The collected materials from the buildings are used in the VVU´s own agriculture e.g. for the plantation of different crops such as maize, cashew, mango etc. It will be proven that also under unfavourable conditions (dry, unfertile grounds) such as in the VVU area the feasible production of foodstuff is possible. For acceptance reasons and for the spreading of the gained experience the collaboration with neighbouring villages and farmers is of major importance to the overall project.

Matter flows in the agriculture



Increasing the efficiency of Agroecosystems
The challenge in crop production is to design a strategy that, despite the extremely harsh environmental conditions, enables the farmer to grow healthy produce in a sustainable way while at the same time makes it possible for the efficient re-use of nutrients and water contained in organic wastes.

Low yields in the region are primarily due to limited water availability and poor fertility of the highly weathered and nutrient depleted soils. Annual precipitation is below 800 mm and varies strongly between years. Since local evapotranspiration, in the magnitude of 1600 mm, exceeds rainfall, the climate is semi-arid. Large scale irrigation is not feasible due to the absence of natural water resources. The farmers’ use of fertilizer is marginal as a result of restricted buying power, frequent supply shortage and ignorance of the plant-nutrient interaction. To ameliorate savannah agriculture, the allocation of water and nutrients to crops is among other duties required.

Water conservation measures at VVU latterly include ditches and mounds for rain water harvesting, terraces as well as tight ridging to prevent uncontrolled rainwater runoff. Further, it is intended to increase the soil’s water holding capacity and infiltration rate through the application of compost.

A key feature of the project is its alternative sanitation technology that allows nutrients and water to be recovered for the use in agriculture. These technologies, including dry urinals and water saving separation toilets, collect urine or urine-water mixture of which both are disinfected by storage and consequently ready to be utilized as fertilizer. Flush water with faecal mater from the separation toilet is deposed either into a biogas plant or peripheral septic tanks. The developing sludge can be used as soil conditioner after undergoing composting treatment. Co-composting of household wastes, yard trimmings and tree-pruning with sludge is due to its independent rain water content. Grey water (from sink, shower, wash basin and laundry) can be re-used to irrigate crops.

Through the implementation of these resource conserving technologies, complex circular flow system is established. The nutrient and the water that enter the campus are collected in shared facilities, processed and used in agriculture. Nutrients cycle back to the cafeteria with the produce. In order to maximize efficiency, losses through percolation and surface discharge must be minimized. The establishment and the routine operations accompanied by scientific evaluation of nutrient flows, pathogen load and acceptance ensure high environmental and hygienic standards.

Diversification within Agroecosystems
VVU has reserved on campus 20 hectares for farming. The division of the area into four productive sections enables a continuous supply of a variety of produce and offers at the same time a wide range of options for the application of sanitary products. Further, diversity of species with specific temporal water demand and dissimilarity in drought-resistance reduces the risk of total loss during times of aridity, while assuming high yi

elds when there is ample precipitation:

·         Agro-forestry, including drought resistant tree species, e.g. cashew, mango, starfruit, guava and oranges, will occupy a major portion of the land. Cultivation of trees allows for the productive use of water supplied by irregular precipitation and constitutes a persisting sink for urine based fertilizer and compost.



·         Sample food crops e.g. maize and cowpea are cultivated under rain-fed conditions during both long and short term rainy season (March to July and September to October). Research concentrates on the investigation of the most suitable model for growing cereals and legumes, fertilized with ecological sanitation products under local conditions.

·         In a fruit orchard, more water demanding species, e.g. paw-paw and banana, are irrigated with grey water and intercropped with pineapples and passion fruit.

·         Vegetable cultivation is supported by irrigation with grey water. Main research will focus on techniques enhancing high water productivity.

Harvested Pawpaw  

weighed Pawpaw (5kg)