Chemical Treatment Plant Research Articles

Effects of thermal disposal of oil-water residues on operation heating plant boiler

Industrial zones are often the source of specifically polluted waters, depending on type of industry. These waters are usually not in the limits for outtake into public sewers and it is necessary to dispose them externally or build-up technologies for their pre-treatment. The article is about the real case of an industrial. A separate sewage network is built for oily water. Solid impurities are separated from the oily water and oily water is treated by evaporation technology. The evaporator produces two types of products - condensate and concentrate. Condensate is a water with high organic content, and it is necessary to purified it by a chemical treatment plant in next step. Evaporator technology remove from water the most of metal content and significantly decrease organic and water content in concentrate. Concentrate is oily stream with lower water content. Water content in concentrate decreased in next technology steps to ca. 40-50 %. The final product is certificated technological fuel, and its final elimination is in the heating plant fluidized bed boiler. The article is detailed focused on the influence of concentrate combustion. A local temperature increases around 10-15 °C extending across the combustion chamber was confirmed. There was also an increase in HF concentration in flue gas. CO concentrations were higher in the first moments of combustion, but the control system responded by increasing the combustion air supply, and CO concentrations were finally lower at the level of 3 mg·m-3. During combustion, there was no provable increase in concentrations of NOX or other substances, and the co-combustion did not have a significant effect on the operation of the boiler, so this way was evaluated like technically and economically effective.

Water and chemical consumption in the textile processing industry of Bangladesh

The textile wet processing industry is considered a notorious polluter due to its widespread use of natural resources without proper replenishment. Bangladesh is one of the largest producers of textile products in the World, and therefore, it is vulnerable to environmental degradation. Bangladesh is predominantly a cotton processing country; therefore, reactive dyes are commonly used, and the dye combination is very water and chemical-intensive. There is a scarcity of information on the consumption of water, textile dyes and the generation of wastewater in the textile sector. Thus, this study aimed to estimate the amount of water use, wastewater generation, and chemical use in textile wet processing units. Therefore, a face-to-face in-depth questionnaire-based survey was conducted in 18 textile wet processing factories, including knit composite, knit dyeing, yarn dyeing, denim dyeing, and knit and yarn dyeing. The average specific groundwater consumption to process 1 Kg of textile materials was 164 L/Kg (SD ~ 81.8); dyehouse water was136 L/Kg (SD ~ 70.6), while corresponding wastewater was 119 L/Kg (SD ~ 73.0). This high consumption of groundwater is directly linked to the depletion of groundwater in the region, where textile industries are situated and also, causes water pollution through wastewater generation. The water used in the dyehouse water was usually soft water and found to be in a range of 68% to 100% that of groundwater extracted. For chemical use, a factory used 449 g of chemicals to process 1 Kg of textile materials, in which the most widely used chemicals were inorganic and basic chemical in nature. However, the chemical use varied from 152 g/Kg to 705 g/Kg of textile production. The total chemical consumption ranged from 954 tons to 4,525 tons a year. More than 50% of the wastewater treatment plants were biological, a quarter of combination and physico-chemical and biological, and the rest were chemical treatment plants in this study. Even though this study may not represent the whole textile wet processing industry of Bangladesh, however, This study provides baseline information on water and chemical consumption and wastewater generation. Our findings would be helpful for policy makers and researchers to identify transformative challenges required at the national level.

Real Time Automation and Ratio Control Using PLC & SCADA in Industry 4.0

Industrial Control Systems (ICS) and SCADA (Supervisory Control and Data Acquisition) systems play a critical role in the management and regulation of critical infrastructure. SCADA systems brings us closer to the real-time application world. All process and equipment control capability is typically provided by a Distributed Control System (DCS) in industries such as power stations, agricultural systems, chemical and water treatment plants. Instead of control through DCS, this paper proposes a SCADA and PLC (Programmable Logic Controller) system to control the ratio control division and the assembly line division inside the chemical plant. A specific design and implementation method for development of SCADA/PLC based real time ratio control and automated assembly line system in a chemical plant is introduced. The assembly line division is further divided into sorting stage, filling stage and the auxiliary stage, which includes the capping unit, labelling unit and then the storage. In the ratio control division, we have defined the levels inside the mixer and ratio of the raw materials through human machine interface (HMI) panel. The ratio of raw materials is kept constant on the basis of flow rates of wild stream and manipulated stream. There is a flexibility in defining new levels and the ratios of the raw materials inside the mixer. But here we taken the predefined levels (low, medium, high) and ratios (3:4, 2:1, 2:5). Control valves are used for regulating the flow of the compositions. In the assembly line division, the containers are sorted on the basis of size and type of material used i.e., big sized metallic containers and small sized non-metallic containers by inductive and capacitive proximity sensors. All the processes are facilitated with laser beam type or reflective type sensors on the conveyor system. Building a highly stable and dependable PLC/SCADA system instead of Distributed Control System is required to achieve automatic management and control of chemical industry processes to reduce waste manpower and physical resources, as well as to improve worker safety.

Analytical Analysis of a Pillar Crane for Handling of Sludge Pumps Breakdown

The article presents a technical description of a boom for handling sludge pumps. It is used in an object No. 900, a block V2 of the nuclear power plant in JaslovskĂŠ Bohunice. It is an object of a chemical water treatment plant belonging to the block V2. The boom is used at regular inspections of sludge pumps type 80 KD F150 9.5-A0-03 and for the needed handling with them during their operation. The boom of sludge pump designed for a load capacity of 120 kg was damaged during operation because the consequence of work the sludge pump was not considered during its design. This was causing a gradual accumulation of sludge around the suction openings of the pump. Therefore, the pump sometimes adhered to the bottom of the tank. In order to lift the pump thus adhered, it was subsequently necessary to apply approximately the four-times greater tensile force, for which the boom was no longer dimensioned. Therefore, it is important to optimize that state.

The influence of a high-density sludge acid mine drainage (AMD) chemical treatment plant on water quality along the Blesbokspruit Wetland, South Africa

The Eastern Basin chemical acid mine drainage (AMD) treatment plant is one of the world’s largest high-density sludge (HDS) plants, and came into operation in August 2016. The plant is situated near the inoperative Grootvlei Mine in Springs, South Africa, and upstream of the Blesbokspruit Wetland, a former Ramsar Wetland of International Importance, now on the Montreux Record. Since being in operation it has had a major influence on surface water quality along the wetland area. The plant was constructed to mitigate the anticipated decant of AMD water from the abandoned Grootvlei Mine into the Blesbokspruit Wetland. Making use of the BACI (Before-After-Control-Impact) design, this study compares surface water quality of the Blesbokspruit upstream (control site) and downstream (impact site) of the treatment plant for 3-year periods before and after it came into operation. Quarterly water quality data (aluminium, ammonia, chloride, conductivity, dissolved oxygen, fluoride, iron, magnesium, manganese, nitrate, pH, phosphate, sodium and sulphate) from 2013–2019 were used for 5 historical Rand Water monitoring sites along the Blesbokspruit. The current HDS treatment process has negatively influenced conductivity, chloride, magnesium, sodium and sulphate levels downstream. Since the commissioning of the treatment plant, the levels of these parameters have increased significantly. Notably, conductivity and sulphate have reached the management range defined as ‘unacceptable’ within the framework set out by the Blesbokspruit Forum (which is less stringent than the national guidelines for aquatic ecosystems), with potential impacts on salinization of the Vaal Barrage downstream. However, the significant reduction of iron, ammonia and phosphate concentrations downstream of the plant may be a combined beneficial effect of dilution by increased discharge from the plant and the wetland removing these contaminants. These results highlight the need for further research into possible secondary treatment and desalinisation mechanisms and the potential ecological and downstream water supply implications of increasing salinity within the area.

Scada system for chemical water treatment plant of the thermoelectric power plant “José Martí”

The monitoring and control of all industrial processes in today's society is an essential requirement to achieve efficient productivity. The main objective of the work is to design a SCADA system for the chemical water treatment plant of the Thermoelectric Power Plant “Jose Marti”. For this, the architecture and the SCADA were designed, the results and contributions obtained from the tests carried out were evaluated. In the work, the PLC M221CE24R was used, which has very good computational performance and an adequate cost/benefit ratio. The design was carried out using the Eros Cuban development platform, version 5.11, and the Modbus TCP/IP protocol was used for communication between the automaton and the Eros. The SCADA that was designed allows to know in real time the parameters and alarms of the plant and the same actions can be executed locally and remotely. For what is viable and necessary, because it guarantees technological independence. The simulation and the tests carried out, both in the laboratory and in situ, validate its functionality and it is designed in a scalable and flexible way to assimilate future extensions.

Modernization of the gas emissions treatment scheme of sodium bisulfite production line from sulfur dioxide

Chemical industry enterprises are the main environmental pollutants that cause environmental problems. This is due to the production technology and the toxicity of some substances. In this paper, it is proposed to purify the gas emissions at the JSC Karpov Chemical Plant formed during the production of sodium bisulfite from sulfur dioxide by the adsorption method. As a sorption material, a modified energy waste - carbonate sludge from the chemical water treatment plant of the Naberezhnye Chelny CHPP - was used. The technological characteristics of the granular sorption material are presented. A batch adsorber with a fixed layer of granular sorption material is calculated. The modernization of the technological scheme for cleaning gas emissions from sulfur dioxide of the production line of sodium bisulfite at JSC Chemical Plant named after L.Ya. Karpov is proposed. The calculation of the prevented environmental damage and the economic effect of the modernization of the technological scheme is made.

Utilization of Oily Sorption Material as a Secondary Energy Resource at Industrial Plants

The article presents research on the possibility of using oily sorption material as a secondary energy resource at industrial enterprises. Carbonate sludge from chemical treatment of thermal power plants is traditionally discharged into sludge collectors, aggravating the environmental situation in areas adjacent to power plants. Based on sludge from chemical water treatment plants of thermal power plants, a sorption material (hydrophobic carbonate sludge) has been developed for the purification of aqueous media from oil pollution. The paper considers the possibility of utilization of the oily material sorbed by the sorption material as a secondary energy resource. The characteristics of the oily sorption material are determined: elemental composition, ash content, net calorific value. A schematic diagram of utilization of oily sorption material is proposed, the volume of air and combustion products during its combustion is calculated, as well as harmful emissions and prevented environmental damage, and thermal calculation was carried out.

Comprehensive Utilization of Low-Potential Geothermal Waters of Southern Russia for Heat and Water Supply and Solution of Environmental Problems

The current state of exploitation of low-potential thermal waters of the East Ciscaucasia Artesian Basin has been evaluated. Low-potential waters, which are the only source of water supply for a considerable number of consumers in the North Caucasus, are being exploited in an extremely inefficient way with at most 20% of the allocated resources being utilized to the fullest extent. Abusive exploitation of the wells resulted in the bogging of large areas around them, depletion of water resources, and deterioration of the latter as a consequence of backflow of low-quality water from adjacent horizons into those being exploited. The quality of the water has drastically deteriorated; in most wells, contaminants, such as arsenic and various organic compounds, have been detected in quantities that considerably exceed the maximum permissible concentrations set for potable water. These thermal waters are not being used for generation of heat and power since their temperature is too low for heat and hot-water supply purpose. However, the resources of low-potential waters are sufficient to solve the problems of heat and hot-water supply and to provide a considerable number of consumers in the region with potable and process water provided that these resources are exploited in a sensible way using new complex technologies. Complex engineering systems comprise a system of heat pump plants in which the low-potential heat of thermal waters is utilized and a chemical treatment plant in which the cooled water is purified from contaminants, thus raising its quality to the potable water standard. The designs and technological parameters of the chemical treatment plants differ depending on the composition and amount of contaminants. The complex systems allow utilization of the product of thermal artesian wells to the fullest possible extent and large-scale introduction of such systems will facilitate the solution of environmental and economic problems in the region and improve sanitary, hygienic, social, and living conditions of people.

Stabilisation of hazardous waste on Langöya

NOAH is established to take care of all hazardous waste not accepted by other companies or exported. The Ministry of Environment owns 52 % of the shares in the company. NOAH is located on two sites; A new fuel blending plant in Brevik for organic waste, and a chemical treatment plant for inorganic hazardous waste on Langöya.

AecomixTM for efficient energy recovery from wastewater and waste streams

Abstract Food and beverage production plants are major wastewater contributors and often have food waste. Particularly plants with wastewaters with a significant total suspended solids and/or fats, oils and greases like in the dairy, redmeat and chicken industry needs to pre-treat their wastewater before high rate anaerobic reactors can be applied. This pre-treatment generally includes undesirable chemical treatment and generates a concentrated side stream which needs to be dealt with. The AecomixTM reactor is an anaerobic reactor with solids retention, particularly suited to treat such effluents, together with available organic wastes. In this manner two waste streams are dealt with in one system and a high level of conversion to biogas is achieved. The solids retention is achieved by Dissolved Biogas Flotation. A full scale AecomixTM reactor treated the effluent of a chocolate/candy factory with a COD concentration varying between 10,000–60,000 mg/l at an average of 37,000 mg/l. The removal for COD and TSS was more than 95% on average. To meet with local discharge regulations a post aerobic biological treatment may be required. The excess sludge from this aerobic system can be returned to the AecomixTM reactor, which is another advantage over high rate (UASB or EGSB type) reactors. The AecomixTM is approximately 50% lower in yearly costs compared to a chemical treatment plant based on flocculation flotation followed by an EGSB reactor.

Experimental studies on the microstructural, physical and chemical characteristics of building derived materials to assess their suitability in ground improvement

Construction and demolition (C&D)1C&D – Construction and Demolition.1 wastes consist of debris generated during the construction and demolition of structural elements. Rapid urbanization renders it necessary to reduce the consumption of non-renewable natural resources drastically and also to limit the dumping of these materials after the expiration of their service life. The primary components of C&D wastes are building derived materials2BDM – Building Derived Materials.2 (BDM) composed of rejected concrete and brick from construction and demolition sites. This study investigates and compares the potential for two different kinds of BDM in their virgin state for the purpose of improving the compaction and shear properties of soft soil having low bearing capacity. BDM are collected separately from demolition of brick walls containing cement-mortar as binder and also from demolition of plain concrete blocks. In the first step, these two types of BDM are compared on the basis of their resistance to impact or crushing loads. Then, the BDM are immersed in separate solutions of seawater, sulfuric, hydrochloric, and nitric acid solutions individually and their responses are determined. Concrete based BDM3CBDM – Concrete based BDM.3 (CBDM) shows greater resistance to impact or crushing, compared to brick based BDM4BBDM – Brick based BDM.4 (BBDM). Moreover, in presence of chemicals, CBDM shows greater resistance to weathering. Hence, for the purpose of ground improvement, CBDM is considered. Soil is partially replaced with different percentages of CBDM and the optimum soil-CBDM combination is found, based on compaction characteristics. This approach intends to prevent the dumping of any kind of BDM as solid waste and also provide an economic option to enhance the properties of soil. In this study, the chemical and physical properties of CBDM, BBDM, and soil are investigated separately. Mineralogical analysis through X-ray diffraction (XRD), and microstructural analyses through scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS) are conducted for CBDM, BBDM, soil, and soil+CBDM mixes. Compaction studies show that the optimum replacement of soil by CBDM is in the range of 17–23% by mass. However, there is a possibility of the presence of aggressive chemicals in soils near the vicinity of water bodies or chemical treatment plants. In order to test the compatibility of the CBDM in such soils, the properties mentioned above are re-evaluated after exposing the CBDM to aggressive chemical environments. Results indicate that virgin CBDM has suitable load carrying capacity, but this capacity decreases after exposure to chemicals. This is associated with change in physical and chemical characteristics of the CBDM, as assessed through XRD, stereomicroscopic imaging, and determination of change in weight. Although the overall performance of CBDM is better than that of BBDM, proper judgement is necessary for their practical application of any kind of BDM for ground improvement depending on location or site conditions.

Decentralized wastewater treatment systems: Efficiency and its estimated impact against onsite natural water pollution status. A Romanian case study

Abstract The paper proposes discussions of some concrete datasets resulted for three solutions of wastewaters management systems applied in case of a Romanian petroleum chemical company. These management options, differing especially in type (centralized or decentralized system) and wastewaters treatment system, were emphasized, mainly by real datasets on treatment performance, polluting species removals, risk of some residuals in treated effluents and natural watercourse nearby, but also environmental impact assessment, using the alternative methodology of global pollution index (I*GP). Interpreting datasets based on in-time analyzed physical-chemical quality indicators and river characteristics, it was estimated the standard quality classification of receiving watercourse as ‘medium’ (water quality indices, WQI = 55.58 − 67.47), affected more or less by treated effluents discharged in it. The environmental risks of some selected residuals in treated effluents and natural aquatic receptor were assessed by the risk quotient (RQ) which appreciated the risk of residuals toward aquatic life as no to low-medium level, with few exceptions. The impact assessment results conclude an admissible pollution status of natural water receptor due to company wastewaters mechanical–chemical–biological treatment plant activities, in decentralized (I*GP = 1.73) and centralized (I*GP = 1.83) system, but generating discomfort effects to aquatic life due to only mechanical–chemical treatment plant operating in decentralized system (I*GP = 2.205). Direct discharge of un-treated industrial wastewaters had been interdicted. These real results underline that decentralized systems are reliable, qualitatively efficient and costly effective, offering long-term solution, and that all wastewaters management strategies of petroleum chemical company had been adapted to specific on-site functioning situations.

Design of Centralized PI Controller for Interacting Conical Tank System

Background/Objectives: The objective of this paper is to design centralised controller for liquid level in the two interacting conical tank system. Methods/Statistical analysis: Two Centralised Proportional and Integral (PI) controller tuning method (Davison method and Tanttu and Liestehto method) are used for simulation and implemented in real time process. Findings: Centralised PI controller reduces the interaction between the two interacting conical tank and improves the system performance. The performances are compared in terms of Integral Square Error (ISE) and Peak Overshoot. It is observed that Tanttu and Liestehto method produces better response than Davison method. Applications/Improvements: Level control in two interacting conical tank is used in chemical industries and water treatment plants.

Dewatering e bonifica dell’ area ˝ex Whitehead Motofides˝ (Pisa, Italia)

In 2007 the activities for the remediation of the “ex-Whitehead Motofides area” (in Marina di Pisa, Italy) started. In order to allow the contaminated soil excavation in dry conditions a dewatering system was necessary. The water pumped through this system was then treated in an adequate plant. Acque Industriali realized and managed the whole system. The dewatering system was made of suction pins fixed to a depth of 5.5 m, connected by a junction manifold to the suction and booster vacuum assisted pump, which allowed the groundwater release toward the plant. The treatment plant, entirely designed by Acque Industriali and called ITAM (Impianto di Trattamento Acque di Falda Mobile, which means movable groundwater treatment), was realized and set up at the end of 2008. It consisted of a pre-treatment section, made of reinforced concrete, prefabricated nitrogen sweep elements, and a physical chemical treatment plant, in a continuous loop, completely made on skid. The plant, with 25 m3/h of maximum potential, was able to remove possible sedimentable or in suspension material particles from water, iron, manganese, residual organic substances such as hydrocarbons, solvents (chlorinated and not), PCBs, and partly heavy metals. Totally, 98,167 m3 of groundwater were managed in about 25 months of activity. The analytic input and output results confirmed extremely high and satisfactory pollutant removal efficiency. The concentration values of the pollutants, in fact, were always lower than the limits imposed by law.

Developments in Back End of the Fuel Cycle of Indian Thermal Reactors

Abstract Substantial progresses made in last five decades in the front end of the nuclear fuel cycle in India has been supported adequately with advances and innovations in the field of back end technology and methodology developments for power reactors in general and thermal reactors in particular. The activities in the back end are characterized by spent fuel transport and storage, reprocessing, waste management and large scale support technology developments. The specifically designed spent fuel transport casks are in operation for shipment of the spent fuel to pre-reprocessing underwater storage facilities operating at Tarapur and Kalpakkam. Three reprocessing plants based on PUREX process located at Trombay, Tarapur and Kalpakkam have been set up to undertake reprocessing of the spent fuel from Trombay based research reactors, power reactors of western sector and southern sector respectively. The complete waste treatment, immobilization and disposal cycle for Low and Intermediate Level waste is in place to manage such waste from power as well as research reactors with a number of chemical treatment plants and near surface disposal facilities operational in various power plant sites. As regards to management of high level liquid wastes mainly arising from the reprocessing stream, two vitrification plants are currently operational whereas third one in under commissioning. One pre-disposal storage facility for vitrified high level waste products is operational at Tarapur while another new storage facility is under construction at Kapakkam. Research and development activities in the field of permanent geological disposal of such vitrified high level waste are in progress. These activities in the back end have been amply supported by development of large technological innovations and design of remote handling systems, robotics, radiation shielding etc. Development of advanced matrices, innovations in processes related to actinide separations and partitioning, recovery of other valuable isotopes are among the areas of future research and developments in fuel cycle of thermal reactors in India.

Complexing agents in waste waters of finnish electrolytic and chemical surface treatment plants

Complexing agents are one of the major environmental concerns in electrolytic and chemical surface treatment (ECST) industry; e.g. the EU reference document on the best available technology (BREF) pays special attention to the usage of EDTA. However, no comprehensive studies are available on usage of EDTA or other complexing agents or their load to the receiving waters from ECST industry. In this study, the concentrations of complexing agents were analyzed to get an overview of their usage and load and also to recognize their relevance in the environmental permitting and compliance monitoring of such facilities. Complexing agent concentrations of treated waste water samples of 23 ECST plants with vat volume exceeding 30 m3 was studied. HPLC and GC-MS were used to analyze and identify complexing agent concentrations, ICP-AES to analyze metals, and TOC to analyse the organic load. The number of the plants in this study equals around 50% of such installations in Finland subject to environmental permit as the IPPC directive provides. EDTA, DTPA, and NTA were found in 11 samples out of 23 mainly in rather small concentrations. Their annual load to the receiving waters may be estimated to be 0.3 tons and the total load from Finnish ECST industry can be extrapolated to be up to 1 ton. Compared to the estimated use of 5-10 tons in the industry this finding is rather low, even though in Finland cast-off treatment baths are typically delivered to the hazardous waste treatment plants. Since the load of complexing agents is rather low, the chemical waste water treatment seems to be either capable of reducing complexing agent concentrations to some extent or their usage is lower than expected. On the other hand, it is possible that not all complexing agents were identified from the samples. The metal concentrations and TOC were well hand in hand with concentrations found in the Finnish environmental database, which proves that the samples were of average quality of the waste water from the facilities. According to the results, complexing agents cannot be considered as an environmental risk in the ECST industry in Finland; EDTA concentrations are clearly below PNECaqua (2.2 mg/l) and the total discharge is very marginal compared to the discharge from the pulp and paper industry. However, DPTA seems to be as commonly used as EDTA, but also biodegradable NTA was found. Since EDTA has gained plenty of attention in the BREF, DTPA and other, poorly biodegradable complexing agents should also be taken into account when the BREF is updated within a few years. Also an EU risk assessment report especially for DTPA should be supplied, since its use is obviously increasing.

Sustainability of wastewater treatment with microalgae in cold climate, evaluated with emergy and socio-ecological principles

The sustainability of a microalgae wastewater treatment plant model (ALGA), assumed serving a small Swedish town with 10,000 inhabitants at latitude 60°N, was tested by comparing it to a conventional three-step treatment plant (WWTP), and a mechanical and chemical treatment plant (TP) complemented with a constructed wetland (TP + CW). Using two assessment methods—the socio-ecological principles method and emergy analysis—the ALGA model considered to have a better position for sustainable development, than the other two. In emergy terms the ALGA model had about half the resource use of the other two alternatives, and used most local free environmental resources, four times the TP + CW, and 100 times the WWTP. The violations against the second and third socio-ecological principles were considered equal for the three alternatives, the fourth was estimated to be in favor of the ALGA model, and the first principle was calculated to be in favor of the ALGA model with about eight times lower indicator value sum. Recirculation of nutrients back to society or production of economically viable products from the treatment by-products would strongly influence the sustainability. The ALGA model has a potential advantage due to interesting biochemical contents in the microalgae biomass, depending on what species will become dominating.

POLISHING CHEMICAL PRIMARY TREATMENT EFFLUENT WITH ONLY A TRICKLING FILTER

POLISHING CHEMICAL PRIMARY TREATMENT EFFLUENT WITH ONLY A TRICKLING FILTERThe North end WWTP in Tacoma, WA, was initially designed as a standard primary plant but was converted to a chemical primary treatment plant using alum and polymer plus fly ash for precipitation of TSS and associated BOD5 in the early 80's. After extensive testing to improve the performance it was converted to just alum and polymer treatment in 1985. In 1992 the City of Tacoma entered into an...Author(s)Orris E. AlbertsonSteve GilbertEric JohnsonH. David StenselSourceProceedings of the Water Environment FederationSubjectSession 22 - Municipal Wastewater Treatment Symposium: Fixed Film Treatment ProcessesDocument typeConference PaperPublisherWater Environment FederationPrint publication date Jan, 2000ISSN1938-6478SICI1938-6478(20000101)2000:12L.64;1-DOI10.2175/193864700784608315Volume / Issue2000 / 12Content sourceWEFTECFirst / last page(s)64 - 88Copyright2000Word count236

Wastewater Neutralization Control Based on Fuzzy Logic: Experimental Results

Many industrial wastes contain acidic or alkaline materials that require neutralization of previous discharge into receiving waters or to chemical and biological treatment plants. The control of the wastewater neutralization process is subjected to several difficulties, such as the highly nonlinear titration curve (with special sensitivity around neutrality), the unknown water composition, the variable buffering capacity of the system, and the changes in input loading. To deal with these problems, this study proposes a fixed fuzzy logic controller (FLC) structure coupled with a tuning factor. The versatility and robustness of this controller has been proved when faced with solutions of variable buffering capacity, with acids that cover a wide pK range and with switches between acids throughout the course of a test. Laboratory experiments and simulation runs using the proposed controller were successful in a wide operational range.