In Finland the thermal treatment of sewage sludge has been moderate in 21th century. Thereason has been the high moisture content of sludge. During 2005-2008, 97-99% of sewagesludge was utilized in landscaping and agriculture. However agricultural use has been during2005-2007 less than 3 %. The aim of national waste management plan is that by 2016 100%of sludge is used either as soil amendment or energy. The most popular utilization methodfor manure is spreading it on arable land. The dry manures such as poultry manure and horsemanure could also be used in incineration. The ashes could be used as fertilizers and while itis not suitable as a starter fertilizer, it is suitable in maintaining P levels in the soil. One ofthe main drivers for more efficient nutrient management is the eutrophication in lakes andthe Baltic See.ASH DEC process can be used in concentrating phosphorus rich ashes while separating theheavy metals that could be included. ASH DEC process uses thermochemical treatment toproduce renewable phosphate for fertilizer production. The process includes mixing of ashesand chlorine donors and subsequent treatment in rotary kiln for 20 min in temperature of 900– 1 050 oC. The heavy metals evaporate and P-rich product is obtained. The toxic substancesare retained in air pollution control system in form of mixed metal hydroxides.The aim of conducting this study is to estimate the potential of ASH DEC process in treatingphosphorus rich ashes in Finland. The masses considered in are sewage sludge, dry manurefrom horses, and poultry and liquid pig manure.To date the usual treatment method for sewage sludge in Finland is composting or anaerobicdigestion. Part of the amount of produced sewage sludge (800 kt/a fresh mass and 160 kt/aTS) could also be incinerated and the residual ashes used in ASH DEC process. Incineratingonly manure can be economically difficult to manage because the incineration of manure isin Finland considered as waste incineration. Getting a permit for waste incineration isdifficult and also small scale waste incineration is too expensive. The manure could act as anadditional feedstock in counties with high density of animal husbandry where the land areamight not be enough for spreading of manure. Now when the manure acts as asupplementary feedstock beside sludge, the ash can’t be used directly as fertilizer. Then itcould be used in ASH DEC process. The perquisite is that the manure producers could payfor the incineration, which might prove problematic.
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