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101.
102.
利用耗氧速率判断好氧堆肥腐熟度的探讨 总被引:14,自引:0,他引:14
在试验的基础上分析了利用耗氧速率判断堆肥腐熟度的可行性 .试验中堆肥高温阶段持续 6d以上 ,达到国家《粪便无害化卫生标准 (GB795 9 87)》的要求 .堆肥过程中铵态氮含量下降、硝态氮含量上升 ,1 1d后 ,堆肥DOC含量为 0 5 %左右 ,种子相对发芽率达到 80 %以上 ,表明堆肥达到腐熟 .升温阶段前期 ,耗氧速率呈迅速增加的趋势 ;升温阶段后期和高温阶段前期 ,耗氧速率维持相对稳定 ,高温阶段中期、末期耗氧速率开始下降 .相对发芽率验证表明 ,在堆肥高温阶段末期 ,耗氧速率下降到 1 0 0 μL·L-1 ·s-1 以下 ,此指标可以作为堆肥腐熟的标志 .以耗氧速率代替传统的测量堆肥的理化、生物指标来判断堆肥腐熟度不需要采样、分析等复杂手续 ,将以往的需要几天才能获得腐熟状况变为实时、在线监测 ,对堆肥技术的实际推广具有重要意义 相似文献
103.
广州地区雨水化学组成与雨水酸度主控因子研究 总被引:22,自引:3,他引:22
采集了广州地区2003-10~2004-09的雨水样品,通过对雨水样品的pH值、主要阴阳离子组成和可溶性有机碳(DOC)的测定,分析了广州地区酸雨的现状以及影响雨水酸度的主要因素等.结果表明,在观测期间,广州地区酸雨频率高达85%;雨水的主要离子组成为NH4+、SO42-、NO3-、Ca2+、Cl-和Na+,而DOC约占总化学组成的24.0%;雨水酸度的主要控制离子还是SO42-,但NO3-对雨水酸度的影响越来越大;同时,水溶性有机酸对雨水酸度的贡献也很明显.另外,来自扬尘中高浓度的碱性含钙化合物也对雨水酸度有明显的中和作用. 相似文献
104.
测定了伊春河流域河水、井水、坡面漫流、土壤淋溶液等样品中的水溶性有机物含量,据此结果建立了河水溶解态有机物来源的概念模型。并根据不同流速条件下土壤水溶性有机物淋溶模拟实验的结果,探讨了水溶性有机物从山地土壤中淋溶的动力学过程。研究发现,吸着在土壤有机-矿质复合体表面的水溶性有机物的淋溶包括三个连续的动力学过程:即从复合体表面进入土壤毛管水的解吸作用,自土壤团粒结构内部转移到土壤重力水中的扩散和相迁移过程,以及被流动相携带淋溶的对流过程。这一物理模型可以表述为包括三个加和项的简单表达式,模型中的迁移速率常数与流动相线速度的某一方次成正比。 相似文献
105.
DOC+CDPF配方对柴油公交车颗粒物排放特性影响 总被引:1,自引:0,他引:1
为研究不同DOC+CDPF(催化型连续再生颗粒捕集器)配方对公交车颗粒物排放特性的影响,以一辆满足国Ⅲ排放的柴油公交车为试验样车,在重型底盘测功机上分别进行了加装3种不同DOC+CDPF的柴油机在中国典型城市公交车循环(CCBC)中的排放特性试验,分析了不同贵金属负载量对柴油机颗粒物排放特性的影响.结果表明:在相同贵金属配比情况下,当DOC+CDPF催化剂配方中贵金属负载量较高时,颗粒物浓度降幅较大.3种方案的颗粒物质量浓度综合减排率分别为99.3%、98.8%、96.4%,平均降幅达到98.2%;当使用DOC+CDPF后,柴油机颗粒物粒径分布由双峰对数分布变为三峰对数分布,但不同催化剂配方下对应的粒径最大峰值点会偏移;采用DOC+CDPF装置后,发动机排放背压略有增加.且当贵金属负载量越高时,装置压降增量越少,被动再生性能越优异. 相似文献
106.
不同施肥措施对土壤活性有机碳的影响 总被引:29,自引:8,他引:29
采用田间试验,研究了不同施肥措施下,华北冬小麦-夏玉米轮作体系中潮土土壤活性有机碳含量及组分的变化特征.结果表明,施肥显著增加土壤水溶性有机碳和易氧化有机碳含量,与不施肥相比,增加幅度分别为24.92~38.63 mg·kg-1和0.94~0.58 g·kg-1,其中单施有机肥对土壤水溶性有机碳含量增加作用大于配施化肥和化肥单施,单施有机肥或与化肥配施对土壤易氧化有机碳的提升效果优于单施化肥.有机肥或化肥单施对土壤微生物量碳没有显著促进作用,而有机肥与化肥配施土壤微生物量碳含量分别增加36.06%和20.69%;土壤易氧化有机碳、水溶性有机碳和微生物量碳占总有机碳的比例变化范围分别为8.41%~14.83%、0.47%~0.70%和0.89%~1.20%,施肥显著提高了土壤水溶性有机碳和易氧化有机碳比例,不同施肥措施对水溶性有机碳的提升效应没有显著差异.有机肥与化肥配施对易氧化有机碳的比例提升作用大于有机肥或化肥单施,同时显著增加土壤微生物量碳比例,但有机肥或化肥单施对土壤微生物量碳比例没有显著作用.可见,在试验地条件下,有机肥与化肥的适当配施对于增加土壤活性有机碳含量和有效调控其关键组分具有重要作用. 相似文献
107.
108.
利用CDOM吸收系数估算太湖水体表层DOC浓度 总被引:8,自引:6,他引:8
溶解有机碳(DOC)是水体中最大的有机碳库,在水体碳循环中起着重要作用.有色溶解有机物(CDOM)是DOC的重要组成部分,其吸光作用改变着水下光场结构,是水色遥感监测的重要因子之一,建立两者的联系为利用遥感技术估算湖泊水体表层DOC浓度提供有效的技术方法.基于2010年5月、2011年1月、2011年3月和2011年5月的太湖4期实验数据(183个采样点),利用CDOM特征波长吸收系数[ag(250)和ag(365)]建立多元线性模型估算太湖水体DOC浓度,同时利用2011年8月29日~9月2日的数据(n=27)对模型进行验证评价,并构建了湖泊水体DOC浓度的遥感反演模式.结果表明,该模型能够有效估算太湖水体的DOC浓度;2011年1月DOC和CDOM的源和汇有较大差异,估算效果较差;其他3期数据的模型估算效果显著(R2=0.64,RMSE=14.31%,n=164),并在201108期数据中得到了验证(R2=0.67,RMSE=10.58%,n=27).模型形式虽具有一定的通用性,但系数在不同的水域中有所差异,模型系数的区域化成为下一步研究的重点. 相似文献
109.
中国对虾养殖系统中溶解有机碳和胶体有机碳的动态变化 总被引:1,自引:2,他引:1
运用切向超滤技术对中国对虾培养系统进行了研究。结果表明,在对虾周日观测中DOC和COC低值出现在下午,而高值则在夜间出现,一日之内波动剧烈,胶体有机碳的活性较大;在周日观测中COC/DOC%与DOC和COC有相近的变化趋势,但增大的趋势更为明显;在连续7d的动态观测中,DOC和COC与时间呈显著的线性正相关,系统内DOC和COC在培养过程中的自然积聚与换入海水物理混合的共同作用使得体系内的DOC和COC的浓度随着时间而缓慢的增加;在整个培养过程中,COC与DOC具有很好的线性正相关,其斜率为0 43,COC在对虾培养系统中占总DOC的比例远高于天然海水。 相似文献
110.
Katsoyiannis A Samara C 《Environmental science and pollution research international》2007,14(5):284-292
Goal, Scope and Background Dissolved organic carbon (DOC) constitutes a parameter of organic pollution for waters and wastewaters, which is not so often
studied, and it is not yet regulated by directives. The term ‘DOC’ is used for the fraction of organics that pass through
a 0.45 μm pores’ size membrane. The type of wastewater plays an important role in the quality of DOC and it has been shown
that DOC may contain aquatic humic substances, hydrophobic bases, hydrophobic neutrals, hydrophilic acids, hydrophilic bases
and hydrophilic neutrals. The quality of the DOC is expected to affect its fate in a wastewater treatment plant (WWTP), since
a considerable fraction of DOC is not biodegradable, and it may be released in the aquatic environment together with the treated
effluent.
In the present study, the occurrence of DOC during the wastewater treatment process is investigated and its removal rates
during primary, secondary and overall treatment are being estimated. Furthermore, a correlation is being attempted between
DOC and the concentrations of selected Persistent Organic Pollutants (POPs) and Heavy Metals (HMs) in the dissolved phase
of wastewaters, to examine whether there are common sources for these pollution parameters in WWTPs. Also, DOC is being correlated
with the partition coefficients of the above-mentioned pollutants in wastewater, in order to examine the effect of ‘solubility
enhancement’ in WWTPs and to evaluate the result of this phenomenon in the efficiency of a WWTP to remove organic pollutants.
Methods For the purposes of this study, 24-h composite wastewater samples were collected from the influent (raw wastewater, RW), the
effluent of primary sedimentation tank (primary sedimentation effluent, PSE) and the effluent of secondary sedimentation tank
(secondary sedimentation effluent, SSE). Samples were analyzed for the presence of 26 POPs (7 PCBs and 19 organochlorine pesticides),
8 HMs and DOC.
Results and Discussion Mean concentrations of DOC in RW and PSE were at similar levels (∼ 70 mg l−1), suggesting that primary treatment has a minor effect on the DOC content of wastewater. DOC concentrations in SSE were significantly
lower (∼ 19 mg l−1) as a result of the degradation of organic compounds in the biological reactor. Calculated removals of DOC were 0.8% in the
primary treatment, 63% in the secondary treatment, and 69% in the overall treatment, exhibiting large differences from other
organic pollution parameters, such as BOD and COD. The overall DOC removal was found to be independent from the DOC concentration
in raw wastewater. Poor correlation was also observed between the DOC content and the concentrations of wastewater contaminants,
such as persistent organic pollutants (POPs) and heavy metals (HMs), probably suggesting that their occurrence in WWTPs is
due to different sources. A good negative linear relationship was revealed between DOC concentrations and the logarithms of
the distribution coefficients (K
d) of various POPs and HMs between the solid and the liquid phases of wastewater. This relationship suggests that DOC facilitates
hydrophobic pollutants to remain in the dissolved phase thus causing lower removal percentages during the treatment process.
Conclusion DOC was measured at three stages of a municipal WWTP that receives mainly domestic wastewater and urban runoff. DOC concentrations
in untreated and primarily treated wastewater were almost equal, and only after the secondary sedimentation there was a decrease.
Concentrations and removal rates of DOC were in the same levels as in other WWTPs that receive municipal wastewater. The origin
of DOC was found to be different to the one of POPs and of HMs, as no correlation was observed between the concentrations
of DOC and the concentrations of these pollutants. On the contrary, DOC was found to have significant negative correlation
with the K
d of all pollutants examined, suggesting that it plays an important role in the partitioning of those pollutants between the
dissolved and the sorbed phase of wastewaters. This effect of DOC on partitioning can affect the ability of WWTPs to remove
toxic pollutants, and that way it facilitates the discharge of those chemicals in the aquatic ecosystems together with the
treated effluent.
Recommendation By the results of this work it is shown that the presence of DOC in wastewaters can significantly affect the partition of
hazardous pollutants between the dissolved and the sorbed phase. It is therefore of importance that this parameter is controlled
more in wastewaters, since it can cause a decrease in the efficiency of WWTPs to remove quantitatively persistent pollutants. 相似文献