Bioremediation and Detoxification of the Textile Wastewater with Membrane Bioreactor Using the White-rot Fungus and Reuse of Wastewater

BACKGROUND

Application of membrane technology to wastewater treatment has expanded over the last decades due to increasingly stringent legislation, greater opportunities for water reuse/recycling processes and continuing advancement in membrane technology.

OBJECTIVES

In the present study, a bench-scale submerged microfiltration membrane bioreactor (MBR) was used to assess the treatment of textile wastewater.

MATERIALS AND METHODS

The decolorization capacity of white-rot fungus coriolus versicolor was confirmed through agar plate and liquid batch studies. The temperature and pH of the reactor were controlled at 29±1°C and 4.5±2, respectively. The bioreactor was operated with an average flux of 0.05 m.d^-1 (HRT=15hrs) for a month.

RESULTS

Extensive growth of fungi and their attachment to the membrane led to its fouling and associated increase of the transmembrane pressure requiring a periodic withdrawal of sludge and membrane cleaning. However, stable decoloration activity (approx. 98%), BOD (40-50%), COD (50-67%) and total organic carbon (TOC) removal (>95%) was achieved using the entire system (fungi + membrane), while the contribution of the fungi culture alone for TOC removal, as indicated by the quality of the reactor supernatant, was 35-50% and 70%, respectively.

CONCLUSIONS

The treated wastewater quality satisfied the requirement of water quality for dyeing and finishing process excluding light coloration. Therefore, textile wastewater reclamation and reuse is a promising alternative, which can both conserve or supplement the available water resource and reduce or eliminate the environmental pollution.

Ocular health status of chemical industrial workers

BACKGROUND

Approximately 1.2 million workers are employed within chemical industries throughout South Africa. Very little basic data exists regarding the ocular health status and prevalence of occupationally related eye disorders of these workers.

METHOD

A questionnaire was administered and an ocular health examination was carried out on 78 workers in a chemical factory. Workers and the ocular disorders found were then classified according to those exposed and those not exposed to chemicals.

RESULTS

Ocular disorders were more prevalent in exposed workers (73.1%) than in nonexposed workers (43.6%). Statistically significant differences between exposed and nonexposed workers were found with respect to the prevalence of certain anterior segment disorders, viz., tear disorders, dry eye conditions, allergic conjunctivitis, and conjunctival melanosis. In respect to the prevalence of ocular disorders found, 40.8% were attributed to occupational exposure to chemicals.

CONCLUSION

This pilot study shows that further research is required to explore the cause-effect relation between chemical exposure and development of certain anterior segment disorders. Occupational exposure to chemicals should be reduced and exposure protocols at work need to be revised in order to reduce the prevalence of occupationally related eye disorders.

Oral rehydration therapy in a rehydration centre at a teaching hospital in southern Africa

A study was carried out to delineate the use of oral rehydration therapy (ORT) for gastro-enteritis in a unit that had previously used intravenous therapy (IVT) almost exclusively. Most children with dehydrating gastro-enteritis who were 5% or less dehydrated received ORT initially, while those who were more severely affected were given IVT. The success rate using ORT alone was 73%, which was much lower than that achieved in other studies. Possible factors associated with this poor outcome are discussed. It was concluded that with the exceptions of lactose intolerance and coexisting infection, lack of commitment to ORT and the easy access to IVT must have contributed significantly to the suboptimal outcome.