Heading East - Planted Drying Beds

Saturday 31st August - Sunday 1st September

After a day off in Dhaka we headed out to Lakshmipur ("lock-he-pur") on Saturday to look at a planted sludge drying bed they've had up and running for a few months.  Construction started in February (2013) and was completed in March/April.

This is a project supported by DIFID.  They are collecting the sludge from 4 wards, each of around 50,000 households, and the site receives a delivery 2-3 times a week. Households pay 1000tk/ 2m3 (about £8 or $13) for the emptying service, and this goes to the Municipality, who then pay contractors who coordinate sweepers, drivers and the vacutug(s) to do the actual collection.

They expect it will take 8-10 years to fill both drying beds.  They are anticipating being able to dig out the material at any point and use it for fertiliser.

Planted drying bed on the right, discharging wastewater into the polishing pond on the left.

Wastewater drains through the bed, and its sand filter in the base, before going into a polishing pond alongside.  They are testing the effluent for BOD and COD prior to discharging it from the polishing pond into a nearby watercourse.  Apparently the pond fills quickly during the rainy season, and they have to pump it out - it does not 'naturally' drain anywhere.

Sludge being delivered via vacutug - you can see it pouring into the bed on the right in the middle of the photo

 The team have had few challenges in the construction and operation phases - it seems the Municipality understands the need for the facility and its benefits.  The main problem they said they faced was acquiring the land.

The main objective of the facility is to provide environmental protection - collecting sludge that would otherwise be hazardously dumped.  The ability to collect and use fertiliser is an additional benefit, but not the main reason for it's construction.

It was really useful to see this solution to large scale sludge management in practice.  Contrary to some of the literature I've read on planted drying beds, there were no noticeable odours or flies, and even the heavy rain did not seem to be causing significant ponding on the surface of the bed.

Close up of the planted drying bed surface

We had a long, long drive back to Dhaka, trying a different route to avoid the centre, and using roads that varied from good to barely-passable.

View of the Indian border...and HILLS! (in India...)

Still, we made it by about 9pm; time for a quick check-in, unpack, and repack for our 8am flight to Jessore tomorrow.

View of some of the heavy industry somewhere outside of Dhaka