Liquid Gold

Scientists in Zambia are developing a toilet that would use human waste as fertilizer for farmers. The toilet would separate urine and the solids to make two different types of manure. The scientists already use one such toilet for their own experimental garden.

From the IPS, writer Lewis Mwanangombe explains how the toilet works.

Kellner and his team at WASAZA are busy pushing on with developing and popularising a latrine that will separate human waste into two components - urine and solid matter, so they can be processed into two different forms of manure.

Kellner is piloting a system called a "fertiliser-producing toilet" which focuses on re-use of solid waste. Such a toilet, once integrated into gardening, will never fill up.

When a user sits on one of the new toilets, the urine will go one way to a storage tank fitted with a compressor and a valve, from where it can be collected for direct use as liquid fertiliser after dilution.

The solid waste will fall into a shallow pit where it will be covered with soil and compacted; it will dry it out and neutralise it before it is ready for use as fertiliser. Any smell is vented out through a pipe.

"The original idea is to enrich the vegetative growth in our immediate vicinity. But it can be sold at prevailing prices. These days dried sludge from sewerage works has a price of ZMK7,500 (around $1.60) per ton," notes Kellner.