Anaerobic digestion of liquid dairy manure pretreated by the microwave-enhanced advanced oxidation process.

The microwave-enhanced advanced oxidation process (MW-AOP) was utilized for the treatment of liquid dairy manure, prior to anaerobic digestion (AD). A significant amount of soluble chemical oxygen demand (SCOD) was formed in the treated solution, but there was no or little increase in volatile fatty acid (VFA). In this study, up-flow anaerobic sludge blanket (UASB) reactors were used in both the conventional AD system and as the methane phase reactor in a two-phase anaerobic digestion (TPAD) system.

Evaluation of impact of sludge types and solids content on sludge treatment using microwave enhanced advanced oxidation process.

The microwave enhanced advanced oxidation process (MW-AOP) has been applied to pre-treat different sludge types and high solids content. Secondary sludge not only had the highest solids and nutrient content but also yielded higher treatment efficiency than primary or mixed sludge. In the case of secondary sludge with 4% total solids (TS), the total suspended solids (TSS) concentration was reduced by 32% while soluble chemical oxygen demand concentration increased from 1% to 40% after treatment at 110°C.

Microwave enhanced advanced oxidation treatment of fat, oil and grease (FOG) with organic co-substrates.

Mixtures of fats, oils and grease (FOG) either with dairy manure or with thickened waste secondary sludge (TWSS) were treated using microwave enhanced advanced oxidation process (MW-AOP). For both dairy manure and TWSS mixtures, the maximum increase in soluble COD (SCOD) resulted from the 1:1 mixture by total solids (TS) weight. In the TWSS mixtures, production of volatile fatty acid (VFA) increased with greater FOG content, while there was a decreasing production trend in VFA in dairy manure mixtures.

Microwave enhanced oxidation treatment of organic fertilizers.

Background: Liquid organic fertilizers (LOFs) are relatively easier to degrade than those of solid organic fertilizers, and the nutrients are readily available for plant uptake. Microwave enhanced advanced oxidation treatment (MW/H O -AOP) was used to convert solid organic fertilizers (insoluble blood meal, bone meal, feather meal, sunflower ash and a mixture) into LOF.

Results: After the MW/H O -AOP treatment, high soluble nitrogen (11-29%), soluble phosphorus (64%) and potassium (92%), as well as low total suspended solids content could be obtained.

Microwave treatment of dairy manure for resource recovery: Reaction kinetics and energy analysis.

A newly designed continuous-flow 915 MHz microwave wastewater treatment system was used to demonstrate the effectiveness of the microwave enhanced advanced oxidation process (MW/HO-AOP) for treating dairy manure. After the treatment, about 84% of total phosphorus and 45% of total chemical oxygen demand were solubilized with the highest HO dosage (0.4% HO per %TS).

Treatment of sewage sludge in a continuous-flow radiofrequency-oxidation system.

This study explored the applicability of a pilot-scale continuous-flow radiofrequency (RF) heating system to treat sewage sludge by the RF-oxidation process (RF/HO). Depending on temperature and hydrogen peroxide dosage, high amounts of soluble chemical oxygen demand and volatile fatty acid were produced, and phosphates, nitrogen, and metals were solubilized. A high temperature and/or a higher HO dosage implemented in this system yielded high solubilization of organic matters.

Radiofrequency-oxidation treatment of sewage sludge.

A novel thermal-chemical treatment technology using radiofrequency heating and oxidants (hydrogen peroxide, ozone and a combination of both) was used for the treatment of sewage sludge. This was to evaluate the process effectiveness on cell disintegration and nutrient release of sludge, physical property changes such as particle size distribution, dewaterability and settleability, and their inter-relationships. The effectiveness of treatment processes was in the following order, from the most to least: thermal-oxidation process, oxidation process and thermal process.

Microwave oxidation treatment of sewage sludge.

Microwave-oxidation treatment of sewage sludge using various oxidants was studied. Two treatment schemes with a combination of hydrogen peroxide and ozone were examined: hydrogen peroxide and ozone were introduced into the sludge simultaneously, followed by microwave heating. The other involved the ozonation first, and then the resulting solution was subjected to microwave and hydrogen peroxide treatment.

Recovery of phosphorus from dairy manure: a pilot-scale study.

Phosphorus was recovered from dairy manure via a microwave-enhanced advanced oxidation process (MW/H2O2-AOP) followed by struvite crystallization in a pilot-scale continuous flow operation. Soluble phosphorus in dairy manure increased by over 50% after the MW/H2O2-AOP, and the settleability of suspended solids was greatly improved. More than 50% of clear supernatant was obtained after microwave treatment, and the maximum volume of supernatant was obtained at a hydrogen peroxide dosage of 0.

Effects of acidifying reagents on microwave treatment of dairy manure.

Dairy manure, acidified using organic acids (acetic, oxalic, and citric acid) were treated with microwave enhanced advanced oxidation process (MW/H2O2-AOP). The effect of a mixture of oxalic acid and commonly used mineral acids (sulfuric and hydrochloric acid) on MW/H2O2-AOP was also examined. Substantial amounts of phosphorus were released under MW/H2O2-AOP, regardless of organic acid or mineral acid used.

Microwave enhanced advanced oxidation process for treating dairy manure at low pH.

This study investigated the treatment of dairy manure using the microwave enhanced advanced oxidation process (MW-AOP) at pH 2. An experimental design was developed based on a statistical program using response surface methodology to explore the effects of temperature, hydrogen peroxide dosage and heating time on sugar production, nutrient release and solids destruction. Temperature, hydrogen peroxide dosage and acid concentration were key factors affecting reducing sugar production.

Treatment of dairy manure using the microwave enhanced advanced oxidation process under a continuous mode operation.

The microwave enhanced advanced oxidation process (MW/H(2)O(2)-AOP) was used to treat dairy manure for solubilization of nutrients and organic matters. This study investigated the effectiveness of the MW/H(2)O(2)-AOP under a continuous mode of operation, and compared the results to those of batch operations. The main factors affecting solubilization by the MW/H(2)O(2)-AOP were heating temperature and hydrogen peroxide dosage.

Nutrient release from extracted activated sludge cells using the microwave enhanced advanced oxidation process.

This study investigates the effectiveness of the microwave enhanced advanced oxidation process (MW/H(2)O(2)-AOP) for nutrient release and cell destruction of the extracted activated sludge cells that are EPS-free. The concentrations of ammonia and soluble chemical oxygen demand increased with an increase of microwave temperature and hydrogen peroxide dosage. Orthophosphate could be released from these extracted cells at lower microwave temperatures and lower H(2)O(2) dosages compared to our previous studies using activated sludge.

The effects of irradiation intensity on the microwave-enhanced advanced oxidation process.

The microwave enhanced advanced oxidation process (MW/H(2)O(2)-AOP) was adopted in successfully treating a multitude of organic slurries. The factor of ramp rate was incorporated in this study to investigate its correlations with different nutrients release into solution from waste activated sludge. Besides the ramp rate, the amount of time the samples were held at the treatment temperature to a total of 10 minutes aided in the isolation of held temperature from ramp rates, since different ramp rates will yield different reaction times.

Treating solid dairy manure using microwave-enhanced advanced oxidation process.

The microwave enhanced advanced oxidation process (MW/H(2)O(2)-AOP) was used to treat separated solid dairy manure for nutrient release and solids reduction. The MW/H(2)O(2)-AOP was conducted at a microwave temperature of 120 degrees C for 10 minutes, and at three pH conditions of 3.5, 7.

Factors affecting microwave-enhanced advanced oxidation process for sewage sludge treatment.

The microwave-enhanced advanced oxidation process (MW/H(2)O(2)-AOP) was applied to sewage sludge for nutrient solubilization and solids' disintegration. Four factors, temperature, hydrogen peroxide dosage, mixing, and solids concentration were chosen for a screening experiment, and were ranked according to their significance of influence on the process. In general, temperature and hydrogen peroxide dosage are the two significant factors affecting the process, while mixing is the least significant factor.

Solubilization of municipal anaerobic sludge using microwave-enhanced advanced oxidation process.

The effect of microwave enhanced advanced oxidation process on the release of nutrients and solids disintegration from municipal anaerobic sludge was investigated. Three levels of temperature (160, 120, and 80 degrees C) and two sets of pH, (7.8 and 4) were selected and tested at a microwave heating time of 5 minutes and hydrogen peroxide dosage of approximately 1 mL per 1% total solids.

Nutrient release from fish silage using microwave-enhanced advanced oxidation process.

The microwave-enhanced advanced oxidation process was used to treat fish silage for nutrient release and solids reduction prior to its use as a fertilizer for greenhouse operations. Fifteen sets of experiments with varying hydrogen peroxide dosages and treatment temperatures were conducted to evaluate the effectiveness of the process on the solubilization of fertilizer constituents. It was found that up to 26% of total Kjeldahl nitrogen could be released as ammonia with 6% hydrogen peroxide dosage at 170 degrees C.

Role of mixing on microwave-enhanced advanced oxidation process in treating sewage sludge.

The microwave enhanced advanced oxidation process (MW/H2O2-AOP) was used for the release of nutrients and the disintegration of suspended solids from both anaerobic sludge and aerobic sludge. The purpose of this study was to determine the effects of mixing on the performance of the process, in terms of soluble ammonia, orthophosphate and soluble chemical oxygen demands. Experiments were conducted on sludge samples with various total solids concentrations (1.

Microwave treatment and struvite recovery potential of dairy manure.

Microwave digestion of liquid dairy manure was tested for the release of nutrients, such as orthophosphates, ammonia-nitrogen, magnesium, calcium and potassium, both with and without the aid of an oxidizing agent (hydrogen peroxide). The orthophosphate to total phosphorus ratio of the manure increased from 21% to greater than 80% with 5 minutes of microwave treatment. More than 36% of total chemical oxygen demand (t-COD) of the manure was reduced when microwave digestion was assisted with peroxide addition.

Sewage sludge treatment using microwave-enhanced advanced oxidation process.

A microwave-enhanced advanced oxidation process using hydrogen peroxide (MW/H(2)O(2)-AOP) was used for the release of nutrients and the destruction of solids from secondary municipal sewage sludge in this study. Using a computer statistical software package for designing experiments and for data analyses, four factors including microwave heating temperature, heating time, hydrogen peroxide dosage, and sludge solids content were examined. Experiments were performed at sludge solids content of 0.

An ozone/hydrogen peroxide/microwave-enhanced advanced oxidation process for sewage sludge treatment.

Solids destruction and nutrients release from sewage sludge were investigated using thermal destruction and/or oxidation processes. Hydrogen peroxide (H(2)O(2)), ozone (O(3)) and a combination of both were used for the oxidation processes performed at ambient temperature. Thermal destruction using microwave (MW) alone without an oxidant was also conducted.

Solubilization of blood meal to be used as a liquid fertilizer.

The solubilization of blood meal by means of the microwave-hydrogen peroxide enhanced advanced-oxidation process (MW/H(2)O(2)-AOP) was studied. It was found that over the treatment temperature range of 60 to 120 degrees C, solids particle reduction, ammonia and orthophosphate production could be achieved by this process. Large protein molecules were broken down into intermediate compounds with low molecule weights, ammonia and nitrate.

Factors affecting nutrient solubilization from sewage sludge using microwave-enhanced advanced oxidation process.

A microwave-enhanced advanced oxidation process using hydrogen peroxide (MW-H2O2-AOP) was used for the solubilization of phosphate and ammonia from secondary municipal sludge. Two sets of experiments were performed to determine the factors affecting nutrient solubilization from sewage sludge. Four factors--microwave heating temperature, heating time, hydrogen peroxide treatment, and sulphuric acid treatment--were incorporated into a screening design to determine which factors were significant for maximizing nutrient solubilization.

Real-time treatment of dairy manure: implications of oxidation reduction potential regimes to nutrient management strategies.

A pilot-scale sequencing batch reactor (SBR) was operated at a dairy farm to test real-time based control in winter operation conditions. A combination of high loading and low oxidation reduction potential (ORP) conditions in the aerobic stage of SBR treatment (an end value of -50 to -150 mV) inhibited nitrification while maintaining carbon removal. After a period of over-aeration over several cycles, the ORP at the end of the aerobic stage increased to values of 50-75 mV.