|Sludge composting project put into operation
|Dongying guangmao chemical technology co., LTD 2013-01-21 19:22:05 作者:SystemMaster 来源: 文字大小:[大][中][小]
| Technological base for high-temperature composting
The sewage sludge harmless agricultural technology is a key technology to address the issue that the dewatered sludge with high moisture content is not suitable for fermentation, through researching the properties of fly ash of power plant and absorbing the research technologies of ETH / OAM Recycling Company for fly ash and sludge applied in the German agriculture, on the basis of high-temperature composting technology. The technological process is as follows: uniformly mix the dewatered sludge with the added substances at a certain proportion, and than at a certain temperature, dewater the sludge and solidify organic matters through composting. The basic raw materials for this technology include sewage sludge and fly ash produced from power plants as well as necessary nutrients added and additives according to the requirements of different crops. With the simple equipment, sterilization, eggs killing and heavy metal solidification can be achieved without any special drying equipment in the production process. Pearlescent rock, diatomite, zeolite and gypsum waste (desulfurization byproducts of power plant and boiler room), etc. may also be added in the additives and the PH value of the prepared fertilizer is adjusted by adding lime.
The experiments show that fly ash contains a variety of trace elements beneficial to plant growth, with strong hydration as well as other features such as promoting fermentation and improving soil nature. It also has sustained release to fertilizer applied to farmland and heavy metals. Therefore, if the fly ash is disposed as one main dry component in sewage sludge, the harmless agricultural effect of sewage sludge can not only be increased, but a new path for utilizing fly ash is developed.
The granular fertilizer produced by means of this technology has low water content, easy to store, transport and spread in farmland. According to the experiment results, compared with the efficient phosphate fertilizer (DAP) with the same valence, the yield can increase by 10~20%. The additives can loosen soil, increase the viscosity of soil grains, and enhance fertilizer effect and protect soil. As the fertilizer additive has solidification effect, the granular fertilizers have some resistance to water and flushing, to achieve the sustained release effect and prolong the fertilizer effect.
According to the requirements of China"s agriculture and forestry production, two series of organic compound fertilizers have been developed by using the sludge harmless agricultural technology.
Soil conditioner is mainly used to improve soil and forest planting; its main components include organic matters of 25 ~38% and P, N, K more than 7% .
Granular compound fertilizer is mainly used for field planting; its components include organic matter of 10 ~ 20% and P, N, K of 20 ~ 25%; it meets the national standard GB15063-94.