Three households kept records of their daily waste generation for nine years in Sapporo. The waste was separated into five categories: food waste, trash, plastics, metal, and glass. Recycled material, such as newspaper, was not weighed.
Monthly generation was shown by a median, not by an arithmetic mean because daily generation does not always follow normal distribution, and/or because quite large generation amounts are sometimes produced. Waste generation change by year was closely related to three factors : the use of disposable diapers, the number of family members, and the age of the children. Generation change by month and by week were also both discussed.

View full abstract

N₂O formation and emission behaviors under various conditions as a result of combustion experiments of sewage sludge were examined. As a result of this research, it was ascertained that nitrous oxide was mainly formed by both homogeneous reactions through NCH/NCO and heterogeneous reactions from the direct conversion of char-nitrogen. Maximum N₂O formation occurred around 700°C.
At a temperature higher than 800°C, the destruction of N₂O rapidly occurred with regard to temperature and gas residence time.
Following, the emission behaviors of N₂O from sewage sludge incinerators were measured. The process of N₂O formation as a result of these measurements could be confirmed. It was suggested that the direct conversion of char-nitrogen may play a major role in N₂O formation with regard to sewage sludge incinerators.

View full abstract

From the viewpoint of global warming control, we have studied control of methane gas from waste landfill. There is strong competition for substrates between sulfate reducing bacteria (SRB) and methane producing bacteria (MPB) leading to the possibility of controlling methane gas production by MPB. SRB interference was enhanced with the activity of MPB at the different substrate use by adding sulfate as Na₂SO₄ in the artificial landfill columns.
Over 500 days, since the start-up of the experiments, organic matters were decomposed and converted by MPB to high methane generation (max. conc. 60.2%) in the columns where sulfate was not added.
However, in the columns which received sulfate, organic matters were decomposed and the methane production was controlled by SRB. Most of the CO₂ produced was dissolved in the leachates in the form of inorganic carbon (IC) .

View full abstract

An ion electrode type HCl analyzer was compared through analysis accuracy with the silver nitrate titration method.
Reasons for the difference between HCl concentration measured by the HCl analyzer and the silver nitrate titration method were estimated as follows : The flow rate of gas and absorption solution were slightly varied ; the volume of the absorption solution changed with H₂O condensation from the flue gas in the HCl analyzer ; there was absorption loss of C0₂ into the absorption solution and large dispersion in the silver nitrate titration method.
Because the used solution for absorption of the HCl analyzer contained Hg, it was necesary to remove Hg from used the waste liquid.

View full abstract