Water, climate and the environment. The fates of these three vital aspects of life on planet Earth are closely linked. Every extreme climate event (rising sea levels, storms, droughts, etc.) seriously disrupts resources such as water and sanitation services in the most vulnerable regions. At the same time, contaminated water is harming the environment and biodiversity everywhere. This report focuses on an issue that is rarely talked about: the environmental challenges of sanitation and the solutions for improving it.
Around the world, some 2.3 billion people still lack basic sanitation services such as toilets or latrines1. In Ethiopia, for example, only 6% of households have access to improved sanitation facilities, according to a report by the United Nations Children’s Fund (UNICEF)2. In total, tens of millions of people live near waterways that are full of sewage.
Underestimating the knock-on effect
Water contamination due to human, domestic and industrial activity, to demographic pressure or to poor management, has dramatic consequences – not least its effect on the human population. Every year, 2.4 million people die from water-related diseases, whether through a lack of drinking water, sanitation or hygiene. About 1.4 million of them are children under 14 who die from diarrhoea3.
But the situation has other damaging consequences. In many large cities, huge volumes of wastewater are discharged untreated into the environment. For irrigated crops, fish and fragile ecosystems, the consequences are dramatic. In France’s Indian Ocean archipelago of Mayotte, for example, the mangroves are a source of great biological wealth that is essential to the island and its lagoon. And yet, they are now seriously endangered by a lack of rainwater and the impact of urban drainage4.
One of the biggest challenges in wastewater management is its impact on the environment,” says Riccardo Zennaro, Programme Management Officer (Wastewater) at the United Nations Environment Programme (UNEP). “Water quality has a direct impact on both habitats and biodiversity. Once contaminants are in the environment, they flow from upstream to downstream, for example, with a series of knock-on effects on habitats, human health and biodiversity.”
Despite these very tangible impacts, the problem of sanitation and wastewater management has only a very low profile. “Wastewater is a silent polluter. People don’t think about what happens once the toilet is flushed,” says Riccardo Zennaro. “And because the subject is less eye-catching than others, one of the major challenges is public awareness.”
Despite some challenges, the issue does finally seem to be gaining people’s attention. An increasing number of companies, governments and stakeholders worldwide, such as the United Nations, research institutes and universities, are now launching initiatives. One fact cannot be ignored: improving wastewater management and sanitation has a wide range of benefits, well beyond the health aspects. ” If you invest in wastewater reuse, you will ultimately improve people’s access to water, which is a major benefit in areas of water scarcity. And by doing so, you will also empower the community.”
Solutions tailored to local needs and climate challenges
To deliver solutions for improving sanitation that are both efficient and suited to the local situation involves facing several challenges at the same time. Alternative, low-cost technologies that use natural solutions for wastewater treatment need to be identified. Another aspect that cannot be overlooked is their ability to cope with climate change effects (bad weather, flooding, drought, etc.) in regions that are particularly vulnerable.
“When conventional systems are not possible or in place, it is key to turn to low-cost, decentralised options, based on alternative approaches such as EcoSan (Ecological Sanitation),” explains Riccardo Zennaro. The advantage of these latrines is their ability to keep grey water and human waste separate, with urine and faeces being processed in dry toilets. Small scale treatment systems not only provides people with access to basic sanitation and reduces environmental contamination, but also transforms wastewater and sewage into reusable by-products for agriculture and energy. In addition to their low cost, a major advantage is that these systems require very little maintenance.
Meanwhile, an initiative in Delhi, India aims to tackle the sewage runoff that is seriously polluting the city’s waterways. In December 2021, the Indian government announced its intention to treat over 95% of the city’s wastewater by the end of 2022. For its part, the United Nations Environment Programme (UNEP) launched a study to assess the different technologies being used by Delhi’s treatment plants for nutrient recovery and recycling, as the government looks to support the safe and sustainable reuse of wastewater5.
The study found that the Moving Bed Biofilm Reactor (MBBR) system is the most suitable for the city’s specific needs. Invented in Norway, the MBBR is a modern system that uses a combination of biological rather than just chemical or mechanical processes to treat water and remove pollutants. The main drawback is its high maintenance costs.
These advances can be a source of hope in the many regions around the world that suffer the effects of poor or non-existent sanitation. For there is no shortage of technological innovation when it comes to wastewater treatment plants.
One example is the East Bay Municipal Utility District (EBMUD) in Oakland, California. For the past 10 years, the site has been using organic waste from local food processors, food producers and livestock farmers to make better use of the excess capacity of its existing anaerobic digesters.
Similarly, through biogas production and recovery, as well as the use of solar panels, the wastewater treatment plant in Gresham, Oregon is the first in the Pacific Northwest region to produce more electricity than it consumes. Similarly, DC Water is the first plant in North America to use the thermal hydrolysis process developed by a Norwegian company, Cambi. The biogas created by the process is used to generate 10 megawatts of electricity, meeting one-third of the plant’s energy needs.
To help priority regions move towards these types of innovative solutions, a series of information resources have been made available. Since 2008, for example, the Swiss Federal Institute of Aquatic Science and Technology (EAWAG) has published the Compendium6, a guide to tried and tested technologies for engineers and planners in low and middle-income countries. UNEP, together with the International Water Association (IWA), has developed a wastewater technology matrix, a tool that helps in the planning for the best treatment technology to use based on local parameters.
Aside from information, the main issue remains a financial one, according to Riccardo Zennaro. “Wastewater management is a sector that needs more resources and funding to overcome the challenges, to modernise existing wastewater treatment systems and to install new ones. To summarize, the cost of action in the field of wastewater management and sanitation provision is lower than the cost of inaction”.