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The disposal of leather tannery wastes by land treatment—a review
Author(s) -
Hughes J.C.
Publication year - 1988
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/j.1475-2743.1988.tb00745.x
Subject(s) - environmental science , irrigation , groundwater , waste management , nitrate , sewage sludge , environmental engineering , agronomy , sewage , chemistry , geology , geotechnical engineering , organic chemistry , biology , engineering
. People in rural areas have disposed of their wastes on land for centuries, relying on the soil's ability to degrade and render harmless any toxic elements the wastes may contain. Leather tanneries produce a large amount of sludge and liquid wastes. The liquids contain much sodium and in most circumstances adversely affect both the soil and groundwater. However, in some countries they are used for irrigation. The sludges contain nitrogen, calcium, magnesium, phosphorus, trivalent chromium and some sodium. Given careful management these sludges can be used as soil amendments, either directly or after composting. Application rates of about 200 tonnes ha −1 have proved toxic to crops in pot trials, though larger applications than this have not adversely affected crops in the field. Much smaller rates, of less than 20 tonnes ha −1 , have been used in the field to minimize nitrate contamination of groundwater. The effects of CrIII depend on complex interactions between the sludge, the soil to which it is added and the plant species grown. Safe limits for the disposal of the sludges and their long term effects are not known.