Ecological Development of
Valley View University, Accra, Ghana

Water and Nutrient Concept

Since the university plans to increase its enrolment to 2500 people over the next 10 years, there is a need for a water concept, which ensures that the required quantity and quality of water is available on campus and allows a waste water treatment, which is suitable for that number of people, enables cycling of nutrients, respects the requirements of a modern university like VVU and which is sustainable.

The campus is located outside the major urban centre of Accra and is not connected to the municipal water supply and sewer system. This offered the chance to develop and demonstrate sustainable solutions like decentralised waste water management and ecological sanitation systems on campus.
All installations on campus, in respect of the water and nutrient concept, are done with the objective of closing the water and nutrient loop on site. The main aspects of the concept are:

  • conservation and saving of drinking water
  • reduction of waste water
  • retention of rainwater to improve bioactivity
  • ground water replenishment through percolation

Modus operandi - cell structure

Local circumstances like soil conditions, density of buildings, water requirement, quantity and types of waste water, use and number of users vary significantly from place to place. It is therefore impossible to develop optimized general solutions for the entire campus. For that reason it has to be thought of in smaller units, which have similar characteristics. Solutions have to be found for individual areas (= cells), which handle problems in an optimised network: rainwater is to a large extent, left on site, water consumption is reduced and waste water is treated locally.

The organisational structure of the cells supports transparency and responsible behaviour. All cells on campus are connected to each other and build a network.
There are cells e.g. the faculty buildings, which export recovered nutrients to other cells like the agricultural farmland. Whereas the farmland is an importing cell that receives urine, greenery, as well as black and grey water. The guesthouse cell is an autarkic cell, which neither exports nor imports anything. All nutrients from urine and black water are used as fertiliser in the green courtyard. Rainwater is harvested to a large extent and used for toilet flushing, showering, gardening and cleaning.

Basic similarities of the cell concepts regarding the different flow streams are described below.

VVU is Eager Saving Drinking Water

Tab water is a valuable resource that is used, as little as possible, as medium of transport. Also its contamination with harmful substances is avoided. Water consumption is reduced by water saving installations, waterless urinals and flushing techniques with low water consumption.
Depending on the required quality of water, drinking water is substituted either by rainwater or recycled grey water. Rain water from the roofs is harvested and used for flushing, cleaning and watering. After appropriate treatment rainwater can even be used for showering and laundry.

Waste Water Treatment and Nutrient Recovery

Flow streams of different characteristics, such as faeces, urine and grey water are collected separately because they are no longer seen as waste but as resource that should be made available for reuse. For this reason, separating toilets and waterless urinals are used. The flow stream separation allows the application of specific treatment processes and optimises reuse on the agricultural farmland. The recovery of organics, nutrients from human faeces and urine for the benefit of agriculture is achieved by ecological sanitation. As a consequence they help to preserve soil fertility, assure food security for future generations, minimise water pollution and also enable the recovery of bioenergy. These concepts also ensure that water is used economically and is safely recycled to the greatest possible extent and for purposes such as irrigation or groundwater recharge. Appropriate and adequate treatment and handling of the materials throughout the entire process - from collection through to reuse - is required.




1: Urine Tank 


  ContaCt us

   Prof. Dr.-Ing. D. Glücklich    Dipl. Ing. Nicola Fries

   Bauhaus-University Weimar    99421 Weimar