Water Treatment

INTRODUCTION: Chloride in the form of chloride ion (Cl-) is one of the major inorganic anions in water and waste water and in portable water. The salty taste produced by chloride concentration is variable and dependent on chemical composition of water. The chloride content is higher in waste water than in raw water because of NaCl. Along sea – coast chloride may be presented in higher concentration. It may also be increased by industrial process. High chloride content may harm metallic pipes and structures as well as growing plants. The Argon to metric method is suitable for use in relatively clear water when 0.15 to 10 mg of Cl - is present in portion titrated. The principle behind this method is that in neutral or slightly alkaline solution potassium chromate can indicate the end point or titration of chloride with silver nitrate precipitate sliver chloride quantitatively before red silver chromate is formed. Bromine, iodine and cyanide register as equivale...

INTRODUCTION Biological oxygen demand can be defined as the amount of oxygen (mg/L or mg/kg) used by the non-photosynthetic bacteria at 20 O C to metabolize biologically degradable organic compounds. To obtain stable reading, oxygen consumed is measured over a period of 5 days and it is called BOD 5 . Upon prolonged incubation cells will completely mineralize the organic matter, so it is called ultimate biological oxygen demand. The BOD µ approaches initial COD value. BOD/COD ratio once established can be used to monitor and operate treatment plant. BOD is measured in ppm or mg of O 2 /lit. Decomposition of sewage by microbes results in oxidized end products, which decreases dissolved 0 2 content. Such sewage when mixed in natural water bodies proves harmful. PRINCIPLE: lodometric test is the most precise and reliable titration method for dissolved oxygen analysis. It is based on the addition of divalent manganese solution followed by strong alkali azide. Equivalent amo...

INTRODUCTION: Chemical Oxygen Demand is used as a measure of oxygen equivalent to organic matter content of the sample susceptible to oxidation by strong chemical oxidant. It is useful in monitoring and control of pollution of liquid wastes. The process is carried out at 160 O C in presence of concentrated sulfuric acid. Another parameter used for pollution control is BOD, which also estimates the dissolved oxygen content, but uses biological system. Both the parameters can be correlated. However, COD is used when BOD cannot remove certain wastes like petrochemical waste, volatile alcohol, pyridine and others. PRINCIPLE: Boiling mixture of chromic and sulfuric acids oxidize most types of organic matter. K 2 Cr 2 O 7 reacts with organic matter in presence of heat and the acid oxidizes the organic matter so that the residual K 2 Cr 2 O 7 can be measured. REAGENTS: ·          Standard potassium dichromate solution (0.0147M): Di...

INTRODUCTION Dissolved oxygen levels in natural and wastewater depends on physical chemical and biochemical activities in the water body. Analysis for dissolved oxygen is the key test in water pollution and waste treatment process control. A dissolved oxygen level of 0-8 ppm is normal and supports aquatic life. METHODS FOR ESTIMATION: 1. lodometric method 2. Membrane electrode method 3. Azide modification method 4. Permanganate method 5. Alum flocculation method 6. CuSO 4 sulfuric acid modification method AZIDE MODIFICATION METHOD PRINCIPLE: lodometric test is most precise and reliable titrimetric procedure for dissolved oxygen analysis. It is based on addition of divalent manganese solution followed by addition of strong alkali azides. An equivalent amount of dispersed divalent manganous hydroxide precipitates to hydroxide of higher valency state (Mn +3 ). If no O 2 is present, white precipitates of Mn(OH) 2 are formed. But in the presence of O 2, , di...

PRINCIPLE: A well mixed sample is filtered through a weighed standard glass fiber filter and the residues retained on the filter are dried to a constant at 103 ° C to 105 ° C. The increase in the weight of the filter represents the total suspended solids. If the suspended material clogs the filter and prolonged filtration, the differences between the total solids and total dissolved solids may provided an estimate of the total suspended solids. REQUIREMENTS: ·          Glass fiber filters ·          Filtration device ·          Weighing balance PROCEDURE: ·          Oven dry the glass fiber filter and weigh it. ·          Assemble filtering apparatus and glass fiber filter. ·          Wet filter with a small volume of d...

PRINCIPLE: A well mixed sample is filtered through a standard glass filter and the filtrate is evaporated to dryness in a weighed dish and dried constant weight at 180 O C. The increase in the dish weight represents the total dissolved solids. REQUIREMENT: ·          Evaporating dishes (100 ml capacity) ·          Oven ·          Weighing balance ·          Beakers ·          Measuring cylinders PROCEDURE: ·          Heat clean dish to 103 O C to 105 O C for 1 hour. Store and cool dish in desiccators until needed. Weigh immediately before use. ·          Shake the water sample very well and add 100 ml into filtration device that is having glass filter on it. Apply vacuum and filte...

INTRODUCTION: Solids are referring to matter or dissolved in water or waste water. Solids may affect water and effluent quality adversely in a number of ways. Water with high dissolved solids generally is not potable, and may induce unfavorable physiological reactions in the consumer. For these reasons, a limit of 500mg dissolved solids per liter is desirable for drinking water. Highly mineralized water also is unsuitable for many industrial applications. Water high in suspended solids may not be suitable for bathing. Solids analysis is important in the control of biological and physical wastewater treatment processes. ESTIMATION OF TOTAL SOLIDS (TS) PRINCIPLE: A well-mixed sample is evaporated in a weighed dish and dried to constant weigh in an oven at 105 O C. The increase in weigh over that of the empty dish represents the total solids. REQUIREMENTS: ·          Evaporating dishes (100 ml capacity) ·   ...