Treatment of Dairy Wastewater using a Low-cost Vermifilter Technology

Primary Author: Gilbert Miito

Faculty Sponsor: Pius Ndegwa

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

Abstract:

The dairy industry generates wastewater streams characterized by high organic and nutrient contents. When discharged untreated, the wastewater streams can lead to several environmental problems which include eutrophication, ground water contamination and greenhouse gas emission. Technologies such as membrane filtration, struvite precipitation, Ammonia stripping, and aerobic treatment have been suggested as viable treatment and recovery options, but these are expensive in terms of resources, labor and energy. Vermifiltration is an emerging low-cost and environmentally sustainable technology for the treatment of wastewater and recovery of nutrients using earthworms. This study evaluated the efficacy of a pilot scale vermifilter at treating a side-stream of dairy wastewater on a commercial dairy. The vermifiltration unit was set up and was monitored for a period of 6 months to study the effect of the process on the chemical oxygen demand, total ammoniacal-nitrogen, orthophosphates, and gas emissions. Influent and effluent samples were collected bi-weekly and analyzed using standardized methods. Gas emissions were also measured on site using the static chamber method. Overall, the vermifilter removed 42% of Chemical Oxygen Demand, 80% of Total Ammoniacal Nitrogen, and 7% of ortho-Phosphates. The vermifilter reduced ammonia emissions by 84–100%, nitrous oxide by 0–59%, carbon dioxide by 58–82% and Methane by 95–99%. These removals are attributed to the synergistic action of earthworms and the microorganisms in the units. Basing on these findings, vermifiltration is a viable low-cost alternative for nutrient recovery and treatment of dairy water while also reducing gaseous emissions.

Sensory Detection of Wine Faults Over Time Using Flash Profiling and the Electronic Tongue

Primary Author: Victoria Minette

Faculty Sponsor: Carolyn Ross

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

Abstract:

Wine faults are negative sensory attributes in wine that may result in large economic losses for wineries and can be attributed to the growth of spoilage microorganisms.  Due to quality changes happening quickly, detection is critical, therefore the use of a rapid sensory profiling method, such as flash profiling, is very useful.  Thus, the objective of this study was to use the electronic tongue (e-tongue) and a rapid sensory method, flash sensory profiling, to evaluate changes in wine over time due to the presence of different spoilage microorganisms.

Merlot wine was bottled and inoculated with different common wine spoilage microorganisms.  Starting at Day 0, wines were analyzed weekly until Day 42 using the e-tongue, microbial plating and flash profiling. PCA, GPA, and AHC analyses were performed.

Over 42 days of storage, both flash profiling and e-tongue analyses differentiated the wines. The e-tongue displayed low discrimination among the different microorganisms through Day 14 of storage. However, at Day 21, the discrimination index increased to 91%, indicating the e-tongue was able to differentiate among the samples.  From the flash profiling data, citations associated with wine faults reached a peak at Day 42 of microbial growth.  As the e-tongue detected differences starting at Day 21, but sensory differences were not apparent until Day 42, these results suggest that the e-tongue is a useful tool for early detection of wine faults.  The application of these novel techniques may be the key to detecting and limiting financial losses associated with wine faults.

Consumer acceptance of a ready-to-eat meal during storage using a home-use test

Primary Author: Maria Montero

Faculty Sponsor: Carolyn Ross

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

Abstract:

A home-use test (HUT) is a method on which a product is consumed in-home under common daily use circumstances. One product that benefits from being evaluated in-home are ready-to-eat meals (RTE). RTE must be processed so they are microbially safe, and a novel method to accomplish this is microwave-assisted-pasteurization (MAPS). Therefore, this study determined consumers’ acceptance of MAPS-processed jambalaya and control through an on-line HUT over a 12-week storage period. Paralleling the HUT, an online auction determined consumers’ willingness to pay. Consumers (n=50) evaluated MAPS-processed jambalaya stored at 2?C and a control (cooked-frozen jambalaya stored at -31oC) after 2, 8 and 12 weeks of storage. Acceptance of different sensory attributes (aroma, appearance, flavor, texture) was measured for both jambalaya samples using an online survey. After tasting, consumers participated in an online auction to bid on the meal they previously sampled- this was used to estimate their willingness to pay for each meal.

Results showed that the processing method (MAPS vs. control) didn’t affect the measured sensory attributes. No significant sensory changes were observed in most of the tested attributes of the jambalaya samples due to storage time; only flavor liking decreased over time. For the online auction, the bid mean values ranged from $3.48-3.74 for the MAPS-processed jambalaya and from $3.33-3.56 for the control, similar to the price of commercially available jambalaya meals. Using a HUT for evaluating consumers’ acceptance of MAPS-processed jambalaya seems like an effective way of testing acceptance of an RTE in a more realistic environment.

The influence of structure locations on wildfire perimeters.

Primary Author: Joshua Olsen

Faculty Sponsor: Jonathan Yoder

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

Abstract:

PRINCIPAL TOPIC

Wildfires suppression in the United States has cost an average of $1.8 billion annually over the past 10 years and wildfire damages have frequently exceeded 10 times that amount. A major reason for the extreme cost of wildfires is the presence of man-made structures.

Despite the large associated cost, the influence that structures have on wildfire spread has yet to be evaluated. We address this gap by analyzing structure density around fire perimeters to understand the relationship between structures and wildfire spread.

METHODS

Using an innovative dataset we evaluate structure presence around wildfires at a finer scale than has previously been possible. We analyze the present of structures per 1,000 acres across a 32 year timespan in the Western United States.

RESULTS/IMPLICATIONS

We find that a disproportionate number of structures reside in a 120 meter bandwidth around fire perimeters. We also find that structure density is highest in the first 30 meters outside of fire perimeters, suggesting that structures are more likely to be found immediately outside fire perimeters than inside fire perimeters. Structure locations are determined prior to fire ignitions which implies that structure locations influence final fire perimeters.

This trend is consistent across all 11 Western United States. This finding has implications for land development policy as well as policies governing prioritization for firefighting resources. For example, our results suggest that current fire suppression is largely guided by the presence of structures. This implies that structure protection may be prioritized over minimizing fire growth.

Influence of increased CO2 on mortality of Varroa destructor during the indoor storage of honey bee (Apis mellifera L.) colonies

Primary Author: Stephen Onayemi

Faculty Sponsor: Brandon Hopkins

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

Abstract:

Indoor storage of honey bee (Apis mellifera L.) colonies during winter months has been practiced in cold climates for decades. Evidence from a recent study showed that conditions during storage could lead to a decrease in the levels of pathogen prevalence in colonies. Varroa is considered one of the most significant threats to colony health and survival, and as such, it is a major contributor to winter mortality and virus transmission in honey bees. An investigation on the effects of increased CO2 on the mortality of Varroa destructor during indoor storage of honey bees was carried out. Eight-frame single deep colonies (n=16) were held in two environmental chambers (both at 4 C) with one set at 8.5% CO2 while the other at normal atmospheric CO2. Each week during the experiment dead/falling mites were collected from the bottom of each colony and counted. At the end of the 62-day experiment, the surviving colonies were treated with a miticide to collect any remaining mites. Mite mortality was calculated by dividing the number of mites collected weekly by the total number of mites collected for each colony. A significant difference in mite mortality was found in colonies held at 8.5% CO2 (73%) in comparison with colonies held at normal atmospheric CO2 (51%). This study demonstrates that increased CO2 during an indoor storage period could increase mite mortality and in turn, reduce virus transmission and improve honey bee health coming out of the winter months.

Performance evaluation of high barrier metal-oxide coated polymeric films intended for in-package thermally sterilized food products

Primary Author: Ashutos Parhi

Faculty Sponsor: Shyam Sablani

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

Abstract:

Principal Topic

Metal-oxide coated multilayered polyethylene terephthalate (PET) films are used for storing in-package thermally processed food products. However, these films can develop defects when exposed to retort and microwave assisted thermal sterilization (MATS) processes. This increases their oxygen and water vapor transmission rates (OTRs,WVTRs) reducing the shelf life of packaged food.

Method

In this work, we evaluated four film pouches: MOA, MOC, MOE, MOF having layers of metal-oxide coated PET, Nylon 6 and polypropylene. We filled them with water and processed in a retort at 121°C (F0=6–9 min) and MATS at 124°C (F0=10.9 min). The processing times were determined based on solid food products packaged in flexible pouches. Subsequently, the pouches were emptied, dried, filled with an oxygen-sensitive gel, resealed and stored at 23°C for 180-days. The gel changed color at locations with defects and we extracted samples from those locations for scanning electron and confocal laser scanning microscopies (SEM, CLSM).

Results

OTRs and WVTRs of the films increased significantly (P<0.05) after thermal processing with MOA showing the highest increase and MOF the least. Presence of additional layers of coating may have reduced the barrier deterioration in MOF pouches. MATS processed films showed a lower change compared to retort process. MOC, MOE and MOF pouches showed fewer defects than MOA, visualized through localized color change in the packaged gel as well as SEM and CLSM analysis. Overall, the MOF pouches showed least deterioration after thermal processing and will be ideal for shelf-stable food products with an extended shelf-life.