Border Environment Cooperation Commission
Water Treatment
Plant in Raymondville, Texas
Type of Project. The project consists of the construction of a
new 4.5 million gallon/day (MGD) water treatment plant for the city of
Raymondville, Texas.
Location of Project. The City of Raymondville, Texas is located in
Willacy County on U.S. Highway 77, approximately 20 miles north Harlingen,
Texas in the lower Rio Grande Valley region of Texas. The project is located
within the 100 km border region as defined by the La Paz agreement. The current
water plant does not meet TNRCC standards and needs to be replaced to provide
potable water for the costumers of the city of Raymondville. The current plant
is rated at 2.5 MGD and was originally constructed in 1934 with an initial
capacity of 0.75 MGD. Over the years the plants capacity has been increased by
various modifications and additional treatment trains. Currently, the plant is
operated at 95% of capacity during normal usage. Peak usage is approximately
2.75 MGD, which is 0.25 MGD over the rated capacity of the treatment plant.
According to the TWDB, the population in 2000 was 10,774. The project considers
a total project population of 13,929 by the year 2030. The city has a water
consumption of 169 gallons per capita per day (gpcd) average.
Description of Project and Tasks. The project considers the construction of a 4.5
MGD water treatment plant, the demolition of the existing plant, construction
of a high service pump station, the construction of a 0.5 MGD ground storage
for the plant and a new water line to tie the existing
distribution system.
Compliance
with International Treaties and Agreements. This project is within the Agreements, that
the United States and Mexico have signed, such as the La Paz Agreement, Border
Environmental Comprehensive Plan, Border XXI Program and the Free Trade.
Human Health and the Environment
Human Health/Environmental Needs. The development of a new WTP will address
several human health and environmental issues for the residents of
Raymondville, Texas. The existing WTP was originally built over 60 years ago
with a treatment capacity of 0.75 MGD. Over the years the city has expanded the
plant to its current treatment capacity of 2.5 MGD. Current demands on peak
days exceed the treatment capacity of the plant. This creates a serious risk
for potential contamination of the public water supply through breakdowns in
the treatment train, and loss of pressure in the distribution system, which can
produce contamination of the water supply. Also, new treatment regulations will
be difficult if not impossible to meet. With a new WTP, the city will have the
ability to meet its current and future demands as well as having the ability to
meet new treatment regulations. The existing WTP cannot meet peak day demands.
This situation creates a technical violation of the Water Hygiene Rules
administrated by the TNRCC. These violations could put the city in a position
of being fined by the TNRCC during upcoming inspections.
Environmental
Assessment. An
Environmental Information Document (EID) was prepared for the city of
Raymondville project, in accordance with State and Federal
requirements.Together with other project documents, the EID formed the basis of
an Environmental Assessment conducted by the US Environmental Protection
Agency, Region 6 (Dallas). On the basis
of the EA and the other project documents, the EPA Regional Administrator has
issued a preliminary determination that the project is not a major Federal
action significantly affecting the quality of the human environment and that
preparation of an Environmental Impact Statement (EIS) is not warranted. This
preliminary finding was published August 4, 2001, and comments from the public
will be accepted by the EPA over a 30 day period from that date. A copy of the EA and FONSI can be found here
FNSI.
Compliance
with Applicable Environmental and Cultural Resource Laws and Regulations. As part of the preparation of the EID,
comments were solicited from relevant Federal and State agencies, including:
The Texas Archeological Research Laboratory, the Texas Historical Commission,
the US Fish and Wildlife Service, Texas Parks and Wildlife Department, Federal
Emergency Management Agency, and the United States Army Corps of
Engineers. Project approval responses
were obtained from all agencies contacted.
The project is in compliance with all applicable environmental and
cultural resource laws and regulations, including among others, Significant,
Unique or Important Farmlands, National Natural Landmarks, Wilderness
Protection, Wild and Scenic Rivers, Wetlands Protection, Floodplain Management,
Fish and Wildlife Protection, Endangered Species Protection, Historical,
Architectural, Archeological, and Cultural Sites, Air Quality, and
Environmental Justice.
.
Appropriate Technology. The proposed water
treatment plant will utilize standard water treatment processes including
coagulation, sedimentation, filtration and disinfection. The final engineering
design of the plant will include pilot studies to determine the potential of
using membrane filtration and microfloc treatment as well as conventional
treatment. These pilot studies will determine the most efficient and effective
way of treating the water. While it is anticipated that headworks, building,
etc., will be sized to handle 4.5 MGD, the treatment capacity will be phased in
with a 3.5 MGD treatment capacity.
Coagulation. This process uses chemicals to catalyze
the aggregation of particulate matter in the raw water. It is important for
coagulation that there be rapid mixing of chemical coagulant. This is first
phase is called coagulation/mixing. The second part of coagulation phase is
flocculation.
Pilot studies will determine the best process for
coagulating the influent water to the plant. The preliminary engineering report
for this project mentions the use of conventional coagulation, used by the city
currently. Newer technologies, specifically membrane treatment and synthetic
coagulant computer controlled technology (e.g. Microfloc) are already in use by
some of the providers in the area with good results. These technologies will be
primary focus of the pilot study.
Sedimentation. The process is based on the
non-turbulent steady flow through a series
of canals allowing the flocs to naturally settle out and collect on the
bottom of the sedimentation basis. Sedimentation basins may have a rectangular
shape with length being several times longer than width or circular design with
radial flow from the inside to the outside. The basin will be provided with
baffles to uniformly distribute flow. The system will be designed so that there
are several settling basins in parallel, allowing for maximum flexibility and
redundancy.
Filtration. The filtration process polishes the
water by removing the remaining flocs using granular material, usually sand.
Filters are differentiated by the rate of filtration they allow. Slow sand
filters are the older technology. Rapid sand filters is the other technology,
in which beds tend to be smaller and shallower than slow sand filters. Another
trend in filtration, which may be considered in the design of Raymondville WTP,
concerns use of dual media. Multiple media are being used increasingly to
attain the greater chemical removal standards required under recent
regulations. The usual alternate media are anthracite or activated carbon. The
alternate media may be placed in a different layer than the sand or mixed with
it. If a synthetic coagulate process is used, the coagulation and filtration processes will be combined
into one factory made module. There is not a sedimentation process with this
type of treatment. Rather the floc is embedded in the media and must be
periodically washed out. Backwash timing is critical for a good final result,
so a computer is used to monitor the module for head increase as the filters
become occluded.
Disinfection. The
oxidants used in disinfection include chlorine gas, chloramines, chlorine
dioxide, ozone or ultraviolet light. The final method of disinfection will be
decided after the pilot studies. Currently the city is using chloramines as a
disinfecting agent.
O&M
Plan. The city of Raymondville has an operations manual
for the present plant. The engineer will be responsible for development of an
operation and maintenance manual. This O&M manual will be completed prior
to completion of construction. All personnel will receive training prior to
start up of the WTP manual. The staff has long-term experience in WTP operation
with the average time working in plant operation of almost 20 years. The Chief
Operator has a B license and all operators have at least a C license. The
design engineer will prepare a new O&M plan as part of the design
engineering contract with the city. Initial startup of the system will include
testing of the components prior to acceptance by the owner to assure that they
properly perform their intended function. If there are new procedures used in
WTP operation, the company providing the equipment will be required to conduct
training on site for city staff in operating and maintaining the new equipment.
Compliance with applicable design norms and regulations. The TNRCC has regulatory authority for
water treatment plants in the State of Texas. Permits will be required for the
closure of the existing WTP and a permit will be required for the new plant.
The TNRCC will also have review authority along with the TWDB on the design of
the project, which must meet State design criteria.
Financial
Feasibility and Project Management
Financial Feasibility.
The
financial analysis to determine the funding structure of the project and the user
rates to guarantee the financial sustainability of the operating agency has
been completed.
|
Estimated Cost |
|||
|
Concept |
Amount (US$) |
||
|
|
|
Water Treatment Plant |
4,525,000 |
|
|
|
Demolition of existing plant High Service Pump Station |
200,000 400,000 |
|
|
|
Ground Storage Distribution System
modifications Engineering fees Other Items |
375,000 130,000 939,200 876,143 |
|
|
|
Total |
$7,445,343 |
|
Current Water Expenses (Annual) |
|||
|
Concept |
Amount (US$) |
||
|
|
Treatment Distribution Office Expenses |
390,276 235,702 123,588 |
|
|
|
|
TOTAL |
749,565 |
Financial Structure
|
Source |
Amount (US$) |
% |
|
Texas Department of Agriculture (loan) |
3,245,478 |
43.6 |
|
BEIF (grant) |
4,199,865 |
56.4 |
|
Total |
7,445,343 |
100% |
Rate
Model: It will be a $ 1.00 increase during the first
year and a 5% adjustment for the average residential rate during the next 7
years. Additionally the city will receive Transitional Assistance Funds from
BEIF for $ 258,268 during the
next 7 years.
Project
Management. The City has adequate personnel to handle the
proposed infrastructure and to respond to any potential emergency that might
arise during operation and maintenance of the project.
|
SINGLE
FAMILY RATES (US$) |
|||
|
|
2001 |
2002 |
2003 |
|
Average Monthly Water Bill |
$ 23.75 |
$ 25.45 |
$ 26.75
|
|
|
2004 |
2005 |
2008 |
|
Average Monthly Water Bill |
$ 28.09 |
$ 29.50
|
$ 34.15 |
*considering a typical consumption of 10,000 gallons per
month
Comprehensive Public Participation Plan. The Raymondville public participation plan was submitted on November
17, 2000 following the public participation guidelines and subsequently
approved per BECC requirements.
Steering
Committee: The steering committee was formed on October 18,
2000, and includes Alma Chavez, of the local Chamber of Commerce; Viola
Vasquez, of Amigos Del Valle; Guy Fambrough, of the Willacy County Industrial
Foundation; Alicia de la Paz, of Su Clinica Familiar; Cristina Caldera, Richard
MacDonald, Aurora Pedraza and Rafael Cisneros of Valley Interfaith.
Local
Organizations: Organizations to be contacted include Valley
Interfaith, Chamber of Commerce, Industrial Foundation, Raymondville Rotary and
Lions Clubs, Amigos Del Valle, the Independent School District, the Parent
Teachers Organization, the Ministerial Alliance and the Spanish Ministerial
Alliance.
Public
Information: Project
information has been available at City Hall and the local public library. Fact
sheets have been available that include general information on the project such
as, technical, environmental and financial components of the project. The fact
sheet has been made available to service organizations, community groups and
available at the City Hall, County Courthouse, and local library.
Public Meetings: A public meeting took place on November 28, 2000 to present the technical
information of the project. The financial public meeting was held on July 23.
Definition and Principles. The project complies with BECCs definition of
Sustainable Development: Conservation oriented social and economic
development that emphasizes the protection and sustainable use of resources,
while addressing both current and future needs, and present and future impacts
of human actions. This project is to
provide potable water for the costumers of the city of Raymondville, Texas.
Present and future generations will benefit from this project by connecting to
a safe and dependable water supply by providing sufficient treatment capacity
to meet current and future demands. The water treatment system project is
centered on providing an improved quality of life for human beings.
The project provides environmental
protection by providing water with the quality standards that the costumers
require.
Institutional and Human Capacity
Building. The project will be managed by the local
sponsor and will be constructed and operated in conformance with the
requirements of both regulatory and funding agencies. An aspect of this project
that will build institutional capacity is the creation of reserves for any
potential emergencies.
Conformance with Applicable
Local/Regional Conservation and Development Plans. The
project is in conformance with the approved Water and Wastewater Master Plan
developed for the city in 1998. The city reviewed and the TWDB the Plan for
compliance with generally accepted engineering principals. The project was
listed as a top priority of the city in order to meet current and future water
demands. The project was also included in the Regional Water Plan developed by
the Brown-Lewis planning effort and approved by the TWDB.
Natural Resource Conservation. The Drought
Contingency Ordinance was approved by the city on August 22,
2000. This plan identifies methods to save water, which has the additional
impact of decreasing wastewater flows by providing methods of reducing water
usage. In addition to the Drought Management Ordinance, this project will allow
the city to operate the new plant more efficiently which will save operating
costs as well as water that is currently lost in the treatment process at the
existing plant.
Community
Development. The development of
this new
water treatment plant will provide sufficient capacity to meet the water needs
of the citys costumers for the next 25 30 years. With sufficient water
treatment capacity, the city will be able to manage growth within its available
resources, while providing an affordable water supply to costumers.