Trends in total phosphorus and total nitrogen concentrations of tributaries to the Swan-Canning Estuary, 1987 to 1998

2001 ◽  
Vol 15 (13) ◽  
pp. 2411-2434 ◽  
Author(s):  
Robert Donohue ◽  
W. Angus Davidson ◽  
Norman E. Peters ◽  
Samuel Nelson ◽  
Brad Jakowyna
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Nitrogen Concentrations

Simultaneous Removal of Phosphorus and Nitrogen by Sequencing Batch Reactor Activated Sludge Process

1985 ◽  
Vol 17 (11-12) ◽  
pp. 315-316
Author(s):  
Mitsumasa Okada ◽  
Ryuichi Sudo
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Batch Reactor ◽  
Simultaneous Removal ◽  
Activated Sludge Process ◽  
Nitrogen Concentrations ◽  
Stage 1 ◽  
Activated Sludge Processes

Abstract–Phosphorus removal by biological means in continuous-flow aerobic/ anaerobic activated sludge processes is now in a stage of full-scale operations. The similar aerobic/anaerobic treatment is also found in biological processes for nitrogen removal by nitrification followed by denitrification. These processes are successfully applied not only to continuous-flow system but also to sequencing batch reactor (SBR) activated sludge processes, whereas little attempts have been reported on phosphorus removal in SBR activated sludge processes. It is most probable that both phosphorus and nitrogen in addition to organic matter can be removed by the SBR activated sludge processes if aerobic and anaerobic treatments were properly incorporated into a cycle of batch operation. Laboratory scale experiments on aerobic/anaerobic operations of the SBR processes were conducted aiming at simultaneous removal of phosphorus, nitrogen, and organic matter without any addition of chemicals. SBR of 5 1 in working volume was fed with synthetic wastewater in which TOC = 120-200 mg/l, BOD = 200-400 mg/l, total phosphorus = 6-12 mg/1 and total nitrogen = 36-60 mg/1. The following sequence of operations were conducted in a batch cycle; 1) mixing and inflow of wastewater, 2) aeration and mixing, 3) mixing, 4) aeration and mixing, 5) settling and 6) decanting. It was secured from continuous monitoring of dissolved oxygen concentration in the mixed liquor that both anaerobic (stages 1 and 3) and aerobic (stages 2 and 4) treatments were repeated twice in a cycle. In some operations, stages 3 and 4 were omitted for comparison, i.e. anaerobic and aerobic treatments were conducted only once per cycle. The volume of mixed liquor before the inflow of wastewater at the beginning of a cycle (low level) ranged from 33 % to 50 % of that during full volume stages from 2 to 5 (high level). In stage 6, the supernatant was discharged down to the low level and followed by the next cycle of operation. The length of time for a cycle of operation was β h or 9.5 h. Among various types of operations tried, the following sequence was the best in the quality of effluent; 1) 2 h for mixing and inflow, 2) 3 h for aeration and mixing, 3) 3 h for mixing, 4) 20 min for aeration and mixing, 5) 1 h for settling, and 6) 10 min for decanting in a cycle of 9.5 h if influent BOD, total phosphorus and total nitrogen concentrations were 400 mg/1, 12 mg/1 and 60 mg/1, respectively, and BOD loading was 0.68 kg/cu m/d. Total phosphorus and nitrogen concentrations in the effluent were 1.2 mg/1 and 8.0 mg/1, respectively. Similar results were obtained in operations where anaerobic and aerobic treatments were repeated twice in a cycle. In operations where effluent quality was satisfactory, release of phosphorus from the sludge was observed in stage 1. The reactor concentration of filterable total phosphorus (FTP) increased rapidly and its maximum value observed at the end of the stage was ca. 50 mg/1. Phosphorus uptake under aerobic condition (stage 2) decreased FTP to the level of effluent FTP. The luxury uptake of phosphorus by the sludge was noted, i.e. phosphorus content in the sludge ranged from 2.0 % to 4.0 %(w/w). The release of phosphorus from the sludge and subsequent luxury uptake were not significant during stages 3 to 4, hence, further removal of phosphorus was not remarkable. Nitrate nitrogen concentration increased during stage 2 by nitrification. Denitrification was noted both in stages 1 and 3. In stage 1, filterable total organic carbon (FTOC) increased by the inflow of wastewater. It should be, therefore, utilized for denitrification as hydrogen donor. FTOC decreased rapidly after the initiation of aeration in stage 2 and little FTOC remained after the latter half of stage 2. Intracellular organic substances of the sludge, therefore, were regarded to be utilized for denitrification without any addition of chemicals at stage 3. In the best operation, from 50% to 70% out of total nitrogen inflow was removed by denitrification. Effluent BOD was less than 10 mg/l. Although further investigations would be required to determine optimum scheduling in a cycle such as the combination of anaerobic and aerobic periods, the ratio between low and high levels in the reactor, the length of a cycle, and etc. for a given wastewater, the SBR activated sludge process would be a promising wastewater treatment process for simultaneous removal of phosphorus, nitrogen and organiC matter by a single reactor. In spite of complicated operational sequence, full scale automatic operations of SBR activated sludge process would be possible economically even in small-scale plants by using recently advanced microcomputer technology.

scholarly journals Comparing nutrient reference concentrations in Nordic countries with focus on lowland rivers

AMBIO ◽  
2020 ◽  
Vol 49 (11) ◽  
pp. 1771-1783 ◽  
Author(s):  
Eva Skarbøvik ◽  
Jukka Aroviita ◽  
Jens Fölster ◽  
Anne Lyche Solheim ◽  
Katarina Kyllmar ◽  
...  
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Land Use Changes ◽  
Reference Conditions ◽  
Water Bodies ◽  
Lowland Rivers ◽  
Nitrogen Concentrations ◽  
Further Development

Abstract Reference conditions of water bodies are defined as the natural or minimal anthropogenically disturbed state. We compared the methods for determining total phosphorus and total nitrogen concentrations in rivers in Finland, Norway and Sweden as well as the established reference conditions and evaluated the possibility for transfer and harmonisation of methods. We found that both methods and values differed, especially for lowland rivers with a high proportion of agriculture in the catchment. Since Denmark has not yet set reference conditions for rivers, two of the Nordic methods were tested for Danish conditions. We conclude that some of the established methods are promising but that further development is required. We moreover argue that harmonisation of reference conditions is needed to obtain common benchmarks for assessing the impacts of current and future land use changes on water quality.

scholarly journals Simulation of the Parameters Effecting the Water Quality Evolution of Xuanwu Lake, China

2021 ◽  
Vol 18 (11) ◽  
pp. 5757
Author(s):  
Min Pang ◽  
Weiwei Song ◽  
Yuan Liu ◽  
Yong Pang
Keyword(s):  
Water Quality ◽  
Diffusion Coefficient ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Water Environment ◽  
Water Diversion ◽  
Nitrogen Concentrations ◽  
Implementation Effect ◽  
Degradation Coefficient

After years of water environment improvement, China’s water quality has improved to some extent in recent years. However, different water areas have different characteristics of water pollution. The paper used mathematical models to investigate the influence of different parameters on the water quality of Xuanwu Lake, China. The predominant focus was on the nutrients concentration due to changing the amount of pollutants, degradation coefficient, water diversion discharge and diffusion coefficient. The results showed that the amount of pollutants had the most significant impact, followed by the degradation coefficient. The total phosphorus and total nitrogen concentrations of Xuanwu Lake increased with the increase of the amount of pollutants. The water quality of Xuanwu Lake decreased significantly with the increase of degradation coefficient. Increasing the water diversion discharge will not only make a big difference in water quality, but it will also worsen the water quality. The effect of the amount of pollutants on Xuanwu Lake total phosphorus and total nitrogen is 4.1 and 5.7 times that of water diversion discharge. The influence of total phosphorus and total nitrogen in the degradation coefficient scheme is 3.5 and 6.2 times that of the water diversion discharge scheme. The diffusion coefficient has almost no effect on the water quality of Xuanwu Lake. From the practical difficulty and implementation effect of water environment improvement, the order of water quality improvement effect from good to bad is as follows: the amount of pollutants scheme, degradation coefficient scheme, water diversion scheme, diffusion coefficient scheme. Under the circumstance of limited water diversion, the lake will effectively improve the water quality. Reducing the discharge of pollutants is the fundamental measure to control water environment problems, and water diversion is an auxiliary measure to improve the water ecology. It will become a trend to combine the reduction of pollutant discharge and water transfer for water environment improvement. This paper is of significance for improving the water quality of Xuanwu Lake, and it also provides a scientific method for water environment improvement of water diversion projects.

scholarly journals Study on Characteristics of Nitrogen and Phosphorus Loss under an Improved Subsurface Drainage

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1467 ◽  
Author(s):  
Tao ◽  
Wang ◽  
Guan ◽  
Xu ◽  
Chen ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Nitrate Nitrogen ◽  
Subsurface Drainage ◽  
Ammonia Nitrogen ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Loss ◽  
Soluble Reactive Phosphate ◽  
Reactive Phosphate ◽  
Nitrogen Concentrations

Agricultural drainage plays an effective role in preventing waterlogging and salinity disasters and also is the main transport pathway for agricultural non-point source pollutants into rivers and lakes. Hence, the water quality of agricultural drainage should be a point of focus. In this paper, nitrogen and phosphorus loss under improved subsurface drainage with different filter materials (gravel, layered sand-gravel, mixed sand-gravel, straw) were studied by a three-year field experiment (2016–2018) compared with the conventional subsurface drainage. The pH values, total nitrogen, ammonia nitrogen, nitrate nitrogen, total phosphorus and soluble reactive phosphate were considered. The results showed that the nitrogen and phosphorus concentrations of drain outflow under improved subsurface drainage with gravel filter were larger than that with layered sand-gravel filter and mixed sand-gravel filter. The improved subsurface drainages with layered sand-gravel filter and mixed sand-gravel filter had an effect on reducing the ammonia nitrogen, total phosphorus and soluble reactive phosphate concentrations of the outflow. Meanwhile, the characteristics of nitrogen and phosphorus loss under the improved subsurface drainage with straw filter were different from that with layered sand-gravel filter and mixed sand-gravel filter. For the improved subsurface drainage with layered sand-gravel filter outflow, the ammonia nitrogen, total phosphorus, and soluble reactive phosphate concentrations were about 13%–78%, 38%–63%, 40%–68% less, and total nitrogen, nitrate nitrogen concentrations were 24%–80%,18%–96% more than that under conventional subsurface drainage. Meanwhile, for the improved subsurface drainage with straw filter outflow, compared with conventional subsurface drainage outflow, the percentage changes of the total nitrogen, nitrate nitrogen, ammonia nitrogen, total phosphorus and the soluble reactive phosphate concentrations were about −76%–62%, −77%–78%, −152%–−274%, −103%–−400% and −221%–−291%, respectively. Additionally, in the outflow of all subsurface drainage patterns, there were much higher total nitrogen and nitrate nitrogen concentrations which should be focused on and the agricultural water management should be adopted.

Danish Experience with Emergent Hydrophyte Treatment Systems (EHTS) and Prospects in the Light of Future Requirements on Outlet Water Quality

1990 ◽  
Vol 22 (3-4) ◽  
pp. 65-72 ◽  
Author(s):  
H.-H. Schierup ◽  
H. Brix
Keyword(s):  
Wastewater Treatment ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Reed Beds ◽  
Effluent Quality ◽  
Multi Stage ◽  
Run Off ◽  
Stage System

Since 1983 approximately 150 full-scale emergent hydrophyte based wastewater treatment plants (reed beds) have been constructed in Denmark to serve small wastewater producers. The development of purification performance for 21 plants representing different soil types, vegetation, and hydraulic loading rates has been recorded. Cleaning efficiencies were typically in the range of 60-80% reduction for BOD, 25-50% reduction for total nitrogen, and 20-40% reduction for total phosphorus. The mean effluent BOD, total nitrogen and total phosphorus concentrations of the reed beds were 19 ± 10, 22 ± 9 and 6.7 ± 3.2 mg/l (mean ± SD), respectively. Thus, the general Danish effluent standards of 8 mg/l for N and 1.5 mg/l for P for sewage plants greater than 5,000 PE cannot be met by the present realised design of EHTS. The main problem observed in most systems is a poor development of horizontal hydraulic conductivity in the soil which results in surface run-off. Since the political demands for effluent quality will be more strict in the future, it is important to improve the performance of small decentral sewage treatment plants. On the basis of experiences from different types of macrophyte based and conventional low-technology wastewater treatment systems, a multi-stage system is suggested, consisting of sedimentation and sand filtration facilities followed by basins planted with emergent and submergent species of macrophytes and algal ponds.

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