Saturday, 27 October 2012


I'm off to look at a number of problems with one of the plants I look after in Manchester today. The reported problems are that the sand washer on a continuous sand filter has stopped working, along with ancillary systems as the system has sucked up a load of high solids sludge which has contaminated several stages of tretament, and the monitor for the SCADA screen has chosen this as a good time to stop working. There will undoubtedly also be a few other little problems which will get in the way of the easy fix.

Put out my reports on papermill effluent treatment and another industrial effluent treatment job yesterday, which I am quite pleased with.

The paper-mill effluent treatment operators had amassed an enormous amount of monitoring data, which made it possible to be unusually sure as to what was going on, once I had handled the information overload with some statistics. 

The other industrial effluent treatment job involved use of a novel biotechnology product ( not something I do often, being quite conservative) to render an impossible to treat effluent readily treatable by means of a temporary plant constructed with hired equipment.

Interesting teaching experiences this week, getting first-year engineers to deal with the sketchy information and loosely defined problems which they will work with when they become professional engineers. I've also been arranging for the IChemE Safety and Loss Prevention Roadshow to visit us in November.

I'm going to complete my outline design of the SCWO plant as well this weekend, hopefully. Things should calm down a bit now that I have these jobs cleared, though many of them have the scope for follow-on work.

Saturday, 13 October 2012

Papermill Effluent - Capacity and Turndown

Went to look at a paper-mill effluent treatment plant yesterday, which had never met its design performance, mostly down to two things - insufficient capacity, and lack of controllability. Of course if you have enough capacity, controllability is far less of an issue.

When I was working at Water Engineering in Banbury, someone told me that they had evaluated the margin of safety which went into their standard design procedure for aeration systems by comparing actual with theoretical performance and that it was on some measures as high as six. Some things were six times as large as they theoretically needed to be.

Experienced designers design plant not for a single duty point, but slightly beyond a design envelope, with enough controllable turn-down for the commissioning engineer to have a bit of capacity in hand.

Having been a commissioning engineer, I know that even on this basis, there are usually a few items which are supposedly comfortably oversized which end up being tuned to run under some operating conditions at the far end of their range.

I'm going to do a few sums to see if the plant as built can be made to work with minor mods, or whether something more radical is needed. My present feeling is that there are pipework modifications which will give a step-change improvement in plant performance.

Unusually the plant has been incredibly well monitored, and the wealth of data on present performance will give a solid baseline, allowing us to know for sure whether our changes have been effective.

Things have been less satisfactory with the Indian Restaurant job, though the owner has now realised that the supposedly septic tank friendly cleaning products he was sold are just the same as the old stuff. He has asked us to specify an alternative, though we sent him the list of EU eco-label products ages ago. We have suggested Ecover, though all of the eco-label products are equal as far as we know.

Hopefully if he starts using that, we might get somewhere. When we visited last week, the tanks were covered in a foot of foam, and several of the distributors which had been blocked by fat carried over by the cleaning chemicals had not been maintained.

Saturday, 6 October 2012

Start of Term and Industrial Effluent Treatment

I have had a couple of busy weeks, with the new intake at Nottingham, as well as picking up and continuing a few jobs - still designing the SCWO plant, starting the new industrial effluent treatment plant, and arranging to go and look at some problems with biological treatment of paper mill waste next Friday.

The Indian restaurant job may be getting back on track after we explained to the client last week what he needs to do to keep his effluent treatment plant running - straight from the British Water Guide.   

I'm really enjoying the mix of work.