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An alternate approach to urban and regional planning is presented that considers the wastewater infrastructure from an energy consumption and carbon production perspective. The existing wastewater infrastructure from four counties in North East England region is investigated, which includes energy and carbon dioxide (CO 2 ) data from 87 wastewater treatment plants (WWTPs) (16 activated sludge (AS) and 71 biofilter (BF) plants) and 196 pump stations across the region. This study provides a rigorous and novel way of justifying new investments for retrofitting treatment technologies to the wastewater network. Mass and energy balances are performed across the network utilising a spread-sheet based model. Overall, energy use and CO 2 emissions are greatest in biological wastewater treatment (relative to other network elements) with estimated median levels of 0.37 kWh/m 3 and 0.40 kg-CO 2 /m 3 , respectively, per waste volume processed. However, energy-use and CO 2 emissions differed according to treatment technology with AS plants using significantly more energy (median = 0.4 kWh/m 3 ) and producing more CO 2 (median = 0.4 kg-CO 2 /m 3 ) than BF plants (medians: 0.2 kWh/m 3 and 0.3 kg-CO 2 /m 3 , respectively). Hence, directed interventions within WWTPs themselves will have the greatest positive influence on energy use and CO 2 emissions. Given water companies are often locked-in with their infrastructure, retrofitting existing treatment networks is strongly suggested. For example, adding BF pre-treatment to existing AS plants will reduce energy use, whereas anaerobic or photosynthetic technologies may be useful for reducing energy and CO 2 emissions in new-builds. This study confirms energy and carbon dioxide inefficiencies exist in modern wastewater networks, but uniquely identifies targeted actions to reduce inefficiencies, especially retrofitting existing WWTPs to reduce CO 2 emitted and energy used in the wastewater infrastructure to make major advances towards achieving climate change reduction targets. [ABSTRACT FROM AUTHOR]

Wet ponds have often been installed to detain runoff with the intention of mitigating peak flow. However, significant current drivers exist to improve their ability to mitigate pollutants, and simple retrofits to existing ponds could help to meet total maximum daily load regulations. A review of past studies showed that ponds struggle to treat dissolved pollutants, which are often the most bioavailable. The present study evaluated the nutrient and sediment treatment performance of a retrofitted upflow filter (UF) attached to the drawdown orifice of an existing wet retention pond in Durham, North Carolina. The pond was studied during three periods: (1) control, where baseline pond performance was established; (2) after retrofit with floating treatment wetlands (FTWs); and (3) after retrofit with FTWs and an UF on the pond's drawdown orifice. The added UF was unable to improve the pond's retention of nitrogen. Further reduction of the TSS effluent concentrations by the UF may have been hampered by the low effluent concentrations during the FTW period (13 mg=L); however, the variability of TSS effluent concentrations was substantially reduced following UF retrofit. The UF significantly reduced mean effluent concentrations of orthophosphate (OP) to less than 0.01 mg=L. Effluent concentrations of OP and total phosphorus from the UF were similar to those from bioretention systems. Clogging of the filter media occurred in intervals of 5 to 9 months prior to breakthrough of OP. Future designs of UFs should incorporate microscale pretreatment and/or filter media cartridges that (1) are easy to remove and (2) provide a method to flush accumulated sediment from the media. [ABSTRACT FROM AUTHOR]

Wastewater treatment selection is a complex task usually addressed by applying separate tools for the correct assessment of multi-criteria evaluation. Novedar_EDSS integrates technical, environmental, economic and social assessment capabilities in one single platform. The aim of this work is to evaluate and demonstrate the capabilities of this environmental decision support system (EDSS). For that purpose, 4 case studies of real projects were selected to validate the results in the EDSS by comparing them with those from the study of alternatives performed by the decision makers. Moreover, 1 conceptual case study was applied to support the selection of the most properly strategy for plant retrofitting. Results have demonstrated that the EDSS provides key aspects when deciding the retrofitting process to apply and, when compared to real projects, it recommends analogue treatments as those applied in the projects, ranking them in the same order. Therefore, results in the validation process performed show that this tool provides a reliable basis to support decision makers to select properly treatment alternatives in wastewater treatment plant pre-design. [ABSTRACT FROM AUTHOR]

Carbon capture and storage (CCS) is an attractive option to help reduce China's carbon emission. This paper analyzes the impacts of subsidy for electricity generation on CCS retrofitting investment and carbon abatement in China's coal power plants, considering the coaction of carbon market and subsidy policy. To this end, this paper builds up a real option model, considering carbon prices, electricity prices and coal prices' uncertainties. For decision of CCS investment, we consider two important aspects: whether to invest and when to invest, i.e. CCS investment's potential and timing. Some major findings include: 1) The impacts of subsidy on CCS investment and carbon abatement are affected by carbon market conditions: initial carbon price can determine the magnitude of subsidy's impacts, while carbon prices' uncertainty level can determine subsidy's marginal impacts. 2) Subsidy from $0.01 to $0.05/kWh can raise CCS investment potential by 9.66%–39.18%, shorten CCS investment period by 0.39–1.95 years and bring carbon abatement potential of 0.10–1.89 GtCO 2 , considering different carbon market conditions. 3) With the benchmark carbon market and affordable subsidies, triggered CCS investments in coal power plants have an economical-efficient carbon abatement potential up to 20% of China's carbon emission in 2030. [ABSTRACT FROM AUTHOR]

Retrofitting existing wastewater treatment plants has become a major challenge in the wastewater engineering area, in particular due to the increasing number of competing technologies and concepts (treatment versus resource problem). In order to support the expert-based approach and provide a rational design for WWTPs, we proposed the use of a mathematical programming based framework to manage the complexity and solve the multi-criteria retrofitting problem. The treatment alternatives were represented in a superstructure – coupled with a database containing information on performance and economics of treatment units. The optimization problem was solved for different objective functions and constraints corresponding to different retrofitting scenarios. The framework was evaluated on two full-scale domestic wastewater treatment plants (265,000 PE and 750,000 PE respectively). To this end, the design space included 9 side-stream treatment technologies and 9 main line technologies resulting in more than 200 retrofitting alternatives. The retrofitting problem resulted in the selection of a high-rate oxic reactor coupled with anammox technology in the main line as the optimal solution, due to the low utility consumption and high biogas production associated with this network. On the other hand, most of the side stream treatment alternatives have similar technical–economic benefits in terms of the whole plant retrofitting cost function. Therefore the selection of the optimal alternative is more based on local conditions and preferences in that case. [ABSTRACT FROM AUTHOR]

Retrofitting of existing buildings plays a critical role to achieve sustainable development. There are a number of factors that affect the effectiveness of building energy efficient retrofitting. These factors can be broadly categorised as technology and management. A case study approach was employed in this study to examine effective ways of building energy efficient retrofitting based on one year of monitoring. Several feasible schemes of building energy efficient retrofitting were identified according to the characteristics of the case building. The best scheme was chosen according to results of simulation, comparison and analysis. The focuses of building energy efficient retrofitting were placed on energy conservation and indoor environment quality. In particular, during the operation stage, staff can regulate the terminal unit in accordance with their own demands. Results showed that the building operation can satisfy staff's individual requirements after the retrofit. Similarly, the annual energy consumption can be reduced by 57% compared to the national average of office buildings in China. These findings provide useful inputs for the future building energy efficient retrofitting practices as well as policy making process. [ABSTRACT FROM AUTHOR]

A systematic retrofitting methodology supported by real data implementation was developed to facilitate the optimization of pharmaceutical drug purification processes. The methodology consists of five tasks: (I) understand the plant through measurements, (II) create a process model, (III) adapt the model for optimization, (IV) optimize the process model, and (V) interpret the outcome of the task. A novelty of this methodology is the use of path-flow decomposition as a tool to provide a visual representation of the process, thus facilitating its understanding and the creation of the process model. Furthermore, a decision-tree diagram furnishes detailed and specific support during the creation of the process model, in particular for a dissolution–filtration–crystallization process. Identification of constraints and optimization variables ensure the applicability of the methodology to pharmaceutics. Incorporation of measured process data improves the reliability of the methodology, making it applicable in real case studies. The methodology was applied to an industrial case study. [ABSTRACT FROM AUTHOR]

This paper presents a generic mathematical model for retrofitting the steam power plants in an industrial site. The industrial sector under review consists of one steel mill, one oil refinery, and several petrochemical plants, where only small-scale steam integration has been implemented before this study. The relevant unit models in a typical steam power plant are established, and the steam plant retrofit problem is formulated as a mixed-integer nonlinear program (MINLP). Feasible retrofit alternatives suggested by experienced field engineers are investigated in sequence to examine the revenue of those possible modifications. The first scenario examines operational optimization of existent plants; the second option allows installation of one new turbine and replacement of several boilers and turbines with lower efficiency; the third scenario considers using a steam ejector to upgrade the disqualified import steam in the oil refinery. The significant merits from these three retrofit alternatives show that the proposed MINLP formulation has been a great help to enhance the inter-plant steam integration in an industrial sector. [ABSTRACT FROM AUTHOR]

Experience of retrofitting sustainable drainage systems ( SuDS) in the United Kingdom is limited, and there are no well-established procedures for evaluating the feasibility, value or cost-effectiveness of doing this, particularly at the catchment scale. This paper demonstrates a two-phase process for evaluating the potential to retrofit SuDS to address combined sewer discharges in three subcatchments within the Thames Tideway catchment of London. The first phase evaluates what might be achieved with various levels of disconnection ('global' disconnection scenarios) using hydraulic models, while the second phase considers how disconnection might practically be achieved. High levels of disconnection are technically possible but practicably difficult. In selected cases, and with aggressive implementation of SuDS, combined sewer overflow CSO discharges could potentially be eliminated or reduced to acceptable levels without the need for any modifications to underground assets. However, retrofit SuDS could not eliminate the requirement for some form of sewer modification in any subcatchments. [ABSTRACT FROM AUTHOR]

Great efforts have been made in China to retrofit and upgrade the existing municipal wastewater treatment plants (WWTPs) for enhanced removal of organic substrates and in particular nutrients. However, the removal of trace recalcitrant or hazardous organic chemicals, e.g. steroid estrogens, one group of typical endocrine disrupting chemicals, has long been overlooked. The extensive investigations on estrogen removal rates in global and Chinese WWTPs and the estrogen biodegradation kinetics results in batch laboratory experiments are reviewed in this study. The effects of estrogen initial concentration and nitrifying activated sludge are highlighted. Challenges existing in current estrogen studies are pointed out, which are relevant for researches on fate and behavior of similar down-the-drain chemicals in both Chinese and global WWTPs. [Copyright &y& Elsevier]

The urban-water cycle modifies natural stream hydrology, and domestic and commercial activities increase the burden of endocrine-disrupting chemicals, such as steroidal hormones and 4-nonylphenol, that can disrupt endocrine system function in aquatic organisms. This paper presents a series of integrated chemical and biological investigations into the occurrence, fate, and effects of endocrine-disrupting chemicals in the City of Boulder Colorado's WWTF and Boulder Creek, the receiving stream. Results are presented showing the effects of a full-scale upgrade of the WWTF (that treats 0.6 m3 s-1 of sewage) from a trickling filter/solids contact process to an activated sludge process on the removal of endocrine-disrupting compounds and other contaminants (including nutrients, boron, bismuth, gadolinium, and ethylenediaminetetraacetic acid) through each major treatment unit. Corresponding impacts of pre- and postupgrade effluent chemistry on fish reproductive end points were evaluated using on-site, continuous-flow experiments, in which male fathead minnows (Pimephales promelas) were exposed for 28 days to upstream Boulder Creek water and WWTF effluent under controlled conditions. The upgrade of the WWTF resulted in improved removal efficiency for many endocrine-disrupting chemicals, particularly 17β-estradiol and estrone, and fish exposed to the postupgrade effluent indicated reduction in endocrine disruption relative to preupgrade conditions. [ABSTRACT FROM AUTHOR]

This article presents a procedure to quantify the process for selecting the most advantageous technique, and also a practical method for specifying and prioritising a criterion and goals for seismic retrofitting of a building, which is developed in three steps. The first step involves recognising different parameters influenced by the efficiency of a technique and their categorisation. Then, a quantitative approach is developed to measure the relative advantages of different retrofitting options. Finally, a survey is conducted and some experts' opinions are gathered from some leading authorities, both from academia and the profession, to calibrate the method. As a case study, the procedure is applied to compare different retrofitting techniques for a vulnerable school building. [ABSTRACT FROM AUTHOR]

The design criteria for wastewater treatment plants (WWTP) and the sludge retention time, respectively, have a significant impact on micropollutant removal. The upgrade of an Austrian municipal WWTP to nitrogen removal (best available technology, BAT) resulted in increased elimination of most of the analyzed micropollutants. Substances, such as bisphenol-A, 17α-ethinylestradiol and the antibiotics erythromycin and roxithromycin were only removed after the upgrade of the WWTP. Nevertheless, the BAT was not sufficient to completely eliminate these compounds. Thus, a pilot scale ozonation plant was installed for additional treatment of the effluent. The application of 0.6 g O3 g DOC−1 increased the removal of most of the micropollutants, especially for compounds that were not degraded in the previous biological process, as for example carbamazepine and diclofenac. These results indicated that the ozonation of WWTP effluent is a promising technology to further decrease emissions of micropollutants from the treatment process. [Copyright &y& Elsevier]

In this study, a novel membrane bioreactor (MBR) in which nitrification and denitrification simultaneously proceed in a single reaction chamber is proposed for advanced municipal wastewater treatment. Anoxic/aerobic environments are alternatively created in the proposed MBR by inserting baffles inside the membrane chamber. The performance of the proposed baffled membrane bioreactor (BMBR) was examined at an existing municipal wastewater treatment facility based on long-term operation. Although the procedure was simple, insertion of the baffles actually created the alternative anoxic/aerobic environments in the chamber at a constant interval and showed a great improvement in the nutrient removal. The insertion did not cause any adverse effect on membrane permeability. In this study, almost complete elimination of NH4+-N was observed while around 8 mg/L of NO3--N was detected in the treated water. The modification proposed in this study can immediately be applied to most existing MBRs and is highly recommended for more efficient wastewater treatment. [ABSTRACT FROM AUTHOR]

The effect of retrofitting an existing pond on removal efficiency and hydraulic performance was modelled using the commercial software Mike21 and compartmental modelling. The Mike21 model had previously been calibrated on the studied pond. Installation of baffles, the addition of culverts under a causeway and removal of an existing island were all studied as possible improvement measures in the pond. The subsequent effect on hydraulic performance and removal of suspended solids was then evaluated. Copper, cadmium, BOD, nitrogen and phosphorus removal were also investigated for that specific improvement measure showing the best results. Outcomes of this study reveal that all measures increase the removal efficiency of suspended solids. The hydraulic efficiency is improved for all cases, except for the case where the island is removed. Compartmental modelling was also used to evaluate hydraulic performance and facilitated a better understanding of the way each of the different measures affected the flow pattern and performance. It was concluded that the installation of baffles is the best of the studied measures resulting in a reduction in the annual load on the receiving lake by approximately 8,000 kg of suspended solids (25% reduction of the annual load), 2 kg of copper (10% reduction of the annual load) and 600 kg of BOD (10% reduction of the annual load). [ABSTRACT FROM AUTHOR]

Textile industries carry out several fiber treatments using variable quantities of water, from five to forty times the fiber weight, and consequently generate large volumes of wastewater to be disposed of. Membrane Bio-reactors (MBRs) combine membrane technology with biological reactors for the treatment of wastewater: micro or ultrafiltration membranes are used for solid-liquid separation replacing the secondary settling of the traditional activated sludge system. This paper deals with the possibility of realizing a new section of one existing WWTP (activated sludge + clariflocculation + ozonation) for the treatment of treating textile wastewater to be recycled, equipped with an MBR (76 l/s as design capacity) and running in parallel with the existing one. During a 4-month experimental period, a pilot-scale MBR proved to be very effective for wastewater reclamation. On average, removal efficiency of the pilot plant (93% for COD, and over 99% for total suspended solids) was higher than the WWTP ones. Color was removed as in the WWTP. Anionic surfactants removal of pilot plant was lower than that of the WWTP (90.5 and 93.2% respectively), while the BiAS removal was higher in the pilot plant (98.2 vs. 97.1). At the end cost analysis of the proposed upgrade is reported. [ABSTRACT FROM AUTHOR]

The recycle water from sludge processing in municipal wastewater treatment plants causes many serious problems in the efficiency and stability of the mainstream process. Thus, the design approach for recycle water is an important part of any biological nutrient removal system design when a retrofit technology is required for upgrading an existing plant. Moreover, the application of nitrogen removal from recycle water using the nitritation process has recently increased due to economic reasons associated with an effective carbon allocation as well as the minimization of aeration costs. However, for the actual application of recycle water nitritation, it has not been fully examined whether or not additional volume would be required in an existing plant. In this paper, the addition of recycle water nitritation to an existing plant was evaluated based on a volume analysis and estimation of final effluent quality. It was expected that using the reserve volume of the aeration tank in existing plants, recycle water nitritation could be applied to a plant without any enlargement. With the addition of recycle water nitritation, it was estimated that the final effluent quality would be improved and stabilized, especially in the winter season. [ABSTRACT FROM AUTHOR]

A European sewage treatment works was experiencing problems with constant blockages and leaking glands. Access difficulties meant that maintenance costs were high. The installation of Vaughan Chopper Pumps achieved significant savings on labour and electricity consumption. Later, retrofitting proved to be self financing with payback within a year. [Copyright &y& Elsevier]

The article focuses on the improvement of the Colombia, Missouri-based wastewater treatment plant (WWTP) which will enable the city to manage the growing wastewater treatment demand more efficiently while enhancing the quality of treated water discharged into nearby wetlands. The upgrade to improve reliability and reduce energy consumption of the WWTP was designed by Black & Veatch. Funded by the U.S. American Recovery and Reinvestment Act of 2009, the project will be completed in 2012.