Wastewater Conveyance Research Articles

Greywater use in Israel and worldwide: Standards and prospects

Water shortage around the world enhanced the search for alternative sources. Greywater (GW) can serve as a solution for water demands especially in arid and semi-arid zones. However, issues considered which include acceptability of GW segregation as a separate water treated stream, allowing its use onsite. Consequently, it is the one of next forthcoming water resources that will be used, primarily in the growing mega-cities. It will be even more rentable when combined with the roof runoff water harvesting and condensing water from air-conditioning systems. Reuse of GW is as well beneficial in the mega-cities subject to the high expenses associated with wastewater and fresh water conveyance in the opposite direction. The main problem associated with GW reuse is the quality of the water and the targeted reuse options. At least two main options can be identified: the public sector that is ready to reuse the GW and the private sector which raises extra issues related to the reuse risks. These risk stems from the on yard use of GW, relatively close to the household location.The main focus of the Israeli guidelines for GW use is on the private and single house. The problem is less rigorous in public facilities, where the amounts are relatively large and the raw GW is relatively diluted. The two main principles adopted for reuse are: (i) greywater can be minimally treated since it differs from the black wastes, and; (ii) no contact exists with the resident around. The aggravated standards are an indication of the sensitivity issues related to the problem.

Prediction of CO<sub>2</sub> and H<sub>2</sub>S Emissions from Wastewater Wet Wells

The transportation of wastewater through sewer networks can cause potential problems due to the formation of lethal gases such as ammonia, carbon dioxide, hydrogen sulphide and methane. As a result, they can cause irritating, toxic, and microbial induced corrosion. The true depth of these problems can be measured by measuring the emission of such lethal gasses in the sewer atmosphere. The amount of gases released from such sewer networks has to be controlled. In this paper, we present a simple experimental methodology used to determine the emissions of Carbon Dioxide (CO2) and Hydrogen Sulphide (H2S) using Landtec GEM-2000 plus multi-gas analyser from wastewater wet wells.

Review of cost versus scale: water and wastewater treatment and reuse processes

The US National Research Council recently recommended direct potable water reuse (DPR), or potable water reuse without environmental buffer, for consideration to address US water demand. However, conveyance of wastewater and water to and from centralized treatment plants consumes on average four times the energy of treatment in the USA, and centralized DPR would further require upgradient distribution of treated water. Therefore, information on the cost of unit treatment processes potentially useful for DPR versus system capacity was reviewed, converted to constant 2012 US dollars, and synthesized in this work. A logarithmic variant of the Williams Law cost function was found applicable over orders of magnitude of system capacity, for the subject processes: activated sludge, membrane bioreactor, coagulation/flocculation, reverse osmosis, ultrafiltration, peroxone and granular activated carbon. Results are demonstrated versus 10 DPR case studies. Because economies of scale found for capital equipment are counterbalanced by distribution/collection network costs, further study of the optimal scale of distributed DPR systems is suggested.

A study on the migration and transformation law of nitrogen in urine in municipal wastewater transportation and treatment

Many studies suggest that the total nitrogen (TN) in urine is around 9,000 mg/L and about 80% of nitrogen in municipal wastewater comes from urine, because nitrogen mainly occurs in the form of urea in fresh human urine. Based on this fact, the study on the migration and transformation law of nitrogen in urine and its influencing factors was carried out. It can be seen from the experimental results that the transformation rate of urea in urine into ammonia nitrogen after standing for 20 days is only about 18.2%, but the urea in urine can be hydrolyzed into ammonia nitrogen rapidly after it is catalyzed directly with free urease or indirectly with microorganism. Adding respectively a certain amount of urease, activated sludge and septic-tank sludge to urine samples can make the maximum transformation rate achieve 85% after 1 day, 2 days and 6 days, respectively. In combination with some corresponding treatment methods, recycling of nitrogen in urine can be achieved. The results are of great significance in guiding denitrification in municipal wastewater treatment.

Exploring urban mines: pipe length and material stocks in urban water and wastewater networks

Networks for water and wastewater transport represent large capital assets and material stocks within cities. A better understanding of how their material content changes with population and size of the city may help to design networks with lower resource demand and lower construction and maintenance costs. We estimated the total length and mass for the wastewater networks of 25 cities in five different countries using a fractal network model that only requires the cities' size and population as input data. We found that most of the network mass is concentrated in the main trunk lines. The model results showed efficiency of scale: For a catchment area of constant size, both network length and mass per capita would decline if population grew. However, if the population of a city grew while the population density remained constant or decreased (urban sprawl), the per-capita network mass would increase.

Olive-oil mill wastewater transport under unsaturated and saturated laboratory conditions using the geoelectrical resistivity tomography method and the FEFLOW model

An integrated approach for monitoring the vertical transport of a solute into the subsurface by using a geophysical method and a simulation model is proposed and evaluated. A medium-scale (1 m3) laboratory tank experiment was constructed to represent a real subsurface system, where an olive-oil mill wastewater (OOMW) spill might occur. High-resolution cross-hole electrical resistivity tomography (ERT) was performed to monitor the OOMW transport. Time-lapse ERT images defined the spatial geometry of the interface between the contaminated and uncontaminated soil into the unsaturated and saturated zones. Knowing the subsurface characteristics, the finite element flow and transport model FEFLOW was used for simulating the contaminant movement, utilizing the ERT results as a surrogate for concentration measurements for the calibration process. A statistical analysis of the ERT measurements and the corresponding transport model results for various time steps showed a good agreement between them. In addition, a sensitivity analysis of the most important parameters of the simulation model (unsaturated flow, saturated flow and transport) was performed. This laboratory-scale study emphasizes that the combined use of geophysical and transport-modeling approaches can be useful for small-scale field applications where contaminant concentration measurements are scarce, provided that its transferability from laboratory to field conditions is investigated thoroughly.

Methane Evolution from Wastewater Conveyance

Methane (CH4) production from sewers is a suspected, yet relatively undocumented source of greenhouse gases (GHGs). The Intergovernmental Panel on Climate Change (IPCC) published the 2006 IPCC Guidelines for National Greenhouse Gas Inventories which states that In most developed countries and in high-income urban areas in other countries, sewers are usually closed and underground. Wastewater in closed underground sewers is not believed to be a significant source of CH4. CH4 is a greenhouse gas that has a global warming impact that is 21 times that of carbon dioxide (CO2) and as such is of heightened interest in GHG modeling and inventories. Phase 1 of this project entailed instantaneous methane emissions measurements at 64 raw sewage lift stations throughout the collection system in the DeKalb County, Georgia. During Phase 2 of this project, continuous gaseous- and liquid-phase monitoring were conducted at the discharge of a 16-inch, 3.3-mile-long force main from the Honey Creek Pumping Station. Liquid phase sampling during this phase showed that 8.87 kg of CH4 were emitted per day at the force main receiving manhole during the summer months. The continuous monitoring data was used to calibrate a process model developed by the University of Queensland to predict CH4 and hydrogen sulfide evolution by simulating a force main as a plug-flow, fixed-film reactor. The model was then used to simulate force main CH4 emissions over a calendar year using historical flow and monthly average temperatures. This effort calculated emissions of 52 MT of CO2e/year. Overall this exploratory research project provides following benefits and outcomes. This title belongs to WERF Research Report Series . ISBN: 9781780404691 (eBook)

Flare Efficiency Estimator and Case Studies

A flare efficiency estimator (FEE) tool is part of Water Environment Research Foundation (WERF) project U2R08 entitled Methane Evolution from Wastewater Treatment and Conveyance under WERF's Climate Change Program and funding from the New York State Energy Development Authority (NYSERDA). The FEE is based on the work of the Flare Research Group at the University of Alberta (UoA) and it will help estimate the fugitive greenhouse gas (CH4) emissions from the unprotected ‘candlestick’ flares for digester gas and landfill gas flares. FEE is available online for free and can be obtained from this NYSERDA webpage: . This title belongs to WERF Research Report Series . ISBN: 9781780404882 (eBook)

Inhibitory effects of sulfide on nitrifying biomass in the anaerobic–anoxic–aerobic wastewater treatment process

AbstractBACKGROUNDLong pipeline transportation of wastewater usually generates high concentration of sulfide; however, information on nitrification inhibition by sulfide in the anaerobic–anoxic–aerobic (AAO) process is still scarce. This study focused on how sulfide could inhibit nitrification activity in the AAO process, and the inhibitory effect of initial sulfide concentration and anaerobic exposure time on the behavior of nitrifying biomass.RESULTSThe net maximum specific growth rate (μAUT‐bAUT) was, respectively, 0.06 ± 0.01 and 0.31 ± 0.03 d−1 at 15 and 20°C in a full‐scale AAO wastewater treatment plant for long‐pipeline transported wastewater. The μAUT‐bAUT was not affected by 6.2 mg L−1 sulfide under aerated condition, but reduced by 75.9% after unaerated exposure for 0.5 h. The first‐order kinetic constant of sulfide inhibition under anaerobic conditions was 0.658 h−1, and half maximal inhibition concentration of sulfide on nitrification was 36.0 and 10.0 mg L−1 after 1.0 h and 1.5 h anaerobic exposure, respectively.CONCLUSIONNitrifying biomass was sensitive to the presence of sulfide under anaerobic conditions. The inhibitory reaction of sulfide on nitrifying biomass under anaerobic conditions conformed to the first‐order kinetic reaction, while the effect of initial sulfide concentration on nitrification inhibition matched the modified Monod model. © 2013 Society of Chemical Industry

Urban net-zero water treatment and mineralization: Experiments, modeling and design

Water and wastewater treatment and conveyance account for approximately 4% of US electric consumption, with 80% used for conveyance. Net zero water (NZW) buildings would alleviate demands for a portion of this energy, for water, and for the treatment of drinking water for pesticides and toxic chemical releases in source water. However, domestic wastewater contains nitrogen loads much greater than urban/suburban ecosystems can typically absorb. The purpose of this work was to identify a first design of a denitrifying urban NZW treatment process, operating at ambient temperature and pressure and circum-neutral pH, and providing mineralization of pharmaceuticals (not easily regulated in terms of environmental half-life), based on laboratory tests and mass balance and kinetic modeling. The proposed treatment process is comprised of membrane bioreactor, iron-mediated aeration (IMA, reported previously), vacuum ultrafiltration, and peroxone advanced oxidation, with minor rainwater make-up and H2O2 disinfection residual. Similar to biological systems, minerals accumulate subject to precipitative removal by IMA, salt-free treatment, and minor dilution. Based on laboratory and modeling results, the system can produce potable water with moderate mineral content from commingled domestic wastewater and 10–20% rainwater make-up, under ambient conditions at individual buildings, while denitrifying and reducing chemical oxygen demand to below detection (<3 mg/L). While economics appear competitive, further development and study of steady-state concentrations and sludge management options are needed.

Modeling of transport and transformation of synthetic wastewater in irrigated soils

Scarcity of fresh water has led to use of low quality waters that were considered unsuitable for irrigation in the past. Mismanagement of irrigation with wastewater poses risks to deterioration of the hydraulic soil properties and pollution of groundwater. In order to study these concerns, synthetic wastewater was poured on steady-state flux one-dimensional aerobic sand columns and the results were analyzed. Four irrigation treatments with different levels of chemical oxygen demand (COD) were performed as a randomized complete block design with three replicates. Soil water content, electrical conductivity, water potential, and hydraulic conductivities were monitored. The CXTFIT code was used to inversely determine degradation constant and the transport parameters of the convective–dispersive equation (CDE). In all treatments the hydraulic transport properties remained constant. Conversely, the first-order kinetics degradation constant decreased in an identical way for all COD treatments. It is also concluded that if a primary treatment removes the solids, which is essential for drip irrigation, domestic wastewater, similar to our synthetic water and without toxic or pathogen elements, poses few risks for groundwater pollution.

Generation, transport, and disposal of wastewater associated with Marcellus Shale gas development

Key Points First comprehensive estimates of wastewater from Marcellus shale gas wells Marcellus wells produce less wastewater per unit gas than conventional wells Cumulative Marcellus wastewater volume may soon overwhelm disposal capacity

Evaluation of Water Quality Management Alternatives to Control Dissolved Oxygen and Un-ionized Ammonia for Ravi River in Pakistan

Different water quality management alternatives, including conventional wastewater treatment, transportation of wastewater, flow augmentation, low-cost treatment with reuse, and wetlands, are evaluated by using a verified dissolved oxygen (DO) model for the Ravi River. Biokinetic rate coefficients of the Ravi River for both the carbonaceous and nitrogenous oxygen-demanding wastes are adjusted, keeping in view the type and level of wastewater treatment. The conventional activated sludge process with nitrification comes out to be the most expansive alternative to meet the DO standard of 4 mg/L. Additional treatment cost is required to maintain un-ionized ammonia levels <0.02 mg/L, which corresponds to achieving treatment levels of 5 mg/L of DO in the river. Under critical low-flow conditions (i.e., minimum average seven consecutive days) of 9.2 m3/s, a flow augmentation of 10 m3/s can reduce 30 % of the cost with conventional wastewater treatment. Transportation of wastewater from the city of Lahore is a cost-effective alternative with 2.5 times less cost than the conventional process. Waste stabilization ponds (WSP) technology is a low-cost solution with 3.5 times less cost as compared to the conventional process. Further reduction in pollution loads to the Ravi River can be achieved by reusing WSP effluents for irrigation in the near proximity of Lahore along the Ravi River. The study results show that, for highly polluted rivers with such extreme flow variations as in case of the Ravi River, meeting un-ionized ammonia standards can reduce the efforts required to develop carbonaceous biochemical oxygen demand-based waste load allocations.

Studies on biodegradation of vegetable-based fat liquor-containing wastewater from tanneries

Fat liquoring, a post-tanning operation is carried out on tanned leather using oils, fats, or greases in emulsion form to make soft leathers and to improve the physical characteristics of the finished products during leather manufacturing. Around 10–15 % of un-exhausted fat liquor is discharged in the process water as wastewater. The major components of vegetable fat liquor are triacylglycerols, which primarily consist of glycerol molecules esterified with long chain fatty acids. The presence of fats, grease, and oils not only causes choking of wastewater conveyance mains but also interferes with the oxygen-transfer efficiency in aerobic treatment process. The aim of the present study is to assess the rate of biodegradability of vegetable-based fat liquor-containing wastewater generated from tanneries for various food to microbial (f/m) ratio, i.e., 0.35, 0.25, and 0.15 g biochemical oxygen demand (BOD5)/g volatile suspended solids (VSSs) day. The f/m ratio and reaction time were investigated in detail in aerobic batch reactor to arrive at the optimum ratio needed for biodegradation of vegetable fat liquor. From the aerobic biodegradation studies, it was established that at an f/m ratio of 0.15 and a reaction time of 24 h, BOD5 and chemical oxygen demand removals were 97.24 and 89.58 %, respectively. It was evident from Fourier transform infrared spectrometry and electrospray ionization–mass spectroscopy analysis that the triglycerides present in vegetable fat liquor were degraded effectively.

Abu Dhabi's strategic tunnel enhancement programme: odour extraction system approaches

The Emirate of Abu Dhabi has experienced tremendous growth since the mid-1970s resulting in significant overloading of its existing sewerage system. Master planning determined that the best long-term wastewater collection and conveyance solution was construction of a deep tunnel sewer system. Implementation of this massive project faced numerous challenges, including the goal of no odours and limited odour control facilities. To accomplish this, the consultant team examined a unique approach of a single odour control system installed at the proposed downstream tunnel pumping station. Rigorous analysis utilising computer-based models confirmed the viability of this approach. However, other approaches including multiple satellite (localised or regional) odour extraction systems were considered. To better understand entrained air forces at vortex drops, and to confirm the preferred odour extraction approach, physical modelling of drop structures and overall tunnel system was implemented. Results and findings concluded that a regional odour extraction system approach was preferred over a single (centralised) extraction approach. This paper focuses on the process of selecting the preferred odour extraction approach and preliminary capacity sizing of regional systems.

Behavior and effect of manufactured nanomaterials in the marine environment

Estuary and coastal environments are a ‘‘sink’’ for contaminants, including manufactured nanomaterials (MNMs) (Klaine et al. 2008). MNMs may enter the marine environment via rainwater, wastewater, and river transportation. Harbor handling may also result in MNM leakage and deposition in harbor areas. Dumping wastes such as nanowaste, trash containing MNMs, and harbor-dredging, mudcontaining MNMs into the sea, atmospheric sedimentation, and others may all cause MNMs to enter the marine environment. Compared to those in fresh water, MNMs in marine environments may demonstrate different environmental behavior and effects. MNMs in a marine environment are less stable and more easily sink out of the water column than those in a freshwater environment. Multiwalled C nanotubes (MWCNTs) can disperse into an aqueous suspension in natural surface freshwater and remain stable for as long as 1 month after stirring (Hyung et al. 2007). However, we have found that MWCNTs sink to the bottom rapidly in seawater. Fullerene (C60) forms a faint yellow aqueous suspension in various experimental waters after stirring or with the assistance of a cosolvent that can remain stable for several weeks or months. This C60 aqueous suspension quickly sinks in seawater with 20% salinity; the sedimentation rate reaches 29% after mixing for 1 h (Blickley and McClennan-Green 2008). We similarly added C60 to neutral seawater, which was then stirred continuously. Although C60 formed a faint yellow suspension, it remained stable for only 48 h (Zhu and Cai 2011). Nanoscale titanium dioxide particles (nTiO2), zinc oxide particles (nZnO), and cerium oxide particles (nCeO2) were relatively stable in freshwater, and more than 90% of these nanomaterials remained in the water body even after standing for 6 h at 200mg/L concentrations (Keller et al. 2010). However, in seawater, less than 30% of them remained after 6 h. Consequently, the benthic ecosystem in those areas receiving elevated water column levels of MNMs may be affected. MNMs are more apt to agglomerate in larger average particle diameters in seawater than in freshwater. For example, nTiO2 rapidly agglomerates in seawater, and the average particle diameter of the agglomeration significantly increases with increased nTiO2 concentration and sedimentation time. At 10mg/L nTiO2, the agglomeration particle diameter rapidly increases from below 500nm to 1000 nm within 30min. At higher nTiO2 concentrations, the diameter rapidly increases from below 1000 nm to above 2000 nm within 30min (Keller et al. 2010). However, after entering freshwater, the average particle diameter of nTiO2 agglomeration is only slightly higher than 300 nm, which is far lower than the value in seawater. The diameter does not significantly change with increased nTiO2 concentration and sedimentation time within 6 h (Keller et al. 2010). The electric potential, electrophoretic mobility, and solubility of nanomaterials differ in freshwater and seawater. The electric potential of nTiO2 in natural seawater fluctuated between 0.0282 and 0.0148mV, whereas nTiO2 appeared relatively stable in natural freshwater. The electric potential of 15.88mV was obviously lower than that in seawater (Zhu and Cai 2011). The electrophoretic mobility of nTiO2 ( 2.40mm/s/V) in natural freshwater was also lower than that in seawater ( 0.04mm/s/V) (Keller et al. 2010). Moreover, approximately 3.5mg/L Zn2þ was released from 80mg/ L nZnO dissolved in seawater (Miller et al. 2010). In contrast, over 15mg/L Zn2þ was released from 100mg/L nZnO dissolved in freshwater (Franklin et al. 2007). The reason for this difference is unknown. Studies on the toxic effects of MNMs in marine species are limited. Toxicity of MNMs has everything to do with the category, concentration, particle diameter, suspension preparation method, and solubility in seawater of MNMs. Compared with those in freshwater, the different properties of MNMs in seawater may cause different toxic effects and mechanisms. For example, the mechanism of action of nZnO in freshwater green algae may be mainly by the Zn2þ it releases (Franklin et al. 2007). However, because the Zn2þ released by nZnO in seawater is less bioavailable than in freshwater, the toxic effects of nZnO in marine algae may be the compound toxic effects of nanoparticles and metal ions (Miller et al. 2010). nAg is widely used as an antibacterial agent, but it fails to have a significant influence on the diversity of natural bacterial colonies in river mouth sediments (Bradford et al. 2009). nTiO2 at concentrations up to 500mg/L was not acutely toxicity to zebrafish embryos in freshwater, but 10mg/L nTiO2 significantly reduced embryo hatching and increased the malformation rate of the abalone Haliotis diversicolor supertexta in seawater (Zhu et al. 2011). The possible ecological effects of MNMs in the marine environment should not be ignored. Acknowledgment—This study was supported by the National Natural Science Foundation of China (21107058), the Doctoral Education Funding of the Education Ministry of China (20100002120019), the Natural Science Foundation of Guangdong Province of China (S2011010005391), and the Basic Research Project of the SZSITIC Commission of Shenzhen, China (JC201005270289A).

Demonstration and evaluation of an innovative water main rehabilitation technology: Cured-in-Place Pipe (CIPP) lining

As many water utilities are seeking new and innovative rehabilitation technologies to extend the life of their water distribution systems, information on the capabilities and applicability of new technologies is not always readily available from an independent source. The U.S. Environmental Protection Agency (EPA) developed an innovative technology demonstration program to meet this need. The purpose of the demonstration program is to evaluate rehabilitation technologies that have the potential to reduce costs and increase the effectiveness of the operation, maintenance, and renewal of aging water distribution and wastewater conveyance systems. This paper provides an impartial assessment of the effectiveness and cost of a cured-in-place pipe (CIPP) lining technology for water main rehabilitation. This project demonstrated an innovative Class IV rehabilitation technology that met the project requirements and as part of the evaluation, multiple utilities expressed their willingness to use the technology in the future. The demonstration provided valuable information on the design, installation, and QA/QC of CIPP used to rehabilitate water mains, and makes recommendations for continued improvements in the process used for internal reinstatement of services. One issue that requires more study is the effect of pre-rehabilitation cleaning process on the service connection reinstatement process. Other issues contributing to the need for external reinstatement that should be studied and improved upon include: flush service connections that cannot be identified in smaller diameter pipes and difficulty drilling service connections located in folds.

Healthy communities

There is considerable knowledge of how to enhance the health of communities through reshaping their environments, particularly the urban environments in which people increasingly live. We have much less understanding of how to deliver these healthier urban environments. This paper reviews the research on four key urban health problematics – sanitation and wastewater treatment, transportation and mobility, the urban heat island impacts, and indoor air quality – and considers the implications for urban planning and management.

Healthcare Facility Effluents as Point Sources of Select Pharmaceuticals to Municipal Wastewater

Effluents from four healthcare facilities were characterized for the concentration of 16 common active pharmaceutical ingredients. The sampled facilities included a hospital, nursing care, assisted living, and independent living facility located within a single municipal wastewater system in Texas. Eleven of the 16 monitored pharmaceuticals were detected in at least 1 healthcare facility effluent and 2 measured antibiotics (sulfamethoxazole and trimethoprim) were detected in all 4 facility effluents. Active pharmaceutical ingredient concentrations ranged from non-detectable levels for several corticosteroids in all facility effluents to 180 microg/L sulfamethoxazole in the nursing care wastewater effluent. The mass of active pharmaceutical ingredients discharged to the municipality's wastewater conveyance system was determined by combining individual facility concentration data and daily wastewater flow. The estimated daily mass loading of all 16 pharmaceuticals ranged from 0.16 g/day to 23 g/day in the assisted living facility and nursing wastewater effluents, respectively. The combined active pharmaceutical ingredient mass loading for all four facilities was 42.6 g/day. These findings provide source characterization data for 16 common pharmaceuticals in healthcare facility wastewater and provide a basis for risk assessment of pharmaceuticals present in healthcare facility wastewaters.

Hydrochemical characteristics and water quality of the Mušnica River catchment, Bosnia and Herzegovina

The spatial position of the Mušnica River catchment in the Dinaric Karst results in specific conditions of the drainage, distribution and chemical characteristics of the surface water and groundwater. This catchment is mountainous, located between 930 and 1985 m above sea level. The chemical characteristics of the waters are strongly dependent on the local lithological composition and the precipitation regime. The dominant cations are Ca2+ and Mg2+, and anions HCO3 - and SO4 2-. The surface water is characterized by low and medium mineralization, with resultant soft, medium-hard and very-hard total hardness levels. The groundwater is more mineralized than the surface water. Gacko Town and its associated thermal power plant, Gacko 1, which are located in the southern part of the Mušnica River catchment, have no modern facilities for sewage and wastewater transport or treatment. In order to prevent further water quality deterioration and to enable its sustainable use, it is recommended to ensure adequate protection measures in the catchment area. Editor Z.W. Kundzewicz; Associate editor S. Faye Citation Banjak, D. and Nikolić, J., 2012. Hydrochemical characteristics and water quality of the Mušnica River catchment, Bosnia and Herzegovina. Hydrological Sciences Journal, 57 (3), 562–575.