Solid waste is an increasing problem in Vietnam. It is one of the fastest growing sources of greenhouse gas emissions in the country, with most emissions being from the decomposition of organic waste. There are many initiatives being implemented elsewhere in Asia to manage the various waste streams, and one of the most successful so far has been composting of organic waste. There is great potential to implement similar projects in Vietnam.
Potential projects include:
Household composting, which offers the benefit of not needing to transport organic material to a central location. It allows the compost to be used by the household for growing food or ornamental plants, and so provides nutrient-rich fertiliser for very little cost. A system that requires few materials and is very efficient has been introduced to Thimphu in Bhutan. A cardboard box, wood box or plastic crate is used as container, to which is added rice husks, rice bran, yeast, yogurt or curd, sugar, kitchen waste and another source of micro-organisms such as forest leaf litter if available. The first step is to ferment the rice husks and rice bran base and then add the mixture of yogurt or curd, sugar, yeast and allow it to ferment for a few days. The other organic material is then added to the base material and the decomposition process begins. It only needs to be turned a few times to ensure it remains aerobic and generates heat evenly.
(Acknowledgement: Thimphu Thromde Environment Department)
Centralised composting, allows large volumes of material to be processed and so is a feasible option where there is both a large supply of organic material and significant demand. Research carried out by the International Water Management Institute (IWMI) has demonstrated an improvement in urban sanitation and an increase in farm productivity through improved soil fertility. The Fortifer Compost Plant developed by IWMI processes human and other organic waste into powdered and pelletised nutrient-rich compost. Sewage and animal wastes are firstly dried on beds of sand and then mixed with food waste and sawdust. The heat generated as it decomposes kills any pathogens in the waste. The resulting compost, which meets WHO safety standards for reuse of human waste, has been shown in field trials to improve the yield of grain and vegetable crops.
No external funding is likely to be needed