Impact of Feeding Activity of Silver Carp on Plankton Removal from a High-Rate Pond Effluent

2005 ◽  
Vol 40 (2) ◽  
pp. 191-201 ◽  
Author(s):  
Nadia Berday ◽  
Driss Zaoui ◽  
Abdeljaouad Lamrini ◽  
Mustapha Abi
Keyword(s):  
Feeding Activity ◽  
Silver Carp ◽  
Treatment Plant ◽  
High Rate ◽  
Fish Pond ◽  
Gut Contents ◽  
Hypophthalmichthys Molitrix ◽  
Technology System ◽  
Solids Concentration ◽  
Plankton Communities

Abstract The effect of silver carp (Hypophthalmichthys molitrix Val.) feeding activity on the plankton communities in a high-rate pond technology system (HRPTS) effluent was investigated over a period of 100 days. The experiment was conducted at the experimental wastewater treatment plant of the Agronomic and Veterinary Medicine Institute (AVI) of Rabat, Morocco, using a HRPTS in a fish pond receiving the plant effluent. The effluent was highly dominated by phytoplankton (99.95%). Silver carp could survive and grow in the fish pond. Production was 37 kg with a very low mortality rate (12%). The high specific intestine weight (7%) and intake rates of biomass and phytoplankton by silver carp (616 g kg-1 of fish day-1 and 1.6 x 1011 cell kg-1 of fish day-1, respectively) demonstrated the importance of the feeding activity of the fish. Zooplankton intake rates were lower (2 x 107 bodies kg-1 of fish day-1). The high intestine index (3 to 4.3 for fish sizes of 14 to 22 cm) and the dominance of phytoplankton in the gut contents (99.95%) confirmed an omnivorous/ phytoplanctivorous diet. Silver carp were efficient in removing plankton from the HRPTS effluent. The net removal yields of biomass were 285 g m-3 day-1 and 322 g kg-1 of fish day-1, 7 x 1010 algal cells kg-1 of fish day-1 and 8.7 x 107 zooplankton bodies kg-1 of fish day-1, with net removal rates of 47, 64 and 62%, respectively. The total suspended solids concentration decreased from 211 in the inflow to 112 mg L-1 in the fish pond.

Comparison of high-throughput sequencing analysis of gut contents between silver carp Hypophthalmichthys molitrix and bighead carp Hypophthalmichthys nobilis in mesotrophic and eutrophic lakes

2020 ◽  
Vol 71 (7) ◽  
pp. 761
Author(s):  
Chaoqun Su ◽  
Wenjing Hu ◽  
Zhongjun Hu ◽  
Zhen Zhang ◽  
Oranich Wedchaparn ◽  
...  
Keyword(s):  
High Throughput ◽  
High Throughput Sequencing ◽  
Lake Taihu ◽  
Silver Carp ◽  
Bighead Carp ◽  
Gut Contents ◽  
Sequencing Analysis ◽  
Hypophthalmichthys Molitrix ◽  
Eutrophic Lakes ◽  
Hypophthalmichthys Nobilis

High-throughput sequencing analysis of gut contents was used to study the feeding habits of two filter-feeding fish, namely silver carp Hypophthalmichthys molitrix and bighead carp Hypophthalmichthys nobilis, in mesotrophic Lake Qiandao and eutrophic Lake Taihu. Silver carp feed primarily on phytoplankton, with a feeding preference for Chlorophyta, in Lake Qiandao and rely on phytoplankton in Lake Taihu. Bighead carp feed more on zooplankton in Lake Qiandao and on phytoplankton in Lake Taihu. With increasing levels of algae, bighead carp feed more on phytoplankton. The dietary shifts suggest that bighead carp would be useful in controlling nuisance algae in lakes.

A Novel Approach to Evaluate Feeding by Mixed Cyprinid Species in a Chinese Integrated Fish Culture Pond Using Measurements of Chlorophyll Derivatives and Photosynthesis in Gut Contents

1993 ◽  
Vol 50 (5) ◽  
pp. 946-952 ◽  
Author(s):  
Noriko Takamura ◽  
Ja-Le Li ◽  
He-Quan Yang ◽  
Xue-Bao Zhu ◽  
Taizo Miura
Keyword(s):  
Aquatic Plants ◽  
Silver Carp ◽  
Fish Culture ◽  
Ctenopharyngodon Idella ◽  
Gut Contents ◽  
Hypophthalmichthys Molitrix ◽  
Pigment Analysis ◽  
Chl A ◽  
Cyprinid Species ◽  
Chlorophyll Derivatives

Chlorophyll derivatives and algal photosynthesis in the guts of five reared cyprinid species were studied to quantify feeding by cyprinids in a Chinese integrated fish culture pond. Pigment analysis identified organic detritus that had been overlooked by microscopic observation. The high ratios of Chl b/Chl a and of pheophorbide a/Chl a were good indicators of herbivory on aquatic plants and zooplanktivory, respectively. High photosynthetic rates in faeces indicated herbivory on phytoplankton. Grass carp (Ctenopharyngodon idella) fed mostly on aquatic plants. Blunt snout bream (Megalobrama amblyocephala) selected plants, but also fed on filamentous algae and zooplankton. Silver carp (Hypophthalmichthys molitrix) fed on phytoplankton most frequently among the five carp species examined, but also utilized zooplankton and amorphous detritus, probably originating from plant fragments. Bighead (Aristichthys nobilis) and crucian carp (Carassius auratus) utilized zooplankton and plant fragments. Planktivorous production in this pond was partly supported by a large amount of plant debris, derived from the faeces of grass-eating cyprinids and nourished by microorganisms in the pond water.

Escherichia coli Contamination of Fish Raised in Integrated Pig-Fish Aquaculture Systems in Vietnam

2012 ◽  
Vol 75 (7) ◽  
pp. 1317-1319 ◽  
Author(s):  
SON THI THANH DANG ◽  
ANDERS DALSGAARD
Keyword(s):  
Escherichia Coli ◽  
Muscle Tissue ◽  
Grass Carp ◽  
Silver Carp ◽  
Fecal Contamination ◽  
Fish Muscle ◽  
Gut Contents ◽  
Pig Manure ◽  
Hypophthalmichthys Molitrix ◽  
E Coli

Integrated livestock-fish aquaculture utilizes animal excreta and urine as pond fertilizers to enhance growth of plankton and other microorganisms eaten by the fish. In Vietnam, pigs are commonly integrated with fish and horticulture in household-based VAC systems (vuon = garden; ao = pond; chuong = pigsty), but the level of fecal contamination in the fish produced is unknown. This study was carried out to assess the level Escherichia coli contamination of fish meat and gut contents of grass carp (Ctenopharyngodon idellus), silver carp (Hypophthalmichthys molitrix), and rohu (Labeo rohita) cultured in randomly selected five VAC ponds (with pig manure) and five non-VAC ponds (without pig manure) at sites in periurban Hanoi, Vietnam. Fish muscle tissue samples contained E. coli at <10 or 320 or 820 CFU/g, regardless of the culture system from which they originated. In contrast, the intestinal contents of fish raised in manure-fed ponds contained E. coli at 4.75, 5.25, and 5.07 log CFU/g for silver carp, grass carp, and rohu, respectively, about 100 times higher than the contamination of fish from the control ponds. The results indicate that muscle tissue of fish raised in VAC systems has a low level of fecal contamination despite high levels of E. coli in their gut. Thus, a critical point to control food safety of such fish is the prevention of fecal cross-contamination during degutting and cleaning of the fish at markets and in the home.

Rehabilitation and Upgrading of the Beni Suef City Wastewater Treatment Plant

1990 ◽  
Vol 22 (7-8) ◽  
pp. 131-138
Author(s):  
Ahmed Fadel
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Primary Treatment ◽  
High Rate ◽  
Shock Load ◽  
Economic Evaluations ◽  
Activated Sludge Process ◽  
Trickling Filter

Many of Egypt's cities have existing treatment plants under operation that have been constructed before 1970. Almost all of these treatment plants now need rehabilitation and upgrading to extend their services for a longer period. One of these plants is the Beni Suef City Wastewater Treatment Plant. The Beni Suef WWTP was constructed in 1956. It has primary treatment followed by secondary treatment employing intermediate rate trickling filters. The BOD, COD, and SS concentration levels are relatively high. They are approximately 800, 1100, and 600 mg/litre, respectively. The Beni Suef city required the determination of the level of work needed for the rehabilitation and upgrading of the existing 200 l/s plant and to extend its capacity to 440 l/s at year 2000 A description of the existing units, their deficiencies and operation problems, and the required rehabilitation are presented and discussed in this paper. Major problems facing the upgrading were the lack of space for expansion and the shortage of funds. It was, therefore, necessary to study several alternative solutions and methods of treatment. The choice of alternatives was from one of the following schemes: a) changing the filter medium, its mode of operation and increasing the number of units, b) changing the trickling filter to high rate and combining it with the activated sludge process, for operation by one of several possible combinations such as: trickling filter-solids contact, roughing filter-activated sludge, and trickling filter-activated sludge process, c) dividing the flow into two parts, the first part to be treated using the existing system and the second part to be treated by activated sludge process, and d) expanding the existing system by increasing the numbers of the different process units. The selection of the alternative was based on technical, operational and economic evaluations. The different alternatives were compared on the basis of system costs, shock load handling, treatment plant operation and predicted effluent quality. The flow schemes for the alternatives are presented. The methodology of selecting the best alternative is discussed. From the study it was concluded that the first alternative is the most reliable from the point of view of costs, handling shock load, and operation.

High rate and compact single sludge pre-denitrification process for retrofit

1994 ◽  
Vol 30 (6) ◽  
pp. 31-40 ◽  
Author(s):  
Hiroyshi Emori ◽  
Hiroki Nakamura ◽  
Tatsuo Sumino ◽  
Tadashi Takeshima ◽  
Katsuzo Motegi ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
High Rate ◽  
Activated Sludge Process ◽  
Nitrogen And Phosphorus ◽  
Conventional Activated Sludge ◽  
Treatment Techniques ◽  
Conventional Activated Sludge Process ◽  
Denitrification Process

For the sewage treatment plants near rivers and closed water bodies in urbanized areas in Japan and European countries, there is a growing demand for introduction of advanced treatment processes for nitrogen and phosphorus from the viewpoints of water quality conservation and environmental protection. In order to remove nitrogen by the conventional biological treatment techniques, it is necessary to make a substantial expansion of the facility as compared with the conventional activated sludge process. In such urbanized districts, it is difficult to secure a site and much capital is required to expand the existing treatment plant. To solve these problems, a compact single sludge pre-denitrification process using immobilized nitrifiers was developed. Dosing the pellets, which are suitable for nitrifiers growth and physically durable, into the nitrification tank of single sludge pre-denitrification process made it possible to perform simultaneous removal of BOD and nitrogen in a retention time equal to that in the conventional activated sludge process even at the low water temperature of about 10 °C. The 3,000 m3/d full-scale conventional activated sludge plant was retrofitted and has been successfully operated.

Nitrogen Reduction – Volume Demand

1992 ◽  
Vol 25 (4-5) ◽  
pp. 233-240
Author(s):  
T. Palmgren
Keyword(s):  
Suspended Solids ◽  
Age Factors ◽  
Reduction Rate ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Aeration Tank ◽  
Nitrogen Reduction ◽  
Solids Concentration ◽  
Yearly Average ◽  
Nitrification Process

Due to the slow growth of nitrification bacteria at low temperatures, nitrogen reduction normally requires long hydraulic retention time during winter. Important for the nitrification process is the aerated sludge age. Factors influencing the sludge age are aerated volume, mixed liquor suspended solids concentration, organic loading and sludge yield. In an existing plant you cannot easily expand the volume and the load is difficult to decrease. But the suspended solids concentration can be increased by running the biological step with the contact stabilisation process. At the Käppala Association sewage treatment plant in Lidingö just outside Stockholm, one of the six aeration tanks has been reconstructed for full scale nitrogen removal experiments. In this tank the old aeration system has been replaced with rubber membrane diffusers. Further more there are several zones separated by walls in the tank. The tank can thereby be run with great flexibility. By running it with the contact stabilisation process, the sludge age has been improved by a factor between 1.5 and 2 and thereby it succeeds in keeping the nitrification bacteria in the system even during snow melting. At temperatures of about 9 °C and hydraulic retention times of less than 3 hours in the contact zone there has been a nitrification degree of up to 50 to 60 %. The experiment was conducted with a stabilisation zone of up to half the total volume of the aeration tank. The main purpose for the experiments during the winter seasons was to improve nitrification. Keeping the nitrifiers in the system had been a crucial problem during previous years. When the nitrifiers were lost with an increased flow and decreased temperature the nitrification process didn't restart until the temperature was increased and the load decreased. Usually this didn't occur until the middle of the summer meaning a loss of nitrification for up to six months. In Sweden there is a goal set for 50 % nitrogen reduction for the plants in the Stockholm region. At Käppala we manage to keep 60 to 70 % nitrogen reduction during the warm season, that is from July to December. If we can keep up the nitrification the whole year we can achieve 50 % as a yearly average under normal conditions even though we can't keep the nitrogen reduction rate as high during the cold season.

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