14 ENVIRONMENT and ENERGY
An executive summary: the untapped resource
By Extracted from the United Nations World Water Development Report 2017
Most human activities that use water produce wastewater. As the overall demand for water grows, the quantity of wastewater produced and its overall pollution load are continuously increasing worldwide.
Untreated wastewater released back into the system has a major negative impact on the environment and contaminates clean water sources.
In all but the most highly developed countries, the vast majority of wastewater is released directly to the environment without adequate treatment, with detrimental impacts on human health, economic productivity, the quality of ambient freshwater resources, and ecosystems.
Although wastewater is a critical component of the water management cycle, water, after it has been used, is all too often seen as a burden to be disposed of or a nuisance to be ignored. The results of this neglect are now obvious. The immediate impacts, including the degradation of aquatic ecosystems and waterborne illness from contaminated freshwater supplies, have far-reaching implications on the well-being of communities and peoples’ livelihoods.
Continued failure to address wastewater as a major social and environmental problem would compromise other efforts towards achieving the 2030 Agenda for Sustainable Development. In the face of ever-growing demand, wastewater is gaining momentum as a reliable alternative source of water, shifting the paradigm of wastewater management from‘ treatment and disposal’ to‘ reuse, recycle and resource recovery’. In this sense, wastewater is no longer seen as a problem in need of a solution; rather, it is part of the solution to challenges that societies are facing today. Wastewater can also be a cost-efficient and sustainable source of energy, nutrients, organic matter, and other useful by-products. The potential benefits of extracting such resources from wastewater go well beyond human and environmental health, with implications on food and energy security as well as climate change mitigation. In the context of a circular economy, whereby economic development is balanced with the protection of natural resources and environmental sustainability, wastewater represents a widely available and valuable resource. The outlook is undeniably optimistic, provided action is taken now.
The world’ s water: availability and quality Globally, water demand is predicted to increase significantly over the coming decades. In addition to the agricultural sector, which is responsible for 70 % of water abstractions worldwide, large increases in water demand are predicted for industry and energy production. Accelerated urbanization and the expansion of municipal water supply and sanitation systems also contribute to the rising demand.
Climate change scenarios project an exacerbation of the spatial and temporal variations of water cycle dynamics, such that discrepancies between water supply and demand are becoming increasingly aggravated. The frequency and severity of floods and droughts will likely change in many river basins worldwide. Droughts can have very significant socio-economic and environmental consequences.
Highly vulnerable areas, where non-renewable resources( that is, fossil groundwater) continue to decrease, have become highly dependent on transfers from areas with abundant water and are actively seeking affordable alternative sources. The availability of water resources is also intrinsically linked to water quality, as the pollution of water sources may prohibit different type of uses.
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Increased discharges of untreated sewage, combined with agricultural runoff and inadequately treated wastewater from industry, have resulted in the degradation of water quality around the world. If current trends persist, water quality will continue to degrade over the coming decades, particularly in resource-poor countries in dry areas,
September 2017 Volume 23 I Number 7 www. plumbingafrica. co. za