Impact of prechlorination pH on Pb(II)-NOM complexation and lead release in drinking water distribution systems

The presence of Pb in drinking water resulting from corrosion of lead pipes, solder and fixtures poses a significant threat to public health and safety. Pb is a potent neurotoxin that can impair the cognitive development of children at low concentrations in the bloodstream. During the corrosion of distribution system components containing Pb, precipitate scales form on the interior surfaces of pipes in the distribution system providing a protective barrier between the bulk solution and the pipe surface; the amount of dissolved Pb²⁺ is controlled by the thermodynamics and kinetics of precipitation/dissolution of the particular Pb scales in the system. The solubility and composition of Pb scales phases residing on the pipe surfaces are a function of the background water chemistry (including pH, redox potential and ligand types and concentration). Therefore, considering the conditional stability of lead scales is crucial when making changes to water treatment processes, as alterations in water quality can significantly disrupt the stability of scales in the DWDS, leading to elevated lead concentrations. In distribution systems that employ monochloramine to provide residual disinfection, the formation of Pb(II) scales such as cerussite (PbCO₃) and hydroxyapatite are favored depending on the background water composition (e.g., phosphates added for corrosion protection or carbonate present). Utilities that chloraminate typically implement a prechlorination step in which free chlorine reacts for a specified time prior to ammonia addition to meet disinfection requirements. During the prechlorination step, free chlorine can react with natural organic matter (NOM) to promote Pb release. The formation of NOM-Pb complexes increases the total soluble Pb in distribution systems containing Pb scales. However, before NOM enters the drinking water distribution system (DWDS) oxidation or nucleophilic substitution of NOM functional groups during prechlorination can decrease the extent of Pb(II)-NOM complexation. The relative impact of these processes on Pb(II) concentrations in drinking water distribution systems must be understood for effective Pb control in DWDS’s containing NOM. In this study, the impact of Pb-NOM complexation on Pb(II) release from cerussite (PbCO₃), a Pb scale phase that can form in the DWDS, is studied in batch dissolution experiments with and without prechlorination. Prechorination of the water containing NOM for a 30-minute contact time decreased the amount of Pb released in the presence of NOM with greater reduction at lower pH. The trends in pH were consistent with the greater reactivity between free chlorine and NOM at lower pH. Additionally, excitation emission matrices (EEMs) and near edge x-ray fine structures (NEXAFS) spectroscopy confirmed that chlorination of the NOM led to destruction of electron rich aromatic moieties that function as prominent ligands in Pb(II)-NOM complexation Further, it was found that fewer in number of disinfection byproducts (DBPs) precursors were generated upon reaction of chlorine and NOM at lower pH conditions. These results demonstrate the potential for chlorination to reduce Pb(II)-NOM complexation. The concentrations of total soluble Pb observed in the batch dissolution experiments ranging from 40 ppb to 600 ppb are not representative of dissolved Pb concentrations in the water distribution system as a Pb concentration of 15 ppb necessitates the implementation of corrosion control measures. Further studies are needed to assess the relative impact of Pb(II)-NOM complexation under continuous flow conditions that more closely mimic pipe flow through conditions representative of water distribution system conditions.Environmental and Water Resources Engineerin

Evaluating dairy waste management systems' influence on fecal coliform concentration in runoff

This report examines environmental factors influencing the die-off and transport of fecal coliform bacteria present in wastes applied to the land surface. These factors are examined specifically for dairy waste management systems and the net effect each system has on runoff water quality. A model is developed that considers the effects of precipitation, season, method of wastes storage and application, die-off of the bacteria in storage, die-off of the bacteria on the land surface, infiltration of bacteria into the soil profile, soil characteristics, overland transport of bacteria (runoff), and buffer zones. The model is then applied to the Tillamook Basin in northwestern Oregon to evaluate which waste management procedures significantly decrease bacterial pollution potential in agricultural runoff.Published November 1982. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalo

Environmental impact assessments of the Three Gorges Project in China: issues and interventions

The paper takes China's authoritative Environmental Impact Statement for the Yangzi (Yangtze) Three Gorges Project (TGP) in 1992 as a benchmark against which to evaluate emerging major environmental outcomes since the initial impoundment of the Three Gorges reservoir in 2003. The paper particularly examines five crucial environmental aspects and associated causal factors. The five domains include human resettlement and the carrying capacity of local environments (especially land), water quality, reservoir sedimentation and downstream riverbed erosion, soil erosion, and seismic activity and geological hazards. Lessons from the environmental impact assessments of the TGP are: (1) hydro project planning needs to take place at a broader scale, and a strategic environmental assessment at a broader scale is necessary in advance of individual environmental impact assessments; (2) national policy and planning adjustments need to react quickly to the impact changes of large projects; (3) long-term environmental monitoring systems and joint operations with other large projects in the upstream areas of a river basin should be established, and the cross-impacts of climate change on projects and possible impacts of projects on regional or local climate considered. © 2013 Elsevier B.V.Xibao Xu, Yan Tan, Guishan Yan

DOs and DON'Ts for using climate change information for water resource planning and management: guidelines for study design

Water managers are actively incorporating climate change information into their long- and short-term planning processes. This is generally seen as a step in the right direction because it supplements traditional methods, providing new insights that can help in planning for a non-stationary climate. However, the continuous evolution of climate change information can make it challenging to use available information appropriately. Advice on how to use the information is not always straightforward and typically requires extended dialogue between information producers and users, which is not always feasible. To help navigate better the ever-changing climate science landscape, this review is organized as a set of nine guidelines for water managers and planners that highlight better practices for incorporating climate change information into water resource planning and management. Each DOs and DON'Ts recommendation is given with context on why certain strategies are preferable and addresses frequently asked questions by exploring past studies and documents that provide guidance, including real-world examples mainly, though not exclusively, from the United States. This paper is intended to provide a foundation that can expand through continued dialogue within and between the climate science and application communities worldwide, a two-way information sharing that can increase the actionable nature of the information produced and promote greater utility and appropriate use

Guiding Parameter Estimation for Global Hydrological Models - Elementary Effects

The provided elementary effects are used in the publication J. Kupzig, R. Reinecke, F. Pianosi, M.Flörke and T. Wagener: Guiding Parameter Estimation for Global Hydrological Models (submitted to Environmental Research Letters in Feb 2023). In a large sample study, the Morris Method (Morris 1991) application produces the provided elementary effects using a new lightweight version of the global hydrological model WaterGAP3, called WaterGAPLite

Data from "Including Regional Knowledge Improves Baseflow Signature Predictions in Large Sample Hydrology"

This repository contains data generated for the paper "Including Regional Knowledge Improves Baseflow Signature Predictions in Large Sample Hydrology". The file new_CAMELS_attributes.txt contains new catchment attributes for the CAMELS catchments.The file new_CAMELS_signatures.txt contains baseflow signatures for the CAMELS catchments. Details can be found in the readme

DFID guidance manual on water supply and sanitation programmes

The Department for International Development DFID commissioned this Guidance Manual from the WELL Resource Centre to assist staff and partners to develop effective and sustainable water supply and sanitation programmes. It represents collaboration across a range of professions within the Department and from key UK professionals in the sector. It details inter-disciplinary approaches to planning and implementation of partnership-based programmes. The Manual comprises three chapters and appendices. These take the reader from an overview of the sector, through specific development perspectives, to detailed recommendations for each stage of the project cycle. Chapter 1 is an introduction to water supply and sanitation projects and sets the scene. It describes the WS&S sector with particular focus on the development of services for the poor in both urban and rural areas. Emphasis is placed on the importance of co-operation and partnership and the chapter also introduces the DFID programme and project process. Chapter 2 Principles and practice starts with an inter-disciplinary analysis of key issues and then sets out recommended approaches under seven perspectives: social development; health; environmental sustainability; economic and financial perspectives; institutional perspectives; technical aspects; and hygiene promotion and sanitation promotion. These are explored in some detail so that professional staff in DFID and its partners will gain a better understanding of all the aspects and not just their own speciality. Chapter 3 Water supply and sanitation in the DFID programme and project cycle is the 'how to' part of the manual which brings together the disciplinary perspectives at each stage of the project cycle. The key issues to be taken into account are set out in a helpful 'question and recommendation' format. Appendices include examples of logical frameworks for water supply and sanitation projects

THEORETICAL PRINCIPLES OF INSTITUTIONALIZATION OF INVESTMENT SAFETY

Abstract: The essence of institutionalization as a process of complex combination of formation of institutions (norms, rules, etc.) and institutes (organizations and mechanisms of realization) is considered in the article. The proposed model of the process of full institutionalization, which was tested on the process of institutionalization of investment security. It is determined that factors of a mental character influence the speed and scope of the process of institutionalization

Towards Parameter Estimation in Global Hydrological Models

The provided elementary effects are used in the publication J. Kupzig, R. Reinecke, F. Pianosi, M.Flörke and T. Wagener: Towards Parameter Estimation in Global Hydrological Models (submitted to Environmental Research Letters in Feb 2023). In a large sample study, the Morris Method (Morris 1991) application produces the provided elementary effects using a new lightweight version of the global hydrological model WaterGAP3: WaterGAPLite. elementary_effects.zip : elementary effects for all 50 trajectories and all basins (each trajectory is the result of 18 model runs; used bounds of parameters can be found in the Supplement of the manuscript) results_overview.xlsx: parameter ranks for each basin and different evaluation criteria based on the elementary effects. MC_Sample.csv: normalized parameter samples of the additional Monte-Carlo Simulation (used bounds of parameters are the same as for the Morris method) MC_NSE.csv: resulting NSE values of the Monte-Carlo simulation better_performing_basins.csv: list of basins (using GRDC no.) where minimal NSE is greater than -1 within all Monte-Carlo runs standard_calib.csv: calibrated gamma value for each basin and corresponding evaluation criteria, using the standard calibration for WaterGAP3 (fit to mean discharge) standard_calib_mod.csv: calibrated gamma value for each basin and corresponding evaluation criteria, using a modified version of the standard calibration for WaterGAP3 (maximizing the NSE