Wastewater As A Water Resource design and Operation of an Integrated Biofilter wastewater Treatment and Reuse System
Open Access
- Author:
- CAMERON, Robert D
- Graduate Program:
- Horticulture
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 25, 2012
- Committee Members:
- Robert Berghage Jr., Dissertation Advisor/Co-Advisor
Same, Committee Chair/Co-Chair
Edmund Jay Holcomb, Committee Member
Dan Thomas Stearns, Committee Member
Allan Gunnar Sonsteby, Committee Member - Keywords:
- living walls
green roofs
energy conservation
wastewater
water resources
living architecture
green architecture - Abstract:
- The modern method of managing wastewater requires removal from the source as quickly as possible to a centralized treatment system before discharging to a receiving body of water. Although this method is in large part responsible for the near elimination of the major outbreaks of water borne diseases in developed nations, the approach is unsustainable due to infrastructure costs and its ineffectiveness to eliminate many organic compounds. An alternative approach is to regard wastewaters as a resource. An effective and cost efficient decentralized management system was designed to convert wastewater into a water resource. Constructed wetlands, living wall, and living columns were integrated into a single system with a footprint less than 15 square feet. Designated an integrated biofilter (IBF); the system treated up to 50 gallons of gray water or black water in a batch process. Analyses for 26 parameters demonstrated the IBF capable of decreasing levels of pollutants such as organics (BOD) and surfactants by 99% in 24 hours and meeting applicable discharge limits. Existing decentralized management systems such as constructed wetlands require significantly longer detention times to attain similar rates of attenuation. Continuous flow of wastewater through the IBF was compared to intermittent flow to compare rates of pollutant attenuation. Cycling the wastewater through the IBF for four 1 hour intervals was as effective in removing pollutants as continuous flow. Components of the IBF were also evaluated to determine contribution of each. Results demonstrated the effectiveness of the entire system was superior to the attenuation achieved by the sum of the individual components. Green roof biofilters were also evaluated for effectiveness in reducing pollutants in gray water. Potential exists to integrate green roofs with IBFs. The IBF was also evaluated to determine the potential to manage wastewater as a water resource. Energy studies were conducted using replicate buildings at the Pennsylvania State University’s Center for Green Roof Research. IBFs were positioned on the south wall of two buildings. Impacts to the south wall temperature profile and the buildings’ energy use for air conditioning were evaluated, while gray water was cycled through the IBFs. Decreases of south wall exterior mean temperatures up to 68% and internal south wall temperatures up to 28% were observed. Energy usage for cooling decreased by 16%. IBFs also affected the timing of peak temperatures. Cycling of gray water through a green roof was also studied for the impact on building temperature and energy usage. Although temperature reductions were observed, no significant reduction in energy use was found when compared to a green roof without gray water application. Treated gray water was applied to a traditional, asphalt shingle roof to evaluate potential to reduce building envelope temperatures and resulting energy use for cooling. Results demonstrated a 52% reduction to the temperature outside the ceiling insulation and reduction of energy use by 11% compared to a control building. Temperature reductions were superior to those achieved with green roofs. The potential to incorporate IBFs into residences as functional architecture was evaluated. Applications included living showers and living window wells. Food crops such as herbs and tomatoes were cultivated in IBFs with gray water. No adverse impacts on growth were observed. The IBF wastewater management system was demonstrated to be effective at attenuating pollutants and utilizing wastewater as a valuable resource. Avoiding disposal costs associated with centralized waste water treatment plants, while obtaining savings from reduced energy expenses, make wastewater management with an IBF a viable alternative.