Tamagawa University, Research Institute, Tamagawagakuen Machida-shi TOKYO JAPAN (

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1 Fertilization Design at the Rice Production using Less Odor Treated Water obtained by Reducing Odor of Sewage Treatment System with Humus Pellet Bioreactor H. OGAWA Tamagawa University, Research Institute, Tamagawagakuen Machida-shi TOKYO JAPAN ( Abstract Odor problems from sewage treatment plants have been solved by confinement and ventilation, but reducing the color and odor of treated water is economically difficult and is a subject of recycling of discharged water. Humus pellet bioreactors can be attached to existing sewage treatment plants to suppress the odor of the sewage treatment plants as a whole and to prevent sludge from deteriorating and to improve the quality of treated water. The odor and color of the treated water discharged from the sewage treatment plant was reduced. In addition, we were able to obtain performance of treated water with nitrogen 3, phosphorus 1 mg / l or less throughout the year. On the other hand, there are many cases of results that can't be used for paddy rice cultivation and vegetable production etc. by ignoring plant growth and physiology (fertilizer). For that reason, laws and guidance such as having to dilute more than 50 times in order to use processed water for agriculture are being conducted without learning. It is a case of using humus pellets in sewage treatment system and using deodorized wastewater of sewage by adjusting fertilizer when used in paddy field rice production. Keywords Odor problem, odor reduce, humus pellet, bio-reactor, recycle water, rice production ODOR PROBLEM OF SEWAGE TREATMENT PLANT After wastewater treatment, the discharged water is clear but slight coloration and special odor remain, and its slight color and smell suppresses recycling. Recycling of treated water has been used in toilets, etc. However, it is not only because of the high cost by physical method, it can't be said that it has solved the color and smell. Also, since the residual color and odor feels unlikely about sanitation, agricultural use is not diffusion. Humus Pellet Bioreactor Humus pellet bioreactor can be easily attached to a sewage treatment plant and is a method of supplying soil bacteria without isolation and has a shape and performance suitable for aerobic treatment and anaerobic treatment. Pellets are shown in Photo 1, and components are shown in Table

2 1. Installation photo is shown in Photo 2. A decrease in the intensity of odor is shown in Fig. 1. Photo 1. Humus pellet Photo 2. Installation reactor tank (Rear of right) Table 1. Composition of humus pellet for aerobic treatment Shape Cylindrical pellet d.m.15mm length mm Apparent density 1.05 g/ml True density 1.50 g/ml ph 3.0 Moisture 17 % TOC 13 % T-N 12 % SiO2 44 % Al2O3 11 % Fe2O3 7 % MgO 0.3 % CaO 0.5 % Another item Organic matter 37 % Humic acid 16 % (HCl-NaOH method) The odor intensity became 100 or less at the sludge concentration tank, dehydrator chamber, dewatering cake hopper, which is a source of malodor in sewage treatment. Most of the malodorous materials are sulfur compounds and it has been shown that it has an effect on the corrosion prevention of the equipment as it decreased. Fig.1 Decrease in odor intensity of sludge concentration reservoir sludge dewatering room sludge storage hopper

3 Treated water quality The performance of treated water in rural areas in this study was BOD 5, nitrogen 3, phosphorus 1 mg / l or less (Fig.2). On the other hand, standard municipal sewage is less than BOD 50, nitrogen 10, phosphorus 5 mg / l or less. There is a problem of contamination of harmful metal elements and some contamination in municipal wastewater, and high nitrogen and phosphorus are limited to tomatoes, cucumbers etc. which require high fertilizer requirements. It can't be used for rice and leafy vegetables with low fertilizer requirements. Fig.2 Improvement of treated water performance, BOD, SS, Total-Nitrogen, Total-Phosphorus PURPOSE OF REUSING DISCHARGED WATER AFTER SEWAGE TREATMENT When using treated wastewater from domestic wastewater of rural settlement for paddy rice production, it causes excessive growth of rice caused by high nitrogen content in treated water. In general rice is ammonia vegetable plant and it is nitrate in treated water misunderstood that it can't use nitrogen. Since the paddy field is in an anaerobic condition, the oxygen in the nitric acid has been reduced to ammonia by microorganisms. It is thought that there is no fertilizer component because we want to enlighten that the treated domestic wastewater is highly clean. However, nitrogen required for paddy field rice cultivation is at a concentration of several mg / l or less, it is overlooked that we must adjust the fertilizer given before planting seedlings and nitrogen in treated water. Due to fertilizer design considering the characteristics of fertilizer requirements of paddy rice cultivation, it was examined in the actual rice paddy that the discharged water from the sewage treatment plant with high water purification ability such as the water source area can be used for paddy rice cultivation. Introduction of paddy rice cultivation and treated water use In urban areas, sewerage improvement, housing sewage, community plant, etc. were constructed, and in the rural villages wastewater treatment and septic tank were introduced and the toilet was washed. Processing of domestic wastewater in general as well as public health improvement has been carried out, and conservation of the water environment is being carried out. Furthermore, removal of nitrogen and phosphorus (N P) in biological water treatment approached the physical advanced treatment (tertiary treatment: membrane filtration, etc.) and reached 2.5 th treated water quality. Therefore, in areas where water shortage occurs, attempts are being made to use for paddy fields and fruit trees.

4 Generally, the excess of N P makes it look good growth as the leaf color improves and grows greatly, so leaf color and growth are good at the beginning of treated water use. In the latter stage of growth, rice plants collapse, fruit trees do not become fruit, since nutrient growth does not change from nutrition growth to reproductive growth due to excess N (Photo 3. 4). Common vegetable cultivation etc. and common knowledge on physiologically necessary plant nutrition in rice cultivation and fruit trees are quite different. Therefore, common sense of fertilizer requirement of general vegetables and common sense of rice and fruit trees are different but it is not distinguished, it is thought that processed water of domestic wastewater can't be used for agriculture. Photo Rice plants lodged with nitrogen excess Fig.3 Concept of nutritional requirement and fertilization of paddy rice (short grain variety) In this study, fertilizer was designed considering the characteristics of plant nutrition physiology of paddy rice (as well as fruit trees and flower plants), and wastewater treated at the sewage treatment plant was supplied to paddy fields. As there are paddy fields around rural sewage treatment plants, it

5 means that it is possible to use the treated discharge water for paddy rice cultivation. In addition, the amount of N P in the discharged water reduced by changing the fertilizer design is not only reduction effect of fertilizer (= reduction of economic burden in agriculture), more than 60% N loaded on the environment It shows that it was reduced by absorbing it in rice. Design of fertilizer background Quality is the top priority for rice cultivation in Japan. As the harvest amount is increased, the decline in quality is a matter of course, so it is impossible to think of increased sales by using treated water. Production of delicious rice with sweetness and chewy response involves producing 20% rice of garbage. Garbage rice feeds livestock. Plant physiology of Japanese rice (Japonica) requires nitrogen nutrition especially during tillage from rice planting, but it becomes unnecessary at the time when panicles are made and floral buds can be formed. After pollination, nitrogen nutrition is necessary. Therefore, when the nitrogen content is high, the plant grows quickly and large, but it has the property of not adding rice. Also, because of typhoon and rice weight, it falls before harvesting and the roots come out from the ears, so it gets rotten. Rice production fails when using treated water for conventional fertilizer design. The image of fertilizer design is shown in Fig.3.When the nitrogen concentration T in treated water is added to the fertilizer concentration N shown in Fig.3, plants grow greatly in May and June because nutrients are doubled. If we use treated water in July, August, when the rainy season with a unique Japanese climate passes and the summer water runs short, the nitrogen fertilizer becomes excessive and the Photo. 4 Supply of treated water and water meter, upper: sewage facility, lower: flood before planting

6 taste = quality becomes worse and it can't be sold. In other words, treated water in paddy rice cultivation is not water quality that can be used when water shortage occurs. It was concluded that it could be used if aggressive use to saves water by using treated water in advance and saving the excess fertilizer used in the environment. METHOD "I" prefecture "A" town is an agricultural place in Japan where rice can be harvested in early season in the Kanto region. In order to use the discharged water of "A" town next to the paddy field, construction was carried out on the drainage line of the sewage treatment plant (with sludge reforming mechanism), and a water gauge and a control plug were installed (Photo 4). The processing plant next to the paddy field was JURUS-III type, with a bioreactor(=voef reactor) installed and using discharged water (Fig.4). Cultivation was carried out according to the standard cultivation method and fertilizer management was adjusted based on the regional control calendar and adjusted to the fertilization design. The paddy field used is the place where farmland arrangement was carried out based on 20 m 100 m (20 a). Koshihikari on the front side of photo 1 and Akitachomachi on the back side. Pest control was carried out in conjunction with the local control activities, and management from the sowing to the harvest coordination was done in the same process based on the regional work history Fig.4. Illustration of a bio reactor (=VOEF reactor) applied to JARUS-III system Results and discussion of rice paddy field rice cultivation using treated water Rice paddy rice cultivars using treated water were able to obtain standard yields. The standard harvest in this area is kg, compared to 1,000 square meters (= a). The quality of rice was the highest

7 quality, there was no quality degradation due to the use of treated water (Table 3). There was no biodiversity in cultivation using agricultural water, but various kinds of organisms occurred when treated water was used. There was a difference as shown in the upper left of the photo 5 in the growth at the entrance and the exit of the paddy field, and there was no significant difference in the harvesting amount between the exit and the entrance part. On the other hand, the concentration of each component of the effluent water from the paddy field decreased by more than 90% compared to the treated water. That is, using paddy fields has been shown to be effective in reducing the use of fertilizer and removing residual components of treated water. Removal of phosphoric acid in water treatment is the only method of recovering it as sludge, and an increase in generation amount is essential to recover phosphoric acid as sludge. On the other hand, since phosphorus in the environment exerts the effect of eutrophication as the total amount, the limitation of phosphorus discharge to lakes and oceans accompanying population increase is strengthened. Photo 5. Rice production results using treated water

8 DISCUSSION OF AVOID ENVIRONMENTAL IMPACT STUDY Table 3 shows the result of the harvest volume of the cultivation test, the result of the used water amount and the total N concentration. The amount of inflowing water in this treatment plant is about 7,500 cubic meters / month, the N of discharged water discharged after treatment is 3 mg / l, P is about 1 mg / l, and the regional conditions of the most severe discharged water. It is a processing place to meet. If N and P in wastewater from this treatment plant is converted into per month, it translates N 22.5 kg and P 7.5 kg each month. The wastewater from the field shown in Table 1 was shown to have been reduced to an N concentration of about 0.5 mg / l or less, which was reduced to about 1/6 or less. Since the cultivation period of rice is from the middle of March to the beginning of September, removal of N from discharged water by paddy rice cultivation was done during the cultivation period of about 6 months. For P, the result was less than the detection limit of 0.5 mg / l or less from the accuracy of analysis. About 1 mg / l for discharged water from the treatment site, it is considered that there was a removal rate of about 50% or more. It is estimated that 37.5 kg of N was used for rice or denitrification during the six months of cultivation period. For the entire treatment facility, five months of the one-year emissions are calculated by paddy rice cultivation. If we use discharged water of about 2,500 m 3 for 20 a, we can accept all of the discharged water by using 360 a (18 paddy fields). One side of the paddy to the river in the back of Photo 1 is sufficient enough, and in the rice cultivation area it is sufficiently large enough to use a small amount of paddy fields (about a part of the area of idle fields). In addition, it is possible to reduce N of kg when all the discharged water at this treatment plant is accepted for rice cultivation, converted to 4218 kg in terms of home farming fertilizer (all 8), 420 bags in 10 kg bag It is a corresponding amount of reduction. Conclusion This sewage treatment plant has a scale of 1250 people. When the whole amount of treated water is used in rice paddy rice production, a paddy field of 360 a (a = 1000 square meters) is necessary. The amount of nitrogen fertilizer reduced is kg, which corresponds to 4218 kg as a fertilizer with a general component quantity of 8%. By conducting sewage treatment in rural areas in pairs with agricultural production, we achieved a reduction of 337 tons of fertilizer when converted to a population of 100,000 people, and a reduction effect of nitrogen load of 26 tons to lakes and oceans. By using the discharged water from the rural settlement wastewater treatment facility in adjacent paddy fields, it was possible to obtain an effect of reducing about 60% of N. In addition, it was possible to cultivate paddy rice that did not affect the yield and quality.