TREATMENT OF PARBOILED RICE MANUFACTURING WASTEWATER USINGANAEROBIC FIXED FILM FIXED BED REACTOR PACKED WITH SPECIAL MEDIA
Studies on bench scale reactors packed with two different media matrix – Biopac media and Fugino spirals were undertaken to determine the performance at various organic loading rate (OLR) and on one day hydraulic retention time (HRT). Parboiled rice mill wastewater depicted a COD/BOD ratio of 1.6 indicating good degradable nature of the wastewater. Four different organic loadings of 0.8, 1.6, 2.4 and 3.2 kg COD/m3/day were studied in detail. The results indicated BOD and COD removals in the range of 83.0-92.7% and 80.2-89.0% respectively with respect to Biopac media while it ranged between 79.4–90.6% and 76.7–86.1% respectively in case of Fugino spiral media. It is very clear from the results that, Biopac media packed fixed film reactor gave efficient removals compared to Fugino spiral media packed reactor. Volatile acid concentration was well within the congenial range in both the reactors and volatile acid to alkalinity ratio remained well below 0.8 indicating good performance of the reactors. pH of the treated effluent was in the range of 7.1–7.3 indicating good buffering in the system. Daily gas production was measured. This paper discusses in detail the feasibility of upflow anaerobic fixed film fixed bed reactors packed with special media matrix in treating the parboiled rice manufacturing wastewater. Comparative performance of two special media matrix i.e. Fugino Spirals and Special Ultraviolet Stabilized Biopac media in the treatment of parboiled rice manufacturing wastewater has been studied in detail.
BIODEGRADATION OF RICE MILL EFFLUENT BY IMMOBILISED PSEUDOMONAS SP. CELLS
Rice milling is the process of removing the husk and part of the bran from paddy in order to produce edible rice. Rice production, especially parboiled rice production, generally requires a large amount of water for soaking the paddy. This water, if not properly treated, could give rise to water pollution. The limitations in the physico-chemical methods make the biological methods favourable alternatives for the removal of pollutants from the industrial efflu- ents. A bacterial strain was isolated and identified as Pseudomonas sp. through morphological and biochemical tests. Preliminary experiments with Pseudomonas sp. were carried out, using free and immobilised cells. Experi- ments in a packed bed system using immobilised cells indicated a 86.44 % reduction in the COD and a 55.34 % reduction in the BOD after 24 hours. The electrical conductivity, salinity and total dissolved solids were found to decrease to a considerable extent. Studies with varying cell loading showed that a cell loading of 1.7  2.2 mg cells per bead was capable of improving the quality of the rice mill effluent successfully.
Bacterial removal of toxic phenols from an industrial effluent
Chlorinated phenols, widely used in industries, are of growing concern owing to their high toxicity, carcinogenicity and wide distribution in industrial wastes. In the present study, one Pseudomonas isolate, identified as Pseudomonas fluorescens, was obtained using the enrichment process with 2,4,6-trichlorophenol (2,4,6-TCP) as a sole carbon source. This isolate was found to be able to degrade various highly chlorinated phenolic compounds such as pentachlorophenol, 2,4,5-TCP, 2,4,6-TCP as well as phenol, 2,4-dibromophenol and 2,4-dichlorophenol (2,4-DCP). The ability of P. fluorescens isolate to remove phenol from a resin producing industrial effluent was tested by scanning the spectrum with a UV-VIS spectrophotometer. The results indicated that this isolate metabolized phenol in the meta-pathway. The optimal phenol degradation conditions of P. fluorescens isolate were at pH 7 and 30oC. At the 480 mg/l of phenol concentration, the highest specific degradation rate of was observed. Further increases in phenol concentration slowed down the degradation ability of the isolate. However, P. fluorescens isolate still has the ability of degrading phenol at the concentration of 3.2 g/L. The supplementation of 1% glucose stimulated the growth of P. fluorescens isolate and enhanced the ability to utilize phenol from the effluent sample. GC-MS results show that 85.4% of phenol in the effluent sample was metabolized after 40 days. In conclusion, P. fluorescens isolated in this study has the ability of utilizing various chlorophenolic compounds and demonstrates its potentials of degrading high concentration of phenol in industrial effluents.