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Nelson Pi, MS, EIT environmental engineer

Overview • Projects – Dry Wells for Stormwater Management – Wastewater Treatment Plant Design – LADWP Stormwater Infiltration – Comparative LCA – Flat Roof Types – Sustainable School Design – Low Impact Development

Dry Wells for Stormwater Management

• The use of dry wells in other states is found to be a viable stormwater management option. • There is a concern that the use of dry wells will introduce contaminants to groundwater because of their limited treatment capabilities.

Current drywell systems provide minimal treatment opportunities.

Acceptance in California may rest on pretreatment methods.

Bioretention areas and other LID practices leading to dry well inlets can provide a significant amount of pollutant and sediment removal.

• Findings from the literature review and data analysis are currently being reviewed for publishing on the web. • A fact sheet pertaining to dry well regulations and guidelines is also under a final review for printing. • Further research will be conducted through a project funded by a Prop. 84 grant.

• Design drawings were created following site visits. • The following are 60% design drawings for the project.

Wastewater Treatment Plant Design

Convert wastewater to drinking water

• Applied engineering formulas to size tanks and pipes to meet sufficient detention times based on drinking water requirements • Complete design of primary, secondary, and tertiary treatment systems

• Each individual element was combined into a coherent whole. • Our design team received the highest score in the class.

LADWP Stormwater Infiltration

• Conventional storm water management systems, already in place, have been unsuccessful in managing runoff generated on site. • Runoff generated also contributed to flooding of nearby streets.

• Leading a team of 8 other engineers, the goal was to provide LADWP with an alternative stormwater management system which would manage runoff on site and provide groundwater recharge.

Change an area with minimal runoff retention capabilities, to‌

A more aesthetically pleasing stormwater management system.

• The detention basin was designed to accept additional runoff from other areas to maximize the infiltration potential and provide flood control. • The use of vegetated swales and bioretention areas would remove contaminants found in runoff to meet state anti-degradation laws.

Comparative LCA – Flat Roof Types

• Within engineering we often have several solutions to a problem. • A life cycle assessment provides additional insight that will aid the decision making process.

Which system has the best performance?

• Alternative roof systems have been suggested to reduce energy consumption and curb the effects of climate change. • Based on construction materials, energy inputs, and CO2 output each alternative was analyzed.

Total Primary Energy Comparison 1,200,000

Global Warming Potential 50000 45000


40000 35000


30000 25000


20000 400,000

15000 10000

200,000 5000 0

0 Total Primary Energy (MJ)






Analysis of environmental impacts of each roof system.




• Utilization of LCA programs to gather environmental impacts of each component. • Data was compiled and modeled in Excel to clearly show the results of the analysis.

Sustainable School Design

• There is a current shift towards green design and sustainability. • This project implements green engineering practices for a modular school design for the Save the Children foundation.

• In order to meet client needs, research was conducted to learn about the culture, school system, customs, and climate. • These elements were incorporated into a conceptual design with sustainability in mind.

Maximize the use of natural and renewable resources

Conceptual model reflecting client needs

Improved rendering to better reflect concepts

• The final design of the sanitation system would be completed by a team of wastewater engineers. • Requirements from the International Building Code were followed.

• The school was to be located in a remote area with little water resources. • In order to maximize the drinking water supply, a waterless sanitation alternative had to be utilized. • All plans and specifications were completed in Revit, a program I was unfamiliar with at the time.

A composting toilet facility

A low flow hand wash and grey water treatment station

• We created a system which would minimize water use, maintenance, and convert waste to a resource which could be utilized by the community.

Low Impact Development

• Traditional methods of storm water management have led to a reduction in water quality and alterations to the natural environment.

• Research in low impact development would aid in returning urban environments to their natural hydrologic conditions.

Onsite stormwater management with contaminant removal capabilities

• Based on findings from a literature review, the most suitable LID practices were implemented in a detention basin in Elk Grove. • A visual representation of the modified basin was constructed in Google Sketchup.

Vegetated swales, bioretention areas, dry wells, and a constructed treatment wetland would be implemented in the basin.

• The LID practices used accounted for site conditions and the storm water characteristics found in the area. • Full treatment capabilities would be reached at lower flows, while it would return to its function as a detention basin for higher flows.

• The system would increase the likelihood of contaminant removal as runoff flows through the vegetated swales, treatment wetland, and bioretention areas prior to infiltration through dry wells. • The modified basin would also provide educational and recreational opportunities for the community while expanding the natural habitat.

Thanks for taking a look!

Nelson Pi 714-851-6265

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