Bulawayo, Zimbabwe: Application of recycled water in the irrigation of urban open spaces (Parks & Stadiums)

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City: Bulawayo
Country: Zimbabwe
Categories:         Living Green for Water IconLiving Green for Climate Change Icon
Award: Certificate of Merit

* This case study was written by the city and has not been edited by AIPH

Initiative: Application of recycled water in the irrigation of urban open spaces (Parks & Stadiums)

City of Bulawayo Greener City initiatives – Wastewater Reclamation

The scope of the Greener City Initiative is to reduce the impact of activities undertaken by people on the physical environment. City of Bulawayo aims to achieve this goal by number of projects that have been running since the establishment of the Council. Wastewater reclamation is one way, and this document will dwell mostly on the reclaimed water and its use to promote a greener city/green space in an urban environment. The City of Bulawayo is in region 5 of the country which generally receives low rainfall and as such consists of seasonal rivers. As a result, there is a shortage of water as a resource, thus considering this most of the greenery in the city is due to the steps and initiatives by the City Council to preserve and promote green spaces in the city. One of the explored avenues as a city has been through wastewater recycling. The city was planned in such a way that there are two networks in the city, one for transporting potable water and the other system which convey treated water from the wastewater treatment plants for greening the city, i.e. water the football pitcher, parks withing the city, watering the trees planted around the city centre and for landscaping.

Sewer Water Recycling or Reclamation Programs

Within the boundaries of the City of Bulawayo, there are 11 sewer treatment plants strategically located to service the city, mostly medium and high-density suburbs where installation of septic tanks is not possible. For Low density suburbs they are required to install septic tanks systems which naturally treat the domestic effluent to reduce its pollution power on ground water and such ecosystems. The sewer treatment Plants are Thorngrove, Waterford, Luveve, Magwegwe, Southern Areas Sewer Treatment Works (SAST) and Aisleby Treatment Works. It is from these treatment works where reclaimed water is taken back for greening the city.

Reclaimed Water Uses

At each of the aforementioned treatment plants domestic effluent is treated by a number of processes (namely pond system, Biological Removal System, and trickling filters) to meet guidelines as set by standards set by the Environmental Management Agency (EMA) to ensure that the effluent from the plants does not impact the environment negatively. The reclaimed water is then used for a number of different applications.

Recycled water is used to water most of the city’s recreational parks and grounds to give the city its great aesthetic looks and achieving a greener city initiative. The Centenary Park, City of Bulawayo Tower Block landscaping are such places that are kept green by the continuous flow of recycled water from treatment works. Municipality owned stadiums such as Barbourfields and Luveve are irrigated using reclaimed wastewater from the treatment works.

Addressing the urban challenge

Breadth of the issue – How are the problem(s) that are being tackled by your initiative affecting citizens/local businesses or a significant component of the local wildlife?

The trees planted yearly on tree planting day grow to become habitation for birds and other living organisms. Because the trees have densely grown in the CBD it makes the business district cooler for good working environment for people.

Depth of the issue – How seriously are the problems being tackled by your initiative impacting the life of the citizens/businesses/wildlife concerned?

Sewage treatment ponds that use a variety of mechanisms that include aerobic, anaerobic and facultative micro-organisms for the removal of harmful substances from sewage by passing the effluent through a series of ponds dug in a wide-open space and no chemicals are used in this treatment process. This method of treatment is used at Cowdray Park and Magwegwe North

Thorngrove Reclaimed water is supplied to respective consumers through the 8 inch and 15-inch lines. The 8 inch line supply the Barbourfields stadium, Parks Nursery, Save our Souls (SOS) Primary School, and the Thorngrove sewage plant while the 15 inch line feeds Centenary park, water workshops, Gifford high school and Zimbabwe International Trade Fair (ZITF) just to mention a few places.

Waterford reclaimed water was supposed to be used for watering the golf course but they required high quality effluent and a reclaimed water plant was included and also a provision to augment the reclaimed water with borehole water which is about 500m from the plant.

The power of plants and natural ecosystems to deliver benefits

How is the initiative shaped by scientific evidence of the potential for plants and natural ecosystems to deliver benefits?

Reclaimed water from wastewater is known from laboratory tests to contain a high amount of nutrient content in the form of phosphates, nitrates etc hence its application in the irrigation of plants is beneficial to plant. The city has a fully equipped laboratory for conducting tests for chemical contents in the reclaimed water before it is discharged to the environment.

The use of reclaimed water reduces the use of artificial fertilisers to aid the growth of plants and ensure City greenery.

Sludge which is mostly derived from faecal material which is also rich in nutrient content hence its use as a biofertilizer to aid the growth of plants without any adverse effects to the natural ecosystems.

How has the city exploited the potential of plants and associated ecosystems to deliver more than one benefit?

There are numerous benefits brought about such as the increased productivity of farm produce making availability of agricultural produce throughout the year.

The produce from the selling of reclaimed water generates income to City Council help fund the reclamation programs making it a sustainable investment.

The green spaces have been good places for weddings and providing good venue for most social activities. The social events giveback income to council. Employment creation has been a by-product also from these green spaces as the photographers can strategically position themselves at these places for customers.

Innovative and Collaborative Solution

How does the initiative show evidence of feasibility, including on-going financial and logistical support?

The water reclamation projects are funded through the revenue and capital budget of the municipality as well as other income streams such as the sale of sludge and reclaimed water to users. Annual budget allocations from the City of Bulawayo for each of the treatment works is done separated into votes.

Every year the Service Level Document contains the volumes of wastewater produced as a supporting evidence document. The water reclamation projects are funded through the billing system of the municipality as well as other income streams such as the sale of sludge and reclaimed water to consumers. Annual budget allocations from the City of Bulawayo for each of the treatment works is done separated into votes.

In what ways is the initiative innovative?

The funding of this are generated by the residents of the city in areas where sewer reticulation systems are installed. To achieve sustainability these costs are subsidised by income from then resale of sludge for use as fertilizers by farmers.

In the City of Bulawayo 3 methods are used to treat wastewater from namely,

a) The activated sludge process is a suspended film process that makes use of suspended mixture of micro-organisms to oxidize the biodegradable organics in the sewage.  The treatment of sewage by the activated sludge process is based more on the concentration of viable micro-organisms than on the organic loading of the sewage by aeration of the mixed liquor to promote bacterial growth and promote aerobic breakdown of BOD and this method is used at Southern Areas Sewage Treatment (SAST) and Aisleby 3 treatment works.

b) Biological filters are an example of a fixed media processes whose efficiency of sewage treatment is based on the concentration of the organics to be oxidized. Also like the Activated Sludge system, biological filters use micro-organisms to effect treatment ending with chlorination of the final effluent. This method are used at Luveve, Waterford, Thorngrove and Aisleby 1& 2 treatment works.

How is the initiative supported by collaborative working across disciplines and sectors?

The City Council Landscape team which is full time on ground utilities the reclaimed water for beautifying the city. Strategically planting trees along the roads, maintaining the football pitches who hold local and international games.

The gumtree plantation has been successful because of the water from Magwegwe wastewater treatment plant.

One of the green initiatives undertaken by the City of Bulawayo is supporting urban agriculture activities at Council owned lands such as at SAST in the Khami area where the reclaimed wate is used to grow crops and vegetables. Another benefit from the reclamation exercise is the sludge that is the solids from the wastewater that are removed throughout the treatment process. They are further treated to remove any bacteria, fungi or viruses that may have adverse effects on the environment for use as biofertilizers by farmers. The sludge is sold out in truck loads to farmers at reasonable rates to local farmers. This promotes the use of biofertilizers that have no negative impact on the groundwater as compared to synthetic fertilizers.

How does the initiative demonstrate evidence of community support?          

Land allocations for agricultural use is done by the city council to encourage the use of the reclaimed water to benefit the communities in the areas where these plants are located. For example, the Gumtree plantation. Urban agriculture can also be used to provide therapeutic treatment, enhanced environmental health, environmental restoration, and city greening. Urban agriculture’s beneficiaries benefit from better living conditions and increase environmental awareness.

Implementation, Impact and Replicability

How has the initiative had a ripple effect beyond the scope of the initiative itself, thereby demonstrating a change in the city’s and/or its partners’ way of working with plants?

The success of this initiative can be seen around the city of Bulawayo tower block gardens and Centenary Park amongst many that are evergreen, giving the landscaping a wonderful aesthetic view.

As an achievement reclaiming the water has ensured the availability of basic agricultural produce throughout the year by providing the water and biofertilizers to farmers. This is evident as fresh produce reaches the city every morning daily to ensure a healthier and sustainable living.

Reduced use of synthetic fertilizers has since been evident for vegetable farmers as the use sludge which is a more environmentally friendly option.

How has the initiative had a ripple effect beyond the scope of the initiative itself, thereby demonstrating a change in the city’s and/or its partners’ way of working with plants?

The initiative brought about numerous unforeseen benefits and innovations such as the addition of sludge digesters that produce biofertilizers.

The use of fertilizers has brought about an increase in agricultural practices such as urban agriculture which the city has embraced. The city promotes the practice of urban agriculture and has since passed an urban agriculture policy having observed that productivity is generally high.
Urban Agriculture has been practiced as a coping strategy to meet their immediate food requirements. This has been very beneficial to communities seeing a productivity level of 40kg per month per plot holder on crops such as choumoellier.

Urban agriculture is seen as a vehicle for empowerment, self-sufficiency, as a source of income, and as a means of ensuring the long-term use and management of natural resources. In both developing and developed countries, urban agriculture contributes significantly to household food security by ensuring the availability, accessibility, and affordability of unprocessed and processed foods.

How have other cities expressed interest in the initiative, or what potential does it have to interest other cities and be customised to their own circumstances?

The vision for urban agriculture has been realised for a long time in Bulawayo and other cities that have been practicing urban agriculture albeit in an informal manner due to perceived prohibitive urban policies and legislations. This vision has prompted the establishment of a city council interdepartmental committee in Bulawayo and other cities to examine the possibility of formalising urban agriculture in the city; review the existing urban agriculture policy and formulate proposals and policy guidelines for its development.

Urban agriculture is not a new invention. Urban agriculture activities, mainly vegetable gardens, growing of staple foods and poultry projects are found throughout the developed and developing countries. Various studies on urban agriculture in countries such as Ghana, Kenya, South Africa, Tanzania and Zambia have shown that in urban households of different social class, cultivated food in their backyards, front yards or in the urban periphery.

Sustainability and Resilience

What efforts have been made to reduce the carbon footprint of the initiative?

There are many ways to reduce one way to reduce your emissions and also make your property and community more beautiful, improve water quality, and provide numerous economic and social benefits… planting greens. Urban agriculture reduces the carbon footprint by removing carbon dioxide from the atmosphere and processing it into complex carbohydrates.

How have the anticipated impacts of climate change been considered?

Because the city is located in a drought area. Water should be conserved at all times. To maintain the greening of the city hence the city has taken advantage of water recycling to maintain the greening of the city. Also the City mantains the National tree planting day so as to increase the greening of the city. The city also has set by-laws, one of the laws states that no one is allowed to countdown trees in the city.

What processes does the initiative include for it to be considerate in its use of soils and other natural resources?

Close monitoring of the quality discharged from the wastewater treatment works is done by the City lab team.

Monitoring, Maintenance, and Management

How has the initiative been designed and implemented so that long-term needs for management and maintenance are reduced and can be met?

A maintenance team of plumbers is in place who maintain the reticulation system. The places are reserved specifically for greening the city and are not redesigned for other purposes.

The City of Bulawayo in its Policy for Urban Agriculture included the following objectives:
Objective 6.6.1A

To ensure financial resources are mobilized and made available to all urban farmers during the programme period.
Policy 6.6.1/A1

All urban farmers shall be encouraged in the first instance to mobilize their own financial resources to invest in urban agriculture. This may come from individual savings and other resources for urban agriculture.
Policy 6.6.1/A2

Financial institutions shall be encouraged to offer assistance to urban farmers in the same manner as they do to rural farmers.
Policy 6.6.1/A3

City Council shall prepare annual budgets for funding urban agriculture and source additional funding from partners, donors and government, as well as financial institutions to augment its own resources.
Policy 6.6.1/A4

All funds from external sources to be pooled together in one account specifically for Urban Agriculture and the account to be managed by City of Bulawayo.

What protocols are in place to facilitate monitoring of results?

To ensure that the effluent from the treatment plants complies the in-place standards, fully equipped Lab and qualified personnel based in Throngrove treatment works take samples from the respective reclamation plants on weekly bases and produce reports. This exercise also helps to monitor the quality of the effluent before discharging the treated wastewater to the environment and also monitor plants performance as a whole and play a very pivotal role in the success of the green city initiative. The Environmental Management Agency also work with the City Council for monitoring of effluent quality from the treatment works.

How has the initiative been enhanced in response to monitoring of results?

Environmental applications of water reuse in the city include river recharging e.g umguza river for the express purpose of improving conditions for aquatic life.  For areas such as Umguza farm and gumtree plantation water reuse for ecological enhancement is a beneficial option because reclaimed water is used to augment streamflows.

Due to the increase in the number of residents in the city, the Southern Areas Sewerage Treatment (SAST) is currently undergoing renovation to increase its capacity and efficiency.
Over the years we’ve seen the implementation of newer technologies moving from the Biofilter systems to more efficient Biological Nutrient Removal systems (BNR) in an effort to deal with large inflows a without compromising the quality of effluent. Thorngrove treatment works is planned for rehabilitation to effectively treat the wastewater as some industries around the area have been issued penalties after being discovered to deposit untreated industrial wastewater into the treatment work therefore it is on plane to rehabilitate and modify the treatment plant to accommodate industrial waste treatment.