Reduction of coagulant amount added to activated sludge for phosphorus removal

2004 ◽  
Vol 50 (7) ◽  
pp. 287-292 ◽  
Author(s):  
J. Nakajima ◽  
I. Mishima

Adding coagulant to the activated sludge process is effective in maintaining the stability of phosphorus removal. However, the precise mechanisms of the reaction and behavior of coagulants and phosphorus are not well known. By introducing a new phosphorus removal model (PRM), the behavior of coagulant and phosphorus in the process could be described. The experimental data of the effluent phosphorus concentration and Fe content in the activated sludge agreed with the values calculated by PRM. The amount of coagulant addition to the activated sludge process for phosphorus removal is reduced with the enhanced biological phosphorus removal process. It is suggested that the amount of reduction is determined by using PRM.

1994 ◽  
Vol 29 (7) ◽  
pp. 71-74 ◽  
Author(s):  
G. J. F. Smolders ◽  
M. C. M. van Loosdrecht ◽  
J. J. Heijnen

Experiments have been performed, using a sequencing batch reactor, to examine the effect of pH on biological phosphorus removal in the activated sludge process. The results, which indicate that glycogen metabolism occurs during anaerobic conditions, are useful in elucidating the biochemical mechanisms involved in phosphorus-removal, and have potential implications for systems such as Phostrip.


2016 ◽  
Vol 75 (3) ◽  
pp. 741-751 ◽  
Author(s):  
Yeshi Cao ◽  
Bee Hong Kwok ◽  
Mark C. M. van Loosdrecht ◽  
Glen T. Daigger ◽  
Hui Yi Png ◽  
...  

Mainstream partial nitritation and Anammox (PN/A) has been observed and studied in the step-feed activated sludge process at the Changi water reclamation plant (WRP), which is the largest WRP (800,000 m3/d) in Singapore. This paper presents the study results for enhanced biological phosphorus removal (EBPR) co-existing with PN/A in the activated sludge process. Both the in-situ EBPR efficiency and ex-situ activities of phosphorus release and uptake were high. The phosphorus accumulating organisms were dominant, with little presence of glycogen accumulating organisms in the activated sludge. Chemical oxygen demand (COD) mass balance illustrated that the carbon usage for EBPR was the same as that for heterotrophic denitrification, owing to autotrophic PN/A conversions. This much lower carbon demand for nitrogen removal, compared to conventional biological nitrogen removal, made effective EBPR possible. This paper demonstrated for the first time the effective EBPR co-existence with PN/A in the mainstream in a large full-scale activated sludge process, and the feasibility to accommodate EBPR into the mainstream PN/A process. It also shows EBPR can work under warm climates.


1988 ◽  
Vol 20 (1) ◽  
pp. 81-86 ◽  
Author(s):  
P. Väänänen

Pulp and paper mill wastewaters are nutrient deficient, BOD5:N:P may be as low as 100:1:0.2. Now that purification requirements have been tightened, the activated sludge process seems to be most commonly used treatment method. The conventional activated sludge process requires BOD:P ratios of 100 to 0.6 resulting in a need for P addition and hence in a possible increase in the P-level of the effluent. In Finland and also in some other areas phosphorus removal is of great importance in the prevention of eutrophication of watercourses. There are several methods to control phosphorus level, such as biological phosphorus removal, running of the process under starvation of phosphorus, tertiary (chemical) treatment and simultaneous precipitation of phosphorus. This paper lists possible treatment methods and presents more closely chemical treatment using simultaneous precipitation by ferrous sulphate. The results are based on both pilot and full-scale experiments in two kraft pulp mills. The study showed that phosphorus concentration can be reduced to a level of 1.2 mg/l (tot.P) by adding ferrous sulphate to the aeration basin in activated sludge treatment of kraft pulp mill wastewaters. Ferrous sulphate has, also, a slight positive effect on the sludge properties e.g. sludge settleability.


Sign in / Sign up

Export Citation Format

Share Document