24
ENVIRONMENT AND ENERGY
Municipal and urban wastewater ( Part 1 )
In this edition , Plumbing Africa discusses the sources and impacts of municipal and urban wastewater , highlighting the prospects for wastewater production and looking at the opportunities for water reuse and recycling .
Extracted from United Nations World Development Report
Figure 1 : Percentage of population served by different types of sanitation systems .
Municipal wastewater originates from domestic , industrial , commercial and institutional sources within a given human settlement or community . Urban wastewater includes both municipal wastewater and urban runoff . Since municipal and urban wastewater production is heavily dependent on the form and function of urban systems , the current and future patterns of urbanization must be critically examined in order to develop more sustainable approaches to wastewater management in the coming decades .
Figure 1 shows a breakdown of sanitation coverage by region , and hence of formal wastewater collection . It is clearly evident that sewers for wastewater collection are the favoured choice for much of the developed world , in spite of the use of on-site services in many rural areas and in areas undergoing unplanned urbanisation .
URBANISATION AND ITS IMPACT ON WASTEWATER PRODUCTION Urban areas around the world are facing enormous challenges . The acceleration of urban growth , changes in family and work practices , and the expansion of informal settlements will increasingly challenge the provision of services .
This is compounded by the impact of extreme events , climate change and migration in areas in conflict . Changing patterns of urbanisation have resulted in more inequity , with the poor in some developed regions facing the same challenges as those from developing regions .
By 2030 , global demand for energy and water is expected to grow by 40 % and 50 %, respectively ( UN- Habitat , 2016 ). Most of this growth will be in cities , which will require new approaches to wastewater management .
At the same time , wastewater management may also provide some of the answers to other challenges , including food production and industrial development .
URBAN FORMS The definition of rural and urban is most commonly based on national technical definitions related to geographical boundary considerations rather than population density or other defining characteristics .
However , in order to understand municipal wastewater production , it is necessary to consider a further analysis of ‘ urban ’, as differing urban forms do not only produce wastewater in different ways , but also guide the potential choices for the collection , treatment and use of wastewater ( see Table 1 ).
September 2018 Volume 24 I Number 7 www . plumbingafrica . co . za