Waste stabilization ponds (WSPs) and their variants are one the most widely used wastewater treatment systems in the world. However, the scarcity of systematic performance data from full-scale plants ...has led to challenges associated with their design. The objective of this research was to assess the performance of 388 full-scale WSP systems located in Brazil, Ecuador, Bolivia and the United States through the statistical analysis of available monitoring data. Descriptive statistics were calculated of the influent and effluent concentrations and the removal efficiencies for 5-day biochemical oxygen demand (BOD
), total suspended solids (TSS), ammonia nitrogen (N-Ammonia), and either thermotolerant coliforms (TTC) or Escherichia coli for each WSP system, leading to a broad characterization of actual treatment performance. Compliance with different water quality and system performance goals was also evaluated. The treatment plants were subdivided into seven different categories, according to their units and flowsheet. The median influent concentrations of BOD
and TSS were 431 mg/L and 397 mg/L and the effluent concentrations varied from technology to technology, but median values were 50 mg/L and 47 mg/L, respectively. The median removal efficiencies were 85% for BOD
and 75% for TSS. The overall removals of TTC and E. coli were 1.74 and 1.63 log
units, respectively. Future research is needed to better understand the influence of design, operational and environmental factors on WSP system performance.
•Protozoa and Ascaris persisted longer in fecal sludge than bacteria and viruses.•Median T99 values for bacteria and viruses were 4.8 and 29 days, respectively.•Median T99 values for protozoa and ...Ascaris were >341 and 429 days, respectively.•Pathogen type, design and operational factors explained 67% of variability in decay.•Lime/ash treatment accelerates decay of Ascaris, but possibly only with urea present.
The safe management of fecal sludge from the 3.4 billion people worldwide that use onsite sanitation systems can greatly reduce the global infectious disease burden. However, there is limited knowledge about the role of design, operational, and environmental factors on pathogen survival in pit latrines, urine diverting desiccation toilets, and other types of onsite toilets. We conducted a systematic literature review and meta-analysis to characterize pathogen reduction rates in fecal sludge, feces, and human excreta with respect to pH, temperature, moisture content, and the use of additives for desiccation, alkalinization, or disinfection. A meta-analysis of 1,382 data points extracted from 243 experiments described in 26 articles revealed significant differences between the decay rates and T99 values of pathogens and indicators from different microbial groups. The overall median T99 values were 4.8 days, 29 days, >341 days, and 429 days for bacteria, viruses, protozoan (oo)cysts, and Ascaris eggs, respectively. As expected, higher pH values, higher temperatures, and the application of lime all significantly predicted greater pathogen reduction rates but the use of lime by itself was more effective for bacteria and viruses than for Ascaris eggs, unless urea was also added. In multiple lab-scale experiments, the application of urea with enough lime or ash to reach a pH of 10 – 12 and a sustained concentration of 2,000 – 6,000 mg/L of non-protonated NH3N reduced Ascaris eggs more rapidly than without urea. In general, the storage of fecal sludge for 6 months adequately controls hazards from viruses and bacteria, but much longer storage times or alkaline treatment with urea and low moisture or heat is needed to control hazards from protozoa and helminths. More research is needed to demonstrate the efficacy of lime, ash, and urea in the field. More studies of protozoan pathogens are also needed, as very few qualifying experiments were found for this group.
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Engineered ponds, lagoons, and wetlands have been used for centuries to treat and manage wastewater, and they are still widely used today. They require very few external energy and material inputs ...and provide ecosystem services for communities. This book presents a compilation of guidelines to design ponds, lagoons, and wetlands for the treatment and management of domestic or municipal wastewater, agricultural wastewater, and industrial waste. Sufficient detail and clarity is provided for practitioners to use this book as a reference, and for senior year or graduate college students to develop an understanding of the design concepts for these engineered natural treatment systems.
Homelessness is a persistent problem in the United States in general and in Southern California especially. While progress has been made in reducing the number of people experiencing homelessness in ...the United States from 2007 (647,000) to 2019 (567,000), it remains an entrenched problem. The purpose of this paper is to outline a novel, interdisciplinary academic-practice partnership model to address homelessness. Where singular disciplinary approaches may fall short in substantially reducing homelessness at the community and population level, our model draws from a collective impact model which coordinates discipline-specific approaches through mutually reinforcing activities and shared metrics of progress and impact to foster synergy and sustainability of efforts. This paper describes the necessary capacity-building at the institution and community level for the model, the complementary strengths and contributions of each stakeholder discipline in the proposed model, and future goals for implementation to address homelessness in the Southern California region.
User-friendly, evidence-based scientific tools to support sanitation decisions are still limited in the water, sanitation and hygiene (WASH) sector. This commentary provides lessons learned from the ...development of two sanitation decision support tools developed in collaboration with stakeholders in Uganda. We engaged with stakeholders in a variety of ways to effectively obtain their input in the development of the decision support tools. Key lessons learned included: tailoring tools to stakeholder decision-making needs; simplifying the tools as much as possible for ease of application and use; creating an enabling environment that allows active stakeholder participation; having a dedicated and responsive team to plan and execute stakeholder engagement activities; involving stakeholders early in the process; having funding sources that are flexible and long-term; and including resources for the acquisition of local data. This reflection provides benchmarks for future research and the development of tools that utilize scientific data and emphasizes the importance of engaging with stakeholders in the development process.
As the demand for reliable and safe water supplies increases, both water quality and available quantity are being challenged by population growth and climate change. Greywater reuse is becoming a ...common practice worldwide; however, in remote locations of limited water supply, such as those encountered in military installations, it is desirable to expand its classification to include dishwashing water to maximize the conservation of fresh water. Given that no standards for dishwashing greywater reuse by the military are currently available, the current study determined a specific set of water quality standards for dishwater recycling systems for U.S. military field operations. A tentative water reuse standard for dishwashing water was developed based on federal and state regulations and guidelines for non-potable water, and the developed standard was cross-evaluated by monitoring water quality data from a full-scale dishwashing water recycling system using an innovative electrocoagulation and ultrafiltration process. Quantitative microbial risk assessment (QMRA) was also performed based on exposure scenarios derived from literature data. As a result, a specific set of dishwashing water reuse standards for field analysis (simple, but accurate) was finalized as follows: turbidity (<1NTU), Escherichia coli (<50cfumL−1), and pH (6–9). UV254 was recommended as a surrogate for organic contaminants (e.g., BOD5), but requires further calibration steps for validation. The developed specific water standard is the first for dishwashing water reuse and will be expected to ensure that water quality is safe for field operations, but not so stringent that design complexity, cost, and operational and maintenance requirements will not be feasible for field use. In addition the parameters can be monitored using simple equipment in a field setting with only modest training requirements and real-time or rapid sample turn-around. This standard may prove useful in future development of civilian guidelines.
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•A compact ultrafiltration system was developed for field dishwashing water reuse.•A review was conducted to recommend standards for dishwashing water reuse.•A specific dishwashing water reuse standard was developed for military use.•The water standard was cross-evaluated by monitoring reclaimed dishwashing water.
Microbial water quality is an integral to water security and is directly linked to human health, food safety, and ecosystem services. However, specifically pathogen data and even faecal indicator ...data (e.g.,
E
.
coli
), are sparse and scattered, and their availability in different water bodies (e.g., groundwater) and in different socio-economic contexts (e.g., low- and middle-income countries) are inequitable. There is an urgent need to assess and collate microbial data across the world to evaluate the global state of ambient water quality, water treatment, and health risk, as time is running out to meet Sustainable Development Goal (SDG) 6 by 2030. The overall goal of this paper is to illustrate the need and advocate for building a robust and useful microbial water quality database and consortium worldwide that will help achieve SDG 6. We summarize available data and existing databases on microbial water quality, discuss methods for producing new data on microbial water quality, and identify models and analytical tools that utilize microbial data to support decision making. This review identified global datasets (7 databases), and regional datasets for Africa (3 databases), Australia/New Zealand (6 databases), Asia (3 databases), Europe (7 databases), North America (12 databases) and South America (1 database). Data are missing for low- and middle-income countries. Increased laboratory capacity (due to COVID-19 pandemic) and molecular tools can identify potential pollution sources and monitor directly for pathogens. Models and analytical tools can support microbial water quality assessment by making geospatial and temporal inferences where data are lacking. A genomics, information technology (IT), and data revolution is upon us and presents unprecedented opportunities to develop software and devices for real-time logging, automated analysis, standardization, and modelling of microbial data to strengthen knowledge of global water quality. These opportunities should be leveraged for achieving SDG 6 around the world.
Challenges from globalization, population growth, and climate change require science, technology, and engineering (STEM) professionals to have global competency. However, the impact of international ...experiences on STEM students’ development of these abilities has not been well studied. We assessed the effects of international research experiences in Latin America and the Caribbean (LAC) and Europe on the development of global competency for STEM graduate students from the United States. Research placements in LAC were generally field-based, involving interactions with community members, while placements in Europe were mostly lab-based. Surveys and interviews with participants before and after their trips revealed increases in intercultural abilities for students from all groups. Students who traveled to LAC had higher intercultural abilities before the trip but experienced smaller gains than their counterparts who traveled to Europe. Despite the value in community-based activities for students outside of university settings, more effort is needed to eliminate students’ barriers to understanding communication styles in their host communities.
Sanitation planners make complex decisions in the delivery of sanitation services to achieve health outcomes. We present findings from a stakeholder engagement workshop held in Kampala, Uganda, to ...educate, interact with, and solicit feedback from participants on how the relevant scientific literature on pathogens can be made more accessible to practitioners to support decision-making. We targeted Water, Sanitation and Hygiene (WASH) practitioners involved in different levels of service delivery. Practitioners revealed that different sanitation planning tools are used to inform decision-making; however, most of these tools are not user-friendly or adapted to meet their needs. Most stakeholders (68%) expressed familiarity with pathogens, yet less than half (46%) understood that fecal coliforms were bacteria and used as indicators for fecal pollution. A number of stakeholders were unaware that fecal indicator bacteria do not behave and persist the same as helminths, protozoa, or viruses, making fecal indicator bacteria inadequate for assessing pathogen reductions for all pathogen groups. This suggests a need for awareness and capacity development around pathogens found in excreta. The findings underscore the importance to engage stakeholders in the development of support tools for sanitation planning and highlighted broader opportunities to bridge science with practice in the WASH sector.
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