Community Sewer Systems

What is Eutrophication?

Eutrophication is plant overgrowth in domestic waterways.

green grass on water
Photo by cottonbro on

Wastewater contains nitrate and phosphorus which are nutrients that plants need to grow. Usually, nutrients are good things, but growing population density can result in too much of a good thing being deposited into streams, rivers, and other waterways. When this happens, plant life takes over – crowding out the habitats of fish and other aquatic life. As these plants die and rot, they can change water PH and bacterial levels.

To stop eutrophication, wastewater treatment systems need to greatly reduce or eliminate the amount of nitrate and phosphorus which they return to the watershed in their effluent. Governmental agencies set concentration maximums and enforce them through regular testing.

For the most part, nitrate and phosphorus can be reduced below regulatory thresholds through biological processes known as denitrification and mineralization. Advanced wastewater treatment systems use highly concentrated populations of beneficial bacteria to digest nitrate and phosphorus. The former is then released as nitrogen gas and the latter, collects in the tank as part of the sludge.

Even after advanced treatment, trace amounts of nitrate and phosphorus can frequently be found in wastewater effluent. Where mandated, further treatment can completely prevent even these from reaching the watershed.

If you’re in need of a wastewater system that will prevent eutrophication, let’s talk!

What are the 3 Stages of Wastewater Treatment?

Wastewater can be treated in up to three stages generally known as primary, secondary, and tertiary treatment. Here’s what’s involved in each of these stages:

  • Primary Treatment

    In this stage, heavy solids and grease are separated from the raw sewage through gravity and buoyancy respectively. A conventional septic tank is an example of primary treatment.

  • Secondary Treatment

    The wastewater that leaves a septic tank or other primary treatment apparatus is still pretty contaminated with suspended solids and toxic chemicals such as ammonia. Secondary treatment systems use oxygen to facilitate natural digestion of contaminants by micro organisms already present in the wastewater. All municipal systems use secondary treatment.

  • Tertiary Treatment

    Even though much cleaner, water leaving secondary treatment can still pose somewhat of a threat to the environment. To ensure complete protection of aquifers and watersheds, wastewater effluent can enter a third treatment stage. Tertiary treatment usually involves some sort of natural or chemical filtration/sanitization. Examples of tertiary treatment are constructed wetlands or drip irrigation fields.

Our systems use all three stages of wastewater treatment to equip you for responsible growth. Let us show you how!

Drip irrigation systems are an efficient and proven technology many communities use to recycle and dispose of treated wastewater. The effluent is applied to the soil slowly and uniformly from a network of narrow tubing, placed in the ground at shallow depths of 6 to 12 inches in the plant root zone.

Because water is such a precious commodity, recycling wastewater can have both economic and environmental benefits for communities. Reusing wastewater to irrigate land can help protect surface water resources by preventing pollution and by conserving potable water for other uses. This is particularly important where community water supply sources rely on wells. The more water that is pumped from wells and discharged as effluent into a stream or other surface water, the less will be available to recharge aquifer or ground water sources upon which future well water supplies rely.

Another benefit of applying wastewater to the land is that the soil provides additional treatment through naturally occurring physical, biological and chemical processes. Irrigating with wastewater also adds nutrients and minerals to soil that are good for plants and it helps to recharge valuable groundwater resources.

Residential developments with low building density required by septic drain fields contribute to an undesirable sprawl and limit land available for playgrounds, hiking trails and other open space amenities. Spray systems, while superior to septic, can also limit land use since they produce aerosols which require large buffer zones.

Community sewers that use drip irrigation consolidate undersoil treatment into one region of the subdivision. This region can provide a visually appealing common area for the development. Achieving higher land use densities with desirable open spaces are important and shared goals of land use planners, environmentalists and developers alike.

Soil reuse systems require less monitoring and thus lower operating costs when compared to surface discharge.

Additionally, subsurface discharge expedites acquisition of state and county permits by addressing potential concerns of downstream property owners removing any reason for them to contest approval.

Beneficial reuse through drip irrigation is just another way we’re equipping responsible growth. Click the button below to see how we can equip you.