All-or-nothing in water treatment?

This page in:

During the World Bank's Water Week last month, one topic discussed was "Balancing Brown and Green Interests." Not everyone knew that the "brown interest" is sanitation, including wastewater treatment, and that the "green interest" is environmental sustainability. However, my real surprise was to discover the conflicting interests.

Wastewater infrastructure is a big business everywhere -- the U.S. Environmental Protection Agency estimates that the U.S. alone needs to invest roughly $140 billion over the next 20 years in wastewater treatment systems to meet water quality standards. And, while treatment of wastewater effluent seems a no-brainer...

the opportunity costs of building treatment facilities in developing countries vis-à-vis investing in other poverty alleviation interventions is substantial.

So the buzz on the smart route to wastewater management in developing countries is a "phased approach." Investment in basic or primary wastewater treatment may happen now, and stepped up secondary and tertiary treatment occurs later down the road.

Sounds like a good idea? Yes, but let's not forget that wastewater treatment must meet the local environmental standards for water quality. And that these standards are often based on western models, which most middle-income countries and cities still struggle to pay for.

So even if there is a high class wastewater treatment plant, and piped water supply and (even less likely) sewerage removal, there’s a good chance the plant might be sitting around unused due its high operations and maintenance costs.

The challenge is to reconcile environmental safeguards and environmentally sustainable agendas. While safeguards call for compliance with local environmental standards, sustainability depends on an economic valuation of the cost of untreated effluent water to in-stream (fisheries, tourism) and downstream uses (uptake by communities). Even valuing the environmental damage due to untreated wastewaters is a tricky business.

Lastly, sanitation engineers tend to plan big, coming up with long-term plans for water and sewerage connections that require a ‘big-ticket’ investment to install primary, secondary and tertiary treatment systems. But this all-or-nothing approach is expensive and often leaves municipalities with no treatment at all.

The Bank is still learning on this one. One lesson is that the toolbox for increasing access to sanitation includes not only piped sewerage to treatment plants, but also on-site sanitation, and low-tech, newer, interventions, like constructed treatment wetlands and water reuse. These lower-tech solutions are appearing again and again in the Middle East and North Africa as well as for South Asia. Again, another universal lesson is look to local solutions and support these. What do you think?


Tracy Hart

Senior Environmental Specialist

Join the Conversation

The content of this field is kept private and will not be shown publicly
Remaining characters: 1000