Sedimentation Tank in Water Treatment | Custom Clarifiers & Lamella Systems

A sedimentation tank in water treatment is a clarification unit that separates suspended solids from water by gravity. In simple terms, it gives particles enough time to settle at the bottom while clearer water flows out from the top. It is widely used in municipal water treatment, sewage treatment, industrial wastewater clarification and pretreatment systems.

The basic principle is based on density difference. When water enters the tank, the flow velocity is reduced through inlet baffles or distribution devices. Heavier particles, coagulated flocs or chemical precipitates settle downward under gravity. Clarified water leaves through an overflow weir or outlet channel, while settled sludge is collected at the bottom and discharged for further treatment.

A typical process is:

In water treatment, sedimentation is often used after coagulation and flocculation. Fine particles and colloids may not settle well by themselves, so chemicals such as coagulants or polymers are added to form larger flocs. These flocs settle more easily in the sedimentation tank. In wastewater treatment, the tank may also be used as a primary clarifier before biological treatment, a secondary clarifier after biological treatment, or a chemical settling unit after precipitation.

Common sedimentation tank types include horizontal flow tanks, vertical flow tanks, radial flow clarifiers and inclined plate sedimentation tanks. A lamella clarifier uses inclined plates or tubes to increase the effective settling area inside a compact structure. This is useful when the project has limited installation space or requires higher clarification efficiency.

A complete sedimentation system may include inlet distribution structure, flocculation section, settling chamber, inclined plates, overflow weir, sludge hopper, sludge scraper, sludge discharge pipeline, dosing system, valves, pipelines, access platform and optional control cabinet. For industrial water treatment, material selection is important because the water may contain chemicals, salts, oil, corrosive substances or abrasive solids.

For B2B buyers, selecting a sedimentation tank should not be based only on tank volume. Key parameters include influent flow rate, peak flow, suspended solids concentration, particle settling velocity, surface loading rate, hydraulic retention time, sludge production, chemical dosing requirement, required effluent quality, available installation space and maintenance access. Poor inlet distribution, excessive flow velocity or delayed sludge discharge can reduce clarification efficiency and cause solids carryover.

Sedimentation is effective for settleable solids and formed flocs, but it cannot remove dissolved pollutants, stable emulsified oil or very fine colloids without additional treatment. Depending on the water quality, supporting processes such as coagulation, dissolved air flotation, filtration, biological treatment, membrane treatment or disinfection may be required.

Qingdao Jinwantong provides customized sedimentation tanks, lamella clarifiers and supporting water treatment equipment. Buyers can send flow rate, water quality, suspended solids level, treatment target, site layout and project location for technical selection and quotation.