As I wrote in the article, I was far from the first person to visit the site, though I will be the last, as I will actually solve the problem. I can see why people are loath to employ a professional engineer in these cases. Chemical engineers are not cheap, especially not compared with the tanker drivers, farmers, tradesmen and miscellaneous others who are more than willing to have a crack at solving effluent treatment plant problems.
Even when the plant is treating straight domestic sewage, their lack of a systematic and analytical approach makes using non-professionals for troubleshooting a false economy. When the effluent is a complex and variable mixture of sewage and chemical wastes, amateurs should tell the client to call on a professional. If only they would, but it is only professionals are obliged to to work outside their area of competence.