云南玉溪烟区轮作与连作土壤细菌群落多样性比较研究

为评价云南玉溪烟区轮作和连作对土壤细菌群落多样性影响,从土壤中直接提取土壤细菌总DNA,用细菌16S rDNA特异性引物进行PCR扩增和变性梯度凝胶电泳(DGGE),每个处理样品3次重复,在DGGE图谱中相似性较高,基本聚在一起,从整体证明了试验操作方法较为精确.从泳道分析图可知,轮作土壤细菌群落各泳道条带数量13～29条不等,平均为21条.连作土壤细菌群落各泳道条带数量从4～20条不等,平均为12条.从每条泳道的条带数方面和光密度值分别进行细菌群落多样性各指标的比较,结果表明,轮作处理细菌群落丰富度指数均大于连作处理,轮作香农-威纳和辛普森指数(1/D)均大于连作,表明轮作微生物多样性较连作高,轮作方式可以提高植烟土壤细菌群落的多样性.     

复合多管除尘器在湿法水泥回转窑除尘中的应用

把具有惯性沉降除尘、旋风子除尘两级一体功能的复合多管除尘器用于带湿式蒸发器的湿法水泥回转窑尾气除尘，替换原“旋风除尘器＋电除尘器”除尘系统中的多筒旋风器。运行测试表明，它的除尘效率达到９４６％，确保了窑尾排放烟尘浓度达到国家标准。     

义乌市城镇污水提标处理的环境与经济效益分析

自2014年以来,浙江省义乌市全面推进城镇污水治理工作,在城镇污水提标处理方面开展了诸多实践。以义乌市2015年和2017年施行的污水排放标准为情境要素,结合该市9座污水处理厂实际运行数据及能耗、化学药剂和污染物排放的生命周期环境影响清单数据,模拟分析了义乌市城镇污水提标处理的环境和经济效益。结果表明,义乌市污水提标处理虽然有益于水体污染物减排,但由于既有污水处理厂普遍进水碳源不足,污水二级处理工艺需仰赖增加化学药剂投放来进行强化,使得投入了大量资金的污水提标处理并未能真正有效地解决水体污染问题,而且还会在气候变暖、土壤酸化、土壤生态毒性等方面产生负面影响。进一步地,围绕污水提标处理的强效思路、污水过度处理负面效应的缓解对策、及污水处理经济效益的增收策略进行了展望,以期为义乌市乃至我国构建经济高效、绿色低碳的污水治理模式提供参考。     

湖南主要农田土壤中氮的形态

本试验采集了湖南省八种主要母质发育的２３个农田土壤耕层样本，其中水田土壤１６个，旱地土壤７个．将土壤氮分为七级．即交换性ＮＨ４＋十ＮＯ３－，水解性ＮＨ４＋，氨基糖氮，可溶性碱稳定态氮，酸溶性腐殖质态氮，固定态ＮＨ４＋，难溶性腐殖质态氮。分析结果表明，土壤中交换性ＮＨ４＋十ＮＯ３－的含量为２２．０土９．０ｍｇ／ｋｇ，占全氮的１．７土０．７％；水解性ＮＨ４＋为３２４．４土１０９．５ｍｇ／ｋｇ，占全氮的２３．９±５．６％；氨基糖氮为１１８．９土４３．０ｍｇ／ｋｇ，占全氮的９．１土３．２％；可溶性碱稳定态氮为４９７．１土２０５．８ｍｇ／ｋｇ，占全氮的３６．２土８．３％；酸溶性腐殖质态氮为２９．２土１０．２ｍｇ／ｋｇ，占全氮的１３土０．８％；固定态ＮＨ４＋为４７．２土２４．３ｍｇ／ｋｇ，占全氮的３．６±１．７％；难溶性腐殖质态氮为３４１．３土２７０．８ｍｇ／ｋｇ，占全氮的２２．２土１１．６％。     

炼钢废气除尘污水处理的研究

系统地研究了影响石灰中和法处理转炉除尘废水含铜沉降速度的因素.结果表明,在搅拌时间10 min和中等搅拌强度的条件下,pH值控制在8.2～9.0范围内能使废水中铜含量在1 h的沉降时间内降至国家排放标准2 mg/L以下.实验还研究了在石灰中和过程中加入适量絮凝剂的影响因素.结果表明,在搅拌时间3 min和相同pH值范围的条件下,加入絮凝剂能使废水中铜含量在30 min的沉降时间内降至国家排放标准2 mg/L以下.     

Source identification and prediction of nitrogen and phosphorus pollution of Lake Taihu by an ensemble machine learning technique

● A machine learning model was used to identify lake nutrient pollution sources. ● XGBoost model showed the best performance for lake water quality prediction. ● Model feature size was reduced by screening the key features with the MIC method. ● TN and TP concentrations of Lake Taihu are mainly affected by endogenous sources. ● Next-month lake TN and TP concentrations were predicted accurately. Effective control of lake eutrophication necessitates a full understanding of the complicated nitrogen and phosphorus pollution sources, for which mathematical modeling is commonly adopted. In contrast to the conventional knowledge-based models that usually perform poorly due to insufficient knowledge of pollutant geochemical cycling, we employed an ensemble machine learning (ML) model to identify the key nitrogen and phosphorus sources of lakes. Six ML models were developed based on 13 years of historical data of Lake Taihu’s water quality, environmental input, and meteorological conditions, among which the XGBoost model stood out as the best model for total nitrogen (TN) and total phosphorus (TP) prediction. The results suggest that the lake TN is mainly affected by the endogenous load and inflow river water quality, while the lake TP is predominantly from endogenous sources. The prediction of the lake TN and TP concentration changes in response to these key feature variations suggests that endogenous source control is a highly desirable option for lake eutrophication control. Finally, one-month-ahead prediction of lake TN and TP concentrations (R² of 0.85 and 0.95, respectively) was achieved based on this model with sliding time window lengths of 9 and 6 months, respectively. Our work demonstrates the great potential of using ensemble ML models for lake pollution source tracking and prediction, which may provide valuable references for early warning and rational control of lake eutrophication.     

常规组合工艺-稳定塘-湿地系统处理印染废水

针对工业园区印染企业产生的印染废水和生活污水,采用独特的"常规组合工艺与‘植物稳定塘-人工湿地系统’联合工艺"对其进行集中统一处理,并考察了运行效果。数据结果表明,系统出水COD、BOD5、SS、色度、NH3-N和TP平均分别为63.2 mg/L、13.8 mg/L、5.0 mg/L、49倍、0.2 mg/L和0.4 mg/L,出水水质达到国家污水综合排放一级标准(GB8978-1996)。该工艺运行稳定,可有效去除废水中的COD、SS和色度,去除率均在90%以上。按日均处理量4×104m3计算,此工艺每年将削减COD排放近30万t。     

AHLs群体感应信号分子对活性污泥反应器处理高氨氮废水的影响

硝化细菌生长缓慢、同化效率低、环境敏感性高,并且高氨氮废水中存在大量的游离氨会对硝化细菌活性产生抑制作用。本实验采用序批式反应器,研究添加C7-HSL、C8-HSL和3-oxo-C10-HSL对活性污泥处理高氨氮废水的影响。结果表明,信号分子可以显著促进微生物的生长,有效提高亚硝酸盐氧化菌(nitrite-oxidizing bacteria,NOB)的活性,同时可促进胞外聚合物(extracellular polymeric substance,EPS)的形成,改变EPS的组成,从而有效缓解高${{\rm{NO}}_2^{-}} $-N对系统的抑制,说明信号分子有利于微生物对抗不利的环境条件,缩短系统达到稳定的时间。其中C7-HSL效果最显著,污泥平均生长速率提升35.20%,降解效率提高17.52%,同时EPS增长了35.45%,蛋白质/多糖显著提升,并促进了色氨酸类氨基酸和腐殖酸的形成。以上研究结果可为处理高氨氮废水提供一种新的调控策略。