The German African Partnership for Water  and  Sanitation (GAPWAS)  is the  cooperation  project  between the  African Water and Sanitation Association (AfWASA) and the German Water Partnership  (GWP), financed  by the  German  Federal Ministry for Economic Cooperation and  Development  (BMZ) via the  sequa  gGmbH. One of the  goals  of GAPWAS  is to facilitate  joint workshops  as  well as  technical  and  peer  to peer  exchange  and to foster contacts between members  of GWP and AfWASA.

The present  concept contributes to these  goals by combining the  expertise  of German and  African experts  in the  field of water and sanitation in the form of a jointly given interactive workshop  for the  members   of both  associations.  The joint identification of workshop topics and the opportunity to ask questions underscores the  mutual  intention  to address  and share  knowledge  on real  challenges  and  needs  of AfWASA members  and  thus  contribute  to  improving drinking water supply and sanitation including reuse in the region.

The workshop is conducted online for 2 hours and takes place every two to three months. Each workshop is conducted under a specific technical topic with two experts being members  of GWP and  two  experts  from the  membership  or network  of AfWASA.

Ask the experts – 6th  edition

The 6th  edition of the “Ask the experts” series will be organized on 25th April 2023 at 10h00 UTC (Abidjan time) and the topic to be treated  will be:

“Valorising the  end-products  of domestic  and industrial wastewater treatment”.

Wastewater contains essential resources, whose value is increasingly getting  appreciated.  Along with the global acceptance    and   support   for  adopting   the   paradigm   of circular economy,  the  term  ‘waste’water often  is replaced by ‘used’water.  The formerly ‘wasted’  resources  of water, energy and nutrients are getting increasingly expensive and/ or scarce.

Therefore,  today’s  wastewater  treatment  systems   should be planned  from the end: who needs  and commits to reuse the treated  water,  energy  and nutrients? What qualities and quantities are needed?  This information will guide the design process,  i.e.  where  and  how  wastewater is collected  and treated  and corresponding technologies.

The  invited  Experts  will  present  and  discuss  two  cases:

1. Reuse of  excess   sludge  from  industrial  wastewater treatment  in Ethiopia

The  Capital  of  Addis Ababa  has  established   new   industrial clusters. The wastewater of the  textile  cluster is treated  in the industrial park's treatment plant.  The produced  excess sludge still contains  industrial  contaminants and  therefore   is not suitable  for agricultural re-use.  However, a nearby  cement factory is constantly  in need  of fuel. The experts will describe and explain, how a solar drying process is successfully applied to produce   a  sludge   with   90%  dry  matter   ready   to  be   co- incinerated  in the  cement  factory as  renewable energy  fuel. The  project is  enabled    and   financed   by   the   GIZ   facility DeveloPPP.de.

2. Reuse of energy and water from domestic wastewater treatment  in the Germany & Namibia

The Free  Hanseatic  City of  Bremen’s  wastewater treatment plant  has  adopted   anaerobic  digestion  of  its  excess  sludge and  producing  electricity  from  the  captured  biogas  to  power it’s blower  units  for the  activated  sludge  process  as  early  as 1966.   Since   2014,   the    utility   including   the   wastewater treatment  works  –   one   of  the  highest  energy  consumers  in many cities around the globe –are  fully  energy   neutral,   thanks to  a  number  of  additional measures  taken over the years.

The City of Windhoek is situated  in a desert-like  climate  with an average annual rainfall around 360 mm and an annual evaporation   of  3,400  mm.  It  is  known  for  having  started reusing  parts  of its treated  domestic  wastewater for drinking water  production as early as 1969. Over the years, it’s facilities for treating  and  reclaiming  wastewater for potable  use  have been  updated  in an  effort  to  cope  with  a  population  having grown  from  less  than  100,000  inhabitants   in  1980  to  more than 430,000 in 2020.

Besides sharing impressive  facts and figures around  the  reuse of  water,   energy   and  nutrients   in  Bremen  and  Windhoek, the  experts  will share  important   elements of  their  learning journey  from  day-to-day  operation  of treatment plants,  e.g., understanding  the   performance    of  the   plant   at   different steps  of the  treatment process  with  the  help  of taking  and analysing   samples   for   systematic   C-N-P balances   (critical Carbon-Nitrogen-Phosphorous ratio).

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