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0. 05), but both less than that of the lower or stirring excrement (P
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Objective To explore the rela ti onship between the environmental temperature and the oxygen demand of [WT5” BX]Oncomelania snails, and the relationship between the hiber nation or aestivation and the oxygen demand of snails.Me thods The oxygen demand of Oncomelaniasnails between 0 ℃ and 40 ℃ was determined by increasing the temperature gradually in lab, the relationship between the environmental tempera ture and the oxygen demand, and the correlative relationship between the oxygen demand and the percentage of snails in hibernation or aestivation were analysed. Results The oxygen demand increased as the tem perature rose between 1 ℃ and 36 ℃, and the regression equation between the oxygen demand and the variation of environmental temperature was [WT5”BX ]=6.6?10 -5-3?10 -6x+4.4?10 -6x2-8?10 -8x 3(R2=0.998,F=2775,P
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Objective To understand the e ff ectiveness of parasite ova sediment and non-hazardous treatment of two-grille la trines. Methods Two-grille latrines were recon n oitered in the field according to the non-hazardous treatment criteria, and th e sediment of parasite ova, the value of fecal coliform bacteria, NH 3-N, CODcr of the samples from the Grille 1 and Grille 2 of latrines were detected.Results The structure of some two-grille latrines was n o t in accord with the non-hazardous treatment criteria.Parasite ova were detecte d from the Grille 2 of one latrine. Six of 16 latrines were not eligible for non -ha zardous treatment according to the value of fecal coliform bacteria in Grille 2. Conclusion It is not suggested to popularize th e two-grille latrine yet, but it can be used as an interim form for excrement n on-hazardous treatment in rural areas. [
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0.05). There were significant differences among 3- or 6- or 9- or 12-hour groups and 24- or 36-hour groups in 6, 13 ℃ and 28 ℃ respectively (P
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Objective To develop two-grille latrines with the effect of non-hazardous treatment. Methods According to the result of the pretest, one type of two-grille latrines was selected and constructed and its effect of non-hazardous treatment was evaluated. Results The faces-treatment pool, with cement-prefab structure and obturation, had a total cubage of 1.32 m3. The average total amount of faces in the pool was 1.05 m3 per family per month, and the pool could store the faces for over 34 days. The “reaching criteria rate” of the parasite ova sediment and the value of the fecal coliform bacteria were 100% among the excrement in the outlet. Conclusions The prefab two-grille latrines can reach the criteria of non-hazardous treatment, and they can be used in well-off rural areas without the usage of manure.