Saturday, 4 February 2012

Ethylene Glycol in Industrial Wastewater Treatment

Ethylene Glycol in Industrial Wastewater Treatment

Hello all environmental associates!
We are back in your e-mail box. This time around we’d like to share some uncommon experience and information with regard to effluent treatment. Treating effluent containing Ethylene Glycol.
Recently, I received an inquiry from a client friend who attended a public seminar on Wastewater Treatment Systems – operation, maintenance and troubleshooting, where I was the I.P.A’s main presentor. A few weeks later he inquired me through the e-mail and asked me if Ethylene Glycol has any effect to BOD, COD and SS of treated effluent. So I decided to begin working on the waste stream and source for origins of this substance in wastewater. I contacted various resource network and associates and began to seek more input on this matter. Here’s what I gathered. Please read through – surprise!

What is Ethylene Glycol?
It is organic diol-lipid, colorless, viscous, sweet taste but has no smell. It can cause dramatic toxicity where the Lethal Dose for adult human is 100ml and considered to be absolutely soluble as it’s Specific Gravity is 1.1 at 20 0C.  Melting point is –130C while Boiling Point is 197.60C. It has a vapour density of 2.14 and Vapour Pressure of 0.06mm Hg at 200C. The simplest form of its family is 1,2 – ethanediol with structural formula HOCH2 – CH2OH.
Toxicity: It is itself relatively non-toxic, but, after absorption (e.g. skin) the unchanged compound undergoes glomerular filtration and passive re-absorption. It is then broken down into metabolites that are highly toxic and causes the associated findings of ethylene glycol toxicity.
Who uses Ethylene Glycol and for what purpose?
If we have a ‘normal’ vehicle that uses the conventional Hydraulic Brake System, then we are the most abundant user! Ethylene Glycol is commonly found in brake oil as it serves as blending stabilizer agent in brake fluids and helps prevent solidification in sub-zero temperatures.

In addition to this, almost all our cars and most performance bikes are fitted with the Radiator Engine Cooling System. (I remember how Randy Mamola had tilted his bike rear-end up just to flush out his radiator coolant at the end of every GP as the cap jammed! .. just kidding!). In the temperate countries, anti-freeze agents are commonly used in Car Radiators as coolants and many other fluid applications. They contain Ethylene Glycol.

Significance in Environmental Management

For the automotive service industry that provides service-bay workshops – the generation of Spent Brake Oil, Spent Coolant or Spent Radiator Water mixed with Spent Coolant is a common and relatively continuous activity. Thus, they are significant environmental aspects that require careful remediation as its associated impact can spread throughout the entire component of the local biosphere or transported to adjacent associated natural cycles – with a definite eruption to the normal biochemical life patterns. In an industrial setting it is used as a solvent or as the raw material for a variety of processes. Please check our MSDS or CSDS to justify this.

Impact to human

Ethylene Glycol is rapidly absorbed once it is ingested and it then widely distributed into body tissues. Peal blood levels are generally seen in 1-4 hours. Exposure to the skin and lungs may cause irritation but does not cause the systemic toxicity in the way that Methanol does. Lethal quantities in adults are considered to be 100 ml.
Upon inhalation:            Vapour inhalation is generally not unless heated or misted. Exposure to vapours over an extended time period has caused throat irritation and headache. May cause nausea, vomiting, dizziness and drowsiness. Pulmonary edema and central nervous system depression may also develop. When heated or misted, has produced rapid, involuntary eye movement and coma.

Upon ingestion:        Initial symptoms in massive dosage are similar to alcohol intoxication, progressing to CNS depression, vomiting, headache, rapid respiratory and heart rate, lowered blood pressure, stupor, collapse, and unconsciousness with convulsions. Death from respiratory arrest or cardiovascular collapse may follow. Lethal dose in humans: 100 ml (3-4 ounces)
Upon skin contact: Minor skin irritation and penetration may occur.
Upon eye contact:    Splashes may cause irritation, pain and eye damage
Chronic exposure:    Repeated small exposures by any route can cause severe kidney problems. Brain damage may also occur. Skin allergy can develop. May damage the developing fetus.

 Wastewater Treatment Plant

In Malaysia, as point-source wastewater segregation in many industries seems like ‘Something for the near future, still’, it is common to find heterogeneous mixtures of raw influent entering the wastewater treatment plant. By virtue of the nature of this organic substance, it has to be treated differently from many other organic wastes. Good news is that wastewater contaminated with this substance is not so difficult to treat. One source claims that mechanical aeration is necessary for ethylene glycol remediation, plus using a type of biological seeding with their brand name. In other words, for anyone who doubt the treatability of ethylene glycol in industrial effluent before this, should now have fresh lead.

Impact to the environment

According to an MSDS of this substance form Mallinckrodt Chemicals of the U.S that manufacturers this substance, which says… “ When released into the soil, this material is expected to readily biodegrade… and leach into groundwater, and not expected to evaporate significantly. When released into the water, this material is expected to have a half-life between 1 and 10 days. This material is not expected to significantly bioaccumulate. When released into water, this material is not expected to evaporate significantly. When released into the air, this material is expected to be readily degraded by reaction with photochemically produced hydroxyl radicals, and is expected to have a half-life between 1 and 10 days. Environmental Toxicity: The LC50/96 – hour values for fish are over 100 ml/g.”

Therefore, please engage appropriate control measures to prevent this environmental aspect from being translated into any form of impact.
How the ISO14001's 'Input-Output' Analysis is helpful in identifying Environmental Aspects which are Hazardous Wastes?
The electroplating process generates an array of Scheduled Wastes.
Identification of environmental aspects which are Scheduled Waste
requires such comprehensive approach. Legal obligation and liability.
It is for this very reason that one should not simplify this method further. I worry about perhaps some potential misinterpretation by those who don't have enough time to think what they read, of what is written in Guidance Clause A.6.1.2, paragraph 5 of the ISO14001:2015 which states .. " An organization does not have to consider each product, component or raw material individually to determine and evaluate their environmental aspects; it may group or categorize activities, products and services when they have common characteristics." If a general categorization of organizational activities is being used then most care should be in place as materials like Ethylene Glycol may only be recorded as 'wastes' or 'chemical wastes'. Regrouping some manufacturing activities or processes scheme into one category say 'Production' is indeed a good summary but may lead to the omission or 'overlooking' of important environmental aspects. Hence, this task must be justified by experienced personnel. 

I hope the above is substantial for us to understand the potential harm of Ethylene Glycol to any environmental media and mankind. Written and published for affiliates and friends in 2007 by Khalid Mohd Ariff