AWWA MTC64610

The Big Bear Area Regional Wastewater Agency (BBARWA) recently completed a study of advanced waterreclamation as a means to augment existing potable water supplies for the residents and visitors of Big BearValley. Potable water is provided by local groundwater (GW); during periods of drought or prolonged dryweather water demand can exceed supply. The use of recycled water, treated to a high quality via an advancedtreatment process and artificially recharged, has been identified as the best means of supplementing the nativeGW supply. The advanced treatment proposed at the BBARWA Facility consists of microfiltration (MF),reverse osmosis (RO), followed by ultraviolet disinfection (UV) with advanced oxidation. While backwashwaste produced from MF/UF facility can be recycled back to the headworks of the BBARWA wastewatertreatment facility, the concentrate (reject) flow from the RO needs to be properly disposed. In this paper, sevendifferent treatment methods were evaluated to dispose of concentrate from a future 1.2-mgd recycled waterfacility: constructed wetlands, electrodialysis reversal (EDR), enhanced RO treatment, mechanical and solarevaporation, Vibratory Shear Enhanced Process (VSEP) and wastewater effluent blending. All treatments wereevaluated on a paper study basis, except VSEP, which was tested on-site using concentrate from the MF/ROpilot system. The study included siting solar evaporation and constructed wetlands facilities in Lucerne Valley25 miles from Big Bear Valley (BBV), where BBARWA currently land applies their wastewater effluent. LV was selected in thisevaluation, because it minimizes public perception issues (i.e., mosquito, vector issues), reduces evaporationand wetland sizes due to higher evaporation/evapotranspiration rates in this lower altitude region and leavesspace in WWTP for future plant expansion. Study results showed the most cost effective approach is to combineRO concentrate volume reduction using VSEP or EDR with evaporation ponds or constructed wetlands in theLV. VSEP is preferred over EDR due to the ability to produce a high quality permeate that can be blended withBBARWA effluent and some fraction of RO concentrate while still meeting land application guidelines.Constructed wetlands offer the potential to better manage wildlife issues associated with elevatedconcentrations of selenium but have not been demonstrated to be sustainable using a zero liquid dischargeapproach. Includes 4 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

03/01/2007

Number of Pages:

17

File Size:

1 file , 340 KB