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Leachate Quality from Acidic Mine Spoil Fertilized with Liquid Digested Sewage Sludge
Author(s) -
Peterson J. R.,
Gschwind John
Publication year - 1972
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1972.00472425000100040016x
Subject(s) - leachate , leaching (pedology) , chemistry , environmental chemistry , sewage sludge , ammonium , pulp and paper industry , environmental engineering , environmental science , sewage , soil water , soil science , engineering , organic chemistry
The leachate quality from an acidic mine spoil was upgraded by the addition of liquid digested sludge. Mixing liquid sludge with acidic spoil material (pH 2.5) at a w/w ratio of 1:37 (61 metric tons/ha, dry basis), reduced leachate constituents as follows: total acidity, 17%; Al, 99%; Fe, 80%; and soluble salts, 41% for this 110‐day study. During this period leachate showed increases in: NH 3 ‐N, 1689%; SO 4 , 49%; Zn, 1941%; and Mg, 827%. The pH of this leachate increased immediately to 4.6 (check column remained near 2.5) and continued with a gradual neutralization. The mixing of sludge with this spoil material at a w/w ratio of 1:18 (122 metric tons/ha, dry basis) was the second most efficient for water amelioration. This leachate had an immediate pH increase of 4.5 and an eventual increase to pH 8, a 99% reduction in Al, an increase in NH 3 ‐N by 3131%, and total P by 1069% over the check column leachate. A third ratio of sludge to acidic soil of 1:37 mixed in the top quarter of the column showed the least leachate amelioration, but after 30 days of leaching, nitrification began in this column, indicating aerobiosis and a pH of > 5.4 in a part of the soil column. The columns were leached 1 hour/day with 1.36 cm of aerated deionized water so that unsaturated flow occurred during a part of each day.