Changes in soil hydraulic conductivity, runoff, and soil loss due to irrigation with different types of saline–sodic water

Irrigation with saline–sodic water causes sodic conditions in the soil which reduces soil productivity. We evaluated the changes in a number of important indices related to soil structural stability when treated wastewater (TWW), albeit with higher loads of organic matter and suspended solids, was used instead of more saline–sodic irrigation water, under different degrees of aggregate slaking. We studied soil saturated hydraulic conductivity (HC) using disturbed samples packed in columns, and soil infiltration rate, runoff and erosion under simulated rainfall. Aggregate slaking was manipulated by wetting the samples prior to all tests at either a slow (1–2 mm h^− 1) or a fast (50 mm h^− 1) rate. Samples of a calcareous silty clay (Typic Calciorthids) from the Bet She'an Valley, Israel, were taken from plots irrigated for three years with either TWW, saline–sodic Jordan River water (JRW), or moderately saline–sodic spring water (SPW), and also from a non-cultivated area (control). With little or no aggregate slaking (use of slow wetting), higher HC values and lower amounts of total runoff and soil loss were measured compared to when more severe aggregate slaking was induced (use of fast wetting). The HC values for the TWW treatment were similar to, or lower than, those for the control and significantly higher than those for the JRW treatment. For the runoff and soil loss data, differences among the water quality treatments were, generally, more pronounced when aggregate slaking was substantially reduced, and were related to soil sodicity. Under the latter condition, runoff and soil loss from the TWW treatment were comparable with those from the control and significantly lower than those from the JRW treatment. Our results suggested that replacing saline–sodic irrigation water with TWW could have favorable effects on soil structural stability, especially under conditions where aggregate slaking can be reduced (e.g., in regions with low to moderate rain intensities; and/or use of low intensity irrigation systems).     

长期重金属胁迫下的土壤微生物特征: 沈阳张士污灌区的案例研究

Soil samples were collected from Zhangshi Wastewater Irrigation Area in the suburb of Shenyang City, China, an area with a 30-year irrigation history with heavy metal-containing wastewater. The chemical properties and microbial characteristics of the soils were examined to evaluate the present situation of heavy metal pollution and to assess the soil microbial characteristics under long-term heavy metal stress. In light of the National Environmental Quality Standards of China, the soil in the test area was heavily polluted by Cd and to a lesser degree by Zn and Cu, even though wastewater irrigation ceased in 1993. Soil metabolic quotient （qCO2） had a significant positive correlation, while soil microbial quotient （qM） had a negative correlation with content of soil heavy metals. Soil microbial biomass carbon （MBC） had significantly negative correlation with Cd, but soil substrate~induced respiration （SIR）, dehydrogenase activity （DHA）, cellulase activity, and culturable microbial populations had no persistent correlations with soil heavy metal content. Soil nutrients, except for phosphorous, showed positive effects on soil microbial characteristics, which to a certain degree obscured the adverse effects of soil heavy metals. Soil Cd contributed more to the soil microbial characteristics, but qM and qCO2 were more sensitive and showed persistent responses to heavy metals stress. It could be concluded that qM and qCO2 can be used as bioindicators of heavy metal pollution in soils.     

基于复合垂直流人工湿地的循环水养殖系统净化养殖效能与参数优化

该文对基于复合垂直流人工湿地(IVCW)的循环水养殖系统的净化效率、养殖效果和系统优化设计进行了研究.结果表明,在420 mm/d的水力负荷下,湿地可有效地去除循环水中的总悬浮物(去除率85%)、CODCr(去除率50%)、BOD5(去除率44%)、总氨氮(去除率53%)、亚硝酸盐(去除率83%)和硝酸盐(去除率54%),能够满足养殖用水的要求,整个试验期间系统实现了零污水排放.经过5个月的养殖,成功地将斑点叉尾鲴(Ictalurus punctatus)鱼苗(1.8 cm,0.08g)培育成鱼种(15.9 cm,33.9 g),成活率达到92.6%.在养殖容量、病害控制、成活率以及鱼体生长速度等方面均优于常规池塘养殖模式.建立了一个预测湿地与养殖池塘面积配比的数学模型,为实际应用和优化设计提供依据.     

复合厌氧折流板反应器-廊道式人工湿地系统运行效果

该文采用复合厌氧折流板反应器-廊道式人工湿地(Combined Anaerobic Baffled Reactor and Corridor ConstructedWetland,简称CABR-CCW)系统进行生活污水处理试验,系统分析了CABR-CCW系统的COD去除效果、脱氮除磷效果及水生植物在人工湿地系统中的作用.监测了2006年4月到2007年1月期间复合系统的运行效果,结果显示:CABR-CCW系统稳定运行后,污水日处理量为5m3,HRT约为50h,夏秋季CODCr平均去除率为78.9%,NH3-N平均去除率为89.29%;在不改变日处理量的情况下,冬季CODCr,平均去除率约56.6%,NH3-N去除率下降幅度较大,但保持在47%以上.由于CCW采用了煤渣、页岩等高吸附磷的基质,磷去除率始终保持在83.6%以上,夏秋季由于CCW水生植物吸收,去除率高达92.3%,表明磷的去除主要依靠CCW基质的吸附,而且基质吸附能力仍未达到饱和,但已表现出下降趋势.廊道式人工湿地水生植物的长势对NH3-N的去除有显著影响,对磷的去除效果影响不大.     

精馏/好氧加Fenton处理制药废水

在分析了制药废水的水质特点基础上,进行了精馏/好氧加Fenton的方法处理制药废水的实验研究,结果表明:该方法对制药废水的处理出效果显著。将精馏后的制药废水混合液COD稀释到500 mg/L,再加上COD为200 mg/L的生活污水,经过好氧和Fenton处理后的COD去除率可达80%左右;且出水COD稳定在120 mg/L左右。出水水质符合(GB-T-31962-2015)中的C级排放标准。     

Effect of Water Quality on Heavy Metal Redistribution and Mobility in Polluted Agricultural Soils in a Semi-Arid Region

Mornag Plain is a coastal area of the Mediterranean basin, which has undergone an agricultural industrial boom. The aim of this study was to investigate the different water qualities used for irrigation on heavy metal mobility in these polluted agricultural soils. The geo-accumulation indices for heavy metals (Ni, Cr, Pb, Cd, Cu, and Zn) revealed that industrial activities and used treated wastewater (TWW) contributed to soil pollution, and water irrigation always decreased this contamination. After long-term use of different water types, high perturbation of heavy metal redistribution has occurred. Groundwater use altered all heavy metal redistributions in the irrigated soil among various soil-solid and soil-solution fractions, as compared to the unirrigated soil. Slight acid water use transferred some metals from different solid phase components into water-soluble and exchangeable fractions. However, TWW use transformed some Ni, Cr, Cd, Cu, and Zn from water-soluble and exchangeable fractions to less labile fractions, particularly into organically bound fractions. Reuse of conventional water within the same soil decreased the whole soil redistribution index values, indicating tendency to return to the pattern of distribution of groundwater-irrigated soil.     

极大硬毛藻无性系对海水养殖废水中氮盐的去除效果

养殖水体中无机氮的高效去除是开展循环水养殖的重要保障条件之一。该论文研究了极大硬毛藻无性系(简称极大硬毛藻)对循环水养殖水体中无机氮盐的去除效率及特征。结果表明,当藻体密度为(10±1) g/L时,在一定浓度范围(氨氮:0～15 mg/L,亚硝酸盐氮:0～3 mg/L,硝酸盐氮:0～15 mg/L),极大硬毛藻对海水中3类无机氮盐的吸收速率随着时间变化即氮盐浓度降低而降低;其中藻类对氨氮的吸收速率变化较大,而对亚硝酸盐和硝酸盐的吸收速率相对稳定。当3种氮盐质量浓度为3 mg/L,极大硬毛藻首先选择吸收氨氮;当氨氮质量浓度降至1.5 mg/L时,藻开始吸收亚硝酸盐氮和硝酸盐氮。极大硬毛藻对人工模拟养殖废水中氨氮、亚硝酸盐氮和硝酸盐氮的15 h去除率可达到94.3%、100%、82.2%。该研究可为极大硬毛藻在循环水养殖水体净化的应用、养殖废水资源化利用和无害化处理技术的建立提供科学依据。     

Na+和K+共存对A2/O工艺脱氮除磷效果及污泥性质的影响

为了揭示多种金属离子共存的含盐废水生物处理系统污染物的去除机制和污泥特性,考察Na~+、K~+共存对A~2/O工艺污染物去除率、污泥性质和微生物群落的影响,采用高通量测序技术分析了厌氧区、缺氧区和好氧区的微生物群落结构,结合脱氮除磷效果和污泥性质的变化,探讨不同Na~+/K~+摩尔比下A~2/O工艺优势种群的演替规律,以期从微生物角度明确Na~+、K~+共存对含盐废水污染物去除率的影响。结果表明:当进水Na~+/K~+摩尔比分别为2、1和0.5时,A~2/O工艺的COD去除率分别为80%、84%和86%,TN去除率分别为73%、77%和80%,K~+浓度的提高缓解了Na~+对COD和TN去除率的抑制作用;厌氧区释磷率分别为70%、73%和74%,缺氧区吸磷率分别为53%、55%和58%,好氧区吸磷率分别为70%、72%和75%。随着进水Na~+/K~+摩尔比的降低,厌氧区、缺氧区和好氧区微生物群落的丰富度和多样性降低,微生物群落差异显著,变形菌门的相对丰度均升高约30%,拟杆菌门和绿弯菌门相对丰度逐渐降低。陶氏菌属和固氮弧菌属作为优势菌属,其相对丰度逐渐增大,有利于氮磷污染物的去除。通过增加K~+的浓度有利于提高氮、磷去除率,增强污泥的生物絮凝性和反硝化聚磷菌的活性。     

Soil organic carbon balance and nutrients (NPK) availability under treated wastewater irrigation for bioenergy sorghum production in an arid ecosystem

This column study evaluated the effects of irrigation with two water qualities (WW and FW) to produce bioenergy sorghum on SOC balance, nutrients availability and salt constituents in two soils (TX and NM) amended with gypsum & elemental sulfur (S) and un-amended. Study results indicated that SOC concentration was higher in freshwater irrigated columns (7.41 g kg^?1) than wastewater irrigated soils (7.32 g kg^?1) across growth year-soil type-amendments-depth. Soils amended with gypsum and sulfur registered significantly higher value of 7.52 and 7.41 g kg^?1 compared to 7.30 and 7.23 g kg^?1 in non-amended soils under fresh and wastewater irrigation, respectively. Lower SOC in WW irrigated columns could be due to the combined effects of increased salinity and priming effects. Although SOC content initially increased in gypsum and S amended soils to about 10g kg^?1, at the end of the study SOC in all treatments decreased to levels significantly below the pre-study. WW irrigation added 2.00, 1.10 and 4.40 times the N, P and K added by fertilizers and was able to meet 65%, 87%, and 210% of bioenergy sorghum uptake of respective nutrients. Sulfates and chlorides of sodium and calcium were dominant salts, which significantly affected SOC and nutrients.

Abbreviations: FW: freshwater; WW: treated wastewater; G + S: gypsum and elemental sulfur; NA: no amendment, TX: Texas soil and NM: New Mexico soil     

休耕田对水产养殖废水抗生素去除及风险评估

根据水产养殖废水集中于冬季排放和休耕田需在冬季引水调质的现实需求,提出将水产养殖废水回用休耕田的技术方案,并对废水中典型抗生素磺胺甲恶唑（SMX）在休耕田中的降解途径和效果进行研究,同时对水产养殖废水回用示范区休耕田进行健康风险分析。结果表明：土壤微生物降解是去除废水中SMX的主要途径,去除贡献率为65%~78%,土壤固定和植物吸收对SMX的去除贡献较低。在微生物群落属水平上检测到Arthrobacter （节杆菌属）、Sphingomonas （鞘氨醇单胞菌属）和Bacillus （芽孢杆菌属） 3类降解SMX的优势菌属。TN、NO₃^--N、TP和COD_Cr的去除效果均随SMX浓度升高而降低。在消纳水产养殖废水的休耕田中,残留的抗生素对人体健康和土壤生态系统的风险商值小于0.01,其潜在风险可忽略不计。