Disinfection Online Part 2 Recorded

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Instructors: Greg & Patresha Pearson, RN; CSUS-OWP Instructors COPYRIGHT 2011 GREPA Health & Environmental – All rights reserved:

Instructors : Greg & Patresha Pearson, RN; CSUS-OWP Instructors COPYRIGHT 2011 GREPA Health & Environmental – All rights reserved Introduction To Disinfection Dosing & Water Quality Relationships  Part 2

Chlorine Types Continued:

Chlorine Types Continued Calcium Hypochlorite HTH Sodium Hypochlorite Gas Chloramines Chlorine Dioxide Safe Chlorine NSF Certified Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

What You Should Know About Calcium hypochlorite (Ca(OCI)2): :

What You Should Know About Calcium hypochlorite (Ca(OCI)2): Dry granules, powder or tablets High Test Hypochlorite (HTH) 65-70% available chlorine Combustible when combined with petroleum products or other organics Raises pH in water treated Fed with a hypo-chlorinator- through a chemical feed pump Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Characteristics of Chlorine Gas :

Characteristics of Chlorine Gas Greenish/yellow gas – Use SCBA Deadly lung irritant – if inhaled. Very corrosive. 2.5 times heavier than air Seeks lowest point in room due to its weight and specific gravity Expands 450X its volumes when released Compressed liquid on the bottom, with evaporated gas on top Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Chlorine forms in water: :

Chlorine forms in water : Hypochlorous acid- Hydrochloric acids-in small amounts Chlorite Ions (At high pH) Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Hypo-chlorinator :

Hypo-chlorinator Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Calcium hypochlorite system:

Calcium hypochlorite system Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Here’s a Calcium hypochlorite tablet erosion feed system Tablets stacked inside. Water flow erodes and dissolves tablets.

Chlorine Products - Liquid:

Chlorine Products - Liquid Comes in gallon jugs or bulk 5.25 % to 12.5% available chlorine Explosive when combined with HTH Ruins clothing Raises pH of water treated Fed with a positive displacement pump Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Safety Equipment:

Safety Equipment MSDS Use your workplace Right to Know Laws S ome essential safety equipment a water operator should have available when using chlorine gas? SCBA Goggles Gloves, Eye protection equipment □ Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Chlorine Gas:

Chlorine Gas Lowers pH of water Gas leaks detected with ammonia Cylinders could build pressure freeze or rupture keep from fire or excess heat Fusible plug that melts at 158-165 degrees Lead washers used to connect cylinder to regulator can only be used once Very corrosive Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Chlorine Gas – Ton Containers:

Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Chlorine Gas – Ton Containers Lower port can be used to deliver liquid chlorine at up to 900 lb /day. Chlorine evaporator is required.

one Ton gas Cylinders:

one Ton gas Cylinders Contain Pressurized compact CL2 gas at the top Also contain liquid chlorine chemical at the bottom Repaired with a B kit Maximum withdrawal rate 400 to 450 lb /day from gas portion Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Chlorinator Apparatus:

Chlorinator Apparatus Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Venturi creates a vacuum which draws chorine gas. Rotometer reads directly in lbs/day Controls amount of vacuum drawing chlorine out of cylinder Ejector

150 lb Cylinders:

150 lb Cylinders Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

150 lbs Cylinders:

150 lbs Cylinders Maximum withdrawal is 40-42 lbs/day Repaired with an A kit Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Indications of Nitrification :

Indications of Nitrification Sudden increase in a mmonia and nitrate and decrease in O 2 Lower water quality Lower chlorine residual The starting product for nitrogen-containing compounds Ammonia (NH 3 )– Nitrite (NO 2 ) – Nitrate(NO 3) The presence of ammonia at or higher than 0.2mg/l levels is an important indicator of fecal pollution Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Nitrification Prevention/Control:

Nitrification Prevention/Control pH of 7.5-8.5 is ideal condition for Nitrification Early detection is very important Set up a regular monitoring schedule to detect early warning signs i.e : Decrease: Increase: ammonia nitrate (measure levels) chlorine heterotrophic plate count pH- levels bacteria Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Controlling Nitrification:

Controlling Nitrification Clean your reservoir or Tank Establish and maintain regular flushing schedule-is the key decrease your detention time especially during the summer months Increase the chlorine-nitrogen ratio from 3:1 to 5:1 to decrease the amount of uncombined ammonia levels Carefully monitor the chlorine and ammonia feed system-in order not to over dose with chlorine Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Disinfecting A Storage Tank:

Disinfecting A Storage Tank Continuous Method: 50 mg/l for 24 hours Drain tank and refill with fresh water Resample for coliform Limitation: water has to be disposed of and de-chlorinated – this is not practical for large tanks Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Alternative Method :

Alternative Method Spray the inside of the tank with a 200 mg/l sodium hypochlorite solution Let tank sit for about 3 hours Fill the tank Ensure adequate chlorine residual about (3 mg/l) Resample and reinstate your system Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Disinfecting Mains: Continuous :

Disinfecting Mains: Continuous Chlorine is added so that a minimum residual of 50 mg/l is attained in pipe to be disinfected. This solution must circulated through the pipe for 24/h Main is flushed and coliform sampling done before putting back your main into operation Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Disinfecting Pipes : Slug Method:

Disinfecting Pipes : Slug Method Add chlorine solution of 300 -500 mg/l to main. A valve at the opposite end slowly bleeds off water in the pipe so that the ‘slug’ slowly moves through pipeline. The slug of 300 mg/l chlorine must contact each area of the pipe interior for at least 3 hrs. Flush and perform coliform sampling Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

GREPA’s - Pies To Pounds Formula!:

GREPA’s - Pies To Pounds Formula! Put the pieces together to solve Chlorine Dosage Math

dosage calculations Formula!:

dosage calculations Formula! To calculate chlorine dosage in lbs, mg/l, and gallons. Recommendations  : Determine which formula to use  : Memorize & Understand how the formulas work  : Now! Let’s Use the following formulas to solve real problems Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

dosage equations for success:

dosage equations for success In Calculating Chlorine related dosage calculations Here are the 3 success formulas to consider 1 . Gas Chlorine : MGD x mg/l x 8.34 lbs/gal 2 . Bleach : MGD x mg/l x 8.34 (% Strength/100 x s.g. x 8.34) 3 . Solid Chlorine : MGD x mg/l x 8.34 (% Strength/100) Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Slide 26:

T he Davidson Pie Formula Multiply across the bottom To calculate the top MGD x mg/l x 8.34

Solve This Dosage Problem:

Solve This Dosage Problem How many lbs of gas chlorine will be needed per day for a WTP flow at 24 MGD that is to be dosed at 1.5 mg/l? Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Pounds or Pounds per day Flow MGD Dose Mg/l 8.34 lbs Flow = 24 MGD Dose = 1.5 Mg/l Wt of water = 8.34 lbs/gal 24 x 1.5 x 8.34 Lbs/day = 24 MGD x 1.5 mg/l x 8.34 = 300 lbs/day (pure 100% Cl 2 )

Percentage Relationship In Dosing :

Percentage Relationship In Dosing Dividing by the percentage gives the total wt of chemical needed in dosing % is out of 100 1 % =0.01 (decimal) 1/100 1% = 10,000 mg/l 1 % = 10,000 ppm Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Dosage using Calcium Hypochlorite:

Dosage using Calcium Hypochlorite How many lbs of 70% calcium hypochlorite will be needed per day for a WTP flow of 24 MGD that is to be dosed at 1.5 mg/l? Pounds = MGD x mg/l x 8.34 %/100 Flow = 24 MGD Dose = 1.5 mg/l Wt of water = 8.34 % = 70% Pounds = 24 MGD x 1.5 mg/l x 8.34 = 0.7 429 lbs calcium hypochlorite

Dosage using 12.5 % sodium Hypochlorite:

Dosage using 12.5 % sodium Hypochlorite How many gallons of sodium hypochlorite will be needed per day for a WTP flow of 24 MGD that is to be dosed at 1.5 mg/l? the specific gravity is1.2. Gallons Bleach = MGD x mg/l x 8.34 (%/100 x s.g. x 8.34) Dividing by % gives the total wt of chemical needed Dividing by the weight per gallon gives the number of gallons of liquid chemical needed Gallons Bleach = 24 MGD x 1.5 mg/l x 8.34 (12.5 %/100 x 1.2 x 8.34) 240 gallons sodium hypochlorite

Coming Next!:

Coming Next! Review What You’ve Learned! Challenge Your Knowledge With Certification Practice Questions Go Over The Disinfection Worksheet Handout Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

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