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A big challenge in modern wastewater treatment is the removal of micropollutants and multiresistant bacteria (MRB). Micropollutants, which includes such things as pesticides, pharmaceuticals, personal care products, food additives, and hormones, are dangerous for the environment and human health as we have previously reported. MRBs, and their antibiotic resistant genes (ARG), have been rated as a global health threat by the World Health Organization. Modern wastewater treatment plants are fairly effective at reducing the total number of MRBs, but it turns out they may also help select particular highly resistant strains that make it through the processing and they are only moderately successful at removing micropollutants. To address these new threats, many treatment facilities are discussing adding an additional treatment step. One of the more promising treatments being implemented is the use of ozone because it is economically feasible, and it significantly abates micropollutants.
What is largely unknown is the effect of ozonation on MRBs. Ozone is a strong oxidant and disinfectant and it is very effective on organic materials. A group of Swiss researchers investigated the extent that ozone kills MRBs and destroys ARGs when applied at the levels implemented by wastewater treatment plants. They performed laboratory experiments, and also took samples from a wastewater treatment plant. Their results are presented in a paper [Paywalled] in the journal Environmental Science & Technology. In the lab they found ozonation to be very effective at disrupting ARGs, but unfortunately it was not effective when applied to the secondary effluent at a treatment facility. What this means is that the new ozonation systems being implemented to deal with micropollutants, although they have much potential, will not be effective against antibiotic resistant bacteria.
Inactivation of Antibiotic Resistant Bacteria and Resistance Genes by Ozone: From Laboratory Experiments to Full-Scale Wastewater Treatment [DOI: 10.1021/acs.est.6b02640][DX]
(Score: 4, Informative) by VLM on Wednesday November 30 2016, @09:52PM
Why don't they use the gamma irradiation we should be using on our food to irradiate wastewater? Possibly at far higher doses than used for food.
The flow rate of sewage is really high. I looked into it when irradiated meat became available at my local store. The capital expense of a production line is like $5M for a small one vs $1M for steam heat sterilizer lines, and "they" figure amortized over a reasonable lifespan etc that sterilized meat might be as much at 10 cents per pound for high strength Co-60 that can kill anything that would give you food poisoning.
If a gallon of water weighs eight pounds and theoretically each person generates 150 gallons average of sewage per year (mostly clothes cleaning and flush water) and I have four people in my house and I pay a combined quarterly water and sewer bill and lots more handwaving then irradiating my poop would result in a roughly $40K sewer bill rather than the $75 or whatever it is exactly that I currently pay (obviously I'm not west of the Mississippi, we have more water than we know what to do with here, unlike CA). Saying $10K per month per house for the poop irradiation project (PIP) is probably correct to 1 sig fig.
The other problem is the city nearby me is notoriously incompetent and dumps raw sewage every time it rains etc. Not really the kind of people I'd want to trust with multiple ultra high strength Co-60 source. Nothing against CivEng in general I just live maybe 20 miles (upriver, thankfully) from a wastewater plant run by morons so giving those kids matches and telling the kids to go play just isn't happening as a practical matter. I'm sure most plants are better run.
(Score: 0) by Anonymous Coward on Wednesday November 30 2016, @10:52PM
> ... a wastewater plant run by morons
This may be fairly common. Here (eastern great lakes, prosperous suburb) there was a waste-to-fertilizer plant built about 20 years ago. The town was never able to get it working well enough to make a saleable product (or even a product they could give away and save landfill fees). Meanwhile, every year there was a new expensive consulting company hired to solve the problem(s), and a line on the town budget. A few years ago they finally gave up and cut their losses.