1. Sewer survey and stream segregation
Keep desalter, sour-water, spent-caustic, tank-drain and storm-water duties identifiable so concentrated toxic or oily loads do not destabilize the full treatment plant.
Engineering route for oils, phenols, sulfides, ammonia, cod and refinery production variability. Final configuration is based on representative sampling, treatability evidence and the agreed discharge or reuse target.
Reference Capacity and Treatment Boundaries
These reference values are drawn from the supplied petrochemical spent-caustic dossier. They are engineering screening values only; the selected train and acceptance figures are fixed after source segregation, representative analysis and treatability review.
| Refinery design item | Reference value | How it is used |
|---|---|---|
| Combined petrochemical / refinery system | Up to approx. 300 m³/h | Screening capacity; final hydraulic duty includes normal, peak and turnaround flow. |
| Concentrated spent-caustic train | Approx. 1–30.5 t/h | Separate duty for segregated spent caustic, not a general refinery flow claim. |
| Influent COD reference | Approx. 10,000–150,000 mg/L | For high-strength streams; COD fractions and biodegradability determine the route. |
| Sulfide reference | Approx. 500–37,000 mg/L | Sulfide must be analyzed separately from total sulfur before route selection. |
| Oil-removal stage | Free oil below 50 mg/L | Reference separator/equalization outlet before downstream treatment. |
| High-salinity polishing feed | TDS approx. 15,000–20,000 mg/L | Requires scale, corrosion, concentrate and reuse/discharge review. |
Refinery Wastewater Characteristics
Refinery wastewater may combine desalter drains, crude-unit sour water interfaces, tank-farm drainage, oily process water, spent caustic, phenolic streams and intermittent turnaround loads. Each stream is mapped before blending because oil, ammonia, sulfide, phenols, salt and COD do not follow the same treatment route.
Refinery Sources and Treatment Interfaces
Typical interfaces include API/CPI separators, desalter effluent, sour-water stripping, spent-caustic handling, DAF, biological treatment, tertiary polishing, sludge dewatering, vapor/odor control and water-reuse systems. The final battery limits are defined with the refinery process team and site environmental requirements.
Required Refinery Sampling and Design Inputs
Provide stream-by-stream flow, oil and grease, free/emulsified oil split, COD/TOC, phenols, sulfide, ammonia, pH, temperature, conductivity/TDS, suspended solids, metals, cyanide where relevant, chemical inventory, turnaround schedule and current separator/DAF performance. Composite samples and upset samples are both required.
Process Selection Logic
Selection begins with source segregation and treatability tests, then balances biological, physicochemical, membrane and thermal boundaries against residue outlets and acceptance requirements.
Refinery-Specific Treatment Route
2. Oil, solids and vapor control
API/CPI separation, equalization, flotation and covered interfaces recover free oil and manage hydrocarbons, odor and safety boundaries before biological treatment.
3. Sour-water and sulfide control
Spent caustic and sulfide-rich streams are treated as dedicated process duties. Catalytic oxidative desulfurization has a documented reference operating window of approximately 60–95°C and 0.5–0.7 MPaG.
4. Biological and tertiary treatment
Biological treatment is configured only after toxicity, salinity and phenol/ammonia loading are verified; oxidation, carbon, membrane or reuse polishing follows the agreed water-quality target.
5. Residue and concentrate management
Recovered oil, float, sulfur-bearing residue, oily sludge, biological sludge and any membrane concentrate are assigned a defined handling route and compliance responsibility.
Wastewater-Specific Process Flow
- 1. Sewer segregation
- 2. API / CPI separation
- 3. Sour-water interface
- 4. DAF
- 5. Biological treatment
- 6. Advanced polishing
System and Equipment Architecture
Main equipment: API/CPI, equalization, DAF, biological reactors, oxidation, carbon and monitoring systems.
Residues, Utilities and Environmental Interfaces
Recovered oil, scum, oily/biological sludge, VOC and hazardous interfaces are segregated.
Power, air, water, thermal utilities, chemical storage and consumption are calculated from the agreed flow and quality envelope. Off-gas, odor and ventilation controls are incorporated where the selected process requires them.
Automation, Monitoring and Capacity Basis
PLC/SCADA integrates critical instruments, alarms, interlocks, trends and operator controls. Capacity is defined by average, peak and batch flows, equalization strategy, production availability and redundancy requirements.
CAPEX / OPEX Drivers
Major drivers include contaminant load and variability, materials of construction, footprint, redundancy, chemical and energy duties, sludge/concentrate outlet, automation level and the required discharge or reuse quality.
Customer Engineering Inputs and Acceptance
Customer inputs include verified analyses, process inventory, site layout, utility conditions, hazardous-area requirements, local codes and the acceptance sampling protocol. Outputs are agreed as treated water, recovered materials and managed residues at defined battery limits.
Related capabilities: Turnkey process plants, factory modernization, residue recovery, renewable energy and SMART monitoring.
Frequently Asked Questions
What influent data is required for Petrochemical & Refinery Wastewater?
A representative sampling program should cover flow, peaks, pH, temperature, COD/TOC, suspended solids, salts, priority pollutants, toxicity indicators and the intended discharge or reuse target.
How is the process route selected for Petrochemical & Refinery Wastewater?
The route is selected from wastewater characterization, treatability testing, flow variability, site constraints, residue outlets and the agreed acceptance basis.
How should variable or shock loads be managed?
Source segregation, emergency containment, equalization, controlled transfer and online monitoring are defined before downstream treatment.
Which treatment interfaces are important?
Interfaces are selected from pretreatment, biological, physicochemical, membrane and thermal processes according to the wastewater-specific duty.
How are sludge and concentrates managed?
Sludge, flotation scum, spent media, concentrates and recovered materials are characterized, dewatered or contained, and routed to an approved recovery or disposal outlet.
Which utilities and chemicals must be confirmed?
Power, process water, air, steam or thermal energy, chemical storage, ventilation and drainage are calculated from the confirmed design basis rather than assumed values.
What automation and monitoring are normally included?
PLC/SCADA integration and online instruments are selected for critical parameters, alarms, interlocks, trend recording and controlled operation.
How are performance and acceptance defined?
Performance criteria are agreed against the approved influent envelope, capacity, operating conditions, sampling method, analysis standard and discharge or reuse target.