Reuse of Wastewater (interview with Dr. Valentina Lazarova)

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Reuse of Wastewater (interview with Dr. Valentina Lazarova)

Reuse of Wastewater


Reuse of treated municipal wastewater is normally taken as an intervention that supplements water supply. That is rightly so, since in most cases in developing countries, the treated municipal wastewater is used for irrigation of road greenbelts, golf courses, parks and playgrounds.

I recently came across an interview of Dr. Valentina Lazarova, an expert with over 25 years of research and practical experience in the field of Environmental Engineering. She is the chair of the IWA (International Water Association) Water Reuse Specialist Group. The interview was conducted by Dr. Vidhya Chittoor Viswanathan, Impact Director at AquaSPE, Zurich, Switzerland. Dr. Vidhya has a strong technical background in civil and environmental engineering. Her doctoral thesis was on studying the impact of river restoration on surface water quality across various scales (from river reach-scale to catchment-scale).

On the constraints in the reuse of wastewater, Dr Valentina said:

“The main constraints for the development of potable water reuse are inadequate communication, misunderstanding of the efficiency and reliability of the available treatment technologies and water quality control tools. As a consequence, public opposition and concerns of unknown micropollutants or pathogens were the key arguments against the development of some potable reuse projects. In fact, unplanned potable reuse is a wide uncontrolled practice worldwide associated with higher health risks compared to planned water reuse. For these reasons, the major challenges for indirect potable reuse remain the public support, regulatory approval, high capital and operation costs, including very high monitoring costs for emerging micropollutants.”

Dr. Valentina’s response is useful as the efficiency of treatment technologies and, monitoring of treated effluents are the two important adjuncts that has to be considered seriously, if risks, associated with the use of treated wastewater, are to be avoided.

As regards the fears of presence of pathogens, Dr Valentina says:

“We have also many examples where misunderstanding of water reuse is blocking the development of projects for irrigation with well treated wastewater, while many rivers used for irrigation are much more polluted that recycled water. Independent of the type of reuse application and the country, the public’s knowledge and understanding of the safety and suitability of recycled water is a key factor for the success of any water reuse programme. Consistent communication and easy to understand messages need to be developed for the public and politicians explaining the benefits of water reuse for the long term water security and sustainable urban water cycle management.

There are few proven solutions available to convince the public at large and the project stakeholders regarding the safety and relevance of water reuse. Undoubtedly, the use of a clear and positive terminology and simple explanations on water quality, treatment technology and water reuse benefits are necessary to build-up credibility and trust in water reuse. Existing experience and lessons learned are very important to convince decision makers. Finally, the most important recommendation is to inform and involve the public, politicians and all stakeholders from the beginning of any water reuse project. The increasing media impact and the new communication tools via internet should also be taken into account.”


While many rivers are polluted and receive untreated wastewater discharges, Dr. Valentina’s point of knowledge and understanding of the safety and suitability of the recycled water merits attention.

On treatment technology, she says: “The combination of microfiltration (MF) and reverse osmosis (RO - recognised as a “multiple barriers” polishing of municipal effluents - is considered as the best available technology for potable water reuse applications.”

For large scale operations, e.g., NeWater Project in Singapore, her point of view is correct, but in case of small-level situations in developing countries, it would be rather difficult to go for MF and RO technologies, if the treated wastewater is to be used for irrigation.

The details of the interview can be accessed at:

thewaternetwork.com/post-FfV/interview-o...kC1VqBD5JJZNm5o2Q9yg

While still on the same note, I came across a by article by Gary Chandler titled: Alzheimer’s Disease Epidemic Fueled By Sewage Contamination. The article sent shivers through my spine. I have created a separate post on it here:
forum.susana.org/forum/categories/26-hea...eimers-disease#15323



F H Mughal

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Re: Reuse of Wastewater

Dear Eng. Mughal

Kindly note that we reprinted a related paper entitled “Investing in the Reuse of Treated Wastewater” in the May-June 2014 edition of the Africa Water, Sanitation & Hygiene”.

The paper was prepared by Chris Scott of International Water Management Institute (IWMI). It was revised by Salah Darghouth, Water Adviser for the Agriculture and Rural Development Department (ARD) of the World Bank, and Ariel Dinar, Lead Economist in ARD at the World Bank—both part of the Water for Food Team.

The paper was reprinted with permission and the pdf version is enclosed in the attachment.

Kind regards,

Mwaniki

Am the publisher of the Africa Water,Sanitation & Hygiene and the C.E.O. of Transworld Publishers Ltd.,Nairobi-Kenya.

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Re: Reuse of Wastewater

Dear Eng. Mwaniki,

Thank you for posting an interesting paper. One of the recommendations in your paper is:

Awareness building on health and environmental risks for farmers using untreated wastewater or reclaimed water

A good paper indeed! Thank you,

Kind regards,

F H Mughal

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Re: Reuse of Wastewater

Hi Eng. Mughal

Please address me simply as Mwaniki. Am not a qualified engineer and wish I were one. Kindly note I inadvertently omitted an article in the current edition of the Africa Water, Sanitation & Hygiene Sept-Oct 2015 Vol.10 # 5.

This article is entitled ‘Egyptian Experimental Farm Reveals Possible Market for 'Sewage Farming' Agricultural Products’ and findings in the experiment in this Egyptian farm, say the treated wastewater is safe.

Kindly go to our journal in the system and perusal the article.

Best regards / Mwaniki

Am the publisher of the Africa Water,Sanitation & Hygiene and the C.E.O. of Transworld Publishers Ltd.,Nairobi-Kenya.
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Re: Reuse of Wastewater

Dear Mwaniki,

Thank you for your post. I note that in the Egyptian experimental article, treated wastewater is considered safe for use.

Regards,

F H Mughal

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Re: Reuse of Wastewater

Hi Eng. Mughal

As you may be aware due water scarcity researchers are looking into ways whereby wastewater will be drinkable in future.

Several solutions that wastewater and water utilities are turning to is Ozone. They say, Ozone also offers a solution for utilities looking to move away from chlorine and reduce disinfection byproducts (DBPs).

They say ultraviolet disinfection technology may not offer drinking water quality but it may be clean enough for reuse in agriculture.

And of course there is nanotechnology has long been important in providing clean drinking water and irrigation for food crops.

Kind regards / Mwaniki

Am the publisher of the Africa Water,Sanitation & Hygiene and the C.E.O. of Transworld Publishers Ltd.,Nairobi-Kenya.
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Re: Reuse of Wastewater

Dear Wastewater Reuse Students,

The logical reuse of greywater, not blackwater, is more than possible right now with the use of a whole bunch of ozone.

We initially used UV but found ozone to be much more useful in many different aspects.

Creating ozone with the addition of an oxygen generator, venturi, sealed container and an ozone dis-struct (converts back to 02) has worked very well for us in not only disinfection but also in breaking up any remaining organics after 1 micron filtration.

From ozone to RO with a monitoring and recycle of the concentrate up to extremely high levels until discharging a modest 10% instead of the standard 50% to the composter.

The secret is having a good greywater treatment system capable of not only treating but also dealing with the hydrocarbons, which we do in the composter as well.

Clint
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Re: Reuse of Wastewater

Hi Clint,

I don’t think I contradicted myself in the treatment of wastewater with ozone for reuse.

In fact some companies use ozone-enhanced biologically active filtration system and multi-barrier solution combines ozone, filtration and analytical instrumentation to deliver optimal wastewater treatment for water reuse.

As for greywater treatment it’s recommended to use ultrafiltration for the reduction of turbidity.

Kindly comment on this.


Regards / Mwaniki

Am the publisher of the Africa Water,Sanitation & Hygiene and the C.E.O. of Transworld Publishers Ltd.,Nairobi-Kenya.
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Re: [SuSanA forum] Reuse of Wastewater (Greywater, blackwater or wastewater reuse, irrigation, aquaculture)

Dear Mwaniki,

Very nice to communicate with you.

I would be interested to learn more about the companies and products you speak of combining various interesting concepts.

Again, my experience is totally with greywater, no blackwater recycling and/or reuse.

I do not believe we should have any blackwater in the first place by utilizing separation and composting/vermiculture toilet and organic kitchen resource technologies first and then following that logical premise to the real potential of just cleaning up greywater.

We initially used ultrafilters before the RO's but determined that we did not need them because we are recycling Greywater RO water as our source instead of fighting all of the issues with new incoming water with all of the different issue potentials. The ultrafilters were thought to protect the RO but by utilizing the ozone we eliminated those expensive filters and removed the ozone prior to the RO to protect those membranes.

Our ozone lesson had to do with utilizing all stainless, not plastic, components and fittings. Containment is a big issue with ozone.

But ozone, when utilized safely, is the best.

Also, Regards,

Clint
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