Zero-emission water treatment systems for pig farm discharge

ENTRY DATE: 11.11.2013 | LAST UPDATE: 11.11.2013

CATEGORIES:

  • Water Resources
  • Wastewater treatment

TECHNOLOGIES MATURITY:

At the demonstration testing stage

Technology Owners:

AQUA Corporation 
EX Research Institute
Chichibu Aquatic Life Institute

Needs Address

The need to reduce the impacts of deteriorating quality of public waters (particularly enclosed water bodies, etc.) as a result of climate change, in areas that may face declining sanitation conditions.

Adaptation effects

  • Limiting the deterioration of water quality in enclosed water bodies due to the effects of climate change, etc.
  • Prevention of deterioration of sanitation conditions and reduction of disease risk due to climate change

Overview and Features

  • Treatment of wastewater generated from pig farm manure using chlorella continuous culture equipment (referred to below as the MIYABI system) prevents contamination of drinking water and agricultural water by untreated wastewater from pig farms, and improves the water environment.
  • The system’s aim is to create a circulation system that reduces the amount of wastewater discharged from pig farms to the greatest extent possible, by concentrating chlorella green water generated during the urine treatment process and fermenting it as lactic acid to be included in pig feed, as well as by recycling treated water for cleaning the pig farm, adjusting the moisture content of compost, and using it in hydroponic growing, etc.
  • The image below shows the flow of treatment processes at a pig farm.

Image: Flow of treatment processes at a 10-animal pig farm

Source: Model project for improvement of the Asian water environment, 2012 (The Zero-Discharge performance by treating waste water from pig farms), Administrative Report

Cost

Cost-Benefit Analysis and Investment Recovery Time

  • This analysis compares existing lagoon technology with the proposed system in terms of costs and investment recovery time, for a pig farm operating on the scale of about 200 animals.
  • In terms of cost-benefit analysis, the MIYABI system increased sales revenues by 25 percent  compared to the use of lagoons, due to the benefit of providing animal feed made of fermented chlorella liquid. As a result, the benefit-to-cost ratio for the MIYABI system was 41%, higher than the 28% for lagoons.
  • For the calculation of years required to recover investments, the total investment required for zero discharge from lagoons was 550,400 Malaysian rupees, versus 390,980 Malaysian rupees for the MIYABI system, with the latter being less due to the lower cost of construction of an artificial wetland. Dividing investment amount by revenues, the recovery time is 7.1 years for lagoons, versus 3 years for the MIYABI system.

Figure: Layout plans for the MIYABI system and lagoons

Source: Model project for improvement of the Asian water environment, 2012 (The Zero-Discharge performance by treating waste water from pig farms), Administrative Report

Table: Cost comparison of the MIYABI system and lagoons

Source: Model project for improvement of the Asian water environment, 2012  (The Zero-Discharge performance by treating waste water from pig farms), Administrative Report

Energy source

Electricity

Ease of maintenance

  • Manure must be raked out once each day by use of a scraper.
  • Urine is directed into a urine pit through a discharge pipe.

Technology performance

Below is a water quality comparison between the MIYABI system and lagoons. The MIYABI system shows better performance than lagoons in terms of suspended solids, BOD, and T-N removal, etc.

Table: Water quality comparison of the MIYABI system and lagoons

Source: Model project for improvement of the Asian water environment, 2012, (The Zero-Discharge performance by treating waste water from pig farms), Administrative Report

Considerations

Technical Issues

Technical issues identified by the FY2011 Asia Water Environment Improvement Model Project, and means to address them, are indicated below.

Technical Issues

Solutions

1. Treated water stabilization

In order to prevent the build-up of nutrients and persistent substances, process the treated wastewater in the artificial wetland, rather than recycling it for cleaning purposes.

2. Concentration of chlorella green water

Small facilities can concentrate it into poly-glu, while large facilities can use centrifuge separators.

3. Sterilization

Move toward halting sterilization.

4. Rainwater countermeasures

Raise the reactor walls by 10 centimeters.

Construct a rainwater dugout

5. Issues with Fe ion groundwater

Deal with by using sand filter, settling tanks

Issues for Popularization of the Concept

The following items need to be considered and confirmed in order to deal with issues of popularization.

1. Cost reduction

To facilitate the use of the MIYABI system, it is essential to reduce construction and maintenance costs as much as possible.

2. The benefits/effectiveness of chlorella fermented liquid, and legal implications for its use in pig feed

It is necessary to test the effectiveness of chlorella fermented liquid, and to verify legal aspects required for use as pig feed.

3. The use of pig manure

In Islamic regions, in some cases it is not easy to use pig manure.

4. Standardization of artificial wetlands

Because it is necessary create an artificial wetland to accept the concentrated effluent including nutrients from the MIYABI system, it will be important to consider and demonstrate the design of a standard model artificial wetland.

5. The handling of intellectual property rights

When introducing the system, it is necessary to confirm the status of intellectual property rights for technology and expertise belonging to the companies involved. 

Co-benefit, suitability for developing countries

It is possible to achieve zero emissions by feeding pigs the chlorella green water fermented liquid generated as a byproduct of wastewater treatment.