污灌土壤中多环芳烃自净的微生物效应

本文研究了不同污灌区各个季节表土和底土中多环芳烃(PAH)含量和微生物生态变化。研究结果表明,PAH总量是表土高于底土,灌水期(7月)高于翻耕前和停灌后。经鉴定的9种PAH以苯并(a)芘、苯并(e)芘和1,2一苯丙蒽含量最低,联苯、萤蒽、芘、苊、菲、蒽较高。其迁移规律是随石油废水中油的输入而吸附于电厂粉煤灰和土壤表层,大量累积于灌渠渠首和附近田块中。污灌区的微生物生态特征是以细菌为主,真菌和放线菌较少。细菌的活性(活细胞数)是表土高于底土,灌水期7月高于4月和9月。细菌的优势种群为芽胞杆菌和假单胞杆菌等。PAH因土壤中的理化和生物因子的作用而消减,并未随灌溉的时间而变化。为了防止PAH累积于农田,在渠首设立吸附过滤沉降池。

SELF-PURIFICATION OF POLYAROMATICHYDROCARBONS AND EFFECT OF MICROBESIN IRRIGATED SOILS

To polyaromatic hydrocarbons (PAHs) were given the highest concerns by public for irrigating paddy fields with refinery wastewater. This study reports self-purification of PAH and microbial biocoenose in surface soil and subsoil during the seasons. Results showed that PAH was higher in surface-layer at irrigation date (July) than before plough and after irragation stopped. BaP, BeP and 1, 2-benzoanthracene were the least in 9 PAHs while biphenyl, fluoranthene, pyrene, acenaphthene, phenanthrene, anthracene were rather high. They were adsorbed on surface soil and fly ash. PAH continuously accumulated in the sediments of channel head and fields nearby.Microbial ecology was mainly characteristic of bacteria but less of fungus and actinomyces. Microbial activity (active cell number) was higher in surface-layer than subsoil, and higher in July than April and September. Predominant microbial biocoenose was bacillus and pseudomonas. Amount of PAH in paddy soil was reduced due to chemical physical and biological factors, and not increased any more even following irrigation time.To prevent PAH from depositing in paddy fields, lagoon adsorption and filter facilities were constructed at channel head as an important way of improving oily wastewater quality.