Waste Water and Processing Water Analysis

The quality of process water must be maintained at very high standards, otherwise, there will be uncontrollable contamination of the food being processed at the plant. Waste water emitted from the plant must be handled properly to avoid contaminating the environment. The quality of such water must be determined to facilitate proper handling.

1. Chlorine Content Determination

This work instruction is to ensure process water is assessed for chlorine content in order to determine its suitability for use in production

Equipment and reagents

Housman paleis test DPD tablet number 1 and 3
Comparator disc number 3/40 A & 3/40 B

Work Instructions

Rinse a cell with the sample water
Pour enough sample water to cover the tablet and add one tablet of DPD 1
Shake and allow to disintegrate then make up to 10mls
Mix and match at once and take reading on comparator
This is free residual chlorine
For total residual chlorine add to the cell one DPD 3 tablet and mix and match at once then take reading on comparator disc.
Combined residual chlorine is the difference between free residual chlorine and total residual. Enter the records on water quality book

P.S.: \\

Chlorine added into water reacts first with hydrogen sulphide and the organic matter up to the break-point level, what remains is therefore the amount that will destroy the microorganisms.

Recommended Standards

Free residual chlorine of 0.2 – 0.5 ppm is recommended for potable water.

2. Bacteriological Tests on Waste Water and Processing Water

The purpose of this work instruction is to ensure proper analysis of water.

Reagents and equipment

125ml bottles
25mls universal bottles
Water samples of at least 200mls
Mackonkey broth purple CM5a
Durham tubes (big and small)

Water sampling method

Label each bottle with the laboratory sample number
Mix the sample of water thoroughly by inverting the bottle at least 10 times
Inoculate the bottles of the sterile broth as follows
Add 50ml of water to the bottle containing 50ml (double strength) of MacConkey broth
Add 10ml of water to each of the five Universal bottles containing 10ml of broth (double strength)
Add 1ml of water to each of the five bottles containing 5ml of broth (this is for untreated water samples single strength)
Mix the contents of each bottle
Incubate the inoculated broths in water bath at 44°C for 24 hours with the bottle loosely capped.
After incubation, examine and account tubes that have produced both acid and gas
Read the results from the probability tables.