Palm oil refinery wastes treatment

Effluent from the refining of crude palm oil was subjected to physical-chemical and biological treatment. An inclined corrugated parallel plates oil separator spaced at 25 mm was used with hydraulic loading rates ofO.2. 0.5 and I m³ mol_h. 91% oil and grease removal could be achieved at 0.2 m³ m–2 _h. Coagulation and flocculation carried out on batch samples after oil and grease separation revealed that with 100 mg 1- I alum addition BOO was reduced from 3500 to 450 mg 1–1 and COD from 8600 to 750 mg 1–1 after 30 min settling. Higher doses of alum and doses of polyelectrolyte, activated carbon and sodium hypochloride did not yield significant additional reductions in BOD and COD. Batch dissolved air flotation (OAF) removed 90% of the suspended solids with 2.7% solids in the thickened sludge at an A/S ratio of 0.014. This method yielded the similar effluent quality as the inclined corrugated plates oil and grease separator. Field data from a OAF plant compare closely with data achieved in this study. Activated sludge treatment on the effluent from the oil separator yielded a BOD of 46 mg I–1 with a loading rate of OJ g BOD (g MLVSS) –1 day. Total dissolved solids (TDS) remained high and removal through coagulation and chemical oxidation brought the COD level down to around I80mg I–1 Biokinetic coefficients Y. lid' K and K, were found to be 0.S5 g VSS (g BOD) –1. 0.016day–1. 0.12 g BOD (g VSS) –1 <day and 510 mg 1–1 BOD respectively

Coherent Collisions between Bose-Einstein Condensates

We study the non-degenerate parametric amplifier for matter waves, implemented by colliding two Bose-Einstein condensates. The coherence of the amplified waves is shown by observing high contrast interference with a reference wave and by reversing the amplification process. Since our experiments also place limits on all known sources of decoherence, we infer that relative number squeezing is most likely present between the amplified modes. Finally, we suggest that reversal of the amplification process may be used to detect relative number squeezing without requiring single-particle detection.Comment: 4.2 pages, 4 figures, please take postscript version for best quality of picture

Dissociation and Decay of Ultra-cold Sodium Molecules

The dissociation of ultracold molecules is studied by ramping an external magnetic field through a Feshbach resonance. The observed dissociation energy shows non-linear dependence on the ramp speed and directly yields the strength of the atom-molecule coupling. In addition, inelastic molecule-molecule and molecule-atom collisions are characterized

Sigma and omega meson propagation in a dense nuclear medium

The propagation of the scalar ($\sigma$) and vector ($\omega$) mesons in nuclear matter is studied in detail using the Walecka model over a wide range of densities and including the effects of a finite $\sigma$ width through the inclusion of a two-pion loop. We calculate the dispersion relation and spectral functions of the $\sigma$ and (transverse and longitudinal) $\omega$ mesons, including the effect of $\sigma$-$\omega$ mixing in matter. It is shown that the mixing effect is quite important in the propagation of the (longitudinal) $\omega$ and $\sigma$ mesons above normal nuclear matter density. We find that there is a two-peak structure in the spectral function of the $\sigma$ channel, caused by $\sigma$-$\omega$ mixing.Comment: 17 pages including 6 ps files, submitted to Phys. Lett. B. Acknowledgement is revise