Enhancing biomass energy yield from pilot-scale high rate algal ponds with recycling

The viability of Parascaris equorum eggs was studied in two experimental pilot-scale high-rate algal ponds (HRAPs) working in parallel with 4 and 10 days hydraulic retention time respectively. Semi-permeable bags of cellulose (15000 daltons pore size) were used to study the effect of physico-chemical conditions on the survival of these helminth eggs. Three thousand eggs were used in each bag. Replicates of these bags were submerged for 4 and 10 days in the HRAPs and egg viability was compared with that in control bags submerged in sterile water. After 4 days exposure, 60% reduction in viability was achieved, reaching 90% after 10 days, much higher than the 16% and 25% found in the control bags for 4 and 10 days respectively. Ionic conditions of the HRAP may have been responsible for up to 50–60% of the egg mortality, suggesting that mortality due to the ionic environment could be more important than physical retention and other potential removal factors.

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Effect of CO 2 addition on biomass energy yield in wastewater treatment high rate algal mesocosms

Algal Research ◽

10.1016/j.algal.2016.12.010 ◽

2017 ◽

Vol 22 ◽

pp. 93-103 ◽

Cited By ~ 8

Author(s):

Abbas Mehrabadi ◽

Mohammed M. Farid ◽

Rupert Craggs

Keyword(s):

Wastewater Treatment ◽

Biomass Energy ◽

High Rate ◽

Energy Yield

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Nutrient removal in wastewater treatment high rate algal ponds with carbon dioxide addition

Water Science & Technology ◽

10.2166/wst.2011.114 ◽

2011 ◽

Vol 63 (8) ◽

pp. 1758-1764 ◽

Cited By ~ 77

Author(s):

J. B. K. Park ◽

R. J. Craggs

Keyword(s):

Nitrogen Removal ◽

Organic Nitrogen ◽

Inorganic Nitrogen ◽

Nitrogen Loss ◽

Bacterial Biomass ◽

Pilot Scale ◽

High Rate ◽

High Rate Algal Ponds ◽

Carbon Dioxide Addition ◽

Co2 Addition

The influence of CO2 addition to high rate algal ponds (HRAPs) on nitrogen removal was investigated using two pilot-scale HRAPs operated with different hydraulic retention times (HRT: 4 and 8 days), and was compared to the nitrogen removal by the 8-day HRT pond before CO2 addition was installed. Nitrogen balances were calculated by partitioning total nitrogen into organic and inorganic nitrogen (NH+4-N and NO−3-N), and by separation of the organic nitrogen into particulate (PON) and dissolved organic nitrogen (DON). PON was further divided into algal organic nitrogen (AON) and bacteria organic nitrogen (BON) to investigate nitrogen mass flow in the HRAPs. This research shows that the proportion of algae in the algal/bacterial biomass in the longer 8-day HRT HRAP8d (55.6%) was appreciably lower than that in the shorter 4-day HRT HRAP4d (80.5%) when CO2 was added to control the maximum pH to <8.0 during the summer. Higher bacterial biomass in the longer 8-day HRT HRAP corresponded with higher nitrification rates, indicating that the longer 8-day HRT in the summer was detrimental for two reasons: lower algal productivity and increased nitrogen loss through nitrification/denitrification. Overall nitrogen removal of ~60% in the HRAPs with CO2 addition was mainly achieved by algal assimilation followed by sedimentation in the settling unit.

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Effects of two different nutrient loads on microalgal production, nutrient removal and photosynthetic efficiency in pilot-scale wastewater high rate algal ponds

Water Research ◽

10.1016/j.watres.2014.08.010 ◽

2014 ◽

Vol 66 ◽

pp. 53-62 ◽

Cited By ~ 38

Author(s):

Donna L. Sutherland ◽

Matthew H. Turnbull ◽

Paul A. Broady ◽

Rupert J. Craggs

Keyword(s):

Nutrient Removal ◽

Photosynthetic Efficiency ◽

Pilot Scale ◽

High Rate ◽

Nutrient Loads ◽

High Rate Algal Ponds

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Wastewater treatment and algal production in high rate algal ponds with carbon dioxide addition

Water Science & Technology ◽

10.2166/wst.2010.951 ◽

2010 ◽

Vol 61 (3) ◽

pp. 633-639 ◽

Cited By ~ 163

Author(s):

J. B. K. Park ◽

R. J. Craggs

Keyword(s):

Wastewater Treatment ◽

Bacterial Biomass ◽

Pilot Scale ◽

High Rate ◽

Algae Biomass ◽

Algal Production ◽

High Rate Algal Ponds ◽

Gravity Settling ◽

Algal Productivity ◽

Co2 Addition

High rate algal ponds (HRAPs) provide improved wastewater treatment over conventional wastewater stabilisation ponds; however, algal production and recovery of wastewater nutrients as algal biomass is limited by the low carbon:nitrogen ratio of wastewater. This paper investigates the influence of CO2 addition (to augment daytime carbon availability) on wastewater treatment performance and algal production of two pilot-scale HRAPs operated with different hydraulic retention times (4 and 8 days) over a New Zealand Summer (November–March, 07/08). Weekly measurements were made of influent and effluent flow rate and water qualities, algal and bacterial biomass production, and the percentage of algae biomass harvested in gravity settling units. This research shows that the wastewater treatment HRAPs with CO2 addition achieved a mean algal productivity of 16.7 g/m2/d for the HRAP4d (4 d HRT, maximum algae productivity of 24.7 g/m2/d measured in January 08) and 9.0 g/m2/d for the HRAP8d (8 d HRT)). Algae biomass produced in the HRAPs was efficiently harvested by simple gravity settling units (mean harvested algal productivity: 11.5 g/m2/d for the HRAP4d and 7.5 g/m2/d for the HRAP8d respectively). Higher bacterial composition and the larger size of algal/bacterial flocs of the HRAP8d biomass increased harvestability (83%) compared to that of HRAP4d biomass (69%).

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Nutrient removal by the integrated use of high rate algal ponds and macrophyte systems in China

Water Science & Technology ◽

10.2166/wst.2003.0128 ◽

2003 ◽

Vol 48 (2) ◽

pp. 251-257 ◽

Cited By ~ 13

Author(s):

P. Chen ◽

Q. Zhou ◽

J. Paing ◽

H. Le ◽

B. Picot

Keyword(s):

Nutrient Removal ◽

Linear Models ◽

Pilot Scale ◽

High Rate ◽

Temperate Climate ◽

Annual Average ◽

Good Efficiency ◽

Climate Conditions ◽

High Rate Algal Ponds ◽

Nutrient Removal Efficiency

High Rate Algal Ponds (HRAP) were operated at pilot scale to investigate the performance of HRAP under the temperate climate conditions of Shanghai, China. The results indicated that the HRAP gave good efficiency for nutrient removal, especially during summer. With a retention time of 4 or 8d according to the season, the annual average removal efficiencies for COD, NH4-N and PO4-P were 50%, 87% and 40%, respectively. The multi-factor linear models showed the relationships between nutrient removal efficiency and influencing factors. Using a macrophyte pond to separate algae from HRAP can achieve concentrations of COD, TP and TKN in the effluent at around 50 mg/L, 1.5 mg/L and 5 mg/L respectively.

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On-site and in situ bioremediation of wood-preservative contaminated groundwater

Water Science & Technology ◽

10.2166/wst.2000.0537 ◽

2000 ◽

Vol 42 (5-6) ◽

pp. 371-376 ◽

Cited By ~ 11

Author(s):

J.A. Puhakka ◽

K.T. Järvinen ◽

J.H. Langwaldt ◽

E.S. Melin ◽

M.K. Männistö ◽

...

Keyword(s):

Iron Oxidation ◽

Wood Preservative ◽

Pilot Scale ◽

High Rate ◽

Contaminated Groundwater ◽

Groundwater Temperature ◽

In Situ Bioremediation ◽

Contaminated Aquifer ◽

Fluidized Bed Process

This paper reviews ten years of research on on-site and in situ bioremediation of chlorophenol contaminated groundwater. Laboratory experiments on the development of a high-rate, fluidized-bed process resulted in a full-scale, pump-and-treat application which has operated for several years. The system operates at ambient groundwater temperature of 7 to 9°C at 2.7 d hydraulic retention time and chlorophenol removal efficiencies of 98.5 to 99.9%. The microbial ecology studies of the contaminated aquifer revealed a diverse chlorophenol-degrading community. In situ biodegradation of chlorophenols is controlled by oxygen availability, only. Laboratory and pilot-scale experiments showed the potential for in situ aquifer bioremediation with iron oxidation and precipitation as a potential problem.

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