METHOD OF PRODUCING PHOSPHORUS-CONTAINING FERTILISER FROM SLUDGE OF URBAN WATER TREATMENT PLANTS AND FERTILISER PRODUCED USING SAID METHOD Russian patent published in 2014 - IPC C02F11/10 C05B13/00 

FIELD: chemistry.

SUBSTANCE: invention relates to methods of recycling household and industrial wastes, particularly low-waste recycling of sludge formed when treating sewage at urban water treatment plants. The method of producing a phosphorus-containing product for fertilising soil from sludge from urban water treatment plants includes preliminary dehydration of said sludge and heat treatment thereof. Heat treatment of the dehydrated sludge is carried out in two steps: first step - pyrolysis at temperature in the range of 450°C≤T_p≤850°C, second step - burning carbon from the cindery residue in an air current to obtain gaseous products and a mineral phosphorus-containing product. Before heat treatment, the sludge is mixed with additives selected from a group of chlorine-containing salts of alkali and alkali-earth metals.

EFFECT: invention enables to prevent formation of intermediate products which are difficult to process, reduces the amount of effluent gases and improves the degree of removal of heavy metals from the phosphorus-containing product.

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