The Mechanism and Influence Factors of Struvite Precipitation for the Removal of Ammonium Nitrogen

2011 ◽  
Vol 189-193 ◽  
pp. 2613-2620 ◽  
Author(s):  
Hai Ming Huang ◽  
Qian Wu Song ◽  
Chun Lian Xu

Struvite (MgNH4PO4∙6H2O) is an insoluble double salt. It can precipitate in places such as pipes, aerators and pumps, which could lead to substantial problems influencing the normal operation of wastewater treatment equipments. At present, removal of ammonium nitrogen from various wastewaters by the formation of struvite has been widely investigated. This paper reviewed the research and application efforts concerning the treatment of ammonium nitrogen by struvite precipitation, which were obtained at home and abroad in recent years. The mechanism and influence factors of struvite precipitation for ammonium nitrogen removal were discussed. Additionally, the problems that still should be resolved and the research directions in future were pointed out.

2004 ◽  
Vol 50 (7) ◽  
pp. 97-103 ◽  
Author(s):  
A. Harri ◽  
J. Bosander

At Himmerfjärden wastewater treatment plant, a fluidised bed reactor for nitrogen removal has been operated since 1997. Despite its small footprint, the system enables a far-reaching nitrogen removal. The current nitrate reduction in the reactor is 95%. The reduction of total nitrogen at the wastewater treatment plant is 80-90% at normal operation. The concentration of nitrate in the effluent is easily controlled by changing the dose of carbon. As part of a series of full-scale experiments, the plant has, for the last two years, been operated without denitrification for a couple of months during spring/summer, in order to benefit a favourable N/P-ratio in the recipient and to counteract the growth of nitrogen fixing blue-green algae. When resuming the dosage of carbon, full denitrification was re-established in about two weeks. Important factors to take into consideration when operating the fluidised bed reactor are the abrasive characteristics of the carrier material (sand), the increased concentration of suspended solids in the effluent, and the importance of a suitable N/P-ratio in the influent, as lack of phosphorus might cause an uncontrolled microbiological growth.


2013 ◽  
Vol 838-841 ◽  
pp. 2739-2744
Author(s):  
Shuang Zhao ◽  
Cui Ping Wang

A novel process for improving the energy use and treatment efficiency of the biological nitrogen removal process, up-flow microaerobic-oxic (M/O) process which is composed of up-flow micro-aerobic and aeration was proposed based on a laboratory scale for domestic wastewater treatment, the dissolved oxygen (DO) in up-flow micro-aerobic was in the range of (0~0.5) mg/L. The M/O process performance under different hydraulic retention time (HRT) and Internal return ratio (r) was investigated. Under the optimal conditions, the average removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and ammonium nitrogen (NH4+-N) were 89.1%, 64.1%, and 96.6 % with effluent concentrations of COD, TN and NH4+-N less than 50,15 and 8mg/L, respectively. The distribution of sludge particles diameter and microbial activity of activated sludge were also measured, the mean particle diameter was in the range of 180~250μm and the SOURT was 13.11 mgO2/(gMLVSSh). Up-flow micro-aerobic (M/O) reactor has the advantages of more stable performance and better resistance to the load shock than the conventional A/O process within continuous running period of 130 days.


2011 ◽  
Vol 63 (12) ◽  
pp. 2838-2845 ◽  
Author(s):  
D. J. I. Gustavsson ◽  
J. la Cour Jansen

Biological treatment in wastewater treatment plants (WWTPs) is a source of nitrogen oxides (N2O, NO and NO2) emitted to the atmosphere. Aerobic ammonia-oxidising bacteria (AOB) have been suggested to be the main source of these emissions. In a full-scale sludge liquor treatment plant at Sjölunda WWTP, it was shown that significant emissions of N2O, NO and NO2 do occur. The plant is operated with nitritation alone, which gives an environment enriched in aerobic AOB. During normal operation, emissions of N2O, NO and NO2 were found to be 3.8%, 0.06% and 0.01% of the ammonium nitrogen load. The N2O emissions were larger than the recommended estimated figure of the Intergovernmental Panel on Climate Change (IPCC) for a complete wastewater treatment plant. The N2O emissions correlated positively with the length of the previous anoxic period, i.e., settling and decantation, and with the ammonium oxidation rate. The NO and NO2 emission profiles were similar and dependent on ammonium oxidation and DO level, but the NO2 concentrations were always lower.


1990 ◽  
Vol 22 (3-4) ◽  
pp. 211-216
Author(s):  
Niels Skov Olesen

In some areas of Denmark nutrient removal is required even for very small wastewater plants, that is down to 500 pe (pe = person equivalents). The goal for the removal is 80% removal of nitrogen and 90% removal of phosphorus, or in terms of concentrations: 8 mg nitrogen/l and 1.2 mg phosphorus/l. The inlet concentrations are typically 40 mg N/l and 10 mg P/l. The paper presents the results from two such plants with a capacity of 800 pe. Phosphorus removal is made by simultaneous precipitation with ferrous sulphate. Nitrogen removal is carried out using the recirculation method. Both plants were originally rotor aerated oxidation ditches. They have been extended with a denitrification reactor and a recirculation pumping station. At present both plants have been in activity for about 3 years and with satisfactory results. Average concentrations of nitrogen (summer) and phosphorus is 7 mg/l and 0.9 mg/l respectively. Nitrogen removal seems to be a practical solution on these small plants. It is,though, sensitive to temperature and highly oxidized rain water. Phosphorus removal seems to be an easily run and relatively non-sensitive technique at least when using simultaneous precipitation.


1995 ◽  
Vol 32 (7) ◽  
pp. 135-142
Author(s):  
E. Görgün ◽  
N. Artan ◽  
D. Orhon ◽  
R. Tasli

Effective nitrogen removal is now required to protect water quality in sensitive coastal areas. This involves a much more difficult treatment process than for conventional domestic sewage as wastewater quantity and quality exhibits severe fluctuations in touristic zones. Activated sludge is currently the most widely used wastewater treatment and may be upgraded as a predenitrification system for nitrogen removal. Interpretation of nitrification and denitrification kinetics reveal a number of useful correlations between significant parameters such as sludge age, C/N ratio, hydraulic retention time, total influent COD. Nitrogen removal potential of predenitrification may be optimized by careful evaluation of wastewater character and the kinetic correlations.


1992 ◽  
Vol 25 (4-5) ◽  
pp. 203-209 ◽  
Author(s):  
R. Kayser ◽  
G. Stobbe ◽  
M. Werner

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.


1999 ◽  
Vol 39 (6) ◽  
pp. 191-198 ◽  
Author(s):  
Timothy J. Hurse ◽  
Michael A. Connor

In an attempt to gain a better understanding of ammonia and nitrogen removal processes in multi-pond wastewater treatment lagoons, an analysis was carried out of data obtained during regular monitoring of Lagoon 115E at the Western Treatment Plant in Melbourne. To do this, a contour plot approach was developed that enables the data to be displayed as a function of pond number and date. Superimposition of contour plots for different parameters enabled the dependence of ammonia and nitrogen removal rates on various lagoon characteristics to be readily assessed. The importance of nitrification as an ammonia removal mechanism was confirmed. Temperature, dissolved oxygen concentration and algal concentration all had a significant influence on whether or not sizeable nitrifier populations developed and persisted in lagoon waters. The analysis made it evident that a better understanding of microbial, chemical and physical processes in lagoons is needed before their nitrogen removal capabilities can be predicted with confidence.


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