SUITMA 2005 Cairo - Biomineralization : a safer environmental and industrial biofilter application
SUITMA 2005 Cairo
| This abstract is about one of the papers of the Consumed mining and military areas theme of the SUITMA 2005 symposium. |
| Ashraf M. Wali,i | Atef Dardir.ii |
- i - Department of Geology, Cairo University, Giza, Egypt
Economic feasibility of extracting salts from Lake Quaroun resembled the requirements for environmental re-balancing of the continuously increasing salinity of the lake water and to conserve its biodiversity. Industrial salt extraction of anhydrous sodium sulfate started by 1993 through brine concentration route via four successive concentration ponds.
Extracting the anhydrous sodium sulfate was achieved through pumping the brine of 336 g/l ± 15 g/l to the plant as a requirement to nucleate glauber salt. Brine specifications of Ca2+ content as not more than 200 ppm is a key-turn to avoid building of scales in both the heat exchanger and the crystallizer units. If the Ca2+ concentration reaches about 300 ppm it causes losses of 4 hours/day of the plant working time for melting and de-scaling the precipitated Ca2+ as gypsum.
Proper pond management of the flowing brines and biomineralization of blue-green and violet algae types succeeded as a bio-filter to mineralize Ca2+ as the algal species turning it into algal mats deposited at the bottom forming a thin calcrete band. The Ca2+ concentration decreased to an average range of 170-190 ppm causing reduction of required time for de-scaling by half. The process proved its efficiency through maintaining constant flow regime and algal population densties in pond no.2, where salinities matches calcium carbonate precipitation, formulates the requirements for consistent regime performance.
The applied process of biomineralization proved its efficiency as a safer environmental approach on industrial scale. The beneficiary economic goals beginning 1996 till the end of 2004 resemble gaining 6500 hours of production. The main goal encloses the direct application of bio-filter concept as a re-cycling of industrializing brines.
