advantages owing to the use of synthetic (e.g., nanosized metal oxides and polymer-functionalized nanocomposites) and natural (e.g., clay and biochar) materials for pollutant removal. Although the most widely used adsorbent is activated carbon, extensive studies have highlighted the promising potential of modified clay minerals and biochar for removing heavy metal and organic pollutants from industrial, drinking, and eutrophic wastewater, due to their low cost and easy accessibility. However, clay modification using acids, calcination, polymers, or surfactants exhibits relatively low absorption/regeneration ability towards antibiotics, aromatics, and various dyes. The coexistence of numerous contaminants in industrial wastewater inhibited the performance of adsorbents, which accelerated the development of novel modified clay composites such as clay-biochar, organo-bentonite/sodium alginate beads, and enhanced biochar. This review summarizes recent studies and absorption mechanisms concerning clay composites based on various modification methods and component materials. The comparison of clay composites used for the removal of organic and inorganic contaminants provides valuable insight into real wastewater treatment. Knowledge gaps, uncertainties, and future challenges involved in the fabrication and regeneration of modified clay composites are also identified.

A strategy of high-efficient nitrogen removal by an ammonia-oxidizing bacterium consortium

An ammonia-oxidizing bacterium consortium showed approximately 100% removal of NH4+-N with an initial concentration of 262.28 ± 8.21 mg·L−1 within 10 days, and only 16.54 ± 0.52% of NH4+-N was converted to NO2−-N in this study. The consortium removed ammonium by heterotrophic nitrification and aerobic denitrification (HNAD) without N2O emission. The activity of AOB was not affected by low concentrations of FA or FNA, but completely inhibited by 0.04 mg HNO2·L−1. In a bioaugmentation treatment of eutrophic wastewater using the consortium, the removal efficiency of NH4+-N reached 90.85 ± 0.8% and 77.88 ± 1.86% at initial concentrations of 1.80 ± 0.04 mg·L−1 and 40.31 ± 0.57 mg·L−1, respectively, and the dissolved oxygen level had a significant impact on the consortium activity. No significant changes in the bacterial community structure were observed after the consortium addition, and local functional bacteria were enriched by aeration and contributed to ammonium nitrogen removal with AOB.

Treatment of Eutrophic Water and Wastewater from Valsequillo Reservoir, Puebla, Mexico by Means of Ozonation: A Multiparameter Approach

The present work aims to elucidate the possibility of injecting ozone into surface waters combined with urban wastewaters in order to improve the water quality of the High Atoyac Sub-basin (HAS) in Central Mexico. For this purpose, twenty physicochemical parameters, eight heavy metals, seven organic compounds, and one biological indicator were assessed in water from different sites of the studied area (the Alseseca River, the Atoyac River and the Valsequillo Reservoir). Results demonstrated that O3 injection led to the decrease of the aromatic fraction of organic molecules since the Spectral Absorption Coefficient at 254 nanometers (SAC254) reduction was found to be 31.7% in the Valsequillo Reservoir water samples. Maximum Chemical Oxygen Demand (COD) removal was observed to be 60.2% from the Alseseca River with a 0.26 mg O3/mg initial COD dose. Among all the phthalates studied in the present work, Di(2-ethylhexyl) phthalate (DEHP) exhibited the highest concentration (5.8 μg/L in the Atoyac River). Treatment with O3 was not effective in eliminating fecal coliforms (FC) in waters that host high organic matter (OM) loads as opposed to waters with low OM. After the injection of 4.7 mg O3/mg COD in the VO3-AT water sample, a 90% removal of Iron (Fe) and Aluminum (Al) was registered; while Manganese (Mn), Nickel (Ni), Zinc (Zn), and Cooper (Cu) showed a 73%, 67%, 81%, and 80% removal, respectively; Chromium (Cr) registered the highest removal (~100%). The present work demonstrated that while finding a suitable O3 dose to improve the quality of water in the HAS, the 5-days Biochemical Oxygen Demand (BOD5)/COD ratio (i.e., biodegradability) is more important than the overall OM removal percentage proving that O3 injection is a feasible process for the treatment of eutrophic waters from HAS.

Enhanced phosphate removal from wastewater by using in situ generated fresh trivalent Fe composition through the interaction of Fe(II) on CaCO3

Excessive existences of nutrients such as phosphate in the aqueous environment remain as a heavy concern although many researches have been reported for dealing with their removal. Based on the understanding toward the interactions of Fe compounds with phosphate and carbonate from many available researches, we designed a very simple and efficient approach for phosphate removal by using in situ generated fresh trivalent Fe composition through the interaction of Fe(II) as FeSO4 on CaCO3. Addition and agitation of Fe(II) and CaCO3 simultaneously to phosphate solution allowed an amorphous Fe(III)-P or Ca-Fe(III)-P precipitation, with a phosphate removal rate close to 100%, to reduce the residual phosphorus concentration less than 0.03 mg/L from 100 mg/L, reaching the discharge limit, even with the addition amounts of CaCO3 as low as a stoichiometric ratio of CaCO3/PO43− at 0.9 and ratio of Fe(II)/PO43− at 1.5, and the percent of P2O5 in the precipitate was as high as 19.4% enough as phosphate source for fertilizer production. Different from the alkaline process with enough OH− group, the slow hydrolysis of CaCO3 resulting in low concentration of OH− group for the formation of Fe(OH)2, which was oxidized soon by air into trivalent Fe, achieved a continuous generation of fresh ferric composition for phosphate precipitation and could avoid its rapid formation and subsequent transformation into stable FeOOH of large particle size to lose the activity. These results based on the synergistic effect of using CaCO3 and Fe(II) together may have applications in the treatment of eutrophic wastewater through a process with many advantages of easy operation and low-cost besides the high removal efficiency with phosphate percentage inside the precipitate high enough to serve for fertilizer production.

Aquatic and terrestrial weed mediated synthesis of iron nanoparticles for possible application in wastewater remediation

The present study was aimed to utilize the aquatic and terrestrial weeds such as Eichhornia crassipes, Lantana camara and Mimosa pudica for the synthesis of iron nanoparticles. The formation of iron nanoparticles was characterized using UV–vis spectroscopy, Dynamic light scattering, Field emission scanning electron microscopy, and Energy dispersive x-ray analysis, Transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. The UV–vis spectra showed a disappearance of the peak in case of synthesized iron nanoparticles which confirmed the formation of iron nanoparticles. The phase analysis using X-ray diffraction revealed the amorphous nature of iron nanoparticles. The dynamic light scattering confirmed 40–60 nm, 50–80 nm and 65–230 nm size distribution for Eichhornia crassipes, Lantana camara and Mimosa pudica synthesized iron nanoparticles respectively. The Transmission electron microscopy micrographs indicated the prominent capping layer of polyphenols around the nanoparticles. The reactivity of synthesized iron nanoparticles for nitrate and phosphate removal was also evaluated on real collected samples of dairy wastewater. A control experiment exhibited that chemically synthesized iron nanoparticles removed 85.27% of nitrate, while Eichhornia crassipes, Lantana camara and Mimosa pudica mediated iron nanoparticles showed 74.52%, 71.12% and 65.23% of nitrate removal respectively. The nitrate was more efficiently removed than the phosphate. The stability of extract based nanoparticles was higher than the chemically synthesized iron nanoparticles. The findings of the present work revealed that weeds which are treated as waste and worthless have very high potential to synthesize iron nanoparticles. Further, these as prepared iron nanoparticles can be applied in treating nitrate and phosphate pollutants present in eutrophic wastewater.

Biomass yield, oil productivity and fatty acid profile of Chlorella lobophora cultivated in diverse eutrophic wastewaters

Abstract Experimental trial of biomass yield, oil productivity and fatty acid profile of Chlorella lobophora in natural eutrophic wastewaters from three different sources was carried out using Bold's Basal Medium as the control. Eutrophication of water is a serious environment issue in agricultural as well as in many industrial zones in the world. But algal biomass production remains the most cost-effective and sustainable means to deal with eutrophic wastewater. Algal culture is the potential method of combining wastewater treatment, nutrient removal, resource recovery and simultaneous yield of biomass and bio-oils. Algal biomass has nutraceutical and biofuel applications. The major objective of the present experimentation was to test the suitability of different eutrophic wastewaters towards understanding the optimum requirements of microalgae for best biomass and oil yield. Influence of variations in nutrient composition of the wastewaters on chemical profile of the oil are also analyzed. Different water quality parameters were found significantly correlated to biomass characteristics of the alga. Oil productivity as well as chemical profile of the oil also exhibited interrelationships to water quality parameters. The oil of algal biomass taken from all kinds of wastewater sources is found suitable for biodiesel through transesterification. Overall, the method stands as model for preliminary screening of algae for economic utilization of wastewaters towards attaining high biomass yield with desired oil quality, especially for biodiesel production.

The physiological and biochemical mechanism of nitrate-nitrogen removal by water hyacinth from agriculture eutrophic wastewater

Large amount of agriculturl wastewater containing high level nitrate-nitrogen (NO3 --N) is produced from modern intensive agricultural production management due to the excessive use of chemical fertilizers and livestock scale farming. The hydroponic experiment of water hyacinth was conducted for analyzing the content of NO3 --N, soluble sugar content, N-transported the amino acid content and growth change in water hyacinth to explore its purification ability to remove NO3 --N from agriculture eutrophic wastewater and physiological and biochemical mechanism of this plant to remove NO3 --N. The results showed that the water hyacinth could effectively utilize the NO3 --N from agriculture eutrophic wastewater. Compared with the control, the contents of NO3 -change to NO3 --N in the root, leaf petiole and leaf blade of water hyacinth after treatment in the wastewater for a week was significantly higher than that in the control plants treated with tap water, and also the biomass of water hyacinth increased significantly, indicating that the accumulation of biomass due to the rapid growth of water hyacinth could transfer some amount of NO3 --N.13C-NMR analysis confirmed that water hyacinth would convert the part nitrogen absorbed from agriculture eutrophic wastewater to ammonia nitrogen, which increased the content of aspartic acid and glutamic acid, decreased the content of soluble sugar, sucrose and fructose and the content of N-storaged asparagine and glutamine, lead to enhance the synthesis of plant amino acids and promote the growth of plants. These results indicate that the nitrate in agriculture eutrophic wastewater can be utilized by water hyacinth as nitrogen nutrition, and can promote plant growth by using soluble sugar and amide to synthesis amino acids and protein.

Purification Efficiency of Compound Aquatic Plants for the Eutrophic Water Body

In order to study combination effect of aquatic plants for the purification of eutrophic wastewater, research was carried out in greenhouse with water hyacinth (Eichhornia crassipes), hornwort (Ceratophyllum demersumL) an water milfoil (Myriophyllum verticillatum L). In the treatment of water hyacinth + water milfoil , the removal efficiency of ammonium nitrogen (NH4+-N), nitrite nitrogen (NO3--N) , total nitrogen (TN), total phosphorus (TP) and COD was 74.7%, 61.7%, 65.6%, 73.8% and 50.8% respectively. And that of water hyacinth + hornwort was 79.0%, 52.6%, 67.5%, 46.2% and 56.9%. The combination of different aquatic plants have better removal efficiency than single species. Water milfoil showed good removal ability for the eutrophication pollutants, such as nitrogen and phosphorus, while hornwort was good at the purification of COD.

Green synthesized iron nanoparticles by green tea and eucalyptus leaves extracts used for removal of nitrate in aqueous solution

Since water pollution associated with high concentrations of nitrate poses serious threats to aquatic ecosystems and can eventually lead to eutrophication, the removal of nitrate, particularly in a large scale context is still a challenge. To address it, this study proposed that iron nanoparticles (Fe NPs) synthesized by green tea (GT-Fe) and eucalyptus leaves (EL-Fe) extracts, which regarded as cleaner productions can be used for the efficient removal of nitrate. Scanning electron microscopy (SEM) and X-ray energy-dispersive spectrometer (EDS) confirmed the successful synthesis of spheroidal iron nanoparticles. Meanwhile, X-ray diffraction (XRD) and Fourier Transform Infrared spectrometer (FTIR) indicated the formation of Fe0-iron oxide core-shell NPs with polyphenols as a capping/stabilizing agent. Batch experiment showed that 59.7% and 41.4% of nitrate was removed by GT-Fe and EL-Fe NPs, compared to the 87.6% and 11.7% that was removed using zero-valent iron nanoparticles (nZVI) and Fe3O4 nanoparticles, respectively. Nevertheless, reactivity of nZVI decreased 2.1-fold after being aged in air for two months, whilst GT-Fe and EL-Fe NPs almost remain the same. Additionally, the kinetics study indicated that the nitrate removal process better fitted to the pseudo-second-order adsorption model, where the qe was 13.06 mg/g for GT-Fe and 9.698 mg/g for EL-Fe NPs. Based above, a removal mechanism dominated by adsorption and co-precipitation process with subsequently reduction was proposed. Finally, applications of these as-prepared green Fe NPs in swine wastewater demonstrated a promising environmental pollution management option for large scale eutrophic wastewater treatment.

Green synthesis of Fe nanoparticles using eucalyptus leaf extracts for treatment of eutrophic wastewater

Iron nanoparticles were firstly synthesized through a one-step room-temperature biosynthetic route using eucalyptus leaf extracts (EL-Fe NPs). Scanning electron microscopy (SEM) and X-ray energy-dispersive spectrometer (EDS) confirmed the successful synthesis of the spheroidal iron nanoparticles. Furthermore, X-ray diffraction (XRD) and Fourier Transform Infrared spectrometer (FTIR) indicated that some polyphenols are bound to the surfaces of EL-Fe NPs as a capping/stabilizing agent. Reactivity of EL-Fe NPs was evaluated for the treatment of swine wastewater and results indicated that 71.7% of total N and 84.5% of COD were removed, respectively. This demonstrated the tremendous potential of EL-Fe NPs for in situ remediation of eutrophic wastewater.

The Research of Eutrophic Wastewater Treatment Process Design

The treatment object of this paper is eutrophic organic wastewater, put forth effort to research a processing mode which is low energy consumption, high efficiency, construction and operation cost less .Due to the eutrophic wastewater not only contains a lot of organic matter ,but also contains rich nitrogen and phosphorus ,the effect not beautiful when using general anaerobic treatment .Based on the step anaerobic reaction and step aerobic reaction processing way, through the experiment proved that this method not only can effectively remove organic matter in water pollution, but also can produce methane to use .

Effects of Carbon,Nitrogen,and Phosphorus Concentration in Eutrophic Wastewater on Total Lipids and Total Hydrocarbons of Botryococcus braunii

Eutrophication wastewater from twice filtered fishponds was used as the culture medium,into which carbon,nitrogen,and phosphorus were added.The influences of different concentrations of inorganic carbon,total nitrogen,and total phosphorus of sewage on biomass,li-pid content,and hydrocarbon content of Botryococcus braunii were studied.The following results were reported:(1) Using NaHCO3 as the carbon source,the biomass and lipid content of B.braunii were the highest at the inorganic carbon concentration of 5-10 mg/L,while the highest hydrocarbon content was at the inorganic carbon concentration of 15 mg/L.(2) Using KNO3 as the nitrogen source,the biomass of B.braunii was the highest at the total nitrogen concentration of 15 mg/L;the highest lipid content was at the total nitrogen concentration of 2 mg/L;the highest hydrocarbon content was at the total nitrogen concentration of 20 mg/L.(3) Using KH2PO4 as the phosphorus source,the biomass of B.braunii was the highest at a total phosphate concentration of 2 mg/L while the highest lipid content and the highest hydrocarbon content were at a total phosphorus concentration of 1.5 mg/L.