LPWRP Biosolids Project

BioSolids Dryer  LPWRP-Biosolids-Process-Schematic   

July 23, 2018 Update

        Digester Steel Cover Fabrication Digester Steel Cover Install Digesters & Digester Building  Phosphorus Precip Reactor Tank Placement

       A summary of accomplishments since last update:

1.     Anaerobic digester tanks and building installation – final testing and insulating of the fix-cover tanks remain. Installation of the membrane, gas-holder cover on digester 3 remains.  Estimated to be complete by end of September 2018 including all internal piping, mixing system, heat exchangers, boilers, etc.

2.     Concrete repairs made to existing tankage for future installation of de-ammonification system.

3.     Thickened solids storage tank rehabilitation has begun.

4.     Gravity thickener rehabilitation 90% complete.  Concrete tank repairs completed and completely new mechanism, center column, drive, etc. installed.

5.     Pipe gallery work including piping and pump installation.

6.     New prefabricated motor control center building, electrical distribution equipment, and substation installed and online.

7.     Installation of phosphorous precipitation reactor, chemical storage tank, and building.

8.     Installation of digester flare system nearly complete.

9.     Water main loop installed.

10.  Natural gas extended to the treatment plant by local utility, onsite gas main installed across the Plant site and service connection installed  at the points of use. 

11.  Gravity Belt Thickeners and polymer feed systems installed and online.

12.  Primary solids screens installed and online.

13.  New solids conveyors and temporary loadout installed and online.

14.  New temporary lime stabilization system and building installed and online.

15.  Phase 2 - Dryer Building and Dryer Installation design, bid, and contract negotiations complete. Select demolition of existing lime building has begun.

The project remains on track for completion of Phase 1 in July 2019 and Phase 2 in October 2020.


Gravity Thickener Rehab Phos Precip & Temp Lime Stab Systems PS 8 Setting Gravity Belt Thickener Solids Screens


August 22nd 2017 Update:

Biosolids Project Biosolids Project Biosolids Project Biosolids Project Biosolids Project

Phase I construction continues on foundation preparation and underground utilities.  Contract is 177 days into construction of a total 884 days in the contract or 20% complete by time.  It is on track for earned value.  Phase II 60% design received July 2017 and under County review.  A request for proposals was advertised in July for biosolids management services.  Award to responsive and responsible bidder is pending and contract is expected to begin February 1, 2018 which will provide for a temporary Class B lime stabilization process for approximately one year then transition to distribution of anaerobically digested Class B product and ultimately distribution of dried biosolids if the contract is extended to its maximum five-year term.

August 22nd 2017

April 25th 2017 Update: 


Howard County Executive Breaks Ground on New Biosolids Facility



Click Video Links below to view the Ground Breaking Ceremony on March 25th below.

Short Version Video

Long Version Video 

March 15, 2017 Update:

Little Patuxent Water Reclamation Plant 8th Addition –Purchasing has issued purchase order to contractor, Clark Construction based upon their Phase I Guaranteed Maximum Price (GMP1) proposal.  Notice to Proceed provided to Clark February 24, 2017.  Clark has mobilized and begun select demolition.   The design and construction team met with Synagro to plan for temporary processing equipment during construction of Phase II (dryer building) now proposed in same location as existing lime stabilization process.  Design of Phase II is ongoing (<30% complete).  Next design workshop will be March 24, 2017 to get County buy-in of dryer building layout.  The 30% submittal is expected in April. A groundbreaking ceremony is planned for April 25, 2017 at 2pm.  

November 14, 2016 Update:
The project is on schedule.  The Engineer’s 90% Phase1 contract documents were received October 27th.  The Design team is reviewing the 90% submittal.  The CMAR is preparing their 90% Cost Estimate.  The CMAR is bidding for subcontractors.  GMP1 is due December 9th.  Targeting to have contract negotiated and awarded by February 17th.  The dryer system vendor has been given NTP and is preparing for 1st design review meeting December 1st.  Coordinating with Synagro on their operations during construction and transitioning to lime stabilization of digested solids while dryers are being installed.  

The following is taken from the Executive Summary of the Preliminary Engineering Report, November 2014 prepared by HDR Engineering, Inc.:


Howard County is proceeding with a Biosolids Processing Facilities Improvements project (the Project) at the Little Patuxent Water Reclamation Plant (LPWRP).  The Project will implement the recommendation from the Countys 2013 Biosolids Master Plan Study to replace the current biosolids stabilization practice, consisting of advanced lime stabilization of undigested primary and waste activated solids, with anaerobic digestion and direct heat drying.  While both stabilization processes produce Class A, exceptional-quality (EQ) biosolids, beneficial use of lime stabilized biosolids is limited to bulk agricultural land application, which is becoming more restricted under Maryland regulations.  Anaerobic digestion and heat drying produces a more versatile biosolids product suitable for a variety of beneficial uses.  The recommended improvements provide the County with reliable, cost-effective, and socially responsible treatment and beneficial use of LPWRP biosolids in a changing and unpredictable regulatory environment, as elucidated in the objectives statement for the Master Plan Study.


The recommended improvements also provide to the County the benefits of biosolids volume reduction and annual operations and maintenance cost savings.  As shown by the comparison in Table ES-1, replacing advanced lime stabilization with anaerobic digestion and heat drying is expected to reduce biosolids volume and truck traffic by over 80 percent and save almost $2 million/year in annual operations and maintenance costs.


Table ES-1  Biosolids Improvements Volume Reduction and Cost Savings




Advanced Lime


Anaerobic Digestion and Heat Drying


Type of Class A, EQ biosolids produced

Limed Dewatered Cake

35% to 40% solids

Dried Granule

90% to 95% solids

Total biosolids volume, wet tons/year



Biosolids hauling, average trucks/day



Biosolids operations and maintenance, $/year

$4.4 million

$2.5 million


The Preliminary Engineering phase of the Project was undertaken to:


·         identify viable beneficial use markets for dried biosolids in Maryland and neighboring states;

·         determine which drum and belt dryer options can reliably produce the type of dried biosolids preferred in each viable beneficial use market;

·         evaluate and select the recommended alternatives for drying, anaerobic digestion, and supporting solids handling process improvements;

·         refine design criteria, equipment configurations, and facility layouts for the recommended solids and biosolids improvements to serve as the basis for final detailed design; and prepare a preliminary opinion of probable construction cost for the Project for the Countys capital improvements program budgeting.



Key decisions that emerged from the Preliminary Engineering evaluations to align selected alternatives and preliminary design configurations with the Countys biosolids management objectives are summarized in Table ES-2.


Table ES-2  Key Preliminary Design  Decisions