Novel technology for sewage sludge utilization: preparation of amino acids chelated trace elements (AACTE) fertilizer.
This study developed a novel technology for sewage sludge utilization. The bacteria proteins in the sewage sludge were extracted to produce the amino acid chelated trace elements (AACTE) fertilizer by virtue of several chemical processes. Firstly, the sewage sludge was hydrolyzed under hot hydrochloric acid solution to obtain protein solution. The effects of hydrolysis temperature, reaction time and pH on the extraction ratio of protein from the sewage sludge were investigated. Secondly, the protein solution was further hydrolyzed into amino acids under hot acid condition. The effects of the HCl dosage, hydrolysis temperature and reaction time on the yields of amino acids were investigated in detail. Thirdly, the raw amino acids solution was purified by activated carbon decolorization and glacial acetic acid dissolution. Finally, the purified amino acids were used to produce the AACTE fertilizer by chelating with trace elements. Results showed that, under optimum hydrolysis conditions, 78.5% of protein was extracted from the sewage sludge and the amino acids yield was 10-13 g per 100g of dry sludge. The AACTE fertilizer produced was in accordance with China Standard for Amino Acids Foliar Fertilizer. This novel technology is more environmentally friendly compared with the conventional sludge treatments.
Liu
Yangsheng
Y
College of Environmental Science and Engineering, Peking University, Beijing 100871, China. yshliu@pku.edu.cn
Kong
Sifang
S
Li
Yaqiong
Y
Zeng
Hui
H
D000596:Amino Acids / Q000737:chemistry*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D005308:Fertilizers; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D019216:Metals, Heavy / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013696:Temperature; D014131:Trace Elements / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis; D018508:Water Purification / Q000379:methods
D000596:Amino Acids; D005308:Fertilizers; D019216:Metals, Heavy; D012722:Sewage; D014131:Trace Elements; D014874:Water Pollutants, Chemical