Rubber and methane recovery from deproteinized natural rubber wastewater by coagulation pre-treatment and anaerobic treatment

A newly developed natural rubber deproteinization process produces deproteinized natural rubber [DPNR] wastewater as an intermediate product containing a high concentration of sodium dodecyl sulfate [SDS] and rubber. In this study, a novel process to recover the residual rubber and energy as methane from DPNR wastewater was developed. As a pretreatment, SDS and residual rubber in DPNR wastewater were coagulated and recovered by addition of CaCl[2] at Ca[2+]/SDS and Ca[2+]/rubber mass ratios of 0.070 and 0.055, respectively. The remaining organic matter in the pre-treated DPNR wastewater was converted to methane by using a mesophilic up-flow anaerobic sludge bed [UASB] reactor. The UASB reactor with the diluted pre-treated DPNR wastewater showed a total chemical oxygen demand [COD] removal efficiency of 92 +/- 2% at a maximum loading rate of 6.8 +/- 1.8 kgCODm[-3]d[-1] at a hydraulic retention time [HRT] of 12 h. Under the condition of effluent recirculation with raw pre-treated DPNR wastewater, the UASB reactor showed a total COD removal efficiency of 84 +/- 8% at the maximum loading rate of 6.4 +/- 1.7 kgCODm[-3]d[-1] at HRT of 39 h. The results suggest that the newly developed resource recovery process for DPNR wastewater could be a promising treatment system

Present status of trichinellosis in Japan.

There have been three mass outbreaks of human trichinellosis in Japan. The first was in 1974 in Iwasaki, Aomori Prefecture, involving a group of hunters who ate raw meat of a black bear they had shot. Of the 20 people who ate the bear meat raw, 15 showed clinical symptoms of trichinellosis. The second outbreak was experienced in Sapporo, Hokkaido, in 1980. The patients had eaten the raw meat of a brown bear served in a local restaurant. Twelve people were diagnosed positive on the basis of clinical symptoms and the results of serological tests. The third outbreak was reported in 1982. Of the 434 people who had eaten raw black bear meat at a local restaurant in Yokkaichi, Mie Prefecture in December 1981, 60 were diagnosed as positive for trichinellosis. The first finding of Trichinella spiralis in Japan was in 1957, when the parasite was detected in a formalin-preserved specimen of an indigenous dog in Sapporo, Hokkaido. Since then T. spiralis infection has been reported in imported animals, such as mink (1957), polar bears (1960, 1969, 1986), tiger (1986), and black leopard (1986). To date, spontaneous infection of T. spiralis in wildlife in Japan has been reported in sables (in Hokkaido, 1963), Japanese black bear (in Aomori, 1974, 1975), brown bear (in Hokkaido, 1980) and raccoon dog (in Yamagata, 1984).

Scrub typhus and chiggers in northern Thailand.

It was reconfirmed that L. deliense was the most dominant chigger during the rainy season in northern Thailand. Overall prevalence of IgG antibody against R. tsutsugamushi among the rural villagers in the northern most part of Thailand was nearly 60% at the level over 1 : 10 by an indirect immunofluorescent test. The level of IgG and IgM antibody titers was considerably high as greater than or equal to 1 : 2560 in some sera, but did not markedly vary by age groups or sexes. Based on detection of IgM antibody, the probability of new or reinfections were considered.