| 摘要 |
Novelty: production of odorless and cohesive zeolite-sewage sludge suitable for being safely used as a ground improver in agricultural cultivations. Technical features: the natural zeolite is a porous stone rich in HEU-type zeolite (heulandite-clinoptilolite) found in characteristic shards; it contains micro-pores of <20μm, medium pores of from 20 to 100μm, and macro-porous of 100 to 300 μm while its ion-exchange capacity is of the order of 226 meq/100g. The deposition of sewage sludge -which is burdened with gases, bacteria, metals, organic, non-organic and organo-metallic compositions- causes environmental pollution problems. Method of production: Quantities of sewage sludge and natural zeolite fragmented in different granularities (<8mm,<4mm,<2mm, <1mm,<0,5mm) are mixed in the following zeolite/sewage sludge ratios: 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70 and 20:80. The complete mixing of sewage sludge and natural zeolite (in particular zeolite of <0,5mm granularity where the most part of the zeolite shards have been fragmented) sets into full operation the absorption, adsorption and surface deposition of gases , bacteria, organic, non-organic and organo-metallic compositions into the micro-pores and macro-pores of the natural zeolite. The final product is an odorless and cohesive zeolite-sludge mixture. Experiments on washing with deionized water have demonstrated that the noxious components have not been washed out but trapped and confined inside the pores of the natural zeolite. Advantages: compared to the previous state of art where stench and washing of noxious substances contaminating the aqueous environment (surface and subground water) are not prevented, the odorless cohesive zeolite-sludge resulted from the invented method is friendly to plants, humans and environment; it is safe since noxious substances are not washed out by rain water. |
