Anaerobic Wastewater Treatment

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RWL Water has decades of experience implementing anaerobic digestion systems to process organic waste and produce biogas.

What is Anaerobic Digestion?

Anaerobic digestion is a process in which microorganisms break down biodegradable material in the absence of oxygen. It can be used to process a wide range of organic material, from food waste and grass to waste paper and animal waste.

The process produces biogas — primarily methane (CH4) and carbon dioxide (CO2) — that can be converted into electrical and thermal energy.

The anaerobic breakdown of organic matter is a three-stage process. During the transformation of the organic matter, intermediate compounds known as metabolites are formed.

When the process of digestion is complete, a liquid sludge remains. Any organic material that has not been completely broken down will be separated into solids and liquids. The liquid can either undergo aerobic treatment or be recirculated through the digestion process. The solids can be used as fertilizer or disposed of by a company specializing in solid waste disposal.

RWL Water is an expert in the implementation of anaerobic treatment solutions designed to treat both:

  • primary sludge or very concentrated waste such as animal manure or wastewater from slaughterhouses
  • wastewater polluted by soluble organic substances, such as those from industrial processors including breweries, sugar refineries, and candied fruit manufacturers

RWL Water has developed its own granular anaerobic sludge technology, which requires very low volumes of water and has high operational stability.

Anaerobic Digestion for Businesses Across the Globe

Adopting renewable energy sources will help European Union nations meet the European Commission’s 20-20-20 climate and energy targets. Biogas can help since it not only meets renewable energy standards, but also actively helps fight environmental pollution.

RWL Water’s solutions are unparalleled at improving business opportunities for manufacturers as they work to improve quality and reduce their green and blue footprints through the use of renewable energy.

RWL Water’s expert chemists and engineers implement technologies and design solutions that minimize waste disposal costs and help companies transform liquid and solid treatment byproducts into electrical and thermal energy.

The cogeneration plants used for this are designed to be simple and compact, with an efficient and focused technology.

How Much Energy Is Produced by Anaerobic Treatment?

The correlation between the quantity of material put into the anaerobic digester and the quantity of biogas generated depends on many variables. Therefore, the “conversion efficiency” of an anaerobic digestion plant is highly dependent on how the designers and engineers are able to combine, design, and control these variables.

Biogas production depends on the waste stream being treated. The production of both biogas and methane from various waste products are provided in  this chart.

Biogas Production
(Nm3/ton)
Methane Production
(Nm3/ton)
Cheese-Whey34.419
Scotta33.318
Bovine Slurry2514
Meat Meal220145
Corn Silage200110

Biogas production and methane percentage for different types of biomass.

RWL Water’s anaerobic wastewater treatment systems are specifically designed and optimized for agro-industrial users and have key features that set them apart. First, the external mixers and heat exchangers on the components are placed so maintenance can be performed without stopping the plant’s normal operations.

Programmable logic controllers allow for remote control, enabling continuous, correct plant operation. Adding to process stability is an external recycling system that maintains a steady flow inside the reactor without the use of preacidification stages.

Anaerobic Digestion Case Studies

Case Study: Amadori

Anaerobic digestion produces thermal energy.

RWL Water added an anaerobic digestion system to the wastewater treatment plant at the Amadori facility in Teramo, Italy, without disrupting operations.

Amadori SpA, a leading manufacturer in Italy, produces a wide variety of meat-based dishes for the food service and consumer markets. Amadori already had a wastewater treatment facility at its plant in Teramo, Italy, but it needed to increase production while reducing disposal costs, particularly those associated with primary sludge treatment. The challenge was to build and activate new equipment without disrupting normal operations of the existing plant and chicken slaughterhouse.

To address these needs effectively, in 2008, RWL Water Italy restructured the existing wastewater treatment system. An anaerobic digestion system, which introduced a waste-to-energy component to the facility, was added, along with a nitrification-denitrification system. The system treats effluent from the poultry slaughterhouse, as well as waste from the product breading process. The plant, which has a maximum capacity of 3,150 cubic meters a day, produces 30.2 MW of power a day.

Case Study: Birra Peroni Group

Anaerobic treatment creates thermal energy.

RWL Water installed an expanded granular sludge bed reactor at the Birra Peroni facility in Bari, Italy. The reactor produces thermal energy for the factory boiler.

The Birra Peroni Group is part of the SABMiller Group, one of the world’s leading brewing companies. Peroni has been brewing beer for more than 160 years with an annual peak production of 450,000 cubic meters — more than 118 million gallons. The company’s main brands include Peroni, Nastro Azzurro, and Pilsner Urquell.

The Peroni facility in Bari needed to be re-engineered to increase production. The existing wastewater treatment plant from 1996 was inadequate and outdated. The main challenge was to retool, install, and start up the equipment without interfering with the company’s normal production operations.

RWL Water installed a new expanded granular sludge bed (EGSB) anaerobic reactor. It and two existing anaerobic digesters produce thermal energy for the factory boiler. The plant has a maximum capacity of 2,200 cubic meters a day.

Decades of Anaerobic Treatment Expertise

All RWL Water anaerobic technologies are engineered to match your unique water treatment challenges. Our equipment is ruggedly built, specifically designed to provide users with extended, trouble-free operation.

Let our technical experts help you determine the proper sizing, layout, and operation of your anaerobic treatment system.

Contact RWL Water for more information about our anaerobic treatment solutions, or to request a quote.