Testing Method SOP

  Understanding End Point Colour Change in Titration (Water Testing) In titrimetric analysis, the end point is the stage at which an indicator shows a visible colour change, signalling that the chemical reaction is complete. Correct identification of the end point is critical in water and wastewater testing because even a slight error in colour interpretation can lead to inaccurate analytical results. This article explains the concept of end point colour change and highlights common end points observed in routine water analysis. What Is an End Point in Titration? The end point is the point during titration at which the indicator changes colour permanently, indicating that the required amount of titrant has reacted with the analyte. Although the end point is close to the equivalence point, it is identified visually using indicators and therefore depends on proper observation and experience. Correct recognition of the end point ensures: Accurate test results Good repeatability C...

TOC Analysis by Titration: A Simple Guide Total Organic Carbon (TOC) analysis is a critical parameter in environmental monitoring, water quality assessment, pharmaceuticals, and many industrial processes. While modern TOC analyzers often rely on combustion or UV–persulfate oxidation,  TOC analysis by titration  remains an important classical approach—especially for educational labs, method validation, and low-resource settings. This blog breaks down the concept, principle, procedure, advantages, and limitations of TOC analysis by titration in a clear and practical way. What is Total Organic Carbon (TOC)? Total Organic Carbon represents the amount of carbon bound in organic compounds present in a sample. It is commonly used as an indirect indicator of organic pollution in water and wastewater systems. TOC typically includes: Dissolved organic carbon (DOC) Particulate organic carbon (POC) In titration-based methods, TOC is usually determined by oxidizing organic matter ...

  Analysis of Extractable organic ( Oil & Grease) in Hazardous Waste                                                                            Oil and grease are critical parameters routinely analyzed in water, wastewater, and hazardous solid waste . These substances originate from petroleum products, lubricants, fats, oils, waxes, and industrial residues. When present in high concentrations, oil and grease can clog treatment systems, interfere with biological processes, contaminate soil and groundwater, and pose serious environmental risks. This blog explains the principle, materials, and step‑by‑step procedure for estimating extractable organic matter (oil & grease) in hazardous waste using solvent extraction, presented in a clear and plagiarism‑free format. Why Oil & Grease An...

Silica Analysis in Water and Wastewater: APHA Method Silica (SiO₂) is a natural component of water, originating from the weathering of silicate minerals in rocks, soil, and sand. While generally not harmful to human health, high silica concentrations can cause scaling in boilers, fouling of membranes, and operational inefficiencies in water treatment systems. Reliable measurement of silica is essential for industrial water systems, wastewater reuse, and reverse osmosis (RO) processes . The APHA molybdate blue method is a standardized and widely used procedure for silica determination, particularly for reactive silica . Forms of Silica in Water Reactive (Dissolved) Silica Mainly monosilicic acid (H₄SiO₄) Directly measurable by APHA methods Polymeric or Colloidal Silica Forms from condensation of dissolved silica Reacts slowly and may require digestion Particulate Silica Suspended solids (sand, silt, clay) Usually removed before analysis Importance of Silic...

Phosphate Analysis in Water and Wastewater Introduction Phosphates are essential nutrients for plant growth, but when present in excess in water and wastewater, they become a major environmental concern. Elevated phosphate levels are one of the primary causes of eutrophication, leading to algal blooms, oxygen depletion, and degradation of aquatic ecosystems. Because of these impacts, phosphate analysis is a critical component of water quality monitoring and wastewater treatment operations. This blog explores why phosphate analysis matters, common forms of phosphates found in water, analytical methods used for measurement, and their significance in environmental management. What Are Phosphates? Phosphates are chemical compounds containing phosphorus combined with oxygen, commonly found as: Orthophosphates – the simplest and most reactive form Condensed phosphates – polyphosphates and metaphosphates Organic phosphates – phosphorus bound to organic molecules In water and wastewater...

Understanding Acidity in Water: A Practical Lab Guide to Accurate Measurement Water quality sits at the heart of environmental health, public safety, and countless industrial processes. While parameters like pH and turbidity often steal the spotlight, acidity is another critical factor that deserves attention. Elevated acidity can corrode pipelines, disrupt aquatic ecosystems, and compromise drinking water safety. In this post, we’ll walk through a standard laboratory method for measuring acidity in water and wastewater samples . This isn’t just textbook chemistry—it’s a practical, widely used approach that helps protect water resources and ensures regulatory compliance. Why Measuring Acidity Matters Acidity testing determines the concentration of acidic substances present in a water sample. These acids may exist as free hydrogen ions or as compounds that release hydrogen ions when dissolved or hydrolyzed. By neutralizing these acidic components with a standard alkaline solution...

  Biological Oxygen Demand (BOD): A Complete Laboratory Guide Biological Oxygen Demand (BOD) is one of the most widely used parameters for evaluating organic pollution in water and wastewater. It reflects the amount of oxygen required by microorganisms to biologically decompose organic matter under aerobic conditions. This blog presents a  clear, original, and laboratory-oriented explanation of the BOD test procedure , including reagent preparation, dilution techniques, incubation, and calculation Purpose of BOD Analysis The purpose of this procedure is to describe the laboratory method for measuring Biological Oxygen Demand (BOD) in water and wastewater samples. Scope This method is applicable to environmental laboratories involved in the analysis of: Surface water Groundwater Treated and untreated wastewater Industrial effluents where BOD determination is required for monitoring, treatment efficiency, or regulatory compliance. Roles and Responsibilities Lab...

Mastering Iron Detection in Water: The Phenanthroline Colorimetric Method Iron is a common element in water sources and can cause aesthetic and operational issues, including rusty stains and metallic taste. Accurate measurement of iron in water and wastewater is essential for environmental monitoring, industrial processes, and safe water supply. The  Phenanthroline colorimetric method  is a reliable, sensitive, and easy-to-use technique for quantifying iron concentrations. Why Measure Iron? High iron levels in water are more than just cosmetic: Cause orange-brown stains on plumbing, laundry, and utensils Affect taste and color in food and beverages Influence industrial processes and equipment longevity Impact environmental quality for agriculture and ecosystems Monitoring iron ensures compliance with regulatory limits and helps maintain water quality. Principle of the Phenanthroline Method This method measures iron by forming a colored complex: Iron in the sample is conv...

Monitoring Ammonical Nitrogen in Water and Wastewater Monitoring ammonical nitrogen (NH₃‑N) in water and wastewater is essential for evaluating pollution levels, treatment efficiency, and compliance with environmental regulations. Elevated ammonia concentrations can be toxic to aquatic organisms and often indicate contamination from sewage, industrial discharges, or agricultural runoff. This article presents a clear, laboratory‑based Standard Operating Procedure (SOP) for determining ammonical nitrogen using the distillation and titrimetric method , a widely accepted and reliable analytical technique. Why Measure Ammonical Nitrogen? Ammonical nitrogen represents ammonia and ammonium compounds present in water. High levels may: Indicate contamination from domestic or industrial wastewater Cause toxicity to fish and other aquatic life Interfere with drinking water treatment processes Signal incomplete biological treatment in wastewater plants Accurate measurement of ammonical nitr...

Total Hardness Determination (EDTA Titrimetric Method) 1. Purpose This Standard Operating Procedure (SOP) describes a validated method for the determination of Total Hardness in water and wastewater samples using the EDTA titrimetric method. The procedure is designed to produce accurate, precise, and reproducible results suitable for routine laboratory analysis and regulatory monitoring. 2. Scope This method applies to the analysis of drinking water, surface water, groundwater, and wastewater samples in which calcium (Ca²⁺) and magnesium (Mg²⁺) are the primary contributors to hardness. 3. Principle of the Method Total hardness in water is caused mainly by dissolved calcium and magnesium salts. The determination is based on complexometric titration using Ethylenediaminetetraacetic Acid (EDTA) as the titrant. At a controlled pH of 10.0 ± 0.1 , calcium and magnesium ions react with Eriochrome Black T (EBT) indicator to form a wine‑red colored complex. During titration, EDTA prefere...

Chemical Oxygen Demand (COD): A Practical Laboratory Guide Chemical Oxygen Demand (COD) is a key parameter used to assess the level of organic pollution in water and wastewater. It measures the amount of oxygen required to chemically oxidize organic and inorganic matter present in a sample. In this blog, we explain the COD test procedure , its principle, reagents, and calculations in a clear and laboratory-friendly way. Purpose of COD Testing The purpose of this standard operating procedure is to describe the laboratory method for determining Chemical Oxygen Demand in water and wastewater samples. Scope This procedure is applicable to laboratories engaged in the analysis of: Drinking water Surface water Industrial effluents Domestic and municipal wastewater where COD measurement is required for monitoring, compliance, or research purposes. Roles and Responsibilities Laboratory Chemist : Responsible for sample preparation, digestion, titration, and calculation of COD values. Tec...

   Measuring Dissolved  Oxygen in Water and Wastewater: A Laboratory Guide Dissolved Oxygen (DO) is one of the most important indicators of water quality. Whether it’s drinking water, surface water, or wastewater, DO levels tell us a lot about biological activity, pollution load, and overall ecosystem health. In this blog, we’ll walk through the  laboratory procedure for determining Dissolved Oxygen  using the classic iodometric (Winkler) titration method—explained clearly and practically.                                     Purpose of the Test The aim of this procedure is to accurately determine the amount of dissolved oxygen present in water and wastewater samples using a standardized laboratory method. Scope of Application This method is applicable in environmental and water-testing laboratories where routine analysis of: Drinking water Surface water Groundwate...

Measuring Sulfur Dioxide (SO₂) in Ambient Air: A Practical Laboratory Guide. Monitoring  sulfur dioxide (SO₂)  in ambient air is a key component of air‑quality assessment and public health protection. SO₂ is a major atmospheric pollutant generated primarily from fossil‑fuel combustion, power plants, refineries, and other industrial activities. Prolonged exposure can harm human health, damage vegetation, and contribute to acid rain formation. This blog presents a  practical, laboratory‑based guide  to measuring ambient SO₂ using the widely accepted  para‑rosaniline colorimetric method , explaining the principle, reagents, procedures, and calculations in a clear and user‑friendly manner. Why Measure Ambient SO₂? Accurate measurement of sulfur dioxide is essential because: SO₂ irritates the respirat hiory system and aggravates asthma It damages crops, forests, and building materials It contributes to acid rain and secondary particulate formation Regulatory agencies...