Project Results: 

The water supply of the provincial town Xai Xai is based on groundwater. The boreholes are located in the inhabited dune area and suffer from increasing Nitrate levels due to leakage of Nitrate from the pit latrines and septic tanks. Some of the boreholes have already been closed off. In this project a pilot is done in an area of 1 km2 around one of the affected boreholes. People living in the area got new or rehabilitated toilets with sealed pits. The original idea was to have urine diversion at the toilet, but this idea was later abandoned. The sludge from regular pit emptying is brought to the waste water treatment site, where a modern waste water digester is built. The thick sludge from the digester is composted, while the liquid is planned to be used for struvite production. As long as the Struvite system is not in place, the liquid is directly used on the fields of the neighboring Agricultural Cooperative.

The project encountered many challenges, ranging from the cooperation with partners and the communities, the management of expectations, complications with the installed technology (esp. related to the power supply), transport of the Struvite installation from Namibia and the subsurface Nitrate monitoring. It did not help that the project coordinator was based in the Netherlands. Nevertheless many of the issues were solved and at the end of the project everything was in place except for the Struvite machine. The management was handed over to a Private Enterprise, having interest in getting acquainted to the Fecal Sludge Management business.

Attempts are made to measure the impact of the interventions on the Nitrate levels in the soil and groundwater. The monitoring will continue, as the impacts might only become visible after a longer time span. To speed-up the installation of the toilets, an uptopping was provided. Final project budget has been € 300,622 of which € 216,023 was provided as a subsidy by Aqua for All/VIA Water.

Key results

  • Sealed pits in the pilot area (>100 toilets) and a collection service in place
  • Sludge treatment plant of 4 m3/d capacity in place (Afmitech/Bever III)
  • Composting unit
  • Transfer to Municipality and Private Enterprise Collins Ltd

Tips for the future

  • Have permanent presence of a coordinator in this type of social innovation projects
  • Cultural elements are very important success factors for a project that requires full commitment of the community and change of behavior
  • Have better guarantee/commitment of future operators right from the beginning

Potential for growth
This is the first fecal sludge treatment facility outside of the big cities. The interest of the Private Enterprise shows that there is potential to learn from this experience to be applied elsewhere.

Project partners
SWS, Wetterskip Fryslan, FACE (former FUSP), Xai Xai Municipality, FIPAG, ARA-Sul (and later Afmitech and Collins Ltd)

October 2015 – March 2019


Xai Xai, Mozambique
Xai Xai,
Xai Xai,


Different Frisian organizations are involved in sanitation in Mozambique. In the Frisian Urban Sanitation Program (FUSP), the province of Fryslân, Water Board Fryslân, Vitens and most municipalities in Fryslân cooperate and support local authorities in Mozambique to improve sanitation conditions. SWS will cooperate with FUSP to achieve multiple goals in sanitation related topics in Xai Xai, one of the 8 cities where FUSP has been active. Xai Xai is located in the south of Mozambique. The cooperation with SWS is relevant for FUSP because the project described in this proposal will contribute to the protection of groundwater, improved handling of waste from latrines and recycling of nutrients from waste streams. In Xai Xai, FUSP has a partnership with the municipality of Xai Xai to produce compost from organic waste. This started in 2013 and also incorporates faecal sludge in the compost. As a next step SWS and FUSP seek to reuse urine by extracting the mineral struvite, which is a valuable fertilizer for agriculture. When Nitrate can be extracted as well, the amount of nitrate leeching into the aquifer (which is used for extraction of drinking water) can be reduced significantly. SWS International has developed a struvite(fertiliser) recovery system and seeks a project to test the system in a real-life situation. Together with electricity generation from urine it probably will provide a sustainable and viable system for cities which depend on groundwater for drinking water supply (like Xai Xai). By collecting urine and processing it, a significant reduction of the groundwater quality problem can be achieved. For SWS, participation in this project will give the perfect opportunity to see whether the reactor will work in full scale as expected. During the pilot, it will be tested on operational reliability and on repeatability of the output. Furthermore, the demand for struvite and the market for it will be investigated, to ascertain whether the concept is economical viable. The marketing channels are defined and integrated in the project. The project will also give the opportunity to test electricity generation from urine as an additional step to use waste streams as efficient as possible. These techniques will contribute to a safe and responsible treatment of liquid waste and will offer the municipalities a sound alternative for the often-practiced dumping of waste material. The sewage system and most septic tanks in Xai Xai now drain into the Limpopo river which causes locally severe water pollution and increased health risks for the residents. Moreover, the common use of non-sealed pit latrines has caused a worrying rise of nitrate concentrations in the aquifers. The importance of the kind of projects as proposed here, which tackle these issues in an economically viable way, cannot be overstressed since alternatives such as new well fields or treatment would cost millions of euros. With the project described in this proposal SWS International hopes to attract positive feedback and awareness on the importance of such projects in third world countries

Project Plan

The project will try to address two major problems: the poor sanitation in low income areas and the reduction of nitrogen inflow into the aquifers. SWS has developed a plan to tackle both problems simultaneously. It will also bring along positive side effects. The system is mainly composed of two parts which are the replacement of latrines and the collection and treatment of urine and faeces. 1- Replacing the currently used latrines: - The latrines that are now used in Xai Xai are assumed to be the main cause of the rise in nitrate levels in the groundwater. The non-sealed pits under these latrines must be replaced with sealed ones, which prevent percolation of urine into the groundwater. The design for these new pit-latrines has already been tested by SWS in Namibia. These latrines are composed of a simple plastered hole in the ground that will hold the faeces and a neighbouring septic tank for holding the urine. To separate the faeces from the urine a Xipoti type toilet with urine diversion will be used. 2- Collecting the urine and faeces: - A urine/faeces collecting plan will be made to assure a steady flow of urine/faeces for the treatment facility and also to avoid overloading the latrines. 3- Urine/faeces treatment: - A struvite reactor is used to extract struvite from urine and in the process drastically lowering the nitrate levels in the urine. The struvite can be used as a fertilizer for agriculture. - The leftover fluids from the process will be denitrified by converting its remaining nitrate contents into nitrogen gas. This way the water that is leftover can be discarded more safely into the environment. (denitrification) - The faeces will be dried and turned into compost which can also be used as a fertilizer.

Target group

Initially, the pilot will focus on the 250 households in the low income area around the borehole with regard to sanitation. The Borehole is used for the central water supply of Xai Xai and will affect many more people if nitrogen levels would drop. The struvite and manure will be nprocessed and managed by the Agriculture Cooperative.


The project has a pilot character, but is aiming at sustainability in several ways: 1. sustainability of existing boreholes to avoid increase of Nitrate levels 2. sustainability of the system by including value to waste approach and including private partners 3. sustainability of the sanitation service by inclusion in the Municipal system

Overview of Goals

1 - Stabilizing and reducing nitrate levels in the water of the test borehole. 2 - Increasing the overall sanitation level in the surrounding area of the test site. 3 - Creating a struvite and compost business to stimulate the recycling of urine/feces and to increase employment. 4 - Avoiding high costs for implementing water treatment systems or new boreholes. These objectives will be translated to objectively verifiable goals and their corresponding activities. These activities are spread across three phases. Each phase must be completed successfully to proceed with the next phase.

Results and indicators

  • inception phase