Kloakk

Kloakk is the term used for wastewater and the network and facilities that collect, convey, and treat it. It includes domestic, commercial, and industrial effluent, and in many systems also stormwater. The goal of kloakk infrastructure is to protect public health and the environment by preventing pollution of watercourses and the atmosphere.

A kloakk system typically consists of an underground network of pipes, pumping stations, and, in some places, combined sewers that carry both wastewater and stormwater. The flow is directed to wastewater treatment plants where the effluent is treated to remove solids, organic matter, and contaminants before it is discharged under regulatory limits. In many regions, stormwater has its own separate system, while older cities may still operate combined networks.

Wastewater treatment generally follows several stages. Primary treatment removes settleable solids. Secondary treatment uses biological processes to degrade dissolved organic matter and reduce nutrient loads. Tertiary treatment, where required, targets remaining nutrients or pathogens, producing higher-quality effluent. The sludge produced during treatment is thickened and processed further, typically through digestion and dewatering, before disposal or reuse as biosolids where permitted.

Public health and environmental protection depend on reliable kloakk systems. Proper operation reduces odors, prevents contamination of drinking water sources, and minimizes the spread of disease. In older urban areas, issues such as infiltration, exfiltration, or combined sewer overflows during heavy rainfall can challenge system performance.

Governance and financing for kloakk systems usually fall to municipalities or regional water utilities and are regulated by environmental authorities. System planning and upgrades are influenced by urban growth, climate change, and evolving water quality standards. The word kloakk traces to Latin cloaca, meaning sewer, via Dutch kloak and related European forms.