Water and Sewage Treatment: Expertise Unlimited

Sean Moran, our Principal Engineer writes this occasional blog about his experiences. Our company (Expertise Limited) design, commission and troubleshoot Sewage, Industrial Effluent and Water Treatment Plant. We provide Process and Hydraulic Design, Staff Training, Review and Audit and Expert Witness Services.

Tuesday, 19 January 2010

 

Business as usual II

The call-out didn't come at 3AM Sunday morning as predicted, but at noon the previous day. Frost damage had shattered many pipes, several pumps were air-locked, and there were unexpected foreign bodies in the feed which were causing blockages-and of course the buffer tanks were completely full at both sites, and the generators, instrumentation and SCADA system were also misbehaving.

It took half a day to patch things up, clear the blockages and airlocks, and get both plants running at top speed again to shift the melt-water.

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Thursday, 19 November 2009

 

Emergency Callout Groundwater Treatment

A call-out to a groundwater treatment plant earlier in the week showed a few interesting problems. "Dirty" power from a failing generator caused the failure of a single instrument (a Siemens Hydroranger), but the knock-on effect was total plant failure.

The software programmer had "interpreted" the requirements of the Functional Design Specification in such a way that this instrument became critical for plant operation. This was especially annoying as there was a backup instrument working on a more robust principle, but no way to switch plant operation over to this alternative instrument without a programmer on site.

Of course at the point where I was called, the working day was coming to an end, the plant's feed lagoon was on the point of overtopping, and it was raining. I love a challenge!

Naturally there was an expedient way to get the plant to go again, but the fix was a little questionable. I consequently thought it best to connect a web-cam into the system so that I could see and hear what was going on remotely, as well as being able to see what the SCADA shows. All is now well with the plant.

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Wednesday, 4 June 2008

 

Design Errors: Static Mixers

A quiet sort of a week in the main. Cyril continues his research into treatment of PCBs in groundwater. I have been engaged with the pharmaceutical client mentioned previously on here.

They have what must be one of the worst effluent treatment plants I have ever seen in terms of fundamental design flaws. One of the biggest of them was the use of static mixers to mix acid and coagulant with effluent, which was pumped by diaphragm pumps. This showed a fundamental misunderstanding of the nature of static mixers in the system designer. Static mixers blend fluids across the body of the mixer. If you feed them with a pulsating flow from a diaphragm pump, and an out-of synch. pulsating flow from a dosing pump, you end up with constantly varying degrees of mix in the outlet flow. The normal rule of sampling at least 10 pipe diameters downstream to get 95% degree of mix no longer applies. Your pH probe for example will see extreme variation in measures pH, and instead of gaining control to +/- 0.1pH units as you should from a system like this, you will be lucky to see +/- 0.5 pH units.

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Wednesday, 21 May 2008

 

PCBs and Pharmaceutical Effluent

It's been a quiet week in the office. I've mostly been attempting to teach my French work experience student (Cyril) how to use a library to research an area of scientific interest. In this case, the subject of interest is PCB contaminated groundwater. He is looking as some problems with floating oily sludges on a treatment plant I look after.

It turns out that the French-speaking world have never heard of the Science Citation Index and Chemical Abstracts. I'm waiting to find out what their librarians recommend as an alternative.

Just as I write that things are quiet, I have received a call from some people I quoted six months ago to look at a problem on a pharmaceutical effluent treatment plant...

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Wednesday, 14 May 2008

 

Water: Science and Pseudoscience

I've decided to start a blog on the company website, covering things which interest me professionally.

I'm a Chemical Engineer and Environmental Scientist, working mainly in the field of Water Engineering, though I do also deal in more general environmental advice, mostly on behalf of a government funded scheme called Envirowise.

I used to work for water contractors who you will not now have heard of, because it is seemingly a rule in the water industry that companies have to change the name of their company from time to time, for a number of reasons. For good companies, this is usually something to do with the marketing department. For bad companies, the reasons may be less honourable. None of the people I used to work for went bust by bidding jobs at less than cost and then came back one month later as "(old company name) 2008 Limited", but this is far from uncommon in the industry.

I do quite a bit of work of packaged sewage treatment plants which are misbehaving, look after some groundwater treatment plants, and am also presently involved in something I do a bit of from time to time, water feature design. I am helping with the design of water features in the Parc1 development in Korea. Don't click on the link unless you have broadband, the graphic designers have gone nuts on the website.

I'm also interested in water quackery, and will post some stuff on this as I come across new examples.

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