Making bio-gas at home from food scraps is now becoming an easily affordable reality. After
seeing a model of the Homebiogas device on display at the June 26-27 Cleantech Israel 2018 conference and exposition in Tel Aviv, I paid a July 10 visit to the company’s headquarters in Beit Yanai Israel, to inspect a working model of the appliance that makes usable methane based bio-gas in one’s own backyard using a combination of manure, food scraps and other organic material.
Roy Barzam, Homebiogas’ US sales manager (photo), took me on a tour of their facilities, at which several bio-gas appliances were in various stages of bio waste processing and operation. “The process of converting organic wastes into bio-gas is known as anaerobic digestion
in which bacteria and other micro-organisms breakdown the organic material without being exposed to air. This is different from composting, in which the organic material
is exposed to air” he said. This anaerobic breakdown process is what produces the mostly methane bio-gas that is then stored in the appliance for later home use.
The Homebiogas appliance, made almost entirely of PVC and polyprophane plastic materials, weighs only 23 KG “in the box” when delivered with a set of assembly and operation instructions. When completely ‘charged up’ with horse or cow manure (the best fertilizer for producing suitable bacteria for the breakdown process), water and food scraps, the appliance weighs as much as 1.5 tons. The entire bio-gas production process takes several weeks, Roy added, pointing to an appliance still in the bio-gas production process (photo).
Once the Homebiogas appliance is delivered to a customer, the set-up and preperation process is as follows:
After unpacking assembling on a dry, flat surface, around 100 KG of horse or cow manure is fed into the appliance’s intake inlet to create the needed bacteria. After a 3-4 week time period, organic waste such as vegetable and fruit, meat and dairy scraps (including bones) are fed into it. Up to 12 liters of “kitchen wastes” per day can be added via the intake “feeding tube”. Water is also added along with food wastes (up to 1200 liters).This is done until the water volume and food waste volumes are more or less equal.
“The manure does it all to create the bacteria for breaking down the food wastes”, Roy says. He also pointed out a capped outlet pipe from which filtered liquid fertilizer, a byproduct of
the biogas production process, is removed. What remains from this process is a sludge that accumulates at the bottom of the appliance and is eventually removed.
Roy also showed a “bio-toilet” in operation ( above photo)in which human wastes are fed directly into a Homebiogas unit. The resulting fertilizer would not be suitable for fertilizing food crops, but can be used for fertilizing trees flowers, grass, etc. “Bio-toilets, which are like those used in boats and campers save water, due to their unique pumping systems” Roy adds.
Since Homebiogas was founded in 2012, some 3000 biogas appliances have been sold to customers in more than 90 countries. “We advise using our appliance in warmer climates where temperatures are at least 20 degrees Celsius during the daytime. Otherwise, a heating device must be used to keep the processing bacteria alive and functioning properly” , Roy said.
Due to the much lower gas pressure for the created bio-gas in its 700 liter storage compartment, the Homebiogas appliance is much safer to use than conventional LP gas; and has been certified safe to use by Israeli governmental authorities. The amount of daily bio-gas produced is enough to power a one burner gas unit for up to two hours. One of these gas burners is included with each appliance.
As to the future: “We are developing larger models for use in schools and other facilities. They will be much larger than the standard home model – as much as 5 times larger”, Roy said.
More about biogas from biomass and food scraps: