Equalization Purpose

Industrial and municipal wastewater flows vary hourly and daily. Contaminant concentrations fluctuate with production cycles. Downstream treatment optimizes at steady conditions. Equalization dampens variations delivering consistent flow and loading.

Tank Configuration

Large atmospheric storage basin with multiple inlets from various sources, mixing system preventing stratification, outlet to treatment at controlled rate, level control managing inventory, aeration optional preventing septicity.

Mixing Requirements

Complete mixing essential preventing stratification and dead zones. Mechanical mixers or diffused aeration provide circulation. Proper mixing ensures uniform composition to downstream processes. Mixing intensity prevents solids settling.

Material Construction

Concrete most common for large volumes. Steel tanks with coating for smaller installations. FRP for corrosive wastewaters. Materials resist chemical constituents and biological activity.

Hydraulic Retention Time

Volume provides 4-24 hours storage at average flow. Longer retention dampens greater variations. Typical municipal 8-12 hours, industrial 12-24 hours depending on fluctuation magnitude. Sizing balances equalization versus footprint.

Flow Control

Pumps or weirs discharge at constant rate to treatment regardless of inlet variations. Flow pacing based on average daily flow smoothing peaks and valleys. Level control prevents overflow or emptying.

Aeration Systems

Diffused air prevents anaerobic conditions causing odors and H2S generation. Aeration also provides mixing. Blowers sized for mixing and oxygen transfer. Optional depending on wastewater characteristics and retention time.

Operating Benefits

Stabilizes hydraulic loading preventing treatment upsets. Smooths organic and nutrient loading optimizing biological treatment. Reduces chemical dosing variations in physical-chemical treatment. Improves overall treatment plant performance.

Applications

Industrial wastewater before biological treatment, municipal plants with variable flows, batch discharge operations, pretreatment before membrane systems, and any facility with significant flow or load variations.

Level Management

High level indicates excessive influent requiring diversion or treatment rate increase. Low level signals insufficient flow. Controls coordinate with upstream sources and downstream treatment capacity.

pH and Temperature

Equalization also dampens pH and temperature swings. Mixing blends hot and cold or acidic and alkaline streams. Stabilized conditions optimize treatment chemistry and biological activity.

Solids Handling

Mixing prevents solids settling. Bottom drains or dredging removes accumulated grit and heavy solids. Regular maintenance prevents capacity loss from sediment buildup.

Performance Benefits

Improves treatment efficiency through steady loading. Protects biological systems from shock loads. Reduces chemical consumption through consistent dosing. Smaller downstream equipment sizing for average versus peak flow.

Construction Standards

Concrete tanks per ACI codes. Steel tanks per AWWA standards. Mixing equipment per manufacturer specifications. Proper venting and overflow. Complete documentation with retention time calculations.

ERGIL equalization tanks provide flow and load balancing improving wastewater treatment performance through dampening variations in municipal and industrial facilities.