• Corporate HQ, NY
  • Melville, NY
  • Iselin, NJ
  • Ossining, NY
  • Mount Laurel, NJ


CSOs are prevalent in areas with sewer systems that combine wastewater with storm runoff in the same pipes, a condition affecting nearly 4 percent of U.S. cities. Normally, this combined wastewater and rainwater from storm drains is treated at sewage treatment plants before being discharged into natural water bodies. But during heavy rainstorms, the capacity of treatment plants can be quickly overwhelmed.  To prevent sewer backup into streets and buildings during these times, a combined sewer system is designed to discharge excess wastewater and rainwater directly into water bodies, releasing raw sewage into rivers, lakes, streams and other collection points.

HAKS works with public municipalities and the private sector to mitigate combined sewer systems that cause potentially harmful and environmentally damaging CSOs. Our CSO abatement services include upgrade, renovation and rehabilitation of existing infrastructure and process equipment; demolition, rehabilitation and reconstruction of existing floatable control  facilities at CSO regulator sites; dewatering system installation and cutting and removal of existing sewer roofs; diversion sewer design and sewer construction using trenchless techniques; soil borings and permeability testing according to protocols  developed by the New York City Department of Environmental Protection Green Infrastructure group; urban bioswales for detention and retention of storm water runoff prior to discharge into combined sewer systems; comprehensive sewer outflow abatement planning and construction management, including constructability review, REI, construction inspection, preparation and review of final shop and working drawings and as-built contract drawings and other related services.