Primääripuhdistus

Primääripuhdistus refers to the initial stage of wastewater treatment. Its primary goal is to remove suspended solids and large debris from the incoming wastewater. This process typically involves several physical separation methods.

The first step often involves screening, where large objects like rags, sticks, and grit are removed using screens or grates. This protects downstream equipment from damage and clogging. Following screening, sedimentation is the key process. Wastewater flows into large tanks called primary clarifiers or sedimentation tanks. In these tanks, the flow rate is significantly reduced, allowing heavier suspended solids to settle to the bottom as sludge, and lighter materials like oil and grease to float to the surface and be skimmed off.

The settled sludge, known as primary sludge, is then collected and typically sent for further treatment, such as digestion or dewatering. The clarified effluent, which is wastewater with most of the suspended solids removed, then proceeds to the next stage of wastewater treatment, typically secondary treatment. Primääripuhdistus is a crucial step in reducing the overall organic load and the amount of solids in wastewater before more complex biological or chemical treatment processes are applied. It significantly improves the efficiency and effectiveness of subsequent treatment stages.