Treatment performance of advanced onsite wastewater
treatment systems in the Otsego Lake w
SUNY Oneonta Biological Field Station
1 Funding provided by NYSDEC grant #49298.
Treatment performance of advanced onsite wastewater
treatment systems in the Otsego Lake watershed
2008-20111
Submitted by:
Holly Waterfield
SUNY Oneonta Biological Field Station
5838 State Highway 80
Cooperstown, NY
13326
Funding provided by NYSDEC grant #49298.
Treatment performance of advanced onsite wastewater
atershed
EXECUTIVE SUMMARY
This report documents the treatment performance of four advanced onsite wastewater
treatment systems based on monitoring during the summers of 2008 through 2011. All four
systems are installed in the Otsego Lake watershed; three were installed as part of a NYS DEC
grant to demonstrate the use of advanced onsite wastewater treatment systems. Three systems
have been monitored since 2008 (Waterfield and Kessler 2009, Waterfield 2010, Waterfield
2011); OWTS 1 and OWTS 2, funded by the grant, and the UIC system (serving BFS Upland
Interpretive Center). Another system, also funded by the grant, was installed in the spring of
2009 at the BFS Thayer Farm; this system serves three buildings; the Hop House, Boat House,
and a rented residence. Many of these enhanced treatment technologies are new the region, and
thus are unfamiliar to industry professionals, regulators, and residents. For this reason, a DEC
grant was sought and obtained to fund a demonstration project to install and monitor the
treatment performance of six shared advanced treatment systems. The scope of the grant has
since been amended, changing the total number of treatment systems to four, with the last
installed in early 2011 to serve SUNY Oneonta’s newly renovated Cooperstown Campus, which
houses the Biological Field Station and the Cooperstown Graduate Program. The grant did not
fund the installation of the system, though the treatment technologies used were chosen by the
demonstration project’s coordinators.
Treatment performance was assessed based on the following analyses: biochemical
oxygen demand (BOD or CBOD), total suspended solids (TSS), nitrate (NO3), ammonium
(NH3), and total phosphorus (TP). Systems were sampled a total of about 31 occasions, though
all four systems weren’t necessarily sampled on each collection date. Detailed analysis of each
system’s performance is provided in the System Performance, Operation, and Maintenance
section of the 2008-2011 report. Overall, treatment systems performed well, but mainly because
they were actively managed and serviced by qualified professionals. The systems incorporating
textile filters received the most consistent use with the incoming effluent being of typical
household strength (higher than the other systems monitored). Outgoing effluent from these units
was of the highest quality, achieved the best nitrogen transformation rates, and was the least
variable of the systems monitored. The aerobic treatment unit (ATU) serving the UIC produced
effluent of consistent quality, though the system saw very low use compared to its designed
capacity. It handled typical UIC functions and events (field trips, workshops, etc.) and long
periods of low use very well without compromising effluent quality. The foam filter’s treatment
was most variable of the four systems and produced effluent of lower quality than the other units.
The configuration and dosing regime of this system may play a role in the variability observed
throughout this monitoring program.
In the end, most treatment performance issues were improved by communicating with the
trained service provider contracted for each system. As the manufacturer’s recommend, regular
maintenance is needed in order for these systems to operate as they are intended and produce
high quality effluent. Homeowners should be encouraged (and potentially regulated) to prioritize
such maintenance as they would for other major investments (heating systems, vehicles, etc.).
Treatment performance of advanced onsite wastewater treatment systems
in the Otsego Lake watershed, 2008-20112
Holly Waterfield3
INTRODUCTION
This report serves to document the treatment performance of four advanced onsite
wastewater treatment systems monitored during the summers of 2008 through 2011. All four
systems are installed in the Otsego Lake watershed; three were installed as part of a NYS DEC
grant to demonstrate the use of advanced onsite wastewater treatment systems. Three systems
have been monitored since 2008 (Waterfield and Kessler 2009, Waterfield 2010, Waterfield
2011); OWTS 1 and OWTS 2, funded by the grant, and the UIC system (serving BFS Upland
Interpretive Center). Another system, also funded by the grant, was installed in the spring of
2009 at the BFS Thayer Farm. This system serves three buildings; the Hop House, Boat House,
and a rented residence. Due to operation and maintenance issues, OWTS 2 was not monitored in
2010 or 2011. Treatment performance was assessed based on the following analyses:
biochemical oxygen demand (BOD or CBOD), total suspended solids (TSS), nitrate (NO3),
ammonium (NH4), and total phosphorus (TP).
Otsego Lake is located in northern Otsego County, New York. According to the
historical overview by Harman, et al. (1997), the monitoring of Otsego Lake’s water quality
dates back to a 1935 NYS Department of Environmental Conservation (DEC) study. Routine
water quality monitoring efforts began subsequent to the establishment of the Biological Field
Station (BFS) in 1968 (Harman, et al. 1997). Comparisons to these and other historical datasets
had shown overall decreasing water quality conditions, noting in particular increased
phosphorous concentrations likely tied to loading from watershed activities (agriculture, road
maintenance, onsite wastewater treatment, etc.). Onsite wastewater treatment (septic) systems
are estimated to contribute only 7% of the total phosphorus load (Albright 1996), though the
combination of the bio-available form and time of greatest loading at the height of the growing
season is likely to lead to stimulation of algal production (Harman, et al. 1997). The cascading
effects of such nutrient loading on the lake’s ecosystem are far-reaching, and began to concern
lake users and the Village of Cooperstown, which uses Otsego Lake as its source of drinking
water. In 1985, the Village implemented public Health Law 1100 in order to give them legal
grounds to protect the lake as their source of drinking water (Harman, et al. 1997). Additional
actions to curb further water quality degradation in the lake culminated in the formation of a
watershed management plan in 1998, which identified nutrient loading as the greatest threat to
the health of Otsego Lake. Wastewater treatment via onsite treatment systems were listed
second on a prioritized list of action areas (Anonymous 1998), and efforts to manage the
effectiveness of these treatment systems began with a 2004 inventory of all systems in the
established Lake Shore Protection District followed by the inception of the inspection program in
2005 (Anonymous 2007). Under the program, any system found to be in failing condition is to
be replaced within one calendar year. Such replacement systems generally make use of
advanced or enhanced treatment technologies due to conditions that constrain the use of
2 Funding provided by NYSDEC grant #49298.
3 Research Support Specialist, SUNY Oneonta Biological Field Station.
- 1 -
conventional designs, such as setback to the lake or a tributary, soil depth to bedrock or
groundwater, percolation rate, etc. Many of these enhanced treatment technologies are new the
region, and thus are unfamiliar to industry professionals, regulators, and residents. For this
reason, a DEC grant was sought and obtained to fund a demonstration project to install and
monitor the treatment performance of six shared advanced treatment systems. The scope of the
grant has since been amended, changing the total number of treatment systems to three, with the
last installed in December of 2008.
Biochemical oxygen demand (BOD or CBOD) and total suspended solids (TSS) are
typical metrics used to characterize the strength of residential wastewater (Crites and
Tchobanoglous 1998). BOD is an analysis used to determine the relative oxygen requirements
of wastewater, effluents, and polluted waters, by measuring the oxygen utilized during a given
incubation period (APHA 1992). It is expected that organic material is broken down as
wastewater progresses through a treatment system, thus decreasing the oxygen requirements of
highly-treated wastewater and in turn resulting in lower BOD concentrations over the course of
the treatment system (APHA 1992). TSS analysis measures the total amount of suspended or
dissolved solids in wastewater. Solids may negatively affect water quality for drinking or bathing
and potentially clog a drain field. As with BOD, the amount of solids in treated effluent should
be lower than that of raw wastewater (APHA 1992).
Nitrate and ammonia concentrations will provide insight into the physio-chemical
conditions along the treatment train, as the transformations between various nitrogen forms are
dependent on oxygen availability, alkalinity, temperature, and the presence of specific bacterial
populations. Nitrogen is a dynamic component of wastewater treatment systems, which are often
designed to facilitate specific transformations of nitrogen species. Advanced treatment systems
most often incorporate a secondary treatment step that involves aerating the wastewater in order
to create favorable conditions for the bacterial transformation of ammonia to nitrate, called
nitrification. Nitrogen can be completely removed from the waste stream through the process of
denitrification, during which nitrate is converted to nitrogen gas (N2), which is released to the
atmosphere. Nitrification is generally considered the most limiting step of this overall nitrogen
removal process, as it supplies the nitrate that is converted to N2 gas.
Phosphorus, as previously mentioned, is the nutrient of greatest concern with regards to
vulnerable freshwater bodies. The removal of phosphorus from the waste stream prior to
subsurface disposal will be of great benefit to lake management efforts should the technologies
installed prove to be successful. The nutrient removal units installed in all four systems are of the
same, or very similar design, sourced from a single manufacturer. Phosphorus removal occurs
via adsorption of P onto active sites of an iron-oxide based reactive media; this design results in
the gradual reduction in performance as active adsorption sites on the media surface become
occupied. Eventually the adsorption capacity of the media is exhausted and the media must be
replaced in order to restore the treatment unit’s ability to effectively reduce the phosphorus
concentration leaving the treatment system.
- 2 -
METHODS AND MATERIALS
Four onsite wastewater treatment systems (OWTS) were monitored in this study and are
illustrated and described in Figure 1; these include the systems serving the SUNY Oneonta BFS
Thayer Farm Upland Interpretive Center (UIC) and Hop House (HH) and two shared homeowner
systems, OWTS 1 and 2. The UIC system has relatively high treatment capacity, as the UIC was
built to accommodate large groups for field trips and meetings. However, typical water usage is
relatively low due to the short duration of most events (<4 hours); actual flow has not been
measured. The system was installed and use commenced in fall of 2005. The system has been in
continuous operation, though initially the main tank was not sealed adequately and as a result
proper function did not begin until fall of 2007. Use of this facility increased during the summers
of 2009 and 2010, when typical BFS operations were moved temporarily to the Thayer Farm. A
period of intensive use occurred in 2011 and is reflected in the performance results. OWTS1 and
OWTS2 are located within 100 feet of the western shore of Otsego Lake off of State Highway
80, and are used mainly on weekends during the summer. Each system is shared by two adjacent
residences and they are designed to receive daily flows of 440 gallons and 550 gallons
respectively. Actual flow for OWTS1 was not measured. Flow through OWTS2 was measured
by the service provider. OWTS1 has been in use since 1 June 2006. OWTS2 has been in use
since 1 June 2007; this system was not monitored in 2010 or 2011 due to operational issues,
which have since been resolved. The HH system was installed at the BFS Thayer Farm to serve
the Hop House (BFS temporary main offices and labs), the Thayer Boat House, and the Thayer
Farm House (a residential rental) and operation began in April 2009 with waste from the Hop
House and Farm House. Flow from the Boat House began in August 2009. The system receives
consistent domestic flow from the Farm House, which is anticipated to be beneficial to the
treatment system especially during the winter months, which is a low-occupancy period at the
BFS.
Preliminary sampling efforts were conducted during the summer of 2007 in order to
assess the concentrations of various chemical and nutrient parameters. Regular grab samples
were collected between May and August 2008, and June through September 2009. Weekly
samples were collected between 9 June and 13 August 2010 and 6 June and 3 August 2011.
During each sampling event, approximately 600 mL of wastewater were collected following
each treatment component of all systems. Each sample site is shown in Figure 1 as “S#”.
Samples were tested for BOD5 using methods summarized by Green (2004). This method
involves determining initial dissolved oxygen (DO) concentration of the sample and nutrient
buffer followed by incubation at 20°C for five days and determination of the final DO
concentration. Samples were diluted to obtain target DO values such that the 5-day DO
concentration would be lower than the initial by at least 2 mg/L but with a final concentration
greater than 1 mg/L. These conditions were not always achieved, thus valid BOD values were
not obtained for every sample collected. Because a nitrification inhibitor is used during
incubation, results are presented as values of CBOD, and are associated with the carbonaceous
oxygen demand rather than the total oxygen demand (APHA 1992). Overall CBOD reduction
rates for each secondary treatment unit (OWTS 1, 2 and HH filters, UIC 1-3) were calculated
based on the average CBOD concentrations observed over the monitoring period, presented in
Table 6.
- 3 -
Figure 1. Onsite wastewater treatment system configurations. “S#” indicates a sampling point.
A) The UIC system is comprised of a 2-compartment tank, a phosphorus removal unit, a pump tank, and gravel bed drainfield.
Wastewater is circulated and aerated in the first chamber (UIC1 and 2), and settles in the clarification chamber for final solids
settling (UIC3). It then flows through the phosphorus removal unit, on to a pump chamber (UIC4), from which it is pumped in to
the drain field.
B) OWTS1 provides primary treatment in a septic tank and processing tank (PTE) which flow into an equalization tank, then to a
pump tank where the wastewater is pumped and sprayed over an open-cell foam media filter (BFE). In this case the foam media
filter aerates the wastewater and provides surface area for beneficial bacteria, increasing organic digestion. 25% of flow is
returned to the headworks of the processing tank to facilitate the removal of nitrogen from the waste stream, and 50% flows to
the P removal unit (PRE) and on to the drainfield via gravity.
C) OWTS2 provides primary treatment in 2 septic tanks which flow to a two-compartment processing tank. Effluent flows from
the processing tank to a pump tank which periodically doses a textile media filter. Filter-effluent (AXE) is split between the
processing tank (PTE) and the P removal unit (PRE). A portion of effluent from the textile media filter is returned to the
processing tank to facilitate the removal of nitrogen from the waste stream.
D) HH provides primary treatment in 2 septic tanks (STE) which flow to a two-compartment processing tank (PTE). Effluent is
pumped from the processing tank to a textile media filter. Filter-effluent (AXE) is split between the processing tank (PTE) and
the P removal unit (PRE). A portion of effluent from the textile media filter is returned to the processing tank to facilitate the
removal of nitrogen from the waste stream.
- 4 -
Total suspended solids (TSS) concentration was determined according to the standard
method (APHA 1992). A recorded volume of wastewater was filtered through a rinsed, dried,
pre-weighed glass fiber filter. Filters were dried for a minimum of 24 hours at 105°C in a
gravimetric oven and then removed to a desiccator to cool before being weighed. The
concentration of solids in each sample was calculated from the weight of the filtered solids and
the volume of sample filtered; concentrations are reported in mg solids/L. Overall TSS reduction
rates for each secondary treatment unit (OWTS 1, 2 and HH filters, UIC 1-3) were calculated
based on the average TSS concentrations observed over the monitoring period, presented in
Table 6.
Total phosphorus concentrations were determined using the ascorbic acid following
persulfate digestion method run on a Lachat QuikChem FIA+ Water Analyzer (Laio and Marten
2001). Nitrate and ammonia concentrations were also determined for most samples, using
Lachat-approved methods (Pritzlaff 2003, Liao 2001). All reduction and transformation rate
estimates are calculated based on average concentrations observed over the duration of the
monitoring period (Table 6). Total nitrogen concentrations were not determined and are not
presented here due to incomplete oxidation of ammonia to nitrate during the digestion process,
which results in underestimation of TN concentration.
SYSTEM PERFORMANCE, OPERATION, AND MAINTENTANCE
Monitoring results for each sampling location in all treatment systems are presented in
tabular and graphical form for all parameters monitored (Tables 1-6, Figures 2-5). The tables
summarize the testing results for each year (2008-2011) and over the entire monitoring period,
including calculated standard error and the sample size. Figures for CBOD, TSS, TP and
NO3/NH4 include standard error bars. The overall performance of the systems can be assessed by
comparing the first stage of treatment with the last. Typical CBOD concentrations associated
with raw wastewater vary greatly (100 – 600 mg/L) depending on per capita water usage and
inputs of solids to the system (i.e. garbage grinder waste) (Crites and Tchobanoglous 1998). The
industry standard for BOD5 and TSS in effluent from secondary treatment units is 30 mg/L (NSF
2007).
Each system will be discussed individually in the following sections; the treatment
performance of each is assessed in addition to a description of operation and maintenance issues
encountered over the course of the monitoring period. At the time of installation and design,
phosphorus removal units were available from single manufacturer, and so the same treatment
unit is used in all four systems; the results obtained for each treatment system expose the same
performance and maintenance issues for this specific treatment unit, which are addressed in the
last section, Phosphorus Removal Components.
- 5 -
average +\- SE n average +\- SE n average +\- SE n average +\- SE n average +\- SE n
UIC1 12 1.62 10 22 7.45 6 15 2.03 9 66 38.05 5 24 6.45 31
UIC2 10 1.06 11 8 2.82 5 12 1.37 9 54 29.07 6 19 5.86 31
UIC3 8 0.93 10 9 2.57 4 11 0.97 9 54 28.11 6 19 6.06 29
UIC4 12 1.54 9 28 - - 1 - - - - - - - - - - 14 2.10 10
OWTS1 PTE 93 16.47 11 110 21.75 5 92 12.94 9 43 8.78 5 86 8.44 30
OWTS1 BFE 62 14.64 8 45 9.53 6 26 2.76 9 37 7.45 5 43 5.31 28
OWTS1 PRE 28 3.53 7 25 10.41 3 - - - - - - - - - - 27 3.65 10
OWTS2 PTE 255 64.90 6 238 19.25 5 - - - - - - - - - - 247 34.98 11
OWTS2 AXE 16 3.99 4 57 20.96 6 - - - - - - - - - - 41 13.91 10
OWTS2 PRE 12 1.78 5 7 5.67 2 - - - - - - - - - - 11 2.02 7
HH STE - - - - - 186 22.55 5 229 12.64 9 126 25.15 7 178 13.84 21
HH PTE - - - - - 22 6.14 5 23 2.58 9 6 1.10 3 18 2.68 17
HH AXE - - - - - 6 2.69 6 2 0.47 8 1 0.00 7 3 0.85 21
HH PRE - - - - - 3 1.85 2 - - - - - - 1 0.00 2 2 0.93 4
Table 1. Average carbonaceous biochemical oxygen demand (CBOD)in mg/L determined for onsite
wastewater treatment systems between 2008 and 2011, with calculated standard error (SE), sample size (n) for
2008 through 2011 and over the entire monitoring period.
Carbonaceous Biochemical Oxygen Demand
Site2008 2009 2010 2011 overall
Figure 2. Average 2008-2011 carbonaceous biochemical oxygen demand (CBOD) in mg/L determined for
onsite wastewater treatments systems. Bars indicate standard error.
0
50
100
150
200
250
300
UIC OWTS1 OWTS2 HH
CB
OD
(m
g/L
)
Site
Carbonaceous Biochemical Oxygen Demand
- 6 -
average +\- SE n average +\- SE n average +\- SE n average +\- SE n average +\- SE n
UIC1 18.7 3.35 4 - - - - - 21.4 4.59 8 28.2 10.15 6 22.8 3.60 18
UIC2 58.3 42.82 4 - - - - - 12.8 2.14 8 33.0 12.15 6 31.1 10.38 18
UIC3 39.2 29.28 4 - - - - - 11.2 1.67 8 21.8 4.57 6 21.9 6.67 18
UIC4 5.3 2.15 4 - - - - - - - - - - - - - - - - - - - -
OWTS1 PTE 116.4 73.00 4 - - - - - 82.9 11.45 8 42.1 15.88 5 77.6 17.86 17
OWTS1 BFE 46.3 11.35 4 - - - - - 32.1 1.89 8 23.6 3.10 5 33.7 4.09 17
OWTS1 PRE 13.1 5.89 4 - - - - - - - - - - - - - - - - - - - -
OWTS2 PTE 75.1 23.21 4 - - - - - - - - - - - - - - - 67.9 8.93 17
OWTS2 AXE 5.1 1.96 4 - - - - - - - - - - - - - - - 24.0 3.88 17
OWTS2 PRE 7.1 2.06 4 - - - - - - - - - - - - - - - - - - - -
HH STE - - - - - - - - - - 57.1 4.97 8 34.6 3.74 7 46.6 3.98 15
HH PTE - - - - - - - - - - 18.5 2.30 8 5.8 1.12 7 11.5 1.99 15
HH AXE - - - - - - - - - - 2.7 0.72 8 1.8 0.36 7 2.6 0.54 15
HH PRE - - - - - - - - - - - - - - - - - - - - - - - - -
Table 2. Average total suspended solids (TSS)in mg/L determined for onsite wastewater treatment systems
between 2008 and 2011, with calculated standard error (SE), sample size (n) for 2008 through 2011 and over
the entire monitoring period.
Total Suspended Solids
Site2008 2009 2010 2011 overall
Figure 3. Average 2008-2011 total suspended solids (TSS) in mg/L determined for onsite wastewater
treatments systems. Bars indicate standard error.
0
20
40
60
80
100
UIC OWTS1 OWTS2 HH
To
tal
Susp
end
ed S
oli
ds
(mg/L
)
Site
Total Suspended Solids
- 7 -
average +\- SE n average +\- SE n average +\- SE n average +\- SE n average +\- SE n
UIC1 57.82 2.48 13 43.81 6.30 6 61.73 1.90 5 36.03 10.24 6 51.31 3.07 30
UIC2 59.29 2.33 13 38.81 6.86 6 62.06 1.97 5 31.74 9.49 6 50.14 3.33 30
UIC3 60.51 4.04 13 38.44 6.61 6 61.04 1.74 5 36.00 8.25 6 51.28 3.38 30
UIC4 25.54 0.95 13 35.13 5.50 6 30.20 - - 1 24.11 7.21 5 27.74 2.06 25
OWTS1 PTE 2.39 1.53 7 22.46 1.14 4 37.92 11.76 5 42.50 10.74 5 20.34 5.51 21
OWTS1 BFE 31.95 3.95 15 54.28 10.37 6 80.30 7.37 5 59.40 2.76 5 48.50 4.34 31
OWTS1 PRE 32.19 5.45 13 32.31 4.71 6 40.60 - - 1 19.90 16.55 3 30.99 3.74 23
OWTS2 PTE 0.05 0.01 6 0.46 0.16 6 - - - - - - - - - - - - 11.33 5.35 17
OWTS2 AXE 29.54 6.38 6 24.63 8.83 5 - - - - - - - - - - - - 43.87 7.52 16
OWTS2 PRE 22.78 4.88 7 7.52 1.35 6 - - - - - - - - - - - - 17.51 3.62 14
HH STE - - - - - - 0.15 0.04 5 - - - - - - - - - - - - 0.15 0.04 5
HH PTE - - - - - - 32.82 5.36 6 42.00 4.21 5 45.83 4.17 7 40.43 2.86 18
HH AXE - - - - - - 39.17 3.51 6 50.25 1.58 5 44.81 3.49 7 44.44 2.04 18
HH PRE - - - - - - 39.97 3.61 5 55.00 - - 1 46.08 3.19 6 44.28 2.45 12
Table 4. Average ammonium (NH4)in mg/L determined for onsite wastewater treatment systems between 2008
and 2011, with calculated standard error (SE), sample size (n) for 2008 through 2011 and over the entire
monitoring period.
Table 3. Average nitrate concentration in mg/L determined for onsite wastewater treatment systems between
2008 and 2011, with calculated standard error (SE), sample size (n) for 2008 through 2011 and over the entire
monitoring period.
2009 2010 2011 overallSample
2008
Nitrate
Sample 2008 2009 2010 2011 overall
average +\- SE n average +\- SE n average +\- SE n average +\- SE n average +\- SE n
UIC1 1.70 0.75 7 1.05 0.44 5 0.71 0.33 5 45.31 18.14 5 11.24 5.53 22
UIC2 1.59 0.71 6 0.97 0.49 5 0.77 0.38 5 52.31 16.21 6 15.10 6.47 22
UIC3 1.36 0.74 7 1.02 0.55 5 0.64 0.35 5 49.68 15.38 6 13.73 5.90 23
UIC4 3.02 0.78 10 8.53 4.14 4 0.09 0.04 4 44.85 17.27 5 12.56 5.08 23
OWTS1 PTE 87.71 5.79 15 73.47 6.10 6 88.90 2.51 5 62.10 4.42 5 81.02 3.56 31
OWTS1 BFE 46.34 3.91 15 46.16 4.40 6 39.74 2.61 5 44.20 4.85 5 44.90 2.22 31
OWTS1 PRE 42.44 2.89 13 26.87 7.00 6 20.20 3.18 4 51.13 4.10 4 36.97 2.93 27
OWTS2 PTE 85.43 2.60 9 63.27 7.03 6 - - - - - - - - - - - - 76.48 3.44 23
OWTS2 AXE 23.35 8.66 7 50.44 9.74 6 - - - - - - - - - - - - 37.15 4.56 21
OWTS2 PRE 26.93 7.95 7 24.53 4.20 6 - - - - - - - - - - - - 26.80 3.58 19
HH STE - - - - - - 63.99 9.96 5 78.20 2.47 5 63.56 10.49 7 67.99 5.24 17
HH PTE - - - - - - 16.12 2.08 6 18.30 4.30 5 10.09 2.86 7 14.38 1.87 18
HH AXE - - - - - - 3.00 1.79 3 0.87 0.38 4 0.04 0.02 7 0.91 0.46 14
HH PRE - - - - - - 0.24 0.06 2 1.68 0.30 4 0.04 0.02 7 0.58 0.23 13
monitoring period.
Ammonium
- 8 -
Figure 4. Average 2008-2011 nitrate and ammonium concentrations in mg/L determined for onsite
wastewater treatments systems. Bars indicate standard error.
0
20
40
60
80
100
120
UIC OWTS1 OWTS2 HH
Co
nce
ntr
atio
n m
g N
/L
Site
Ammonia (mg/L)
Nitrate (mg/L)
- 9 -
average +\- SE n average +\- SE n average +\- SE n average +\- SE n average +\- SE n
UIC1 7.03 0.66 12 10.18 1.49 6 9.1875 1.14 8 11.4183 0.855 6 8.98475 0.558 32
UIC2 6.60 0.37 12 9.98 1.57 6 9.08625 1 8 11.6283 0.881 6 8.79827 0.537 32
UIC3 6.34 0.32 12 10.64 1.91 6 9.4525 1.03 8 11.2417 0.846 6 8.84218 0.582 32
UIC4 0.66 0.09 12 5.25 1.37 6 3.555 1.08 8 5.062 0.915 5 3.00343 0.527 31
OWTS1 PTE 11.70 0.69 13 15.96 1.99 6 14.3457 1.37 7 11.56 0.621 5 13.1008 0.637 31
OWTS1 BFE 12.57 0.85 13 18.80 1.69 6 17.6014 2.09 7 15.96 2.089 5 15.4614 0.854 31
OWTS1 PRE 9.77 0.60 11 0.89 0.14 6 2.91125 1.18 6 2.36 0.44 3 5.2837 0.859 26
OWTS2 PTE 9.55 0.22 8 11.64 1.96 6 - - - - - - - - - - 11.7445 0.821 21
OWTS2 AXE 9.07 0.44 5 12.73 1.81 6 - - - - - - - - - - 13.6071 1.285 18
OWTS2 PRE 6.71 0.90 6 0.61 0.23 6 - - - - - - - - - - 3.4106 0.77 18
HH STE - - - - - 9.42 1.53 4 11.17 1.09 8 10.14 0.62 7 10.42 0.59 19
HH PTE - - - - - 8.95 1.80 5 10.25 1.40 8 8.33 0.35 7 9.25 0.71 20
HH AXE - - - - - 11.51 2.06 5 10.99 1.47 8 7.45 0.45 7 9.88 0.86 20
HH PRE - - - - - 7.86 1.79 5 11.74 1.34 8 7.51 0.48 6 9.38 0.85 19
Table 5. Average total phosphorus concenration (TP)in mg/L determined for onsite wastewater treatment
systems between 2008 and 2011, with calculated standard error (SE), sample size (n) for 2008 through
2011 and over the entire monitoring period.
Total Phosphorus
Site2008 2009 2010 2011 overall
Figure 5. Average 2008-2011 total phosphorus (TP) in mg/L determined for onsite wastewater treatments
systems. Bars indicate standard error.
0
2
4
6
8
10
12
14
16
18
UIC OWTS1 OWTS2 HH
To
tal
Pho
spho
rus
(mg/L
)
Site
Total Phosphorus
- 10 -
N Removal
% n % n % n % n %
UIC 22 31/29 4 18 66 32/31 -0.6 22/25 37
2008 40 10/9 91 4 90 12 0.5 7 52
2009 57 6/5 - - - - 51 6 80 5/4 2
2010 27 10 48 8 62 8 1 5/4 51
2011 19 5/6 23 6 55 6/5 1 5/4 15
OWTS 1 50 30/28 57 17 66 31/26 54 31 33
2008 34 11/8 60 4 22 13/11 47 15 13
2009 59 5/6 - - - - 95 6 63 6 36
2010 72 10 61 8 83 7 77 5 52
2011 14 5 44 5 85 5/3 18 6 32
OWTS 2 84 11/10 65 17 75 18 65 23/21 50
2008 94 6/4 93 4 26 5/6 74 9/7 42
2009 76 5/6 - - - - 95 6 61 6 50
2010 - - - - - - - - - - - - - - - - - -
2011 - - - - - - - - - - - - - - - - - -
HH 99 21 94 15 5 20/19 99 17/14 34
2008 - - - - - - - - - - - - - - - - - -
2009 97 5/6 - - - - 32 5 99 5/3 37
2010 99 9 95 8 -7 8 98 5/3 35
Table 6. Average rates of removal or reduction for CBOD, TSS, TP, NH4, and Nitrogen calculated for each
onsite wastewater treatment system overall and for each year 2008 through 2011, with sample size (n).
TP NH4 DecreaseSystem
CBOD TSS
2010 99 9 95 8 -7 8 98 5/3 35
2011 99 7 95 7 -1 7/6 99 5/3 29
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Upland Interpretive Center (UIC) Typical flow through the system was greatly below the design flow capacity for the
majority of the monitoring period; throughout the monitoring period the system produced high
quality effluent, meeting the NSF Standard 40 for Class 1 ATUs (30mg/L CBOD and TSS). In
2010 the system saw more consistent usage and monitoring results indicate enhanced reduction
of CBOD and TSS, with high quality effluent produced (final CBOD < 11 mg/L, TSS = 11
mg/L). In 2011, the system experienced a period of intense use, which may have been beyond
the treatment capacity of the system. Though this period was relatively short in comparison to
the monitoring period (10 days of use by 19 individuals), average 2011 effluent CBOD and TSS
concentrations increased substantially, to 54 mg/L and 22 mg/L, respectively (Tables 1 and 2).
Over the 4-year monitoring period, the system proved to handle long periods of low usage well.
The size of the system is able to accommodate sporadic short-duration heavy-use events without
noticeable influence on the quality of final effluent.
Though nitrogen reduction is not a priority of treatment in the Otsego Lake watershed’s
wastewater management program, the nitrogen transformations that take place in advanced
treatment systems are notable and give insight into the conditions within the treatment system.
The final effluent from the UIC system contains relatively high nitrate to ammonium ratio,
indicating that the aeration provided in the unit is sufficient for nitrification to take place.
System-wide over the 4-year period, nitrogen was reduced by 37%; better removal rates occurred
during years where use of the system was higher (without exceeding the design-capacity) (Table
6).
Operational Notes
The only major issue encountered with the UIC system was related to its installation.
The mid-seam of the 3-compartment tank was not properly sealed at the time of installation. For
the first season of its use, the full operating level was never attained (i.e. the tank remained
approximately half-full). The problem was not immediately diagnosed because of the low use of
the system during non-summer months. Following repair the system has maintained an
appropriate operating level.
The blower/aerator by design runs full-time (24/7) and has had no mechanical problems
to date. The microbiological inoculant must be replaced on occasion; this doesn’t seem to be
critical in the overall functionality of the system. As with all four monitored systems, the
nutrient removal unit’s reactive media must be replaced regularly to maintain high phosphorus
removal rates and sufficiently low final P concentrations. This is likely more important for units
serving systems in close proximity to P-limited water bodies.
Onsite Wastewater Treatment System 1 (OWTS 1)
The configuration of this system seems to be less robust than others for seasonal-use
situations, due in large part to the above-ground installation of the media filter combined with
summer-only use and the long start-up time for the microbiological community that lives in and
on the foam media. The foam media comprising the filter in this system is susceptible to settling
over time, especially during periods of freeze and thaw. This particular system is installed above
ground, and therefore is subjected more extreme temperature variation than its below-ground
counterparts. Extreme temperature fluctuations and long period of dormancy (without nutrient,
carbon, and water supply) also influence the microbial community, contributing to the long
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period of time required for treatment performance to reach a consistent level following dormant
periods. Treatment performance of this particular installation did not meet the manufacturer’s
expectation (Jowett 2010) nor was it consistent with the results of other field testing studies
(ETV 2003, MASSTC 2004). This discrepancy is likely due to the difference in both
configuration and actual use of the system.
Treatment of BOD and TSS improved steadily over the duration of the monitoring
program and treatment proved to be enhanced by spring maintenance to combat settling of the
foam media that may have occurred during the winter. BOD and TSS concentrations averaged
43 and 33 mg/L, respectively, following treatment in the foam filter. This does not meet the
industry standard of 30 mg/L for each parameter (for secondary treatment performance as Class
1 Aerobic Treatment Unit, media filter, etc), though the system was likely still in the “start-up”
phase for the majority of the monitoring period each summer. Monitoring protocols used in this
study are also different than those used by the National Sanitation Foundation when testing
advanced treatment systems again performance criteria (NSF 2007).
Nitrogen concentrations were in line with the other systems monitored, though the
incoming ammonium concentration was generally greater than the other systems. This is likely
due to the fact that the system was being used on a regular basis and with water conservation in
mind, producing a more concentrated waste. Over the entire monitoring period, nitrogen
removal averaged about 33%. The reduction of ammonium concentration before and after
treatment by the foam filter unit (54%) was less than that achieved by the other systems; this
indicates a less effective conversion of ammonium to nitrate within the foam filter itself.
Following a service visit in early 2010, the ammonium reduction rate increased (to 77%),
indicating that the environment within the filter was better suited to facilitate the nitrification
process.
Operational Notes
Operation and maintenance issues were related to settling of the foam media over time.
Spring maintenance was effective at restoring the treatment performance for all parameters. This
servicing involved redistribution of the foam to restore the original packing density and eliminate
any preferential flow paths that had allowed wastewater to short-circuit the media. Ideally,
wastewater should trickle in a thin film through and around the foam cubes.
Odor coming from this system was also a major issue for the property owners, though it
was a design flaw that did not directly impact the treatment performance and was independent of
the manufacturers of the treatment components. Three sources of odor were identified; one was
the system’s vent stack, another was the lid of the equalization tank, which receives processing
tank effluent (mix of septic tank of effluent and foam filter effluent), and the third was the
electrical conduit connecting the pump vault to the control panel. All three sources were
remedied, though these should be considered by the design engineer prior to installation. The
vent stack was extended above the roof-line in order to physically move it away from the patio
and deck areas of the two camps served by the system. This pipe was also capped with a carbon-
filter assembly to reduce the final odor. The equalization tank’s cover is of poor design and does
not provide an air-tight or water-tight seal at the surface. The odor was greatly reduced by
weighting the lid down; ideally, this lid should be replaced with a model that will provide a more
secure seal. The conduit from the pump vault to the control panel was left unsealed by the
installer, and so proved to be the preferential flow path for gas exchange. This conduit was
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sealed with a caulking agent, eliminating the odor problem. All-in-all, while the odor problem
did not directly affect treatment performance, public perception and acceptance of advanced
treatment systems can be negatively impacted by such oversights.
Onsite Wastewater Treatment System 2 (OWTS 2)
Overall treatment performance met expectations in 2008 and most of the 2009 monitoring
period compared to the performance of other systems of this type. Prior to the operational
problems that began in 2009, OWTS 2 produced high quality effluent containing less than 15
mg/L BOD and TSS on average (Tables 1 and 2) with nitrogen removal between 42 and 50%
(Table 6). As a result of the operational issues and subsequent maintenance that was required
this system was not monitored in 2010 or 2011.
Operational Notes
This system experienced periods of poor treatment unrelated to the design or the
treatment processes employed in the system. One of the camps served by the system underwent
major renovations, during which time electrical power to the system was inadvertently shut off;
this system does not operate by gravity-flow, and so relies on timers, switches, and pumps for
proper cycling of wastewater between the treatment components. Although no one was living in
the renovated camp, the other camp served by the system was still occupied and sending
wastewater to the system. Wastewater was not treated properly and resulted in fouling of the
nutrient removal device. The problem persisted though 2011 due to lack of communication
between the main service provider to the system and the homeowner, as well as between the
main service provider and the manufacturer/service provider for the nutrient removal unit.
This issue highlights a number of areas where more work is needed to ensure that
advanced treatment systems are operating properly and to the best of their ability; (1) the need
for effective communication between involved parties (regulators, homeowners, and service
providers) to ensure that maintenance contracts are in place and carried out according to the
manufacturer’s guideline (2) the challenges associated with effectively operating a shared system
and (3) the need for homeowners to be aware of the system’s function and operation. All users
of the structure must be aware of “good practices” for disposal of wastes in the system – this
includes tenants, contractors, guests, etc. These systems are highly engineered and treatment
often relies on the presence of beneficial microbial communities. Disposal of chemicals, paints,
disinfectants, etc. can reduce or eliminate the populations of such microbes and may also cause
fouling of or reduced longevity of other physical and mechanical components of the system (e.g.
textile fabrics, coarse filters, pumps, etc.).
Hop House (HH) Treatment performance has consistently been at a high level and no major maintenance
issues have occurred to date aside from the high media replacement rate for the nutrient removal
unit. Incoming waste was of typical strength (100-600 mg/L) for American households. CBOD
and TSS concentrations averaged 3 mg/L following treatment in the textile filter (Tables 1 and
2); this is an exceptional level of treatment and standard error indicates a low degree of
variability with respect to fluctuations in the concentration of these two parameters. Ammonium
concentration was reduced to less than 1 mg/L on average (Table 4), a 99% reduction from the
septic tank effluent to textile filter effluent. Nitrogen removal averaged around 34%, which is
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lower than seen in OWTS 2, and may be enhanced by altering the system dosing cycles based on
the actual flow received; this is discussed further in the Operational Notes.
Operational Notes
No major treatment or mechanical issues were encountered during the monitoring period;
all pumps and controls are functioning properly. This particular system has a larger design
capacity than a typical residential situation (the Hop House and Boat House are served in
addition to a residence); however, the actual flow through the system has generally been less
than anticipated. Actual flow through the system can be calculated, but to date this information
has not been used to adjust the rate at which wastewater is cycled from the processing tank to the
textile filter. As a result, the textile filter is dosed more often than is necessary to adequately
treat the waste and therefore the processing tank does not consistently maintain an anaerobic
environment to facilitate denitrification (final step of nitrogen removal) of effluent coming in
from the textile filter. Treatment would be enhanced by increased oversight of the system by the
service provider.
Phosphorus Removal Components
The nutrient removal devices are designed to remove phosphorus from the wastewater via
chemical adsorption of phosphorus onto the surface of a reactive porous media. Over time the
active sites are occupied by adsorbed phosphorus and the efficiency declines until no active sites
remain. These work well but require frequent replacement in order to maintain high degree of
phosphorus removal, as a result of the relatively small volume of reactive media in each unit.
Larger media canisters would reduce the frequency of media replacements. The size of each unit
was not scaled to correspond to the designed treatment capacity of the system with which it was
installed. In the case of the Hop House system, following replacement of the reactive media,
acceptable treatment was documented for less than 3 months before the adsorptive capacity of
the media was reached. Frequent sampling and analysis for total phosphorus concentration is the
only way to determine the efficacy of each unit; it is unlikely that such sampling would be done
more than once per year in a typical residential situation.
CONCLUSIONS
Treatment Technologies
Media Filters (Textile, Foam, Dosing Regime)
Textile filters provided the most consistent and effective treatment of the three types
installed in the demonstration systems. CBOD and TSS were consistently below 15 mg/L and
showed little variation over the sampling period under normal operating conditions. The filter
media are arranged in hanging sheets, and so are not subject to settling or compaction over time;
it seems that this arrangement, combined with an insulated cover and below-ground installation,
result in a short start-up period at the beginning of the occupancy season.
The foam filter’s performance was variable and frequently fluctuated above the industry
standard for this class of system. When installed for seasonal use, spring maintenance is needed
to ensure that the media is properly distributed in the baskets, as settling may have occurred due
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to freeze and thaw during the winter. A long period of time (upwards of 8 weeks in some cases)
was required at the start of each summer occupancy season for the establishment of a sufficient
microbial community such that consistent and acceptable treatment was documented. Microbial
populations are greatly reduced during periods without flow (i.e. winter) and are likely further
reduced during periods of extreme cold. This should be considered in the design process if this
technology is to be used at other seasonal installations; installing the media filter underground
may provide enough thermal buffering to reduce the temperature fluctuation and in so doing,
reduce the settling and start-up period.
Differences observed in the treatment performance of the foam and textile filters may be
related more to the dosing regimens rather than the ability of either media to provide a favorable
treatment environment. Dosing regimes are typically based on either time or demand (flow).
• A Timed Cycle: A predetermined volume is dosed at a regular time interval. Both
systems incorporating textile filters (OWTS 2 and HH) were time-dosed (a
requirement of the manufacturer).
o Storage capacity is built-in to allow for holding of wastewater for later
processing based on default schedule
o Flow is distributed over a 24-hour period
� Eliminates potential inundation of treatment components and the
drainfield;
• Holds water during high-use periods (shower-time, laundry,
etc.)
• Cycles wastewater throughout the day and night, providing
consistent flows to the treatment technologies and the
drainfield during lower-use periods
� Allows for alternation between unsaturated and saturated flow, and
thus, aerobic and anaerobic conditions
• Facilitates gas exchange
• Facilitates activity of both aerobic and anaerobic microbial
populations – together yield more effective and complete
breakdown of wastewater constituents
o Floats detect high-flow conditions and can trigger the over-ride of default
timing cycle to more quickly process wastewater, accommodating extreme
events without compromising the integrity of system components.
o In seasonal-use or weekend-use situations, cycling of wastewater between
a processing tank and the filter continues even during periods where no
new water enters the system, maintaining nutrient and water supply to the
microbial populations.
• Demand (flow through the system): A predetermined volume is transferred every
time that specific volume accumulates in a dosing chamber. The foam filter
(OWTS 1) operated on demand-dosing.
o During high flow periods, wastewater may be dosed without a time delay
in order to keep up with incoming flow. This may result in the inundation
of subsequent treatment components (such as a nutrient removal device)
that have a limited volume capacity and require a longer period of time for
wastewater to pass through.
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o During periods with little or no use, no water is dosed to the filter unit,
potentially resulting in a reduction in the microbial population.
.
Aerobic Treatment Unit
The aerobic treatment unit (ATU) serving the UIC produced effluent of consistent
quality, though the system saw very low use compared to its designed capacity. CBOD and TSS
were generally below 15 mg/L and nitrogen was removed at moderate rates. It handled typical
UIC functions and events (field trips, workshops, etc.) and long periods of low use very well
without compromising effluent quality.
Phosphorus Removal Devices
The effective life-span of the reactive media within the phosphorus removal devices was
disappointing, especially given the cost of the units and fees associated with media replacement.
These units work well but require frequent replacement in order to maintain high degree of
phosphorus removal as a result of the relatively small volume of reactive media in each unit.
Larger media canisters would reduce the frequency of media replacements. In order to
adequately address the need for phosphorus removal in certain locales, a more affordable,
longer-lasting design is essential.
Monitoring Procedures
Sampling protocols can influence the observed treatment performance and varies with the
type and configuration of each system. Comparisons between monitoring and assessment efforts
should acknowledge such details.
• Grab samples are likely to be more variable and have a higher associated
standard error if the quality of effluent is variable over the course of a day.
• Composite samples capture the range of conditions encountered throughout the
day, providing flow-weighted results of effluent quality produced by the system.
• The potential for sampling protocol to influence results will vary with the
configuration of the system.
o Some systems continuously mix wastewater and yield more consistent
results over the course of a 24-hour period, whereas a system with discrete
treatment components will experience variation over the course of a day,
depending on use of the system, in which case a grab sample may yield
non-representative results if such factors are not considered.
• Sufficient sample size should allow for a range of conditions to be encountered,
providing an average that is representative of the effluent quality that typically
leaves the system, though this cannot be guaranteed.
Lessons Learned
Oversight of Operation & Maintenance
Communications with service providers and manufacturers resulted in remedied issues
and increased treatment performance. Vigilance in the maintenance of advanced treatment
systems is of the utmost importance if these systems are to be relied upon to reduce human
- 17 -
impacts to sensitive environments, especially considering that the vast majority of systems are
not monitored once they are installed, as they were with this project.
Property Owner Awareness & Proper Use Homeowners, as the primary users of such systems, are the key to ensuring proper use
and maintenance. Steps should be taken to stress the importance of their participation as a means
of protecting their investment in addition to protecting public health and their surrounding
environment. In a few instances, as outlined in the system performance section of this report,
operational issues occurred due to a lack of communication between the property owners of
shared systems, or between the property owners and others that were renting or working on the
property. Owners failed to recognize the importance of informing the other users as to the
requirements of the system (i.e. electrical power) and best practices for disposal of materials to
the system.
REFERENCES
Albright, M.F. and H.A. Waterfield. 2010. Evaluation of phosphorus removal media for use in
onsite wastewater treatment. In: 42nd
Ann. Rept. (2009). SUNY Oneonta Bio. Fld. Sta.
Cooperstown, NY.
Albright, M.F., L.P. Sohaki, and W.N. Harman. 1996. Hydrological and nutrient budgets for
Otsego Lake, N.Y. and relationships between land form/use and export rates of its sub-
basins. Occ. Paper #29, SUNY Oneonta Bio. Fld. Sta., SUNY Oneonta.
Anonymous. 1998. A plan for the management of the Otsego Lake watershed. Prepared by:
Otsego Lake Watershed Council.
Anonymous. 2007. A plan for the management of the Otsego Lake watershed. Prepared by:
Otsego Lake Watershed Council (1998). Updated by the Otsego County Water Quality
Coordinating Committee.
APHA, AWWA, WPCF. 1992. Standard methods for the examination of water and wastewater,
17th
ed. American Public Health Association. Washington, DC.
Crites, R. and G. Tchobanoglous. 1998. Small and Decentralized Wastewater Management
Systems. McGraw-Hill, p183
Environmental Technology Verification Program (ETV). 2003. ETV Joint Verification
Statement: Waterloo Biofilter®
Model 4-Bedroom. National Sanitation Foundation and
US Environmental Protection Agency.
Green, L. 2004. Standard Operating Procedure 011: Biochemical Oxygen Demand (BOD)
Procedure. University of Rhode Island Watershed Watch.
Harman, W.N. 1997. The state of Otsego Lake 1936-1996. Occ. Paper #30, SUNY Oneonta Bio.
Fld. Sta., SUNY Oneonta.
- 18 -
Jowett, C. 2010. Personal Communication. February 2010.
Knight Treatment Systems. 2007. The knight nutrient removal device.
http://www.knighttreatmentsystems.com. Accessed March 2011.
Liao, N. 2001. Determination of ammonia by flow injection analysis. QuikChem®Method 10-
107-06-1-J. Lachat Instruments. Loveland, Colorado.
Liao, N. and S. Marten. 2001. Determination of total phosphorus by flow injection analysis
(colorimetry acid persulfate digestion method). QuikChem®Method 10-115-01-1-F.
Lachat Instruments. Loveland, Colorado.
MASSTC. 2004. US EPA Environmental Technology Initiative Onsite Wastewater Technology
Testing Report: Waterloo Biofilter®. Massachusetts Alternative Septic System Test
Center, Cape Cod, MA.
National Science Foundation (NSF). 2007. NSF wastewater programs update and NSF/ANSI
standards 40 and 245. (presentation). www.nsf.org
Pritzlaff, D. 2003. Determination of nitrate/nitrite in surface and wastewaters by flow injection
analysis.QuikChem®Method 10-107-04-1-C. Lachat Instruments, Loveland, Colorado.
Waterfield, H.A. 2010. Treatment performance of advanced onsite wastewater treatment systems
in the Otsego Lake watershed, 2009 results update. In: 42nd
Ann. Rept. SUNY Oneonta
Bio. Fld. Sta. Cooperstown, NY.
Waterfield, H.A. 2011. Treatment performance of advanced onsite wastewater treatment systems
in the Otsego Lake watershed, 2010 results update. In: 43rd
Ann. Rept. SUNY Oneonta
Bio. Fld. Sta. Cooperstown, NY.
Waterfield, H.A. and S. Kessler. 2009. Treatment performance of advanced onsite wastewater
treatment systems in the Otsego Lake watershed, 2008 results. In: 41st Ann. Rept. SUNY
Oneonta Bio. Fld. Sta. Cooperstown, NY.
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