HomeMy WebLinkAbout09. Status update regarding contracts for lime and gases9.
AGD
Central Contra Costa Sanitary District
September 22, 2016
TO: FINANCE COMMITTEE
FROM: ANN SASAKI, DEPUTY GENERAL MANAGER iffr
SUBJECT: STATUS UPDATE REGARDING CONTRACTS FOR LIME AND GASES
At a previous Finance Committee meeting during a discussion of blanket purchase
orders, a question was raised regarding the contracts for lime and gases. The following
is a status update on these two contracts.
Lime
For the past 20 years, the District has purchased calcium hydroxide (lime) from
Gilmour & Company (Gilmour) out of Salt Lake City, Utah, for use in sludge
conditioning. The product purchased is a waste product from the production of
acetylene. The raw product is called carbide lime and when hydrated it off gasses
acetylene. Gilmour has established contractual relationships with five California
acetylene suppliers to recover and resell the waste lime. The five locations are Fowler,
Stockton, Sacramento, Fresno and Bakersfield. Gilmour has installed recovery
equipment at some of the locations and works with the supplier to manage the recovery
and thickening of the product. The District is the primary recipient of this waste product.
Gilmour has also sourced commercially available lime from Riverside to supplement
times of low availability of the waste lime. Since there is not much control on the waste
lime supply, the District purchases the more expensive commercial lime as needed
through Gilmour for logistical and trucking reasons. If the waste lime source is reduced
to a point that more commercial lime is needed, then it would make sense to bid out the
supply of commercial lime. However, at this time, staff recommends that the District
continue to purchase lime from Gilmour due to their supply of the waste carbide lime.
The cost from each source is listed below.
Sourced through Gilmour:
• Fowler = $154/ton plus $200 delivery fee due to distance
• Fresno = $154/ton plus $200 delivery fee due to distance
• Stockton = $1541 ton delivered
• Sacramento = $154/ton delivered
• Bakersfield = $230/ton delivered
• Riverside = (commercial lime 35 percent slurry) $5001ton delivered
Finance Committee
September 22, 2016
Page 2
Sourced through Univar:
• San Jose = (commercial lime 45 percent slurry) $529/ton delivered
In 2013, when there was a temporary shortage of waste lime from the Bakersfield
supplier, the District looked into purchasing equipment and producing lime slurry on site
as well as reducing the lime feed. At that time, staff concluded that the cost of sourcing
the waste lime through Gilmour was still more economical than purchasing commercial
lime or producing lime on site.
Lime is used in the sludge at a feed rate of 3.2 tons per day. It is used for three
reasons:
1. pH conditioning of sludge for effective polymer conditioning and dewatering;
2. Prevent glassing (melting and clinker formation) of the inorganics during incineration;
and
3. Bind copper in the sludge to prevent it from being reintroduced to the effluent via the
centrate.
There have been recent tests and efforts to reduce the amount of lime used, and a pilot
is being planned to reduce or eliminate lime use. If it is determined that lime addition
can be greatly reduced, Gilmour will need to find another end user since delivery of
small quantities is not profitable for them. At that point, the District may need to bid
commercial lime.
Gases
The District currently has a contract with Praxair to provide gases for use in the
Instrumentation Shop for the calibration of instruments for landfill gas, the furnace, and
the cogeneration system. This contract is one of five blanket purchase orders for gases
used throughout the Treatment Plant in the Instrument Shop, Mechanical Shop, and
Laboratory. We are in the process of preparing a scope of work to consolidate all of the
Treatment Plant needs into one contract for bidding in November 2016. It is estimated
that the District spends $100,000 annually on these gases.
N:IPOSUPIBoard of Directors\Board - Finance Committee120161Lime and Gases Contracts 09-22-16.docx