山丘区水环境容量计算及限制排污总量分析——以临海市“五水共治”规划为例

为改善山丘区水环境,以典型山丘区城市临海市为研究对象,基于对临海市水环境现状、水环境功能及水污染负荷的充分调查,建立河网水量水质数学模型,计算了河网水环境容量,并提出了污染物排放总量控制和削减方案。结果表明:临海市河网的水环境容量COD为15 904.3 t/a,NH3-N为1585.2 t/a,水质超标率分别为COD 15.61%,NH3-N 16.67%。规划年工程实施后预计新增水环境容量COD 1 137.7 t/a,NH3-N 114 t/a,削减污染物入河量COD 10 610.6 t/a,NH3-N 1 082 t/a,水环境质量得到较大提升。     

基于京杭运河五牧断面水质达标的水环境容量计算研究

为保证京杭运河五牧断面的水质达标率及水体环境健康,依据《江苏省地表水(环境)功能区划》,综合考虑水文、水体污染来源等因素,对整治范围内入运河的污染源进行概化,通过建立一维水量水质数学模型确定模型参数,计算五牧断面水质达标时各概化排口的允许排污量,进而得到该研究区域的水环境容量,与现状污染物入河量对比,确定污染物削减量,为改善京杭运河水环境质量提供依据。结果表明:确保京杭运河五牧断面水质达标情况下,研究区域近期COD、氨氮、总磷水环境容量分别为47 216t/a、5 376.1 t/a、508.1 t/a,远期COD、氨氮、总磷水环境容量分别为28 977.3 t/a、2319.1 t/a、301.1 t/a。污染物削减率与水质超标率对比二者差距在30%以内,说明水环境容量计算结果基本合理。     

Nitrogen and phosphorus changes and optimal drainage time of flooded paddy field based on environmental factors

While many controlled irrigation and drainage techniques have been adopted in China, the environmental effects of these techniques require further investigation. This study was conducted to examine the changes of nitrogen and phosphorus of a flooded paddy water system after fertilizer application and at each growth stage so as to obtain the optimal drainage time at each growth stage. Four treatments with different water level management methods at each growth stage were conducted under the condition of ten-day continuous flooding. Results show that the ammonia nitrogen (NH⁺₄-N ) concentration reached the peak value once the fertilizer was applied, and then decreased to a relatively low level seven to ten days later, and that the nitrate nitrogen (NO^-₃-N) concentration gradually rose to its peak value, which appeared later in subsurface water than in surface water. Continuous flooding could effectively reduce the concentrations of NH⁺₄-N, NO^-₃-N , and total phosphorus (TP) in surface water. However, the paddy water disturbance, in the process of soil surface adsorption and nitrification, caused NH⁺₄-N to be released and increased the concentrations of NH⁺₄-N and NO^-₃-N in surface water. A multi-objective controlled drainage model based on environmental factors was established in order to obtain the optimal drainage time at each growth stage and better guide the drainage practices of farmers. The optimal times for surface drainage are the fourth, sixth, fifth, and sixth days after flooding at the tillering, jointing-booting, heading-flowering, and milking stages, respectively.     

吴江市水功能区纳污能力及限制排污总量研究

依据《江苏省水功能区划》,结合吴江市水资源质量及污染现状,采用一维非稳态模型确定水质参数,计算吴江市水功能区纳污能力,核定限排总量,与吴江市现状污染物入河量对比,确定污染物削减量,为吴江市水污染防治与污染减排工作提供方法和依据。结果表明:吴江市水功能区水域纳污能力CODCr和氨氮分别为17 344和1 672 t/a,为入河量的56%和57%,CODCr和氨氮的平均削减率分别为54%和56%,该结果与污染物入河量、水质超标率结果基本吻合,说明纳污能力与限排总量计算结果合理。     

落蓬湾断面水质达标及胥河水环境容量研究

落蓬湾断面目前水质不能稳定达标。为进一步提高国家考核断面水质达标率,持续改善水环境质量,进而开展落蓬湾断面水质达标及胥河水环境容量计算研究。根据现状水文、水质和污染源资料,分析落蓬湾断面水质超标原因。采用控制断面达标法计算得到入胥河的最大允许排污量。结果表明:胥河COD、氨氮、总磷的近期水环境容量分别为3011.8、195.0、99.2 t/a,远期水环境容量分别为1738.7、135.9、70.0 t/a。基于胥河水环境容量计算结果,结合研究区域内入胥河的污染物量,确定研究区域各类污染物的削减比例,为胥河的水环境整治提供理论支撑。     

动态纳污能力计算方法与应用研究

通过环境水槽实验获取了COD和NH3-N衰减系数与流速效应之间的定量关系式,建立了反应污染物衰减与流速动态变化的二维水流水质数学模型。以广东省飞来峡水利枢纽库区为例,利用二维水流水质数学模型和常规的完全混合模型对库区COD和NH3-N纳污能力进行了计算。结果表明:前者计算的纳污能力大于后者,其计算出的主流区纳污能力为库湾区的8.4倍左右。分析认为二维水流水质数学模型计算结果更符合实际。     

基于自由搜索的灌区优化配水模型研究

在求解优化配水问题时,遗传算法和粒子群算法是经常被采用的优化算法,然而在优化过程中可能出现早熟,从而会影响到配水模型的有效性。为此,本文引入一种新的基于动物群体的优化算法——自由搜索(FreeSearch)算法,并以实现单位灌溉水量的净收益最大为目标构建了灌区优化配水模型,设自由搜索中动物探查行走时的位置分量为模型寻优参数,应用自由搜索算法对模型进行优化求解。实例应用结果表明:与加速遗传算法和标准粒子群算法求解优化配水模型的结果相比,本文建立优化配水模型能为灌区提供更合理的优化配水方案,可使整个灌区及单位灌溉水量的净收益都获得显著增长。     

渭河陕西段河水水质COD、NH3-N变化特征分析

渭河是黄河的一级支流,是重要的地表水体。随着近年来国民经济的飞速发展,工业农业用水量不断上升,排入渭河的污染物质逐年增加,致使渭河的水质污染不断加剧,已基本丧失了其原有功能。分析渭河水质变化特征对于防治渭河水污染具有重要的指导作用。通过对渭河干流的19个监测断面以及渭河(陕西段)断面的COD和NH3-N监测数据进行统计分析。结果表明:虽然渭河的水质总体恶化趋势得到有效的遏制,但渭河干流仍有1/2的监测断面没有达到水环境功能的要求,2007-2011年虽然渭河一些断面的水质仍为劣Ⅴ类,但COD和氨氮的浓度呈逐年降低的趋势。     

Nonpoint N Runoff from Agricultural Watersheds into the Great Lakes

Eleven agricultural watersheds were continuously monitored for discharge and intensively sampled for runoff N, 1975-77, as part of the IJC Pollution from Land Use Activities Reference Group (PLUARG), Task Group C (Canadian). The watersheds, located in southern Ontario, were sampled between 30 to more than 500 times for NH₄-N, N0₃+N0₂-N, and total Kjeldahl N (TKN).The predominant chemical form of runoff N was N0₃-N with flow weighted concentration means on sampled days ranging from 0.57 to 5.62 mg/L. In contrast, TKN means ranged from 0.64 mg/L to 2.37 mg/L while average soluble NH₄-N concentrations varied from 0.03 mg/L to 0.60 mg/L. High runoff N0₃-N concentrations occurred from watersheds with extensive areas of tile drainage, row crops (especially com), and high kg/ha fertilizer N application rates. Elevated stream TKN concentrations were associated with watersheds with more impermeable soils.Stream N0₃-N loadings ranged from 2.1 ± 0.2 to 39.0 ± 7.6 kg N0₃-N/watershed ha. Significant N fertility losses in excess of 30 kg N0₃-N ha occurred from some watersheds, while other watersheds with extensive areas of hay and pasture and unimproved land gained more N0₃-N in precipitation than was lost as runoff. TKN loads averaged 32% and 25% of total N runoff for the 11 watersheds in 1975 and 1976 respectively. Efforts to reduce Ontario watershed N runoff should concentrate first on soluble N and therefore on improved efficiency of N fertilizer use on the extensive areas of tile drained corn in the lower Great Lakes basin. The effectiveness of standard soil erosion control methods, including grassed waterways and contour planting, should be investigated for reduction of TKN runoff.     

土壤过滤系统处理农村生活污水过程中污染物的变化规律

采用一种土壤过滤系统处理农村生活污水,分析了该工艺处理过程中CODCr、BOD5、NH3-N、全氮(TN)和全磷(TP)的时空变化规律。实验结果表明:去除季节效果由高到低依次为:夏季>秋季>春季>冬季。土壤过滤系统对CODCr、BOD5、NH3-N、TN和TP的最高去除率分别达到87.3%、88.2%、75.9%、59.3%和74.1%;在土壤过滤系统内,沿着水流的水平方向,各物质去除率逐渐增大。采用该技术处理后,排水中TN、TP的浓度较高,用于灌溉可减少化肥使用量和节省淡水资源。     

基于龙王庙断面水质达标的城南河流域水环境容量

为保证南京市浦口区城南河龙王庙断面水质稳定达标,综合考虑水文、水质和污染源现状,对研究区域入城南河的污染源进行排污口概化,构建水环境数学模型,计算得到基于龙王庙断面水质达标的城南河水环境容量,以此与现状入河的污染物量比较,确定污染物的削减比例。结果表明:在保证龙王庙断面水质达标的情况下,城南河COD、NH+4-N和TP的水环境容量分别为2 183 t/a、201 t/a和154 t/a,污染物削减率与水质超标率的差距在20%以内。     

全国重要江河湖泊水功能区限制排污总量控制方案

对全国4 493个重要江河湖泊水功能区纳污能力进行了核定,结合水功能区水质状况、纳污能力和现状污染物入河量,提出了限制排污总量确定的原则,制定了水平年2020年和2030年的限制排污总量控制成果:2020年,COD 585.20万t/a,氨氮52.57万t/a;2030年,COD 542.97万t/a,氨氮46.54万t/a。对各省级行政区限制排污总量成果进行分析,结果表明,大多数省级行政区各水平年限制排污总量呈逐步递减趋势,与规划水平年水功能区水质达标率逐步增加的目标要求总体协调。根据限制排污总量方案,提出了加强水功能区限制排污总量管理的对策、措施和建议:加快开展水资源监控能力建设;切实加强水功能区监督管理;严格控制入河湖排污总量;不断加大水资源保护投入力度;完善政策法规和管理制度体系;强化宣传教育和公众参与。     

控灌中蓄及减量施肥对稻田氮素动态的影响

为寻求高效生态的水-肥管理模式以减轻稻田施肥所引起的面源污染,在浙江省余姚试验区采用对比试验观测田面水与各土层土壤水中氮素形态及其质量浓度,对不同水肥管理模式下稻田氮素的变化规律进行分析。结果表明:施基肥7 d后减量施肥,田面水的NH+4-N质量浓度均值为常规施肥的46.14%,NO-3-N质量浓度均值为常规施肥的83.62%;控灌中蓄节水灌溉模式与减量施肥耦合能延长田间水的滞蓄时间,使稻田氮素肥料快速入渗并较多地保留在作物耕层,提高氮肥的有效利用率,降低田面排水的氮素浓度,减少氮素的深层渗漏;施肥后4 d内田面水的氮素浓度较高,应控制排水以避免氮肥流失,减轻稻田氮肥施用所引起的农业面源污染。     

沉积物-水界面中可交换态氮对不同菹草密度的响应

为了认清沉水植物对富营养化浅水湖泊沉积物-水界面可可交换态氮的影响,通过模拟试验,利用连续流动注射分析仪测定了NO-3-N、NH3-N等指标,并结合其他环境指标,研究了沉积物-水界面中TN、NO-3-N、NH3-N对不同菹草量(0 g、150 g、300 g)的响应。结果表明,菹草的存在增加了间隙水氧化还原电位(Eh),降低了p H,且菹草量越大,间隙水中Eh、p H值变化越明显;利用单因素方差分析,得出300 g菹草组与对照组的间隙水TN质量浓度有显著差异(P0.05);菹草量越大,间隙水中TN、NO-3-N和NH3-N以及表层沉积物中固定态铵、有机氮、NH3-N和NO-3-N的去除效果越好。     

牛栏江—滇池补水工程对滇池外海的水环境改善效果研究

利用牛栏江-滇池补水工程运行前后的水质实测资料,对滇池外海的水环境改善效果进行研究。选取TP、TN、NH_3-N、COD_(Mn)、Chl-a、SD等主要水环境指标,从指标浓度变化、水质类别变化、指标向好率变化和极大值变化等方面分析牛栏江-滇池补水工程对滇池外海的水环境改善效果。结果表明,牛栏江-滇池补水工程运行后,滇池外海各监测站点的TP、TN、NH_3-N、COD_(Mn)、Chl-a、SD及营养状态指数均优于调水前,富营养化水平明显好转,水环境改善成效显著。     

Simulation of Water Quality under Different Reservoir Regulation Scenarios in the Tidal River

Reservoir regulation is one of the effective ways to improve water quality. However, when water quality requirement is considered, reservoir operation is complicated due to tidal regimes in the tidal rivers. The study was carried out in the tidal river reach between Dongjiang Hydro-Project and Shilong in Dongjiang River. To evaluate the effect of reservoir regulation on water quality, a two-dimensional hydrodynamic model combined with water quality has been developed. Under the scenarios of differrent flood discharge from the Shima River and different release discharge of Dongjiang Hydro-Project, water quality is simulated using the two-dimensional model. NH₃-N and COD concentrations are taken as the major indicators for water quality. Results indicate that (1) water quality is related to the tidal fluctuation, NH₃-N and COD concentrations increase at flood tide and decrease at ebb tide; (2) There is no obvious over-limit of COD concentration, NH₃-N concentration is found as the main pollution impacts water quality at water intake; (3) flood discharge from Shima River flows back to the upper reach of water intake during higher high tidal period, NH₃-N concentration non-compliance occurs, flood tide is the main factor which impacts water quality; (4) reservoir regulation of Dongjiang Hydro-Project causes a significant improvement on water quality, release discharge of Dongjiang Hydro-Project is determined to insure the water supply safety, which keeps tidal-induced backwater always flowing to lower reach of the water intake. The study provides a hydrodynamic perspective on water quality improvement due to reservoir regulation in the tidal river.     

上海市水功能区纳污能力和分阶段限排总量研究

以COD、NH3-N为控制指标,应用一维感潮河网纳污能力模型计算上海市水功能区水域纳污能力。结果表明,上海市水功能区COD和NH3-N的纳污能力分别为79.96万t/a和7.56万t/a。以水功能区水质和污染物入河量分析评价结果为基础,制定水功能区分阶段达标目标,并从空间和时间上分解,提出每个水功能区分阶段限制排污总量控制方案。     

渭河陕西段底泥间隙水与上覆水中污染物分布特征研究

通过渭河8个断面2015年4月和9月的采样分析,探讨了表层底泥间隙水和上覆水中污染物的分布特征,并对间隙水和上覆水中的污染物浓度进行了相关性分析。结果表明:在丰水期时上覆水中TN、NO_3—N、NH_3—N及COD含量均高于平水期,其中采样点D5(泾河汇入前渭河干流处)的污染物含量很高;间隙水中TN、NH_3—N、NO_3—N变化趋势相似,丰水期TN、NH_3—N、NO_3—N含量均高于平水期含量,采样点D5、D7(泾河汇入后干流处)丰水期总磷、COD含量很高;相关性分和上覆水中TN、COD浓度在丰水期高度相关,说明间隙水中TN、TP、COD的浓度是其上覆水中TN、TP、COD浓度的决定因素。     

太湖富营养化主要指标及营养水平变化分析

分析了太湖1980-2011年富营养化水质指标的变化情况,同时利用水质富营养化评价结果,分析了2002-2011年不同湖区营养水平的变化特征。结果表明:太湖富营养化水质指标整体呈上升趋势,虽然TN和TP在1996年后开始降低,但仍处于较高水平;NH+4-N和Chl-a的最高值出现在2006年;TN和NH+4-N具有相似的月间变化特征,但是NH+4-N的极值较TN提前一个月出现;CODMn和Chl-a呈单峰的月间变化特征,而TP的月间变化呈双峰特征。西部沿岸区和五里湖的水质改善明显,梅梁湖、竺山湖和南部沿岸区水质改善不明显,东部沿岸区和东太湖水质呈恶化趋势。太湖不同湖区富营养水质出现频次的月变化特征也非常明显。     

浑河沈抚段水体污染季节性变化研究

为明确浑河沈抚段水污染特征,提升水环境治理有效性,2015年3月—2016年2月对浑河沈抚段进行水环境调查。根据丰、平、枯3个水期的pH值、电导率、COD、NH_3-N、BOD及COD_(Mn)等水质指标,运用改进的综合水质标识指数法识别出主要污染因子,并分析浑河沈抚段水质污染时空变化特征。结果表明,研究区域的pH值在一个水文年变化范围为6.42~8.06,较适宜水生生物生长;水体在枯水期的电导率最高,丰水期最低。浑河沈抚段水体受沿岸工业废水和生活污水的点源污染影响,流域枯水期和平水期各监测断面的综合水质均未达标;从上游到下游4项水质指标的综合水质指数增大,污染逐渐加重,主要污染指标为COD和NH_3-N。