Grey Wool Knickers They breathe

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Today we had a visit from Edward Smith, a professor in AUC’s Construction and Environmental Engineering department. He informed us about the particulars of pollution and water quality management on the Nile through a very well-organized lecture. Almost too organized. He first handed out an information packet with blanks to be filled in throughout the lecture. He then proceeded with a PowerPoint presentation, from which he deviated very little. I rather prefer Rick Tutwiler’s lectures because, even though they are structured around the PowerPoint format, he wanders off-subject enough to make it feel like we’re being educated, and not just instructed.

Nevertheless, I did like Ed Smith’s lecture and was grateful to learn more about how environmental engineers evaluate and mitigate water pollution. On the evaluation side, much of the particular jargon of the field was familiar to me from living for quite a while in the environmentally-conscious beach/riparian community of Santa Cruz, California. But, it was helpful to learn more about how those fecal coliform measurements were made and what they actually mean. For instance, I had been previously unaware that E. coli was just used as an indicator (or “surrogate”, in the particular language of environmental engineers) for a wide variety of micro-organisms that it would be prohibitively expensive to test for. I also gained a fuller understanding of pH in water, although the presentation on this was necessarily quite abbreviated, leaving me still a bit confused.

One of the pieces of information I found of greatest use was about the greater level hardness of the water in Cairo, compared to most municipal water systems. I was already somewhat aware of this because of the deposits of Calcium and Magnesium in our teapot whenever we boil water (which we do quite often to evaporate all the chlorine in the water, which I learned is also higher here than in most water systems). In addition to this, Ed Smith also explained that hard water “complexes soaps.” I’d never heard “complex” used as a verb, but it means that it suppresses the suds. I had been wondering why it seemed like I needed to use more soap here in the shower to get a lather. It turns out I don’t need to use more soap at all, as it cleans just as well.

It was also fascinating to learn about how water treatment plants work, and Ed Smith in fact gave us a tour of the lab where much of the water quality research at AUC is performed. A bit of information I found fascinating and a bit disturbing is that the wastewater treatment plant on the west bank of the Nile in Giza is so completely overloaded that a full 40% of the wastewater by-passes the plant entirely, whereupon it is discharged into the Nile.

A large issue that Ed Smith lectured about, and which was completely new to me, was the phenomenon of Disinfection By-Products (or DBPs) which result from chemical interactions between Natural Organic Matter (NOM) and Chlorine. The US EPA has established what it considers safe levels of such DBPs (based as much on the economic feasibility of mitigation measures as on data from epidemiological studies), and Egypt also has some standards, but they are not as stringent, nor do they cover as many classes of DBPs as the US standards. The health effects of DBPs include cancer (especially bladder cancer), central nervous system (CNS) depression, hepatitis and slowing down of normal brain activity. Ed Smith was involved in a study (funded by BP Egypt) regarding levels of DBPs in Cairo’s municipal water at various places and found that the levels were often above Egypt’s acceptable levels and almost always above US standards. He also conducted a study (also funded by BP Egypt) on the effectiveness of various kinds of household water filters in removing the DBPs. In addition, he indicated that, since DBPs are volatile compounds, they can be evaporated off, so our boiling of the water can be of help (although, as he pointed out, we might then be breathing the DBPs instead of drinking them, and they can also be absorbed through the skin when taking a shower or whatever). Of course, bottled water isn’t much better.

But enough of the acronyms. At the end of the lecture, before heading to the lab for an illustration of flocculation, making E. coli cultures and doing spectrum analysis on water samples, Doctor Rick asked Ed Smith the question, “how has the building of the High Dam effected water quality in the Nile?”. To Rick’s apparent surprise, the answer was not that it had worsened it overall. On the one hand, the annual cycles of the Nile flood no longer result in the desiccation and killing of harmful pests and disease vectors or the flushing of more persistent pollutants. On the other hand, there are no more dry periods during which harmful discharges would be concentrated because of low water flows (they are now diluted by year-round flows), nor does the river rise high enough, or unpredictably enough, to allow the containment of septic or polluted areas to be breached (pollutants can be contained on dry land). I won’t claim to know enough to comment on this.