Richard, yes, there is precedent. The process of "break point" chlorination
depends on adding enough chlorine to react with all organic matter (break
point) and leave have a residual (excess) level of chlorine (0.5 ppm?) to
protect the water during distribution. It should always have some residual
chlorine. If the water does not have residual chlorine then it never reached
the "break point". If there is a problem with getting enough chlorine in the
water then maybe the water source is not clean enough. You must have enough
dwell (contact) time between chlorination and measuring chlorine level to
accurately judge if you have reached the break point. In watersheds with
high organic load, water often has much more than 0.5 ppm free chlorine
because the necessary contact time is very long and the "break point" has
not been reached.
I don't know all the details but they are available. These rules apply in
the US to all Municipal water systems and would apply to all sources of
water used in food manufacturing.
Ken Hilderbrand
-----Original Message-----
From: owner-seafood@ucdavis.edu [mailto:owner-seafood@ucdavis.edu]On
Behalf Of Richard Chivers
Sent: Monday, January 21, 2002 3:07 AM
To: seafood
Subject: Chlorination of water in the tropics
I have a client in Africa who is chlorinating his incoming water supply
until residual chlorine is present, then storing in covered tanks at ambient
temperatures (25-30(C) until the water is required for washing raw fish and
glazing the end product.
His inspectors insist that they require free chlorine at all times. Do you
know of any precedent for this, as the bug counts show the water to be
effectively microbiologically safe, and the tanks are kept clean and
securely covered.
Richard Chivers
Fisheries Consultant
Seafood Audit International
21 Mitchell Street
Wellington
Somerset
UK
TA21 8LF
+44 (0) 1823 666666
www.fishonline.co.uk
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