Treatment Unit Processes Research Articles

Laboratory Experiments on Remediation of Landfill Leachate Contamination with Permeable Reactive Barriers (PRBs) of Reactive Media Derived from Waste

Groundwater at landfills is often contaminated with heavy metals. Permeable reactive barrier (PRB), a potential in-situ treatment system, was investigated in this study, using 'composite reactive media' (COM), primarily composed of waste materials, to remediate heavy metals in groundwater. The COM consisted of 40% Brick and Mortar Waste (BMW), 40% Biochar (BC), 10% Granular Activated Carbon (GAC), and 10% Zeolite, based on volume. In an up-flow column, the average removal efficiencies of Fe, Pb, Cu, As, Mn, Zn, and Cd were 70.9±2.7, 80.9±3.2, 72.2±1 .6, 76.3±2.5, 81.6±6.3, 88.0±2.0, and 67.3±4.6%, respectively. In a bench-scale COM-filled PRB (0.85 x 0.25 x 0.3 m), the average removal efficiencies of the same species were 71.4±1.3, 75.4±4.9, 67.4±4.3, 72.9±1.3, 83.6±7.6, 89.8±7.4, and 80.9±7.1%, respectively. Adsorption associated with fixation, and ion exchange could be the main treatment mechanisms. COM also has potential as a filtration medium in other treatment unit processes and to treat some other types of wastewater than landfill-leachate. Further, this use of COM could alleviate the burden of disposing of BMW waste, thereby addressing a significant issue in waste management. As the identification of potential failure points in reactive media is crucial, field-scale experiments are suggested to be conducted for further investigation.

Concentration and reduction efficiency of vancomycin-resistant heterotrophic bacteria and vanA and vanB genes in wastewater treatment unit processes

ObjectivesThis study elucidated the distribution and fate of vancomycin (VCM)-resistant heterotrophic bacteria (HTB) and resistance genes, vanA and vanB, during each treatment unit process of a wastewater treatment plant (WWTP). MethodsSeveral bacterial counts as well as copy numbers of vanA and vanB genes were determined in each wastewater and sludge sample. In addition, HTB strains isolated from wastewater and sludge were analyzed for VCM susceptibility. Then, the fate and reduction ratios of each bacterial count, copy number of vanA and vanB genes, and the existence ratio of VCM-resistant HTB strains in the wastewater treatment unit process were evaluated. ResultsVCM-resistant HTB were detected in all wastewater and sludge samples, and their existence ratio decreased along the treatment process (92.9% in influent wastewater to 39.4% in chlorinated water). Notably, most of the HTB isolated from the influent wastewater were resistant to 8.0 µg/mL of VCM, strongly suggesting that a significant number of antibiotic-resistant bacteria are flowing into the WWTP from urban areas through the sewage system. The vanA and vanB genes were also detected in all wastewater and sludge, with high copy numbers (102-104 copies/mL) even in chlorinated water samples. ConclusionsResults revealed that residual VCM-resistant HTB, and resistance genes, which could not be completely removed, were ubiquitously released into the aquatic environment. Furthermore, a high existence ratio of VCM-resistant HTB and high copy numbers of resistance genes were also detected in the sludge, indicating that they are constantly circulating in the WWTP via the returned sludge.

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.

High-Throughput Method for Natural Organic Matter Hydrophobicity Assessment Using an Ionic Liquid-Based Aqueous Two-Phase System.

Hydrophobicity of natural organic matter (NOM) is one of its fundamental properties that influence the environmental fate of pollutants and the performance of many water treatment unit processes. In this study, a high-throughput method was developed for NOM hydrophobicity measurement based on the phase separation technique in the 96-well format. It measures the partition coefficients of NOM (KATPS,IL) in an ionic liquid (IL)-based aqueous two-phase system (ATPS). The ATPS was made of 1-butyl-3-methylimidazole bromide solution and a salt solution containing potassium phosphate monobasic and potassium phosphate dibasic. The partition of NOM in IL-based ATPS is mainly affected by its hydrophobicity. log KATPS,IL linearly correlated with the commonly used NOM hydrophobicity scales, including (O + N)/C, O/C, and aromatic carbons. KATPS,IL provided a more accurate assessment of NOM hydrophobicity than spectroscopic indices. Furthermore, KATPS,IL can predict the organic carbon-water partition coefficients for hydrophobic organic chemical sorption to NOM based on the two-phase system model. The high-throughput KATPS,IL measurement and the two-phase system model can be applied to real surface water samples. Our results suggest that the proposed high-throughput method has great potential to be applied to monitor NOM hydrophobicity for environmental risk assessment and water treatment purposes.

Distribution of Heavy Metals and Their Corresponding Nanoparticles in Different Treatment Unit Processes in the Sewage Treatment Plant

Total heavy metal concentration, heavy metal nanoparticle concentration, particle size, and the removal effect of different treatment unit processes on heavy metals and heavy metal nanoparticles were analyzed in this study. Inductively coupled plasma mass spectrometry (ICP-MS) and single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) were applied in nine treatment units performing continuous wastewater treatment processes in the Chengdu Shuangliu International Airport sewage treatment plant. Results showed that different treatment unit processes had different effects on the removal of different total heavy metal elements, with the effects on Fe being the most significant; Fe was mainly removed in the secondary sedimentation tank at a rate of 98.53%. The removal effects of different heavy metal nanoparticles varied in different treatment unit processes, with the effects of Ni, Pd, and Fe being the most significant. Heavy metal nanoparticles removal varied by treatment unit processes (aeration grit tank, secondary sedimentation tank, and high-efficiency sedimentation tank). The particle size distribution of heavy metal nanoparticles in different treatment unit processes was 23.28-147.83 nm, and different treatment unit processes did not have a significant impact on the particle size of each heavy metal nanoparticle. In addition, pH exhibited a significant negative correlation with Fe and Fe nanoparticles. Excluding Fe and Fe nanoparticles, other heavy metals and their nanoparticles were not significantly related; thus, different processing unit processes exhibited different removal mechanisms for heavy metals and their corresponding nanoparticles.

Removing Iron and Organic Substances from Water over the Course of Its Treatment with the Application of Average and Highly Alkaline Polyaluminium Chlorides

In topic-related literature pertaining to the treatment of water, there is a lack of information on the influence of iron ions in highly basic polyaluminum chlorides on the efficiency of purifying water with increased contents of organic substance. The aim of this work was to determine the changes in the content of organic substances as well as iron compounds in water intended for human consumption following unit treatment processes with particular attention paid to the coagulation process. As coagulants, polyaluminium chloride PAXXL10 with an alkalinity of 70%, as well as polyaluminium chloride PAXXL1911 with an alkalinity of 85% the composition of which also contained iron, were tested. The analysis of the obtained results showed that iron compounds and organic substances were removed to the greatest extent by the coagulation process, which also had a significant influence on the final efficiency of water treatment. The effectiveness of water treatment was determined by the type of tested polyaluminum chloride, which influenced the formation of iron-organic complexes. The reason behind the formation of colored iron-organic complexes during coagulation using PAXXL1911 coagulant was the high pH (approx. 8), at which the functional groups of organic substances, due to their dissociation, are more reactive in relation to iron, and possibly the fact of introducing additional iron ions along with the coagulant.

Optimal selection of “zero liquid discharge” (ZLD) system using “analytical hierarchy process” (AHP) and “grey relational analysis” (GRA)

This article specifically presents three different zero liquid discharge (ZLD) options as “Desalination of industrial wastewater and associated rejects management” and deals with optimal selection of ZLD system using “analytical hierarchy process” and “grey relation analysis” (GRA). Commercially available ZLD systems, which differ from each other in some way or the other, were assessed for various factors. Hierarchy among the three factors, viz. economic, technical, and administrative criteria, was considered to arrive at the best treatment option. Each criterion again involved hierarchy of indices. The most suitable ZLD option was arrived at in two ways: 1) by comparing the commercially available treatment options and 2) by deriving the most suitable option based on the maximum beneficial unit operation and treatment process among all the options. A ZLD treatment system based on the combination of unit operation and processes of different treatment options was recommended since it provided maximum benefits. An assessment of annual expenditure on operation and maintenance of existing ZLD system revealed that there is an emergent need to develop more cost-effective techniques to make them environmentally and economically sustainable.

Human Health, Economic and Environmental Assessment of Onsite Non-Potable Water Reuse Systems for a Large, Mixed-Use Urban Building.

Onsite non-potable reuse (NPR) is being increasingly considered as a viable option to address water scarcity and infrastructure challenges, particularly at the building scale. However, there are a range of possible treatment technologies, source water options, and treatment system sizes, each with its unique costs and benefits. While demonstration projects are proving that these systems can be technologically feasible and protective of public health, little guidance exists for identifying systems that balance public health protection with environmental and economic performance. This study uses quantitative microbial risk assessment, life cycle assessment and life cycle cost analysis to characterize the human health, environmental and economic aspects of onsite NPR systems. Treatment trains for both mixed wastewater and source-separated graywater were modeled using a core biological process—an aerobic membrane bioreactor (AeMBR), an anaerobic membrane bioreactor (AnMBR) or recirculating vertical flow wetland (RVFW)—and additional treatment and disinfection unit processes sufficient to meet current health-based NPR guidelines. Results show that the graywater AeMBR system designed to provide 100% of onsite non-potable demand results in the lowest impacts across most environmental and human health metrics considered but costs more than the mixed-wastewater version due to the need for a separate collection system. The use of multiple metrics also allows for identification of weaknesses in systems that lead to burden shifting. For example, although the RVFW process requires less energy than the AeMBR process, the RVFW system is more environmentally impactful and costly when considering the additional unit processes required to protect human health. Similarly, we show that incorporation of thermal recovery units to reduce hot water energy consumption can offset some environmental impacts but result in increases to others, including cumulative energy demand. Results demonstrate the need for additional data on the pathogen treatment performance of NPR systems to inform NPR health guidance.

Trihalomethane precursor reactivity changes in drinking water treatment unit processes during a storm event.

Source water quality can significantly impact the efficacy of water treatment unit processes and the formation of chlorinated and brominated trihalomethanes (THMs). Current water treatment plant performance models may not accurately capture how source water quality variations, such as organic matter variability, can impact treatment unit processes. To investigate these impacts, a field study was conducted wherein water samples were collected along the treatment train for 72 hours during a storm event. Systematic sampling and detailed analyses of water quality parameters, including non-purgeable organic carbon (NPOC), UV absorbance, and THM concentrations, as well as chlorine spiking experiments, reveal how the THM formation potential changes in response to treatment unit processes. Results show that the NPOC remaining after treatment has an increased reactivity towards forming THMs, and that brominated THMs form more readily than chlorinated counterparts in a competitive reaction. Thus both the reactivity and quantity of THM precursors must be considered to maintain compliance with drinking water standards, a finding that should be incorporated into the development of model-assisted treatment operation and optimization. Advanced granular activated carbon (GAC) treatment beyond conventional coagulation-flocculation-sedimentation processes may also be necessary to remove the surge loading of THM-formation precursors during a storm event.

Optimising wastewater treatment solutions for the removal of contaminants of emerging concern (CECs): a case study for application in India

Abstract The aim of this study was to produce optimal wastewater treatment solutions to calculate the removal of different contaminants of emerging concern (CECs) found in developing countries. A new methodology was developed for a decision support tool (WaStewater Decision support OptiMiser, WiSDOM), which focuses on producing treatment solutions suited to treating water for reuse to Indian Water Quality Standards. WiSDOM-CEC analyses the removal of CECs through different treatment solutions and was also used to evaluate the performance of each treatment train solution in terms of the removal of conventional pollutants using multi-objective optimisation and multi-criteria decision analysis. Information was collected on different CECs across different regions of India, and the removal of 18 different CECs through 42 wastewater treatment unit processes for five different regions of India was analysed. Comparisons between similar categories of CECs, such as non-steroidal anti-inflammatory, showed that emerging contaminants all react differently with individual treatment options. For example, the removal of ibuprofen (IBP) and naproxen (NPX) varied from >80% and 0%, respectively, for a solution in Karnataka involving sedimentation, submerged aerated filter, ultrafiltration and nanofiltration. In Tamil Nadu, results ranged from 36.8% to 72% for diclofenac, 10.7% to 66.5% for IBP, and 0% for NPX.

Evaluating the fate of bacterial indicators, viral indicators, and viruses in water resource recovery facilities

A year‐long sampling campaign at nine water resource recovery facilities (WRRFs) was conducted to assess the treatability and fate of bacterial indicators, viral indicators, and viruses. Influent concentrations of viral indicators (male‐specific and somatic coliphages) and bacterial indicators (Escherichia coli and enterococci) remained relatively constant, typically varying by one order of magnitude over the course of the year. Annual average bacterial indicator reduction ranged from 4.0 to 6.7 logs, and annual average viral indicator reduction ranged from 1.6 to 5.4 logs. Bacterial and viral indicator reduction depended on the WRRF's treatment processes, and bacterial indicator reduction was greater than viral indicator reduction for many processes. Viral reduction (adenovirus 41, norovirus GI, and norovirus GII) was more similar to viral indicator reduction than bacterial indicator reduction. Overall, this work suggests that viral indicator reduction in WRRFs is variable and depends on specific unit processes. Moreover, for the same unit treatment process, viral indicator reduction and bacterial indicator reduction can vary.Practitioner points A year‐long sampling campaign was conducted at nine water resource recovery facilities (WRRFs).The treatability and fate of bacterial indicators, viral indicators, and viruses were assessed.Viral indicator reduction in WRRFs is variable and depends on specific unit processes.For the same unit treatment process, viral indicator reduction and bacterial indicator reduction can vary.

The effect of water treatment unit processes on cyanobacterial trichome integrity

Many toxic and/or noxious cyanobacteria appear in nature with a filamentous, stacked cell arrangement called trichomes. Although water treatment can be optimized to keep cyanobacterial cells intact and avoid the release of toxic and/or noxious compounds, many physical and chemical stresses encountered during the treatment process may result in trichome truncation, decreasing treatment efficiency by allowing single cells or short trichomes to reach the product water. This makes it possible for harmful/noxious compounds as well as organic matter to enter the distribution system. Investigations in a pilot and three full-scale water treatment plants were carried out in order to elucidate the degree of trichome truncation across different unit processes. It was found that genera (Pseudanabaena, Planktolyngbya) with short trichomes (<10–12 cells per trichome), are hardly affected by the unit processes (loss of one to four cells respectively), while genera (Planktothrix, Geitlerinema, Dolichospermum) with longer trichomes (30+ cells per trichome) suffer from high degrees of truncation (up to 63, 30, and 56 cells per trichome respectively). The presence of a rigid sheath and/or mucilaginous layer appears to offer some protection from truncation. It was observed that certain unit processes alter the sensitivity or resilience of trichomes to disruption by physical stress. Some genera (Planktothrix, Geitlerinema) were sensitive to pre-oxidation making them more susceptible to shear stress, while Dolichospermum sp. appears more robust after pre-oxidation. While the potential of toxicogenic genera breaking through into the product water is a real danger, in the current study no toxicogenic cyanobacteria were observed. This work stresses the need for plant operators to study the incoming cyanobacterial composition in the raw water in order to adjust treatment parameters and thus limit the potential of toxic/noxious compound breakthrough.

Potable Water Reuse: What Are the Microbiological Risks?

With the increasing interest in recycling water for potable reuse purposes, it is important to understand the microbial risks associated with potable reuse. This review focuses on potable reuse systems that use high-level treatment and de facto reuse scenarios that include a quantifiable wastewater effluent component. In this article, we summarize the published human health studies related to potable reuse, including both epidemiology studies and quantitative microbial risk assessments (QMRA). Overall, there have been relatively few health-based studies evaluating the microbial risks associated with potable reuse. Several microbial risk assessments focused on risks associated with unplanned (or de facto) reuse, while others evaluated planned potable reuse, such as indirect potable reuse (IPR) or direct potable reuse (DPR). The reported QMRA-based risks for planned potable reuse varied substantially, indicating there is a need for risk assessors to use consistent input parameters and transparent assumptions, so that risk results are easily translated across studies. However, the current results overall indicate that predicted risks associated with planned potable reuse scenarios may be lower than those for de facto reuse scenarios. Overall, there is a clear need to carefully consider water treatment train choices when wastewater is a component of the drinking water supply (whether de facto, IPR, or DPR). More data from full-scale water treatment facilities would be helpful to quantify levels of viruses in raw sewage and reductions across unit treatment processes for both culturable and molecular detection methods.

An Implementation of a Decision Support Tool to Assess Treatment of Emerging Contaminants in India

Emerging contaminants have been increasingly studied over the past decade to improve the understanding of their fate, occurrence and toxicological effects on the environment and human health. Originally wastewater treatment plants were not designed to remove these pollutants of emerging concern. However, research is now focusing on determining which existing treatment unit processes are suited to their removal. This research sets out to determine suitable treatment options for thirty nine emerging contaminants including various Pharmaceuticals and Personal Care products. The treatment options used in this study are taken from a developed decision support tool (WiSDOM) which formulates wastewater trains/packages for treatment of wastewater in India. The tool also evaluates the performance of each optimal solution in terms of removal of conventional pollutants (such as biochemical oxygen demand, chemical oxygen demand, total nitrogen, total phosphorous, faecal coliform etc.), using multi-objective genetic algorithms and multi-criteria decision analysis. An Excel Spreadsheet Program (ESP) was developed as an add-on to the tool, allowing the ESP to take an initial concentration of any of the thirty nine emerging contaminant and pass it through the treatment trains (generated/selected by the WiSDOM tool) to determine the removal efficiency. Three scenarios were developed to analyse the removal of emerging contaminants in India. The scenarios were designed to capture the influence of different socio-economic contexts and wastewater characteristics on the treatment technology selection. The tool generated results suggest that the use of constructed wetlands can remove a large proportion of emerging contaminants, resulting in low energy requirements and operational costs and wildlife habitats. However, the land requirement for this process is not always suited to urban areas in India. Advanced oxidation processes were also efficient at removing emerging contaminants. However, the energy requirements for this process were high. Emerging contaminants have different physical and chemical properties; therefore, future evaluations of each chemical should be monitored separately to generate suitable technologies suited to optimal removal.

Direct potable reuse microbial risk assessment methodology: Sensitivity analysis and application to State log credit allocations

Understanding pathogen risks is a critically important consideration in the design of water treatment, particularly for potable reuse projects. As an extension to our published microbial risk assessment methodology to estimate infection risks associated with Direct Potable Reuse (DPR) treatment train unit process combinations, herein, we (1) provide an updated compilation of pathogen density data in raw wastewater and dose-response models; (2) conduct a series of sensitivity analyses to consider potential risk implications using updated data; (3) evaluate the risks associated with log credit allocations in the United States; and (4) identify reference pathogen reductions needed to consistently meet currently applied benchmark risk levels. Sensitivity analyses illustrated changes in cumulative annual risks estimates, the significance of which depends on the pathogen group driving the risk for a given treatment train. For example, updates to norovirus (NoV) raw wastewater values and use of a NoV dose-response approach, capturing the full range of uncertainty, increased risks associated with one of the treatment trains evaluated, but not the other. Additionally, compared to traditional log-credit allocation approaches, our results indicate that the risk methodology provides more nuanced information about how consistently public health benchmarks are achieved. Our results indicate that viruses need to be reduced by 14 logs or more to consistently achieve currently applied benchmark levels of protection associated with DPR. The refined methodology, updated model inputs, and log credit allocation comparisons will be useful to regulators considering DPR projects and design engineers as they consider which unit treatment processes should be employed for particular projects.

Evaluation of virus reduction efficiency in wastewater treatment unit processes as a credit value in the multiple-barrier system for wastewater reclamation and reuse.

The virus reduction efficiency of each unit process is commonly determined based on the ratio of virus concentration in influent to that in effluent of a unit, but the virus concentration in wastewater has often fallen below the analytical quantification limit, which does not allow us to calculate the concentration ratio at each sampling event. In this study, left-censored datasets of norovirus (genogroup I and II), and adenovirus were used to calculate the virus reduction efficiency in unit processes of secondary biological treatment and chlorine disinfection. Virus concentration in influent, effluent from the secondary treatment, and chlorine-disinfected effluent of four municipal wastewater treatment plants were analyzed by a quantitative polymerase chain reaction (PCR) approach, and the probabilistic distributions of log reduction (LR) were estimated by a Bayesian estimation algorithm. The mean values of LR in the secondary treatment units ranged from 0.9 and 2.2, whereas those in the free chlorine disinfection units were from -0.1 and 0.5. The LR value in the secondary treatment was virus type and unit process dependent, which raised the importance for accumulating the data of virus LR values applicable to the multiple-barrier system, which is a global concept of microbial risk management in wastewater reclamation and reuse.

Evaluation of microbiological risks associated with direct potable reuse

This work evaluates the potential microbial risks associated with various direct potable reuse (DPR) treatment train combinations for recycled water. The assessment methodology leverages readily available peer-reviewed pathogen density and treatment process removal data and extends a previously published statistical approach. The results illustrate clear quantitative human health-based advantages for DPR projects in which product water is introduced into the raw water supply upstream of a conventional drinking water treatment facility, compared to those in which product water is introduced directly into a potable water supply distribution system. The results also indicate that a single day can drive annual risks, highlighting the need for robust and reliable on-line monitoring of unit treatment processes within DPR facilities. The methodology is adaptable to other DPR treatment trains and could be iteratively refined as additional data become available. This work will be useful to federal and state regulators considering DPR as source water, state and local decision makers as they consider whether to permit a particular DPR project, and design engineers as they consider which unit treatment processes should be employed for particular projects.

SUSTAINABLE MANAGEMENT OF WATER SUPPLY NETWORKS IN AMAWBIA, ANAMBRA STATE, NIGERIA

This work addresses the sustainable management of water supply given one or more sources of water supply for the Amawbia Water Scheme which is under the Awka Water Scheme of the Anambra State Water Corporation, Awka. The viable cost for water supply and distribution in the study area shall be determined which takes into account the annual operation and maintenance costs.This shall help the Anambra State Water Corporation, Awka, the responsible water agencyfor this water scheme to stay in business as it faces the challenges of competing water vendors in Amawbia and environs. The annual costs for the operation and maintenance is forty two million, four hundred thousand naira only (N42.4m) for the unit treatment processes of sedimentation, coagulation and flocculation, filtration, metals removal and disinfection. The accruable annual revenue which is one hundred and twenty six million, seven hundred and twenty thousand naira only (N126.72m) shows that the water scheme is sustainable and viable if properly managed by the responsible water agency.

정수처리 공정에서 잔류의약물질 제어 효율 평가

In the present study, we evaluated the efficiency of the drinking water treatment unit processes controlled by targeting high pharmaceutical compounds that are likely to be released into the water supply. In the coagulation process, the removal rate of sulfonamide, an antibiotic, amounted to 22.6~42.1 %, that of naproxen to 28.2 %, and that of acetaminophen to 20 %. Trimethoprim has demonstrated a low removal rate (4.4 %), while the removal rate of erythromycin was 2.4 %; aspirin was not removed at all. When applying a mixture of chlorination and the coagulation process, the removal rate was increased with increasing the chlorine dosage. When the chlorine injection with the concentration of 3 mg/L was applied, sulfonamide antibiotics, acetaminophen and naproxen, were completely removed. Trimethoprim exhibited a high removal efficiency of ca. 98%, while the removal efficiency of erythromycin was about 55 %; at the same time, aspirin showed a lower removal ratio (ca. 10 %). When applying the powdered activated carbon adsorption process, the removal rate was increased with increase of the concentration of the powder activated carbon injection. Sulfonamide antibiotics showed about 18~50 % removal efficiency in the 1 mg/L, the removal rate was increased by at least 80 % in 25 mg/L. The evaluation results of the titration injection concentration of chlorine treatment and adsorption, coagulation process for the efficient processing of the remaining pharmaceutical compounds in the water treatment process, when applying the chlorine 3 mg/L, powdered activated carbon 10 mg/L and coagulant 15 mg/L were removed more than 90 %. 요 약: 상수원으로 유출될 가능성이 높은 잔류의약물질 대상으로 정수처리공정의 단위 공정별 잔류의 약물질 제어 효율을 평가하였다. 응집 공정에서는 Sulfonamide계 항생제는 22.6~42.1 % 제거 되었으며, Naproxen 28.2 %, Acetaminophen 20 %가 제거되었다. Trimethoprim은 4.4 %, Erythromycin은 2.4 %로 낮 ★ Corresponding author Phone : +82-(0)62-609-6334 Fax : +82-(0)62-609-6319 E-mail : hjseo@korea.kr This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons. org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Evaluation on the removal efficiency of pharmaceutical compounds in conventional drinking water treatment processes 127 Vol. 29, No. 3, 2016 은 제거율을 보여 주었으며, Aspirin은 전혀 제거되지 않았다. 염소처리와 응집 혼합 공정을 적용하였을 때, 염소 주입량이 증가할수록 제거율이 증가되었다. 염소주입농도 3 mg/L일 때 Sulfonamide계 항생제, Acetaminophen, Naproxen은 100 %, Trimethoprim은 약 98%로 높은 제거 효율을 나타내었으며 Erythromycin 은 약 55 %, Aspirin은 약 10 %로 낮은 제거율을 보여 주었다. 분말활성탄 흡착 공정을 적용하였을 때, 분말활성탄 주입 농도가 증가할수록 제거율이 증가되었다. Sulfonamide계 항생제의 경우 1 mg/L에서 약 18~50 % 제거율을 보였으며, 25 mg/L에서는 약 80 % 이상으로 제거율이 증가하였다. 정수처리 공정에 서 잔류의약물질의 효율적인 처리를 위한 염소처리와 흡착, 응집 공정의 적정 주입농도를 평가한 결과 염소 3 mg/L, 분말활성탄 10 mg/L, 응집제 15 mg/L을 적용했을 때 약 90 % 이상이 제거되었다.

Comparative study of ground water treatment plants sludges to remove phosphorous from wastewater

Alum- and iron-based sludge obtained from water treatment plant produced during a unit treatment process (coagulation and flocculation) have been widely tested as a low-cost adsorbent to remove phosphorous (P) from wastewater. However, the effectiveness of iron-based sludge generated from the oxidation of iron which naturally occurs in the ground water has not been investigated. Moreover, influences of dominant metals ions comprised in the treatment plants sludges on P adsorption capacity and rate from wastewater are not yet known. This study, therefore, employed four different groundwater treatment plants sludges iron-based (from the oxidation of iron) and alum-based (from coagulation and flocculation process) to determine their P adsorption capacities and adsorption rates from the synthetic wastewater (SWW) and secondary effluent wastewater (SEWW). Although metals ions concentrations were the highest in the iron-based sludge amongst the sludge used in this study, it appeared to have the lowest P adsorption capacity and adsorption rate. A good correlation between aluminium to iron mass ratio and adsorption capacity for both types of waters were noted. However, a poor relation between aluminium to iron mass ratio and adsorption rates for the SEWW was observed. Further, the tested sludges were found to have a better P removal efficiency and adsorption capacity from the SEWW than from the SWW. Thus, this study demonstrates the ground water treatment plants sludges could be a low cost and effective adsorbent in removing P from wastewater.