NC0026921_Technical Assistance_20000717

DENR
NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER QUALITY
RECEVE
illl 1 9 2000
RE G. OFF CE Dow _
ti
r
July 17, 2000
Mr. Roy Lowder
Town of Parkton
P.O. Box 55
Parkton, North Carolina 28371
Subject: Technical Assistance Visit
Parkton WWTP
NPDES Permit No. NC0026921
Robeson County
Dear Mr. Lowder:
A technical assistance v isitation was _conducted at the Parkton Wastewater Treatment
Plant on-July;.'l3,-mop. The primary` focus?of the visit was to identify areas that may
help to enhance the treatment process. As a result of the visit, the following comments
and/or suggestions are offered. Please note that these are only suggestions that may
help in the performance of this facility.
1. In an earlier letter I stated that inflow and infiltration (I&I) was a concern within
your system. I&I can cause a number of problems within a treatment facility. High
flows during_ rain events can cause solids washout, ineffective disinfection, hydraulic
overloading of treatment units, shorter treatment detention times, and excessive grit
accumulation to name a few. T would, suggest that the _Town —begin an intensive I&_'
reim'ov`al program An evaluation of the entire system should be performed. Smoke
testing ill determine areas of concern and then these areas should be prioritized and
work should. be concentrated on high priority areas. During our conversation you
-J mentioned that Parkton was receiving grant money to help repair the collection system.
Past experiences have shown that during the identification procedure, some systems
find a couple of major areas where high I&I enters the collection system. By correcting
t'r= •
these sources first the Town can greatly reduce the amount of I&I to the treatment
system until all areas can be identified and repairs can be made to the rest of these
areas.
NC SLR:3011
MIEWIMMCMI
WATER POLLUTION CONTROL SYSTEM OPERATORS CERTIFICATION COMMISSION
1618 MAIL SERVICE CENTER, RALEIGH, NORTH CAROLINA 27699-1618
PHONE [phone] FAX [phone]
AN EQUAL OPPORTUNITY / AFFIRMATIVE ACTION EMPLOYER - SO% RECYCLED/10% POST -CONSUMER PAPER

2. The chlorine contact chamber should be cleaned on a routine basis; this will prevent solid build-
up and help in the disinfection process. Repairs to thetdrain valves should be made so that one
side of the chlorine chamber can be drained and cleaned while the other side is being used. Please
check to insure that these drains flow back to the head of the plant. It is my understanding that a
flow paced chlorinating system has been installed. The flow pace system should be checked to see
if it is working properly. If this system is not working properly I would suggest contacting the
supplier and arranging a visit by a representative to evaluate and repair the system. A proper
operating flow pace system will indeed help prevent fecal violation during sudden changes in the
flow and toxicity problems in the effluent.
3.jThe results from performing a settleometer test on each ditch showed that the supernatant was
cloudy -and -the -solid -settling- was"very-`fa`st: --This riormal'ly indicates -an o1"der sluEdge and wasting
should--=bep-increased in order -to decrease the Mixed--Liguor` Suspended —Solids (MLSS)-
_
concentration (see enclosed information;): As we discussed, wasting should be done over a period
of a week instead of all at one time, this will be more easily done when the plant's digester is back
on line. The amount of wasting should be determined by the process analyses performed on the
mixed liquor. Although, the settleometer test showed an older sludge, it appeared to be rather thin
in the clarifier's return sludge line. A microscopic test would help determine the type of organisms
present (see enclosed information) and the amount of wasting to do in order to keep the type of
organisms that will best treat the waste stream. With the ditches being only 4.5 feet deep, hydraulic
overloading from high influent flows should be an important concern. The ditches should be kept
clean of sand accumulation. This accumulation of sand greatly reduces the detention time in the
ditches and thus greatly hinders the treatment process abilities. It is recommended that the Town's
engineer look into the possibility of a grit removal system being installed at the treatment plant.
This removal system would prevent grit and sand from filling the treatment basins and wearing out
the equipment. eThistigrit removal -system sfioifid not be considered®an-alternate_soluti n for J
ontrolling the hSt problem_'
4 Ibis -recommended that: additional process control analyses_be_nin_on_a. routine basis. Process
control data t be-very`helpfi l to an operator in determining plant changes and unusual situations
within the process. Mixed liquor suspended solids, centrifuges, settleometers, pH, temperature,
and dissolved oxygen should be analyzed on a regular schedule. This data should be recorded in
detail, so it can be referred to in the future when needed. It was noted that the lab has a fair
amount of lab equipment that was not being used. It is suggested that this lab equipment be
checked. If the equipment is operational, it should be used to help offset contract lab costs for
process analyses. It appeared that the plant has the necessary equipment to perform MLSS and
MLVSS process analyses. These tests would help the operator to determine when and how much
to waste. The only piece of equipment that would be required is a drying oven. (The, Technical3�
Assis; Lance andiCextification Unit_would be happy to provide the test procedure for these analyses=;
tif-you so desire.....:
5. The bricks installed in the influent chamber in order to adjust the flow to each ditch seem to
have really helped. The settleometer showed that each ditch has closely the same amount of solid
concentration. /Sjrnce [his: action has"had a positive result, I-Wou1d suggestvlookiag�at_some
t adjusta'le metal weir being installed fora more permanent ap lip cation_;•

•
6. Clarifiers are ver temperamental and care must be given by the operator to insure calm
conditions eneosea i fo )I. I would suggest developing some standard operating
procedure (SOP) for these units. Unfortunately, it will take some trial and error by the operator to
discover the best operating location for their telescopic valves. As we discussed during my visit,
different settings maybe necessary during the course of the day.
7. 'Ltastl, h-s , gagEgalli t the digester be put ,a into_seivice:' This unit is not being used at this
time. he an c and piping should be evaluated-sinceit has not been used in some time. Although
the digester is small, sludge could be wasted to the digester and thickened before wasting to the
drying beds. The plant's drying beds should be kept clean of grass and properly dried sludge
should be removed in a timely manner. eBhe dryi g edb s are in ,need of some works It is important
to contact an engineer to determine the proper sand to use in these drying beds. I would suggest
removing the old sand, evaluating the rocks and underdrain system, and adding new drying bed
sand to each.
Okla s. alionsiouthined above are ahoseaatwere'the most apparent in contributing to -the plant
.11-or ca ptfahce "' Tf�is hoped that these observations and suggestions will assist you -in --operating
your wastewater facility. Please call me, at (919)-733-0026 ext. 315, to schedule a follow-up visit
or if you should have any questions or need additional information.
Sincerely,
Tony Arnold, WWTP Consultant
Tec ical Assistance and Certification Unit
cc FayettRIe Regi`onal-0ff ce--:-Dori- egister ,
Centr Files `� �` ----_
TAC Files