INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

calculation of alum dosage for pace to flow at waste water plant.

calculation of alum dosage for pace to flow at waste water plant.

(OP)
i currently work at a waste water pollution control facility.we do approximately dose anywhere from 1300-3300 m3 of raw waste water per day. currently we use from 300-350 liters of liquid alum per day depending on volume of raw. I am wondering what formula would i use to calculate dosage mg/l. we have no way on doing draw downs. We are investigating on getting pace to flow.specific gravity is 1.33. can anybody help?

RE: calculation of alum dosage for pace to flow at waste water plant.

Alum or hydrated aluminum sulphate is widely used precipitating phosphates and aluminum phosphates (AlPO4). The basic reaction is:

Al3+ + HnPO43-n ↔ AlPO4 + nH+

This reaction is deceptively simple and must be considered in light of the many competing reactions and their associated equilibrium constants and the effects of alkalinity, pH, trace elements found in wastewater. The dosage rate required is a function of the phosphorous removal required. The efficiency of coagulation falls as the concentration of phosphorous decreases. In practice, an 80-90% removal rate is achieved at coagulant dosage rates between 50 and 200 mg/l. Dosages are generally established on the basis of bench-scale tests and occasionally by full-scale tests, especially if polymers are used. Aluminium coagulants can adversely affect the microbial population in activated sludge, especially protozoa and rotifers, at dosage rates higher than 150 mg/l. Municipal wastewaters may contain from 5 to 20 mg/l of total phosphorous.

Read more: http://www.lenntech.com/phosphorous-removal.htm#ix...

http://www.ceep-phosphates.org/Files/Document/70/p...

http://www.pca.state.mn.us/index.php/view-document...

RE: calculation of alum dosage for pace to flow at waste water plant.

(OP)
thank you very much for the info. i will do more research on this. Our plant is over 30 years old and are finally upgrading into the 20th century. I appreciate any help on this matter. thanks again.

RE: calculation of alum dosage for pace to flow at waste water plant.

I will give you the formula to figure out the dosing in mg/L. The formula is in metric:


WASTEWATER FLOW (MEGALITER/DAY) X DESIRED ALUM DOSE (MG/L)
LITER/DAY ALUM USED (L) = __________________________________________________________

SPECIFY GRAVITY OF ALUM (KG/L) X ALUM CONCENTRATION (%)


1. Liquid alum concentration is a 48.86% solution (check with your supplier)

2. Liquid Alum Specific Gravity @ 60oF 1.33 (check with your supplier)


RE: calculation of alum dosage for pace to flow at waste water plant.

Unfortunately the space button gets all mangled up when I posted my last reply and as such the formula I gave to you is all screwed up. I have appended an attachment that will clearly show the formula you are looking for. If you can it is best to prepare a spreadsheet and insert your maximum and minimum flows in a day and your maximum and miminum dosage and you will find out the envelope that your metering pump needs to work to

RE: calculation of alum dosage for pace to flow at waste water plant.

(OP)
Thank you for all your help. I figured out the formula on the weekend and is very close to what it should be. I'm glad I found this site and I appreciate all the help I have recieved. Hopefully I can sometime return the favour.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close