In a project to recover phosphorus from night soil, a possible phosphorus resource, composition of major components and toxic substances, and phosphorus together with its chemical form were determined in night soil sludge incineration ash at 14 facilities in Ehime prefecture.
The composition of major components were Al2O3, P2O5, SiO2, Fe2O3, CaO, MgO Na2O and K2O in decreasing order with little seasonal variation. The average phosphorus concentration was about 23.9 wt% calculated as P2O5 and was higher than that of sewage sludge incineration ash. It was found that the concentration of Cd was higher than that in sewage sludge incineration ash but the concentration of toxic substances including Cr, Pb, As, Se and Hg were lower than those in sewage sludge incineration ash.
By X-ray diffraction analysis, it was found that major mineral of night soil sludge incineration ash was phosphate mineral and the average concentration of 14 facilities was 42 wt%. Four species of phosphate mineral were identified, and the concentration of aluminum calcium phosphate was the highest in them. It was thought that in view of included phosphate minerals, acid extraction method was more effective than alkali extraction method．About 80 % of phosphorus was eluted by adding sulfuric acid to pH 2.2.
The significant equation to estimate the recoverable phosphorus quantity from each quantity of night soil and septic tank sludge was obtained by multiple regression analysis.
Eighteen kinds of pesticides at ten sites of rivers and five sites of a bay in Nagoya City were measured every month in 2017 by liquid chromatography tandem-mass spectrometry (LC/MS/MS). The concentrations of the pesticides fluctuated in months and seasons. Also, the concentration profiles of the pesticides fluctuated between months. The data obtained between April and July were analyzed by multivariate analysis. By a cluster analysis, a kind of the multivariate analysis, concentration profiles of the pesticides were discriminated into three types of waters collected in river, sea and the intermediate between river and sea. By the principal component analysis, another kind of the multivariate analysis, the factor 1 was mostly affected by Tricyclazole, Cumyluron and some other pesticides. By the factor analysis, a kind of the multivariate analysis, the common factors affecting pesticides concentration were suggested to be three: the primary factor might be pesticides applied to rice farming, the secondly factor might be those applied to fruit growing, and the third factor might be those applied to vegetable cultivation and fattening pens.
In the analysis of dioxins (PCDDs, PCDFs and dioxin-like PCBs), sulfuric acid treatment is an indispensable process of cleanup. In this study, we found that the disappearance of some TeCDDs, TeCDFs, PeCDDs and PeCDFs by longtime contact with sulfuric acid. No disappearance of these congeners occurs, provided that the sulfuric acid treatment is under gentle conditions of which the analytical manuals have proposed. The disappeared congeners had an unsubstituted benzene ring or a mono-chlorine-substituted one. Furthermore, it was found that sulfonated 1,2,3,4-TeCDD was produced by contacting 1,2,3,4-TeCDD with sulfuric acid. Therefore, it was suggested that the sulfonation reaction occurred in the lower-chlorinated benzene ring. Attention should be paid to sulfuric acid treatment when detailed congener information is required or when using 1,2,3,4-TeCDD and/or 1,2,3,4-TeCDF for sampling spikes. On the other hand, impurities were greatly removed by long-time contact with sulfuric acid. No disappearance was found for congeners with TEF values: Seventeen 2,3,7,8-PCDDs/PCDFs and twelve dioxin-like PCBs.
Activated carbons were derived from cardboard by carbonization, ZnCl2 activation and KOH activation. The ZnCl2- activated carbon samples showed a higher removal of methylene blue from water. The ZnCl2-activated carbon prepared at 600℃ (CB-Z_600) showed a greater adsorption amount of 227 mg/g, that would be directly associated with its well-developed pore properties compared with the other carbon samples. Among several experimental factors examined, the surface area was found to be the most influential factor for methylene blue adsorption onto the prepared activated carbons. It was also revealed that the methylene blue adsorption data were fitted well with the pseudo-second-order kinetics model and Langmuir isotherm model.