Hi all,
currently, I am measuring the phosphorus removals (using algae) in domestic wastewaters using hach kit
when I measured the phosphorus amount , the intermediate concentrations were higher than the initial concentration
can anyone please suggest what are the possible reason for this?
Thank you
Dear Colleague,
The phenomenon depends on many factors. What is the exact method and process that is used to measure the others?
What type of algae? The increased concentrations of the binding processes may be affected
Following article might be usefull to see phosphorus fractions in soils of ponds at different age groups.
Article Sediment Quality in Arkansas Bait Minnow Ponds
Dear Ramesh, here is my guess list for your problem:
1. you may want to try test kits other than Hach Lange; sometimes it may just be plain wrong - to our experience.
2. Green microalgae are known to store P in excess of the metabolic need. you observations imply
a. P is excreted by algal cells simillar to PAO (I have not seen it yet)
b. organically-bound phosphorus is released via hydrolysis of organic matter.
I would probably opt for 2b as the more likely answer to your problem, in case there is significant amount of suspended solids in your photobioreactor influent.
Also, the notion "the intermediate concentrations" is unclear to me; do you mean in the effluent?
I may also be able to help more, if you tell me more about your reactor setup, i.e. batch or continuous?
best wishes, Benedek
(Please, push the green arrow if you found this answer useful, else the orange colored - thank you!)
Dear Benedek Plosz, thank you for the answers
I used to measure the concentration of P by taking samples from MFC cathode (microbial fuel cells) reactor (filtered using 0.22 micro M syringe filter) at certain intervals for a duration of 5 to 6 days (batch)
when i measured the filtered and unfiltered samples the total P concentration was similar
even when I suspend the algae into media i used to wash it twice using DI water during centrifugation
so I am wondering what can be the possible reasons
Thank you
Ramesh.k
Phosphorus may be present as inorganic and organic forms. All form must be converted to inorganic form by digestion with nitric acid sulfuric acid mixture andthen the phosphorus will be estimated either via molybdenum blue method (for trace phosphorus) or by molybdovanadophosphoric acid method (Phosphorus content high) colorimetrically. I could not understand the problem of phosphorus analysis/what method is used by the author? Clarification needed further to give any suggestion.
I have worked with the HACH colorimeter for most of my research on drinking and waste water. The gaddet comes with a manual. I would advise you to read the manual and check for interference regarding phosphorus measurements. Then once you pin point what could be interfering with your results you can make adjustments accordingly.
Higher initial concentration than initial is abnormal. Possibility may arise from the presence of water soluble silicate because the method of phosphate and silicate is identical which may add to the phosphate concentration.
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