Regarding parameters for UASB reactor Design for food waste leachate

[abhivmairal]

Dear All,

We are designing pilot scale UASB reactor to produce biogas from our canteen food waste leachate. The COD in leachate varies from 20000 mg/l to 40000 mg/l. Typically UASB reactor can go upto OLR's of 10-20 kgCOD/m3/day.

1) Does anybody have any experience what upflow velocity should be considered for diameter selection for UASB reactor ?
2) How to calculate the SRT for canteen food waste leachate and what is the typical range of SRT for food waste leachate.
3) Does anybody have design of inlet distribution system?

Regards
Abhijeet

 

[ashtree]

Here are a couple of numbers to start off

Hydraulic residence time in UASB is typically inthe range of 3-8 hours.
You will probably need 0.6to 0.9 m/hr upwards velocity to keep the blanket in suspension.
You are at or way above the maximum recommended loadings for COD/m3/day so i would suggest you maximise the HRT to 8 hours.

If you know your flow rate, using the above numbers then you should be able to start thinking about dimensions.

Calculating SRT is easy. It is the average time that solids spend in the UASB. The easiest way of calculating this is UASB volume/sludge wasted per day=SRT (days)

However I think you are asking what will the SRT be for food waste leachate. That may well have to be established by trial and error, because optimum SRT is very waste and site specific.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"