Emails (excerpted), responses to PolitiFact Texas, D. Lauren Ross, owner, Glenrose Engineering, Inc., Austin, Jan. 10, 2013
total suspended solids (TSS)
This can be thought of as a measure of water clarity. On average, the effluent had lower TSS (better clarity).
(Ross responses in bold)
LCRA data (http://www.lcra.org/water/quality/state.html) shows that the clarity of the Colorado River below Austin is significantly lower than in Lake Austin. See for example, August 2012. Lake Austin is transparent to a depth of 1.77, where the Colorado River at Webberville is only transparent to a depth of 0.42 feet.
Form of nitrogen that can be toxic to aquatic life in high enough concentrations but more typically serves as a nutrient for plant and algae growth. Effluent had higher concentrations than the lake water.
Ammonia is converted to nitrate nitrogen in the wastewater treatment process. While ammonia is more toxic to fish, nitrate is an equally powerful contributor to plant and algae growth and eutrophication. Monitoring only ammonia, rather than nitrate or total nitrogen, significantly underestimates the contribution to water quality degradation from Austin’s wastewater effluent discharges.
total phosphorus (TP)
Another nutrient needed for plant and algae growth. Too much can potentially over-stimulate growth. Only two of the Austin treatment plants monitor phosphorus, and the effluent had higher concentrations.
Similar to monitoring for ammonia rather than nitrate or total nitrogen, failing to monitor for wastewater effluent’s most significant contributions to stream degradation hides the true impact of Austin’s wastewater effluent on downstream water quality.
Measure of how acidic or alkaline the water is (scale of 0 to 14). Generally want to be in midrange without extremes. Both effluent and lake water were in reasonable ranges.
Breathed by fish and other aquatic organisms. Effluent and lake values are acceptable. Low levels can naturally occur at/near the bottom of lakes (zeroes in the lake data minimums), but raw drinking water is not drawn from that depth generally.
Type of bacteria used as an indicator of water quality. Found in the intestinal tract of warm-blooded organisms, it’s presence can indicate fecal contamination and the potential for waterborne disease. The effluent generally had lower E. coli numbers.
These are only a fraction of water quality parameters that could potentially be compared between the two water types, but the reality is that available data allows only a handful to be evaluated. With the parameters above, the effluent tends to be clearer and lower in bacteria levels, while the lake water is generally lower in nutrient concentrations. Dissolved oxygen and pH were comparable between the two types. So with respect to the statement that the effluent quality is higher than the source water, for some things it’s true, for others it’s not.
The parameters for which Austin’s wastewater effluent quality is poorer than Lake Austin water are all of the ones that are significant contributions to stream degradation. Austin fails to adequately monitor the pollutants that it contributes to Colorado River degradation. The differences between the wastewater effluent quality and these parameters are significant differences, and they make a difference in the quality of the entire flow of the Colorado River, as indicated by LCRA monitoring results.
I can provide the following evidence that Austin's wastewater effluent quality is not higher than Lake Austin water quality.
This is a link to LCRA water quality monitoring data: http://www.lcra.org/water/quality/state.html. Open the reports for August 2012 or June 2012. Go to page 6 of either of these reports. The top part of the page is measurements, the bottom a summary status. Looking first at Status for June, you can see that where Lake Austin is "low" for nitrogen, the Colorado below Austin is "high/crit". That is true for both June and August.
Going to the top table on the same page, nitrogen in Lake Austin is 0.008 milligrams per liter. Colorado River below Austin is 8.8 milligrams per liter. That is an increase by a factor of more than a thousand. The concentrations differences between Lake Austin and the Colorado River downstream from Austin's wastewater effluent discharges are similar for August 2012. The relationships between phosphorus concentrations in Lake Austin compared to below the City's discharge are also similar.
So there could be other sources for that nitrogen and phosphorus increase other than the City's wastewater effluent. But these were both dry months, so no storm runoff. Storm runoff nutrient concentrations are not as high as those Colorado River measurements.
This is the link to the City of Austin wastewater effluent self-reporting data: http://www.austintexas.gov/department/wastewater-reports-discharge-monitoring-reports-dmr. If you can decipher the report for June 2012, not an easy task, you will see that there are very few measurements. There is no information on either nitrogen or phosphorus. So the City isn't measuring the constituents required to compare wastewater effluent to Lake Austin to even know whether the water they are discharging is a clean as what they are pulling out of the lake.
The reported measurements for ammonia nitrogen are <0.2 mg/l, 1.8 mg/l (May 2012), <0.1, and 0.1 mg/l (June 2012). All of these measurements in the effluent are significantly higher than the measurements for total nitrogen (of which ammonia would be only a part), indicating that Austin's wastewater effluent is polluted with nitrogen compared to the water they are pulling out of the Lake.
Attached is the City's wastewater permit from TCEQ. Page 2 of the file gives the allowed discharge concentrations. Under this permit the City is allowed to discharge ammonia nitrogen at a concentration of 5 (7 day average), 10 (daily maximum) or 15 (single grab sample) milligrams per liter. There is nothing in the terms of their permit with TCEQ indicating that Austin's wastewater effluent is better than the quality of Lake Austin water.
Finally, there is lots of evidence that the City fails to meet criteria 4 on page 2 of the permit: "There shall be no discharge of floating solids or visible foam in other than trace amounts and no discharge of visible oil. Attached are photographs of foam discharge from the South Austin Regional Plant. These foam discharges have often occurred.