ZAAO, a company operating in Vidzeme in a vast area, acknowledges that residents also throw about 2-5% of unsorted waste, including polymer or glass packaging, into the brown containers designed for biologically degradable waste. "There are bags that count as biodegradable, but they are not degradable in this type of biological processing. There's a little mess there sometimes,” said Mārtiņš Niklass, head of the development division of “ZAAO”.
More than 500 biological waste containers are currently installed in Vidzeme. 86 cubic meters of bio-waste has been collected within the month - from the end of February to March 22. They are further processed by the operator to produce compost. It's a multi-month effort divided into three technological stages. The first is mechanical processing, followed by anaerobic fermentation.
"Anaerobic fermentation takes place over 21 days at 55 degrees. This process produces biogas as an adjacent product but basically reduces organic dry matter. Then, in a composting process that lasts at least 33-45 days, we do the stabilization and cleaning of the waste, we reach a temperature of 65 degrees,” Niklass said.
Currently, last year's autumn leaves are composted at the company. The compost produced works for gardens.
Compost from bio-waste is still in the beginning stage, so it can't be said yet how much compost will come from one tonne of bio-waste. Plus, before giving compost to gardeners, it will still be tested.
"Each batch has to undergo laboratory tests to check for heavy metals and eco-bacterium. Testing review is required to tell if use is fully safe,” Niklass said.
If residents are more conscious about sorting, it can become economically beneficial for them. ZAAO claims that it can save up to 40% of waste shipments.
From this year onwards, sorting of biological waste is mandatory, where in addition to existing waste containers, another, brown, should be available. However, this is not yet the case in across most of the capital city and in many municipalities, as no penalties are in place for the absence of the sorting containers.
