悬浮结晶法预处理敌草胺生产废水

采用悬浮结晶法对敌草胺生产废水进行焚烧前预处理,研究了不同成冰率条件下废水的处理效果,并对冷冻过程中的析出晶体进行了表征。在成冰率为61.3%时,出水COD、色度和电导率的去除率分别可达94.0%、99.2%和89.1%。出水pH为9～10,满足后续生化处理的pH要求。在成冰率为61.3%时,一级浓缩液热值较原水增加了129%,且焚烧量大幅下降。析出晶体的主要组分为KCl和脂肪族酰胺。在成冰率为61.3%时,每处理1 t原水可回收89 kg析出晶体,具有较好的资源化利用前景。     

Alteration of microbial properties and community structure in soils exposed to napropamide

The effect of pesticide napropamide (N,N-diethyl-2-(1-naphthalenyloxy) propanamide) on soil microorganisms for long-term (56 d) was assessed by monitoring changes in soil microbial biological responses. Soils were treated with napropamide at 0, 2, 10, 20, 40, and 80 mg/kg soil and sampled at intervals of 1, 3, 7, 14, 28, 42, and 56 d. The average microbial biomass C declined in napropamide-treated soils as compared to control. The same trend was observed on microbial biomass N after napropamide application.We also determined the basal soil respiration (BSR) and observed a high level in soils treated with napropamide during the first 7 d of experiment. But with the passage of incubation time, BSR with napropamide decreased relatively to control. Application of napropamide at 2–80 mg/kg soil had inhibitory e ects on the activity of urease and invertase. Activity of catalase was enhanced during the initial 7 d of napropamide application, but soon recovered to the basal level. The depressed enzyme activities might be due to the toxicity of napropamide to the soil microbial populations. To further understand the e ect of napropamide on microbial communities, a PCRDGGE- based experiment and cluster analysis of 16S rDNA community profiles were performed. Our analysis revealed an apparent di erence in bacterial-community composition between the napropamide treatments and control. Addition of napropamide apparently increased the number of bands during the 7–14 d of incubation. These results imply that napropamide-induced toxicity was responsible for the disturbance of the microbial populations in soil.