Jon Hedegard

Director of Waste Water

Tel: 956-440-6515


Welcome to the Wastewater Department of the Harlingen Waterworks System. We are the primary source for treatment of your domestic wastewater (sewer). The main reason a wastewater treatment facility is needed is to clean used water and sewage so it can be returned safely into the environment. Producing clean water is the primary goal of a wastewater treatment facility.

The beginning process of the wastewater treatments comes from homes – any household wastes from toilets, sinks, baths, and drains. As well as industry, schools and businesses – chemicals and other wastes from factories, food service operations, airports, shopping centers, etc. Also storm runoff and groundwater – water that collects in streets drains and groundwater that enters into the sewer system. The wastewater travels through the sewer system under the city that leads it towards the wastewater treatment facilities. Once the wastewater has reached the wastewater treatment facilities, it gets treated usually in two steps.

The Primary Treatment removes 40 – 50% of the solids from the wastewater. The wastewater passes through bar screens, this process that allows water to pass, but not trash (such as rags or sticks). The trash is collected and properly disposed of. Next the grit chamber, which is a large tank that slows down the flow of water in order to allow the sand, grit and other heavy solids to settle to the bottom, then later removed. Then to a Primary Sedimentation tank, this allows the smaller particles to settle.

The Secondary Treatment completes the process, so the 85 – 90% of the pollutants are removed. It starts by reaching an Aeration Tank to supply large amounts of air to the mixture of wastewater, bacteria and other microorganisms. Oxygen is needed to help the microorganisms grow, which consume harmful organic matter in the wastewater. The wastewater then reaches a Secondary Sedimentation tank, which allows the microorganisms and solid waste to form clumps and settle. The last step is a disinfectant, such as chlorine is added to the wastewater before it leaves the treatment facility. The disinfectant kills disease-causing organisms in the water.

After treatment, the water can be returned to nearby waterways. It can also be used on land for agriculture and other purposes.