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permit requirements from location to location depending on the size of the
receiving facility, whether it serves primarily industrial sources or residential
sources, and its design parameters.
Atypical industrial discharge permit will regulate the following aspects of the
CIP effluent:
1. Corrosive pollutants (acids and bases)
2. Temperature
3. Nutrients (nitrogen, phosphorus)
4. Organic loading or biochemical oxygen demand (BOD; measure ofthe readily
decomposable organic content of awastewater)
Why do these need to be limited before they are sent to atreatment facility? Acids
and bases can cause corrosive damage to the transfer sewer piping as well as the
equipment in the receiving publicly operated treatment works facility (POTW). Both
temperature and pH spikes can inhibit microbial processes at the POTW that are
critical to the treatment of organics. High temperatures can also pose asafety risk if
there are materials with low flash points in the sewer systems. Nutrients and
organic loading sent down the drains from the CIP systems can exceed the design of
the POTW resulting in plant upsets and permit violations for the receiving plant.
This can cause significant issues and penalty fines for the local authority.
Phosphorus, in particular, is often the limiting nutrient for algae and plant
growth. Phosphorus is tightly regulated depending on the receiving body of
water (e.g., Chesapeake Bay, San Francisco Bay, local river, etc.) and the capacity
of the receiving POTW for its treatment.
An example of typical U.S. facility discharge limits relating to CIP discharge is
provided in Table 1(2).Itisexpected that the requirements in Europe and Asia would
be comparable. Some aspects of these permit limits can be negotiated with the local
authorities whereas others are national standards and will not be negotiable.
It is important to recognize from these limits that the design of the CIP
systems and the selection of the CIP chemicals used will impact the design of the
on-site wastewater treatment system and the ability to meet the requirements of an
industrial discharge permit.
WHERE SHOULD THE CIP EFFLUENT BE TREATED?
Most CIP system designers are installing their system in afacility that has or will
have afacility-wide, centralized waste treatment system. Installation of the CIP
TABLE 1 Typical Discharge Limits Compared to CIP Effluent
Permitted aspect Typical limit How does it relate to CIP effluent?
pH 6.5 8.5 pH of untreated CIP solutions range from 2to12
Temperature ( 8 C) 408 C(at POTW headworks), CIP solutions and water rinses are often 808 C
608 Ctothe sewer
or hotter
Total phosphorus Varies by region and
CIP cleaning agents can contain phosphates and
receiving POTW design often phosphoric acid
BOD (mg/L) Varies based on receiving Organic matter rinsed from process equipment
POTW design
(e.g., cell debris and proteins) will affect
BOD loadings
Abbreviations: BOD, biochemical oxygen demand; POTW, publicly operated treatment works.
Rauch and Ankers