Effluent Treatment Plants (ETPs) are crucial in treating the wastewater generated in the industries and particularly in the food processing industries since organic load in these industries is considerable. Chemical Oxygen Demand (COD) is one of the most significant factors to be observed in an ETP. Understanding the width of COD in an ETP system will be very important to enhance the smooth operation of the plant as well as operating under the environmental standards.
What is COD?
COD is a parameter with which the amount of oxygen required for the chemical oxidation of organic and inorganic substances present in water is determined. COD value indicates the extent of organic pollution found in the effluent. High COD means a high organic pollutant level, it implies a high abundance of organic pollutants. It is employed to measure the possible strength of wastewater pollution and assists in construction and control of a treatment process.
Average COD Range in ETP plant for food industry?
As a rule, the values of COD that are present in the influent (incoming) wastewaters of an ETP can be rather much more diversified depending on the character of the industry:
• Domestic sewage: 250 -1000 mg/L
• Textile industry: 1000 -3000 mg/L
• Pharmaceutical industry: 500 -5000 mg/L
• Food processing industry: 2000 - 8000 mg/L and even more
In a food industry ETP plant, the presence of such food ingredients as fats, oils, sugars, stars, and proteins can push COD levels especially high. Raw food processing effluent is not uncommon and a COD concentration of 3000 to 10,000 mg/L is well understood.
ETP OD Reduction
Any ETP has the aim of having lowered COD levels to ensure that the pollution control limits observed by the local authorities have been met. A well and properly designed ETP can contribute to a 80-95% reduction in COD. COD should preferably not exceed 250 mg/L in the treated effluent to be discharged or reused.
The general treatment schemes adopted in ETPs to cut down COD are:
• Primary treatment: screening, sedimentation
• Secondary treatment: Aerobic/ Anaerobic biological s
• Tertiary treatment: Filtration, active carbon, chemical oxidation
Importance for the Food Industry
In an ETP plant for food industry contaminations, it is of extreme importance to control the COD levels. Organic overloads may produce quite anaerobic conditions, resulting in rapid microbial growth and odor problems and overloading the biological treatment facilities. Correct design and monitoring on a regular basis will facilitate consistent efficiency in treatment and compliance with regulations.
The important parameter of effluent quality is OD in any ETP plant. In a trade such as food processing, where the organic load is also maximum, it is necessary to implement a strong ETP plant in the food processing sector as it can manage such high levels of COD. Checking COD does not only put a strain on the environment but also aids sustainable industrial processes.
