Sense or Nonsense ? Fossil Carbon energy wasted just to destroy more Carbon energy at "advanced" WWTP's?

Dear Colleagues,
In reference to "CIWEM Report - A Blueprint for Carbon Emissions Reduction in the UK Water Industry", I would like to start this topic, so practitioners and visioners may exchange views and "believes" about the future of ongoing water based WWTP's around the world, regardless "warm" or "cold" countries or political systems and -ism's involved.

For the time being "we" use much fossil carbon energy just to destroy very much more carbon energy at so called "advanced" WWPT's in "developed" countries, the "3 upper class-castles". This wasting might be fine if cheap fossil carbon energy would be endless available. But soldiers could and do make this fossil carbon energy just for a short time longer available for this 3 "upper class" castles EU, USA and China ( .... This is my general view on our energy wasting "system" around us.
But to simplify it, lets talk now only about technology, despite if all is seen only from the technology point of view, it will not be helpful...

To get more touchable on the topic, let me put up a technology hypothesis by using AD-systems:

An ABR e.g., is in my opinion just an improved UASB by purposely simplifications, as it is made from a number of UASB-tanks in series and do not need inoculate to start up, just anaerobic sludge is good enough. Even in 8-20 gradC it is OK for ABR under cold Europe condition. Larger HRT and voluminas are OK and planed, as a "cold" system like this produces energy instead of using it, with a by-effect 90% less FS (theoretical )!!! It will minimizing problems on agriculture contamination or costly incineration too. Under "cold" conditions much Methane will be in solution within effluent. So it needs Downstream Separations by simple cascades or cheap membranes, to make use of Methane and prevent GHG-emmisions. After AD and methane-gas separation simple aerobic treatment via simple bio-film plants (like engineered wetland or CW) and so on (or even a secondary costly ANAMOX-system, if no space is available).

This "low- to medium tech" is "good enough" for simple domestic sewage (mass-volumes), no need for high-tech AD +++ as it is used rightly within industrial-wwtp's for difficult industrial-sewage.

Make use of chemical energy content is the first step to recover nutrients like P & N too in an economical way. Because past nutrients recover developments been based only on additional energies from "outside".

For industrial and special sewage and e.g. for removal of trace organics in water/waste-water advanced techniques are highly necessary. This trace organics should not be used to argue for and to establish expensive "end of pipe" systems in domestic sewage-wwtp just for simple domestic mass sewage. It would be a very costly over-engineering "at this ends of pipes".

No need "to take a sledgehammer to crack a nut".

Over-engineered examples like DEUS 21 & CARISMO, in my opinion just swallowing R&D-money. This high-tech will not be a technology solution for existing domestic WWTP's, for the mass volumes on sewage:
- "DEUS 21" Frauenhofer Institut www.deus21.de and
- "CARISMO"(Carbon is money) Kompetenzzentrums Wasser Berlin www.kompetenz-wasser.de/CARISMO.519.0.html)
- and others, you name it please!

I would appreciate your inputs, views, "believes" and reply's on this topic.

All the Best
Detlef SCHWAGER MSc Tropical Water Engineering www.aqua-verde.de
Sanitation-Solutions without external energy
Low-Tech Solutions with High-Tech Effects
"Inspired by Circular Economy"
www.flickr.com/photos/aqua-verde/ http://forum.susana.org/forum/categories/39-any-other-topic-related-to-sanitation-or-to-susana/7438-sense-or-nonsense--fossil-carbon-energy-wasted-just-to-destroy-more-carbon-energy-at-qadvancedq-wwtps#7438

3 Answers

1. Hello Detlef, Congratulations with your comprehensive post on which I fully agree. The academic world focuses primarily on publications, on prestige and on acquiring R&D funds. The business world focuses primarily on selling products and silver bullet "solutions". In most cases sustainability, water & carbon footprints are just buzz words to get funding resp. sales. Being an M.Sc. professional engineer like yourself, after 37 years of practice, I still look at each new application with an open mind as to configure the most sustainable (resources) and economic (capex + opex) treatment and select the most appropriate process technology with efficient equipment and process controls. For most organic wastewaters this results in high-rate AD converting typically 90% of the organics to methane to save fossil fuel. The AD effluent is treated by low energy advanced activated sludge (AAS) as to biodegrade recalcitrant compounds and colloids enabling very clear and clean water for recycling. In most cases (realized worldwide over the last 35 years) several times more energy is produced/recovered than needed for the complete treatment including water recycling. This is what I would call sustainable.

2. Fully agree WWTP-AD + using nutrients of AD-effluent further to feet generated algae to the same or other AD. How fare is the actual implementation of made R&D results? Any examples to lean on? No commercials please!

3. While using solids digestion at treatment plants, my advocacy is to use secondary effluent to feed algae to purify the water instead of chemicals. This takes longer but the algae do a better job so make full recycling of the water economically feasible and importantly you gain a high volume supply of biodiesel. This allows the WWTP to become the biofuel producer for the water district and even with price gouging the price at the pump will be 1/2 of fossil diesel so very popular with citizens to remove the captive-market profiteers from the loop. Growing algae from wastewater effluent is done for 1/3 of USA biodiesel producers, but none of this is coordinated as a process tied to normal treatment plants as one would expect in a unified design of sewage processing. So, to add to the above recommendations, adding the wastewater processing takes the use of photo-bioreactors to be able to grow 24x7 to keep up with volume with climate control for any climate or time of year, harvesting has a number of options as does processing the oil for use in vehicles.