Water Quality Measurement in Industrial Wastewater Treatment
At BOQU Instrument, we embrace the challenge to continuously improve wastewater treatment monitoring equipment and processes to help your industrial plant stay in compliance, and ensure instrument reliability. Best of all, BOQU Instrument solutions will help control costs while operating at the highest possible levels of health and safety. BOQU Instrument has thousands of wastewater treatment solutions for: Beverage,Chemical,Petrochemical,Food,Manufacturing,Maritime,Metals and Mining,Plating,Power Generation,Pulp and Paper,Airports etc
Pre-Treatment of Water Used in Production
During the pre-treatment process, various treatment methods will be utilized, depending on the contamination and the concentration of incoming water from the plant's production side. For instance, pH control can be accomplished by adding a chemical to adjust pH for the other steps in the process. Solids may also be removed as a preliminary treatment process. This may include DAF (Dissolved Air Floatation) to remove solids, fats, oils, and/or greases. Some chemical plants may use a DAF as a way of removing chemical contaminants that separate or float. Chemical addition of coagulant also are used in these processes.We understand your need to measure specific points throughout the wastewater treatment plant. For example, 70% of plants are pre-treatment only and partner with a municipality for the wastewater treatment and 30% have a wastewater treatment plan onsite. Each plant has unique needs, but in general here are the points of measurement you are likely most concerned with: Knowing the pH can help determine the treatment processes required. Certain coagulants may work best at a given pH range so making these adjustments can help improve the process. Identifying the incoming Total Suspended Solids can help determine dosing of those coagulants and air needed to remove the solids. Taking the TSS measurement at the end of the DAF would tell you the efficiency of the process. Total Organic Carbon (TOC) can also be monitored and used for the same type of control depending on the process. Removing as many solids as possible can help maintain the loading and eliminate huge process fluctuations in the biological portion of the plant.
Bulk Tank : The bulk tank is used to hold and equalize the process waste stream. This process helps to gain more stable influent into the wastewater process. Many industrial sites require a bulk tank for firefighting purposes, in the case of a fire emergency. Measurements taken here can give insight as to the treatment processes needed, such as organic loading. Heavier than normal contamination or upset conditions can make for process management issues. Knowing when these are happening can help determine the steps required to maintain control.
Stormwater Tank : Stormwater from a plant can consist of a collection of all water from storms and or potential spills in traffic areas such as loading docks and parking lots. Chemical spills, diesel fuel, gas, oil, and other contaminants need to be monitored and treated before discharged. TOC is becoming very common as a measurement parameter for looking at contaminating levels in these waters. Dissolved oxygen and pH can also give valuable insights into stormwater. During a heavy rain event, larger than usual quantities of water will enter the stormwater tank. This can be good and bad. Dilution of some of the higher contaminated contents helps but it can also make for higher levels of treatment. Separation of high level contaminants can help in the treatment process.
Biological Wastewater Plant
Inlet : During the inlet stage, wastewater is passed through a screen to remove grit and large suspended solids. What is called raw sewage or influent can go through a few different processes depending on what is in the waste stream. Some plants combine process waste with site sanitary sewer. Typically, bar screens are used to remove large contents such as rags, rocks, dirt, and grit from the influent.
Primary Treatment : During primary treatment, primary clarifiers allow organic solids to settle through gravity, while fats, oils, and greases are allowed to float to the surface. The settled solids are referred to as primary sludge and often are thickened in a downstream process before delivery into an anaerobic digester. The floating fat, oil, and grease are collected from the surface and are typically added directly to the anaerobic digester. A typical primary clarifier will remove approximately 70% of the solids and 45% of the Biochemical Oxygen Demand (BOD) from the screened wastewater. Modern facilities that operate enhanced biological nutrient removal processes often extract or ferment the carbon in the primary sludge and dose this side stream into anaerobic or anoxic processes downstream, as a food source for microorganisms. Having a clear understanding of pH and TSS can be of great help in process control at this stage. However, flow rate changes can have a large impact on process control. High organic loading can also impact the process. Knowing as much about your sample can give the operators the ability to react to those changes.
Secondary Treatment : Secondary treatment removes the soluble organic matter, nutrients such as nitrogen and phosphorus, and most of the suspended solids that escape primary treatment. Most often, biological processes are used in which microbes metabolize organic compounds and nutrients to grow and reproduce. The two most common biological secondary treatment processes are attached to growth and suspended growth systems. A suspended growth process fosters the growth of suspended microorganism flocs from individual organisms already present in the wastewater and in the return activated sludge. The flocs contain organisms that can remove the pollutants through aerobic, anoxic, and anaerobic environments. Once the pollutants are removed, the flocs are sent to a secondary clarification process where they separate from the water via gravity. A portion of sludge in the bottom of the secondary clarifier is then directed back upstream to blend with the primary effluent (Return Activated Sludge) to create mixed liquor. The remainder of the sludge is removed from the process (Waste Activated Sludge) to create the ideal ecology of microorganisms. Attached growth systems rely on the microorganisms to attach to a media and create a biofilm. The settled sewage is either mixed or sprinkled over the biofilm-coated media where the microorganisms remove the pollutants. Like the suspended growth process, biofilm fragments and suspended flocs are sent to a secondary clarifier for separation where sludge is recycled and wasted and clean water is discharged to the next process. For biological treatment to function efficiently, microorganisms require nutrients in a balanced ratio, including carbon, nitrogen, and phosphorus (referenced as C:N:P), as well as trace elements including iron, copper, zinc, nickel, manganese, potassium, sulfur, and other components which are typically present in wastewater. The commonly accepted C:N:P Ratio is 100:5:1, although some facilities thrive outside of this ratio, while others experience polysaccharide slime formation or filamentous bacteria growth that inhibit the biology and settling in the secondary clarifier.Multiple biological processes can be employed to complete secondary treatment, including plug flow aeration basins, complete mix aeration tanks, sequencing batch reactors, oxidation ditches, trickling filters, moving bed biological reactors, integrated fixed-film activated sludge, and others. Biological Nutrient Removal (BNR) alters the environment of the microorganisms to remove nitrogen and phosphorus from the water. A BNR process consists of anaerobic (no oxygen or nitrate), anoxic (no oxygen, nitrate is present), and aerobic (oxygen present) stages, during which the water is moved through a series of chambers to perform various biological functions.Chemical treatment processes can also be used, such as the chemical removal of phosphorus. By introducing a chemical precipitant within the aeration basin and clarifiers, phosphorus is removed by flocculation, binding into insoluble compounds that settle out and can be removed as sludge.
Sludge Separation
The method for handling the sludge removed from the process depends on the volume of solids as well as other site-specific conditions. Aerobic digestion is often used by facilities less than eight million gallons per day of inflow. Waste Activated Sludge and if present, Primary Sludge, are added to an aerated reactor where microorganisms feast on the organics and microorganisms present in the sludge to reduce the volatile solids content and the overall mass of sludge. Anaerobic digestion is typically used at facilities greater than eight million gallons per day of inflow, and involves the use of sealed reactors to create an anaerobic environment for different organisms to feast on the organics and microorganisms in the sludge through the processes of acidogenesis and methanogenesis. The methane formed by anaerobic digestion can be used to fuel boilers to heat the digester, flared, or cleaned and repurposed as a green energy source. Removal of the heavy solids helps to reduce the load on the plant, leaving only the dissolved and small organics left to treat. Monitoring the sludge levels in the primary clarifiers can determine the rate of removal. Maintain a healthy sludge level blanket in the clarifier is important for the removal process. Too light a blanket and the process can be upset by the removal arm. Flow rates can be determined by knowing this measurement.
Sludge Management : Thickening involves concentrating the sludge by removing a percentage of the liquid portion by adding polymer compounds and is often employed before anaerobic digestion. Dewatering with belt presses, centrifuges or other means further concentrates sludge into a cake. The cake can be further dried, or simply disposed of through land application or landfills.
Effluent : During the outlet stage, techniques such as filtration, disinfection, and carbon absorption are used to remove the remaining organic load, suspended or dissolved solids, pathogens, and heavy metals that pass through other treatment processes. The goal of this stage is to raise the effluent quality to the level suitable to its intended use, whether for discharge into lakes, rivers, or oceans, reuse as non-crop irrigation (parks, golf courses, greenways, etc), or for groundwater recharge.
Discharge into Receiving Water
A water monitoring station can prepare your plant for safe discharge into receiving waters. While effluent from wastewater treatment facilities is commonly discharged to the environment in rivers, oceans, or other bodies of water, there are a variety of other options for discharge. These include agricultural irrigation; use in parks and recreational facilities (golf courses and sports field irrigation, snow making); wildlife habitat or aquifer/wetland/marsh recharging; industrial uses such as process water; or for street cleaning.
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Industrial Wastewater Parameters
A variety of parameters are used in industrial wastewater pre-treatment, biological wastewater monitoring, and receiving water discharge. Browse the cards below to learn more about why these parameters matter. Or choose Explore Solutions Now to see solutions.
Monitor conversion of ammonia and organic nitrogen forms to nitrite and nitrate during the WW treatment process. Provides information on process conditions in biological treatment stages. At high concentrations and pH, ammonia can be toxic to sludge digestion microbes.
Rcommended model :Model: PFG-3085 Online Ammonia(NH4+) Analyzer,range : 0~5000mg/L
Measuring alkalinity in water will inform its capacity to neutralize acids or absorb hydrogen ions. A slightly alkaline pH is important for effective biological treatment. The process of nitrification destroys alkalinity, which can result in a drop in pH, which will inhibit bacteria. Having visibility into your alkalinity will help avoid permit violations for ammonia and or pH.
Rcommended model :PHG-2081X Online pH/ORP Meter, or PHG-2091 Online pH Meter
Automatic samplers are required to pull samples from different locations within a process so that laboratory tests can be performed. Samples may be collected as a composite or discreetly, depending on site and permit requirements.
Rcommended model :AWS-A803 Online Water Sampler;1000 ml × 25 bottles
BOD5 and BOD indicate a relative measure of “food” available, the degree of stabilization of the wastewater, and estimate the effect of the effluent on the receiving water body. Used for plant loading/design, discharge rate for industrial facilities, and EPA NPDES reporting. Many plants use COD or TOC as an early estimate. Used to calculate % removal.
Rcommended model :BODG-3063 Online BOD Analyzer, CY-5 Laboratory BOD5 Analyzer
Used as a correlative/early indicator of BOD levels. Some NPDES permits include COD as a surrogate for BOD; however, BOD is the standard reportable parameter for oxygen demand in wastewater. COD provides a measure of organic “food” available to biological treatment steps and to estimate the effect of discharge to receiving water.
Rcommended model : CODG-3000 Online COD Analyzer, max range: 15 000mg/L.
Chlorine is added to kill pathogens and reduce odor. Measuring chlorine will help ensure that your wastewater is properly disinfected by removing pathogens as well as satisfy regulations that require the removal of excess chlorine before discharge to surface waters.
Rcommended model : CL-2059A Online Residual Chlorine Meter,0~20mg/L
Color can be an indicator of turbidity or suspended matter. The removal of this matter can be gauged by measuring color, which can indicate if the water quality is suitable for discharge.
Rcommended model : SD-500P Online Color Meter, wide range: 0~500.0PCU
Measuring conductivity is a common method for determining the metal concentration in wastewater. Removal of these metals prevents environmental concerns. Conductivity is also an indicator of dissolved sodium which can assess stages of the treatment process that cause changes in conductivity.
Rcommended model : DDG-2080C Inductive Condcutivity Meter with Torodial Electrodeless Conductivity Sensor, max range:2000ms/cm
To stay alive, the organisms that breakdown organic matter rely on oxygen. When there is not dissolved oxygen present, these organisms will die. On the other hand, too much oxygen could signify that your wastewater treatment process is wasting energy. Measuring dissolved oxygen levels can help dial in the right amount of aeration.
Rcommended model : DOG-2082YS Optical Dissolved Oxygen Meter
Flow measurement is crucial to a plant to know the volume and rate of the liquid passing through each process. These measurements are used to calculate loading and concentration factors for processing.
Rcommended model : BQ-MAG Electromagnetic Flow Meter
Used in conjunction with a water gutter to measure the flow of water in an open channel. It is mainly used to measure the flow rate of sewage discharge ports and urban sewers in sewage plants and enterprise liquid units.
Rcommended model : BQ-OCFM Open Channel Ultrasonic Flow Meter
Nitrate is indicative of the stage of conversion of ammonia and organic nitrogen forms to nitrate by the aerobic biological treatment steps (nitrification).
Rcommended model : PFG-3085 Online Nitrate Ion Meter,max range :5000mg/L
Oxidation Reduction Potential is the ability for a solution to accept or lose electrons, and therefore be “reduced.” ORP can help determine whether activated sludge zones are anaerobic or anoxic to enhance biological nutrient removal. They are best applied as a trending tool.
Rcommended model : ORP-2096 Online ORP Meter
Maintain proper (narrow) pH range for optimal biological processes—especially nitrification. pH and temperature can indicate plant upsets by industrial discharges or the development of anaerobic conditions within the plant. It’s also an important parameter to assess methane formation and avoiding ammonia toxicity in sludge digesters.
Rcommended model : PHG-2091 Online pH / Temperature Meter
Having a clear measurement of sludge helps monitor sludge levels in the aeration tank, where sludge is mixed with air to breakdown organic matter. Monitoring sludge levels can indicate sludge buildup, process and chemical efficiency, and sludge settleability.
Rcommended model : BQ-USM Ultrasonic Sludge Interface Level Meter
Total of ammonia, nitrate, nitrite, and organic nitrogen forms.
Rcommended model : TNG-3020 Online Total Nitrogen Analyzer
TOC levels in water impact treatment and re-use decisions. With data on TOC levels, water managers can make the most efficient and cost-effective decisions for treatment and reuse of important water supplies.
Rcommended model : TOC-5000 Online TOC Analyzer, max range:800mg/L
Phosphorus effluent concentrations are often controlled by discharge permits to limit the addition of nutrients to the receiving body. Total phosphorus may be removed either biologically or chemically. It includes ortho-, poly-, and organic phosphorus.
Rcommended model : TPG-3030 Online Total Phosphorus Analyzer
TSS is the most commonly measured and regulated parameter on NPDES permits. Used to measure mixed liquor suspended solids concentration, return activated sludge/waste activated sludge concentration, influent suspended solids concentration, effluent suspended solids concentration, and % removal.
Rcommended model : TSG-2087S Online TSS Meter,max range:120 000mg/L
COD is the sum parameter that provides the most reliable and timely information about the oxygen-depleting effects of organic pollutants in wastewater. COD also supplies an estimate of the effect of your plant’s effluent on the receiving body.
Rcommended model : CODS-3000-01 Digital Online COD Sensor, range:0~2000mg/L.
Turbidity is a surrogate measurement for solids concentration. This parameter often is used to indicate solids carry-over from secondary clarifiers.
Rcommended model : TBG-2088S Digital Online Turbidity Meter, max range: 4000NTU
