The pros and cons of using nanofiltration in lieu of reverse osmosis for indirect potable reuse applications

The scope of this study was directed to examine different wastewater treatment technologies (activated sludge, trickling filter, nanofiltration, reverse osmosis) at full-scale facilities in Arizona and California leading to indirect potable reuse and their capability to remove pharmaceuticals. Additionally, the fate of selected pharmaceuticals was studied during soil-aquifer treatment (SAT) at sites where secondary and tertiary treated effluents are used for subsequent groundwater recharge. Facilities employing longer detention times during treatment (nitrifying and denitrifying plants) showed significant lower effluent concentration for analgesic drugs as compared to trickling filter or activated sludge facilities applying shorter detention times. A similar trend was observed for the lipid regulator gemfibrozil, which was significantly removed in denitrified effluents, whereas a trickling filter treated effluent exhibited concentration of 1,235 ng/L. Antiepileptic drugs, such as carbamazepine and primidone, showed no dependency on the wastewater treatment applied. None of the investigated drugs was detected in tertiary treated effluents after nanofiltration or reverse osmosis. After SAT, analgesic/anti-inflammatory drugs were efficiently removed after retention times of less than 6 months and remaining concentrations were near or below the detection limit of the analytical method. A high potential for biodegradation was also observed for anti-inflammatory drugs in groundwater recharge systems. The antiepileptics carbamazepine and primidone represented the most dominant of all investigated drugs in well treated domestic effluents (nitrifying/denitrifying plants). Removal of carbamazepine and primidone did not seem to occur during travel times of more than 6 years in the subsurface.

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Using a membrane bioreactor/reverse osmosis system for indirect potable reuse

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0127 ◽

2001 ◽

Vol 1 (5-6) ◽

pp. 303-313 ◽

Cited By ~ 12

Author(s):

J. Lozier ◽

A. Fernandez

Keyword(s):

Drinking Water ◽

Reverse Osmosis ◽

Membrane Fouling ◽

Membrane Bioreactor ◽

Municipal Wastewater ◽

Secondary Effluent ◽

Potable Reuse ◽

High Calcium ◽

Indirect Potable Reuse ◽

The City

The City of McAllen, Texas, with the assistance of CH2M HILL, has pilot tested an integrated membrane bioreactor (MBR)/reverse osmosis (RO) treatment train to reclaim municipal wastewater to a quality suitable for use as a new drinking water supply in the process called indirect potable reuse. Previous testing by the City (Phase 1) demonstrated the applicability and cost of microfiltration (Memcor and ZeeWeed systems) to enhance the quality of secondary effluent for subsequent treatment by RO and the feasibility of a membrane bioreactor system (ZenoGem) to produce RO feedwater directly from minimally processed sewage. Phase 2 testing, reported on in this paper, is designed to demonstrate reliable operation of MBR/RO treatment for processing screened, degritted sewage and that the effluent from such a train can meet all federal primary and State secondary drinking water regulations and comply with anticipated State requirements for indirect potable reuse. Results show the ZenoGem process to be reliable, require minimal operator attention and maintenance, produce an effluent that can be processed by RO with little fouling and that easily exceeds the City's current effluent discharge requirements relative to BOD, TSS and ammonia. The ZenoGem permeate quality exceeds RO feedwater criteria for turbidity and silt density index and RO system performance confirms minimal membrane fouling by particles. However, the high calcium hardness and phosphate levels in the City's wastewater (and ZenoGem permeate) caused mineral precipitation within the RO system when operated at higher recoveries. Precipitation can be controlled, however, by increased acidification of the RO feedwater.

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“MICROFILTRATION AND REVERSE OSMOSIS PILOT TESTING FOR INDIRECT POTABLE REUSE AT THE UNIVERSITY AREA JOINT AUTHORITY”

Proceedings of the Water Environment Federation ◽

10.2175/193864701790864656 ◽

2001 ◽

Vol 2001 (13) ◽

pp. 93-107

Author(s):

Jason D. Wert ◽

Brian L. Book ◽

Stephen T. Welch ◽

Steven M. Siegfried

Keyword(s):

Reverse Osmosis ◽

Pilot Testing ◽

Potable Reuse ◽

Indirect Potable Reuse ◽

The University

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Screening health risk assessment of micropullutants for indirect potable reuse schemes: a three-tiered approach.

Water Science & Technology ◽

10.2166/wst.2007.831 ◽

2007 ◽

Vol 56 (11) ◽

pp. 35-42 ◽

Cited By ~ 10

Author(s):

C. Rodriguez ◽

A. Cook ◽

P. Van Buynder ◽

B. Devine ◽

P. Weinstein

Keyword(s):

Reverse Osmosis ◽

Health Risks ◽

Organic Contaminants ◽

Recycled Water ◽

Treatment Technology ◽

Potential Health ◽

Trace Organic Contaminants ◽

Potable Reuse ◽

Tiered Approach ◽

Indirect Potable Reuse

Indirect potable reuse schemes are an important consideration in the sustainable management of scarce water resources. However, communities still hold real concerns about the potential health risks of micropullutants in recycled water entering their potable water supply. Microfiltration or ultrafiltration followed by reverse osmosis is currently the standard treatment technology for potable use of recycled water. Nevertheless, membranes are not 100% efficient in the removal of trace organic contaminants and the potential health risks of these micropullutants need to be assessed. The aim of this paper is to present a three-tiered approach for the preliminary assessment of micropullutants in recycled water. A risk quotient is calculated by comparing measured concentrations against benchmark values. Tier 1 corresponds to regulated chemicals; the maximum contaminant level in drinking water is used as benchmark value. Tier 2 corresponds to unregulated chemicals with toxicity information; slope factors or risk specific doses are used to calculate benchmark values. Tier 3 corresponds to unregulated chemicals without toxicity information. The “Threshold of Toxicological Concern” concept is used to calculate benchmark values. The characterization of chemicals of concern following reverse osmosis in a water reclamation plant and the application of the three-tiered approach for the evaluation of the potential health risks is presented.

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Treatment of Trace Organic Compounds by Membrane Processes: At the Lake Arrowhead Water Reuse Pilot Plant

Water Science & Technology ◽

10.2166/wst.1999.0603 ◽

1999 ◽

Vol 40 (4-5) ◽

pp. 293-301 ◽

Cited By ~ 3

Author(s):

Bruno B. Levine ◽

Kapal Madireddi ◽

Valentina Lazarova ◽

Michael K. Stenstrom ◽

Mel Suffet

Keyword(s):

Pilot Plant ◽

Water Reuse ◽

Ultra Violet ◽

Treatment Efficiency ◽

Small Molecular Weight ◽

Potable Reuse ◽

Low Concentrations ◽

Neutral Compounds ◽

Indirect Potable Reuse ◽

Trace Organic

Organic and trace organic performance data for ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) at the Lake Arrowhead water reclamation pilot plant are analyzed to determine the treatment efficiency of these processes in an indirect potable reuse design. Four organic parameters were studied: dissolved organic carbon (DOC), ultra-violet absorbance at 254 nm (UV-254), SUVA and base neutral analysis (BNA). UF and NF removed the larger compounds from the influent, but had no significant impact on the base neutral fraction with the exception of sterols. The RO process removed DOC and UV-absorbance compounds from the effluent to their respective detection limits. Base neutral compounds were significantly removed by RO, leaving at extremely low concentrations small molecular weight compounds, indicating indirect potable reuse is technically feasible.

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An Australian perspective on DPR: technologies, sustainability and community acceptance

Journal of Water Reuse and Desalination ◽

10.2166/wrd.2015.180 ◽

2015 ◽

Vol 6 (3) ◽

pp. 355-361 ◽

Cited By ~ 3

Author(s):

Ian B. Law

Keyword(s):

Water Supply ◽

Recent Work ◽

Western Australia ◽

Community Education ◽

Water Recycling ◽

Potable Reuse ◽

Community Acceptance ◽

Indirect Potable Reuse ◽

Direct Potable Reuse

Australia has had guidelines in place for water recycling (for all uses other than potable reuse) since 2006. These guidelines were extended in May 2008 to cover potable reuse and have since been applied to two potable reuse schemes – one in Brisbane (Queensland) in 2011 and the second in Perth (Western Australia) in 2013. These guidelines cover both indirect potable reuse and direct potable reuse (DPR) and outline the steps that must be followed in the planning and validation of such schemes. This paper summarizes: (i) recent work carried out in Australia on treatment trains and technologies suitable for DPR; (ii) sustainability considerations of DPR and how it compares with other water supply options; and (iii) developments in community education and engagement in the potable reuse space.

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