One potential environmental contaminant produced by both coal coking and indirect coal-to-liquid conversion processes is a class of organic chemicals referred to generically as phenols, or, just "Phenol".
Phenol is present in wastes left behind by older, unregulated coke works, and is among the contaminants that are addressed by cleanup plans and efforts at those sites.
Like the other coal-use "pollutants" we have addressed in our dispatches, Phenol did not have to be, and does not have to be, simply "dumped", or disposed of. It does have industrial uses, such as raw material for some types of epoxy, and other useful, resins.
It's value, in fact, was recognized early in the last century, and some efforts were applied towards recovering it from coal processing installations. As in:
Robert M. Crawford; Ind. Eng. Chem., 1927, 19 (9), pp 966–968
Publication Date: September 1927
Abstract available only through the link."
Keep in mind that coke plant liquid effluents would be similar to those potentially generated by a coal-to-liquid facility employing indirect processes of coal conversion.
However, even though Phenol can be used in industry, it's inherent value and it's concentrations in coal processing effluents are both low enough that most efforts have been directed towards it's straightforward destruction and elimination from the environment. Such Phenol elimination, it seems, can be readily and efficiently accomplished by a wide variety of micro-organisms. That fact has been realized, basically, around the word, as the following references attest:
EL-SAYED Wael S. ; IBRAHIM Mohamed K.; ABU-SHADY Mohamed; EL-BEIH Fawkia; OHMURA Naoya; SAIKI Hiroshi; ANDO Akikazu
Microbiology Department, Faculty of Science, Ain Shams University, Cairo, EGYPTE
Department of Bio-Science, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-city, Chiba 270-1194, JAPON
Department of Science and Technology, Chiba University, 648 Matsudo, Chiba 271-8510, JAPON
Abstract
New phenol degrading bacteria with high biodegradation activity and high tolerance were isolated as Burkholderia cepacia PW3 and Pseudomonas aeruginosa AT2. Both isolates could grow aerobically on phenol as a sole carbon source even at 3 g/l. The whole-cell kinetic properties for phenol degradation by strains PW3 and AT2 showed a Vmax of 0.321 and 0.253 mg/l/min/(mg protein), respectively. "and:
School of Chemical Engineering, Nanjing University of Science & Technology, Nanjing 210094, PR China
Abstract
A white rot fungus Phanerochaete chrysosporium, immobilized with the wood chips of Italian poplar, was employed for biodegradation of phenolic compounds in coking wastewater. The immobilized fungus, dried by vacuum freeze desiccator, was kept high activity after a 9-month preservation and easy to be activated and domesticated. The removal rates of phenolic compounds and COD by immobilized fungus were 87.05% and 72.09% in 6 days, which were obviously higher than that by free fungus. For phenolic compounds biodegradation, a pH ranging from 4.0 to 6.0 and a temperature ranging from 28 °C to 37 °C create suitable conditions, and optimum 5.0 and 35 °C, respectively. The optimum removal rate of phenolic compounds was over 84% and COD was 80% in 3 days. And the biodegradation of phenolic compounds followed the first-order kinetics. It is an efficient and convenient method for coking wastewater treatment."
and:
Increasing the purification ability of a tank for the biochemical purification of phenol waters and flushing liquors
Prokof'ev, V.I. and Kharitonova, N.D,
Moscow Metallurgical Works
Coke Journal, USSR, 1984
Abstract
A biochemical device for purifying flushing liquors and phenol water in operation since 1980 at the by-product coke industry of the Moscow Metallurgical Works is described. Two-stage biochemical purification is realized when water from the recovery house, which goes through mechanical cleaning, is directed into a neutralizer and then into 10 stage-I air tanks where decomposition of the phenols takes place by means of phenol-disintegrating bacteria. The purified water is supplied to a sludge neutralizer. The removal of phenols and rhodanides is ensured up to a concentration of less than or equal to mg/1 and less than or equal to 1 mg/1, respectively."
Even though Phenol emissions can thus be effectively eliminated using "Green" technology, our primary interest is in finding ways in which coal use by-products can be harvested and employed, or recycled. Towards that end, the Indians, perhaps, have presented the most elegant, esthetically-pleasing solution, as follows:
Application and use of water hyacinth for phenol removal and biogas production.
Vaidyanathan, S. - Indian Institute of Technology, Bombay, 1985
Against the background of grave industrial pollution its high cost conventional treatments and energy shortage, different researches, during the past one decade, carried out, extensive exploratory research and began investigating the potential of water hyacinth (Eichhornia crassipes) as a low cost biological system for waste water treatment and for renewable sources of energy. After reviewing the literature available on water hyacinth, research work is planned on the application of water hyacinth for removal of phenol in a continuous unit and use water hyacinth for production of biogas by anaerobic digestion in batch and continuous digesters."
So, we can produce bio-fuel from water hyacinths which consume the phenol by-product of coal processing facilities. And, the hyacinths are lovely floating flowers, by the way. Does this mean that coal plants, by producing this water hyacinth nutrient, can help to beautify Walden Pond?