Purification Effect of Fish–Algae Coupling on Nitrogen and Phosphorus in Shrimp Aquaculture Effluent

In this study, low-temperature alkali-modified fly ash and polymeric aluminum chloride(PAC) for the removal of total phosphorus, COD and ammonia nitrogen, from wastewater was systematacially investigated. The removal rate of ammonia nitrogen was 81.10%, and the removal rates of phosphorus and COD were 90.21% and 55.48%, respectively., when a dosage of the alkali-modified fly ash was 5g/L, the amount of PAC was 50mg/L, and the mixing time was 39min. In comparison with raw fly ash, the removal rate of ammonia nitrogen is 80.16% higher than that of the original fly ash, and the removal rate of total phosphorus is 35.48% higher. Fly ash with improved surface can be used as an alternative adsorbent to flocculate and precipitate in cooperation with polymeric aluminum chloride, which can be applied to the treatment of total phosphorus, COD and ammonia nitrogen in the sewage. This study provides a theoretical basis for the coagulation adsorption method and realizes the utilization of fly ash.

The total suspended particle (TSP) concentration, dry deposition and wind speed were measured with a PS-1 sampler, a dry deposition plate and a Weather Monitor II (#7440), respectively, at the Experimental Farm of Thunghai University in Taiwan. Taiching Industrial Park, Taichung Cong Road (traffic) and a hospital incinerator are close to the sampling site. The sampling time was from August 2001 to December 2001. The average dry deposition flux, the TSP concentration, dry deposition velocities, average wind speed and maximum wind speed were recorded as 617.7 ± 281.4 mg/day/m², 117.5 ± 17.6 µg/m³, 5.9 ± 2.2 cm/s, 2.7 ± 1.3 m/s and 7.6 ± 2.3 m/s, respectively, at this sampling site. Good correlation coefficients (R) of the TSP concentration and the dry deposition flux with wind speed were found, with values of 0.46 and 0.50, respectively. The concentrations and dry deposition of the total metallic elements were also obtained. The results indicated that the concentrations of anthropogenic elements (Pb, Mn, Cd, Ni, Cr and Zn) were mostly higher than those obtained in other studies around the world. The average dry deposition fluxes and TSP concentrations for Zn and Pb were 0.45 and 0.42, respectively. The same phenomenon was also observed for Fe and Mg (R = 0.59 and 0.65). The results indicate that these elements were all coming from the same emission sources at the farm sampling site.

Urban rainfall runoff pollution has become a major reason for water eutrophication problem in the process of urbanization in China, while phosphorus is a significant restrictive factor that influences primary productivity of freshwater system. It's rather significant to conduct phosphorus control in waste water with engineering measures. This research, based on material balance research of phosphorus in artificial wetlands, HRT (hydraulic retention time) and analysis of wetland plant photosynthesis and removal rate of phosphorus, simulates purification of phosphorus in urban runoff sewage by artificial wetland system. Experiment shows that removal rate of total phosphorus in urban runoff sewage by artificial wetland system reaches 42.23%-60.89%, and contribution rate in removal of phosphorus which is assimilated and absorbed by plants is 14.74%; contribution rate in removal of phosphorus which is accumulated and absorbed by substrates is 43.22%; contribution rate in removal of phosphorus which is absorbed by means like microorganisms is 2.93%. Pollutant absorption by substrates is a process of dynamic equilibrium. With extension of HRT, phosphorus removing effect of wetlands present an increasing and then decreasing tendency; Net photosynthetic rate and TP removal rate of canna and reed have significant positive correlation, and correlation coefficients are respectively 0.941(P<0.001) and 0.915(P<0.05). Substrates and plants are main pathways for phosphorus removal of artificial wetlands, covering 95% of the total removing effect.

Performance of an innovative step-feed An-M(A/O)-MBR process for nutrients removal

In order to achieve simultaneous nitrogen and phosphorus removal in low-C/N urban sewage, a sequencing batch reactor (SBR) was operated in anaerobic/aerobic (A/O) mode. Keeping the total aeration volume at 900 L, the aeration strategy was adjusted. The uniform aeration of 2.81 L·(h·L)-1 was changed to "high/low aeration" with high strength 4.22 L·(h·L)-1before low strength 1.88 L·(h·L)-1, and "low/high aeration" with low strength 1.88 L·(h·L)-1 before high strength 4.22 L·(h·L)-1. The experiment investigated the nitrogen and phosphorus removal performance and sludge characteristics of the system under different aeration strategies. The results showed that the nitrogen and phosphorus removal performances of the system under high/low aeration were the best. The effluent concentrations of NH4+-N, NO2--N, NO3--N, and TP were 0, 0.15, 8.12, and 0.04 mg·L-1, respectively. The removal rates of total nitrogen (TN) and total phosphorus (TP) were as high as 78.33% and 99.19%, respectively. Simultaneous nitrification endogenous denitrification (SNED) was clear, with the SNED ratio at 77.08%. Compared with uniform aeration, the system nitrification rate and denitrification rate increased, and the denitrification rate reached 14.33 mg·(g·h)-1, which was the maximum value during the whole operation; the solidity, sedimentation performance, and stability of granular sludge were improved, and the sludge volume index (SVI) was 23.49 mL·g-1. After adjusting the aeration strategy to low/high aeration, the nitrogen and phosphorus removal performance of the system deteriorated, and the removal rates of TN and TP were reduced to 51.26% and 58.32%, respectively. However, the system had the best nitrification performance with ammonia oxidation rate and nitrate production rate at 14.92 mg·(g·h)-1and 7.50 mg·(g·h)-1, respectively, which were their maximum values during the whole operation. Simultaneously, the filamentous bacteria in the granular sludge multiplied, the granular structure became loose, the sedimentation and stability all worsened, and the SVI rose to 40.76 mL·g-1.

Introduction: In recent years, dust storms frequently have occurred in large areas of the western half of Iran. Dust particles have negative effects on the environment and living animals, especially men's lives; hence, the current study was conducted with the aim of evaluation of airborne microorganisms and the concentrations of particulate and respirable matter causing from dust storm. Materials & methods: This cross - sectional study was done in Ilam city (2012). For sampling and reading of TSP amounts used from direct reading devices in concentration range of 1µg/m3-2500 mg/m3. Cyclone was used for determination of respirable dusts with diameter less than ten microns. Also to determine microbial state of dusts used from the cellulose membrane filters (37 mm diameter). Finally, data were analyzed with spss software. Findings: Results showed that the highest concentration of total suspended particles (TSP) and respirable particles (PM10) have been recorded in June with the amount of 22.5 and 1.3 mg per cubic meter. Comparison of Ilam air quality with standard values ​​( less-than 150 μ g/m3) for respirable particles and total suspended particles showed that except in August that TSP concentration was below the standard value. In other months, the concentration of PM10 and total suspended particles were above the standard amount. Discussion & conclusions: The results of this study showed that particulate concentration levels were higher than those of standard values and also contained microorganisms which can threaten human health; therefore, it seems necessary to control them.

Based on the discharge characteristics of agricultural non-point source pollution in the headstream region of the Kaihui River-a typical small agricultural watershed, an integrated ecological engineering treatment system (IEETS) was constructed with ecological wetland as the core unit to control the pollution. The nitrogen (N) and phosphorus (P) removal performances of the IEETS were discussed in this study. The results showed that the dominant source of N and P in the study area was livestock and poultry breeding, which was urgent to control. The monitoring results indicated that the ecological wetland treatment project resulted in average total nitrogen (TN) and total phosphorus (TP) removal rates of 87.1% and 90.9%, respectively, when treating mixed decentralized domestic and swine wastewater treatment. The multi-stage constructed wetlands had an average of 85.7% of TN and 84.9% of TP removal for mixed farmland drainage and decentralized swine wastewater. The removal rates for landscape-based ecological wetland were within the range of 27.1%-67.4% for TN and 13.3%-81.5% for TP in the catchment terminal water. The total interception amount of TN and TP by the IEETS was 5292 kg·a-1 and 1054 kg·a-1, accounting for 35.3% and 43.6% of total pollution loads in the headstream region, respectively. These findings illustrated that the IEETS presents promising treatment results on non-point source pollution, and is suitable for widespread applications to wastewater treatment in small watersheds of southern China.

The new-type electrolysis-integrated ecological floating beds (EEFBs) were set up to study their water removal ability due to the excellent water treatment capacity of electrolysis, this enhanced EEFBs were made of polyethylene filled with biochar substrate and in middle of the substrate placed the Mg-Al alloy served as anode and graphite served as cathode. The results show that removal rates of total nitrogen (TN), ammonia nitrogen (NH3-N), total phosphorus (TP) and phosphate (PO43−-P) by the EEFBs increased 53.1%, 96.5%, 76.5% and 74.5%, respectively. The electrolysis reaction was the main pathway for TN and TP removals in the EEFBs. A higher concentration of hydrogen autotrophic denitrification bacteria was recorded in the substrate of the EEFBs than that in the traditional ecological floating beds (EFBs) (p < 0.05), suggesting that the electrolysis may have enhanced the NO3−-N removal efficiency of the EEFBs by promoting the growth and reproduce of hydrogen autotrophic denitrification bacteria. The in-situ formation of Mg2+ and Al3+ ions from a sacrificial Mg-Al alloy anode, caused PO43−-P and other suspended matter flocculation, improved phosphorus removal and simultaneously reduced turbidity. Thus, electrolysis-integrated ecological floating bed has high nitrogen and phosphorus removal potential in eutrophic water.

In this research, the domestic wastewater was treated by full-scale Biolak/A2O process. The effects of dissolved oxygen (DO) on nitrogen and phosphorus removal of the system in oxic zone were investigated. Controlling to DO at 0.8-1.5 mg/L, the treatment efficiency of system was near optimal with the total nitrogen efficiency of 69.45%. The simultaneous nitrification and denitrification could be achieved under this condition. Based on the calculation equations and transformation pathways of nutrients, about 23.71% total nitrogen (TN) was removed by multistage A/O system in the oxic tank. When DO was 1.0-3.0mg/L, the total phosphorus (TP) removal efficiency was the highest at 73.97%. DO in the range of 1.0-1.5mg/L was optimal for the nutrient removal in Biolak/A2O process, removal efficiency of TN and TP were 68.87% and 73.68%. TN and TP of the effluent were 12.02mg/L and 0.95mg/L, respectively.

A novel Si–Al porous clay material W (reprocessed from ceramic waste) was used for Acidovorax sp. strain PM3 immobilization to promote the growth of strains and improve nitrogen and phosphorus removal performance in water treatment systems. The porous clay material W was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy indicating that porous clay material W was a type of mullite with 63.52 m2/g specific surface area. After immobilization, the maximum biomass increased 2.7 times the specific growth rate and the removal rates of chemical oxygen demand (COD), ammonia (NH4+–N), and total phosphorus (TP) by the immobilized PM3 were 42.99, 29.19, and 11.76% higher than the free strain after 24 h. The Monod equation showed that the growth rate and processing speed of immobilized PM3 increased. The maximum adsorption capacities of COD and NH4+–N onto porous clay material W were 2.33 and 0.32 mg/g on the basis of Langmuir isotherm. The removal capacities of COD, NH4+–N, and TP by the immobilized PM3 were 588.24, 20.37, and 5.06 mg/l, respectively, as shown by kinetic studies. These results demonstrated that porous clay material W could improve the efficiency of microbial nitrogen and phosphorus removal, and the immobilized microorganism system could effectively treat domestic sewage. The adsorption isotherms can well describe the adsorption process. The maximum adsorption capacity of COD and NH4+–N on porous clay material W is 2.33 and 0.32 mg/g, respectively. Kinetic studies showed that the removal capacity of immobilized PM3 to COD, NH4+–N, and TP was 58.824, 20.37, and 5.06 mg/l, respectively.

Ambient TSP concentration and dustfall in major cities of China: Spatial distribution and temporal variability

Trace elements in atmospheric particulate matter over a coal burning power production area of western Macedonia, Greece

Air Pollution and Hospital Admissions for Respiratory Disease in Certain Areas of Korea: Belong Cho, et al. Department of Family Medicine, Clinical Research Institute, Seoul National University Hospital, Seoul National University—Recently studies reporting the incidence of diseases at air pollution levels below the recognized standard levels are increasing and the issue is becoming a matter of concern. We therefore examined the relationship between the level of air pollution in three areas of Korea and the incidence of respiratory diseases. Poisson regression models were used to account for day‐of‐the‐week effects and nonparametric smoothing to make adjustments for season and weather in this time series analysis. The levels of air pollution across the three selected areas were characterized by the total suspended particle (TSP) concentration, which in Daejon was 61.28 ± 29.22, in Ulsan 72.01 ±25.99, and in Suwon was 82.84 ± 30.18. The total number of hospitalized cases due to respiratory diseases during the study period was 5,446. The relative risk of hospitalization due to respiratory diseases caused by air pollutants after accounting for seasonal and temperature effects were as follows:‐CO (R.R.; 1.21, 95% C.I.; 1.02‐1.44) in a residential area (Daejon), and NO2 (R.R.; 1.47, 95% C.I.; 1.03‐2.10) and CO (R.R; 2.51,95% C.I.; 1.06‐5.93) in a heavily industrialized area (Ulsan), and were statistically significant. When the TSP concentration was manipulated as a quintile dummy variable, the relative risk of admission increased by 2.48% (95% C.I.: 1.82%—3.15%) for every quintile increase. In conclusion, respiratory disease admissions are related to NO2, CO, and TSP concentrations below the environmental standard, but the significance of this relationship was area dependent.

Superposition effect of floating and fixed beds in series for enhancing nitrogen and phosphorus removal in a multistage pond system

Energy is essential for the operation of wastewater treatment systems. Simultaneously, it can be a factor facilitating the electrochemical purification processes. Previous studies have shown that under specific conditions, there is no technological justification for using bio-electrochemical reactors designed for the simultaneous removal of both phosphorus and nitrogen compounds. This is because similar dephosphatation process effects can be achieved in an electrochemical reactor. Additionally, in a bio-electrochemical reactor, a portion of the organic substrate introduced for biological treatment is lost due to the electrocoagulation process. The aim of the research was to determine the influence of low direct current densities (0.4–2.0 A/m2) on the rate and efficiency of phosphorus and other compound removal in a sequencing electrochemical reactor treating real wastewater from a greenhouse with low organic compound content. In the conducted studies, an increase in electric current density resulted in an increase in the removal rates of phosphorus from 26.45 to 34.79 mg/L·h, nitrogen from 2.07 to 6.58 mg/L·h, and organic compounds from 0.44 to 1.50 mg/L·h. This corresponded to maximum removal efficiencies of 88.6 ± 2.5% for phosphorus, 7.4 ± 2.5% for nitrogen, and 51.1 ± 8.3% for organic compounds. As a result of electrocoagulation, sludge rich in phosphorus was obtained, ranging from 347 ± 38 mg/L (18.1% P) to 665 ± 36 mg/L (11.7% P). The obtained results can be utilized in the future for the development of two-stage systems for wastewater treatment with a low content of organic compounds, aiming at the removal of phosphorus and nitrogen.