Task 3: Fabrication and installation of the MUS system.
Monitoring and injection wells will be installed by hydraulic
jetting. Two injection wells will be installed. One well will
serve as a backup in case of catastrophic failure of the main
well. The wells will be constructed of schedule 40 PVC, with
a _" diameter pipe surrounded by a 2" diameter casing.
Well screen will be utilized on the monitoring wells to prevent
clogging and facilitate sample collection.
Task 4: Determination of influent wastewater characteristics.
Monthly samples will be drawn from the main holding tank
to develop a database of raw wastewater characteristics. Parameters
investigated will include: fecal coliforms, E. coli,
temperature, pH, dissolved oxygen, total suspended solids (TSS),
volatile suspended solids (VSS), BOD5, total kjeldahl
nitrogen (TKN), total ammonia nitrogen (TAN), nitrate, total
phosphorus, orthophosphorus, and particle size distribution.
Following collection, samples will be placed on ice and immediately
transported to the LSU Water Quality Laboratory for analysis
Task 5: Determination of hydraulic conductivity of the
experimental area. Efficacy of the MUS system is largely
dictated by the characteristics of the natural soil matrix.
A suitable physical environment for the injection of wastes
and subsequent treatment is required to achieve optimal treatment.
Baseline studies will be conducted to assure proper system operation.
Prior to system initiation background hydraulic conductivities
will be determined. Subsequent measurements following system
initiation will be made to assess any changes in the hydraulic
conductivity of the experimental area. Measurements will be
done through the monitoring wells via the piezometric method.
Task 6: Determination of baseline salinity levels in
the experimental area. Initial analyses will be done to
establish background salinity levels in the project area. Samples
will be drawn from all wells bimonthly for a two month period
and measured for salinity.
Task 7: Determination of dispersion patterns of the
freshwater plume. Dispersion patterns will be evaluated
through dye studies (Rhodamine WT dye) and salinity measurements.
Salinity levels and the dyed water movement with respect to
time and vertical and lateral displacement will be monitored
through monitoring well samples. A calibrated flourometer will
measure dye concentrations. Two dye studies will be done (one
within the first and last quarter of the project). Salinity
measurements will be made during these studies as part of the
routine monitoring process for system evaluation.
Task 8: System evaluation. The experimental protocol
will be designed to address the following questions: (1) are
there limits on the influent water quality that must be adhered
to (bacterial, organic, nutrient, and solids levels); (2) how
much waste per unit time can be injected to avoid bypassing/channelization
of the injectant; (3) what is the cost of utilizing the MUS;
(4) what injection frequency and flowrate allows proper pressure
dissipation within the subsurface; and (5) what type of effluent
quality can the MUS provide. Success will be determined primarily
by questions (4) and (5). State variables of interest can be
broken into operational (injection flowrate, injection frequency,
and injection pressure) and wastewater characteristic (TSS,
bacterial concentrations, organic levels, and nutrient levels.
Data collected from Tasks 4, 5 and 6 will be used to define
specific combinations of parameters to be evaluated. Historic
data collected from previous research will be used as a baseline
for initiating these studies.
Task 9: Sample/data collection. Once or twice a month
(dependant on the time of year) samples will be collected from
the influent source and monitoring wells to determine the effects
of influent water quality and operating parameters on system
performance. Background samples away from the experimental site
will also be collected. Samples will be collected using a peristaltic
pump. Each well will have its own neoprene sampling tube to
prevent cross contamination between wells. In-situ measurements
will include pH, temperature, dissolved oxygen, and salinity.
Salinity readings will delineate the freshwater plume and determine
which wells to collect samples for chemical analyses. Only those
wells exhibiting low salinities with respect to background levels
will be sampled. The samples will be placed on ice and immediately
transported to the LSU Water Quality Laboratory for analysis.
Injection pressures will be continuously monitored using a pressure
transducer and data logger to indicate potential clogging of
the injection zone. Cumulative water volumes injected will be
recorded using a water meter.
All wet chemistry analyses will be conducted in triplicate
and in accordance with Standard Methods (APHA, 1998).
Particle size/distribution data will be collected using a coulter
counter. Analyses will be conducted in the LSU Water Quality
Laboratory. QA/QC protocols, in accordance with EPA guidelines,
are established for each parameter analyzed.
