Treatment Options for Service Stations

Treatment Options for Service Stations

Treatment process and description	advantages	Typical Risks and Problems
Gravity separation	Remove free O&G Simple design handle larger capacity Minimum mechanical and electrical equipment requirements Low operation and maintenance cost	Large are requirements due to relatively low flow or large tank Limited to removal of free O&G (no removal of oil droplets < 0.02mm or soluble oil)
Air flotation, dissolved air flotation, induced air flotation or mechanical air flotation	Remove both free and emulsified oil. Reduces TSS and COD Remove both floating and settable solids Very small  and light particles can be removed completely in short time	High chemical consumption Relatively high sludge formation
Chemical flocculation with gravity separation or air flotation	Removal of high levels of suspended solids	Chemical sludge produced
Filtration sand, anthracite, multimedia, crushed graphite, oleophilically coated ceramic, hollow fiber membrane cartridge (ultra filtration)	Removal of suspended solids, separation of free, dispersed and emulsified oils	Backwashing, which requires subsequent treatment
Coalescence fibrous membrane	Removes total O&G Small and compact Easy operation and maintanance Low cost	Limited capacity Partial removal of emulsified oil Extensive pre treatment required high potential for fouling not practical for full scale operation
Membrane process reverse osmosis, ultra filtration, hyper filtration	Removal of soluble oil	Membrane fouling and limited life extensive pre treatment low flux rate not practical for full scale operation
Biologicla processes activated sludge	Effective soluble oil removal TSS and BOD reduction	Extensive pretreatment required to reduce the influent oil levels to 40mg/l
Carbon adsorption	Effective removal of all oil components	Expensive Extensive pre treatment required carbon must be regenerated or replace not practical for full scale operation