Implications of de Facto Reuse on Future Regulatory Developments for Beaufort-Jasper Water & Sewer Authority in Okatie, South Carolina, USA

A significant portion of the national water supply can be attributed to de facto or unplanned potable reuse, though the extent of its contribution is difficult to estimate. Fortunately, the contribution of Water Resource Recovery Facility (WRRF) effluent to waters that supply drinking water treatment plants has been documented by some communities. In the United States (US), among the top 25 most impacted drinking water treatment plants by upstream WRRF, 16% of the influent flow to the drinking water treatment plant under average streamflow and up to 100% under low-flow conditions is WRRF effluent. Currently, the full extent of de facto reuse in the US may be much higher because of population growth. The scenario is no different for Beaufort-Jasper Water and Sewer Authority (BJWSA) in South Carolina, US, with contributions to the Savannah River originating from numerous WRRF and other upstream dischargers. South Carolina coastal utilities such as BJSWA are considering direct and indirect potable reuse options, driven by disposal limitations and challenges. Currently, South Carolina does not have a framework, guidelines, or regulations for reuse, but discussions have started among the regulated community. In addition to understanding the extent of de facto reuse, the state will need to develop standards and best practices to enable future adoption of planned potable reuse solutions to water resources challenges. Such guidance should address human health risk management and technical considerations regarding treatment in addition to other factors, including source control, storage, fail-safe operation, monitoring, non-cost factors, and public acceptance. This study conducted a mapping assessment specific to BJWSA, sampled at four locations on Savannah River, and observed that de facto reuse is approximately 4.6% to 5.9% during low-flow months and is within the range generally observed nationwide. When coupled with evidence that planned potable reuse can improve human health and environmental risks, this practice is a meaningful option in the water supply portfolio for many utilities.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

Analysis of Water Resources Supply and Demand and Security of Water Resources Development in Irrigation Regions of the Middle Reaches of the Heihe River Basin, Northwest China

Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.

Land Cover Changes and Drivers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China from 2000 to 2015

The Middle Route of the South-to-North Water Diversion Project(MR-SNWDP)in China,with construction beginning in 2003,diverts water from Danjiangkou Reservoir to North China for residential,agriculture and industrial use.The water source area of the MR-SNWDP is the region that is most sensitive to and most affected by the construction of this water diversion project.In this study,we used Landsat Thematic Mapper(TM)and HJ-1 A/B images from 2000 to 2015 by an object-based approach with a hierarchical classification method for mapping land cover in the water source area.The changes in land cover were illuminated by transfer matrixes,single dynamic degree,slope zones and fractional vegetation cover(FVC).The results indicated that the area of cropland decreased by 31%and was replaced mainly by shrub over the past 15 years,whereas forest and settlements showed continuous increases of 29.2% and 77.7%,respectively.The changes in cropland were obvious in all slope zones and decreased most remarkably(–43.8%)in the slope zone above 25°.Compared to the FVC of forest and shrub,significant improvement was exhibited in the FVC of grassland,with a growth rate of 16.6%.We concluded that local policies,including economic development,water conservation and immigration resulting from the construction of the MR-SNWDP,were the main drivers of land cover changes;notably,they stimulated the substantial and rapid expansion of settlements,doubled the wetlands and drove the transformation from cropland to settlements in immigration areas.

Diagnosing anomalous characteristics of atmospheric water cycle structure during seasonal-scale drought events:A case study in middle and lower reaches of Yangtze River

Anomalous characteristics of the atmospheric water cycle structure are highly significant to the mechanisms of seasonal-scale meteorological droughts.They also play an important role in the identification of indicative predictors of droughts.To better understand the causes of seasonal meteorological droughts in the middle and lower reaches of the Yangtze River(MLRYR),characteristics of the atmospheric water cycle structure at different drought stages were determined using standardized anomalies.The results showed that the total column water vapor(TCWV)was anomalously low during drought occurrence periods.In contrast,there were no anomalous signals at the drought persistence and recovery stages in the MLRYR.Moreover,there was no significant temporal correlation between the TCWV anomaly and seasonal-scale drought index(the 3-month standardized precipitation index(SPI_(3))).During drought events,water vapor that mainly originated from the Bay of Bengal was transported southwest of the MLRYR.Meanwhile,the anomalous signal of water vapor transport was negative at the drought appearance stage.At the drought persistence stage,the negative anomalous signal was the most significant.Water vapor flux divergence in the MLRYR showed significant positive anomalous signals during drought events,and the signal intensity shifted from an increasing to a decreasing trend at different drought stages.In addition,a significant positive correlation existed between the anomaly of water vapor flux divergence and regional SPI_(3).Overall,water vapor flux divergence is more predictive of droughts in the MLRYR.

Optimum development options and strategies for water injection development of carbonate reservoirs in the Middle East

Through the research on several carbonate reservoirs developed in the Middle East, the basic characteristics of different types of carbonate reservoirs are determined, and a set of high-efficiency water injection development options and strategies are presented. Hidden baffles and barriers exist in carbonate reservoirs in the Middle East, so the reservoirs could be divided into different separated development units based on the baffles and barriers characteristics. Flexible and diverse profile control techniques such as high angle wells and simple and applicative zonal water injection have been introduced to improve the control and development degree of reservoirs. Three principal water injection development methods suitable for different carbonate reservoirs in the Middle East are proposed, including the combination of crestal gas injection and peripheral water injection, bottom interval injection and top interval production(buoyancy underpinning), and "weak point and strong plane" area well pattern. Based on the characteristics of very low shale content, fast and far pressure transmission in the Middle East carbonate reservoirs, a large well-spacing flood pattern is recommended, and reasonable development strategies have been made such as moderate water injection rate and maintaining reasonable production pressure drawdown and voidage replacement ratio, so as to maximize the recovery of reservoirs in the none or low water cut period.

Water accounting for conjunctive groundwater and surface water irrigation sources: A case study in the middle Heihe River Basin of arid northwestern China

Oases in arid northwestern China play a significant role in the region＇s economic stability and development. Overex- ploitation of the region＇s water resources has led to serious environmental consequences. In oases, irrigated agriculture is the primary consumer of water, but water shortages resulting from dramatically growing human needs have become a bottleneck for regional sustainable development, making effective management of the limited available water critical. Effective strategies must be formulated to increase agricultural productivity while reducing its environmental impacts. To support the development of such strategies, water use patterns were analyzed during the 2007 and 2008 growing seasons, from May to early October, to identify opportunities for improving water management using the Mold- en-Sakthivadivel water-accounting method, which combines groundwater and surface water into a single domain and can provide a good estimate of the uses, depletion, and productivity of water in a water basin context. The study area lies in Linze County, Gansu Province, China. In the study area, the inflow water resources consist of irrigation, precipita- tion, and soil water, which accounted for 89.3%, 8.9%, and 1.8% of the total in 2007, and 89.3%, 4.8%, and 5.9% in 2008, respectively. The irrigation depends heavily on groundwater, which accounted for 82.1% and 83.6% of the total irrigation water in 2007 and 2008, respectively. In 2007 and 2008, deep percolation accounted for 50.1% and 47.9% of the water outflow, respectively, with corresponding depleted fractions of 0.51 and 0.55, respectively. For the irrigation district as a whole, the water productivity was only 1.37 CNY/m^3. To significantly increase crop water productivity and prevent depletion of the region＇s groundwater aquifer, it will be necessary to reduce the amount of water used for ir- rigation. Several water-saving agricultural practices are discussed and recommended.

Eco-environmental benefit assessment of China's South-North Water Transfer Scheme——the middle route project

This paper assess the eco-environmental benefits that may come from the middle route project of China's South-North Water Transfer Scheme(SNWT) with principles and methods of eco-economics and planning reports of SNWT's middle route project. Some benefits were calculated in monetary units. To make sure that the results can be comparable with normal monetary indices, concrete assessment objects and the parameters are prudently selected according to the major characteristics of the project and its water import region. Primary assessment revealed that in different project construction stages, the benefit could be more than 13 07 billion RMB Yuan in 2010 and 19 79 billion RMB Yuan in 2030, respectively. The monetary value tends to increase with social-economic development. To realize these potential benefits, however, calls for more endeavors.

Relationship between sand-dust weather and water dynamics of desert areas in the middle reaches of Heihe River

Sand-dust weather has become an international social-environmental issue of common concern, and constitutes a serious threat to human lives and economic development. In order to explore the responses of natural desert sand and dust to the dynamics of water in desertification, we extracted long-term monitoring data related to precipitation, soil water, groundwater, and sand-dust weather. These data originated from the test stations for desertification control in desert areas of the middle reaches of the Heihe River. We used an algorithm of characteristic parameters, correlations, and multiple regression analysis to establish a regression model for the duration of sand-dust weather. The response char-acteristics of the natural desert sand and dust and changes of the water inter-annual and annual variance were also examined. Our results showed： （1） From 2006 to 2014 the frequency, duration, and volatility trends of sand-dust weather obviously increased, but the change amplitudes of precipitation, soil water, and groundwater level grew smaller. （2） In the vegetative growth seasons from March to November, the annual variance rates of the soil moisture content in each of four studied layers of soil samples were similar, and the changes in the frequency and duration of sand-dust weather were similar. （3） Our new regression equation for the duration of sand-dust weather passed the R test, F test, and t test. By this regression model we could predict the duration of sand-dust weather with an accuracy of 42.9%. This study can thus provide technological support and reference data for water resource management and re-search regarding sand-dust weather mechanisms.

Impact of Water-Sediment Regulation on Variations of Amino Acids in the Middle-Lower Yellow River, China

In order to examine the impacts of water-sediment regulation on regional carbon cycling,we collected water,particulate and sediment samples from the middle-lower Yellow River in late June and early July,2015 and analyzed their specific amino acids(AA),DOC,POC,and bacteria abundance.Summarized by 14 specific AA,the total hydrolysable AA(THAA),particulate AA(PAA),and sediment AA(SAA)varied in ranges of 2.29-9.05μmol L^-1,5.22-22.96μmol L^-1,and 81.7-137.19μg g^-1 dry weight.After the regulation,dissolved free AA(DFAA)decreased by 29%while DCAA increased by 72%.These variations suggested that DFAA were further degraded,while DCAA molecules were further activated.Meanwhile,PAA increased almost 4 times as many as those before regulation,and SAA increased as well.After regulation,the amounts of bioactive amino acids(Asp,Glu and Gly)increased in THAA but decreased in PAA,with little changes in SAA.The ratios of Asp/Gly in different phases increased after regulation,indicating the AA contributions were promoted by calcareous organisms rather than by siliceous organisms.Multiple correlation analysis showed that PAA was primary representatives of AA and organic carbon,followed by DCAA and POC.Moreover,bacterial reproduction played a key role in shaping the AA compositions and properties,followed by the redox condition and acid-base balance.The results of this study provided a clear evidence for the effects of water-sediment regulation on regional biogeochemistry of organic carbon in the middle-lower Yellow River.

Water Dynamics of the Sefrou Watershed, Northern Tabular Middle Atlas, Morocco

The Sefrou watershed, located in the northern part of the Tabular Middle Atlas, is the primary watershed in the Sebou region. Due to increasing socio-economic development, the need for a stable water supply is critical. Therefore, this watershed’s physiography and morphology are studied to aim and facilitate further research in the Sebou region. We rely on the hydrological regime, frequency analysis of extreme flows, rainfall volume, and flood periods forecast to enable that characterization. Our findings determined that the Sebou region is of pluvial type with abundant rainfall, especially in winters due to floods. Moreover, substratum parameters induce a large volume of water resources from upstream to downstream. However, the weak structure of the hydrographic network and the water balance has highlighted a considerable loss of these resources, which handicaps the irrigation system and the supply of drinking water to the region’s cities. Finally, the annual modulus and the different coefficients show hydroclimatic fluctuations of semi-arid climatic conditions, with a temperate winter. Our results suggest a need to monitor water runoff and protect surface soils from flooding and rapid erosion (by planting trees). We also propose installing barriers and a small dam to recharge groundwater and artificially store surface water in this watershed.

Effect of Froude similitude deviation on curved channel simulations: A case study in the Middle Yangtze River

Froude similitude and friction similitude are the two crucial similarity conditions that are often used in physical-scale modeling of rivers.However,models often deviate from Froude similitude when dealing with real-world situations.This study developed several fixed-bed river models with various curvatures to determine the effect of Froude similitude deviation on curved channel modeling.Models were constructed according to the characteristics of the Middle Yangtze River.Differences in longitudinal slope,transverse slope,and main stream line location were measured by varying Froude similitude deviation.The deviations of longitudinal slope and velocity were negligible because friction similitude was accounted for.The transverse slope varied significantly with the Froude similitude deviation,and the main stream line varied with the curvature and Froude similitude deviation.Formulae were derived to estimate the slope deviation.These analyses helped to clarify the feasibility of the method of Froude similitude deviation for curved channels.

长江中上游重要渔业水域环境质量评估

为准确评估长江中上游重要渔业水域水环境质量现状及变化趋势,提高水质评价效率,本研究基于11个水质参数,采用水质指数法(water quality index,WQI)对2006-2021年长江中上游三个重要渔业水域水质进行了综合评价,建立WQI min综合评价模型。结果显示:(1)长江中上游重要渔业水域的水温和高锰酸盐指数呈上升趋势;基于地表水环境质量标准(GB38338-2002),单因素水质评价结果表明监测水域内整体水质处于地表水Ⅴ类水标准,部分年份达劣Ⅴ类,主要污染指标为总氮。(2)通过综合评价方法分析,长江中上游重要渔业水域整体为“良”;2006~2021年长江中上游重要渔业水域水质质量呈逐年改善的趋势,且上游保护区的改善较大。(3)基于WQI方法,确定了长江中上游重要渔业水域的关键水质参数为:总氮、高锰酸盐指数、汞、溶解氧、氨氮、悬浮物以及水温,分别构建了上游保护区、中华鲟保护区以及四大家鱼保护区的WQI_(min)模型;考虑权重和不考虑权重的WQI min模型对比分析表明,考虑权重的WQI min模型的水质评价结果更加准确,该方法可有效评估长江中上游重要渔业水域的水质变化特征并可扩展用于其他水域。

断块油藏高含水井关井后剩余油再动用运移规律微观模拟

基于微观可视化光刻玻璃模型,从微观角度定性、定量研究了断块油藏高含水井关井后剩余油再动用运移规律,并开展了影响因素分析。结果表明:水驱后关井期间剩余油再动用类型主要为滴状、柱状和簇状。关井期间剩余油会沿模型倾斜方向向高部位运移聚集,有利于后续水驱阶段进一步提高驱油效率。地层倾角的增大、原油黏度的减小有利于剩余油再动用;关井时间的增加有利于剩余油向高部位采出端接近聚集;后续水驱阶段注入速度的增大会增加波及面积。

鞍钢鲅鱼圈焦化废水减量及回用改造实践

介绍了鞍钢鲅鱼圈焦化废水处理工艺运行概况,分析了焦化废水工艺存在的问题,通过提升预处理单元、生化处理系统和深度处理系统的功能,新增膜脱盐处理系统,大大提升了焦化废水系统出水水质,中水回用率达到70%以上。最终膜脱盐处理系统的浓水水质指标达到了《炼焦化学工业污染物排放标准》(GB 16171—2012)中的间排标准,全部回用于烧结混料,净水全部回用于循环水系统,实现了焦化废水零排放的目标。

中昆仑山北坡持续性暴雨的水汽输送及其大气三维结构特征

利用基于拉格朗日方法的HYSPLIT_4轨迹模式,结合地基GPS-MET观测资料,对2019年6月24~26日中昆仑山北坡一次持续性暴雨天气大尺度水汽输送特征及水汽源地进行分析,阐明了干旱区强降水期间大尺度环流异常与水汽持续接力输送过程的关系。结果表明:(1)降水前副热带高压(简称副高)位置异常偏西,副高外围偏南气流造成高原增湿明显。强降水期间,副高继续向西北伸展,低纬度水汽沿印度夏季风环流向北输送,经青藏高原接力输送至暴雨区,与塔什干低涡前偏南气流共同构成了中昆仑山北坡持续性强降水的水汽输送通道,水汽持续接力输送造成暴雨区可降水量(PWV)出现两次急剧增湿过程,测站PWV峰值达到气候平均值近2倍。(2)300 hPa温度异常对于本次中昆仑山北坡持续性大暴雨天气水汽输送具有重要的作用。降水前和降水期间,300 hPa暖异常中心激发200 hPa反气旋式环流异常和经向风正异常中心,同时,在暖异常中心南侧(印度半岛北部)和西侧,激发500 hPa反气旋式环流异常中心和气旋式环流异常中心,反气旋式环流后部经向风正异常中心将低纬度地区暖湿气流向北输送,与气旋式环流东部偏南气流在暴雨区汇合,为持续性暴雨的发生提供充沛的水汽供应。

南水北调中线总干渠冰盖糙率观测分析

冰盖糙率是确定渠道冰期输水水位和流量关系的基础参数,一直是明渠冰工程研究的重点之一。鉴于当前大型混凝土渠道冰盖糙率研究成果相当匮乏,以南水北调中线总干渠石家庄以北唯一无输水建筑物的唐河节制闸—放水河节制闸渠段为研究区域,依据全线通水以来唯一生成全渠段封冻冰盖的2016年1—2月逐日水位和流量实测数据,采用伯努利能量方程和谢才-曼宁公式推求渠道糙率,定性定量分析封冻前后渠道糙率变化特征。结果表明:①研究渠段畅流期渠道糙率n b为0.0167,封冻期冰盖综合糙率n c为0.0146,冰盖下表面糙率n i为0.0118。②由于水力磨蚀作用,封冻期冰盖糙率随时间呈波动减小的趋势。③渠道一旦生成封冻冰盖,输水能力大幅降低,仅占渠道设计流量的66.7%。该研究给出了大型混凝土渠道封冻冰盖糙率和输水能力降低的确切数值,以期为冰期输水调度和类似工程设计提供科学依据。

基于生态需水的黄河中游水平衡分析--以沁河流域为例

为推动黄河流域生态保护及高质量发展,解决地表水资源供需矛盾,亟需开展水平衡分析,建立水平衡模型,为水资源合理分配提供参考依据。作为黄河的重要支流,沁河流域位于黄河中游末端,由于近年来上游调水政策的施行以及流域内生活、生产用水的增加,用水矛盾突出,出现了河道断流、入黄水量偏枯等问题。为保障河流生态环境健康,优化引沁入汾跨流域提水工程实施后的流域水资源供需平衡,以2021年为现状年,在“自然-人工”二元水循环研究理论的指导下,运用水平衡分析理论与方法,以河道内生态需水为保障基础,对沁河流域水资源需求、供水能力与供需平衡进行了分析与讨论。结果表明:(1)沁河流域水资源供给和需求在空间分布上具有分异性,上游山西省境内各河段河道内均能够保障适宜的生态需水量,下游河南省境内,仅可满足最小生态需水量;(2)沁河流域可供给水资源总量为10.04×10^(8)m^(3),河道外生产、生活及生态用水总量为8.89×10^(8)m^(3),剩余河道内水量仅为1.15×10^(8)m^(3),仅可满足河流最小生态需水;(3)推算至2030年,流域内工业生产及生活取用地表水量将达到6.98×10^(8)m^(3),河道外用水总量将达到9.81×10^(8)m^(3),剩余水量无法满足最小生态需水。建议采用降低工业用水量、提高农田灌溉用水利用率、推广使用高效节水技术,进一步增强水资源的有效利用,改善流域生态环境。研究结果可为合理规划沁河流域水资源调度提供参考,也可为黄河中游水平衡分析提供范例。

局部降温对输水渠道水华抑制的影响分析

南水北调中线工程自通水以来,发挥着巨大的社会和经济效益,已成为京津地区的主力水源。中线工程输水的水质理化指标相对稳定,但局部渠段存在藻类异常增殖现象,有水华爆发的风险。针对出现的藻类异常增殖问题,在通冷风这一改变局部气象条件的工程措施基础上,建立了澎河—沙河渡槽段平面二维水动力和水质模型,研究了通风位置、通风温度和通风时长等因素对输水渠道水温和藻类的影响。研究表明:水温和叶绿素a浓度均与通风位置、通风温度和通风时长有关,通风温度越低、通风时长越长,平均水温和叶绿素a浓度下降幅度越大,平均水温最高可下降约2℃,叶绿素a浓度最大可降低约54.5%,且仅上游和全渠段通风均可有效降低水温和抑制藻类生长,仅下游通风对水温和藻类的影响较小。因此,采取局部降温的方式可以起到一定的降低叶绿素a浓度的作用,综合考虑藻类抑制效果和工程成本,在水华易爆发渠段的上游通冷风是行之有效的工程措施。

黄河中下游地区耐旱作物扩种的节水降碳协同效应评价

为应对黄河流域农业可持续发展面临的气候变化和水资源短缺挑战,通过推广种植耐旱作物,缓解区域农业用水压力,并分析其节水降碳协同效应,研究设计了趋势照常、缓慢增长、技术引导、政策扶持等不同发展情景,制定了小麦、玉米、高粱、马铃薯4种耐旱作物扩种的节水降碳协同效应分析方案;采用农业节水潜力修正模型和农业降碳潜力模型定量评估了不同情景下耐旱作物扩种的节水效应及降碳潜力。结果表明:黄河中下游地区小麦和玉米的种植面积最大,高粱和马铃薯则相对较小,在政策扶持情景下,2060年小麦、玉米、高粱、马铃薯的扩种规模分别为23.12万、17.34万、34.68万、40.45万hm^(2)。在技术引导和政策扶持情景下,黄河中下游作物的节水效应和降碳效应均显著提升,2060年该区总节水量达153.52亿m^(3)、降碳潜力的平均水平达65.93 t/km^(2)。在黄河中下游地区推广耐旱作物有助于缓解水资源短缺状况,保障区域粮食安全,实现节水降碳增收多重目标。