The worldwide harvest of aquatic products is currently close to the maximum sustainable level of the productivity. Therefore, the aquaculture is the main promoting the production of aquatic product demands. Also, the aquaculture is a way of the economical growth in developing country and rural areas by creates jobs, income and business (Pulatsu et al., 2004). However, the rapid production of the aquaculture product increases the environmental impact especially the conflict of demands, alteration of hydrologic regime, and introduction of the exotic species to the wild and pollution of the water resources (Pulatsu et al., 2004; Miller & Semmen, 2002).
The untreated aquaculture effluent discharges by pond, tank, or raceway, releases the high concentration of nutrient and solid may have seriously negative impact on the quality of water receiver (Pulatsu et al., 2004, Miller & Semmen, 2002). By the way, the increases of awareness to realizing the environmentally friendly and sustainable farming practices, the aquaculture industry are define the new ways to reduce the waste production and minimize the potential adverse impact of aquaculture. There are such as improve the raceway and tank design, treatment technologies and reuse the wastewater such as filtration and radiation method (Miller & Semmen, 2002). However, those of these methods has highly cost whereas mostly of industrial aims the low cost treatment and practically technology. Hence, the slow sand filtration is a potentially treatment with the newly media filtration use, burnt coconut shell.
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The slow sand filtration is one of the earliest technologies in water treatment whereas in beginner to prevent the spread of gastrointestinal disease. The efficacy of this treatment process demonstrated in 1892 while the cholera epidemic happens in Hamburg, Germany. However, the introduction of the rapid sand filtration in water treatment, the researchers applied this method in wastewater treatment while in recently gained popularity, especially in context of wastewater treatment for reuse (Sadiq et al., 2002). They are simple processes with percolates untreated water slowly through the porous media and then drained from the bottom. During filtration, the water passes downward through the filter bed by the combination of water pressure from above and suction from the bottom. This treatment is limited to low turbidity without any additional of chemical.
The wastewater effluent from the fish farm has a good quality of the biomass that should be apply well in various sectors. The direct usage of wastewater effluent in agriculture especially in irrigation applies without any treatment may potentially bring the health risks to the farmer and the consumers of the crops grown, impacted the various quality deteriorations over the time to irrigated soil, surface water and groundwater resources. In addition, the wastewater may contain insignificant amount of microbiological contaminant, heavy metal and organic matter (Kretschmer et al., 2003) that potentially affected the groundwater water quality in long term.
One of the most common ways used in agriculture field as irrigation, however, in recent years, the hydroponic crop become popular. Growing plants by using hydroponics system is effective way to save cost, area, and environmental products. Hence, this study will conducted of exploration the aquaculture effluent treatment by using slow sand filtration with coconut shell chars filter media effective on the application in hydroponics farming.
The aquaculture industry is one of the common activities in developing countries of promote the economical growth and income especially in rural area. However, the uncontrolled growth of aquaculture industries are compensate to the negative environmental impact due to the methods of production and environmental consequences of the production implication. The aquaculture impact varies of the conflict between needs of different users of production and water pollution problem. The water pollution problem comes from the discharges of effluent by pond, tank, or raceways to the natural.
The wastewater effluent are causes many environmental problems to the water resources especially from the fish farm. The fish farm effluent may contain many chemical compounds and pathogenic from uneaten fish food, fish faecal, treatment from illness or parasitical infection especially in tank fisheries that can be concern the natural ecosystem such as high concentration in certain chemicals content and water turbidity through the direct discharges (Tett, 2008). In previous study that has done in Turkey was shown higher concentration of total suspended solid, biological chemical demand (BOD), dissolved oxygen, NO2-N, NO3-N and total phosphorus in the stream area of fish farm (Pulatsu et al.,2004).
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The untreated wastewater also potentially poses to the high risk of health problem to human. The treatment carry out to reduces the chemical contain in fish farm wastewater and can reuse in agriculture application. Even though, the treatment applied, there are still have enough nutrient content that useful for plant crop growing, as example in Kuwait, the Tilapia culture water was utilized to grow the alfalfa crop. The effluent of the fish tanks carrying a lot nutrient that necessary uses for crop growth as the Ridha (2006) said.
In previous, the most wastewater treatment usually used slow sand filtration by using the sand and anthracite as filter media. However, the anthracite was very expensive. Therefore, the local studies choose the coconut shell char as new filter media. The usage of burnt coconut shell and sand in slow sand filtration is a new challenge in wastewater treatment especially wastewater effluent from fish farm industry.
Coconut shell is waste from coconut milk industries. The coconut milk is an important ingredient in food especially in western country such as Malaysia, Indonesia, Thailand, India, and Sri Lanka. Thus, this material is produce daily in huge amount without any alternative to reduces it. Even though, coconut shell has variety application such as locality handmade craft and others application, however that still not enough alternative to reduce the amount of production. In addition, the unused coconut shell like a mountain can bring the nuisance of eye, health risk, and environment especially the spread of dangerous disease such as Malaria and Dengue to the nearest area by the breeding of mosquitoes. Thus, the used the coconut shell as the filter media for wastewater treatment may can be reduce the amount and future increases the 'waste to wealth' application.
Hence, this study will focus the treatment of fish farm effluent efficiency by using the slow sand filtration on difference flow rates and effectiveness reuse the filtrate effluent on hydroponic method. It is expecting that the highly efficiency treatment for the total suspended solid and pathogen removal. Also, minimize the effluent discharge to the environment by reused the wastewater.
1.3 Aim and Objectives
The aim of this study is to achieve the fish farm effluent treated water can be used as the hydroponic plant fertilizer. To achieve this aim will follow the objectives below:
To determine the effectiveness of the slow sand filtration in fish farm wastewater treatment by using coconut shell chars at different flow rates.
To study the suitability of filtrate effluent is potential as natural fertilizer on green leaf lettuce (Lactuca sativa).
To analyse the presents of the pathogen and faecal coliform in crops and risk to farmers and consumers.
Scope of Study
The study follows the two main steps; slow sand filtration process and hydroponic plantation. In slow sand filtration, the filtration unit should be design and built up in a workshop. The filtration unit includes the header tank, filter column, manometer at different height, pump, valve and others apparatus. Besides, the media preparation for dual media filters sand/coconut shell in effective size and ES of 0.5mm.
The water sample will take from the tank fish farm industry (river catfish) in Selangor area. During the sampling, all the physical and chemical parameter will be consider such as pH, turbidity, and chemical content. The filtration will be operating in four different flow rates (0.1, 0.3, 0.5, and 1.0 m3/m2/hour) for sixty days to determine the optimum performance of filtration unit by their physical, chemical composition that have enough nutrient in the filtration process will be continuing to the hydroponic technique.
Then, the filtrate wastewater will used in hydroponic technique as natural fertilizer. This technique will be compare the filtrate water, raw wastewater without treatment, organic and inorganic fertilizer for the growing of Lactuca sativa or known as green leaf lettuce. This crop will be monitoring by its physical appearance and chemical composition from the seeding to harvest also the appearance of pathogen in harvest crop.
The data will be analyzing to determine the opportunities and human risk of reused untreated and treated effluent in agriculture irrigation and compared from World Health Organization (WHO) standard and previous literature review.
1.5 Limitation of Study
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The limitations of this study are:
The study will be conducting from the effluent fish farm industry by using tank or canvas technique to minimization of factor the water culture operation.
The flow rates that will be use in slow sand filtration are in range of 0.1 to 1.0 m3/m2/hour only.
The hydroponic plant will analyzed from the seeding to harvest by considering the physical appearance, chemical composition, and present of pathogen.
Significant of study
This study has the strongly significantly for the new challenges of the slow sand filtration by using the new modified media of coconut shell char without activated processes. The simple processes that can be uses in small scale and has variety choose of the others types of char's material compared the activated carbon processes. The coconut shell is a familiar material that can be defined anywhere in moderate climate such as Malaysia, Thailand, Vietnam, India and others.
The choosing of the filtration process for fish farm effluent is reasonable for the development of the aquaculture industries. The effluent usually directly discharges or recirculation back to the system. The direct discharges of the effluent may potentially disturbance to the ecosystem by present of alien microorganism and high concentration of nutrient that exceed usage. In addition, potential affect the quality of the groundwater by the infiltration process. Thus, the treated effluent may reduce the amount of biomass releases and reduction the potential effect on environment.
The aquaculture effluent has potential as natural fertilizer by the high concentration of the important nutrient for the plant growing. The direct usage of the effluent as irrigation has a risk to human. The untreated effluent contain high concentration of the chemical contain that harmful to the long-term exposure and pathogen. This is because; the untreated may contain the pathogen, faecal coliform and worm egg that can be breeding on the vegetable leave, root and stem by the irrigation and cause the food-borne disease such as food poisoning. Thus, the treated effluent before uses may reduce the potential of risk.
The aquaculture growth in economical sources give the beneficial to the developing country and the in aquaculture has led to an increase in use of feeds applied to water for improved production. The increased interest in environmental friendly farming practices, the agriculture industry focused the reduction of wastes from the aquaculture facilities (Miller & Semmens, 2002).
In previous study, the wastewater effluent directly discharges to the environment without any treatment for agriculture irrigation. The fish farm wastewater effluents especially contain the high concentration of heavy metal and pathogenic organism that may be has potentially cause health hazard (Bomo et al., 2004). Thus, the effective way solution is using the slow sand filtration.
2.2 Aquaculture waste management
According to the Miller & Semmens (2002), the waste from the fish farm is come in three general forms; metabolic, chemical and pathogenic. The metabolic waste comes in two forms from dissolved and suspended. In proper management farm, approximately 30% feed will become solid waste. The removed the solid waste decrease the downstream pollution where as reduce the dissolve organic matter. In others, the dissolve water which is appear in form of biological oxygen demand (BOD), chemical oxygen demand (COD), nitrate, ammonia, nitrite, phosphorus and organic matter (Miller & Semmens, 2002; Pulatsu et al., 2004).
In others, the reused of the fish farm wastewater potentially reduces the demanded of the water supply especially to irrigation. The untreated wastewater has a potential impact on public health and environment, which is containing high concentration of heavy metal and pathogenic element (Sadiq et al., 2002). In Table 1 below, show the exposure risk of the used untreated wastewater use in agriculture. Thus, the treatment by slow sand filtration to wastewater will increase the environment preservation.
(Sources: Health Risks of Irrigation with Untreated Urban Wastewater in the
Sourthern Punjab,Pakistan, October 2000)
2.3 Slow Sand Filtration.
The slow sand filtration as a wastewater treatment was begin since more than 150 years ago as preventing the spread of gastrointestinal disease. According to Logson et al. (2002), the efficacy of slow sand filtration demonstrated in Germany, 1892 where as two cities involved of outbreak the cholera epidemic. The cities are Hamburg and Altona. The Altona is a city used the slow sand filtration to purity their water received however, Hamburg lacking the slow sand filtration causes 8,605 of person death in Hamburg and only 32 of people's death in Altona. The death in Altona attributed as infections from Hamburg. This event shows that the slow sand filtration is efficient in controlling the microbiological contaminant and avoidance of spread of disease. As a result from the Hijnen et al. (2004) study can be strong proving that the slow sand filtration have high efficacy to eliminate peak concentration of persistence microorganisms such as (oo)cysts of Cryptoporidium and Giardia with more than(>5 log10). The slow sand filtration is also has own beneficial such as effective to remove Giardia cyst, virus and coliform bacteria (Logsdon et al., 2002; Hijnen et al., 2004) from the raw water and wastewater, innovative system and low maintenance treatment process (Mah, 2007; Logsdon et al., 2002; Heller et al., 2007).
The sand filtration has beneficial in removal suspended organic and inorganic matter besides pathogenic organism such as bacteria and parasites (Clark & Clark, 1995) as small as 60 microns from the water (Miller & Semmens, 2002). In traditional design, the slow sand filtration designed with a bed in about 1 m in depth and 1 m of supernatant water. The effective size of filter sand ranges from 0.15 to 0.35 mm and the uniform coefficient should not less than five (5) and preferable less than three (3). Slow sand filtration requires a very low application or filtration rate where as depending on gradation of the filter medium and the quality of raw water. The filtration rates are typically in range 1 to 2 percent of the rates used in rapid coagulation or filtration is controlled by the size and range size of particles used (Logsdon et al., 2002; David, 2004). The major advantage of this filtration is not requiring systematic backwashing, no chemical addition, cost effective and reliable (Mah, 2007).
For the granular media filtration processes, slow sand filtration can be best performs at the filtration rate constant however, the opening and closing the effluent valves should be carefully handling because it's may affect seriously impair of the quality of filtrate (David, 2004; Logsdon et al., 2002). As the study that done by Adin (2003) is shown that the granular media filtration will be longer the operation of the filtration design compared by using the sand only; 81 days operation by using tuff and sand and only 51 days by using sand.
However, the slow sand filtration has own limitation such as required slow flow rate, continuous flow rate to preserved bacteria removal characteristics, and significant effort required to clean the filter and the cleaning impact the performance of filter, also a large land area, large quantities of filter media and manual labour cleaning (Collins, 1998; David, 2004). The treatment becomes hard in higher turbidity level of water where as quickly clog. In others, the slow sand filters do not completely to remove all organic chemicals and dissolved inorganic substances.
Coconut shell charcoal is the granular types of filtration where mostly present as granular activated carbon (GAC) or powder activated carbon (PAC). The GAC is usually utilize for the removal of suspended and/or colloidal matter in wastewater and removal the taste and odours in water supplies. The activated carbon is functional in dual application as filtration and adsorption.
According to Pollard et al. (1992) for his review, the coconut shell known as a precursor for high quality, granular carbon with extensive micro pore volumes. The coconut shell used the absorption technique to remove the inorganic and organic micro pollutant in aqueous phases. Since it first introduction, the activated carbon becomes the water industry absorbent for reclamation of municipal and industrial wastewater to portable water quality (Pollard et al., 1992; Amuda et al., 2007).
The carbon production considered the pore structure, surface area, and chemistry of carbon. This is important parameter to improve the sorption performance and increased the pollutant removal from the wastewater (Amuda et al., 2007). The maximum performance of the carbon adsorption in has greater possible surface area in small practical volume. This is because the rate of absorption is proportional to the amount of surface area of the adsorbing media. In others, the coconut shell has potentially reduces the taste, odour, and dissolved organic chemicals in the water and air (Pollard et al., 1992; Amuda et al., 2002).
2.5 Hydroponic system
Hydroponic is one of the alternative ways by reduction usage of large area and land. It is a practice of growing plants in a medium other than soil, using mixtures of essential elements dissolved in water. The word of hydroponic derived from the Greek word, "hydro" mean water and "ponos" mean working, thus combination word is form water-working (Marbaha, 1998). The hydroponic plantation is beginning since 1937 by introduction of Professor William Frederick Gericke (called as father of hydroponic), culture of plant in water. In the beginning, Gericke only plant tomato and others plants to extraordinary his backyard in mineral nutrient solution rather than soil. The result shows the tomato plant was up to 7.5 m in length. Hence, by the rapid development of green house technology in western countries expanding the hydroponics methods in the world. The hydroponic farming is the production of crops can be obtains fast without disturbance from the weather. Moreover, this technique is more environmental friendly by reduction usage of pesticides; more pest resistant and small amount of nutrient usage (Resh, 1991; Digital Universe, 2005).
The hydroponic systems have two types: passive and active hydroponic system (Resh, 1991). In passive system, the water usage stays permanently in the reservoir. This is suitable for the short-term plantation such as lettuce, mustard, and spinach. In active hydroponic system, the fertilizer was supply through the reservoir and required the pump to push the fertilizer and nutrient to the root of plants and recirculation to the reservoir (Resh, 1991). Furthermore, the hydroponic techniques can be divided by seven techniques; Ebb and Flow Technique (EFT), Deep Flow Technique (DFT), Aerated Flow Technique (AFT), Nutrient Film Technique (NFT), Drip Irrigation Technique (DIT), Root Mist Technique (RMT) or Aeroponics and Fog Feed Technique (FFT) (Marbaha, 1998) where as different techniques for each others. However, among of these techniques, NFT is mostly using in hydroponic farming for the research and industries.
Risk of hydroponic crop
The hydroponic production is an alternatives of the organically food production. As example in Norway reported by Loncarevic et al. (2005), the aim of the Norway government is at 2010, 10% of the agriculture land should be organically. Thus, 30% of the farmland converted to organic area. The main fertilizer for the organically agriculture application is manure. The manure from the variety of the sources especially animal manure potentially contaminate to the vegetables with pathogen such as Escherichia coli O157, Salmonella species, and Listeria monocytogens where as Escherichia coli and Salmonella species present in the intestinal tract of animal, hence Listeria monocytogens present from decaying plants, soil and animal manure. However, from their study in Norway stated that the organically product is good, but the contaminant of faecal indicator and pathogenic bacteria still present.
In addition, the others cases in western Montana by the Ackers et al. (1998), proven that the outbreak of pathogen in leaf of lettuce causes the bloody diarrhea and abdominal cramps in 1995. Most of the patients were eat the raw of leaf lettuce from the nearest groceries in about 70% from the total cases. The assumption of the researcher done is the outbreak E coli in lettuce come from the growing, handling, and preparation of the produce. The risk of the outbreak of the pathogenic bacteria and faecal pathogen can be reducing by the using of the uncontaminated irrigation water.
This study will involve two parts of processes. There are experimental design and construction of slow sand filtration through their processes running and filtration analysis and reuse the filtrate water onto hydroponic system. There is a good paradigm to reuse the treatment wastewater to others application especially in agriculture application such as hydroponic plantation, that can be reduce the usage of natural water supply. Thus, the methodology used in this study is summarizing in Figure 3.1 below.
3.2 Wastewater sampling
The wastewater effluent from the cat fish tank will be taking from Selangor area nearest Shah Alam. The water quality for each sampling will be determining in-situ such as odour, pH and colour and turbidity. The total suspended solid, chemical content, organic matter and total coliform will be evaluating in the laboratory.
Filtration set built-up
Evaluating the filter performance and operation on different flow rate
Filtrate water analysis and Schumutzdecke analysis
Chemical Oxygen Demand
Total suspended solid
Total coliform and E. coli
Hydroponic planting preparation (Lactuca sativa)
Filtration unit set up
Running the filtration process
Column 1 (0.1m3/m2/h)
Figure 3.1 The flow of the study processes
3.3 Experimental design and construction
3.3.1 Filtration process
The slow sand filter is one of the economical media and simple processing. The study will be constructs in 10 cm width and 100 cm height of filtration unit. The wastewater from the catfish farm will be place in a storage tank. By using a pump, the water will lift to the constant head tank and then flow to the filter by gravity. The design of the slow sand filter is shows in Figure 3.2. The filter will be control by the manometer tube, which is 10 mm vertical interval for the 100 mm column and 3 mm diameter. The points of manometer arrangement from the inlet are 0, 10, 20, 30, 40, 50 and 60 mm to measure the head loss value. When the terminal head loss occurs, the system should be cleaning.The upper layer of the filter bed would be scrapping out. Then, after finishing, the water will refill through the underdrains.
In this study, the direct filtration is uses to treat effluent. Before the operation running, the reverse flow of the media is allow to makes sure the granules will arranges according to the size and specific gravity. Then, the media will be washes to determine the filter's capacities in term of operation. The control valves open at the effluents pipe continuously to get the constant flow needed and to maintain the flow rate when the media becomes clogging.
The water filters will be analysed in four flow rates; there are 0.1, 0.3, 0.5, and 1.0 m3/m2/hour. The operation will be operating for 60 days for the performing of filtration. The filtrate wastewater then will analyzed their quality by using UV spectrophotometer. The comparison of effluent and influent amount of chemical concentration, turbidity, and head loss will be compares. The turbidity and head loss will be measuring at the different time interval.
Figure 3.2 The design of the filtration constructs and processes.
3.3.2 Filtration media preparation
The processes will begin with the filter media preparation. In this stage, sand collected from the river will be washes to remove the finest grains and others impurity material to make sure the lower coefficient of uniformity and high average of particle diameter. In others, the sand used should not more than 20% of calcium and magnesium that considered as carbonate. The sieving process is to determine the particle size distribution curve for sand and media. Before the sieving processes, the material will be preparing into two sections. One of the sections will be consider as overall stock media and others will used in sieving. In the previous study from A. Jusoh et al. (2006), the effectiveness study of the media (coconut shell chars and sand) in range of 0.5 to 2.5 mm with the uniformity coefficient of 1.5.
The coconut shell will take from the nearest industry areas of coconut shell production in Bagan Datoh, Perak. Before burning, the coconut shell will be soaking with hot water and sodium hydroxide 5% for 24 hours to remove the oil. Then, it is will be dried in the air for 48hours. After dried, the coconut shell will be burn in the furnace at 600oC for one hour without oxygen; the furnace should be pre-heat until 400oC before feeding the raw shell. Then the coconut shell will be ground into granular and wash before sieving to determine the curve of particle size distribution. The raffle box is used to determine the size distribution same as sand determination procedure. The coconut shell will be grade into specific uniformity coefficient and effective sizes. The specific sizes and uniform coefficient of sand will be grade as shows in equation 3.1, 3.2, and 3.3.
Percentage of usable raw media: Pusable = 2(P60-P10) (3.1)
Percentage smaller media: Psmall = P10-0.2 (P60-P10) (3.2)
Percentage larger media: Plarger = P10 +1.8 (P60-P10) (3.3)
Where P60 = particles size passes in 60%
P10 = particle size passes in 10%
The media porosity is important in the filtration process. The filter bed porosity has strong influences on head loss and effectiveness of filtration in filter bed. The fill up the water in Jackson tube can determine the porosity until half of its volume. The 100 gram of the samples will be putting into the tube and shake to remove air trap. Then, the tube is filling up with the water and shakes. After the one minute, the upper level will be remark. The sample will remove and replaced by the water until the remarkable level and measure the volume of water by using measuring cylinder. Porosity media can be calculating by using the equation 3.4.
Îµ = Vv = VT-VM (3.4)
Where Îµ = porosity, dimensionless
Vv = void volume in media bed, m3
VT = total volume of media bed, m3
VM = total volume of media, m3
The specific gravity in slow sand filter is important to determine density of filter media. It used to arrange the position of media filter in dual media filter operate. To determine the specific gravity will follows by the equation 3.5.
Specific gravity = Ws (3.5)
Vs x Î³w
Where Ws = weight of granules
Vs = volume of granules
Î³w = Unit weight of water
3.3.3 Collection and analysis of samples
The water analysis considers the water quality parameters selected. In this project, the total coliform and E. coli will be analysis because there are indicator of the faecal organism in the contamination water and regular in EPA. The sample will be analysing for every 6 hour along the operation running. The others parameters like water temperature, alkalinity, chemical oxygen demand (COD), pH, turbidity, electric conductivity, suspended solid and heavy metal concentration will be analyzed for every one hour by using the specific equipment such as turbidity meter and UV spectrophotometer.
The total suspended solid will prepared in laboratory for determination of organic and inorganic matter in wastewater before and after treatment. The wastewater will be filtrate through a weighted membrane filter (Ø = 47 mm). Then, the residue will dry to a constant weight at 103 to 105ËšC temperature. This method will perform in accordance of standard methods for the Examination of water and Wastewater (APHA, 1995).
The filtration apparatus is set with insert the filter disk onto the base and clamp the funnel. The filter paper is wet with a small volume of water to seal the filter. By using the sample volume in about 200 mL, the sample is shakes vigorously before transfer to the filtration apparatus. After the filtration is finish, the filter paper is removes carefully and dries at least one hour at 103 to 105 ËšC in oven. Cool in a dessicator and weight the sample.
Table 3.1 Chemical parameters with test method
The chemical analysis of the water samples will be analysing by using HACH DR 5000 instrument kits. Table below shows the chemical parameter will be tests in from the water samples n difference flow rates.
Standard Code of HACH (2005)
HACH DR 5000
UV Screening Method
Acid Persulfate Digestion Methods
Reaction Digestion Method
From the filtration of different flow rates, the composition of the nutrient especially nitrate (N), phosphate (P), and potassium (K), will be considers to determine the suitable flow rate that have enough nutrient that can be uses in the hydroponic application.
The faecal coliform and E. coli will be detection by using Idexx Colilert. The Idexx Colilert is uses to get the quantity of bacteria that count from 100 ml sample with addition reagent. Then the quantity tray is seal before incubate for 24 hours. Then, the result will be determines from the most portable number (MPN) schedule. As precaution, the sample will store at temperature 2-25 oC away from light.
3.3.4 Schumutzdecke analysis
The schumutzdecke will be analysis at the end of the filtration running, the filter will be drain, and the schemutzdecke will be removes by using scraping the top in about Â½ in layer from the sand bed. The schumutzdecke will be suspended in the distilled water with the volume is known and thoroughly mixed. The distilled water will be adding in different volumes depend on the thicker of the schumutzdecke which is the different flow rate produce different thickness of schumutzdecke. The sample will be analyzing to determine:
ChemicalOxygen Demand (COD)
Total coliform and E. coli
3.4 Hydroponic Technique
The hydroponic system will choose the suitable area, which has a good condition such as temperature and light. The chosen of culture water system is a true hydroponic system and simplest design. Nutrient water from the tank will be flow to the root of plant by using a pump and returning back tank. In this system, the plant roots totally immerse in the nutrient solution that flow by pumping the nutrient from the tank, and then directly grow into reservoir. The aerator will be installs to the solution to avoid nutrient settling down. The schematic diagram of nutrient flow technique (NFT) is shows in Figure 3.3.
Figure 3.3 The Schematic diagram of water culture system (Dave Hydroponics Experiment accessed on http://www.dbcourt.co.uk/hydroponics, 2009).
The hydroponic will be setting up with four containers, which is contain organic fertilizer, inorganic fertilizer, raw effluent without treatment, and filtrate effluent water. The organic and inorganic fertilizer will be prepared followed the fertilizer concentration in about 560-840 part per million (ppm) with the specific ratio of nutrient for the lettuce grown.
The seed of green leaf lettuce (Lectuca sativa) will places into the hydroponic basin with the wet wool for the two or three days with tap water at the first. After seven to ten (7-10) days, the fertilizer will be adding into the water for the inorganic and organic fertilizer. For the water of filtrate and effluent, the seed is directly place to the cup to grow. The pH water solution in the entire containers will be control in around 6.0 to 7.0 to minimise exceeds of nutrient and growing disturbance
The grow period of green leaf lettuce will be analyses for every three days by their growth and height of plant. The height of crop will be analysing by using a ruler. The leave width is analysing by using the measurement tape and the changes of leaves colour. This is important to indicate the unsuitable condition due to lack of nutrients in water solution.
The hydroponic water will be change twice a week to maintain the quantity of nutrient in the reservoir. After the harvest operation, the leaves, stems, and roots of green leaf lettuce (Lectuca sativa) will be analyses for the chemical content by using the HACH DR 5000 instrument. The types of the chemical analysis from the lettuce samples is analyze same as water sample which is shows in Table 3.1.
From this study, the high expectation that the slow sand filtration by using coconut shell chars has high effectively to reduce the total suspended solid, faecal pathogen and chemical content from the catfish farm effluent from the different flow rate. In addition, it can be minimizing the health risk of the farmer by the infection and spread of the water bone disease from the aquaculture effluent by removal the pathogenic microorganism. Thus, the slow sand filtration by using coconut shell chars without activated process is an alternative of the fish farm effluent treatment in aquaculture industry. In others, the high expectation that the filtrate effluent water has still enough nutrients for the crop growing and the growing of the green leaf lettuce (Lactuca sativa) in the filtrate wastewater will be better growing compare to the others chemical nutrient fertilizer than untreated wastewater effluent. Even though, the untreated is better growing but the treated water will be to minimize the risk of the health exposure of the disease by the eaten uncooked vegetable. Thus, the treated fish farm wastewater has high potential as a fertilizer even throughout the filtration process and the important things, this method can reduce the risk of the spread of diseases by the consuming of contaminated water as irrigation for farmer and consumers especially.