Algal-bacterial shortcut nitrogen removal model with seasonal light variations.

The algal-bacterial shortcut nitrogen removal (ABSNR) process can be used to treat high ammonia strength wastewaters without external aeration. However, prior algal-bacterial SNR studies have been conducted under fixed light/dark periods that were not representative of natural light conditions. In this study, laboratory-scale photo-sequencing batch reactors (PSBRs) were used to treat anaerobic digester sidestream under varying light intensities that mimicked summer and winter conditions in Tampa, FL, USA.

Autotrophic denitrification supported by sphalerite and oyster shells: Chemical and microbiome analysis.

This research evaluated the metal-sulfide mineral, sphalerite, as an electron donor for autotrophic denitrification, with and without oyster shells (OS). Batch reactors containing sphalerite simultaneously removed NO and PO from groundwater. OS addition minimized NO accumulation and removed 100% PO in approximately half the time compared with sphalerite alone.

Water quality and hydraulic performance of biochar amended biofilters for management of agricultural runoff.

This research evaluated the effect of biochar amendment rate on nitrogen species and organic carbon removals and hydraulic performance in biofilter columns treating dairy farm runoff. Initial studies compared the performance of sand columns amended with two types of biochar with different specific surface area (SA) and cation exchange capacity (CEC) with an un-amended sand column. The results showed that biochar enhanced N-species removal due to its unique physicochemical properties.

Wood and sulfur-based cyclic denitrification filters for treatment of saline wastewaters.

This study investigated the performance and microbiome of cyclic denitrification filters (CDFs) for wood and sulfur heterotrophic-autotrophic denitrification (WSHAD) of saline wastewater. Wood-sulfur CDFs integrated into two pilot-scale marine recirculating aquaculture systems achieved high denitrification rates (103 ± 8.5 g N/(m·d)).

Degenerate PCR primers for assays to track steps of nitrogen metabolism by taxonomically diverse microorganisms in a variety of environments.

Steps in the global nitrogen cycle are mainly catalyzed by microorganisms. Accordingly, the activities of these microorganisms affect the health and productivity of ecosystems. Their activities are also used in wastewater treatment systems to remove reactive nitrogen compounds and prevent eutrophication events triggered by nutrient discharges.

A sulfur-based cyclic denitrification filter for marine recirculating aquaculture systems.

Nitrogen removal from saline wastewater is challenging due to adverse effects of salinity on biological processes. A novel sulfur-autotrophic cyclic denitrification filter (CDF) was tested for marine recirculating aquaculture systems (RAS) under varying conditions. Low ammonia, nitrite and sulfide concentrations were maintained at residence times between 4 and 12 h.

Biochar amendment of stormwater bioretention systems for nitrogen and Escherichia coli removal: Effect of hydraulic loading rates and antecedent dry periods.

Bioretention systems improve stormwater infiltration and water quality; however, limited total nitrogen (TN) and fecal indicator bacteria (FIB) removal is observed in sand-based bioretention media. In this study, the fate of nitrogen and E. coli in bioretention systems was investigated through batch and column studies using sand media, with and without biochar addition.

Comparative environmental and economic life cycle assessment of high solids anaerobic co-digestion for biosolids and organic waste management.

High-Solids Anaerobic co-Digestion (HS-AcD) of sewage sludge (biosolids) with the organic fraction of municipal solid waste is a promising waste management alternative due to high methane yields, lower reactor volume requirements, lower energy inputs, and less leachate production than liquid anaerobic digestion. This study evaluated the environmental and economic burdens and benefits of HS-AcD of biosolids, Food Waste (FW), and Yard Waste (YW) using Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) methods using Hillsborough County, Florida in the U.S.

Long-term field performance of a conventional and modified bioretention system for removing dissolved nitrogen species in stormwater runoff.

Bioretention systems are efficient at removing particulates, metals, and hydrocarbons from stormwater runoff. However, managing dissolved nitrogen (N) species (dissolved organic N, NH, NO, NO) is a challenge for these systems. This paper reports the results of a long-term field study comparing N removal of: 1) a modified bioretention system that included an internal water storage zone containing wood chips to promote denitrification and 2) a conventional bioretention system.

Mass fluxes of nitrogen and phosphorus through water reclamation facilities: Case study of biological nutrient removal, aerobic sludge digestion, and sidestream recycle.

At water reclamation facilities, recycling of nutrients (nitrogen and phosphorus) from solids-handling processes to the mainstream treatment process can have detrimental effects on biological nutrient removal systems. In this study, mass fluxes of nitrogen and phosphorus were quantified through the treatment trains at the Northwest Regional Water Reclamation Facility (NWRWRF) and the adjoining Biosolids Management Facility (BMF), which receives sludge from several water reclamation facilities in Hillsborough County, Florida. The driving objectives were to determine (a) whether the return stream from BMF to NWRWRF (i.

Biogas production from high solids anaerobic co-digestion of food waste, yard waste and waste activated sludge.

High-solids anaerobic co-digestion (HS-AcD) has the potential to recover energy and reduce environmental impacts of the organic fraction of municipal solid waste and waste activated sludge. We investigated the impact of substrate to inoculum (S/I) ratios, alkalinity sources (sodium bicarbonate and oyster shells), co-substrate mixing ratios and inoculum acclimation on HS-AcD of food waste, yard waste, and waste activated sludge using batch studies. Long-term HS-AcD performance was evaluated under the optimal conditions through a semi-continuous biodigester study with leachate recirculation.

Hybrid algal photosynthesis and ion exchange (HAPIX) process for high ammonium strength wastewater treatment.

A hybrid algal photosynthesis and ion exchange (HAPIX) process was developed that uses natural zeolite (chabazite) and wild type algae to treat high ammonium (NH) strength wastewater. In the HAPIX process, NH is temporarily adsorbed from the liquid, which reduces the free ammonia (FA) concentration below the inhibitory level for algal growth. The slow release of adsorbed NH subsequently supports the continuous growth of algae.

Biological denitrification in marine aquaculture systems: A multiple electron donor microcosm study.

There is a lack of information on denitrification of saline wastewaters, such as those from marine recirculating aquaculture systems (RAS), ion exchange brines and wastewater in areas where sea water is used for toilet flushing. In this study, side-by-side microcosms were used to compare methanol, fish waste (FW), wood chips, elemental sulfur (S) and a combination of wood chips and sulfur for saline wastewater denitrification. The highest denitrification rate was obtained with methanol (23.

Advances in algal-prokaryotic wastewater treatment: A review of nitrogen transformations, reactor configurations and molecular tools.

The synergistic activity of algae and prokaryotic microorganisms can be used to improve the efficiency of biological wastewater treatment, particularly with regards to nitrogen removal. For example, algae can provide oxygen through photosynthesis needed for aerobic degradation of organic carbon and nitrification and harvested algal-prokaryotic biomass can be used to produce high value chemicals or biogas. Algal-prokaryotic consortia have been used to treat wastewater in different types of reactors, including waste stabilization ponds, high rate algal ponds and closed photobioreactors.

Bioregeneration of Chabazite During Nitrification of Centrate from Anaerobically Digested Livestock Waste: Experimental and Modeling Studies.

Nitrification of high total ammonia nitrogen-strength wastewaters is challenging due to free ammonia (FA) inhibition of nitrification. FA inhibition can potentially be alleviated by temporarily adsorbing ammonium (NH) to natural zeolite, such as chabazite, followed by direct zeolite bioregeneration via nitrification. In this research, the effectiveness of chabazite addition for reducing nitrification inhibition during treatment of centrate from anaerobic digestion of swine waste was quantified.

Cost-effective treatment of swine wastes through recovery of energy and nutrients.

Wastes from concentrated animal feeding operations (CAFOs) are challenging to treat because they are high in organic matter and nutrients. Conventional swine waste treatment options in the U.S.

Effect of oyster shell medium and organic substrate on the performance of a particulate pyrite autotrophic denitrification (PPAD) process.

The use of pyrite as an electron donor for biological denitrification has the potential to reduce alkalinity consumption and sulfate by-product production compared with sulfur oxidizing denitrification. This research investigated the effects of oyster shell and organic substrate addition on the performance of a particulate pyrite autotrophic denitrification (PPAD) process. Side-by-side bench-scale studies were carried out in upflow packed bed bioreactors with pyrite and sand, with and without oyster shells as an alkalinity source.

Modelling shortcut nitrogen removal from wastewater using an algal-bacterial consortium.

A shortcut nitrogen removal process was investigated for treatment of high ammonium strength wastewater using an algal-bacterial consortium in photo-sequencing batch reactors (PSBRs). In this process, algae provide oxygen for nitritation during the light period, while denitritation takes place during the dark (anoxic) period, reducing overall energy and chemical requirements. Two PSBRs were operated at different solids retention times (SRTs) and fed with a high ammonium concentration wastewater (264 mg NH-N L), with a '12 hour on, 12 hour off' light cycle, and an average surface light intensity of 84 μmol m s.

Comparison of particulate pyrite autotrophic denitrification (PPAD) and sulfur oxidizing denitrification (SOD) for treatment of nitrified wastewater.

The use of reduced sulfur compounds as electron donors for biological denitrification has the potential to reduce chemical and sludge disposal costs as well as carry-over of organic carbon to the effluent that often occurs with heterotrophic denitrification. Although a number of prior studies have evaluated sulfur oxidizing denitrification (SOD), no prior studies have evaluated particulate pyrite autotrophic denitrification (PPAD) in continuous flow systems. Bench-scale upflow packed bed reactors (PBRs) were set up to compare denitrification rates, by-product production and alkalinity consumption of PPAD and SOD.

Does the use of tubular digesters to treat livestock waste lower the risk of infection from Cryptosporidium parvum and Giardia lamblia?

Worldwide, high incidences of cryptosporidiosis and giardiasis are attributed to livestock waste. Quantitative microbial risk assessment can be used to estimate the risk of livestock related infections from Cryptosporidium parvum and Giardia lamblia. The objective of this paper was to assess the occupational and public health risks associated with management of raw and anaerobically digested livestock waste in two rural communities in Costa Rica based on fomite, soil and crop contamination and livestock waste management exposure pathways.

Viability and fate of Cryptosporidium parvum and Giardia lamblia in tubular anaerobic digesters.

In many developing countries where pathogenic diseases of animal waste origin, such as giardiasis and cryptosporidiosis, are often prevalent, facilities are limited to treat livestock waste. However, household-scale anaerobic digesters are currently being promoted for bioenergy production from livestock manure. Since the effluent is often used as a fertilizer for food crops, it is critical to understand the effect of environmental conditions within household-scale digesters on the viability of Cryptosporidium parvum oocysts and Giardia lamblia cysts.

A novel shortcut nitrogen removal process using an algal-bacterial consortium in a photo-sequencing batch reactor (PSBR).

Removal of nitrogen from anaerobically digested swine manure centrate was investigated in a photo-sequencing batch reactor (PSBR) with alternating light and dark periods. Microalgal photosynthesis was shown to provide enough oxygen for complete nitritation during the light period. With addition of an organic carbon source during the dark period, the reactor removed over 90% total nitrogen (TN) without aeration other than by mixing.

Semi-continuous mesophilic anaerobic digester performance under variations in solids retention time and feeding frequency.

The goal of this research was to understand the effect of solids retention time (SRT) and feeding frequency on the performance of anaerobic digesters used to recover bioenergy from swine waste. Semi-continuous mesophilic anaerobic digesters were operated at varying SRTs and feeding frequencies. Performance metrics included biogas and methane production rates, biomass robustness and functionality and removals of volatile solids, soluble chemical oxygen demand, the fecal-indicator bacteria Escherichia coli, and the human pathogen Salmonella.

Assessing the fate of Ascaris suum ova during mesophilic anaerobic digestion.

There is limited knowledge about the survival of geohelminths, which are soil-transmitted human pathogens, in mesophilic anaerobic digestion processes. This study examined the fate of embryonated and unembryonated Ascaris suum ova in six laboratory-scale mesophilic (35 °C) anaerobic digesters processing swine manure to identify their survival strategies and investigate potential mechanisms to enhance their destruction. There was no significant difference in inactivation of Ascaris suum ova in digesters operated at different solids residence times (SRT) or feeding frequencies.

A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process for decentralized wastewater treatment.

Nitrogen discharges from decentralized wastewater treatment (DWT) systems contribute to surface and groundwater contamination. However, the high variability in loading rates, long idle periods and lack of regular maintenance presents a challenge for biological nitrogen removal in DWT. A Tire-Sulfur Hybrid Adsorption Denitrification (T-SHAD) process was developed that combines nitrate (NO3(-)) adsorption to scrap tire chips with sulfur-oxidizing denitrification.