Municipal Sewage Treatment Research Articles

Demonstration of an Energy-Neutral, Off-Grid Microbial Fuel Cell System for Decentralized Wastewater Treatment

Water and energy are becoming important priorities as increasing demands on the world’s resources force nations to make sustainable choices. Microbial fuel cells (MFCs) have emerged as a promising technology to provide energy efficient wastewater treatment at significant cost savings compared to conventional aerobic treatment processes. These systems are especially beneficial in areas that are difficult to connect to municipal sewage treatment networks. Initial laboratory results from MFC tests using swine waste indicated that improvements to power output could be achieved with a carbon-fabric pleats design when compared to a previous packed bed design. An 88-liter pilot scale demonstration system was developed based on these results that allowed for full system operation in an energy neutral configuration. Initial results from the startup phase, showed an 80% decrease in chemical oxygen demand (COD) with a 7-day treatment time (fed-batch mode). During continuous flow operation, an average of 93% COD removal was observed.

Assessment of application of selected waste for production of biogas

Recently, the idea of biogas production has become a popular topic in Poland. Biogas is a valuable source of renewable energy with a potential application in electricity and heat production. Numerous types of technological solutions of biogas production are closely linked to the availability of substrates in the area, as well as their quantity and their properties. The paper presents the assessment of application in biogas production selected wastes such as communal and household sewage sludge and waste from a paper production in Opole region (Poland). The annual productions of methane, biogas and electricity were estimated. Chosen physico-chemical properties important in fermentation process were taken into consideration in the assessment. The highest value of potential energy was obtained using waste from the paper industry but the most appropriate parameters for this process has sewage sludge from the municipal sewage treatment plant. The use of sewage sludge from domestic and municipal sewage and waste from the paper industry creates the opportunity to reduce the amount of waste materials.

A modified assay for the enumeration of ascaris eggs in fresh raw sewage

Soil-transmitted helminths (STHs) pose a significant public health problem, infecting approximately 2 billion people globally. Despite relatively low prevalence in developed countries, the removal of STHs from wastewater remains crucial to allow the safe use of biosolids or recycled water for agriculture. Wastewater helminth egg count data can contribute to an assessment of the need for, or success of, a parasite management program. Although the World Health Organisation (WHO) has recommended a standard method for counting helminth eggs in raw sewage based on the method of Bailenger (Ayres et al., 1996), the method generally results in low percentage egg recoveries. Given the importance of determining the presence of STHs, it is essential to develop novel techniques that optimise the recovery rate of eggs from raw sewage. In the present study:•The method described by Bowman et al. (2003) was optimized for the concentration and enumeration of helminth eggs in raw sewage from municipal sewage treatment plants.•The method is simple and reproducible and recovers a greater percentage of helminth eggs compared to the WHO method.

Membrane Bioreactor Processes to Meet Todays and Future Municipal Sewage Treatment Requirements?

Membrane Bioreactor Processes to Meet Todays and Future Municipal Sewage Treatment Requirements?

Anaerobic Biodegradability of Perfluorooctanoic Acid (PFOA)

Perfluorooctanoic acid (PFOA), one of the most typical representatives of perfluoroalkyl surfactants (PASs), has relatively high detection rate and level of pollution, and the accumulation of PFOA in the environment has been a serious threat to human health and security of the whole ecological environment. Therefore, studies on anaerobic biodegradability of PFOA are very important for elucidation of its environmental fate. This study used anaerobic sludge from municipal sewage treatment plant (WWTP) and 5.0 mg·L-1 vitamin B12 (VB12) as catalysts for the degradation of PFOA in the anaerobic environment. The anaerobic biodegradability of PFOA was examined by liquid chromatography tandem mass spectrometry (LC-MS/MS) and ion chromatography while some indictors, such as molar recoveries of PFOA as well as concentrations of fluoride, acetate, 2H-PFOA (F(CF2)6CHFCOOH), and shorter chain (<C8) perfluorocarboxylates (PFCAs) etc., were selected according to the reductive degradation results reported by predecessors. The results indicated that the molar recoveries of PFOA significantly decreased from 101%±5% at the initial incubation (3 d) to 85.6%±3.9% at the end of incubation (250 d), while fluoride concentrations significantly increased from 0.59 mg·L-1±0.02 mg·L-1 at the initial incubation (3 d) to 0.63 mg·L-1±0.02 mg·L-1 at the end of incubation (250 d) in biodegradation samples. Meanwhile, certain amounts of acetate, 2H-PFOA, and short-chain PFCAs, the products of reductive degradation of PFOA reported by precursors, were detected in biodegradation samples. However, there was no significant difference between these indicators in biodegradation samples and their corresponding controls. Therefore, no evidences were found to certify the anaerobic biodegradability of PFOA under the conditions described in present study, though the microorganisms were able to obtain enough energy for growth from reductive defluorination of PFOA in the thermodynamic aspects.

Salting the Earth: The Environmental Impact of Oil and Gas Wastewater Spills.

Salting the Earth: The Environmental Impact of Oil and Gas Wastewater Spills.

Determination and characterization of pharmaceuticals in sludge from municipal and livestock wastewater treatment plants

This study investigated 24 pharmaceuticals compounds belonging to the classes of analgesics, stimulants, anti-seizures, non-steroidal anti-inflammatory drugs (NSAIDs), and antibiotics in the sludge of 12 municipal sewage treatment plants (S-sludge) and 4 livestock wastewater treatment plants (L-sludge) located across Korea. Over 70% of the target compounds were detected in at least one sample of S-sludge and L-sludge. The total concentration of the target pharmaceutical compounds detected in S-sludge was 2.622–422.8 mg kg−1and the most dominant compound was acetylsalicylic acid (ASA: 0.374–367.0 mg kg−1) whereas in L-sludge, the total concentration was 43.87–156.8 mg kg−1and the most abundant compound was oxytetracycline (OTC: 34.54–86.39 mg kg−1). Cluster analysis revealed two distinct groups: group A, which were S-sludge samples including ASA, carbamazepine (CBM), and others, and group B were L-sludge samples, dominated by antibiotics (CTC, OTC, LIN). The total daily load amount of the target pharmaceuticals in S-sludge was 0.010–268.9 kg day−1 while the L-sludge was 0.021–0.529 kg day−1. The estimated amounts of the target pharmaceutical discharged from S-sludge and L-sludge into the Korean environment were 150.2 ± 47.94 ton yr−1 and 15.05 ± 5.671 ton yr−1 respectively, but the discharged amount of antibiotics from S-sludge (6.945 ton yr−1) was lower than that from L-sludge (9.234 ton yr−1).

Two decades of system-based hygienic–microbiological research in Swist river catchment (Germany)

A multidisciplinary research project series has sought to identify and better understand multiple hygienic–microbiological and chemical contaminations from both point sources and diffuse pollution to contribute to the improvement in surface water quality. In the catchment area of the river Swist (Germany), municipal sewage treatment plants were investigated, followed by event-based investigation of combined sewer overflows, rainwater retention basins and diffuse pollution by surface and subsurface run-off as well as drain pipes. Recently, retention soil filters installed between stormwater storage basins and receiving surface waters in order to provide further treatment of combined sewer overflows were investigated. Geographical information system analysis helped to examine the data in their temporal and spatial dimensions. A model for calculating microbial and chemical loads within a catchment area was developed (“Swistbox”) which provides an efficient tool for risk assessment. Nearly two decades of investigation has demonstrated that several elements of the landscape’s water balance account for surface water pollution from both diffuse and point sources. Depending on land cover characteristics, wastewater technology and the proportion of wastewater as compared to total river water flow, a source can vary in its importance for the catchment area. The findings can be applied for sustainable and health-sensitive catchment management in relation to recreational or agricultural water use as well as ecological aspects.

New nitrogen removal pathways in a full-scale hybrid constructed wetland proposed from high-throughput sequencing and isotopic tracing results

Constructed Wetlands (CWs), which usually feature limited supply of electron acceptors, possess complex microbial nitrogen removal pathways. Based on Illumina high-throughput sequencer, 15N isotopic tracer, and three years of physicochemical analysis, in this study, we report on a complex microbial consortium responsible for the nitrogen removal in a full-scale hybrid CW, consisted of vertical-baffled flow wetland (VBFW, first stage) and horizontal subsurface flow wetland (HSFW, second stage), receiving municipal sewage. Two organotrophic anaerobic ammonium oxidation (anammox) bacteria, Candidatus ‘Anammoxoglobus propionicus’ and ‘Brocadia fulgida’, chemolitho-autotrophic denitrifiers mainly Thiobacillus denitrificans, heterotrophic denitrifiers, ammonia oxidizers, and nitrite oxidizers were found in the HSFW, which achieved a mean total nitrogen removal load of 3.7gNm−2 d−1 in the summer season. A phylogenetic analysis and isotopic incubation experiment revealed that simultaneous autotrophic denitrification, heterotrophic denitrification and anammox processes contributed to the nitrogen loss from the system, which composed of a complex nitrogen removal scheme in a full-scale CW for low-strength municipal sewage treatment. Sulphur-oxidizing Thiobacillus denitrificans, the most abundant bacterial species in HSFW sediments, can convert nitrate to nitrite and support anammox bacteria with the necessary substrate to complete nitrogen removal. The present study confirmed the presence of anammox process in a full-scale CW and indicated that the nitrogen removal pathways in CWs are much more complex than we previous thought.

Vitellogenin induction and reduced fecundity in zebrafish exposed to effluents from the City of Bulawayo, Zimbabwe

Industrial and municipal effluents regularly pollute water bodies and cause various toxic effects to aquatic life. Because of the diverse nature of industrial processes and domestic products, urban effluents are often tainted with various anthropogenic endocrine disrupting chemicals that may interfere with the reproductive physiology of aquatic fauna. In this study, we tested effluents from the City of Bulawayo for the presence of estrogenic endocrine disrupting chemicals and their effects on fish gonads and fecundity. Effluents were collected from two sewage treatment plants (STPs), which receive largest volume of industrial effluents from the City, and from a textile factory. Male and female zebrafish (Danio rerio) were exposed to effluents and analyzed for vitellogenin induction, gonad alterations, and fertility. Male zebrafish exposed to effluent from Thorngrove STP had significantly higher (p ≤ 0.05) vitellogenin compared to control. Textile effluent caused adverse gonad alterations such as oocyte atresia (females) and increased proportion of spermatogonia (males) which could lead to reduced fertility. Textile effluent (5% v/v) and Thorngrove effluent also caused a decline in fertilization success of breeding groups of zebrafish. The results of this study show the potential effects of effluent pollution and the occurrence of EDCs in developing countries. This underscores the need to effectively prevent pollution of environmental water bodies from industrial and municipal sewage treatment plant effluents. We recommend a follow-up study to monitor the effects of the effluents on feral fish in effluent polluted downstream dams of Bulawayo.

Effects of ultrasonic disintegration of excess sewage sludge.

Breaking down sludge floc (sonodyspergation effect) and destruction of the cell membranes of microorganisms forming floc is a direct effect of ultrasonic disintegration of sludge excess. This results in release of organic material by liquid sludge (the sonolysis effect). Desired technological effects of the disintegration are: to shorten the hydrolytic phase of fermentation, to increase the production of biogas (source of renewable energy) and an increased mineralization (stability) of fermented sludge. The presented study demonstrates research covering thickened excess sludge of various physicochemical properties, collected from nine municipal sewage treatment plants. The sludge was subjected to ultrasonic disintegration using three differently constructed disintegrators and different proportions of sonification area. Direct effects of disintegration were monitored and recorded using selected indicators describing changes in the properties of sludge and increase of substance dispersed and dissolved in the supernatant liquid to be filtered. Studies have demonstrated that those (direct) effects of ultrasonic disintegration depend on the physicochemical properties of the sludge (foremost the concentration of dry solids) that determine their variable susceptibility to the disintegration methods. The direct effects also depend on optimal process conditions (which consist of the construction of the ultrasonic disintegrator), the geometric proportions of the sonication area and the operating parameters of disintegration (which could be appropriately matched to the characteristics of sludge). The most preferable results were obtained for ultrasonic disintegration of sludge with a dry matter concentration C 0<4.2%. The highest effect of sonolysis-an almost 30-fold increase in the COD dissolved in the supernatant-was obtained for the sludge of lowest dry matter (C 0=2.0%), which was sonicated in a reactor with a short transducer of the largest radiating surface area, as well as the lowest ratio between this area and area of reactor. The best effects of disagglomeration of flocks have corresponded with the high value of power density U UD=880-900WL(-1).

Demonstration of an Energy Neutral, Off-Grid Microbial Fuel Cell System for Decentralized Wastewater Treatment

Water and energy are main priorities for much of the world as increasing demands on the world’s resources forces nations to make sustainable choices. Microbial fuel cells emerged as a promising technology to provide energy efficient wastewater treatment at significant cost savings compared to conventional treatment processes. They have an even greater benefit in those areas that are difficult to connect to municipal sewage treatment networks. We discuss here a pilot scale demonstration at a rural Naval training camp in Warner Springs, CA. The system is a 100 gallon system outfitted with a solar energy system that allows full system operation in an energy neutral configuration. The system configuration here was previously tested in the laboratory using wastewater in semi-batch operation at both the 40 gallon scale and 100 gallon scale. Laboratory studies indicated that a 7-day batch treatment time would result in high removal of biological oxygen demand. Effluent quality was also good with more than 99% removal of suspended solids, turbidity, and nitrogen. Before deployment to the field, the system was rebuilt using lessons learned from the laboratory studies and other large scale demonstrations. Considerations for size, portability, ease of use, and operations were considered here and will be discussed. The overall goal for the field-deployed system was to demonstrate continuous treatment at rate of 20 gallon per day. Initial results from the startup phase operating in semi-batch mode show promising results, decreasing the COD content more than 80% over a 7-day treatment time. Results from the ongoing demonstration will also be discussed here. The system here represents a significant move towards providing decentralized wastewater treatment. We examine the feasibility of applying this technology in an off-grid application to meet a real-world requirement. We will also examine lessons learned from the demonstration and possible improvements to incorporate into the next iterations of these types of systems.

Ecotoxicity Assessment of Stabilized Sewage Sludge from Municipal Sewage Treatment Plant

Aim of this study was to evaluate the ecotoxicity of municipal sewage sludge conditioned with polyelectrolytes, taken from selected sewage treatment plant. Using the bioindication analysis overall toxicity was assessed, which allows to know the total toxicity of all the harmful substances contained in sewage sludge, in many cases acting synergistically. To prepare a sample of sludge for the basic test, all analyses were performed with a ratio of liquid to solid of 10:1 (water extract). Daphnia pulex biological screening test was used. A dilution series of an water extract of sludge were prepared to include within its scope the lowest concentration that causes 100% effect and the highest producing less than 10% of the effect within a specified range of the assay. The results of the test were read after 24 and 48 hours. Based on the research and analysis of test results it proved that the sewage sludge conditioned with polyelectrolytes exhibit the characteristics of eco-toxic.

Estimation of phosphorus bioavailability from composted organic wastes

Sewage sludge derived from municipal sewage treatment plants is an important source of macronutrients, micronutrients and organic matter. For this reason composting of sewage sludge, along with combustion and co-combustion, is a new management priority in Poland. In this study six composts of different origin and composition were evaluated in terms of their abundance in phosphorus, because it is an essential nutrient for all living organisms. Analyses were conducted on the samples at the initial and at the maturation phase of composting. The bioavailability of phosphorus was estimated on the basis of amounts of the nutrient in isolated fractions using the sequential extraction method. First of all quantitative changes of the total nutrient content and its amounts in separated fractions were dependent on the mixture composition. Irrespective of compost type, 34.5–75.0% of the total amounts of phosphorus were found in hardly available combinations (Fr. III), while available phosphorus forms (Fr. I) accounted for only 6.6–21.6%. As a result of composting together different organic wastes an increase was observed both in the total content and the amounts of this nutrient in separated fractions. This phenomenon was observed particularly in composts with smaller levels of sewage sludge (30–40%), characterised by rapid organic matter decomposition, which was indicated by higher bioavailable amounts of phosphorus. Under such conditions the content of P ranged between 3.68 and 7.4 g kg−1. In comparison to the labile pool of P obtained for matured composts C5 and C6 (65 and 75% of sewage sludge in their composition) amounting to 2.45–3.0 g kg−1 the above values were considerable. Bioavailable phosphorus contents potentially introduced to soil with composts doses calculated at 170 kg total N/ha/yr ranged from 69.8 to 80.2 kg for compost with the lowest share of sewage sludge and from 11.2 to 20.7 kg for compost with the highest share of sewage sludge.

Performance evaluation of panelled anaerobic baffle-cum-filter reactor in treating municipal wastewater

A panelled anaerobic baffle-cum-filter reactor (PABFR) was developed to treat municipal wastewater in tropical climatic condition. The performance of the reactor was evaluated with respect to start-up mechanism, pollutant removal behaviour by varying hydraulic retention time (HRT) at different organic loading rates (OLR), resistance to shock loading, restart behaviour after a shutdown period and its potential to remove pathogen indicator. Acclimatization curve was plotted. It indicated a successful start-up period of 61days with a COD removal efficiency of more than 90%. The alkalinity to volatile acid ratio was less than 0.5, which confirms reactor stability. Performance evaluation of the reactor was carried out for more than 682days at 7 different HRTs ranging from 2h to 40h. The HRT of 8h was found to be appropriate for PABFR configuration with removal efficiencies of 95%, 91% and 90% for suspended solids (SS), biochemical oxygen demand (BOD), and chemical oxygen demand (COD), respectively. The recovery of the reactor after hydraulic shock (both transient and step) was two times better compared to conventional ABR because of the filter media present in the rear part of the PABFR. Reactivation after a short shutdown period was quick and yielded efficient treatment. The removal efficiency of the pathogen indicator was above 97.2% at a HRT of 8h, but it is necessary to adopt appropriate post-treatment measures to guarantee reuse. Thus, with the above-mentioned properties, the PABFR is a suitable technology for decentralized municipal sewage treatment in suburban and rural areas of India.

Comparative genomics analyses on EPS biosynthesis genes required for floc formation of Zoogloea resiniphila and other activated sludge bacteria

Activated sludge (AS) process has been widely utilized for municipal sewage and industrial wastewater treatment. Zoolgoea and its related floc-forming bacteria are required for formation of AS flocs which is the key to gravitational effluent-and-sludge separation and AS recycling. However, little is known about the genetics, biochemistry and physiology of Zoogloea and its related bacteria. This report deals with the comparative genomic analyses on two Zoogloea resiniphila draft genomes and the closely related proteobacterial species commonly found in AS. In particular, the metabolic processes involved in removal of organic matters, nitrogen and phosphorus were analyzed. Furthermore, it is revealed that a large gene cluster, encoding eight glycosyltransferases and other proteins involved in biosynthesis and export of extracellular polysaccharides (EPS), was required for floc formation. One of the two asparagine synthase paralogues, associated with this EPS biosynthesis gene cluster, was required for floc formation in Zoogloea. Similar EPS biosynthesis gene cluster(s) were identified in the genome of other AS proteobacteria including polyphosphate-accumulating Candidatus Accumulibacter phosphatis (CAP) and nitrifying Nitrosopira and Nitrosomonas bacteria, but the gene composition varies interspecifically and intraspecifically. Our results indicate that floc formation of desired AS bacteria, including CAP strains, facilitate their recruitment into AS and gradual enrichment via repeated AS settling and recycling processes.

An Analysis of the Effects of Vancomycin and/or Vancomycin-Resistant Citrobacter freundii Exposure on the Microbial Community Structure in Soil.

The occurrence of antibiotics and antibiotic resistance genes in the environment has become a subject of growing concern. The extensive use of vancomycin and other pharmaceuticals may alter the biodiversity of soil microbial communities and select antibiotic-resistant bacteria. Therefore, the purpose of the study was to evaluate the impact of vancomycin and/or vancomycin-resistant Citrobacter freundii on soil microbial communities using the denaturing gradient gel electrophoresis (DGGE) and the phospholipid fatty acid (PLFA) approaches. The experiment had a completely randomized block design with the following treatments: control soil (C), soil with vancomycin (1 mg/kg soil—VA1), soil with vancomycin (10 mg/kg soil—VA10), soil with C. freundii (Cit), soil with vancomycin (1 mg/kg soil) and C. freundii (VA1+Cit), and soil with vancomycin (10 mg/kg soil) and C. freundii (VA10+Cit). A bacterial strain resistant to vancomycin was isolated from raw sewage collected from the municipal sewage treatment plant. The obtained results indicated that the antibiotic and/or the bacterial strain exerted a selective pressure that resulted in qualitative and quantitative changes in the population of soil microorganisms. However, a multivariate analysis showed that the genetic and structural diversity of the soil microbial community was primarily affected by the incubation time and to a lesser extent by the antibiotic and introduced bacteria. DGGE analysis clearly showed that certain species within the bacterial community were sensitive to vancomycin as was evidenced by a decrease in the values of S (richness) and H (Shannon-Wiener) indices. Moreover, a PLFA method-based analysis revealed alterations in the structure of the soil microbial community as indicated by changes in the biomass of the PLFA biomarkers specific for Gram-positive and Gram-negative bacteria as well as fungi. The changes observed in the community of soil microorganisms may decrease the rate of microbial-mediated processes, which can lead to a disturbance in the ecological balance of the soil ecosystem.

Adapting SimpleTreat for simulating behaviour of chemical substances during industrial sewage treatment

The multimedia model SimpleTreat, evaluates the distribution and elimination of chemicals by municipal sewage treatment plants (STP). It is applied in the framework of REACH (Registration, Evaluation, Authorization and Restriction of Chemicals). This article describes an adaptation of this model for application to industrial sewage treatment plants (I-STP). The intended use of this re-parametrized model is focused on risk assessment during manufacture and subsequent uses of chemicals, also in the framework of REACH. The results of an inquiry on the operational characteristics of industrial sewage treatment installations were used to re-parameterize the model. It appeared that one property of industrial sewage, i.e. Biological Oxygen Demand (BOD) in combination with one parameter of the activated sludge process, the hydraulic retention time (HRT) is satisfactory to define treatment of industrial wastewater by means of the activated sludge process. The adapted model was compared to the original municipal version, SimpleTreat 4.0, by means of a sensitivity analysis. The consistency of the model output was assessed by computing the emission to water from an I-STP of a set of fictitious chemicals. This set of chemicals exhibit a range of physico-chemical and biodegradability properties occurring in industrial wastewater. Predicted removal rates of a chemical from raw sewage are higher in industrial than in municipal STPs. The latter have typically shorter hydraulic retention times with diminished opportunity for elimination of the chemical due to volatilization and biodegradation.

The INCA-Pathogens model: An application to the Loimijoki River basin in Finland

Good hygienic quality of surface waters is essential for drinking water production, irrigation of crops and recreation. Predictions of how and when microbes are transported by rivers are needed to protect downstream water users. In this study we tested the new process-based INCA-Pathogens model in the agricultural Loimijoki River basin (3138km2) in Finland, and we quantified ecosystem services of water purification and water provisioning for drinking and recreation purposes under different scenarios. INCA is a catchment scale process based model to calculate pollutant transfer from terrestrial environment and point sources to the catchment outlet. A clear gradient was observed in the numbers of faecal coliforms along the River Loimijoki. The highest bacterial counts were detected in the middle part of the main stream immediately after small industries and municipal sewage treatment plants. In terms of model performance, the INCA-Pathogen model was able to produce faecal coliform counts and seasonality both in the low pollution level sampling points and in the high pollution level sampling points. The model was sensitive to the parameters defining light decay in river water and in soil compartment, as well as to the amount of faecal coliforms in the manure spread on the fields. The modeling results showed that the number of faecal coliforms repeatedly exceeded 1000 bacteria 100ml−1. Moreover, results lead to the following conclusions: 1) Climate change does not cause a major threat to hygienic water quality as higher precipitation increases runoff and causes diluting effect in the river, 2) Intensification of agriculture is not a threat as long as animal density remains relatively low and environmental legislation is followed, 3) More intensive agriculture without environmental legislation causes a threat especially in tributaries with high field percentage and animal density, and 4) Hygienic water quality in the River Loimijoki can best be improved by improving sewage treatment. We conclude that this catchment scale model is a useful tool for addressing catchment management and water treatment planning issues.

Removal and degradation of β-lactam antibiotics in water using didodecyldimethylammonium bromide-modified montmorillonite organoclay

β-Lactam antibiotics including penicillin G, nafcillin, cefazolin, cefotaxime, and oxacilline in water were rapidly removed and degraded by using didodecyldimethylammonium bromide (DDAB)-montmorillonite (MT) organoclay. Removal of antibiotics increased with increasing the amount of organoclay added and the amount of DDAB sorbed on MT. Extents of organoclay sorption of antibiotics were represented by the binding constants to DDAB molecules and correlated to the aqueous-octanol distribution coefficients. The degradation rate of β-lactam antibiotics was found to significantly increase by the organoclay sorption. Even under the mild conditions (25°C and pH 7), penicillin G (m/z=335) nearly completely (>98%) degraded into penicilloic acid (m/z=353) missing β-lactam ring within 2h. The first-order reaction rate of the primary degradation increased with increasing in temperature. The activation energy estimated from the Arrhenius plot was 49kJmol−1 and lower than the value (83.5kJmol−1) in water, strongly suggesting catalytic activity of DDAB-MT organoclay. The applicability to wastewater treatment was demonstrated by using secondary effluents of municipal sewage treatment plants and synthesized hospital wastewaters.