Wastewater Treatment: A Growing Crisis and Its Solutions, Part One

Editors Note: In this post, Susan Davis, Founder of Improve International and Contributing Editor at Engineering for Change, discusses the growing crisis of wastewater treatment.

Lavender Hill Accra by Emory CGSW team

Fecal Plume from Lavender Hill. Photo Credit: The Emory CGSW team

There is a place called Lavender Hill in Accra, Ghana, where trucks dump 250,000 gallons of untreated sewage onto a beach and into the ocean every day. I was recently in Ghana to attend the annual conference of Loughborough University’s Water, Engineering and Development Centre (WEDC), where I heard other examples of the destinations and consequences of untreated wastewater.

The trucks pump fecal sludge from latrines in Accra’s neighborhoods without sewer lines and dump it, creating the brown plume shown in the photo. There is a wastewater treatment plant, but it is closed. The plant was financed by the United Kingdom and designed by a Dutch engineering firm, and it was functional for less than four years. It failed due to inadequate training of local operators and because it was designed for more dilute wastewater.

In another example, Bukom, a neighborhood in Accra, has a sewer line that goes straight to the ocean. Untreated wastewater from communities, laboratories, hospitals, and even morgues is used to irrigate vegetable gardens in Accra, as well.  This is similar to many other cities in developing countries. The water, sanitation, and hygiene (WASH) sector has not paid much attention to wastewater in the past, perhaps because the Millennium Development Goals focused on increasing access to improved toilet facilities.

“Far less attention has been paid towards ensuring that waste streams are adequately collected and treated prior to discharge into the environment,” Catarina de Albuquerque, former Special Rapporteur on the human right to safe drinking water and sanitation, wrote in framing paper for the Office of the UN High Commissioner for Human Rights.

Wastewater is defined as “a combination of one or more of:

  • domestic effluent consisting of blackwater (excreta, urine and faecal sludge) and greywater (kitchen and bathing wastewater);
  • water from commercial establishments and institutions, including hospitals;
  • industrial effluent, stormwater and other urban run-off;
  • agricultural, horticultural and aquaculture effluent, either dissolved or as suspended matter.

Untreated wastewater can spread disease to humans and damage key ecosystems such as coral reefs and fisheries. Yet, 80% to 90% of wastewater resulting from human activities is discharged into rivers or oceans untreated. This means that two million tons of sewage, industrial and agricultural waste is discharged into the world’s waterways each year. The combination of increasing wastewater production, increasing population, and rapid urbanization will lead to an ugly situation if we don’t rethink wastewater management.

Beyond treatment, we will also need to devise ways to reuse and recycle water. Wastewater is “simply too valuable to waste,” as Duncan Mara wrote in his book Domestic Wastewater Treatment in Developing Countries. The UN has predicted that by 2030, the world water supply will fall short by at least 40 percent, hitting areas like sub-Saharan Africa and Southeast Asia particularly hard. Reusing wastewater can help to ameliorate this challenge and, even better, it can be a source of nutrients for agricultural use.

The problem has caught global attention. Wastewater is now an integral part of the Sustainable Development Goals (SDGs). Two of the SDG 6 targets specifically mention wastewater:

  • By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally
  • By 2030, expand international cooperation and capacity-building support to developing countries in water- and sanitation-related activities and programmes, including water harvesting, desalination, water efficiency, wastewater treatment, recycling and reuse technologies

There are some promising solutions in place now that could be scaled up or replicated in other countries. In Part Two of this series we will look at examples of some of these promising solutions including decentralized wastewater treatment technologies that are being deployed in developing countries.