Chemical removal and recovery of phosphorus from excess sludge in a sewage treatment plant.

We describe a process for the recovery of phosphorus from excess sludge in a sewage treatment plant that currently uses polyaluminium chloride for chemical phosphorus removal. Instead, we employed alkaline dissolution of excess sludge with calcium phosphate precipitation to recover phosphorus from sewage. The recovery ratio for phosphorus from sewage using the phosphorus recovery system is approximately 50%. In addition, the amount of excess sludge in the phosphorus recovery system is approximately half that of conventional chemical phosphorus removal. Alkaline dissolution of excess sludge resulted in dissolution of aluminium into the supernatant. Furthermore, since dissolved aluminium can be reused as a coagulant, the phosphorus recovery system could be used to economize coagulant consumption. Operation and maintenance costs of the phosphorus recovery system are 25.9 U.S. cents per 1 m3 of sewage compared to 32.0 U.S. cents per 1 m3 of sewage for conventional chemical phosphorus removal, representing a decrease of 20% in the operation and maintenance costs.

Effect of dietary fat and fiber on fecal flora, bacterial metabolites, and fecal properties in Japanese volunteers.

The effects of dietary fat and dietary fiber (DF) levels in diet on fecal flora, activities of three fecal enzymes, putrefactive metabolites, fecal mutagenicity and fecal properties were studied in eight healthy volunteers. They were given low fat and low DF diet (LF: fat energy ratio was 13.9%, and DF intake was 9.0 g/day) for 10 days, high fat and low DF diet (HF: fat energy ratio was 52.7%, and DF intake was 7.1 g/day) for 10 days, and high fat and high DF diet (HFF: fat energy ratio was 52.0%, and DF intake was 24.8 g/day) for 10 days. No change of fecal flora at the bacterial group level was observed throughout the experimental period, except that the population of lactobacilli showed a tendency to increase in HF period. Fecal activities of beta-glucuronidase, beta-glucosidase and nitroreductase and some putrefactive products were unchanged between LF and HF, while these values decreased in HFF period. No significant change of fecal properties was observed between LF and HF, while by HFF supplementation fecal weight increased and fecal pH value was lower than that in LF and HF. Excretions of iron, zinc and calcium in feces did not increase by high DF supplementation.

Amino acid sequence of cyanogen bromide fragments of potato phosphorylase.

Amino acid sequence analysis of the cyanogen bromide peptides of potato alpha-glucan phosphorylase was undertaken for comparison with rabbit muscle glycogen phosphorylase and for elucidation of the structural bases for the differences in the catalytic and regulatory properties between the animal and plant enzymes. The potato enzyme was carboxymethylated and cleaved with cyanogen bromide. The 17 distinct fragments produced were isolated by a combination of gel filtration, sulfopropyl ion exchange chromatography, and high performance liquid chromatography. The molecular weights of these fragments are distributed in a range of 300 to 30,000. Fragment CI has a blocked amino terminus, and has the same amino acid sequence as CII, which has been assigned as the amino-terminal fragment of potato phosphorylase. The blocking group was deduced to be an acetyl group from the results of fast atom bombardment mass spectrometry of an amino-terminal pentapeptide. This paper describes the sequence determination of all the cyanogen bromide fragments of potato phosphorylase. The complete structure is presented in the following paper (Nakano, K., and Fukui, T. (1986) J. Biol. Chem. 261, 8230-8236).