Sequencing Batch Reactor for the Removal of Nickel from Refinery Wastewater

A petroleum refinery is a complex combination of interdependent industrial
processes that generate wastewater effluent containing oil, ammonia, sulfides,
chlorides, mercaptans, phenols and other hydrocarbons. The most important
pollutants are organics, oils, suspended solids and other toxic materials referred to as
priority pollutants. 80% of which may be considered hazardous because of the
presence of toxic organics and heavy metals. Accidental discharges of large
quantities of pollutants can occur as a result of abnormal operation in a refinery and
potentially pose a major local environmental hazard. Previous studies have shown
the reasonable performance of biological systems in refinery wastewater treatment.
Therefore, in this study a Sequencing Batch Reactor (SBR) was studied for treatment
of wastewater from equalization tank of PETRONAS Refinery Plant (PPMSB) at
Melaka. A 4-litres SBR was fed with real wastewater and seeded with the sludge
from same plant. A 12-hour cycle (15,585,60,15 and 45 minute for fill, reaction,
settle, draw and idle phases, respectively) was conducted in the SBR for treating 4
litres of wastewater per cycle. Initially the wastewater was characterized and then the
influent, effluent and sludge samples were analysed for COD, MLSS, MLVSS and
SVI. Next and after acclimatization period, nickel was added to the system in
concentrations of 0.1 and 0.2 mg/l to study the efficiency of SBR in treating
wastewater contains nickel. Results show the wastewater characteristics of refinery
wastewater according to measured parameters which are COD, Nickel, Phosphorus,
Nitrate, Turbidity and pH which contains of 322 mg/l, ,
2.3 mg/I, 1.80 mg/l, 1.0 mg/l,
79.9 NTU and 6.72 respectively. After going SBR treatment, the result of measured
parameters of COD, Nickel, Phosphorus, Nitrate, Turbidity and pH are 29.70 mg/l,
0.017 mg/l, 3.10 mg/l, 15.70 mg/l, 16.80 NTU and 6.95 respectively. The COD and
Nickel removal efficiency were achieved approximately 70-90% and 78-80% correspondingly.