It seems that since 2002, Miami-Dade is still drafting a plan -- you might ask, where's the
stuff being disposed of now?
Miami-Dade County’s Biosolids Master Plan
This project includes the evaluation of Miami-Dade Water and Sewer
Department’s (MDWASD) wastewater and water treatment facilities and
operations, and preparation of a county-wide master plan to address biosolids
treatment and disposal over a 20 year planning horizon. Project objectives
a) Investigating specific biosolids management issues at each WWTP;
b) Evaluating the cost and benefits of increasing the level of treatment at all
biosolids processing facilities to meet Class AA standards; and
c) Developing biosolids treatment alternatives taking into account costs and
regulations, as well as environmental and public acceptance factors.
September 4, 2007
(Excerpt from the Executive Summary, page 1-14)
1.7 Biosolids Master Plan
On the last renewal of the sludge hauling contract in 2002, MDWASD was
directed to proceed with addressing the feasibility of treating all biosolids to
Class AA level. This upgrade increases the disinfection levels of the biosolids,
allowing for additional applications sites, such as use as fertilizer, for disposal.
The first step taken by MDWASD was to issue a Request for Information
regarding the alternatives available to achieve this goal. On the receipt of the
various proposals, MDWASD decided to obtain the assistance of a consultant
to evaluate the present biosolids processing and to make recommendations as
to the appropriate upgrades to attain the Class AA treatment levels in the
form of a Biosolids Master Plan.
Camp Dresser &McKee, Ine (CDM) was selected for this assignment. The
consultant, CDM, was retained. A draft Biosolids Master Plan was submitted to
the MDWASD on March 31, 2007 and is presently under review. In the Plan
preparation, a number of technologies were evaluated on various criteria
including technical and cost bases. The final three technologies evaluated are
- Advanced Digestion utilizing two phases. Higher temperatures would be
utilizedfor the first high-rate phase to achieve the pathogen reductions
necessary for ClassAA treatment levels.
- Composting. An upgrade to the present system employed at the SDWWTP
so that solar drying and composting would take place in enclosed areas so
that the effects of rain would not impede the process.
- Rotary Heat Dryers. Biosolids are dried using heat in rotating drums to form
These alternatives produce different product consistency at solids
concentrations ofapproximately 25, 80, and 95 percent, respectively. These
factors affect the numbers and reliability of disposal sites for the processed
In view of the uncertainty of the continued sustained use of the various
disposal sites for the products for each of these technologies, CDM has
proposed that a diversified approach be taken. Under this plan, facilities using
each of these technologies would be constructed for designated proportions
of the sludge production. Accordingly, for each of the overall wastewater
facilities alternatives developed, the same groupings of biosolids processing
technologies were included. Taking into account improvements to the present
biosolids systems at the CDWWTP and SDWWTP, the project costs for the
facilities under the diversified approach are $360,180,000 and $356,670,000
for the alternatives with and without the new plant in the central west part of
the County. MDWASD is presently reviewing Biosolids Master Plan draft and
the consultant recommendations.
In Trees We Trust
2 weeks ago