Water, Sanitation & Hygiene Editor shares his thoughts on the future of wastewater treatment

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Water, Sanitation & Hygiene Editor shares his thoughts on the future of wastewater treatment

After over 40 years in the field of wastewater treatment and publishing seven Open Access textbooks with IWA Publishing,  Journal of Water, Sanitation & Hygiene for Development  Editor Marcos von Sperling shares his thoughts on the future of wastewater treatment ahead of his retirement in September.

What is your perspective on biological wastewater treatment?

My first thinking in  terms of wastewater treatment is how essential it is in terms of pollution control and for protection of the environment and public health. My subsequent reaction is how much we still have to do, on a worldwide basis, to revert the poor statistics we have in terms of coverage, especially in low- and middle-income countries (LMIC).

Now, specifically on wastewater treatment using microorganisms, or biological wastewater treatment, which is what the question meant, my immediate thinking is how beautiful it is. It is amazing to be able to understand biological, chemical and physical phenomena that take place in nature, and adapt them to perform the task of removing pollutants in a controlled and optimized way, taking place in our wastewater treatment plants. The developments in this field are impressive, and we have different treatment alternatives and technologies to cater for most of our needs, whether they are in a developed or a developing region, in a cold or warm climate, if the treated effluent is to be discharged in a large river or in a sensitive water body, or, even better, if it is going to be used for productive purposes, and what pollutants we need to remove or recover. There are options to cover all these situations, and this is striking. And the scientific developments go from strength to strength, with amazing microbiological breakthroughs and an evolving in-depth mathematical representation of the mechanisms that take place in the treatment plants. This beauty is, for sure, one of the drivers that attract researchers to the field.

What challenges do you foresee in biological wastewater treatment?

I think that we have no technological constraints in biological wastewater treatment – there are treatment processes that can be adapted to virtually all needs and objectives. The main challenges are associated with the worldwide deficit in the coverage in several items of the sanitation chain, and how to revert this situation. This is especially the case in LMIC, which are also short in many other items associated with public health and general quality of life, such as education, health assistance, employment, personal safety and others. Priorities need to be set, but all of them are essential, and should not compete for government attention. Usually, the first image we have is that funds are not sufficient for implementing wastewater treatment. Yes, this might be true in most cases for the implementation of new treatment plants, but the water and sanitation service providers need to go beyond this first step, and also face the various challenges that come after the treatment plant has been commissioned. Plants need to operate well and achieve their objectives, and here we also see a huge challenge, associated with proper operation and maintenance, so that wastewater treatment remains sustainable on the long run. The causes for this are many, but they need to be well sorted out. In essence, most of the challenges are associated with management aspects, and not to technological ones.

What are new cost effective systems that can replace existing treatment systems?

Cost effectiveness is a broad concept, because it is intrinsically associated with the treatment objectives, and how much needs to be invested in order to achieve them. Even the concept of what is a sustainable treatment process is also difficult to characterize, because there are different angles to approach the concept of sustainability.

The wastewater treatment field keeps advancing with new process configurations. But if we cast our eyes to LMIC again, we see that we need simple solutions that can be operated and maintained during the planning horizon of the treatment plan. If I have to give just one example of a successful approach for LMIC (and indeed for other countries), I would refer to nature-based solutions, because of their conceptual simplicity, capacity of achieving different levels of pollutant removal, small or null energy consumption and usual low operating costs. These encompass systems such as waste stabilization ponds and constructed wetlands, with different configurations and operational modes.