“I apologise for the dirt,” says Suparjono’s wife nervously as I pull up my trouser legs and tread between the cow pens and duck houses. Embarrassed about her back garden where the waste of seven cows is in heaps amongst the coconut palms and bananas, she tries to lure us away with sweet tea. However, it is precisely this waste material, the fermented by-product of biogas, which Suparjono refers to as his ‘black gold’.

“Smell this,” urges Suparjono clutching a handful of dark brown loam, which has the woody aroma of rich earth. “I used to break my back making compost from manure for my crops, the smell was disgusting and required a lot of work, now I get a tonne of the stuff every two weeks.” He laughs.

The biogas by-product, otherwise known as bio-slurry, is the main focus of a recent programme carried out by the Rumah Energi along with international help and support. The program, known as GADING, complements the Rumah Energi’s BIRU project, which has, since 2009, been facilitating and monitoring the construction of over 17,000 biogas reactors across Indonesia.

The GADING program is funded by the US development agency Millenium Challenge Corporation (MCC), which encourages sustainable development as a means to alleviate global poverty. With research and technical support from the Dutch not-for-profit specialist organisation HiVos, GADING fosters the growth of already existing micro businesses in the agricultural sector. In the province of Yogyakarta, alongside Rumah Energi, this takes the form of biogas and bio-slurry enterprising.

Agus Setiabudi or also known as Tyo, the GADING project Organic Fertiliser Officer, explains that, “Suparjono is a perfect posterboy for our project,every part of his farm benefits from bio-slurry.”

“The fresh bio-slurry provides a breeding ground for worms,” Tyo elucidates, “which his 300-odd ducks forage to produce quality eggs on a daily basis. Every few weeks the dry bio-slurry is collected and used as a rich compost and fertiliser for vegetable crops. The crops are sold on a monthly basis, and some are fed to his cows. Before they are annually sold for slaughter, the cows fully supply the household with cooking fuel, thanks to the biogas reactor and replenish the back garden with fresh bio-slurry again.”

Suparjono eagerly shares that, “my purchases of chemical fertilisers have also been slashed, one bag of fertiliser can cost up to Rp. 250,000 (roughly a quarter of Yogyakarta’s monthly minimum wage) and you need to mix a few different kinds to get all the nutrients you need. Bio-slurry comes already complete in minerals. I’ve probably cut my use of chemical fertiliser in half already.”

That this benefit can be drawn from a waste product (cow dung) gives the GADING project the environmental credibility it is looking for. According to the UN report Livestock’s Long Shadow, livestock manure is harmful to the environment in large quantities, causing eutrophication in rivers and oceans, as well as polluting groundwater and irrigation canals. In the small province of Yogyakarta where cattle number almost 300,000 heads, Suparjono’s is one of very few whose waste will not end up in the waterways.

The relationship between BIRU, GADING, and the estimated 12,000,000 heads of cattle in Indonesia, is promising. Thanks to further research from HiVos, the program is now promoting duckweed, an aquatic plant with six times the amount of protein in soybeans per volume, which can be grown using bio-slurry as a fertiliser.

A 12m3 pond is now under construction at Suparjono’s house. “With duckweed I can cut my purchases of soybean feed for my ducks considerably,” he says, “just one more proof of the benefits of bio-slurry.”

Fishing for facts, I ask him how much he will make from his duck egg sales, he replies “Lumayan”. In English the rough translation would ‘reasonable/okay’, yet in the humble manner of the Javanese, coupled with a noticeable grin, this tends to mean ‘a lot’. Perhaps to others all they see is a dark-coloured waste product, yet for those who venture into Suparjono’s back garden in Bantul, Yogyakarta, it is clear he has already struck gold. (Joshua Parfitt)