Sunday, September 30, 2012


 The experience that occurs has been developing on our small organic farm of one hectare, Bioagriculture White House, located in the Valley of the River Lurín, Pachacamac district, 35 km south of the city of Lima, Peru.

We grow a wide variety of products such as cassava (manioc), Pope, camote (sweet potato), beans, corn, vegetables, banana, strawberry and various herbs. We also breed cuyes (Guinea Pigs) for meat consumption and recycling of nutrients for the farm.
More than ten years ago, in 1994, we decided to build a biodigestor, Chinese model, in order to take better advantage of the manure produced by the guinea pigs from a farm which at that date had a population of 600 animals. Until that date, the Guinea pig manure was mainly used as organic fertilizer, already out directly or mixed with the stubble or crop residues for the preparation of compost, manure produced under aerobic conditions.

Currently the population of Guinea Pigs fluctuates between 900 and 1,000 units and produces approximately three tons of manure per month (36 tons per year). It is from this animal biomass produced in the farm - which adds plant biomass (crop waste) - which promotes recycling. Through these processes, we can not only produce bioabonos, in liquid or solid form, but also biogas.

The process that is performed using the bio-digester is somewhat a mirror of what happens in nature when the biomass buried for millions of years is decomposed under anaerobic conditions and produces a considerable deposit of natural gas or biogas.

The bio-digester of White House Bioagriculture has a capacity of 10 cubic meters. The central Chamber has three holes that are connected: a central hole that only opens once a year, for the initial loading and unloading; a side port connected to a tube that goes near the bottom of the camera and that serves the regular feed, and finally a third hole attached to a side Chamber where they exit the liquid bioabono or biol.
Load initial or bottom loading which feeds each year the bio-digester is constituted by a precompost that, for White House Bioagriculture, is prepared from Guinea pig manure and Corn Stover.

A ton of this precompost, which is three to four weeks of preparation, and with a temperature between 50-55 ° C, is introduced by the central mouth and mix with 200 litres of rumen or crap coming from the stomach of livestock cattle newly slaughtered; This material is obtained from an abattoir or slaughterhouse in the area, only once a year and, generally, for free because it is considered scrap material. The rumen or basofia contains a high load of anaerobic microorganisms responsible for the process of fermentation and the production of biogas, including methane.

Then add water up to a volume of approximately eight cubic meters, leaving the two cubic meters remaining for the storage of biogas in the upper part of the central Chamber of the bio-digester. Immediately, is to close the center hole with a heavy lid on which even stones are placed to prevent that it is lifted by the pressure of the produced biogas.

Each week feeds the bio-Digester with a mixture of manure cuy and water in proportion of 1: 3, allowing us to have one sufficient volume of gas for the entire week.

After a year of the initial feeding of the bio-digester is downloading, obtaining the solid bioabono or biosol. In the original model, discharge is done through the central hole, which is very uncomfortable and complicated. To facilitate the discharge of the biosol we have made a modification to the original design of the bio-digester, which consists of the construction of a side window, overlooking an adjacent to the bio-digester atmosphere, and is sealed with a lid of galvanized iron, secured with bolts.

The bio-digester of White House Bioagriculture comes running efficiently since it was built 10 years ago and thanks to biogas production we have been able to save significantly the cost of electric power in the House.
Once the biodigestor begins to produce biogas (at the five or six days in summer), this energy can be used as fuel in the kitchen or for lighting directly by gas lamps.

 If there is an electrical generator that runs on gasoline, following modification of the carburetor, you can do function with biogas (methane) to produce electricity.

On the other hand, we get steadily liquid bioabono or biol, which is not only an excellent organic fertilizer for our crops, but its contents of phytohormones, is a valuable enabler of growth and flowering of the plants, especially fruit trees.

The third product of the bio-digester is obtained annually to perform the download, when collected the solid bioabono or biosol, which is an excellent fertilizer for crops.

Given the growing interest by the bio-digesters, each year, when are we going to download the bio-digester and reload it, we offer courses with the motto "learning by doing", through which participants can learn in a very practical way how a bio-digester is built, how works and how it is downloaded and reloaded.

Without a doubt one of the central attractions of the farm is the bio-digester operation observed as part of the work of recycling we do using all waste that the farm produces.