Beer lees are a waste discharged in a large amount from a beer brewery. In order to convert beer lees to valuables, we have carried out the investigations for the production of beer lees charcoal, the evaluation of burning characteristics of the charcoal and the application of the charcoal to water purification. Beer lees contain 4.4% ash and the ash content of beer lees charcoal is 11.9%. The dissolution phenomena of minerals such as Zn, Fe, Ca, Mg, K, Na etc. from beer lees, beer lees charcoal and beer lees ash were examined by using lactic, tartaric and citric acid solutions as a solvent. The organic acids contained in natural plants were used for this purpose, as the dissolved solution may be used for food additives. These acids are considered to be effective for the dissolution of minerals due to the complex formation ability. The obtained results were evaluated using the conditional stability constants between minerals such as Zn, Ca and Mg, and the organic acid.
The environmental problems of eutrophication in the closing area of the sea increased oxygen demands in surface water and acidification. Total nitrogen and phosphorous are responsible for an eutrophication and the advanced sewage treatment for nitrogen is more necessary. We used the polysulphone hollow fiber with pore of 0.1 mm as the supporter for the BOD oxidizing bacteria, nitrifying bacteria and denitrifying bacteria. These bacteria were immobilized on the surface of the hollow fiber through the medium of polyvinyl alcohol. The fiber modules were furnished in the tubular reactor and the sewage was introduced to the outer surface of the fiber. Oxygen for BOD oxidation and nitrification and nitrogen for denitrification were delivered from the hollow fiber's inner side. The continuous sewage treatment was put in operation by combination of the hollow fiber reactor in series, that is BOD oxidation reactor, nitrification reactor and denitrification reactor. When the artificial wastewater containing BOD (100 mg-BOD/L) and ammonium sulfate (20 mg-N/L) was fed, BOD oxidation rate of 10 g-BOD/m2/h, nitrification rate of 0.35 g-N/ m2/h and denitrification rate of 0.4 g-N/m2/h were attained. These rates were higher than the standard activated sludge process. Consequently, the hollow fiber reactor was considered very effective for removal of BOD and nitrogen in the sewage. Since superiority of hollow fiber bioreactor was demonstrated in laboratory, we installed the bioreactor about 20 times as large as laboratory scale reactors in the sewage treatment plant and conducted feasibility study by integrated continuous sewage treatment. Thus we have confirmed the bioreactor of the present method to be applicable to the treatment of actual sewage.
A novel process for effectively recovering phosphorus from waste has been developed. By this process, magnesium ammonium phosphate (hereinafter referred to as MAP) is recovered from anaerobic digestive sludge in sewage. The MAP recovery process involves recovering inorganic fine particles, which include the MAP particles, from digestive sludge through a successive line of separating devices such as, a vibrating screen, a hydro-cyclone, and a revolving-cylindrical type thin flow separator or multi-gravity separator. Continuous tests for MAP recovery carried out to study the performance of this process indicate that it was possible to recover about 90% of MAP.