Full-scale Pilot Plant Research Articles

Ammonium Removal in Wastewater Treatments by Adsorbent Geopolymer Material with Granite Wastes: Full-Scale Validation

Elevated ammonium (NH4+) concentrations in untreated waterways contribute to eutrophication and dissolved oxygen depletion. Geopolymer (GP) materials are introduced as sustainable, straightforward operation and low-cost option for pollutant adsorption through ion exchange mechanism. In the present study, a porous metakaolin-based geopolymer with granite waste additions was synthetized, characterised and validated as adsorbent material for NH4+ pollution in water. At this point, treatments to reduce GP alkalis leaching were also considered to comply with the water discharge regulations. The adsorption mechanism was analysed by Redlich-Peterson isotherm model concluding that NH4+ was disposed on the GP surface as a monolayer with strong physical-chemical attraction between molecules. Kinetics of the process followed the Weber-Morris rate equation being the intraparticle diffusion the limiting process. Continuous experiments at lab-scale suggested a maximum removal of 97% during the first hours and an adsorption capacity (q) of 25.24 mg/g. Additionally, as a main novelty of the work, the GP was validated in a full-scale pilot plant monitoring pH, electrical conductivity and NH4+ concentration. The obtained data revealed that the GP is high selective in a real wastewater stream and removed 81% of NH4+, higher adsorption values than those reported for natural and some synthetic zeolites.

Occurrence, identification and removal of microplastics in a wastewater treatment plant compared to an advanced MBR technology: Full-scale pilot plant

Microplastics are of increasing interest as one of the most important threats to the natural environment and aquatic life. One of the main pathways of microplastics entering the aquatic and terrestrial environment are wastewater treatment plants. The aim of this study was to investigate the occurrence and removal of MPs in both wastewater and sludge from an MBR-based and a WWTP. The focus is on the amount of microplastics emitted into the environment, the efficiency of removal in wastewater treatment plants and how their operation and design, could be improved to reduce the presence of these pollutants in the effluent. The results showed that the influent (SI) had mean concentration of 507 ± 70 MPs L-1, in the reactor tank (SRS) the concentration increases to 1.77 × 107 ± 1.61 × 107 MPs kg-1 (dw) and in the permeate (SP) the estimated amount of microplastics decreased to 1.58 ± 1.08 MPs L-1. This is a removal efficiency of 99.69%, with respect to the estimated average MPs. After the clarifier (SC) and sand filtration (SSF) a mean of 17.38 ± 4.71 MPs L-1 and 2.93 ± 1.50 MPs L-1 respectively were found, resulting in an efficiency of 96.58% and 99.42%, respectively, regarding the inlet water of the treatment plant. The two predominant forms in all samples (except for SCS) were fragments and fibers. In total 25 types of polymers were detected, and only 5 resulted in all types of samples, the most detected polymer families were Acrylates and Polyethylenes.

Removal of emerging contaminants from wastewater using nanofiltration for its subsequent reuse: Full–scale pilot plant

Effluents from wastewater treatment plants (WWTPs) are widely recognized as the main source of emerging contaminants (including stimulants and antibiotics) in natural water courses. The problem is aggravated in those regions where water is scarce and its reuse is necessary. With the aim of avoiding these problems, the present paper reports the results obtained by installing a nanofiltration membrane at the outlet of the secondary decanter at the WWTP situated in the municipality of Medina Sidonia (SW Spain). Permeate samples were taken over a period of 72 h while the membranes were operating. Contaminants belonging to the aforementioned families (caffeine, theobromine, theophylline, amoxicillin and penicillin G) were analysed by means of liquid chromatography with mass spectrometry (UPLC-MS). The results indicate that nanofiltration removed these contaminants from the wastewater turning the treated water as suitable to be reused for all the uses included in the Spanish Royal Decree 1620/2007 on water regeneration and reuse.

Pilot size matters: the case of a full scale pilot for P-recovery from digestate in Belgium

In Leuven, Belgium, a full-scale pilot plant to test P-recovery from digested municipal wastewater sludge was built in April 2013. This paper illustrates the value of using large-size pilot-plant by explaining the economic evaluation of the installation. The uncertainty analysis of the price per tonne of phosphorus (P) recovered on the basis of the information available during planning is compared with analyses after six months and then two years of operation. It is shown that the most sensitive of the economic model's parameters should determine the size of the pilot-plant.

Simultaneous carbon and nitrogen removal from municipal wastewater in full-scale unaerated/aerated submerged filters

Characterization and evaluation of a biological submerged filter was carried out on a full-scale pilot plant performing removal of biochemical oxygen demand (BOD) and total nitrogen (TN) from pre-treated urban wastewater. The average influent values of BOD5, chemical oxygen demand (COD) and TN were 370, 1,015 and 60 mg/L, respectively. The pilot plant produced good discharge quality during steady-state operation. Average effluent BOD5, COD and TN values were 11, 58 and 15 mg/L, respectively. The reactor had been operating beyond its organic design capacity (200 population equivalent (PE)). At 480 PE the removal achieved for BOD, COD and TN were 98, 97 and 78%, respectively. This technology can absorb pollutant overloads while maintaining stable performance. Denitrification was performed by using sewage itself as carbon source. It was used as an intermittent aeration cycle in the unaerated cell to improve the denitrification process. The predenitrification with submerged unaerated filter has proved to be an efficient process for advanced removal of TN.

Multiobjective Optimization of a Fixed Bed Maleic Anhydride Reactor Using an Improved Biomimetic Adaptation of NSGA-II

A fixed bed maleic anhydride reactor is simulated using an improved reactor model. A simplified Langmuir–Hinshelwood-type reaction kinetics is used, and the kinetic as well as the reactor parameters (for a full-scale pilot plant reactor and an industrial reactor) are tuned. The model is then used to solve a few optimization problems involving a single and multiple objectives from among maximum productivity, minimum operating cost, and minimum pollution. This is carried out using NSGA-II-aJG. A semiempirical procedure is suggested to reduce the scatter in the Pareto optimal solutions obtained for the three-objective optimization problems, and replace solutions which are associated with extreme sensitivity (this is different from obtaining a robust Pareto set, where all the optimal points have reduced sensitivity). Thus, our focus is twofold: modeling and multiobjective optimization of MA reactors, and improving the algorithm to deal with the extreme sensitivity of the three-objective problem (which may be ...

The role of SSVF and SSHF beds in concentrated wastewater treatment, design recommendation

The return flows of reject water from sewage sludge dewatering alter the activated sludge process in a conventional WWTP and increase TN concentration in the final effluent from WWTP. The objective of the investigation carried out was to consider the application of multistage treatment wetland (MTW) for the treatment of reject water from sewage sludge dewatering in a centrifuge (RWC). This paper aims to present the design and performance of each stage of the treatment as well as the efficiency of total MTW. The full scale pilot plant for RWC, consisting of two vertical flow beds (SS VF) working in series, followed by an horizontal flow bed (SS HF), was built in 2008. The applied configuration ensured a very high removal efficiency of principal pollutant (COD - 76.0% and NH4+-N - 93.6%). In the investigated facilities, the SS VF beds ensured an effective removal of nitrogen compounds, especially NH4+-N, whereas the decomposition of hardly degradable Org-N and COD took place in SS HF. This research illustrates that the MTW could be successfully applied for the treatment of RWC.

Prevention of Refinery Tower Plugging by Residual Oil Gellant Chemicals in Crude-Pilot Plant Evaluation of Alternative Oil Gellants

Abstract Earlier work by the authors(1) described refinery plugging caused by volatile phosphorus components originating from phosphate ester oil gellants. Also documented were two successful field trials of new phosphonate ester oil gellants which were shown to address this problem. In a later work(2) the authors presented the results of additional field testing of phosphonate ester gellants directed at the optimization of cost and performance. In addition to the phosphonate ester systems previously tested, new modified phosphate ester systems will also become commercial. These modified phosphate esters also reduce volatile phosphorus according to ASTM D-86 distillation testing. However, several questions required further investigation. One of these is the comparative ability of phosphonate and modified phosphate esters to control volatile phosphorus and tower fouling at higher temperatures in the presence of steam. Distillations used to evaluate volatile phosphorus to date have had a 250 ºC endpoint and did not include water. Another continuing area of concern has been organic halide formation under distillation tower conditions. Although no organic halides were detected in either of the two initial field trials reported earlier (1), further testing under more realistic conditions was required. To address these questions in the most meaningful way possible, full-scale pilot plant testing was conducted over several days with flowback captured after actual fracturing treatments. Fouling of a tray inserted in the pilot plant distillation tower was measured as well as fouling of the packing material. In addition, any changes in operating parameters such as rate, temperature or pressure over the time of each test were noted, as these could also be indicative of fouling. This paper presents the conclusions of this testing and should serve as a guide to the selection of oil gellant systems for the reduction of refinery tower and heat exchanger fouling. Introduction The D-86 distillation procedure used to evaluate volatile phosphorus to date has a 250 ºC endpoint. The actual bottom temperature in the towers is approximately 340 ºC. Also, fluids typically have a 2- to 4-minute residence time in the tower bottom. However, the pot temperature in the D-86 distillation is not specified as part of the procedure and may exceed 340 ºC in some instances, even given that the endpoint measured in the distillate is 250 ºC. Based on observed smoking of the oil samples in some distillations, the oil in the distillation flask may be cracking. Because of this, results may be inaccurate and difficult to reproduce. In addition, esters may decompose at elevated temperatures through a hydrolysis mechanism if water is present. Steam is injected into the bottom of the towers, serving as a source of water. However, the D-86 test methodology does not include the addition of an aqueous phase. Another continuing area of concern has been organic halide formation under distillation tower conditions. Although no organic halides were detected in the flowback of the two initial field trials reported(1), further testing under more realistic conditions is required.

Prevention of Refinery Tower Plugging by Residual Oil Gellant Chemicals in Crude: Pilot Plant Evaluation of Alternative Oil Gellants

Abstract An earlier paper(1) described refinery plugging caused by volatile phosphorus components originating from phosphate ester oil gellants. Also documented were two successful field trials of new phosphonate ester oil gellants that were shown to address this problem. A second associated paper(2) presented results of additional field testing of phosphonate ester gellants directed at the optimization of cost and performance. In addition to the phosphonate ester systems previously tested, a new modified phosphate ester system has become available. The modified phosphate ester also reduces volatile phosphorus according to ASTM D86 distillation testing. However, several questions require further investigation. One of these is the comparative ability of phosphonate and modified phosphate esters to control volatile phosphorus and related tower fouling under more representative conditions. The D86 distillation procedure used to evaluate volatile phosphorus To date has a 250 °C endpoint. The actual bottom temperature in the towers is approximately 340 °C. Also, fluids typically have 2 to 4 minutes residence time in the tower bottom. However, the pot temperature in the D86 distillation is not specified as part of the procedure and may exceed 340 °C in some instances, even given that the endpoint measured in the distillate is 250 °C. Based on observed smoking of the oil samples in some distillations, the oil in the distillation flask may be cracking. Consequently, results may be inaccurate and difficult to reproduce. In addition, esters may decompose at elevated temperatures through a hydrolysis mechanism if water is present. Steam is injected into the bottom of the towers, serving as a source of water. However, the D86 test methodology does not include the addition of an aqueous phase. Another continuing area of concern has been organic halide formation under distillation tower conditions. Although no organic halides were detected in the flowback of the two initial field trials reported in an earlier paper(1), further testing under more realistic conditions is required. It has been hypothesized that on the larger scale of an actual distillation tower, water hydrolysis may occur. This could result in localized areas of acidity and causticity. In the presence of acid at elevated temperatures, halogenation reactions could occur if halogen ions, such as chloride ions, are present. Any carryover of salts not removed in the de-salters, could serve as this source of halide ions. To address these questions in the most meaningful way possible, full-scale pilot plant testing was conducted over several days with flowback captured after actual fracturing treatments (see Figure 1). Fouling of distillation tower trays were measured, as well as fouling of the packing material. In addition, any changes in the operating parameters such as rate, temperature or pressure during each test were noted because these could also be indicative of fouling. Three full-scale pilot evaluations were conducted using actual flowback fluids from fracturing treatments conducted with three different oil gellants:Convention phosphate ester currently in use. The purpose of this test is to serve as a blank for comparison and for validation of test methods. We expect tower fouling with this product. If no fouling occurs, the test method is invalid.

Wastewater treatment with activated pre-clarifier and planted soil filters

With a series of buffer tank, activated pre-clarifier (SBR) and planted soil filters, it is possible to get a stable degradation and good effluent values in the case of unsteady inflow and changing concentrations. In the process presented here the activated pre-clarifier is working as a denitrification tank and the soil filter as a nitrification reactor. An automatic control manages the storm-water runoff, the water-recirculation returns the nitrate and provides a minimal feed. Experiences with this plant from 1999 to 2005 are given in this paper, research has been done in the project "Planted soil filters as a Biotechnological Process", founded by the German Federal Environment Foundation (DBU). A full scale pilot plant was built to treat wastewater from composting sides, with a 42 m3 SBR and a bed area of 2 x 550 m2 of the planted soil filters. Now, after six years of operation, the results are still satisfactory. Besides this pilot plant, landfill leakage and municipal wastewater have been treated in a technical scale plant with the same process in an 80 L SBR and 0.75 m2 vertical flow soil filter with good results.

Minimisation of excess sludge production in a WWTP by coupling thermal hydrolysis and rapid anaerobic digestion

In many cases, reducing sludge production could be the solution for wastewater treatment plants (WWTP) that here difficulty evacuating the residuals of wastewater treatment. The aim of this study was to test the possibility of minimising the excess sludge production by coupling a thermal hydrolysis stage and an anaerobic digestion with a very short HRT. The tests were carried out on a 2,500 p.e. pilot plant installed on a recycling loop between the clarifier and the actived sludge basin. The line equipped with the full scale pilot plant produced 38% TSS less than the control line during a 10 week period. Moreover, the rapid anaerobic digestion removed, on average, more than 50% of the total COD load with a hydraulic retention time (HRT) of 3 days. Lastly, the dryness of the remaining excess sludge, sanitised by the thermal hydrolysis, was more than 35% with an industrial centrifuge. This combination of thermal hydrolysis and rapid anaerobic digestion equally permits a significant gain of compactness compared to traditional anaerobic digesters.

Deposition of Ti1−xAlxN using bipolar pulsed dual magnetron sputtering

Bipolar Pulsed Dual Magnetron Sputtering (BPDMS) technique has opened a wide range of opportunities for the deposition of insulating layers. In BPDMS, two magnetrons alternately act as a cathode and an anode and hence preserve stable operation over long process times. Owing to the versatility and the numerous variables in a BPDMS process, also deposition of conducting coatings such as Ti1−xAlxN is of great interest.In the present work, Ti1−xAlxN coatings have been deposited in a full-scale pilot plant using BPDMS. Two DMS pairs each comprised of one Ti and one Al target have been used for the deposition. The influence of sputtering pulse times on the Ti and Al magnetrons, respectively, and the nitrogen partial pressure on the process characteristics as well as coating properties have been investigated.Threefold substrate rotation has been used during the deposition and the deposition rate was about 1 μm/h. The use of single-metal targets of Ti and Al and threefold substrate rotation resulted in nanolayered coatings and it has been shown that the characteristics of the coating can be varied within a wide range. For example, the Al-content in Ti1−xAlxN has been varied as 0.16<x<0.84 by varying the sputtering pulse times and the N2 pressure. The coatings change from columnar [200]-textured to less columnar [111]-textured with increasing Al content. For the highest Al contents (x>0.58) the deposited coatings are XRD amorphous with a glassy morphology. Also the coating hardness and elastic modulus are sensitive to the variation of the metal ratio as demonstrated in the paper.

Experimental and full–scale pilot plant constructed wetlands for municipal wastewaters treatment

The Hierarchical Mosaic of Aquatic Ecosystems (HMAE ®) was originally developed in Belgium by applying the ecological adaptations of hydrophyte plants to flooded and polluted conditions. The system consisted of a stabilization pond (stage I) followed by a semi-aquatic ecosystem planted with helophytes (stage II) and by a terrestrial ecosystem (stage III) where ligneous species are planted. An HMAE ® experimental system net treatment area of 9.4 m 2 per one equivalent inhabitant (e.i.) showed a high average performance for SS (66.5%); COD (89%); BOD 5 (87.5%) and fecal bacteria (99.997%). The decrease of the treatment area of 2.8 m 2/e.i. showed a average high performance for SS (75%); COD (80%); BOD 5 (82%) and fecal bacteria (99.9%). An HMAE ® system was built in Bustillo de Cea (Leon, northwest of Spain) and their removal efficiency was studied. Organic matter, nutrients and fecal bacteria were fortnightly analyzed. The whole system showed removal efficiencies in start-up as high as 98% for solids, 95% for BOD 5 and up to 99.99% for fecal bacteria.

Modelling of Pulp Flow Rate with Variable Consistency

Pulp and paper mills can be seen as big pumping plants, where mass is pumped from one step to another. The proper operation of the process in its different stages does not allow large deviations from given operation conditions, which makes it essential to monitor and control the flow rate and the consistency of the pulp. A structure is suggested for the modelling of pulp flow rate, and possibilities for using the pump-valve system as a flow meter are examined. The overall model structure consists of a Wiener model for pressure difference, a non-linear dynamic valve model, and a static mapping for flow rate. A full-scale pilot plant of pulp flow through a valve in a pipeline is used for experimentation. Linear dynamics and non-linearities due to the pump, valve and the pulp consistency are identified based on online measurements obtained from calibration tests. The results show that a simple model could be identified which, together with a valve model, can be further applied for the purposes of accurate flow control.

Tertiary treatment in a vertical flow reed bed system – a full scale pilot plant for 200–600 P.E.

In Strengberg, Lower Austria, a vertical flow reed bed system (gravel/sand) was chosen as a new type of tertiary treatment which was designed as a full scale pilot plant with various possibilities of operational use. The surface of the vertical flow pilot plant amounts to about 600 m2 and is divided into four beds whereby two different depths of substrate are used. The application of the conventional plant effluent is carried out in intermittent flushes and at changeable time intervals. Final nitrification and partial denitrification and elimination of phosphorus are the main goals to be achieved. In the framework of the present research project the load limits will be determined by gradually raising the influent load. The efficiency and operational reliability within the whole year period (summer/winter) are considered to be an important factor for establishing general dimensioning approaches. The pilot plant has been in operation for more than one year now. Different operational stages up to a hydraulic load of 1.3 m2.p.e.−1 (i.e. 0.75 m2.p.e.−1) were carried out. The average chemical oxygen demand (COD) of the reed bed effluents varied from 1 to 20 mg.1−1. Not surprisingly the ammonium (NH4-N) results showed more variation. Results, thus far, indicate NH4-N removal efficiencies between 40% and 90%.

Natural Sludge Dewatering. I: Combination of Freezing, Thawing, and Drying as Dewatering Methods

A Swedish full-scale pilot plant employing all-year-round natural sewage sludge dewatering is presented in this paper. The treatment includes three different types of outdoor ditches: a freezing ditch for the winter months, a drying ditch for the early summer months, and a combined drying-freezing-thawing-drying (DFTD) ditch for sludge produced in late summer and early autumn. The test period included two consecutive winters. Complete freezing of the sludge was achieved in the first winter in contrast to the second when incomplete freezing of the sludge occurred due to an unusually warm winter. The dry matter content for the freezing ditch was, at the harvest in August, 30–70 of the first test year. The second test year yielded a sludge with a dry matter content of 20–40 in the freezing ditch. The final dry matter result for the DFTD ditch was 20–40. The summers included were similar to the extent that both late summers were unusually warm, helping to produce sludge of high final dry matter content. The f...

Tertiary treatment in a vertical flow reed bed system - a full scale pilot plant for 200–600 p.e.

In Strengberg, Lower Austria, a vertical flow reed bed system (gravel/sand) was chosen as a new type of tertiary treatment which was designed as a full scale pilot plant with various possibilities of operational use.The surface of the vertical flow pilot plant amounts to about 600 m2 and is divided into four beds whereby two different depths of substrate are used. The application of the conventional plant effluent is carried out in intermittent flushes and at changeable time intervals. Final nitrification and partial denitrification and elimination of phosphorus are the main goals to be achieved. In the framework of the present research project the load limits will be determined by gradually raising the influent load. The efficiency and operational reliability within the whole year period (summer/winter) are considered to be an important factor for establishing general dimensioning approaches. The pilot plant has been in operation for more than one year now. Different operational stages up to a hydraulic load of 1.3 m2.p.e.−1(i.e. 0.75 m2.p.e.−1) were carried out. The average chemical oxygen demand (COD) of the reed bed effluents varied from I to 20 mg.l−1. Not surprisingly the ammonium (NH4-N) results showed more variation. Results, thus far, indicate NH4-N removal efficiencies between 40% and 90%.

A full-scale test of a biological nutrients removal system using the sequencing batch reactor activated sludge process

A full-scale pilot plant using SBR process was experimented with an actual wastewater emanating from a recreational center. The main purpose of this investigation was to evaluate applicability in the field and process removal efficiencies in terms of BOD, SS, TN and TP and its corresponding kinetic parameters. It was found that removal efficiencies were comparable with results of other studies reported in the literature. BOD removal was observed to be 95% on average while SS removal to be 89% on average. Removal rate of nitrogen was 70% in terms of total nitrogen and that of phosphorus was 77% in terms of total phosphorus. Effluent concentrations were 7.3mg/ Q BOD, 10Amg/ Q SS, 13.6mg/ Q TN and 0.9mg/ Q TP. Effluent quality was maintained consistently stable by controlling decantation quantity and operating cycles. Denitftication/nitrification were accomplished during anaerobic/aerobic processes and the conversion rates were 4.5mg/kgMLSS/hrand 1.5mg/kgMLSSrhr, respectively. The sludge yield coefficient was 0.32 whereas sludge phosphorus luxury uptake was as high as 5.6wt% at the end of aerobic cycle. Microscopic examination revealed that microcytes that were observed predominantly in sludge were Vorticella, Epistilis, Aspidisca (protozoa) and Philodina (rotatoria). This experiment may prove that SBR process is one of the most promising technologies that can be employed to treat organic matter as well as nutrients in wastewaters that are generated from such sources as recreational facilities because of fluctuations of wastewaters in terms of quality and quantity.

A full-scale test of a biological nutrients removal system using the sequencing batch reactor activated sludge process

A full-scale pilot plant using SBR process was experimented with an actual wastewater emanating from a recreational center. The main purpose of this investigation was to evaluate applicability in the field and process removal efficiencies in terms of BOD, SS, TN and TP and its corresponding kinetic parameters. It was found that removal efficiencies were comparable with results of other studies reported in the literature. BOD removal was observed to be 95% on average while SS removal to be 89% on average. Removal rate of nitrogen was 70% in terms of total nitrogen and that of phosphorus was 77% in terms of total phosphorus. Effluent concentrations were 7.3 mg/??? BOD, 10.4mg/??? SS, 13.6mg/??? TN and 0.9mg/??? TP. Effluent quality was maintained consistently stable by controlling decantation quantity and operating cycles. Denitrification/nitrification were accomplished during anaerobic/aerobic processes and the conversion rates were 4.5mg/kgMLSS/hr and 1.5mg/kgMLSS/hr, respectively. The sludge yield coefficient was 0.32 whereas sludge phosphorus luxury uptake was as high as 5.6wt% at the end of aerobic cycle. Microscopic examination revealed that microcytes that were observed predominantly in sludge were Vorticella, Epistilis, Aspidisca (protozoa) and Philodina (rotatoria). This experiment may prove that SBR process is one of the most promising technologies that can be employed to treat organic matter as well as nutrients in wastewaters that are generated from such sources as recreational facilities because of fluctuations of wastewaters in terms of quality and quantity.

Question of the Month

This month's question concerns arsenic removal from Park City, Utah's source water. The article gives a brief overview of how the Park City system tested and selected the right process for their needs, and provides a brief explanation of how it works. A brief overview of the oxidation process is given, along with a description of the full scale pilot plant testing.