Existing Treatment Systems Research Articles

Effects of surfactants, ion valency and solution temperature on PFAS rejection in commercial reverse osmosis (RO) and nanofiltration (NF) processes

Per- and polyfluoroalkyl substances (PFAS) have garnered attention as a pressing environmental issue due to their enduring presence and suspected adverse health effects. This study assessed the rejection or removal efficacy of PFAS by commercial reverse osmosis (RO) and nanofiltration (NF) membranes and examined the impacts of surfactants, ion valency and solution temperature that are inadequately explored. The results reveal that the presence of cationic surfactants such as cetyltrimethylammonium bromide (CTAB) increased the rejection of two selected PFAS compounds, perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA), by binding with negatively charged PFAS and preventing them from passing through membrane pores via size exclusion, whereas the presence of anionic surfactants such as sodium dodecyl sulfate (SDS) increased the PFAS rejection because the increased electrostatic repulsion prevented PFAS from approaching and adsorbing onto the membrane surface. Moreover, aqueous ions (e.g., Al3+ and PO43−) with higher ion valency enabled higher rejection of PFOA and PFBA through increased effective molecular size and increased electronegativity. Finally, only high solution temperature at 45 °C significantly reduced PFAS rejection efficiency because of the thermally expanded membrane pores and thus the increased leakage of PFAS. Overall, this research provides valuable insights into the various factors impacting PFAS rejection in commercial RO and NF processes. These findings are crucial for developing efficient PFAS removal methods and optimizing existing treatment systems, thereby contributing significantly to the ongoing efforts to combat PFAS contamination.

Understanding the spread of antibiotic resistance in vegetables cultivated with sewage sludge: implications for food safety and human health

The conventional practice of using sewage treatment plant (STP) derived sludge as a fertilizer poses significant negative impacts on agroecosystems. Since sludge has diverse contaminants, including heavy metals (HMs), antibiotics (ABs) and antibiotic resistance genes (ARGs), its application in the agricultural fields contaminates the food and hence causes human health risks via the food chain. The transfer of ABs and ARGs from sludge to soil and then to plants can influence the development of antibiotic resistance (AR) in plant endophytes, and leads to variations in their characteristics. In a pot experiment, vegetable carrot (Daucus carota) and spinach (Spinacia oleracea) were amended with sludge samples from three sewage treatment plants (STPs) with varying treatment capacities and both above and below-ground parts of the plants were analysed for the presence of specific ABs (amoxicillin, azithromycin, chloramphenicol, ciprofloxacin, tetracycline), ARGs (blaCTX-M, blaGES, blaNDM, ermF, qnrS, Sul1), and mobile genetic elements (MGEs) (intl1, IS26). Among the characterized culturable endophytic bacteria (EB), 22 exhibited resistance to various antibiotics (highest against ampicillin, ciprofloxacin, chloramphenicol) and heavy metals (highest against lead, nickel, and chromium). Most importantly, seven multiple antibiotic-resistant endophytic bacteria (MAREB) exhibited resistance to all tested heavy metals (HMs). Additionally, all MAREB tested positive for biofilm production, and a notable proportion (72.72%) of these endophytes displayed mobility, with strong auto-aggregation ranging from 16.67 to 92.61%. The biofilm formation dynamics among these MAREB exhibited a Gaussian distribution pattern, increasing with higher antibiotic concentrations. Notably, five MAREB demonstrated survival at clarithromycin concentrations up to 150 µg ml−1. The study revealed the presence of ABs (µg kg−1) and ARGs (copies kg−1) in all parts of both vegetables, ranging from 2.87 to 314.88 and 1 × 105 to 3.2 × 1010, respectively. MAREB displayed various advantageous features to support plant growth under different stress conditions. Moreover, 51.09% of the identified EBs were reported as both plant and human-associated pathogens, and 9.09% were solely human pathogens. Transfer factor (TF), translocation factor (TLF), and bioconcentration factor (BCF) values were correlated with higher ABs and ARGs abundance in the root and shoot compartments of both vegetables. The risk assessment for ABs and ARGs highlighted children are particularly vulnerable to prolonged adverse health risks from consuming these vegetables. Therefore, this research is imperative for understanding the co-selection mechanisms, the need for improvement of the existing treatment systems in contaminants removal, and the evaluation of the presence of ABs and ARGs in sludge before its application in agricultural fields.

Wastewater treatment from a science faculty during the COVID-19 pandemic by using ammonium-oxidising and heterotrophic bacteria

During and after the pandemic caused by the SARS-CoV-2 virus, the use of personal care products and disinfectants increased in universities worldwide. Among these, quaternary ammonium-based products stand out; these compounds and their intermediates caused substantial changes in the chemical composition of the wastewater produced by these institutions. For this reason, improvements and environmentally sustainable biological alternatives were introduced in the existing treatment systems so that these institutions could continue their research and teaching activities. For this reason, the objective of this study was to develop an improved culture medium to cultivate ammonium oxidising bacteria (AOB) to increase the biomass and use them in the treatment of wastewater produced in a faculty of sciences in Bogotá, D.C., Colombia. A Plackett Burman Experimental Design (PBED) and growth curves served for oligotrophic culture medium, and production conditions improved for the AOB. Finally, these bacteria were used with total heterotrophic bacteria (THB) for wastewater treatment in a pilot plant. Modification of base ammonium broth and culture conditions (6607 mg L−1 of (NH4)2SO4, 84 mg L−1 CaCO3, 40 mg L−1 MgSO4·7H2O, 40 mg L−1 CaCl2·2H2O and 200 mg L−1 KH2PO4, 10% (w/v) inoculum, no copper addition, pH 7.0 ± 0.2, 200 r.p.m., 30 days) favoured the growth of Nitrosomonas europea, Nitrosococcus oceani, and Nitrosospira multiformis with values of 8.23 ± 1.9, 7.56 ± 0.7 and 4.2 ± 0.4 Log10 CFU mL−1, respectively. NO2− production was 0.396 ± 0.0264, 0.247 ± 0.013 and 0.185 ± 0.003 mg L−1 for Nitrosomonas europea, Nitrosococcus oceani and Nitrosospira multiformis. After the 5-day wastewater treatment (WW) by co-inoculating the three studied bacteria in the wastewater (with their self-microorganisms), the concentrations of AOB and THB were 5.92 and 9.3 Log10 CFU mL−1, respectively. These values were related to the oxidative decrease of Chemical Oxygen Demand (COD), (39.5 mg L−1), Ammonium ion (NH4+), (6.5 mg L−1) Nitrite (NO2−), (2.0 mg L−1) and Nitrate (NO3−), (1.5 mg L−1), respectively in the five days of treatment. It was concluded, with the improvement of a culture medium and production conditions for three AOB through biotechnological strategies at the laboratory scale, being a promising alternative to bio-augment of the biomass of the studied bacteria under controlled conditions that allow the aerobic removal of COD and nitrogen cycle intermediates present in the studied wastewater.

Sanitary Sewerage Master Plan for the Sustainable Use of Wastewater on a University Campus

Wastewater collection, transport, and treatment systems are essential to ensure human and environmental well-being. The Escuela Superior Politécnica del Litoral (ESPOL), has been implementing various sanitary sewerage systems; however, population growth has given rise to discussion on the installed capacity versus the necessary capacity for the future population in the sustainable management of water resources. Therefore, this study aimed to develop a sanitary sewerage master plan by analysing the existing situation and applying technical criteria for the sustainable use of wastewater on a university campus. The methodology consisted of (i) evaluation and diagnosis of the area studied through data collection and processing, (ii) design of the sanitary sewerage system considering area-expansion zones, and (iii) SWOT analysis of a proposal to enhance wastewater transport and treatment systems. The proposal contemplates designing a sanitary sewer system that will manage the collection, transport, and treatment of wastewater over 15 years for 5667 inhabitants located in three expansion zones with occupation periods of 5, 10, and 15 years. The sewerage system comprises a pipe network 1.19 km long and 200 mm in diameter, transporting 12.37 L/s of wastewater generated to two treatment systems that guarantee efficient depuration and subsequent reuse. This design was complemented by a SWOT analysis of the existing sanitation system developed by experts in the area, which included optimising existing treatment systems and reusing wastewater for irrigation of green areas as tertiary treatment within the circular economy. The methodology used in the study allows us to offer a tool for efficiently managing wastewater on a university campus, guaranteeing human well-being, and promoting the circular economy of water.

Cognitive Wearable Robotics for Autism Perception Enhancement

Autism spectrum disorder (ASD) is a serious hazard to the physical and mental health of children, which limits the social activities of patients throughout their lives and places a heavy burden on families and society. The developments of communication techniques and artificial intelligence (AI) have provided new potential methods for the treatment of autism. The existing treatment systems based on AI for children with ASD focus on detecting health status and developing social skills. However, the contradiction between the terminal interaction capability and availability cannot meet the needs for real application scenarios. At the same time, the lack of diverse data cannot provide individualized care for autistic children. To explore this robot-based approach, a novel AI-based first-view-robot architecture is proposed in this article. By providing care from the first-person perspective, the proposed wearable robot overcomes the difficulty of the absence of cognitive ability in the third-view of traditional robotics and improves the social interaction ability of children with ASD. The first-view-robot architecture meets the requirements of dynamic, individualized, and highly immersed interaction services for autistic children. First, the multi-modal and multi-scene data collection processes of standard, static, and dynamic datasets are introduced in detail. Then, to comprehensively evaluate the learning ability of children with ASD through mental states and external performances, a learning assessment model with emotion correction is proposed. Besides, a wearable robot-assisted environment perception and expression enhancement mechanism for children with ASD is realized by reinforcement learning, which can be adapted to interactive environments with optimal action policies. An interactive testbed for children with ASD treatments is demonstrated and experimental cases for test subjects are presented. Last, three open issues are discussed from data processing, robot designing, and service responding perspectives.

Treatment of drug residues (emerging contaminants) in hospital effluent by the combination of biological and physiochemical treatment process: a review

Treatment of drug residues (emerging contaminants) in hospital effluent by the combination of biological and physiochemical treatment process: a review

Recent technologies for nutrient removal and recovery from wastewaters: A review

Water scarcity and its pollution has become a concern in recent times. The disposal of nutrient-rich (nitrogen and phosphorous) wastewater is also one of the main cause of water pollution through eutrophication, reduced dissolved oxygen that poses threat to aquatic ecosystems. As a result, nutrient removal has become a mandate apart from the removal of organics. However, the removal of nutrients from sewage is a challenging task. Conversely, conventional biological treatment processes provide little relief in nutrient removal. The treated effluents from conventional biological processes do not achieve the stringent nutrient removal disposal standard limits and become primary cause of pollution in the receiving water bodies. This has stressed upon the need for eco-friendly, low-energy and cost-efficient nutrient removal treatment technologies. Various biological treatment combinations or variants are in use for the efficient removal of nutrients. The biological processes in itself or in combination with chemical processes are preferred over technologies based solely on physico-chemical processes for its treatment performance at lower cost. This review summarizes the existing treatment processes and their possible up-gradation with the aim to accomplish the marked effluent standards for the nutrients. The concept of conventional systems and advanced systems for nutrients (nitrogen and phosphorous) removal which are already developed or under development are deeply discussed. Further, the challenges of each treatment systems are abridged. Finally, the possible suggestions for the modification/retrofitting of existing treatment systems for achieving stringent disposal standards are pointed out.

Occurrence and removal of chemicals of emerging concern in wastewater treatment plants and their impact on receiving water systems

Wastewater treatment plants (WWTPs) are considered the main sources of chemicals of emerging concern (CECs) in aquatic environments, and can negatively impact aquatic ecosystems. In this study, WWTP influent, effluent, and sludge, and upstream and downstream waters from the WWTP recipient were investigated at 15 locations for a total of 164 CECs, including pharmaceuticals, personal care products, industrial chemicals, per- and polyfluoroalkyl substances (PFASs), and pesticides. In addition, zebrafish (Danio rerio) embryo toxicity tests (ZFET) were applied to WWTP influent and effluent, and upstream and downstream waters from WWTP recipients. A total of 119 CECs were detected in at least one sample, mean concentrations ranging from 0.11 ng/L (propylparaben) to 64,000 ng/L (caffeine), in wastewater samples and from 0.44 ng/L (ciprofloxacin) to 19,000 ng/L (metformin) in surface water samples. Large variations of CEC concentrations were found between the selected WWTPs, which can be explained by differences in CEC composition in influent water and WWTP treatment process. The sludge-water partitioning coefficient (Kd) of CECs showed a significant linear correlation to octanol/water partition coefficient (KOW) (p < 0.001), and thus could be used for predicting their fate in the aqueous and solid phase. The ΣCEC concentrations in WWTPs declined by on average 60%, based on comparisons of WWTP influent and effluent concentrations. The high concentrations of CECs in WWTP effluent resulted in, on average, 50% higher concentrations of CECs in water downstream of WWTPs compared with upstream. Some WWTP samples showed toxicity in ZFET compared with the respective control group, but no individual CECs or groups of CECs could explain this toxicity. These results could provide a theoretical basis for optimization of existing treatment systems of different designs, and could significantly contribute to protecting recipient waters.

Viruses in wastewater: occurrence, abundance and detection methods

This paper presents an updated and comprehensive review on the different methods used for detection and quantification of viruses in wastewater treatment systems. The analysis of viability of viruses in wastewater and sludge is another thrust of this review.Recent studies have mostly focused on determining the abundance and diversity of viruses in wastewater influents, in samples from primary, secondary, and tertiary treatment stages, and in final effluents. A few studies have also examined the occurrence and diversity of viruses in raw and digested sludge samples. Recent efforts to improve efficiency of virus detection and quantification methods in the complex wastewater and sludge matrices are highlighted in this review.A summary and a detailed comparison of the pre-treatment methods that have been utilized for wastewater and sludge samples are also presented. The role of metagenomics or sequencing analysis in monitoring wastewater systems to predict disease outbreaks, to conduct public health surveillance, to assess the efficiency of existing treatment systems in virus removal, and to re-evaluate current regulations regarding pathogenic viruses in wastewater is discussed in this paper. Challenges and future perspectives in the detection of viruses, including emerging and newly emerged viruses such as the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in wastewater systems are discussed in this review.

Study of the Synergistic Effect of Some Antibiotics and Aqueous Extract of Hibiscus sabdariffa Plant against Salmonella typhi

The rising issue of drug-resistant bacterial species has resulted in the failure of existing treatment systems for Salmonella typhi. Lately, a recent treatment strategy was sophisticated to control the problem by using natural products with antibiotics to promote the effectiveness of treatment. The aim of this research was to test the inhibitory efficacy of Hibiscus sabdariffa calyxes extract toward S. typhi without, and with the following antibiotics, ciprofloxacin, azithromycin, chloramphenicol, ampicillin, amoxicillin, trimethoprim, coftriaxon, and norfloxacin, which were tested by the well diffusion method and disks propagation method, respectively, using Muller Hinton agar. H. sabdariffa cups (35 grams) were taken and placed in 250 mL of boiling water for 30 minutes. A series of concentrations of the aqueous extract were then made by dilution method (50, 100, 150, 250, and 500 mg/mL). The results showed that the extract of hibiscus had an inhibitory effect on the studied bacteria at each concentration 150, 250, and 500 mg/mL with diameter of inhibition 25, 27, 18 mm, respectively. The antibiotic susceptibility test was done, where the antibiotics ciprofloxacin, norfloxacin, and ceftriaxon showed areas of inhibition of diameters 25, 31, and 32 mm, respectively. The synergistic effect was then tested by mixing the aquatic extract of H. sabdariffa with the antibiotics; the results showed an increase in the diameters of the inhibition zones compared with the diameters in the use of each of them separately. The highest inhibitory zones were observed with concentration (150 mg/mL) of the extract with ciprofloxacin, and the lowest inhibitory area was recorded at (100 mg/mL) of extract with chloramphenicol. The lowest inhibitory concentration (250 mg/mL) and the lowest killer concentration (500 mg/mL) were also identified.

A review of acid rock drainage, seasonal flux of discharge and metal concentrations, and passive treatment system limitations

ABSTRACT The efficacy of passive treatment systems for remediating acid rock drainage can be limited by the seasonal flux of discharge and metal concentrations that may not have been considered during treatment design. A review of passive treatment options for acid rock drainage indicates reduced efficacy due to seasonal periods of increased drainage and metal concentrations that lead to mineral precipitation, surface passivation, and flow bypass. In select cases, passive treatment systems prematurely failed due to seasonal flux or experienced substantially reduced treatment efficacy and life of the system. Complimentary systems are needed to minimise impacts from seasonal flux of drainage and metal concentrations to improve treatment efficacy and preserve the life of a multi-component system or a downstream primary system. Multi-component systems are possible with integration of existing treatment systems and design of new treatment options to tailor treatment to site specifications.

Analysis and Feasibility of Measures to Minimize the Impact of Acid Mine Waters Discharged by Abandoned Copper-Sulphide Mines on Hydrosphere of the Tagil River

Mass closure of copper-sulphide mining sites both in the Sverdlovsk Region and worldwide resulted in the emergence of environmental challenges. One of such challenges is generation and discharge of acid mine waters. Manmade and natural factors have their impact on chemical composition of mine waters due to activation of sulphides oxidation processes taking place in disturbed rock mass and mines. Concentrations of components in treated mine waters are much higher than MAC (dozens and hundreds of times for iron, copper and zinc). That results in pollution of hydrosphere which goes on for decades and spreads over large distances along rivers. Quite a few reasons cause environmental degradation of hydrosphere in old industrial districts. These are baseline amounts of metals in the hydrosphere, low rates of self-rehabilitation of dead pits, high amounts of acid waters, high amounts of contaminants in mine waters, imperfection of treatment systems. Given the demand of mine waters treatment over decades, improvement of existing treatment systems and implementation of new technologies are required.

Comparison of two mechanical pre-treatment systems for impurities reduction of source-separated biowaste

The treatment of source-separated biowaste is still a challenge due to its high proportion of impurities. Biowaste bins are intended exclusively for the collection of biodegradable matter, such as food, kitchen and garden waste. However, plastics, metals, glass and textiles are also found in biowaste bins. If not properly removed, these impurities cause problems to the treatment facility and depreciate the quality of the final product, when the biowaste is converted to compost. There is ongoing discussion whether the existing treatment systems are able to remove impurities, especially plastics, from biowaste thoroughly enough to ensure that the produced compost complies with state regulations. In this work, two wet mechanical pre-treatment systems were tested for their efficiency to remove impurities. The first system consisted of a screw mill, a star screen, and a food unpacking machine (process I). The second system consisted of a shredder, followed by a piston press with 12 mm pore size (process II). Both processes produced a dry output, which contained the concentrated impurities, and a wet output, which could be used as substrate for anaerobic digestion. Results showed that, although 99% of the incoming plastics were efficiently removed in process I, the impurities concentration was still too high to meet the legal standards of plastics concentration in the final product, according to the German Federal Compost Quality Association (Bundesgütegemeinschaft Kompost e.V.). The removal efficiency of glass particles was low for both processes: at least 80% of the incoming particles were transferred to the wet output.

Optimising Microbial Fuel Cell Treatment of Wastewater through Electrode Configuration

The cleaning and treatment of wastewater is a necessary, yet energy intensive practice. One of the greatest challenges society faces is therefore how to reduce the energy consumed in this process. A promising pathway to tackle this problem is by using innovative, low or zero energy consuming, technologies such as microbial fuel cells (MFCs), which harness the natural metabolism of bacteria and generate power. These microorganisms breakdown the organic content in wastewater i.e. treat/clean the liquid, and release electrons as part of their anaerobic respiration. Previous studies using MFC technology have been able to reduce the COD of the influent by up to 95% (1). Although MFCs do not generate large amounts of power, by incorporating them into existing treatment systems, the amount of energy needed to further clean wastewater is reduced. In addition, they continuously produce electricity, which can be fed back into the system and used to run low power devices (e.g. pumps for wastewater circulation). The configuration of MFCs greatly affects their performance, with the structure and materials that they are made out of being the governing factors for energy production, catholyte synthesis and wastewater treatment. In response to the need for optimum configuration, this study explores whether the positioning of the anode and cathode (either internally or externally on a cylindrical MFC) has a significant effect on the overall performance of an MFC. Two identical MFCs were tested, with the only variable being the anode and cathode configuration (internal anode with external cathode, and vice versa). The dimensions of the outer electrode were 40mm x 90mm, and 50mm x 70mm for the inner electrode, giving similar surface areas of 36cm2 and 35cm2, respectively. Results have so far shown that MFCs with the anode inside the cylinder and the cathode outside produce power outputs which are three times greater than those with internal cathodes and external anodes, with peak power outputs of 655µW and 219µW respectively. Practically, the benefits of having an internal anode include the advantage of using the MFC directly as part of the hydraulic (pipe) network, with the substrate fed through directly. This kind of design reduces the amount of external plumbing that is needed throughout the structure, and therefore reduces the risk of leakage. In addition, the external cathode can be partially covered or contained, which allows the half-cell to remain hydrated, and for any excess liquid (catholyte) to be easily collected. This is highly desirable due to the disinfectant properties of this liquid (2), which once again can be fed back into a wastewater treatment system and reduce overall energy demand. The acquisition of this knowledge is essential as MFCs need to be designed to suit target environments and applications, for both industrial and societal means. It is anticipated that the findings of this study will provide the MFC community with a decisive answer to how best design a cylindrical cell, which can be used as benchmark for future research.

Dealing More Effectively with Problematic Substance Use and Crime

AbstractFrom the late 1960s to the mid-1990s, the basic drug-crime policy challenge was to manage social harms associated with the heroin and cocaine epidemics. As they ebbed, the crime-drug policy challenges changed. Alcohol receives greater attention as the leading criminogenic substance. Efforts are under way to improve and expand substance use disorder (SUD) treatment for criminally active populations. Model nontreatment interventions seek to monitor and deter use among individuals whose use endangers others. Two key issues are the continuing high rate of alcohol-related crime and violence and opportunities to expand SUD treatment for criminally active populations under the Affordable Care Act (ACA). Alcohol taxes, regulation of alcohol venues, and model programs such as Dakota 24/7 are promising paths to reduced alcohol-related crime. Problem-solving courts can be made more pertinent to the broad range of drug-involved offenders. Existing treatment systems face many challenges in providing mental and...

Carbon Footprint Analyses of Wastewater Treatment Systems in Puducherry

Carbon footprint analysis is a method to quantify the life cycle Greenhouse Gases (GHGs) emissions and identify the measure to reduce climate change impacts. The Intergovernmental Panel on Climate Change (IPCC) has identified that the global warming and climate change which is one of the most important issues in the domain of environment are caused by the excessive emission of Greenhouse Gases (GHG) mainly constituting Carbon dioxide (CO2), Methane (CH4) and Nitrous oxide (N2O). The municipal wastewater treatment plant receives wastewater for treatment and finally discharges the treated effluent. The emissions of GHG during the treatment of wastewater as well as during the treatment process of sludge and also for energy generation are known to be on-site GHG emissions. Off-site GHG emissions are generated due to transportation and disposal of sludge, off-site energy and chemical production. In Puducherry, the municipal wastewater is being treated using oxidation ponds, Upflow Anaerobic Sludge Blanket (UASB) and Sequencing Batch Reactor (SBR). Wastewater treatment using Sequencing Batch Reactor (SBR) technology is one of the state-of-the art wastewater management systems. In this technology equalization, biological treatment and secondary clarification are performed in a single reactor in a time control sequence. The emissions of GHG from the Oxidation ponds of 12.5 MLD, UASB reactor of 2.5 MLD and SBR of 17 MLD were assessed based on the IPCC guidelines and the total emissions of GHG in terms of equivalent of CO2 were compared. The performance of the SBR is more efficient and the emissions of GHG are less than the emissions in the UASB as well as in oxidation ponds. The emission of GHG in SBR is about 60% of the existing treatment systems of oxidation ponds and UASB thus a reduction of 40% GHG emission could be achieved.

Recovery of organic carbon and phosphorus from wastewater by Fe-enhanced primary sedimentation and sludge fermentation

Abstract A new chemically enhanced primary sedimentation (CEPS) and sludge fermentation process are developed for improved nutrient removal, energy saving and resource recovery in municipal wastewater treatment. The FeCl3-based CEPS with a dosage of 20 mg-Fe/L can remove 75.6% of organic pollutants and 99.3% of PO4-P on average from wastewater. Under natural fermentation conditions, the CEPS sludge undergoes effective hydrolysis and acidogenesis to produce volatile fatty acids (VFAs) and release phosphate as valuable resources. By using CEPS, around 27% of the organic carbon in wastewater influent can be recovered via sludge fermentation, mainly in the form of VFAs, and about 23% of phosphorus recovered for making vivianite fertilizer. In comparison, both the organic and phosphorus recovery ratios from wastewater are under 10% with conventional primary sedimentation and sludge fermentation. CEPS combined with side-stream sludge fermentation can be readily applied in new treatment plants or in a retrofit of existing treatment systems.

1,4‐Dioxane Treatment Technologies

The chlorinated solvent stabilizer 1,4‐dioxane (DX) has become an unexpected and recalcitrant groundwater contaminant at many sites across the United States. Chemical characteristics of DX, such as miscibility and low sorption potential, enable it to migrate at least as far as the chlorinated solvent from which it often originates. This mobility and recalcitrance has challenged remediation professionals to redesign existing treatment systems and monitoring networks to accommodate widespread contamination. Furthermore, remediation technologies commonly applied to chlorinated solvent co‐contaminants, such as extraction and air stripping or in situ enhanced reductive dechlorination, are relatively ineffective on DX removal. These difficulties in treatment have required the industry to identify, develop, and demonstrate new and innovative technologies and approaches for both ex situ and in situ treatment of this emerging contaminant. Great strides have been made over the past decade in the development and testing of remediation technologies for removal or destruction of DX in groundwater. This article briefly summarizes the fate and transport characteristics of DX that make it difficult to treat, and presents technologies that have been demonstrated to be applicable to groundwater treatment at the field scale. ©2016 Wiley Periodicals, Inc.

Municipal landfill leachate characteristics and feasibility of retrofitting existing treatment systems with deammonification – A full scale survey

Leachate characteristics, applied technologies and energy demand for leachate treatment were investigated through survey in different states of Germany. Based on statistical analysis of leachate quality data from 2010 to 2015, almost half of the contaminants in raw leachate satisfy direct discharge limits. Decrease in leachate pollution index of current landfills is mainly related to reduction in concentrations of certain heavy metals (Pb, Zn, Cd, Hg) and organics (biological oxygen demand (BOD5), chemical oxygen demand (COD), and adsorbable organic halogen (AOX)). However, contaminants of concern remain COD, ammonium-nitrogen (NH4N) and BOD5 with average concentrations in leachate of about 1850, 640, and 120 mg/L respectively. Concentrations of COD and NH4N vary seasonally, mainly due to temperature changes; concentrations during the first quarter of the year are mostly below the annual average value. Electrical conductivity (EC) of leachate may be used as a time and cost saving alternative to monitor sudden changes in concentration of these two parameters, due to high correlations of around 0.8 with both COD and NH4N values which are possibly due to low heavy metal concentrations in leachate. The decreased concentrations of heavy metals and BOD5 favor the retrofitting of an existing biological reactor (nitrification/denitrification) with the deammonification process and post denitrification, as this lowers average annual operational cost (in terms of energy and external carbon source) and CO2 emission by €25,850 and 15,855 kg CO2,eq respectively.

An Evaluation of Samarra City Drinking Water Treatment Plants

Global population increases specially in developing countries such Iraq requires more effort and investment in water and sanitation facilities to enhance the welfare of people in meeting the MDG objectives. The competition for water resources coupled with the generation of wastewater is creates additional pressure on the available supplies and increasing pollution level. To address such challenges it has become necessary to build new or enhance existing treatment systems. In different part of Iraq including in Samarra City effort is being made to enhance the water quality in regard to its physical, chemical, and biological characteristics as well as the minerals and organic substances which may produce adverse physiological effects. In order to evaluate different aspect of water quality this study focused on evaluating the drinking water quality and also the performance of the two treatment plants in Samarra City located on the left bank of Tigris River to the north of Baghdad City. The investigation covered the period of December, 2004 to May, 2005. The first is the main conventional water treatment plant with a capacity of 2400m3/hr. and the second is a compact unit with a capacity of 200m3/hr. The collected water data cover some of the important physical and chemical parameters of water quality; covering temperature, TDS, turbidity, pH and residual chlorine. While the bacteriological parameters covered total plate count (TPC) and E-coli for stages of treatment plants. The results show that turbidity of raw water is not high (3.84-425) NTU compared with Al-Karkh water project in Baghdad City (6-1400) NTU, because the intakes of WTPs are located in the downstream of Samarra barrage which serves as a pre-sedimentation tank. Low clarifiers turbidity removal efficiencies of (48.323 %) and (32.09 %) were obtained for treatment plant and compact unit respectively, while for filters removal efficiencies were (63.2 %) and (39.05 %) respectively. The monthly average turbidity of supplied water for conventional water treatment plant and compact unit were (4.3 and 18.2) NTU, the percent of violation to Iraqi Specifications were (29.4 % and 64.7%) respectively. Not always, increasing in raw water turbidity result in an increase in turbidity removal efficiency. pH values and TDS concentrations of supplied water are within Iraqi, EPA and WHO Specifications. Low amount and interrupted chlorination in WTP and CU, so, irregular chlorination results in frequent outbreak of waterborne diseases. It can be recommend to improve the water quality monitoring program through the application of; coagulant aids to overcome the high turbidity of raw water during the rainy season, the hexagonal tube settler in the sedimentation tank of the compact unit to get the designed SOR and anthracite with sand as a dual porous media to increase the filtration rate to overcome the shortage in hot seasons. Also periodic systematic maintenance for different units of treatment plants is required.