Project goal

As outlined in the project agreement, the objectives of this project were:

  1. To develop and trial methods for effectively monitoring sludge profiles and accumulation rates and collecting sludge samples from uncovered anaerobic effluent ponds
  2. To determine sludge profiles in approximately 15 existing anaerobic effluent ponds at southern Queensland piggeries
  3. To estimate the sludge accumulation rates in each of the ponds, based on site-specific data relating to the pond loading rate (pig herd, diet and production performance), the original pond dimensions and desludging history
  4. To collect several sludge samples from selected ponds (included one covered anaerobic pond) to determine the solids and nutrient contents and the biochemical methane potential of sludge sampled at various depths and locations within the ponds
  5. To further develop (including calibration) and use an integrated hydrodynamic-biochemical model to provide predictions of sludge behaviour
  6. To determine optimal desludging intervals for ease of pumping while avoiding significant losses of methane potential
  7. To provide recommendations for the design of anaerobic ponds to enhance the ease of desludging
Project summary

The accumulation of sludge in anaerobic effluent treatment ponds used at the majority of Australian piggeries has proved to be a difficult issue to manage effectively for several decades. The major objectives of this project were to address the factors that constrain producers from effectively managing sludge.

Value for producers:

  • Provides individuals with a better understanding of how to manage their anaerobic ponds, allowing them to so with less difficulty and at less cost
  • To provide recommendations for the optimal design of anaerobic ponds which may be used in the future

Recommendations:

  • The optimal pond design as was determined to be 150 day hydraulic retention time (HRT) which balances pond lifetime, capital cost, and performance. This will have a lifetime in the order of 3-5 years without in-situ desludging
  • A deep pond (6m+) is preferable to a shallow pond as it increases holding capacity, decreases impact of sludge accumulation, minimises internal recycles and bypass flows, and enables in situ-desludging
Research enquiries