Sanitary Wastewater Research Articles

The impact of socio-economic development and climate change on E. coli loads and concentrations in Kabul River, Pakistan

Microbial pollution is a major problem worldwide. High concentrations of Escherichia coli have been found in Kabul River in Pakistan. E. coli concentrations vary under different socio-economic conditions, such as population and livestock densities, urbanisation, sanitation and treatment of wastewater and manure, and climate-change aspects, such as floods and droughts. In this paper, we assess potential future E. coli loads and concentrations in the Kabul River using the Soil and Water Assessment Tool with scenarios that are based on the most recent Shared Socio-economic Pathways and Representative Concentration Pathways (SSPs and RCPs) developed for the Intergovernmental Panel on Climate Change (IPCC). Scenario_1 considers moderate population and livestock density growth, planned urbanisation and strongly improved wastewater and manure treatment (based on SSP1, “Sustainability”), and moderate climate change (RCP4.5, moderate greenhouse gas (GHG) emissions). Scenario_2 considers strong population and livestock density growth, moderate urbanisation, slightly improved wastewater treatment, no manure treatment (based on SSP3, “Regional rivalry”) and strong climate change (RCP8.5, high GHG emissions). Simulated E. coli responses to Scenario_2 suggest a mid-century increase in loads by 111% and a late century increase of 201% compared to baseline loads. Similarly, simulated E. coli loads are reduced by 60% for the mid-century and 78% for the late century compared to the baseline loads. When additional treatment is simulated in Scenario_1, the loads are reduced even further by 94%, 92% and 99.3% compared to the baseline concentrations when additional tertiary treatment, manure treatment or both have been applied respectively. This study is one of the first to apply combined socio-economic development and climate change scenario analysis with an E. coli concentration model to better understand how these concentrations may change in the future. The scenario analysis shows that reducing E. coli concentrations in Pakistan's rivers is possible, but requires strongly improved waste water treatment and manure management measures.

FECAL CONTAMINATION AND THE PROPORTION OF HUMAN-ASSOCIATED E. coli ALONG NHUE RIVER, VIET NAM

According to rapid urbanization in Asian countries, the amount of domestic wastewater discharge has been increasing, resulted in water pollution and potential health risk on human. To secure biological safety of rivers, it is critical to understand the sources of contamination. The present study applied the human-associated E.coli genetic marker (H8) to characterize the source of microbial contamination. E. coli concentration and other pollutants indices were investigated at 10 sites along the river: S1 (upstream) – S10 (downstream). For 220 E. coli isolates collected from river water samples, Real-Time PCR was performed with H8. The results showed that organic pollutants peaked at the middle stream, although they were originally low at upstream (S1). The positive proportion of H8 with E. coli peaked at 40.9 % at middle stream (S6), which was significantly higher than S1 (4.5 %) (p = 0.012). This high proportion implied the relative dominance of human-associated E. coli, which were in line with a large inflow of sanitary wastewater in middle stream, indicated by land use along the river. Thus, we successfully demonstrated the usefulness of H8 to track the source of microbial contamination in the river.

Automated detection of sewer pipe defects in closed-circuit television images using deep learning techniques

Abstract Sanitary sewer systems are designed to collect and transport sanitary wastewater and stormwater. Pipe inspection is important in identifying both the type and location of pipe defects to maintain the normal sewer operations. Closed-circuit television (CCTV) has been commonly utilized for sewer pipe inspection. Currently, interpretation of the CCTV images is mostly conducted manually to identify the defect type and location, which is time-consuming, labor-intensive and inaccurate. Conventional computer vision techniques are explored for automated interpretation of CCTV images, but such process requires large amount of image pre-processing and the design of complex feature extractor for certain cases. In this study, an automated approach is developed for detecting sewer pipe defects based on a deep learning technique namely faster region-based convolutional neural network (faster R-CNN). The detection model is trained using 3000 images collected from CCTV inspection videos of sewer pipes. After training, the model is evaluated in terms of detection accuracy and computation cost using mean average precision (mAP), missing rate, detection speed and training time. The proposed approach is demonstrated to be applicable for detecting sewer pipe defects accurately with high accuracy and fast speed. In addition, a new model is constructed and several hyper-parameters are adjusted to study the influential factors of the proposed approach. The experiment results demonstrate that dataset size, initialization network type and training mode, and network hyper-parameters have influence on model performance. Specifically, the increase of dataset size and convolutional layers can improve the model accuracy. The adjustment of hyper-parameters such as filter dimensions or stride values contributes to higher detection accuracy, achieving an mAP of 83%. The study lays the foundation for applying deep learning techniques in sewer pipe defect detection as well as addressing similar issues for construction and facility management.

Treatment of a pesticide industry wastewater mixture in a moving bed biofilm reactor followed by conventional and membrane processes for water reuse

The treatment of an industrial wastewater (Efmix) composed of sanitary wastewater (91.5%), pretreated wastewater from pesticide production (3.8%) and hazardous waste landfill leachate (4.7%) was investigated in a moving bed biofilm reactor (MBBR) at a hydraulic retention time of 6 h. Treated effluent was then mixed with surface water (EfMBBR + SW) in a 1:9 volumetric ratio and physicochemical processes (coagulation/flocculation, sedimentation, rapid sand filtration and cartridge filter) were applied in lab-scale to reproduce the industrial water treatment plant and verify the efficiency of the combined process for wastewater reclamation. During the 90 days of operation, the moving bed biofilm reactor was efficient and stable regarding the removal of organic matter (64–89% in terms of chemical oxygen demand) and ammonium nitrogen (89–98%). Even with a fluctuating inlet chemical oxygen demand (230–721 mg/L), values below 100 mg/L were always achieved after biological treatment. Ammonium nitrogen (1.3 ± 0.6 mg NH4+-N/L) and nitrate (20 ± 4 mg NO3⁻-N/L) concentrations in treated wastewater showed that nitrification took place without inhibition throughout the bioreactor operation. Advanced treatment results indicated that a microfiltration or ultrafiltration unit must be coupled to the existing conventional reverse osmosis pretreatment in the water treatment plant in order to improve water quality concerning SDI15, turbidity and color, and thus allow for total reclamation of the industrial complex wastewater. An integrated conventional-microfiltration/ultrafiltration system could achieve high turbidity (99.9%) and apparent color (96.7%) removal to produce high quality water for reverse osmosis, minimizing membrane fouling problems and, consequently, the operational costs.

DIALECTICS OF THE TOTALITY OF THEORETICAL, METHODOLOGICAL AND NORMATIVE PROVISIONS APPLIED FOR THE DESIGN OF THE SETTLEMENTS SEWAGE SYSTEM

On the base of the system analysis of technical literature and regulatory documentation on the sewerage of sett lements and industrial enterprises it is established that in the history of the development of sanitary equipment for the period from the middle of the 19th century onwards up to the present time it is possible to roughly distinguish fi ve stages diff ering from each other in that for a certain period of time in developed countries a certain system of theoretical and normative provisions on the collection, removal and disposal of sewage water dominated. In the fi rst quarter of the XX century the generally accepted paradigm is the method of sewerage of sett lements by a centralized scheme with the installation of communal sewage treatment plants by a biological method. At the beginning of the XXI century there is a paradigm shift in the collection, management and purifi cation of domestic wastewater due to the resumption of search for resource-saving technologies that reduce the emission of pollutants into the environment through the introduction of technological solutions for the separation of domestic (sanitary) wastewater into separate fl ows for the purpose production from waste water components of secondary products. In the short term, after the development and approval of normative documents regulating the basic sanitary rules and technological norms for the introduction of advanced modifi ed technologies for the separation of human excrement and household wastewater with the purpose of separate treatment with the disposal of sewage components, a gradual transition from a centralized to a decentralized separate sewerage system will be carried out domestic and sanitary sewage.

Combined use of biogas from sanitary landfill and wastewater treatment plants for distributed energy generation in Brazil

Biogas is a fuel which has a high potential energy and it is produced from the anaerobic degradation of organic material. It can be used for many applications such as heat and electrical generation and fueling vehicles. Given that anaerobic reactors and landfills are the main forms for treating domestic solid waste in Brazil, this current article presents a five scenario analysis on the energy potential and economic viability of the combined use of biogas produced in these structures for generating electricity in the city of Itajubá, Brazil. From the energy point of view, the best case scenario is the combined use of biogas from sanitary landfill and sewage treatment station. This scenario resulted in an installed power of 685 kW, with an annual energy production capable of supplying approximately 10% of the city’s energy. Concerning the economic aspect, the best option is the use of biogas from sanitary landfill in an isolated manner, due to the shorter distance of the transport of the gas, in comparison with other scenarios. The results demonstrate the potential and possibility of economic viability for the use of biogas in urban structures for these microregions in Brazil, indicating that the development of biogas use in small cities can be accomplished within the resolutions of distributed microgeneration. Such potential tends to increase as basic sanitation grows throughout the country.

Microbiological Quality Assessment of Drinking Water in Teros Village, East Lombok District, West Nusa Tenggara Province, Indonesia

Although the source of drinking water is abundantly available in East Lombok District, its quality raises a public health concern. The East Lombok District, especially Teros Village at Labuhan Haji District is mainly characterized by several springs and very shallow water levels. Teros village communities regularly use water from springs or from dug wells to meet their daily needs. The springs are scattered and located in the middle of densely populated settlements. This results in the high possibility of groundwater contamination or pollution by human activities. This research primarily aims at studying the microbiological water quality of drinking water at Teros Village, and to review household water treatments methods employed by the local population and also the sanitation condition. Eight water samples were taken from six dug wells and two springs and were analyzed with measured microbiological parameters namely coliform and fecal coli. It is revealed that there is a significant degree of microbiological pollution of drinking water in this area owing to domestic wastewater and poor sanitation condition. By using purposive sampling technique, 100 respondents (Head of Family) were selected to collect qualitative data regarding local household water treatment methods. This amount based on the reason that one house with one water source is usually inhabited and used by some families so that the number of respondents is considered enough to represent the existing conditions. Field observation was conducted to find out the sanitation condition. Local residents were familiar with several household water treatments methods, although they only knew about limited physical characteristics of water improvement.

Pathotyping of Escherichia coli isolated from community toilet wastewater and stored drinking water in a slum in Bangladesh.

Sanitary wastewater from an urban slum was heavily contaminated with pathogenic Escherichia coli. It is worth noting a great health risk of accidental exposure to pathogenically contaminated wastewater improperly discharged in and around urban slums. The distinct difference in pathotypes between wastewater and drinking water and the significantly smaller positive proportion of the human-specific E.coli genetic biomarker (H8) in drinking water indicate that drinking water contamination could be derived from not only human but also other sources. This highlights that pathotyping in association with the H8 marker provides an indication of pathogen contamination sources of environmental transmission media.

Human Aspects of Water Management at Impoverished Settlements. The Case of Doornkop, Soweto

Since 1996, the South African government has undertaken a considerable project to fulfil the proclaimed right of citizens to access sufficient water and sanitation (Government of South Africa, 1996) through traditional water management and water governance. However, democracy has not yet provided significant improvements to informal dwellers. Doornkop (Soweto) is a clear example of a community fighting for its rights to access clean water and adequate wastewater sanitation systems. Beyond traditional water management and social and environmental water governance, an ethical view of managing water policies through principles of “human dignity” and “human equality” has arisen in order to provide basic water services. Equal opportunities to manage water are provided, analysing the impact of the principles of the United Nations Educational, Scientific and Cultural Organisation (UNESCO) upon South African informal communities through the implementation of human water governance. The objectives of the study ascertain if those two principles are relevant to improve the community’s living conditions as well as to positively affect the “Principles of water governance” and the “Water principles”. With this aim, a case study was set up at Doornkop (Soweto), in which 416 informal dwellers among a relocated group, a tenure group and a squatter group were tested through the Smart PLS method. Results showed that water services can be highly improved through human water management, a model that can be applied to other underdeveloped areas in the world.

An environmental-friendly study on sanitary wastewater treatment for small community

An environmental-friendly study on sanitary wastewater treatment for small community

The water treatment and recycling in 105-day bioregenerative life support experiment in the Lunar Palace 1

In the bioregenerative life support system (BLSS), water recycling is one of the essential issues. The Lunar Palace 1, a ground-based bioregenerative life support system experimental facility, has been developed by our team and a 105-day closed bioregenerative life support experiment with multi-crew involved has been accomplished within this large-scale facility. During the 105-day experiment, activated carbon-absorption/ultra-filtration, membrane-biological activated carbon reactor and reduced pressure distillation technology have been used to purify the condensate water, sanitary & kitchen wastewater and urine, respectively. The results demonstrated that the combination of those technologies can achieve 100% regeneration of the water inside the Lunar Palace 1. The purified condensate water (the clean water) could meet the standards for drinking water quality in China (GB5749-2006). The treatment capacity of the membrane-biological activated carbon reactor for sanitary & kitchen wastewater could reach 150 kg/d. During the 105-d experiment, the average volume loading of the bioreactor was 0.441 kgCOD/(m3d), and the average COD removal efficiency was about 85.3%. The quality of the purified sanitary & kitchen wastewater (the greywater) could meet the standards for irrigation water quality (GB 5084–2005). In addition, during the 105-day experiment, the total excreted urine volume of three crew members was 346 L and the contained water was totally treated and recovered. The removal efficiency of ion from urine was about 88.12%. Moreover, partial nitrogen within the urine was recovered as well and the average recovery ratio was about 20.5%. The study laid a foundation for the water recycling technologies which could be used in BLSS for lunar or Mars bases.

Banana fertigation with treated sanitary wastewater: postharvest and microbiological quality

Sewage may serve as a source of water and nutrients for plants. In this study, the effects of fertigation with treated sanitary wastewater from Janaúba Sewage Treatment Plant were evaluated on the postharvest and microbiological quality of ‘Prata-Anã’ banana. A randomized block experimental design was used. Four concentrations of wastewater were tested (70, 130, 170, and 200% of 150 kg ha-1 sodium). A wastewater-free control treatment was used for comparison. Two crop cycles were assessed for postharvest and microbiological quality. The parameters measured included total soluble solids, titratable acidity, total soluble solids/titratable acidity ratio, pH, total coliforms, and fecal coliforms on both the peel and the pulp. In the first crop cycle, both soluble solids and fruit pulp pH decreased as wastewater level increased up to a maximum of 141.5%. These correlations were not observed in the second cycle. Wastewater management did not affect the titratable acidity of the soluble solids. The agricultural application of treated sanitary wastewater provided banana fruits with a microbiological profile similar to that obtained with the control (pure water) and with mineral fertilizers. A microbial balance is necessary to maintain the nutritional status of the banana crop.

Application of response surface method to compare the performance of Wetland and extended aeration system for the removal of organic matter from sanitary wastewater

Application of response surface method to compare the performance of Wetland and extended aeration system for the removal of organic matter from sanitary wastewater

CHANGES IN SOIL CHEMICAL PROPERTIES PROMOTED BY FERTIGATION WITH TREATED SANITARY WASTEWATER

We evaluate the application of treated sanitary wastewater (TSW) to provide potassium (K) for crops and reduce demand for fresh water and mineral nutrients. The field experiment was arranged in randomized block design with four replications and five treatments: 50, 100, 150 and 200% of K requirements and one control with conventional K fertilizer. The TSW was applied to maize (November 2012 to February 2013), cotton (June to November 2013) and bean (April to June 2014). After bean, soil chemical properties were evaluated until 0.8 m depth. Fertigation with TSW to K fertilization provides about 50% of water, nitrogen (N) and phosphorus (P) to the bean. The soil nutrient availability and soil organic matter (SOM) did not increase, whereas sodium (Na) had linear increased with TSW levels in investigated soil depth. Soil pH showed same behavior that Na, with the highest pH level of 6.5 in 0-0.2 soil layer. Soil nutrients and organic matter do not increase with TSW doses up to 0.8 m depth. Soil pH and exchangeable Na have linear increasing with TSW doses, respectively up to 0.6 and 0.8 m soil depth. Fertigation with K recommendation also provided a high content of Na, threatening the balance of soil-plant system with continuous use. Na should be the first reference to permanent wastewater reuse in agriculture.

Long-term performance of an integrated constructed wetland for advanced treatment of mixed wastewater

The aim of this study was to investigate long-term performance of a full-scale integrated constructed wetland (CW) system for advanced treatment of sanitary and industrial mixed wastewater. The system consisted of a vertical subsurface flow (VSF) CW, a free water surface (FWS) CW, and a horizontal subsurface flow (HSF) CW in series. Results from six-year operation showed that the system resulted in average removal efficiencies of 70%, 70%, 34%, 52%, 45%, 74%, 21%, 43%, and 98% for COD, NH4-N, NO3-N, TN, TP, TSS, F−, Ni, and E. coli, respectively. Especially, NH4-N was effectively removed by the VSF CW. With relatively high hydraulic loading rates (18.0–43.6cmd−1) and short hydraulic retention times (1.04–2.51 d), the removal efficiencies of the system were quite stable for most of the water quality parameters, while the removal efficiency of TN increased from 49% to 60% during the six years. The removal efficiencies of the system were generally stable with the change of seasons. This study demonstrates that the VSF+FWS+HSF CW system can be a valuable approach for advanced wastewater treatment to meet the more stringent discharge requirement.

Enzyme pretreatment of fats, oil and grease from restaurant waste to prolong septic soil treatment system effectiveness

ABSTRACTWhen a fast-food restaurant's wastewater containing fats, oil and grease (FOG) is discharged into a collection system, it builds up over time and clogs pipes. Similarly, when such wastewater flows into a septic soil treatment system, it adheres to the surface of inlet pipes, gravel/distribution media and soil, restricting the flow and eventually clogging the septic soil treatment system. In this study, an enzymatic pretreatment system was tested on wastewater from a fast-food restaurant to determine its effectiveness in preventing septic soil treatment system clogging. This system used aeration equipment, baffles and a one-time inoculum that excretes enzymes to reduce the molecular weight and number of double bonds associated with FOG. FOG containing triglycerides having lower molecular weights and fewer double bonds are less sticky. The enzymatic pretreatment system was found to cause these changes as verified by measuring the types of triglycerides (compounds in FOG) using liquid chromatography/mass spectrometry. A unique bench-scale septic soil treatment system (soil trench) was also used. Each contained six soil moisture sensors to enable the determination of moisture saturation trends among the five tested conditions: sanitary wastewater only, a combination of sanitary and kitchen wastewater, enzymatically pretreated sanitary and kitchen wastewater, kitchen wastewater, and enzymatically pretreated kitchen wastewater. For all influent types, a significant amount of FOG and other pollutants were removed, regardless of the initial concentrations. Moisture sensor readings showed differences among the tested conditions, indicating that septic soil treatment system clogging was delayed. Inspection of the influent pipe and gravel at the end of testing verified these differences as did the measurements of volatile solids.

Ozonated water in the post-harvest treatment of coffee fruits

ABSTRACT Ozone is used in many countries for the treatment of effluents, becoming a viable alternative in sanitation of coffee wastewater. However, the strong ozone oxidation, responsible for its germicidal effect, can also compromise grain and beverage quality. The objective of this study was to evaluate the quality of Arabica coffee in different periods of treatment with ozonated water and its effect after drying. Coffee fruits were subjected to ozonation at regular intervals of 0, 5, 10, 20, and 30 min, with continuous stirring promoted by a recirculating water system at constant rate of 1 ppm of solubilized ozone. The design was completely randomized with five treatments and four replicates. After obtaining the data, the analysis of variance was performed and means were compared by Tukey test (p ≤ 0.05). The results showed a partial reduction of fungi after washing with ozonated water, but the same effect was not observed after drying. For coffee quality analysis, the longest times of exposure to the solubilized gas in the water produced some negative results in electrical conductivity and total and reducing sugars. However, the sensory quality of the beverage was maintained.

Wastewater Pollution from Cruise Ships in the Adriatic Sea

The global growth of cruise tourism has brought increasing concern for the pollution of the marine environment. Marine pollution from sanitary wastewater is a problem especially pronounced on large cruise ships where the number of people on board may exceed 8,000. To evaluate future marine pollution in any selected period of time it is necessary to know the movement of ships in the Adriatic Sea. This paper presents the problem of marine pollution by sanitary wastewater from cruise ships, wastewater treatment technology and a model of cruise ship traffic in the Adriatic Sea considering MARPOL Annex IV areas of limited wastewater discharge. Using the model, it is possible to know in advance the routes of the cruisers and retention time in certain geographic areas. The data obtained by this model can be used as input parameters for evaluation model of wastewater pollution or for evaluation of other types of pollution from cruise ships.

Indicadores de produção e qualidade da fibra do algodoeiro fertirrigado com água residuária sanitária

RESUMO Problemas decorrentes da descarga de esgoto sanitário em rios são fatores preocupantes, por reduzir a qualidade da água, principalmente na região semiárida. Como alternativa viável, a utilização agrícola de águas residuárias pode minimizar problemas ambientais e fornecer nutrientes bem como parte da exigência hídrica de plantas cultivadas. Assim, objetivou-se verificar a influência da água residuária sanitária tanto na forma bruta (ARB) quanto na tratada, em nível terciário (ART), em substituição à adubação potássica mineral em cobertura, sobre os indicadores de produção e qualidade tecnológica da fibra do algodoeiro NuOpal BG RR®. O experimento foi conduzido em Janaúba - MG, no delineamento em blocos casualizados, constituído por 5 tratamentos (T0: Água limpa e adubação mineral; T1: 100% e T2: 150% de ART no fornecimento do K em cobertura; T3: 100% e T4: 150% de ARB no fornecimento do K em cobertura), com quatro repetições. Pode-se substituir a adubação potássica em cobertura aplicando 100% da dose potássica recomendada via ART, sem afetar a produtividade e a qualidade da fibra, sendo complementada a cobertura nitrogenada. Ao se empregar a ARB, além de não afetar a qualidade da fibra, há incremento de até 43,6% na produtividade do algodão, sendo dispensada a cobertura nitrogenada.

Caffeine in Boston Harbor past and present, assessing its utility as a tracer of wastewater contamination in an urban estuary

Sites throughout Boston Harbor were analyzed for caffeine to assess its utility as a tracer in identifying sources of sanitary wastewater. Caffeine ranged from 15ng/L in the outer harbor to a high of 185ng/L in the inner harbor. Inner harbor concentrations were a result of combined sewage overflow (CSO) events as well as illicit discharge of sanitary sewage into municipal storm drains. Comparing current results to data from 1998 to 1999 shows reductions in caffeine levels. Reductions are attributed to termination of effluent discharge to the harbor, declines in the number of CSOs and discharge volume along with efforts to eliminate illicit discharges. Spatial distributions of caffeine identified CSOs as major contemporary sources to the inner harbor. The findings further establish the utility of caffeine as a tracer for sanitary wastewater contamination in urban estuaries and demonstrate the efficacy of pollution reduction strategies undertaken in recent decades in Boston Harbor.