Oil industry liquid waste is waste that comes from the results of the process of processing
petroleum. The petroleum industry produces liquid waste that can have a negative impact
on the environment because petroleum processing produces several substances that fall
into the category of dangerous and toxic goods (B3). Among the organic chemicals
contained in the liquid waste of the petroleum industry is ammonia or NH3. Ammonia
content is very limited in liquid waste, where according to PERMEN LH No. 19 of 2010
the maximum quality standard for ammonia in liquid waste is 8 mg/L. This research was
conducted to determine the effect of giving coconut shell activated carbon which can
adsorb ammonia with size and mass variables using the adsorption method. The object of
this research is a sample of the Outlet Water of the Wastewater Treatment Plant (IPAL) of
PT. Pertamina RU IV Cilacap with an initial ammonia value of 183.65 mg/L. This research
was conducted by providing variations in the size of activated carbon, namely 50 mesh;
75mesh; 100mesh; 125mesh; and 150 mesh. While the mass variation of activated carbon
is 0.5 grams; 1.0 grams; 1.5 grams; 2.0 grams; 2.5 grams in every 50 ml sample. The
results showed that the size variation of activated carbon was able to provide the best
reduction in 100 mesh with a percentage reduction of 85.0%. while the mass variation of
activated carbon gave the best reduction in ammonia at 2.0 grams in 50 ml samples with a
percentage reduction of 88.4%. The results of the reduction of ammonia given to both
variations of the study had a fairly high percentage but were not able to reduce to the
threshold of the ammonia quality standard.