On-Site Wastewater Treatment Systems (Septic System Design)

Remote facilities such as residences, businesses, and camps that are far from centralized municipal sewage treatment systems generally treat and dispose of their wastewater on site. Such on-site wastewater treatment systems (OWTS) are also known as “septic systems” and are regulated through the federal Clean Water Act by state and regional agencies. When adequately treated, waste water can be re-used for irrigation or other non-potable uses and help obtain Leadership in Energy and Environmental Design (LEED) certification from the U.S. Green Building Council (USGBC).

The Earth Systems group of companies provides services to design septic systems for a wide variety of facilities. We can conduct percolation tests to evaluate the capacity of soils or bedrock to absorb waste water, and geotechnical engineering investigations to evaluate adverse impact on groundwater, foundations or slopes. We prepare design documents for septic systems including septic tanks, leach fields, seepage pits, and advanced treatment including both secondary and tertiary treatment. Environmental sampling of wastewater and groundwater can also be provided.

Representative Project

Camp Emerald Bay, Santa Catalina Island,
Los Angeles County, California – Master Plan

Camp Emerald Bay is a large recreation facility used by a wide variety of youth organizations. Numerous cabins, a dining hall, an aquarium building, community restrooms and showers, tent sites, a beach and dock comprise the facility. Because demand and use continue to increase, a master plan was developed which entails increased and improved infrastructure, new recreation buildings, and a new wastewater collection, treatment, and reuse system.

Earth Systems Southern California was retained to investigate the geotechnical conditions at the site and provide conclusions regarding feasibility of percolation for treated wastewater. Our geotechnical engineering investigation entailed exploratory subsurface pits, soil borings and installation of groundwater monitoring wells, laboratory testing of soil samples, and slope stability analyses. Our septic/wastewater percolation study involved fifteen shallow percolation tests in a range of geologic strata. During the septic system design process, we evaluated and configured four overlapping or interconnected wastewater systems with septic tanks, grease traps, and leach fields. Our services also include periodic groundwater and aquarium effluent monitoring as required by the State of California.