New technology can solve wastewater crisis

Content image - Phnom Penh Post
Students row their boats as they leave a school at a floating village in Kampong Chhnang province. According to UNICEF, 12 per cent of schools in the East Asia and Pacific region have no drinking water facilities and 32 per cent have no sanitation facilities at all. AFP

World Toilet Day, today, might not sound like the most exciting of international commemorations. But, given that around 780 million Asians are forced to defecate in the open, and that approximately 80 per cent of wastewater across the region is returned to the environment untreated, the annual marker does highlight one of the more immediate and pressing concerns faced by the region, and the planet.

These raw numbers have very real implications. According to UNICEF, 12 per cent of schools in the East Asia and Pacific region have no drinking water facilities and 32 per cent have no sanitation facilities at all. Healthcare centres across the region are also drastically short of appropriate sanitation services.

These issues generate disastrous impacts at both the personal and the community level. Education is heavily impacted and girls in particular, especially those who are menstruating, tend to avoid school due to inadequate toilet facilities.

Public health also suffers as children in particular, with less immunity to disease than adults, are forced to bathe in and drink contaminated water, often the result of poorly managed, or non-existent, wastewater treatment. Thousands of children get ill and die every day from various fecal-oral diseases, including, potentially, Covid-19. Often fatal illnesses like these are easily avoided when clean sanitation solutions are available.

These figures also indicate that the problem is far from being solved.

Clearly, governments, the private sector and civil society organisations, despite some progress, are struggling to get ahead of the explosive economic and social growth in the region, and the wastewater dilemmas this causes.

Often, the solutions tend to head in the direction of centralised or reticulated sewage systems. But, such big-ticket options tend to marginalise two important groups in Asia where appropriate wastewater treatment is least accessible: a) regional communities outside urban areas and b) lower socio-economic communities within urban populations.

On-site systems, known as DEWATS or DWTs – Decentralised Wastewater Treatment Systems – have been increasingly used in areas without access to central sewage plants. Systems such as pit latrines, compost toilets and septic tanks have been widely used.

Many of these systems tend to focus on removing or containing the effluent rather than treating it so it can be safely dispersed back into the environment. They often require considerable energy to run properly and need servicing by trained operators. It many cases, they are not sustainable.

Where treatment systems do exist, they are often old-style aerated treatment technology, known as AWTS.

The basic problems with AWTS are as follows: they use chemicals which can be dangerous and are failure-prone if mis-used, they require electricity, they have a relatively high failure rate, they are not scalable, they are vulnerable to natural disasters and they also require maintenance by trained service-providers.

Such treatment problems can be addressed by existing technology, using more environmentally sustainable and cost-effective approaches. Different treatment systems, such as various forms of ‘passive’ wastewater treatment technology, can be applied usefully and effectively to existing wastewater problem areas, such as those noted above, treating wastewater to advanced secondary standard.

As we enter the third decade of this century, it is time to reconsider our approach to vital issues like wastewater treatment. Old technology may no longer be considered a viable, ongoing solution. Clearly, in broad terms, it isn’t working. The proof is written in the daily tragedy of lives lost to, and in the many communities held back by, poor sanitation and limited hygiene facilities.

Perhaps, on this day, and with Sustainable Development Goal #6 in our sights, we can embark on a new, flexible, cost-effective and sustainable water sanitation and hygiene journey for all across Asia which isn’t bound by old ideas but is invigorated by fresh thinking.

Ian Christesen is a consultant for a number of passive wastewater technologies in Australia and director of the National On-Site Providers Association (Australia). He has been an environmental adviser to the private sector and governments in Australia and internationally.