Conventional and non-conventional adsorbents for wastewater treatment

Environmental Chemistry Letters - The removal of contaminants from wastewaters is a major challenge in the field of water pollution. Among numerous techniques available for contaminant removal,...     

Environmental quality of Korean coasts as determined by modified Shannon–Wiener evenness proportion

The coast of the Korean peninsula experiences a range of human impacts, including pollution, shipping, reclamation, and aquaculture, that have motivated numerous local studies of macrobenthic organisms. In this paper, 1,492 subtidal stations were compiled from 23 studies (areas) to evaluate environmental quality on a broader scale. A common index in biomonitoring, Shannon–Wiener evenness proportion (SEP), could not incorporate azoic or single-species samples. This shortcoming was overcome by developing an inverse function of SEP (ISEP), which was positively correlated with independent measures of water quality available for nine sites and was not biased by the size of the sampling unit. Additionally, at Shihwa Dike, where samples were collected before and after reinstating a tidal connection with the ocean, ISEP values improved over time, as expected. Thus, it is now possible to assign Korean subtidal sites to seven ISEP “grades” and to use their values and trends to guide coastal management.     

Reservoir Sedimentation Rates in the Little Washita River Experimental Watershed,Oklahoma: Measurement and Controlling Factors

Forty‐five flood control reservoirs, authorized in the Watershed Protection and Flood Prevention Act 1954, were installed by United States Department of Agriculture (USDA) between 1969 and 1982 in the Little Washita River Experimental Watershed (LWREW), located in central Oklahoma. Over time, these reservoirs have lost sediment and flood storage capacity due to sedimentation, with rates dependent on upstream land use and climate variability. In this study, sedimentation rates for 12 reservoirs representing three major land use categories within LWREW were measured based on bathymetric surveys that used acoustic profiling system. Physiographic and climate attributes of drainage area of surveyed reservoirs were extracted from publicly available data sources including topographic maps, digital elevation models, USDA Natural Resource Conservation Service soils, and weather station databases. Correlation, principal component analysis, and stepwise regression were utilized to analyze the relationship between normalized reservoir sedimentation rates (ReSRa) and the drainage area characteristics to determine the major variables controlling sedimentation within the LWREW. Percent of drainage area with extreme slopes, saturated hydraulic conductivity, and maximum daily rainfall event recorded in spring explained most of the variability in ReSRa. It was also found that percent reduction in reservoir surface area can be used as a surrogate for estimating ReSRa. The implications of the results are discussed.     

Road Erosion and Delivery Index (READI): A Model for Evaluating Unpaved Road Erosion and Stream Sediment Delivery

The Road Erosion and Delivery Index (READI) is a new geographic information system–based model to assess erosion and delivery of water and sediment from unpaved road networks to streams. READI quantifies the effectiveness of existing road surfacing and drain placements in reducing road sediment delivery and guides upgrades to optimize future reductions. Roads are draped on a digital elevation model and parsed into hydrologically distinct segments. Segments are further divided by engineered drainage structures. For each segment, a kinematic wave approximation generates runoff hydrographs for specified storms, with discharge directly to streams at road–stream crossings and onto overland‐flow plumes at other discharge points. Plumes are attenuated by soil infiltration, which limits their length, with delivery occurring if plumes intersect streams. Sediment production and sediment delivery can be calculated as a relative dimensionless index. READI predicts only a small proportion of new drains and new surfacing results in the majority of sediment delivery reductions. The model illustrates how the spatial relationships between road and stream networks, controlled by topography and network geometries, influence patterns of road–stream connectivity. READI was applied in seven northern California basins. The model was also applied in a recent burn area to examine how reduced hillslope infiltration can result in increased hydrologic connectivity and sediment delivery.     

An Assessment of U.S. Stream Compensatory Mitigation Policy: Necessary Changes to Protect Ecosystem Functions and Services

Compensatory mitigation of impacted streams and wetlands has increased over the past two decades, with the associated industry spending over US$2.9 billion in aquatic restoration annually. Despite these expenditures, evaluations by the National Research Council and U.S. Government Accountability Office have provided evidence that compensatory mitigation practices are failing to protect aquatic resource functions and services, and vague federal policy and inadequate evaluation of compensatory mitigation projects are to blame. To address these weaknesses, an update to federal regulations on compensatory mitigation was released in 2008. Additionally, the 2012 Reissuance of Nationwide Permits, some of which affects compensatory stream mitigation, was recently published. Current policy, as reflected in these documents, still uses nonspecific language to direct compensatory stream mitigation leaving most implementation decisions to the local U.S. Army Corps of Engineers district. The majority of federal mitigation policy has focused on wetland compensation, with other aquatic resources receiving less attention (e.g., streams). In this article, weaknesses of current policy are discussed, as are suggested policy changes to minimize the loss of stream ecosystem functions and services. Compensatory mitigation policy should clearly define key terms, incorporate adaptive management procedures, and provide guidelines for determining mitigation costs and compensation ratio requirements.     

Assessment of Residential Rain Barrel Water Quality and Use in Cincinnati,Ohio1

The collection, storage, and reuse of rainwater collected in rain barrels from urban rooftop areas assists municipalities in achieving stormwater management objectives and in some areas also serves as an adjunct resource for domestic water supplies. In this study, rainwater reuse and levels of select microbial indicators were monitored for six residential rain barrels located in the Shepherd Creek watershed of Cincinnati, Ohio. Water from rain barrels typically had poor microbial quality and was used for watering indoor and outdoor plants. Rain barrel water chemistry was slightly acidic, exhibited wide ranges in conductivity, turbidity, and total organic carbon (TOC) concentrations and gave no evidence of the presence of cyanobacterial microcystin toxins. Selected microbial water‐quality indicators indicated that counts of total coliform and enterococci were consistently above U.S. Environmental Protection Agency standards for secondary recreational contact water‐quality standards. Residential rain barrels can provide water appropriate for low‐contact reuses (such as plant watering), although there may be transient periods of high levels of indicator bacteria in the collected water.     

Support of sustainable management of nitrogen contamination due to septic systems using numerical modeling methods

Nitrogen contamination is a serious concern to sustainable environmental management, and one important source of nitrogen contaminant is due to wastewater treatment using onsite sewage treatment and disposal systems (OSTDS, a.k.a., septic systems). This paper presents a study in which numerical modeling is used to support sustainable decision-making and management of nitrogen contamination by utilizing a recently developed GIS-based software, VZMOD, a Vadose Zone MODel for simulating nitrogen transformation and transport in vadose zone between drainfield of septic systems and water table. VZMOD is based on a physical model of unsaturated flow and nitrogen transformation and transport, and the model is solved numerically using the finite element methods. This is the major difference between VZMOD and other GIS-based software of nitrogen modeling. Using GIS techniques, VZMOD considers spatial variability of a number of hydrogeologic parameters such as hydraulic conductivity and porosity. A unique feature of VZMOD is that VZMOD addresses spatial variability of water table by using VZMOD together with ArcNLET, an ArcGIS-based software developed to simulate groundwater flow and nitrate load from septic systems to surface water bodies. VZMOD is designed to execute in different modes to be compatible with different levels of data availability in various management projects of nitrogen contamination. This paper presents an application of VZMOD at a neighborhood with hundreds of septic systems and heterogeneous hydraulic conductivity, porosity, and water table depth. The modeling results indicate that using septic systems at the considered neighborhood is unsustainable and more management means are necessary.     

Community Sustainability Plans to enable change towards sustainable practice – a Scottish case study

There is a need for a global shift towards a low-carbon society and this requires action at the local level. The aim of the study into sustainable community development is to clarify the role of a community as a whole rather than the role of individuals within that community. Mixed methods of literature review and empirical study have been used to translate the knowledge and experience with urban sustainable development into empirical knowledge of a rural, market town setting. The exemplary case study is the Scottish market town Huntly. The main findings of the study show the need for three ingredients for a Community Sustainability Plan for a town such as Huntly. Community involvement is crucial in developing such plans in a rural setting. Further research in more remote settings, e.g. coastal and island communities, is needed to allow broader conclusions on rural sustainable development.     

Exploring the co-benefits (and costs) of home gardening for biodiversity conservation

ABSTRACT

Despite growing evidence pointing to the multiple benefits of home gardening, few studies have considered the health and well-being benefits perceived by gardeners who are principally motivated by biodiversity conservation (i.e. home gardening for biodiversity conservation). This study explores the environmental, social and economic co-benefits (and costs) of home gardening for biodiversity conservation in the City of Winnipeg, Canada. A total of 42 semi-structured interviews (30–60?min each) were conducted with 50 home gardeners who were formally certified or locally recognised for undertaking multiple gardening activities that promote biodiversity conservation. Thematic analysis revealed that study participants self-reported a range of environmental, psychological, physiological and social outcomes associated with their home gardening experiences. Despite home gardening often being a solitary activity, most gardeners valued the multiple forms of social interaction that occurred during important social events in their garden, or when connecting with passers-by. Home gardeners also cited benefits related to connection to nature and place attachment; attention restoration; reduced stress and anxiety; improved mood; satisfaction and pride; increased self-esteem and courage to do things differently in life; and, important education or learning opportunities. However, conflicts relating to the nexus between biodiversity and perceived tidiness of gardens emerged, which raise important ethical and social justice issues for sustainability planning. We compare key insights to the benefits (and costs) of community gardening and make some recommendations for future research, including how to engage more disadvantaged groups in gardening for conservation.     

IDW‐Plus: An ArcGIS Toolset for Calculating Spatially Explicit Watershed Attributes for Survey Sites

Watershed characteristics such as land‐use and land‐cover affect stream condition at multiple scales, but it is widely accepted that conditions in close proximity to the stream or survey site tend to have a stronger influence. Although spatially weighted watershed metrics have existed for years, nonspatial lumped landscape metrics (i.e., areal mean or percentage) are still widely used because relatively few technical skills are needed to implement them. The Inverse Distance Weighted Percent Land Use for Streams (IDW‐Plus) custom ArcGIS toolset provides the functionality to efficiently calculate six spatially explicit watershed metrics which account for the Euclidean or flow length distance to the stream or outlet, as well as the probability for overland runoff. These include four distance‐weighted metrics, those being inverse Euclidean distance to the stream or outlet, and the inverse flow length to the stream or outlet. Two tools are also included to generate hydrologically active (i.e., runoff potential), inverse flow length to the stream or outlet metrics. We demonstrate the tools using real data from Southeast Queensland, Australia. We also provide detailed instructions, so readers can recreate the examples themselves before applying the tools to their own data.