The Influence of Alkalization and Temperature on Ammonia Recovery from Cow Manure and the Chemical Properties of the Effluents

Mohammed-Nour, Ahmed; Al-Sewailem, Mohamed; El-Naggar, Ahmed H.

doi:10.3390/su11082441

Cited by 30 publications

(23 citation statements)

References 43 publications

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“…Urea and ammonia were previously indicated as suitable animal waste disinfectants [20,21], despite the concerns about ammonia emissions. A combined treatment could solve this problem with alkalinization to achieve sanitization, followed by neutralization to pH = 7.0 to reduce emissions [22]. The potential negative impacts on soil properties and availability of nutrients to crops induced by the application of slurries with low or high pH values would also be avoided [23].…”

Section: Introductionmentioning

confidence: 99%

Animal Slurry Sanitization through pH Adjustment: Process Optimization and Impact on Slurry Characteristics

et al. 2021

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Sanitization by pH adjustment of dairy and pig slurries was evaluated for potential use as organic fertilizer in horticulture. This requires absence of Salmonella in 25 g of slurry and less than 1000 Escherichi coli colony-forming unit per gram of fresh slurry (Regulation (EU) 2019/1009). Additives used in the alkalinization and acidification treatments, included hydroxide-salts and nitrogen-based reactants to increase slurry pH to a basic range (9.0–11.0) and concentrated H2SO4 to decrease slurry pH to an acidic range (5.5–3.5). While low-cost urea was unable to increase the slurry pH above 9.5, ammonia efficiently increased slurry pH to the targeted values (but enhanced the emissions risk), whereas the effect of Ca(OH)2 was hindered by its low solubility. Slurry sanitization by alkalinization was achieved at a pH of 9.5 for both slurries, using similar quantities of KOH or NaOH. KOH was selected for further tests since it provides a plant macronutrient. Acidification with concentrated H2SO4 was able to achieve sanitization by lowering the pH to 5.0. After a 60-d storage experiment with raw and treated slurries, the level of E. coli was below the sanitization limit for all samples. Storage had no significant impact on slurry characteristics, except for ammonium-nitrogen content. Acidification treatment minimized ammonia losses.

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Section: Introductionmentioning

confidence: 99%

Animal Slurry Sanitization through pH Adjustment: Process Optimization and Impact on Slurry Characteristics

et al. 2021

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“…The alkalization of slurry is another method used to reduce emissions, but it is based on the addition of alkaline additives, that cause the precipitation of phosphorus and an increase in pH, which shifts the equilibrium towards the volatile form NH 3 [14,19]. A so-called stripping technology enables the removal of the growing share of NH 3 in the slurry, which is then captured and concentrated by absorption with concentrated sulphuric acid to produce ammonium-based mineral fertilizers [20,21]. It has been shown that an ammonia recovery rate of more than 90% is possible in cattle slurry at a pH of 12 [20].…”

Section: Introductionmentioning

confidence: 99%

“…A so-called stripping technology enables the removal of the growing share of NH 3 in the slurry, which is then captured and concentrated by absorption with concentrated sulphuric acid to produce ammonium-based mineral fertilizers [20,21]. It has been shown that an ammonia recovery rate of more than 90% is possible in cattle slurry at a pH of 12 [20]. The adjustment of a targeted pH value can be very challenging, as the pH value of stored slurry may fluctuate widely over time due to an increase or decrease in the buffer capacity of the four main buffer systems within slurry, which are volatile fatty acid (VFA) buffer (predominantly CH 3 COOH/CH 3 COO − ), carbonic acid-bicarbonate buffers (H 2 CO 3 / HCO 3 − and HCO 3 − /CO 3 2− , hereafter only HCO 3 and CO 3 2buffer) and ammonia buffer (NH 4 + /NH 3 ) (shown in Figure 1) [22,23].…”

Section: Introductionmentioning

confidence: 99%

Dynamics of Different Buffer Systems in Slurries Based on Time and Temperature of Storage and Their Visualization by a New Mathematical Tool

Overmeyer

Holtkamp

Clemens³

et al. 2020

Animals

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Simple Summary: Efficient slurry management is a key strategy to reduce the release of environmentally harmful gases produced by farm animals. Slurry treatments such as acidification and alkalization have proven to be promising solutions to reduce these emissions. In this context, it is crucial to understand how buffer capacities behave and may influence each other during storage under the influence of different temperatures. To realize this, we have developed and successfully verified a new mathematical tool. It allows an exact calculation and detailed visualization of the most important buffer systems found in the analyzed slurries. This knowledge can be used to optimize slurry treatments, as it allows faster, more precise and efficient timing of pH adjustment, thus, reducing the use of resources.Abstract: Slurry treatments such as acidification and alkalization have proven to be promising solutions to reduce gaseous emission produced by farm animals. The optimization of these technologies requires detailed knowledge of how and to what extent the buffer capacities in slurries will change during storage under the influence of different temperatures, as this may save resources needed to adjust a targeted pH value. Fresh slurries from dairy cows, fattening pigs and sows were collected and stored for 12 weeks under either cold (4.7 ± 1.1 • C) or warm (23.6 ± 2.1 • C) conditions to perform titrations in acidic and alkaline milieu at regular intervals. Based on these results, we successfully verified a new mathematical tool that we have developed to be able to calculate and visualize the most important buffer systems found in the analyzed slurries. Our experimental results showed a strong correlation between the degradation of the volatile fatty acid (VFA) buffer and the emergence of the carbonate buffers, i.e., the HCO 3 − and the CO 3 2− buffer. Furthermore, a drop in the pH value caused by enhanced microbial production of VFAs can be mitigated by the presence of the NH 3 buffer. In conclusion, we demonstrated that the buffers cannot be considered individually but must be interpreted as a complex and interacting system.

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“…Due to its competitive price, H 2 SO 4 is the most commonly used acid during NH 3 washing step. Nevertheless, other agents such as nitric acid, boric acid, organic acids and gypsum have also been tested to recover NH 3 from the gas phase, generating scrubbing salts ( Abouelenien et al, 2009 ; Jamaludin et al, 2018 ; Mohammed-Nour et al, 2019 ; Sigurnjak et al, 2019 ). To our knowledge, Benas is the first AD plant that installed an industrial vacuum NH 3 stripping and scrubbing unit relying on gypsum.…”

Section: Resultsmentioning

confidence: 99%

Techno-economic assessment at full scale of a biogas refinery plant receiving nitrogen rich feedstock and producing renewable energy and biobased fertilisers

Brienza

Sigurnjak

Meier³

et al. 2021

Journal of Cleaner Production

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Anaerobic digestion of nitrogen (N) rich substrates might be hindered when ammonia (NH 3 ) formation reaches toxic levels for methanogenic microorganisms. One possible strategy to avoid inhibiting conditions is the removal of NH 3 from digestate by stripping and scrubbing technology and by recirculating N depleted digestate back to the digester. This study aimed to i) monitor the performance (mass and energy balances) of a full scale digestate processing cascade that includes an innovative vacuum side stream NH 3 stripping and scrubbing system, ii) assess the production cost of ammonium sulphate (AS) solution and iii) evaluate its fertiliser quality. The use of gypsum to recover NH 3 in the scrubbing unit, instead of the more common sulphuric acid, results in the generation of AS and a fertilising liming substrate. Mass and nutrient balances indicated that 57% and 7.5% of ammonium N contained in digestate was recovered in the form of a 22% AS and liming substrate, respectively. The energy balance showed that about 3.8 kWh el and 59 kWh th were necessary to recover 1 kg of N in the form of AS. Furthermore, the production cost of AS, including both capital and operational costs, resulted to be 5.8 € t −1 of digestate processed. According to the fertiliser quality assessment, this technology allows for the recovery of NH 3 in the form of salt solutions that can be utilised as a substitute for synthetic mineral nitrogen fertilisers.

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The Influence of Alkalization and Temperature on Ammonia Recovery from Cow Manure and the Chemical Properties of the Effluents

Cited by 30 publications

References 43 publications

Animal Slurry Sanitization through pH Adjustment: Process Optimization and Impact on Slurry Characteristics

Animal Slurry Sanitization through pH Adjustment: Process Optimization and Impact on Slurry Characteristics

Dynamics of Different Buffer Systems in Slurries Based on Time and Temperature of Storage and Their Visualization by a New Mathematical Tool

Techno-economic assessment at full scale of a biogas refinery plant receiving nitrogen rich feedstock and producing renewable energy and biobased fertilisers

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