Water Treatment

BOD/COD Treatment

Chemical and bio-augmentation products for the reduction of biological oxygen demand (BOD) and chemical oxygen demand (COD) in industrial wastewater, supporting biological treatment, chemical oxidation, and effluent polishing to meet discharge compliance.

Wastewater Treatment Biological Treatment Chemical Oxidation Effluent Compliance

Chemical Approaches

H₂O₂ · Fenton · Coagulation

Biological Support

Nutrient Dosing · Bio-augmentation · pH Control

Key Parameters

BOD₅ · COD · TOC · BOD:COD Ratio

Discharge Standard

PROPER / AMDAL (PerMenLHK No.68/2016)

Overview

BOD (Biological Oxygen Demand) and COD (Chemical Oxygen Demand) are the two primary measures of organic contamination in wastewater. BOD measures the oxygen consumed by microorganisms as they biologically degrade organic matter over five days; COD measures the oxygen equivalent of all chemically oxidisable organic and inorganic species. Both parameters are regulated in Indonesian industrial discharge standards under PROPER and AMDAL frameworks.

High BOD/COD in discharged wastewater depletes dissolved oxygen in receiving water bodies, causing ecological harm to aquatic life. For industrial facilities including refineries, petrochemical plants, LNG terminals, food processing plants, palm oil mills, meeting BOD/COD discharge limits is a critical compliance obligation and a signal of overall effluent treatment plant performance.

BOD and COD reduction relies primarily on biological treatment, including activated sludge, biofilm reactors (MBBR), trickling filters, anaerobic digestion, supported by chemical processes for pre-treatment, optimisation, and polishing. The chemical products supplied by Lamurindo target the supporting chemistry: optimising biological treatment conditions, providing chemical pre-treatment to remove non-biodegradable COD fractions, and enabling advanced oxidation for refractory organics that biological systems cannot fully remove.

BOD:COD ratio as a biodegradability indicator: A BOD:COD ratio above 0.4–0.5 indicates readily biodegradable wastewater suited to conventional aerobic biological treatment. Ratios below 0.3 indicate significant non-biodegradable (refractory) COD, common in refinery and petrochemical effluent containing aromatic hydrocarbons, surfactants, and polymer additives. Refractory COD cannot be removed by biological treatment alone and requires chemical pre-treatment or advanced oxidation before or after the biological stage.

Treatment Approaches

Supporting Biological Treatment

Nutrient Dosing (N & P)

Aerobic biological treatment requires nutrients, primarily nitrogen and phosphorus, in a specific ratio relative to BOD (typically BOD:N:P = 100:5:1). Industrial effluents that are high in carbon but nutrient-limited, common in refinery and chemical plant wastewater, will have sluggish biological performance until nitrogen (urea, ammonium sulfate) and phosphorus (di-ammonium phosphate, phosphoric acid) are dosed to achieve the target nutrient balance.

pH Correction for Biological Treatment

Activated sludge organisms are highly sensitive to pH; optimum range is 6.5–8.5. Acidic or alkaline industrial effluent streams will shock the biological system and cause sludge bulking, loss of nitrification, or biomass washout. Caustic soda or sulfuric acid dosing upstream of the bioreactor stabilises pH and protects biological performance during fluctuating process drains.

Bio-augmentation (Microbial Seeding)

Concentrated preparations of specialised microorganisms such as hydrocarbon degraders, phenol degraders, biosurfactant producers that accelerate the acclimatisation and recovery of biological treatment systems handling industrial organic loads. Applied during ETP startup, after toxic shock events, or to boost degradation of specific compounds (phenols, BTEX) that native sludge handles poorly.

Chemical Oxidation for Refractory COD

Hydrogen Peroxide (H₂O₂)

A clean oxidant that decomposes to water and oxygen. Used for direct oxidation of dissolved organics, for odour control (H₂S oxidation), and as the oxidant source in Fenton and catalytic advanced oxidation processes. Does not introduce problematic by-products. Effective for oxidation of phenols, BTEX, and other moderately refractory organics at elevated dose and temperature.

Fenton Reagent (H₂O₂ + FeSO₄)

Reaction of H₂O₂ with ferrous iron generates highly reactive hydroxyl radicals (•OH), a non-selective oxidant that attacks and breaks down a wide range of refractory organic molecules. Effective for industrial wastewater containing phenols, dyes, surfactants, and petroleum hydrocarbons that resist biological or simple H₂O₂ treatment. Requires acid pH (2.5–4.0) for maximum radical generation; treated water must be re-neutralised afterwards.

Coagulant-aided COD Removal

Coagulants, particularly ferric salts, can physically precipitate and remove a fraction of the colloidal and high-molecular-weight organic COD. Not oxidative, but reduces total organic load entering biological treatment, making the biological system more stable and productive. Applied as a pre-treatment ahead of biological systems handling high-SS, high-colloid industrial wastewater.

Applications

Application	COD Challenge	Treatment Approach
Refinery ETP, biodegradable fraction	Oil, grease, BTEX, naphthalene (BOD:COD ~0.4–0.6)	Pre-treatment (API separator + DAF) → activated sludge; nutrient dosing; pH control; bio-augmentation with hydrocarbon degraders
Refinery ETP, refractory fraction	Phenols, PAHs, surfactants (non-biodegradable)	Fenton pre-treatment or GAC adsorption to reduce refractory COD before biological stage; or tertiary AOP after biological treatment
Petrochemical plant ETP	Process chemicals, catalysts, solvents; variable BOD:COD ratio	Segregated treatment of concentrated streams (equalisation + Fenton); dilute mixed streams to biological; nutrient + pH control
LNG condensate treatment	BTEX, dissolved aromatic hydrocarbons from gas condensate	Stripping (air/steam) for volatiles; biological treatment + bio-augmentation; GAC polishing for residual dissolved organics
Palm oil mill effluent (POME)	Very high BOD (~25,000 mg/L); biodegradable fats and proteins	Anaerobic pre-treatment (biogas capture) → aerobic polishing; nutrient dosing; coagulant for TSS reduction in final effluent
Food & beverage effluent	High BOD from sugars, fats, proteins	Aerobic biological treatment (ASP or SBR); nutrient balance; coagulant for TSS polishing before discharge

Petrochemical & LNG Applications

Refineries and petrochemical complexes are among the most challenging environments for BOD/COD management. Their wastewater contains a complex mixture of biodegradable and refractory organics, high suspended solids, variable pH, inhibitory compounds (phenols, heavy metals), and large diurnal load fluctuations. Managing these streams requires a comprehensive chemical programme.

In refinery effluent treatment plants, the biological activated sludge system is the core treatment technology but it requires careful chemical support. Nutrient (N and P) dosing is typically needed as refinery wastewater is strongly carbon-loaded but nutrient-limited. pH must be controlled to protect the sludge biology from acidic drains (from sour water strippers) and alkaline drains (from caustic wash systems). The refractory COD fraction, phenols, polynuclear aromatics, surfactants, may require Fenton pre-treatment or GAC polishing to achieve PROPER Biru or Hijau COD discharge limits.

In LNG terminal operations, the primary organic contamination challenge comes from gas condensate handling, particularly during condensate loading operations where the handling and transfer of LNG condensate generates contaminated stormwater and wash water containing BTEX compounds. These aromatic compounds are partially biodegradable but require a well-maintained, properly conditioned biological treatment system with adequate hydraulic retention time. Bio-augmentation with BTEX-adapted microorganism cultures can significantly accelerate startup of biological treatment systems at new LNG terminals and after periods of low organic loading that cause biomass die-off.