Solar Biosolids Drying Systems for Wastewater Plants

From Concept to Commissioning — Integrated Project Delivery

Feasibility & Modeling

Each project begins with quantified analysis:

Sludge mass balance
Weather-based evaporation modeling
Required greenhouse footprint
Target dry solids content
Seasonal storage analysis

Example modeled results for a Northern California installation:

Approximately 750 tons dry solids per year
Approximately 2,730 tons of water evaporated annually
Average 74% dry solids output
Solar input of approximately 160 kWh per square foot per year

Sizing is based on evaporation rate per square foot per year and required throughput.

Civil & Structural Integration

Project coordination includes:

Reinforced 8-inch water-tight slab design
Approximately 2 ft 9 in sidewalls supporting machine loads
Snow, wind, and seismic compliance per U.S. building codes
Roof ventilation and air circulation layout
Electrical service and climate control integration

All facilities are designed to comply with applicable U.S. codes and standards.

Financial Structuring

Available options include:

Traditional capital procurement
Design-build delivery
7–10 year service agreement
No upfront capital structure

Illustrative operational impact:

Approximately 2,730 tons per year of water removed
Up to 70% reduction in hauling volume
Reduction of approximately 0.5 full-time equivalent labor
Reduced loader and diesel equipment usage

Solar drying converts disposal costs into controlled infrastructure investment with predictable annual payments.

How the System Works

01

Dewatered cake (typically 18–22% dry solids) is placed at the inlet end of the greenhouse.

02

The Wendewolf tilling drum turns, aerates, and slowly conveys the material down the hall.

03

Solar radiation drives evaporation through high-transmission roof panels.

04

Internal air circulation fans and roof ventilation remove saturated air.

05

Dried product exits at 70–90% dry solids. Systems can be designed to meet your specific dryness target.

The process is continuous and automated. Operators place wet cake at one end and remove dried product at the other.

Core Components

Wendewolf Mechanical Turning System

Heavy-duty drum with engineered paddles
Automated forward and reverse travel
Sidewall-supported drive system
Low energy consumption (approximately 20 kWh per ton of water evaporated)

Agratech Engineered Greenhouse Structure

U.S.-manufactured steel framing
Designed for snow, wind, and seismic loads per U.S. codes
Roof light transmission ≥ 80%
Sidewall transmission ≥ 60%
Polycarbonate, ETFE, or engineered polyethylene options

Integrated Controls & Ventilation

Climate-responsive operation
Gravitational or mechanical ventilation options
Continuous air circulation to remove saturated air boundary layer
Motorized roof louvers and sliding gates

Delivery Models

Traditional design-bid-build
Design-build
Service agreement with fixed annual payment
No upfront capital option available

We can coordinate with your trusted engineer as part of the project team.

Annual payments can be structured below current hauling and operating costs.

Solar Drying Project Development & Financing