Drinking Water Production Research Articles

Different drinking water production schemes to treat authentic algae-laden source water: Removal of 2-methylisoborneol in different forms

2-Methylisoborneol (2-MIB) is a typical and common off-flavor pollutant in drinking water, which is produced by cyanobacteria and other microorganisms. 2-MIB exists in several forms, such as intracellular, extracellular; and a fraction of 2-MIB is in free form, while the remaining fraction is combined with coexisting organic matters, which complicates the study of 2-MIB removal mechanisms in drinking water production. This research used raw water containing 2-MIB to investigate the effect of combination processes on the removal of 2-MIB (in different forms) and the coexisting organic substances. With conventional processes alone (coagulation, sedimentation and filtration (CSF)), the removal ratio of 2-MIB was 49.4%, which was due to the removal of intracellular 2-MIB. The removal ratio after CSF increased to 80.0–89.4% when powdered activated carbon (PAC) pretreatment (doses of 10, 20, and 50 mg/L) was applied. The fraction of 2-MIB adsorbed by PAC was in the extracellular free form. For preoxidation, the combination of KMnO4 and CSF (KMnO4-CSF) was more effective than H2O2-CSF and NaClO-CSF but less effective in removing dissolved organic carbon (DOC) than the other two methods. H2O2 exhibited the best overall removal of 2-MIB and DOC after CSF. NaClO caused the release of a large amount of intracellular 2-MIB. The removal ratio of 2-MIB by nanofiltration (NF, ∼300 Da) alone was ∼ 87%, and the total removal ratio with PAC, CSF, and NF was as high as 98%. The findings are of particular significance for selecting the combined drinking treatment processes (e.g. PAC-CSF-NF) when odorous compounds are present in high concentrations.

A review on the centralised municipal sewage and wastewater treatment unit processes

Wastewater release into water bodies from industries, residential areas and institutions poses a great challenge to public health in many countries of the world, especially in the developing ones like Nigeria and Pakistan. The way and manner by which wastewater is treated (physico-chemically or biologically) has a significant impact on the health of humans and the receiving ecosystem. Wastewater treatment is important and its main objective is to reduce the concentrations of its pollutants to limits set by regulatory bodies before discharge to receiving waters or further treated for other purposes such as recreation, irrigation and drinking water production. Among the major parameters that are usually being treated are the dissolved oxygen (DO), pH, Turbidity, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Nitrogen (NO3-N, NH4-N), Phosphorus, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), microbes etc. Several treatment methods have been in use, however, this paper presents a comprehensive overview of the conventional approach that employs some physical, chemical and biological processes at the preliminary, primary, secondary and tertiary stages in the treatment of water and wastewater from different sources.

Towards climate-robust water quality management: Testing the efficacy of different eutrophication control measures during a heatwave in an urban canal

Harmful algal blooms are symptomatic of eutrophication and lead to deterioration of water quality and ecosystem services. Extreme climatic events could enhance eutrophication resulting in more severe nuisance algal blooms, while they also may hamper current restoration efforts aimed to reduce nutrient loads. Evaluation of restoration measures on their efficacy under climate change is essential for effective water management. We conducted a two-month mesocosm experiment in a hypertrophic urban canal focussing on the reduction of sediment phosphorus (P)-release. We tested the efficacy of four interventions, measuring phytoplankton biomass, nutrients in water and sediment. The measures included sediment dredging, water column aeration and application of P-sorbents (lanthanum-modified bentonite - Phoslock® and iron-lime sludge, a by-product from drinking water production). An extreme heatwave (with the highest daily maximum air temperature up to 40.7 °C) was recorded in the middle of our experiment. This extreme heatwave was used for the evaluation of heatwave-induced impacts. Dredging and lanthanum modified bentonite exhibited the largest efficacy in reducing phytoplankton and cyanobacteria biomass and improving water clarity, followed by iron-lime sludge, whereas aeration did not show an effect. The heatwave negatively impacted all four measures, with increased nutrient releases and consequently increased phytoplankton biomass and decreased water clarity compared to the pre-heatwave phase. We propose a conceptual model suggesting that the heatwave locks nutrients within the biological P loop, which is the exchange between labile P and organic P, while the P fraction in the chemical P loop will be decreased. As a consequence, the efficacy of chemical agents targeting P-reduction by chemical binding will be hampered by heatwaves. Our study indicates that current restoration measures might be challenged in a future with more frequent and intense heatwaves.

Vortex Impeller-Based Aeration of Groundwater

Iron oxidation and removal from groundwater is a necessary and costly process in drinking water production. In most cases, iron removal is done via aeration, succeeded by precipitation. Most systems for aeration are based on increasing the interfacial area via injecting air in the system or spraying. Both methods have disadvantages, like clogging and formation of aerosols. In this study, a new vortex-based flow-through reactor consisting of a cylindrical tank with an impeller located at the bottom was studied regarding its aeration and iron oxidation capabilities in groundwater. During the aeration experiments, the flow rate, impeller rotation and aerated volume were varied. A nondimensional constant α was proposed to relate the system’s physical characteristics and its aeration capabilities, expressed in dissolved oxygen and system volumetric mass transfer coefficient (KLa). Three distinct operational regimes were defined: formation, complete and bubble regime. These regimes showed very specific characteristics regarding the air–water interface structure and the area to volume ratio, resulting in different aeration capabilities and iron oxidation efficiency values. The system presented KLa values similar to commercially available aeration systems, especially inside the bubble regime. By using dimensionless coefficients, the presented analysis provided the basis for the design of continuous impeller aeration and oxidation systems of arbitrary size.

Ultrablack Poly(vinyl alcohol)‐Graphite Composite Xerogel with Vertically Arranged Pores for Highly Efficient Solar Steam Generation and Desalination

Ultrablack materials have attracted wide attention due to their high light absorbance and efficient photothermal conversion used in the field of solar steam generation to alleviate the drinking water crisis. Herein, ultrablack and low‐cost poly(vinyl alcohol)‐graphite composite xerogels (PGCXs) that have vertically arranged pores and high thermal conductivities are fabricated. The PGCX‐50% shows high light absorbance (95.44%), good wettability, and a water evaporation rate of 1.24 kg m−2 h−1 under 1 sun illumination when coupled in a two dimensional (2D) evaporator. To further improve the solar steam generation performance, the PGCX‐50% is switched to a three dimensional (3D) evaporator by rotating it. Under 1 sun illumination, the 3D evaporator has a highest water evaporation rate of 3.80 kg m−2 h−1, which is 3.07 times that of the 2D evaporator, due to its larger evaporation area and higher surface area at subambient temperature. Finally, a heatsink‐like 3D evaporator is designed and a water evaporation rate of up to 9.54 kg m−2 h−1 is achieved when coupled with wind energy. The high water evaporation rates of the PGCX even in concentrated brines ensure its great potential for drinking water production and seawater desalination.

Application of Q-methodology for identifying factors of acceptance of spatial planning instruments

Worldwide, urbanization leads to increased pressure on prime agricultural land with irreversible impacts on the provision of life-supporting services such as food and drinking water production or habitat for plants and animals. As a basis for designing new policy instruments to protect soil resources, we applied Q-methodology to assess factors that influence the acceptance or rejection of such instruments. Using an online survey and interviews, we identified different social perspectives and their respective argumentation patterns. The results show that effect on people, institutional embeddedness, trust in the acting institutions, and the overall understanding of the instrument are the most important factors for the acceptance of policy instruments fostering the sustainable use of soil resources. During the interviews, idealistic and fact-based arguments were more important than person-based arguments. Based on our results, communication strategies in the policy-making process can be improved and tailored to the identified characteristics of the social perspectives.

Over 11 kg m-2 h-1 Evaporation Rate Achieved by Cooling Metal-Organic Framework Foam with Pine Needle-Like Hierarchical Structures to Subambient Temperature.

Solar steam generation has become a hot research topic because of its great potential to alleviate the drinking water crisis without extra energy input. Although some efforts focusing on designing spatial geometry have been made to multiply the evaporation performances of up-to-date three-dimensional evaporators, they still have some shortcomings, such as low material and space utilization efficiencies, complex spatial geometry, energy loss due to the hot solar absorption surface, and salt crystallization due to inefficient water supply. Herein, a biomimetic copper-based metal-organic framework (Cu-Cu(OH)2-MOF) foam sheet with interconnected pores and pine needle-like hierarchical structures consisting of Cu(OH)2 nanowires and MOF nanowhiskers is fabricated. The pine needle-like hierarchical structures of Cu-Cu(OH)2-MOF foam contribute to absorbing solar energy and supplying sufficient water by trapping incident light and enhancing the capillary force, respectively. Inspired by drying clothes outside under solar irradiation, through exposing one end of the Cu-Cu(OH)2-MOF foam to air, the biface evaporator achieves a subambient evaporation surface temperature and an evaporation rate of up to 3.27 kg m-2 h-1 under only one sun illumination. Furthermore, when coupled with an air flow, the biface evaporator realizes an excellent evaporation rate of 11.58 kg m-2 h-1 with an energy efficiency of 160.07% even in seawater, ensuring its great application prospect to be used in drinking water production and seawater desalination.

The impact of micropollutants on native algae and cyanobacteria communities in ecological filters during drinking water treatment

An attractive alternative for drinking water production is ecological filtration. Previous studies have reported high removal levels of pharmaceutical and personal care products (PPCPs) by this technology. Algae and cyanobacteria play an important role in the biological activity of ecological filters. The aim of this study was to characterize and identify the community of algae and cyanobacteria in relation to its composition, density and biovolume from 22 ecological filters that received spikings of 2 μg L−1 PPCPs. For algae and cyanobacteria species, triplicate samples were collected before and 96 h after each spiking from the interface between the top sand layer of the ecological filters and the supernatant water. Results show that Chlorophyceae and Cyanobacteria were present in high numbers of taxa and abundance. The specie Lepocinclis cf. ovum (Euglenophyceae) had the highest percentage occurrence/abundance and frequency into the filters, indicating a possible tolerance by Lepocinclis cf. ovum to the concentration of selected PPCPs. Although the concentration of PPCPs did not affect the treated water quality, they did affect the algae and cyanobacteria community. No differences were detected between filters that received a single PPCP and filters that received a mixture of the six compounds. Also, changes in the composition of algae and cyanobacteria communities were observed before and 96 h after the spikings.

Implementation of the Distribution Requirement Planning Method in Optimizing the Distribution of Packaged Drinking Water Products

CV Athaya Mineral is an industry that runs its business in the production and distribution of bottled drinking water. At the time of distribution of its products, errors often occur, namely the interpretation of demand data in each distribution chain and information received. The purpose of this study was to determine the optimal lotting technique for the distribution of these products using the Distribution Requirement Planning (DRP) method. From the results of data processing, the retail value of Kede Osa was obtained with a total cost of Rp. 233.696, New Store retail with an amount of Rp. 417,336, retail Ari JP Rp. 99,727, Simpang Remi retail Rp. 165,140, retail Mita Jaya Rp. 619,981. The conclusion of this study is the distribution of the Distribution Requirement Planning method for all Dance products (Glass, Small Bottles, Medium Bottles, and Gallons) to five retailers (Kede Osa, Toko Baru, Ari JP, Simpang Remi, and Mita Jaya) using Economic Order Quantity (EOQ) is a lotting technique with the cheapest distribution costs, except for New Store retailers using the Lot For Lot (LFL) lotting technique.

Does substituting reprotoxic solvents during ultrafiltration membrane fabrication really mitigate environmental impacts? Focus on drinking water production

The purpose of this research is to fill knowledge gaps on the relevance of solvent substitution from a life cycle perspective and to put forth relevant operating conditions for possible process optimisation and eco-design. Solvents commonly used to prepare ultrafiltration membranes for drinking water applications are indeed identified by the European REACH regulation for their potential reproductive toxicity and are the subject of research as regards their substitution. Coupling Life Cycle Assessment (LCA) with process modelling allowed to compare conventional membranes (cellulose triacetate as polymer, NMP as solvent) to biosourced membranes (cellulose diacetate as polymer, methyl lactate as solvent). Although methyl lactate fabrication leads to lower environmental scores than NMP fabrication (32% and 10% less GWP100 and ReCiPe Endpoint, respectively), LCA scores for membrane fabrication are similar (1.9 points ReCiPe for 1 m2 membrane) or slightly different, i.e. 11 kg CO2-eq and 9.4 kg CO2-eq for 1 m2 of conventional and biosourced membrane, respectively. From an environmental point of view, solvent substitution has little influence on impacts. Rather, environmental hotspots lie in the operation stage, with impact scores about 10,000 times higher than those of membrane fabrication, which holds out considerable prospects for the optimisation of operating conditions on drinking water plants.

Selective pressure on microbial communities in a drinking water aquifer – Geochemical parameters vs. micropollutants

Groundwater quality is crucial for drinking water production, but groundwater resources are increasingly threatened by contamination with pesticides. As pesticides often occur at micropollutant concentrations, they are unattractive carbon sources for microorganisms and typically remain recalcitrant. Exploring microbial communities in aquifers used for drinking water production is an essential first step towards understanding the fate of micropollutants in groundwater. In this study, we investigated the interaction between groundwater geochemistry, pesticide presence, and microbial communities in an aquifer used for drinking water production. Two groundwater monitoring wells in The Netherlands were sampled in 2014, 2015, and 2016. In both wells, water was sampled from five discrete depths ranging from 13 to 54 m and was analyzed for geochemical parameters, pesticide concentrations and microbial community composition using 16S rRNA gene sequencing and qPCR. Groundwater geochemistry was stable throughout the study period and pesticides were heterogeneously distributed at low concentrations (μg L−1 range). Microbial community composition was also stable throughout the sampling period. Integration of a unique dataset of chemical and microbial data showed that geochemical parameters and to a lesser extent pesticides exerted selective pressure on microbial communities. Microbial communities in both wells showed similar composition in the deeper aquifer, where pumping results in horizontal flow. This study provides insight into groundwater parameters that shape microbial community composition. This information can contribute to the future implementation of remediation technologies to guarantee safe drinking water production.

Interspecies Interactions of the 2,6-Dichlorobenzamide Degrading Aminobacter sp. MSH1 with Resident Sand Filter Bacteria: Indications for Mutual Cooperative Interactions That Improve BAM Mineralization Activity.

Bioaugmentation often involves an invasion process requiring the establishment and activity of a foreign microbe in the resident community of the target environment. Interactions with resident micro-organisms, either antagonistic or cooperative, are believed to impact invasion. However, few studies have examined the variability of interactions between an invader and resident species of its target environment, and none of them considered a bioremediation context. Aminobacter sp. MSH1 mineralizing the groundwater micropollutant 2,6-dichlorobenzamide (BAM), is proposed for bioaugmentation of sand filters used in drinking water production to avert BAM contamination. We examined the nature of the interactions between MSH1 and 13 sand filter resident bacteria in dual and triple species assemblies in sand microcosms. The residents affected MSH1-mediated BAM mineralization without always impacting MSH1 cell densities, indicating effects on cell physiology rather than on cell number. Exploitative competition explained most of the effects (70%), but indications of interference competition were also found. Two residents improved BAM mineralization in dual species assemblies, apparently in a mutual cooperation, and overruled negative effects by others in triple species systems. The results suggest that sand filter communities contain species that increase MSH1 fitness. This opens doors for assisting bioaugmentation through co-inoculation with "helper" bacteria originating from and adapted to the target environment.

Reuse of sludge from drinking water production in dye wastewater treatment of textile industry

Reuse of sludge from drinking water production in dye wastewater treatment of textile industry

Solar dome integration as technical new in water desalination: case study Morocco region Rabat-Kenitra

This paper presents a study of the solar dome system that is considered as one of the most important economical solutions in the domain of drinking water production. For this, a mathematical model was built from equations describing the optical and thermal phenomenon involved in this process. The concentration of radiation and the heat flow were simulated in each 0.1m² of the dome using the metrological parameters of Morocco’s region Rabat-Salé-Kenitra. The results can follow the evolution of the temperature of glass, salt water, point dew temperature, saturation pressure and evaporation rate as well as humidity reached in August month for the study zone. For this, a numerical implementation on Matlab and Ansys are compared with measurements for the same parameters shown in the domain study of single slope. The comparison results are more significant by the rise of the ray concentration rate reached to 99% if the inclination angle of the heliostat is divided into three intervals. The saturation pressure increases as long as with the rate of evaporation and the humidity that produces ordinary daily fresh water.

Physico-Chemical Characterization of Sludge from the Goudel Drinking Water Production Plant in Niamey (Niger)

Population growth and increasing needs make our current societies a considerable source of environmental threats. Going towards sustainable cities where harmony exists between economic, socio-cultural and environmental issues is a necessity that is essential if we want to bequeath a livable world to future generations. Cities produce huge quantities of domestic and industrial waste, the management of which is becoming a growing problem for city managers. Located on the banks of the Niger River, the city of Niamey, capital of the Republic of Niger, is supplied with drinking water from this river. Significant quantities of sludge are produced by the plant following the treatment of this water. This study focuses on the physico-chemical characterization of this sludge which is now directly discharged into the Niger River. A total of 12 samples of pasty sludge taken from the pre-settling ponds were analyzed. The samples were previously dried, crushed, sieved and packaged. Physical (pH, EC and particle size), chemical (Ca, Mg, Na, K, CEC, AE, P, C, MO and N) and metallic trace elements (Pb, Ni, Cu, Zn, Cd, Mn) parameters and Al) were analyzed in the laboratory. The results show that the sludge is weakly acidic (pH between 4.16 and 5.71), conductive (% to 77.71% clay). The nutrient content is low in nitrogen (admissible in residual materials (French decree of 08/01/1998). This sludge can be recovered, especially in agriculture.

Aquifer Upper-Middle Pleistocene (qp2-3) vulnerability assessment using origin DRASTIC and improved AHP- DRASTIC in Ho Chi Minh City

Groundwater protection against anthropogenic sources, including the exploitation and use of groundwater sources, the release of wastes into the soil environment, changes in land cover, and the process of groundwater recharge is of paramount importance for protecting human health by securing clean groundwater for drinking water production. The identification of a groundwater contamination risk zone has been found to be a necessary and useful approach for managing this valuable resources. In the present study, the improved DRASTIC index model with optimized AHP weights technique applied for the assessment of groundwater vulnerability in the Upper-Middle Pleistocene aquifer of Ho Chi Minh City. The dataset of AHP weights of the DRATIC component parameters calculated from the data of experts' evaluation of the characteristics of the study area, demonstrates very clearly the importance of the component parameters of the study area. The results of GIS and AHP- DRASTIC have showed three levels: the low vulnerability zone is 60,98%, medium and high vulnerability zones account for 25,64% and 13,38% of the total study area, respectively. According to the level of vulnerable zoning, the highly vulnerable area is one that has exposed aquifers or shallow aquifer roofs, significant recharge (added directly from rains or runoff from the surface flows in associated with contaminants from runoff flows), coverage rates, and extensive mining activities constitute a high-risk index for groundwater vulnerability. This result suggests that the GIS-based DRASTIC index model is a useful tool to assist policymakers in formulating solutions for the sensible use of water resources, as well as to identify regions where groundwater exploitation is limited.

"Industrialising" the capacity building of local entrepreneurs. A case study of 1001fontaines' "4G Project" in Cambodia

In Cambodia, only 16% of the population in rural areas has access to safely managed and clean water supply services, putting the health of 10.12 million people at stake. (Cambodia's Voluntary National Review 2019 of the Implementation of the 2030 SDG Agenda). 1001fontaines, a community-based enterprise located mainly in Cambodia, responds to this issue by enabling the production of safe drinking water directly in the targeted communities, through the establishment of small water enterprises. These units, called water kiosks, are entrusted to local entrepreneurs and supported in the long run thanks to a franchise model. In 2014, 1001fontaines su ered from low-performing water kiosks, which impacted the viability of the whole portfolio. As a result, 1001fontaines decided to launch the so-called "4G" capacity building project to upgrade the initial and continuing training of water entrepreneurs, expand distribution channels, and further leverage the local "O-We" brand to reach more bene ciaries. The "4G project" was implemented from 2014 to 2015, and resulted in the identi cation of best practices to be followed by every water entrepreneur. Since 2016, 1001fontaines has generalised the use of these best practices to build the capacities of new entrepreneurs. This case study aims to investigate the impact of the "4G project" and its conclusion on the water kiosks' performance and on 1001fontaines' ability to better and faster scale up its approach in Cambodia.

Rationale for the use of photocatalysis for natural and drinking water purification from pollutants of biological origin

Objective. To evaluate the effectiveness of photocatalytic methods of oxidation of organic substances for the preparation of drinking water. To show the expediency of the use of the described method for the design of wastewater treatment facilities.Materials and methods. The oxidation degrees of 58 organic substances of various hazard classes were studied. The sampling frame was based on two characteristics: origin (biological and artificial) and the oxidation state stated in different sources.Results. A high efficiency of photocatalysis for the destruction of organic substances in wastewater from various industries has been shown: the degrees of oxidation range from 70 to 100 %.Conclusion. Photocatalysis can be used to design wastewater treatment facilities with a view to reducing the probability of biological pollution of natural waters intended for drinking water production.

Micropollutant abatement with UV/H2O2 oxidation or low-pressure reverse osmosis? A comparative life cycle assessment for drinking water production

Micropollutants (MP) are undesired in drinking water. Advanced oxidation processes (AOP) or low-pressure reverse osmosis membrane filtrations (LPRO) can be used to remove them during the water purification process. For a specific case, two treatment scenarios were compared with a life cycle assessment (LCA), using three impact assessment methods (Ecological Scarcity 2013, ILCD 2011, EDIP 2003). Scenario 1 (AOP-based) was a UV/H2O2 oxidation with a subsequent granular activated carbon (GAC) filter to remove excess H2O2 before soil infiltration. Scenario 2 (LPRO-based) was a side-stream treatment with an ultrafiltration (UF) and low-pressure reverse osmosis (LPRO) filtration before soil infiltration and the LPRO retentate was treated with O3/H2O2 and subsequent granular activated carbon (GAC) filter before discharge back into Rhine. Sensitivity analyses were performed on the relevant contributors to evaluate the robustness of the results. LCA results showed that in the base-line scenario (electricity from renewable energy sources) the LPRO-based treatment had notably fewer environmental impacts than the AOP-based treatment, which was confirmed with three impact assessment methods. Key contributors to the impacts were mostly operating resources, i.e., electricity, H2O2, liquid O2 for ozone generation and GAC, but also construction resources in the LPRO process. The electrical energy source was decisive for the results: with a share of renewable energy sources <80%, the AOP-based treatment was the better option due to its lower specific energy demand. The optimization of treatment conditions, such as lower H2O2 concentration at an increased UV fluence; different H2O2:O3 molar ratios; or extended GAC utilization time could influence the environmental impact within a range of ±10–30%. Environmental benefits, i.e. the reduction of potential hazardous effects of 21 MPs, were determined with EDIP 2003 and USEtox for both treatment scenarios. The estimated benefits were negligible in comparison to the environmental burden caused by the treatments, thus would not be justified from a global LCA impact-benefit perspective. However, because of several uncertainties and lack of data, the inclusion of treatment benefits in LCAs for drinking water purification requires further research.

Efficient Solar-Driven Water Purification Based on Biochar with Multi-Level Pore Bundle Structure for Preparation of Drinking Water.

Water is an important source for humankind. However, the amount of available clean water has rapidly reduced worldwide. To combat this issue, the solar-energy-driven evaporation technique is newly proposed to produce clean water. Here, biochar derived from sorghum stalk with a multi-level pore bundle structure is utilized to fabricate a solar-driven evaporator for the first time. The biochar displays rapid water transfer and low thermal conductivity (ca. 0.0405 W m−1 K−1), which is vitally important for such an application purpose. The evaporation rate and energy conversion efficiency of the solar evaporator based on carbonized sorghum stalk can achieve up to 3.173 kg m−2 h−1 and 100%, respectively, which are better than most of the previously reported biomass materials. Furthermore, the carbonized sorghum stalk also displays good resistance to salt crystallization, anti-acidic/basic, and organic pollutants by producing drinking water using seawater, acidic/basic waste water, and organic polluted water, respectively. The direct application of processed water in food production was also investigated. The present solar steam evaporator based on the carbonized sorghum stalk has the potential to create practical drinking water production by using various water sources.