Case Studies

Residential Land Development

Project Summary

New Home Subdivision Wastewater Treatment Plant

  • Application: New Home Subdivision
  • Year of Completion: 2003
  • System Type: Tertiary Wastewater Treatment, Sub-Surface Discharge

Residential Land Development Case Study Large I...

The Problem

The land developer wanted to construct more than one hundred homes on residential sized lots. The property was not serviced with infrastructure including sewer pipelines and the municipality required the construction of an on-site wastewater treatment plant to treat the domestic wastes as a condition of property development.

Since there was no receiving body of water that would allow a surface water discharge, the effluent from the wastewater treatment plant would have to be discharged sub-surface through a tile field. The land around the subdivision has been intensively farmed for many years. The groundwater was high in nitrates and the governmental authorities would not allow the effluent discharge from a conventional wastewater treatment plant.

The developer wanted a wastewater treatment plant that did not require any outside holding tanks, lagoons or other containment. In order to maximize land use, the plant had to be compact, reliable and blend into the local environment. Local residents wanted an unobtrusive facility that does not give off unpleasant odours.

The Seprotech Solution

After an extensive evaluation and selection process, Seprotech was chosen to supply a ROTORDISK® wastewater treatment plant. The facility is extremely compact and the building incorporates many of the design features and materials of the locally surrounding homes. As a neighborhood having many small children, parents appreciate that the plant is secure, hygienic and without dangerous open ponds or lagoons. The plant blends seamlessly into the environment and most people would never guess that this architecturally designed building is actually a wastewater treatment plant.

Seprotech designed a tertiary wastewater treatment plant process that would produce an effluent that reduced BOD5 and TSS to <15 mg/l respectively and total nitrogen (TN) of <5 mg/l.

The treatment process is summarized as follows:
  • Wastewater is pumped from a wetwell to a primary clarifier.
  • The wastewater flows by gravity to the Rotorzone of the ROTORDISK®.
  • The first two stages of the Rotorzone remove most of the BOD and TSS.
  • The third and fourth stages of the Rotorzone are for nitrification. Nitrification is a bacteriological conversion of ammonia nitrogen to nitrates.
  • The wastewater exits the rotorzone and enters an anoxic ROTORDISK® zone where nitrates are oxidized into nitrogen gas. The anoxic condition is achieved by covering the RBC shaft and media.
  • The wastewater flows into a final clarifier and is discharged to a compact leaching bed.

The treatment plant incorporates many state of the art features that allow the developer to meet stringent effluent discharge standards. The major advantage to the developer is that the plant could be constructed at a much lower cost than individual septic systems together with significant savings in the development potential of the land. Currently operated by third parties, this wastewater treatment plant requires approximately three hours of routine inspection, routine maintenance and effluent testing per week.

Applications: Residential Property Development