Continuous aerobic treatment of piggery slurry for odour control scaled up to a farm-size unit

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Effective aerobic treatment of piggery slurry was achieved in a continuous farm scale process sited at a small piggery (2000 pigs). The plant design and the operating conditions were based on data obtained from pilot-scale studies with the aim of preventing or reducing odours from pig slurry at a minimum cost. Raw slurry was separated before passing into the main treatment vessel. Aeration was achieved by recirculating of slurry (achieving jet mixing of the tank contents) through a venturi where air was entrained. Aeration was controlled to maintain redox potential between 100 and 200 mV Eh. Slurry was added and withdrawn at hourly intervals, to provide nominal residence times of 1, 2 and 4 days.
The performance of the aerobic treatment process in terms of COD reduction could be predicted using data from laboratory and pilot-scale experiments. Some allowance could be made for minor feed fluctuations but a more comprehensive model will be necessary for predictions where larger variations occur in operating conditions. Assessments were made of odour quality using dynamic dilution olfactometers for odour strength, and volatile fatty acids (VFA) concentration as an indicator of odour offensiveness. Results indicate that pilot-scale experiments may overestimate by 10a

Alteration of Nutrition as a Mean to Reduce Environmental Pollution by Pigs

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The introduction of an extra feed (phase feeding) during the production cycle leads to 2 to 10% reduction of P and N excretion in the manure. With the use of microbial phytase, the digestibility of P can be improved by 20% or more resulting in less or no P supplementation for growing and pregnant sows and a reduction of P excretion from 20 to 30%. The excretion of N can be lowered by 20% by the incorporation of synthetic amino acids and lowering the crude protein level in the diet by 2%. Most of those options leads to an increase in the price of the mixed feed. More constraints may come later for copper, zinc and potassium.

This article is very complete and thorough with the implication of the pig nutrition and environmental pollution.

A review of the control of odour nuisance from livestock buildings: Part 3, properties of the odorous substances which have been identified in livestock wastes or in the air around them

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The literature on the odorous compounds identified in livestock wastes or in the air around them has been reviewed, and the resulting information on the properties of these compounds is presented in a series of tables. The total number of compounds which have been identified is 168, of which 30 have odour detection thresholds lower than or equal to 0A

Effect of Protein Content of the Diet on Nitrogen Excretion by Pigs

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Reduction from 15 to 20% of N excretion was realized by lowering the crude protein content of the diet of 10% during the growing period and 7% during the finishing period.

Aeration Experiments for Swine Waste Composting

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Development of a Calculation Model for Predicting the Amount of N Excreted by the Pig: Effect of Feeding, Physiological Stage and Performance

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The model showed that interesting effect when the performances of the production system are improved. More piglets produced per sows and also improvement in the feed conversion ratio have an effect on the nitrogen output of the system. the average daily gain did not have a direct and important effect.

A Mathematical Model for Estimating the Amount and Composition of Slurry from Fattening Pigs

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As models are a representation and simplification of the reality, specific and complex interactions between factors are difficult to evaluate and to integrate in a model. This model could be of interest when investigating the effect of different diet formulation on the manure production and the nutrient excretion.

A Review of the Control of Odour Nuisance from Livestock Buildings: Part 2, The Costs of Odour Abatement Systems as Predicted from Ventilation Requirements

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English pound (L).

Biological Removal of VFA from Animal Wastes (Volatil Fatty Acids)

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The use of a bioscrubber and compost as treatment for VFA on a laboratory scale has been very effective. However even if the VFA play an important role in odour emissions, no information has been given on the possible odour reduction.

Pig building dustiness as affected by canola oil in the feed.

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Experiments were performed in a pig grower-finisher room to determine the effect of canola (rapeseed) oil treatment of feed on several indices of dustiness. The effectiveness of the oil treatment was assessed over 18 weeks by measuring the respirable dust particle counts (RPC), airborne dust inhalable mass concentration (IMC), and dust sedimentation rate (DSR). The dry feed contained 0% and 2% canola oil on alternate weeks. The pen floors were partially slatted during the first 8 weeks and were totally slatted during the last 10 weeks. The mean RPC was 45% higher for the oil treatment compared to the no-oil treatment. The mean IMC was 31% lower for the oil treatment compared to the no-oil treatment. The mean DSR within the room was 7% lower and within the recirculation duct was 9% lower for the oil treatment compared to the no-oil treatment. None of these differences were statistically significant (P>0.1).