Loading VerChem
Preparing your chemistry tools...
Preparing your chemistry tools...
BOD, COD, and wastewater treatment calculations with Thai effluent standards compliance checking.
Calculate BOD5 from dissolved oxygen readings
Reference values from the Pollution Control Department (PCD)
Industrial Effluent Type A
Strictest standards for industrial facilities
Industrial Effluent Type B
General industrial effluent standards (relaxed)
Community Wastewater
Municipal/community wastewater treatment
BOD5 = (D1 - D2) x DF
DF = Bottle Volume / Sample Volume
BODu = BOD5 / (1 - e^(-k*5))
k = first-order rate constant
COD = (A - B) x N x 8000 / V
A=blank, B=sample, N=normality
>0.5: Easily biodegradable
0.3-0.5: Moderate
<0.3: Difficult
kT = k20 x theta^(T-20)
theta = 1.047 (typical)
E = (Cin - Cout) / Cin x 100%
Cin=influent, Cout=effluent
Check wastewater against Thai effluent standards instantly
Ensure proper treatment before discharge
BOD5, COD, k-rate, loading, efficiency, and more
Standard Methods for Water and Wastewater analysis
Get calculations in milliseconds with step-by-step solutions
Clear pass/fail indicators with exceedance details
BOD measures the amount of oxygen consumed by microorganisms to decompose organic matter in water over 5 days at 20C. Higher BOD indicates more organic pollution. BOD5 is the standard 5-day test used worldwide.
COD measures the total quantity of oxygen required to oxidize all organic material in water using a strong chemical oxidant (dichromate). COD is always higher than BOD because it includes non-biodegradable organics.
The BOD/COD ratio indicates how biodegradable the wastewater is. Ratio >0.5 means easily biodegradable (suitable for biological treatment). Ratio <0.3 means difficult to biodegrade (may need chemical/physical treatment first).
Thai effluent standards are set by the Pollution Control Department (PCD). Type A is strictest (industrial estates), Type B is general industry, and Type C is for community/municipal wastewater. All discharges must comply with these limits.
The k-rate (deoxygenation rate constant) describes how fast organic matter is decomposed. Typical values range from 0.1-0.3/day. Higher k means faster decomposition. It varies with temperature, waste type, and microbial activity.
VerChem offers a complete suite of chemistry calculators and tools