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close this bookBioconversion of Organic Residues for Rural Communities (UNU, 1979)
close this folderThe combination of algal and anaerobic waste treatment in a bioregenerative farm system
View the document(introduction...)
View the documentIntroduction
View the documentAlgae production on organic wastes
View the documentThe bioregenerative farm
View the documentReferences
View the documentDiscussion summary

Introduction

The concept of the bioregenerative farm has been introduced to describe a model farm in developing countries (that can easily be applied in developed countries as well) where domestic and farm wastes are recycled and recovered to a maximum level through a chain of biological processes and farming practices, thus reducing input of cash-intensive items such as proteinaceous animal feed, irrigation water, fertilizers, and fuel, while increasing cash-intensive outputs such as animal products, fish, and cash crops (1). Enhancing sanitary and health conditions by proper waste management is an important fringe benefit of the bioregenerative farm concept, though not always fully appreciated. Once the concept of self-reliance in the farming community has been accepted, other non-biological resource recovery techniques, such as utilization of solar and wind energy, can be introduced as well.

The principal bioregenerative process discussed in this paper involves the intensive growth of algae on wastes, with an emphasis on its combination with anaerobic bacterial processes. Pond fish production can be tied to the bioregenerative scheme, as can other, though less well established, biological systems, such as nitrogen fixation by the blue-green alga Anabaena azolla, which is symbiotically associated with the Azolla fern in rice paddies, replacing commercial nitrogenous fertilizers (2).

All biological processes involved in the bioregenerative concept are well established in nature's cycles of organic matter degradation and primary productivity, and in the food chain. Within the bioregenerative farm they are, however, intensified many-fold and are designed to increase their biomass growth rate, and hence their activity, by optimizing the physical conditions and the growth-limiting factors such as substrate and nutrient concentrations, light intensities (in the case of algae), retention time, etc.

Some of the components of the bioregenerative farm considered for application in rural regions of developing countries stem from results and experiences accomplished by using sophisticated techniques, such as algal systems for life-support space applications (3), for food production (4), for treatment of municipal wastes (5), etc. The development of the Gobar anaerobic fermenter for rural areas in India benefited from decades of development of heated, mechanically mixed, continuous anaerobic digesters of municipal waste-waterborne sludges

Some famous racing-car manufacturers who later turned to the production of less complex, popular, inexpensive cars have learned that simple technologies can benefit greatly from experience with complicated ones. Or, as illustrated by an advertising slogan of a large US corporation that was involved in the space programme, but has now turned to manufacturing consumer products as well: "... it took putting a man on the moon to produce a reliable coffee-maker ...."

Indeed, a significant part of the information that is being used now to develop the bioregenerative farm concept comes from two major comprehensive projects carried out at the Technion Environmental Engineering Laboratories in Haifa, planned for communities in industrialized countries using more sophisticated techniques and methodology The first is the joint Israeli-German project on Combined Algal Municipal Waste Water Treatment, Water Reclamation, and Animal Protein Production (6), and the second is the project on Utilization of Agricultural Wastes for the Anaerobic Production of Biogas, which has been sponsored by the Kibbutz Industry Association of Israel since 1975, and whose goal is to accomplish a maximum degree of self-reliance in energy through biogas production and utilization in the kibbutz-type communal, highly modernized farming system (7, 8). The relevant information from both projects, together with results of experiments directly related to the bioregenerative farm in developing countries, are discussed in this paper.