Use of industrial wastewaters for the optimization and control of nitrogen removal processes.

In this experimental study the characterization of 2 industrial wastewaters, coming from an ice cream production industry (IW1) and a beet-sugar factory (IW2), with respect to their readily biodegradable fraction and denitrification potential, has been performed. To this end physical-chemical and biological characterization methods, both anoxic and aerobic, were used. Moreover a pilot scale SBR fed with municipal wastewater was started to verify the effect of the gradual addition of the concentrated organic wastewaters during the anoxic phase. The SBR was initially fed only with a primary municipal wastewater, then the organic load was increased by adding to the feed, during the anoxic phase, a small amount of the IW1 (second period). Once the initial conditions were restored the load was again raised using the second industrial wastewater (IW2) (third period). With those additions the nitrogen removal efficiency increased from 26% to 50%, in the case of the IW1 and from 23% to 53% in the case of the wastewater IW2, without any negative effect on the global performance of the system. In addition, periodical kinetic studies of denitrification and nitrification in the SBR, were performed.     

Developing methods to evaluate odour control products.

An economical and practical alternative to the standard end-of-pipe odour control methods is the application of liquid odour control products. Currently, there are no established product-testing methods. The data that are available are often of questionable quality and may have limited relevance to waste management. Waste facilities receive differing streams of waste at varying loading volumes. Whilst in operation this exposes control products to a wide variety of environmental conditions, further increasing the difficulty of selecting an effective means of control. The current study initially identifies commercially available odour control products applicable for solid and liquid waste management operations. Bench-scale batch absorption tests have been carried out to investigate odorous gas abatement for a range of selected commercial products and water at a range of pH values. Hydrogen sulphide was the test odorous gas, as it is commonly associated with waste processes. Gas-phase volumetric mass-transfer coefficients (KGa) have been calculated to determine mass-transfer performance. The development of a pilot-scale spray tower is then presented as the testing apparatus for future work. This is an attempt to construct a repeatable testing method for evaluating abatement performance of odour control products, and control the problems encountered when applying odour control products to open sites. KGa values and data collected from tests in this study will be considered in future work as design parameters for the rig.     

Use of agro-food wastewaters for the optimisation of the denitrification process.

The aim of this work was to study the feasibility of the denitrification process enhancement, in the Ciudad Real (Spain) WWTP, by dosing agro-food wastewaters generated nearby the city. The studied agro-food wastewaters were characterised by a high COD and low nutrients concentration. The denitrification rates with these wastewaters were lower than those obtained either with acetate or urban sewage, however the dose of agro-food wastewaters raised significantly the denitrification capacity in the WWTP because of the significant increase of easily biodegradable substrates in the wastewater. From the laboratory NUR batch test it was observed that the best agro-food wastewater to enhance the denitrification process was that coming from tomato processing, which presented an average denitrification rate of 1.9 mg NOx-N/(g VSS.h) and an average denitrification yield of 0.2 mg NOx-N/mg COD. The viability of the use of tomato processing wastewater was checked in a pilot plant optimised for urban sewage treatment with biological nutrient removal. The optimum dose, 5.9 mg COD/mg NOx-N, was applied and 99% of the nitrate was removed from the wastewater without influencing negatively either the COD or P effluent concentrations.     

Use of comprehensive two-dimensional gas chromatography for the broad screening of hazardous contaminants in urban wastewaters.

The list of priority chemicals included in various regulations such as the European Water Framework Directive, as well as the list of hazardous contaminants identified in the aquatic environment, are increasing at an accelerated pace. Therefore, there is a need for broad spectrum methods capable of simultaneously determining hundreds, if not thousands, of contaminants. For the analysis of non-polar or semi-polar contaminants, comprehensive two-dimensional gas chromatography (GC x GC) is more powerful than conventional gas chromatography thanks to a separation on two different stationary phases. This paper reports the use of GC x GC for a broad screening of hazardous contaminants in an urban wastewater plant. Comparison between the raw and treated wastewater has been carried out using a semi-quantitative approach. A variety of drugs, personal care products, pesticides, carcinogens and compounds toxic for reproduction, were identified. Most of these compounds were removed or decreased by this wastewater treatment plant. Preliminary results from this single plant will need to be confirmed by a more extensive study before drawing conclusions on the removal efficiency of 2D-GC amenable compounds.     

Use of satellite data for water resources modelling

Daily data from NOAA¹ satellites are combined with ground‐based meteorological, hydrometric, physiographic and land‐use data in a microcomputer database. A hydrologic model is applied to one basin in the Rocky Mountains and one on the prairies so that the effects of different physiographic and climatic characteristics might be investigated. Results show that using satellite data for areally distributed model inputs such as snow cover is a viable alternative to extrapolating from point measurements.     

Use of 3D modelling and several ultrasound sensors to assess overflow rate.

A new instrumentation mode has been put in place in order to determine the overflow rate of five complex CSOs of the system in Sélestat (French), which are subject to self monitoring. 3D and 1D models have made it possible to predict the shapes of the water lines and suggest a location for the ultrasound sensors. In order to validate the instrumentation principle, three overhead sensors were placed on a weir. The overflow laws suggested are of the type Q(overflow) = a1h1b1 + a2h2b2 + a3h3b3. Early results of the overflow rate that have been obtained by applying the law are close to 10 % of the flow measured in the physical test bench. On the actual site, the ultrasound sensors were assembled on a rail covering the entire weir in order to be able to change their position in future after models calibration.     

Re-use of winery wastewaters for biological nutrient removal.

The aim of this study was to evaluate the feasibility of the re-use of the winery wastewater to enhance the biological nutrient removal (BNR) process. In batch experiments it was observed that the addition of winery wastewater mainly enhanced the nitrogen removal process because of the high denitrification potential (DNP), of about 130 mg N/g COD, of the contained substrates. This value is very similar to that obtained by using pure organic substrates such as acetate. The addition of winery wastewater did not significantly affect either phosphorus or COD removal processes. Based on the experimental results obtained, the optimum dosage to remove each mg of N-NO3 was determined, being a value of 6.7 mg COD/mg N-NO3. Because of the good properties of the winery wastewater to enhance the nitrogen removal, the viability of its continuous addition in an activated sludge pilot-scale plant for BNR was studied. Dosing the winery wastewater to the pilot plant a significant increase in the nitrogen removal was detected, from 58 to 75%. The COD removal was slightly increased, from 89 to 95%, and the phosphorus removal remained constant.     

冷却水运动物理模拟的理论与实践

本文是我国半个多世纪来火,核电厂冷却水运动模型试验研究的一个简要历史回顾。在整体分析水力热力模拟难点和解决途径的基础上,对此领域中常遇见的比较复杂的物理模拟问题所做的一些理论探索、工程模型实践和原体检验作了概括性阐述,包括分别含有风吹、冰冻、波浪、喷气防沙等环境效应的冷却水运动模拟。介绍重点放在实现这种复杂模拟的指导思想和具体措施上,伴以工程实际应用实例说明。     

A case study of regional catchment water quality modelling to identify pollution control requirements.

There are four ecologically important river catchments that contain candidate Special Areas of Conservation (cSACs) under the Habitats Directive in the Lake District National Park located in the North of England. These are the rivers Ehen, Kent, Derwent and Eden. For each cSAC, there are defined ecological criteria that include water quality targets to protect the designated species. Stretches of the riverine cSACs in each catchment are failing to meet these and other water quality targets. The Environment Agency commissioned a study of each catchment to provide the underpinning scientific knowledge to allow it to deliver its statutory obligations under the Habitats Directive. SIMCAT river water quality models were produced and used to predict the water quality impacts resulting from a number of water quality planning scenarios aimed at achieving full compliance with the Habitats Directive and other national and EEC water quality targets. The results indicated that further controls on effluent discharges will allow the majority of targets to be met but other sources of pollution will also need to be controlled. The outcome of the study also recognised that water quality improvements alone will not necessarily produce the required improvement to the ecological interest features in each cSAC.     

N-ViroTech--a novel process for the treatment of nutrient limited wastewaters.

As pulp and paper wastewaters are mostly deficient in nitrogen and phosphorus, historical practice has dictated that they cannot be effectively treated using microbiological processes without the addition of supplementary nutrients, such as urea and phosphoric acid. Supplementation is a difficult step to manage efficiently, requiring extensive post-treatment monitoring and some degree of overdosing to ensure sufficient nutrient availability under all conditions. As a result, treated wastewaters usually contain excess amounts of both nutrients, leading to potential impacts on the receiving waters such as eutrophication. N-ViroTech is a highly effective alternative treatment technology which overcomes this nutrient deficiency/excess paradox. The process relies on communities of nitrogen-fixing bacteria, which are able to directly fix nitrogen from the atmosphere, thus satisfying their cellular nitrogen requirements. The process relies on manipulation of growth conditions within the biological system to maintain a nitrogen-fixing population whilst achieving target wastewater treatment performance. The technology has significant advantages over conventional activated sludge operation, including: Improved environmental performance. Nutrient loadings in the final treated effluent for selected nitrogen and phosphorus species (particularly ammonium and orthophosphate) may be reduced by over 90% compared to conventional systems; Elimination of nitrogen supplementation, and minimisation of phosphorus supplementation, thus achieving significant chemical savings and resulting in between 25% and 35% savings in operational costs for a typical system; Self-regulation of nutrient requirements, as the bacteria only use as much nitrogen as they require, allowing for substantially less operator intervention and monitoring. This paper will summarise critical performance outcomes of the N-ViroTech process utilising results from laboratory-, pilot-scale and recent alpha-adopter, full-scale trials.     

Design of best management practice applications for diffuse phosphorus pollution using interactive GIS

The paper presents a complex environmental engineering tool, which is appropriate to support decision making in watershed management. The PhosFate tool allows planning best management practices (BMPs) in catchments and simulating their possible impacts on immissions. The method has two parts: (a) a simple phosphorus (P) fate model to calculate diffuse P emissions and their surface transport, and (b) an interactive tool to design BMPs in small catchments. The fate model calculates diffuse P emissions via surface pathways. It is a conceptual, distributed parameter and long-term (annual) average model. The model also follows the fate of emitted P from each cell to the catchment outlets and calculates the field and in-stream retention. The fate model performed well in the Zala River catchment as a case study. Finally, an interactive design tool was developed to plan BMPs in the catchments and simulate their possible impacts on diffuse P fluxes. Different management scenarios were worked out and their effects evaluated and compared to each other. The results show that the approach is suitable to test BMP scenarios at small catchment scale.     

Use of an anaerobic sequencing batch reactor for parameter estimation in modelling of anaerobic digestion.

The model structure in anaerobic digestion has been clarified following publication of the IWA Anaerobic Digestion Model No. 1 (ADM1). However, parameter values are not well known, and uncertainty and variability in the parameter values given is almost unknown. Additionally, platforms for identification of parameters, namely continuous-flow laboratory digesters, and batch tests suffer from disadvantages such as long run times, and difficulty in defining initial conditions, respectively. Anaerobic sequencing batch reactors (ASBRs) are sequenced into fill-react-settle-decant phases, and offer promising possibilities for estimation of parameters, as they are by nature, dynamic in behaviour, and allow repeatable behaviour to establish initial conditions, and evaluate parameters. In this study, we estimated parameters describing winery wastewater (most COD as ethanol) degradation using data from sequencing operation, and validated these parameters using unsequenced pulses of ethanol and acetate. The model used was the ADM1, with an extension for ethanol degradation. Parameter confidence spaces were found by non-linear, correlated analysis of the two main Monod parameters; maximum uptake rate (k(m)), and half saturation concentration (K(S)). These parameters could be estimated together using only the measured acetate concentration (20 points per cycle). From interpolating the single cycle acetate data to multiple cycles, we estimate that a practical "optimal" identifiability could be achieved after two cycles for the acetate parameters, and three cycles for the ethanol parameters. The parameters found performed well in the short term, and represented the pulses of acetate and ethanol (within 4 days of the winery-fed cycles) very well. The main discrepancy was poor prediction of pH dynamics, which could be due to an unidentified buffer with an overall influence the same as a weak base (possibly CaCO3). Based on this work, ASBR systems are effective for parameter estimation, especially for comparative wastewater characterisation. The main disadvantages are heavy computational requirements for multiple cycles, and difficulty in establishing the correct biomass concentration in the reactor, though the last is also a disadvantage for continuous fixed film reactors, and especially, batch tests.     

从城市最佳实践区到世博村谈上海世博会给排水设计总控

2010年上海世博会的主题是"城市让生活更美好",城市最佳实践区是最为耀眼的特色之一,世博村是重要的配套工程,有众多的设计单位参与这两项工程,设计总控制定了统一技术标准,起到重要协调作用.介绍设计总控的定位、工作内容,通过列举和对比说明设计总控在这两项工程中的工作重点.从总体管线和单项设计两个方面介绍设计总控在这两项工程的工作情况,列举了如何协调总体管线设计和单项设计衔接、总体给水如何与自来水公司协调、大总体如何与小总体协调、如何制定统一技术标准、统一技术标准如何在单项设计中发挥作用、如何推动单项设计等工作内容.反映不同规模和特点工程设计总控的差别.     

Acidogenic pretreatment of wastewaters containing 2-nitrophenol.

Anaerobic Toxicity Assay (ATA) tests were conducted on acidogenic cultures to assess the feasibility of using acidogenic processes to treat wastewaters containing 2-nitrophenol. Results indicated 2-nitrophenol could be removed with a removal efficiency of more than 98%. 2-aminophenol was identified as the major metabolite of the biotransformation of 2-nitrophenol. Reduction in inhibition potential of acidogenic pretreated effluent was observed in the aerobic process. EC50 values of 2-nitrophenol and 2-aminophenol were found to be 0.065 mM and 1.83 mM respectively.     

Pretreatment and biotreatment of saline industrial wastewaters.

Wastewater from an Akzo Nobel production site contains more than 50 g/l total dissolved salts, mainly chlorides and sulphates, and is currently being treated after 10-20 x dilution. Biological treatment of undiluted or less diluted wastewater is very desirable for environmental and economic reasons. Possibilities were investigated in laboratory scale reactors to treat this highly saline and high strength wastewater aerobically, either after long adaptation or after removing part of the salts by a pretreatment. Adaptation and selection from mixed activated sludge populations took approximately 40 days to finally achieve a COD removal in aerobic treatment of 55-65% at two times dilution (11-16 g/l chloride and 5-7 g/l sulphate). Undiluted wastewater was not treatable. A higher removal percentage (> 80%) was possible at the original high salt concentration only when the sludge load was limited to approximately 0.4-0.5 kg COD/kg sludge/day. A longer adaptation time was required. Nanofiltration (NF) and crystallization could be used as a pretreatment to remove and recover up to 80% of the sulphate in the form of crystallized Glauber salt. Recovery strongly depended on the sulphate and chloride concentration in the NF concentrate and on crystallization temperature. The salt (sulphate) reduction through the NF improved the removal efficiency of a consecutive biotreatment only at a relatively low chloride level, demonstrating that the combination of nanofiltration-crystallization-aerobic biodegradation is less feasible for very saline wastewaters. Anaerobic pretreatment of saline waters turned out to be rather sensitive to high salinities. Only wastewater diluted to 10 g/l chloride could be treated well: sulphate concentration decreased by 80% and COD by 40%. Removal efficiencies of the combined anaerobic-aerobic treatment were approximately 80-85%, proving that this was a feasible route for 2-3 x diluted wastewater. The study has shown that several alternatives are available for treatment of the very saline wastewaters at a much lower degree of dilution than currently practiced.     

BMPs在苏州城市非点源污染控制中的应用

综述最佳管理措施(BMPs)对苏州城市非点源污染的控制,介绍生态集雨沟、植被护坡、草沟和植生过滤带的应用,建议多种BMPs配合使用,充分发挥其在城市非点源污染控制中的优势。     

Use of modelling for optimization and upgrade of a tropical wastewater treatment plant in a developing country.

This paper presents results of a novel application of coupling the Activated Sludge Model No. 3 (ASM3) and the Anaerobic Digestion Model No.1 (ADM1) to assess a tropical wastewater treatment plant in a developing country (Surat, India). In general, the coupled model was very capable of predicting current plant operation. The model proved to be a useful tool in investigating various scenarios for optimising treatment performance under present conditions and examination of upgrade options to meet stricter and upcoming effluent discharge criteria regarding N removal. It appears that use of plant-wide modelling of wastewater treatment plants is a promising approach towards addressing often complex interactions within the plant itself. It can also create an enabling environment for the implementations of the novel side processes for treatment of nutrient-rich, side-streams (reject water) from sludge treatment.     

Nonlinear regression approach to evaluate nutrient delivery coefficient.

Implementation of the Korean Total Maximum Daily Load Act calls for new tools to quantify nutrient losses from diffuse sources at a river basin district scale. In this study, it was elucidated that the nonlinear regression model (NRM) reduces the uncertainty of the boundary conditions of the water quality model. The NRM was proposed to analyse the delivery coefficients of surface waters and retention coefficients of pollutants. Delivery coefficient of pollution load was considered as a function of two variables: the watershed form ratio, S(f), which is a measurable geomorphologic variable and the retention coefficient, phi, which is an empirical constant representing the basin-wide retarding capacity of pollutant wash-off. This model was applied on the Geum River, one of the major basins in South Korea. The QUAL2E was used to simulate stream water quality using NRM. In this paper, we elucidate the possibility to use a nonlinear regression model for delivery and retention of nutrients in a drainage basin characterized as both data-rich and data-poor, and the magnitude of the nutrient loads and sources has been uncertain for a long time.     

Planning, modelling and assessing source control concepts on catchment scale.

Today's water management practice was identified often not to be consistently structured. Usually the decision space is not clearly depicted and then systematically explored. Often stakeholders are involved too late and many objectives are neglected. An adaptive DSS is being developed to help overcoming these problems. Core of the DSS is a "decision matrix", which has been implemented as a web based application (www.wsm300.de). The management objectives are represented by the indicators labelling the rows. They will be the result of a discussion of the objectives and problems in the specific sub-basin, which is supported by the catalogue of indicators. The columns of the matrix are specified by the scenarios whose development is supported by the database of measures and a Geographical Information System (GIS). The matrix, once the labels are defined, serves as a plot for the planning process, defining clearly which objectives have to be considered and which indicator-values have to be calculated. The DSS further includes a concept and tools for the combination of existing software components and supports the processing of model-outputs to indicator-values. Filled with the indicator-values the matrix allows a comparison of the scenarios and provides a good base for a decision. Multi-criteria decision aid methods can (if desired) further help to find the optimal scenario and to mediate between stakeholders. Finding the optimal scenario will likely be an iterative process.