TP Concentrations Research Articles

Utility of a macroinvertebrate-based multimetric index in subtropical shallow lakes

Abstract Benthic macroinvertebrates have a long history of use in environmental monitoring. However, macroinvertebrate-based multimetric approach has not been well developed to assessment aquatic ecosystems in China, particularly in lake ecosystems. Eutrophication has been recognized as one of the main pressures affecting shallow lakes in China and elsewhere and it is thus desirable to quantify its effects on ecological integrity of lake ecosystems. Here, 41 subtropical shallow lakes in the Eastern Plain Lake Ecoregion of China were sampled and defined as three groups along eutrophication gradients. A macroinvertebrate-based multimetric index, consisting of three taxonomic metrics (No. of Gastropoda taxa, biological pollution index, and Margalef index) and two functional metrics (functional evenness and relative abundance of deposit feeder) was developed based on the datasets of the 41 lakes, and the results of multiple linear regression showed that the MMI was significantly related to the concentration of TP and macrophyte cover. This finding indicated that the MMI could characterize the influence of eutrophication on lake ecosystems. Our results also indicated that functional metrics could complement the information provided by taxonomic metrics, and we recommend to properly use functional metrics in lake biomonitoring. The macroinvertebrate-based MMI proposed here is the first attempt using biological quality element to assess the ecological status of shallow lakes in the view of eutrophication at the regional scale and could provide complementary information to traditional water quality assessment for the development of management strategies.

Seasonal variation and ecological importance of tannin and nutrient concentrations in Casuarina equisetifolia branchlets and fine roots

In this study, we investigated the effects of environmental factors on plant phenolic variability, seasonal dynamics of total phenolic content (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT), protein precipitation capacity (PPC) and nutrient content in the branchlets and fine roots of Casuarina equisetifolia. TP and TCT concentrations in branchlets were lowest in the spring, then increased in summer and autumn, similar to the seasonal dynamics in air temperature. TP and TCT concentrations in fine roots were highest in summer, coinciding with heavy precipitation. In general, TP and TCT concentrations were higher in branchlets than in fine roots. No significant difference was found in C concentration among various seasons for either branchlets or fine roots. Branchlets had significantly higher N and P concentrations than fine roots in most seasons. The C/N and N/P ratios in branchlets were significantly lower than in fine roots in all seasons, except summer. The relationship between branchlets and fine roots was significant for C, P and FBCT, but no significant relationships were found for N, TP, ECT, PBCT and TCT. Additionally, TP and TCT content were each significantly correlated with PPC in branchlets and in fine roots. Both TP/N and TCT/N ratios were highest in the autumn for the branchlets and in the summer for fine roots. The results indicate that high temperatures lead to increased tannin production in branchlets, but that the tannin content in fine roots is mainly affected by precipitation. Tannin content was greater in branchlets than in fine roots, which may indicate that selective pressure is greater on branchlets than on fine roots.

Low temperature nutrient removal from municipal wastewater by purple phototrophic bacteria (PPB)

This study evaluated the performance of purple phototrophic bacteria (PPB) at temperatures of 22 °C and 11 °C in a membrane photobioreactor. PPB performance and Monod parameters were evaluated at 11 °C and were compared to PPB performance at 22 °C. At 22 °C, the optimum HRT with respect to meeting target limits of TCOD < 50 mg/L, TN < 10 mg/L, and TP < 1 mg/L was 9 h with ethanol supplementation at 300 mgCODL−1 noting that ethanol was only needed to meet the TN limit. However, at 11 °C, the photobioreactor achieved effluent TCOD, TN, and TP concentrations of 70 mg/L, 10 mg/L, and 1.2 mg/L respectively at 9 h HRT and 300 mgCOD/L ethanol addition. Monod kinetic parameters Ks, K, Y, and Kd were determined to be 20 mgCOD/L, 1.8 mgCOD/(mgVSS.d), 0.54 mgVSS/mgCOD, and 0.09 d−1 at 22 °C and 31 mgCOD/L, 1.2 mgCOD/(mgVSS.d), 0.51 mgVSS/mgCOD, and 0.07 d−1 at 11 °C respectively.

A rule of hydrological regulating on nutritional status of Poyang Lake, since the operation of the Three Gorges Dam

Abstract Anthropogenic activities have aggravated nutritional status of lakes. Hydrological regime of Poyang Lake has been altered since the operation of the Three Gorges Dam (TGD). Will this further affect the nutritional status of Poyang Lake? We studied the dynamic changes of the nutritional status of Poyang Lake between 2003 and 2015 under this new hydrological regime. A regulating rule of hydrological regime on lake nutritional status was found, in which change in water storage and accompanying nutrient input acted as the dominant influencing factors. The rule was represented as a fitting function of the ratio of change in storage (ΔQ, ΔQ = Qoutflow − Qinflow) to nutrient input (TN − TP)input) and the nitrogen and phosphorus concentration in the lake water. The specific functional formulas were as follows: y1 = 148.32x2 − 362.51x + 229.83 (R2 = 0.8771, lower boundary) and y2 = −74.92x2 + 135.25x − 17.139 (R2 = 0.9049, upper boundary) for TN; y1′ = 94009x2 − 24302x + 1345 (R2 = 0.9729, lower boundary) and y2′ = −68439x2 + 7588x + 514.42 (R2 = 0.8588, upper boundary) for TP. In the lake management, the hydrological regulating of the upper boundary and the lower boundary should be expressed as: the range of ΔQ/TNinput was 8.22–43.07 and 8.35–35.06 respectively, similarly, 316.64–723.98 and (−218.37)−523.33 of ΔQ/TPinput range. This rule applied to the following scenarios: concentrations of TN and TP were below 1.60 mg L−1 and 0.133 mg L−1, and continue to increase over a 4–5 years. This study provided a key practical reference for the management of dam-impact lakes worldwide.

Essential cryoglobulinemia: A case report

Excess phosphorus (P) loading due to anthropogenic activities has been identified as a primary cause of surface water eutrophication, but it is controversial whether P is a contributor to groundwater contamination. In this study, subsurface transport of P to groundwater and its environmental risk across different land uses was investigated in a karstic springs basin, Florida, USA. Eleven sites including 5 agricultural sites, 5 urban, and 1 pine plantation were selected. Boreholes were drilled to collect soils from surface, vadose zone, and aquifer at 0.6 m depth intervals. Water-extractable P (WSP), Mehlich 3-P, Al, and Fe, soil P storage capacity (SPSC), and P sorption isotherm parameters were obtained for soils from selected depths. We found that agricultural sites particularly horse farms, and urban sites with golf courses and septic tanks showed high risk of P leaching with TP concentrations in the groundwater above the numeric criteria for streams in the north central Florida (0.3 mg L−1). Besides land use which reflected P loadings in the surface soils, significant positive correlations of P sorption maximum (Smax) with M3-Fe, Al, and organic matter, and the precipitation of P by calcium bicarbonate, imply the mechanism regulating soil P attenuation in vadose and saturated zones, respectively. Negative SPSC values were significantly negatively correlated with WSP in all the zones, suggesting the applicability of SPSC in deep soils. Moreover, high TP concentration was observed in the groundwater at one site where the SPSC value changed from positive in the surface soils to negative in the subsoils, indicating that an additive SPSC value to water table would be more robust for evaluating the potential of P leaching before moving down to the limestone area.

No Ontogenetic Shifts in C-, N- and P-Allocation for Two Distinct Tree Species along Elevational Gradients in the Swiss Alps

Most of our knowledge about forest responses to global environmental changes is based on experiments with seedlings/saplings grown in artificially controlled conditions. We do not know whether this knowledge will allow us to upscale to larger and mature trees growing in situ. In the present study, we used elevation as a proxy of various environmental factors, to examine whether there are ontogenetic differences in carbon and nutrient allocation of two major treeline species (Pinus cembra L. and Larix decidua Mill.) along elevational gradients (i.e., environmental gradient) in the Swiss alpine treeline ecotone (~300 m interval). Young and adult trees grown at the same elevation had similar levels of non-structural carbohydrates (NSCs), total nitrogen (TN), and phosphorus (TP), except for August leaf sugars and August leaf TP in P. cembra at the treeline. We did not detect any interaction between tree age and elevation on tissue concentration of NSCs, TN, and TP across leaf, shoot, and root tissues for both species, indicating that saplings and mature trees did not differ in their carbon and nutrient responses to elevation (i.e., no ontogenetic differences). With respect to carbon and nutrient allocation strategies, our results show that young and adult trees of both deciduous and evergreen tree species respond similarly to environmental changes, suggesting that knowledge gained from controlled experiments with saplings can be upscaled to adult trees, at least if the light is not limited. This finding advances our understanding of plants’ adaptation strategies and has considerable implications for future model-developments.

Impact of Actual Domestic Sewage and Simulated Wastewater on an Aerobic Granular Sludge System

Sludge returned from the secondary sedimentation tank of a sewage treatment plant is inoculated into two sequencing batch reactors (SBR):R1 and R2. Simulated wastewater and actual domestic sewage are used as the influents of R1 and R2, respectively, in order to study the impact of the influent water quality on the formation at normal temperature (20-30℃) and the stable operation of the system when the temperature changes. The results show that both R1 and R2 start successfully with 25 d and 42 d, respectively. The average size of the aerobic granular sludge in R1 and R2 is 1200 μm and 750 μm when the sludge granules stabilize. The average concentrations of COD, TP, and TN in the R1 and R2 effluent are 22.53, 0.48, and 7.70 mg·L-1 and 49.73, 0.49, and 14.55 mg·L-1, respectively, with average removal rates of 90.60%, 90.34%, and 87.85% and 79.74%, 88.59%, and 79.25%. When the temperature drops to 5-16℃, the granular sludge in R1 disintegrates, the removal rates of COD and TP are basically unchanged, the average concentration of TN in the effluent increases to 29.03 mg·L-1, the average removal rate decreases to 48.81%, and the denitrification performance is suppressed. The granular sludge in R2 remains stable; the average concentrations of COD, TP, and TN in the effluent are 14.31, 0.50, and 12.24 mg·L-1, and the average removal rates are 92.42%, 93.37%, and 86.28% respectively. The effluent reaches the IA standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant". Both the simulated wastewater and actual domestic sewage can cultivate aerobic granular sludge successfully, but the aerobic granular sludge in the domestic sewage is more compact in structure, effectively suppresses the expansion of filamentous bacteria when the temperature drops to 5-16℃, and is more resistant to changes.

Spatial Distribution Characteristics of Nutrients and Chlorophyll A in the Lancang River Basin Under Cascade Reservoirs

Construction of cascade reservoirs in Lancang River had a certain influence on the ecological water environment of the basin, dividing the water into natural reaches and reservoir reaches. To explore the impact of the cascade reservoirs on the ecological environment, the nutrient and the chlorophyll a distribution data were measured in the natural reaches, reservoir reaches, and tributaries in June 2017. The results showed that the TN ranged from 0.37 to 1.22 mg·L-1, with an average of 0.70 mg·L-1, and the TP ranged from 0.01 to 0.19 mg·L-1, with an average of 0.04 mg·L-1. One-way ANOVA analysis showed significant spatial differences in the TN, with the TN concentration following the order tributaries > reservior reaches > natural reaches. However, the TP concentration did not show a significant trend. The chlorophyll a concentration varied from 2.6 to 10.2 μg·L-1, with a mean of 5.8 μg·L-1. Pearson correlation analysis showed significant relationships between the chlorophyll a concentration and the TP, water temperature, and Zeu/Zmix. The relationship between chlorophyll a and Zeu/Zmix was particularly significant, which indicated the Zeu/Zmix caused by thermal stratification may be the key factor influencing the growth of phytoplankton.

Relationships between diatom metrics based on species nutrient traits and agricultural land use.

We assessed how diatom metrics were related to different ranges of agricultural land use. Diatom assemblage composition, nutrients, and landscape characteristics were determined at 232 sites in eight agriculturally dominated study areas of the continental United States. Two regional groups based on differences in diatom relations to human disturbance were determined. Changes in diatom species composition were related to nutrients, pH, and conductivity in the eastern study areas (due to more wetlands) and more exclusively to nutrients in the west-central study areas. Homogenization of diatom flora among streams was related to high agricultural disturbance at this transcontinental scale. Species traits were developed separately for the east and west-central study groups and calculated two ways: indicator species analysis for taxa in low and high TN or TP conditions and weighted average partial least squares models of TN and TP concentration. These diatom metrics were significantly related to many indicators of agricultural land use in watersheds, especially percent row crops. Further analysis was conducted on only the west-central region due to its larger sample size. Overall, diatom metrics using species responses to N gradients were better related to agricultural land use than were species responses to P gradients. Most nutrient-based diatom metrics changed greatly in response to low ranges of percent row crops, but only a few high N diatom metrics responded to high row crop conditions. The greater response of diatoms to changes in low agriculture conditions may be due to past diatom evolution occurring when most waters had low nutrient conditions.

Effect of Influent Ammonia Concentration on a Biological Phosphorus Removal Granules System

Mature biological phosphorus removal granules were inoculated into a SBR. The effect of the ammonia concentration on biological phosphorus removal granules system was investigated by increasing the concentration of ammonia in the influent. The ability of the system to withstand ammonia loading was determined. The results showed that when the influent ammonia concentration was below 45 mg·L-1, the biological phosphorus removal granule system showed good performance. The TP removal efficiency was above 96%, the COD removal efficiency was over 89%. The effluent TP concentration and COD concentration were 0.4 mg·L-1 and 25 mg·L-1 respectively. The particle size was above 950 μm and the SVI was below 45 mL·g-1. When the influent ammonia concentration was 60 mg·L-1, the removal efficiency of TP was more than 95%. The effluent TP concentration was below 0.5 mg·L-1, the particle size was 760 μm, and the SVI was 56 mL·g-1. Furthermore, the biological phosphorus removal granules partially disintegrated and the metabolism and growth of PAOs began to be inhibited in the system. When the influent ammonia concentration reached 70 mg·L-1, the removal efficiency of TP was 70%, the effluent TP concentration was about 3 mg·L-1, the particle size was 570 μm, the SVI was 75 mL·g-1, and the value of PN/PS was about 7.50. The biological phosphorus granules severely disintegrated and the metabolism and growth of PAOs was severely inhibited in the system. Moreover, as the influent ammonia concentration increased, the protein increased and polysaccharide decreased from the microbial secretion of biological phosphorus removal granules. Moreover, the value of PN/PS increased, the biological phosphorus removal granules disintegrated, the particle size decreased, the SVI increased, and the structure and function of the biological phosphorus removal granules were destroyed.

Land cover impacts on storm flow suspended solid and nutrient concentrations in southwest Ohio streams.

Impacts between urban and agricultural land cover on storm flow water quality are poorly understood for the Eastern Corn Belt Ecoregion in SW Ohio. Storm flow water samples were collected from May 2017 to October 2017 across seven SW Ohio watersheds which ranged in urban land cover from 6% to 92% and in agricultural land cover from 4% to 70%. Two watersheds contained water resource recovery facilities (WRRFs). Percent agricultural land cover in a watershed and storm magnitude were primary explanatory variables for total suspended solid and total phosphorus concentrations. Total nitrogen, nitrate, and phosphate concentrations were primarily explained by the presence of WRRFs and percent agricultural land cover. Increased dissolved nutrient concentrations in watersheds with WRRFs indicate that WRRFs in the study area are ineffectively removing nitrate and phosphate from effluent. Results suggest that to improve water quality during storm flows, additional management efforts need to be focused on agricultural watersheds and WRRFs. PRACTITIONER POINTS: Storm flow water quality in the study area is significantly affected by land cover, WRRF Q, and storm Q. TSS and TP concentrations are best explained by percent of agricultural land cover in a watershed and magnitude of storms. TN, NO3 -N, and concentrations are best explained by WRRF Q, followed by the percent agricultural land cover. This study shows that agricultural land cover and WRRFs play a significant role in water quality degradation in SW Ohio.

Insights into the relationship between colony formation and extracellular polymeric substances (EPS) composition of the cyanobacterium Microcystis spp

Extracellular polymeric substances (EPS) were considered as fundamental substances in colony formation; however, the understanding of EPS composition remains limited. This study analyzed the content and composition of EPS fractions (soluble EPS, loosely bound EPS, and tightly bound EPS) of four Microcystis species from laboratory cultures in both unicellular and colonial morphologies, as well as colonies collected during Microcystis blooms, using fluorescence excitation - emission matrix spectroscopy combined with parallel factor analysis (EEM-PARAFAC). This method enables to make insight into protein-like and humic acid-like components but cannot detect polysaccharides. The EPS was successfully categorized into three humic acid-like components (C1 – C3) and a protein-like component (C4). Component C1 was discovered to be involved in colony formation and colony size growth of Microcystis. EPS content varied among Microcystis morphospecies, such as M. aeruginosa, M. wesenbergii and M. ichthyoblabe, and this was significantly affected by the environmental constraints rather than the morphospecies. The proportion of C1 relating to larger colony size was negatively correlated to temperature and concentrations of TN and TP. The tightly bound EPS directly promoted colony formation, but the soluble EPS or loosely bound EPS alone did not induce colony formation in Microcystis. These results advanced the current knowledge on the chemical materials involved in the colony formation of Microcystis and provided new clues in unicellular-multicellular transformation as well as colonial morphology changes in Microcystis.

Retinal and choroidal thickness in paediatric patients with hypoalbuminaemia caused by nephrotic syndrome

BackgroundA study was conducted to evaluate the choroidal thickness (CT) and retinal thickness (RT) in paediatric patients with hypoalbuminaemia caused by nephrotic syndrome (NS). We also studied the correlation between the subfoveal choroidal thickness (SFCT) and serum protein concentration.MethodsThis was a cross-sectional study. Fifty-one paediatric patients with hypoalbuminaemia caused by NS and 41 normal subjects were included in the study. Enhanced depth imaging optical coherence tomography (EDI-OCT) was performed to measure the RT and CT. The RT and CT were measured manually at intervals of 0.5 mm along a horizontal line through the macular fovea between 2.5 mm nasal and 2.5 mm temporal to the fovea. Clinical data including measurements of serum proteins were obtained.ResultsThe mean RTs at the T2.5, T2, N1.5, N2, and N2.5 locations and the average macular horizontal RT were slightly greater in the NS group than those in the control group. The mean CTs at all locations were significantly greater in the NS group than those in the control group; the difference was most significant at the fovea (373.8 ± 74.9 μm vs. 280.2 ± 57.1; p < 0.001). The SFCT in patients with NS was correlated with age (r = − 0.307, p = 0.003), body height (r = − 0.320, p = 0.022), body weight (r = − 0.343, p = 0.014), axial length (AL, r = − 0.237, p = 0.023), total protein (TP, r = − 0.302, p = 0.031), albumin (ALB, r = − 0.285, p = 0.042), prealbumin (PA, r = − 0.303, p = 0.033) and 24-h urine volume (UV, r = − 0.298, p = 0.034). Multiple linear regression analysis showed that the TP concentration and body weight had the highest correlation with the SFCT (R2 = 0.220, p < 0.05).ConclusionsThe macular RT is slightly increased and the macular CT is significantly increased in paediatric patients with hypoalbuminaemia caused by NS, indicating fluid accumulation in the retina and choroid. There is a negative correlation between the SFCT and serum TP concentration. Thus, the serum TP concentration is an important indicator of CT in patients with hypoalbuminaemia.

Fe(II)-dosed ceramic membrane bioreactor for wastewater treatment: Nutrient removal, microbial community and membrane fouling analysis

Ferrous dosing is used to reduce phosphorus concentration and alleviate polymeric membrane fouling in membrane bioreactor (MBR). However, limited studies have been conducted to investigate the impacts of ferrous dosing on ceramic membrane fouling, nutrient removal efficiency and microbial community. Accordingly, the aim of this study was to investigate the effect of intermittent ferrous dosing with Fe/P molar ratios of 2 and 1 (with a dosing frequency of every two days) on the overall nutrient removal, functional microbial changes and membrane fouling in ceramic membrane bioreactors (CMBR) in treatment of wastewater. TP concentration of 10 mg/L in influent decreased to 1.94 ± 0.62 mg/L (control), 0.38 ± 0.22 mg/L (Fe/P = 1) and 0.31 ± 0.18 mg/L (Fe/P = 2) in the effluent, respectively. Meanwhile, the effluent total nitrogen (TN) concentrations with Fe/P = 1 treatment (6.80 ± 2.02 mg/L) and Fe/P = 2 treatment (5.12 ± 2.28 mg/L) were lower than that of the control (7.72 ± 2.36 mg/L). Compared to Fe/P = 1, the TN removal performance was better for Fe/P = 2 mainly due to the increased abundance of denitrifying bacteria (Zoogloea and Acinetobacter). In addition, excess iron dose might have toxic effects on bacterial physiology, however the Fe concentrations that cause cell damage vary for different bacteria. The relative abundance of Zoogloea (aerobic denitrifying bacteria) continuously increased with ferrous addition (Fe/P = 2), while other bacteria including Dechloromonas, Hyphomicrobium and Thauera (anoxic denitrifying bacteria), Nitrospira (nitrifying bacteria) and Candidatus Accumulibacter (phosphorus accumulating organism) decreased sharply. Furthermore, membrane fouling was effectively moderated by ferrous dosing and Fe/P = 1 treatment showed improved membrane fouling mitigation than Fe/P = 2. Overall, intermittent ferrous addition in CMBR with Fe/P molar ratio of 1 was beneficial to the removal of nutrients (TP, TN and organics), enhanced succession of microbial community and membrane fouling mitigation.

Simulation analysis of the influence of heavy rainfall on urban lake

Urban lakes play a role in flood control and storage, they are also important urban landscape, which have certain requirements for water quality. In addition to the impact on the lake water quantity, the short-term heavy rainfall runoff carries a large pollution and has a great impact on the water quality, especially for urban lakes with relatively small reserves. However, there are few studies on the effects of heavy rainfall on lake hydrodynamics and water quality. In this paper, taking the rainfall of typhoon Fitow as an example, EFDC was used to simulate the hydrodynamic water quality process of West Lake in Hangzhou China during the Fitow period, the water level and water quality monitoring values were used to validate the model during this period. The simulation shows that the heavy rainfall had a great influence on the water level of the West Lake. Water level of West Lake crossed warning mark about 71 hours, with Sudi and Baidi Causeways were flooded about 57 hours. According to the simulation, as the TP concentration of early runoff was high, the TP concentration at the inlets of each sub-basin increased above 0.1 mg/L. After the early runoff, the TP concentration at the inlets began to decrease. The high concentration area gradually migrated to the downstream, and decreased gradually until it was discharged from the Shengtangzha Outlet, and water quality gradually returned to normal. Since the water level of West Lake increased significantly during the period, the influence of different drainage discharges was analyzed. The analysis shows that the highest water level of West Lake during Fitow period would fall below warning mark in case of increasing the flood discharge capacity to 46.8m3/s, which was 29m3/s more than current discharge. Otherwise there’s little effect on the spatial distribution of TP with the increasing of flood discharge. In conclusion, the main threat of short-term heavy rainfall to urban lake is flood control and drainage, meanwhile the impact of the heavy rain on water quality cannot be ignored. A perfect drainage and diversion system would make the water quality back to normal quickly after the heavy rainfall.

Thiophene Derivatives as Anticancer Agents and Their Delivery to Tumor Cells Using Albumin Nanoparticles.

A series of thiophene derivatives (TPs) were synthesized and evaluated for cytotoxicity in HepG2 and SMMC-7721 cell lines by MTT assay. TP 5 was identified as a potential anticancer agent based on its ability to inhibit tumor cell growth. Drawbacks of TPs, including poor solubility and high toxicity, were overcome through delivery using self-assembling HSA nanoparticles (NPs). The optimum conditions for TP 5-NPs synthesis obtained by adjusting the temperature and concentration of TP 5. The NPs had an encapsulation efficiency of 99.59% and drug-loading capacity of 3.70%. TP 5 was slowly released from TP 5-NPs in vitro over 120 h. HepG2 and SMMC-7721 cell lines were employed to study cytotoxicity of TP 5-NPs, which exhibited high potency. ROS levels were elevated and mitochondrial membrane potentials reversed when the two cell lines were treated with TP 5-NPs for 12 h. Cellular uptake of fluorescence-labeled TP 5-NPs in vitro was analyzed by flow cytometry and laser confocal scanning microscopy. Fluorescence intensity increased over time, suggesting that TP 5-NPs were efficiently taken up by tumor cells. In conclusion, TP 5-NPs showed great promise as an anticancer therapeutic agent.

Evaluation of nitrogen removal processes and microbial communities in eight full-scale municipal wastewater treatment plants

Wastewater treatment plants (WWTPs) face great challenges in developing countries, such as China, due to increasingly strict integrated wastewater discharge standard, especially for ammonium. Thus, it is very important to understand the limiting factor for ammonium removal in WWTPs. In this study, samples from 8 full-scale municipal WWTPs with different treatment processes in Pearl River Delta (PRD) area were evaluated. Bacterial and archaeal communities were investigated by high-throughput sequencing, activity of aerobic ammonium and nitrite oxidation, denitrification and anammox processes were evaluated. Nitrite, nitrate and TP concentration were strongly correlated with bacterial and archaeal composition in WWTPs based on canonical correspondence analysis (CCA). Aerobic ammonium oxidation activities were over 10 times lower than aerobic nitrite oxidation, denitrification and anammox activities in WWTPs samples, which indicated nitrogen removal activities in WWTPs were limited by aerobic ammonium oxidation, because of lack of nitrite/nitrate for denitrification and anammox. Moreover, a technology-dependent shaping of microbial diversity and nitrogen removal activity was observed. The highest bacterial diversity and nitrogen removal activities were achieved in sequencing batch reactor (SBR) and Modified Anaerobic-Anoxic-Oxic (MAAO) processes, which implied the advantage of these two treatment technologies in nitrogen removal. Therefore, this study suggested enhancing activity of aerobic ammonium oxidation might be a potential solution, for promoting ammonium removal and benefiting sustainable management of WWTPs in future.

Statistical analysis of the water pollution indicators pertaining to treated municipal sewage introduced to the river

The assessment of the ratio of self-purification processes in the natural environment, including the water bodies of streams and rivers is possible by the means of the numerical modelling. Nonetheless, the reliability of results of the qualitative numerical calculations may be affected by the quality of the collected input data and efficiency of the model calibration. The commonly required input data include pollutants characteristics and coefficients for empirical equations of their transport and decay, while calibration of a model requires series of measurements of selected pollutants concentration in water. This paper presents studies of concentration of pollutants measured in the treated sanitary wastewater discharged to the Bystrzyca river from municipal wastewater treatment plant, and their concentrations measured directly in the river, above and below the location of discharge point. The performed qualitative measurements of treated sewage discharged from municipal wastewater treatment plant and water of the Bystrzyca river included determination of COD, BOD5, N-NH4, N-NO2, N-NNO3, TKN, TN, TP and TSS concentration. The presented results of measurements are the first step in development and calibration of the model, allowing to successfully predict the influence of discharged sanitary wastewater on quality of water in the river.

Distribution Characteristics of Organic Matters and Nutrients in Surface Sediments of Yeongsan River Basin

This study was carried out to assess the distribution and pollution level of organic matters and nutrients in surface sediments of the Yeongsan River Basin. The surface sediments were collected from the mainstream (12) and tributaries sites (4) for two years from 2015 to 2016, and the particle sizes, organic matters (Ignition Loss, COD, TOC) and nutrients (TN, TP, SRP) were analyzed. The distribution of particle sizes was dominated by sand in the upstream sites (MS1-MS7) and by silt loam in the downstream sites (MS8-MS12), but MS3 and MS6, located slightly upstream of the two weirs, were found to be mostly loamy sand and silt loam, respectively. As a results of the correlation assessment, the organic matters (IL, COD, TOC) were strongly correlated with particle sizes, while the nutrients (TP, SRP) were weak except for TN. The concentrations of organic matter and nutrient were higher at the downstream and the sites nearby the two weirs (MS3, MS6). In particular, the TP concentration at the MS3 site sampled in the second half period of the years was higher than that in the first half periods. Comparing of sediments criteria, the organic matters and nutrients were evaluated to have almost no toxic effects at all sites.

An integrated gravity-driven ecological bed for wastewater treatment in subtropical regions: Process design, performance analysis, and greenhouse gas emissions assessment

This study focused on the development of an integrated gravity-driven ecological bed (IGEB) for treating wastewater from agritainment activities in subtropical region. An integrated treatment process including multiple modules was designed. A filed scale treatment system was built and operated at an agritainment farm in Xiamen, China. Although the developed system had no requirement for electric power, it presented the good performances in pollutant removal and shock resistance. The effluent concentrations of COD, NH3-N, and TP reached 50.4, 10.4, and 0.9 mg/L, with removal rates of 78.0%, 72.7%, and 69.6%, respectively. The IGEB modules of anaerobic tank, multiple soil layer system and subsurface flow constructed wetland functioned as preliminary, secondary, and polishing treatments, respectively. The total greenhouse gas (GHG) emissions of IGEB system were about 21.3 kg CO2-eq/d. IGEB system had a significant advantage in terms of mitigation of GHG emissions over centralized wastewater treatment. In addition, the total cost of IGEB system was about 0.3 RMB Yuan to treat 1 tonne wastewater. As a sound decentralized wastewater treatment technique, it provides a sustainable solution for the environmental pollution issues related to agritainment activities.