As demand for fresh water intensifies, wastewater is frequently being seen as a valuable resource. Furthermore, wise reuse of wastewater alleviates concerns attendant with its discharge to the environment. Globally, around 20 million ha of land are irrigated with wastewater, and this is likely to increase markedly during the next few decades as water stress intensifies. In 1995, around 2.3 billion people lived in water-stressed river basins and this could increase to 3.5 billion by 2025. We review the current status of wastewater irrigation by providing an overview of the extent of the practice throughout the world and through synthesizing the current understanding of factors influencing sustainable wastewater irrigation. A theme that emerges is that wastewater irrigation is not only more common in water-stressed regions such as the Near East, but the rationale for the practice also tends to differ between the developing and developed worlds. In developing nations, the prime drivers are livelihood dependence and food security, whereas environmental agendas appear to hold greater sway in the developed world. The following were identified as areas requiring greater understanding for the long-term sustainability of wastewater irrigation: (i) accumulation of bioavailable forms of heavy metals in soils, (ii) environmental fate of organics in wastewater-irrigated soils, (iii) influence of reuse schemes on catchment hydrology, including transport of salt loads, (iv) risk models for helminth infections (pertinent to developing nations), (v) microbiological contamination risks for aquifers and surface waters, (vi) transfer efficiencies of chemical contaminants from soil to plants, (vii) health effects of chronic exposure to chemical contaminants, and (viii) strategies for engaging the public.

http://dro.deakin.edu.au/eserv/DU:30007424/stagnitti-wastewaterirrigation-2007.pdf

Wastewater irrigation: The state of play

Understanding the nexus between energy and water - water used for energy and energy used for water - has become increasing important in a changing world. As growing populations demand more energy supplies and water resources, research aims to analyze the interconnectedness of these two resources. Our study sought to quantify the energy-water relationship in Texas, specifically the relationship between electricity generation and water resources as it pertains to policy and society. We examined the water requirements for various types of electricity generating facilities, for typical systems both nationwide and in Texas. We also addressed the energy requirements of water supply and wastewater treatment systems, comparing national averages with Texas-specific values. Analysis of available data for Texas reveals that approximately 595,000 megaliters of water annually - enough water for over three million people for a year - are consumed by cooling the state's thermoelectric power plants while generating approximately 400 terawatt-hours of electricity. At the same time, each year Texas uses an estimated 2.1 to 2.7 terawatt- hours of electricity for water systems and 1.8 to 2.0 terawatt-hours for wastewater systems - enough electricity for about 100,000 people for a year. In preparing our analysis, it became clear that substantially more site-specific data are necessary for a full understanding of the nature of the energy-water nexus and the sustainability of economic growth in Texas. We recommend that Texas increase efforts to collect accurate data on the withdrawal and consumption of cooling and process water at power plants, as well as data on electricity consumption for public water supply and wastewater treatment plants and distribution systems. The overarching conclusion of our work is that increased efficiency advances the sustainable use of both energy and water. Improving water efficiency will reduce power demand, and improving energy efficiency will reduce water demand. Greater efficiency in usage of either energy or water will help stretch our finite supplies of both, as well as reduce costs to water and power consumers.

/pdf/the-energy-water-nexus-in-texas-1myrfxbdwk.pdf

The energy-water nexus in Texas

In recent times, the coalescence of different pressure has put a major strain on water supply globally. The level of water abstraction is reaching its natural limits, and this calls for a dramatic shift in water utilization concepts. This publication addresses the economic and financial issues and the methodology and procedures involved in the analysis of water recycling projects as part of a comprehensive water planning process. The issue is dealt within the wider context of water resources and covers human health, water quality, acceptability, institutional constraints, and other factors, all of which have economic implications and affect the feasibility of reuse schemes. The recycling of urban wastewater is a key link in Integrated Water Resource Management that can fulfill several different, but interrelated objectives. These are expressed as win-win propositions, delivering simultaneous benefits to farmers, cities and natural environmental systems, part of solutions to the urgent global problems of food, clean water, the safe disposal of waters and the protection of the vital aquatic ecosystems.

The wealth of waste: the economics of wastewater use in agriculture.

Coastal wetlands perform a unique set of physical, chemical, and biological functions, which provide billions of dollars of ecosystem services annually. These wetlands also face myriad environmenta...

https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ehs2.1258

Restore or retreat? Saltwater intrusion and water management in coastal wetlands

One of the key elements in the transformation towards a circular economy (CE) is providing more sustainable practices for resources and waste management. Improvement actions focused on transformation towards a CE should be targeted at all groups of materials and waste. As water is essential for human survival and well-being and plays a significant role in sustainable development (SD), the actions related to the reuse of water and the recovery of raw materials from wastewater and other water-based waste should be taken. The paper presents a proposition for a new CE model framework in the water and wastewater sector, which includes the six following actions: reduction—prevent wastewater generation in the first place by the reduction of water usage and pollution reduction at source; reclamation (removal)—an application of effective technologies for the removal of pollutants from water and wastewater; reuse—reuse of wastewater as an alternative source of water supply (non-potable usage), recycling—recovery of water from wastewater for potable usage; recovery—recovery of resources such as nutrients and energy from water-based waste, and rethink—rethinking how to use resources to create a sustainable economy, which is `free` of waste and emissions. The novelty of the proposed CE model framework is that it presents possible ways of implementing CE principles in the water and wastewater sector, with a strong emphasis not only technological but also organisational and societal changes. Application of the proposed model may help to further transform the European economy to the CE model. Moreover, the indicated model can be significant tool supporting an assessment of local or regional progress towards CE in the water and wastewater sector and further environmental management and planning.

/pdf/circular-economy-model-framework-in-the-european-water-and-3iv6252xl4.pdf

Circular economy model framework in the European water and wastewater sector

The world's supply of fresh water is finite and is threatened by pollution. Rising demands for water to supply agriculture, industry and cities are leading to competition over the allocation of limited fresh water resources. This paper examines how water reuse increases the available supply of water and enables human needs to be met with less fresh water. The paper is illustrated with water reuse case studies in agriculture, urban areas, industry and water resource supplementation in Australia and other countries. The links between water reuse and sustainable water management are examined. Water conservation and water reuse produce substantial environmental benefits, arising from reductions in water diversions, and reductions in the impacts of wastewater discharges on environmental water quality. Some examples are presented demonstrating the environmental benefits in quantitative terms. The paper also describes the economic and environmental benefits identified in a number of recent integrated water cycle planning studies in Australia.

J. Anderson

Papers

The environmental benefits of water recycling and reuse

The environmental benefits of water recycling and reuse