Yumurta tavukçuluğunda inert koi ve kirletici yüklerin belirlenmesi

Abstract

Endüstrilerden kaynaklanan kirletici yüklerin belirlenmesi, su kirliliği kontrolü doğrultusundaki çalışmaların önemli bir bölümünü oluşturmaktadır. Atıksu karakterizasyonunda kullanılan parametreler arasında organik içeriği ifade eden KOİ, biyolojik arıtımda ayrı bir öneme sahiptir. Bunun nedeni, KOİ'nin organik substrat, biyokitle ve elektron dengesi açılarından ilişki kurulmasına olanak sağlamasıdır. Atıksulardaki organik maddelerin biyolojik faaliyetler yolu ile ayrışma hızları doğal olarak aynı olmamaktadır. KOİ testi atısulardaki organik maddelerin arıtma koşulları altındaki ayrışma hızlarının farklılığını ortaya koyamamktadır. Yani atıksulardaki inert ile ayrışabilir KOİ fraksiyonlarını ayıramayan KOİ testi, bu bakımdan BOİ testine göre yetersiz kalmaktadır. Bu nedenle KOİ'nin inert kısmını tayin edecek bir yönteme ihtiyaç duyulmuştur. Biyolojik arıtım sürecini hiç bir değişime uğramadan geçen çözünmüş inert kısım, özellikle arıtma tesisi çıkışında endüstriyel atıksularda önem taşımaktadır. Bu çalışmada yumurta tavukçuluğunda devre arası temizlik işleminden kaynaklanan atıksular karakterize edilmiş ve kirletici yükleri hesaplanmıştır. Ayrıca Germirli ve diğerleri (1992) tarafından geliştirilen inert KOİ saptama yöntemi doğrultusunda atıksu numuneleri için aerobik ve anaerobik koşullarda deneyler gerçekleştirilmiştir. Bu deneylerin sonucunda yarkahane ve yumurta kümesi devrelerinden kaynaklanan atıksular inert KOİ bazında karakterize edilmiş ve uygulanabilecek arıtma tipi açısından irdelenmiştir.

In few decades water pollution has become the major problem due to the sharp increase in population, which accerelates the industrial development and rapid urbanization simultaneously. The ever increasing demand for the world's food supply will be one of the most critical future problems. Beside this fact, potential environmental quality problems appear on the scene asssociated with animal waste at husbandary facilities, runoff and leachate from manured fields. The complex structure of industries implies the necessity of a classification so that industries shall be evaluated by a systematic approach. In a pollution based classification, industrial pollution characteristics are defined according to their production patterns and groups reflecting the similiar pollutional properties are created. Furthermore, categories can be divided into subcategories and subcategories into subgroups as well, considering the differences in their production facilities. Variety of other factors that interfere with industries should be taken into account as the detailed classification is being built. In the formation stage of subcategories more attention is paid to pollution characteristics than production patterns. This stage is known as the most critical point in the categorization of industries. In Turkey, the classification of industries on the basis of pollution characteristics had been performed by ITU. In this classification all industries are divided into 59 categories and categories into subcategories, subgroups if necessary. Animal husbandary which is one of the main categories in the classification IX performed by ITU is divided into several subcategories. There exists three subgroups related to the chickens. These are given below:. Chickens, layers.. Chickens, broilers.. Chickens, layer, breed and replacement. In this study wastewater generating from the layers subgroup had been focused and experimental procedures had been carried out in this context. In layers subgroup chickens are kept in multifloor batteries for their eggs. The drinking water for chickens distributed by plastic pipes on which nozzles are fixed nearly 30 cm apart from each other. The chicken touches the bottom end of the nozzle with its beak as it drinks water. This automatic water distribution system prevents the the contact of water with wastes, so wastes remain in solid state. Food is transported through pipes by helezonic feeders between the batteries automatically. This system prevents the contamination of spilled food. Under the batteries there exists boards on which wastes are collected and scraped automatically. Waste droppings are conveyed through a collector channel under each battery. A main collector channel for wastes intersects at the ends of the collector channels under the batteries and wastes in solid state are scraped daily out of the laying houses. Some plants spread this wastes on agrigultural land while some plants store the wastes in huge concrete channels and process them to compost. There are two operational steps in the layers subcategory; the first one is to purchase a day old chicks and feed them in separate confinements for a period of 100-112 days (chicks step). By the end of this period chickens become mature enough to lay their eggs and they are transferred to another confinement called laying houses. In the second step layers are fed in the laying houses for nearly 76 weeks (532) days (layers step). Another management strategy in this subgroup is to purchase 100-112 days old chickens directly and feed them for their eggs untill the end of the period lasting 532 days. As this cycle goes on, by the end of the periods, two seperate cleaning operations are performed for hygienic reasons. First of all dry cleaning is performed manually by scraping the wastes throughout the cages and wastes in solid state are removed from laying houses. After that pressurized water of 70-80 °C temperature is used to clean the remaining wastes. The cleaning operations generate two types of wastewater of unsimiliar quantitative and qualitative characteristics related with two operational steps mentined above. In broilers subgroup a day old chicks are bred for a period of 44-56 days after which they are sold for their meat. There exists no cages in broiler houses where chickens are kept on wood shavings named as "litter" spread on concrete floor. Wastes are collected on litter and litter- waste mixture in dry form is removed from broiler houses at the end of breeding cycles. At the same time concrete floor is washed with pressurized water and wastewater generates. In modern broiler houses automatic water and food distribution systems are used both for hygienic and environmental conditions preventing the dilution of wastes and contamination by spilled food. The equipments of these systems are dismantled and cleaned by rubbing with a sponge outside the broiler house. In layer, breed and replacement subgroup a day old chicks are produced for layers and broilers subgroups. The first step is to breed a day old chicks untill they get mature enough to lay their eggs. In the second step chicks which will be layers or broilers in the future are produced. Two different types of wastewater of unsimiliar quantity and quality generate in cleaning operations performed at the end of the steps mentioned above. Two different plants for layers sub-group were examined within this study. Waste water sample collected in plant A represents only chicks step and sample in plant B represents both chicks and layers steps. In wastewater sampling procedure, composite samples of 2 I each were collected at every interval of an hour. The daily fractions of water used for flushing were estimated to obtain the total amount. Depending on the ratio of daily amount to total amount, daily composit samples were collected at the end of flushing operation. Characterization of wastewater generating from plant A and B can be given as: Table 1 : Experimental Characterization Values XI Table 1 : (cont.) Furthermore by the help of the insitu collected data in two separate steps (chicks and layers steps) performed in plant B, pollution loads of wastewater had been estimated for layers sub-group. 0,454 m3/day represents wastewater flow value for layers subgroup. Evaluation of this data with wastewater characterization resulted the following process profile for the layers subgroup in plant B: Table 2: Process Profile for Plant B XII Table 3 : Pollution Profile for Plant B Apart from this, chicks step in plant A had been examined in the same way. 0,769 m3/day represents wastewater flow value for chicks step. Evaluation of this data with wastewater characterization resulted the following unit pollution loads for the chicks step in plant A: COD of 26 g/ 1000 chickens.day, BOİ5 of 15 g/1000 chickens.day, suspended solids of 8 g/1000 chickens.day, TKN of 1,5 g/1000 chickens.day, total phosphorous of 0,5 g/1000 chickens.day and oil- grease of 1 g/1000 chickens.day. The comparison of the experimental results with the characterization data in literature proved that the literature data reflects the characteristics of raw waste XIII diluted with little amount of water, which is completely unsimiliar with the wastewater examined, on quality basis. According to traditional approach in biological treatment systems, the effluent COD is composed of the remaining fraction of the influent COD. Thus, the effluent COD level could be decreased to zero by increasing the sludge age parameter. On the contrary, recent studies proved that increasing the sludge age leads higher effluent COD levels in spite of higher COD removal efficiencies. In order to investigate this contradiction COD of wastewaters is classified into several fractions by a new approach. In biodegradability aspect there are two fractions; biodegradable and nonbiodegradable fraction. Furthermore, biodegradable and nonbiodegradable fractions are also divided into two portions named as soluble and particulate. The fractions are given below: Initially inert particulate COD, X,; initially inert soluble COD, S,; particulate residual metabolic products, Xp; soluble residual metabolic products, Sp; readily biodegradable COD, Ss; slowly biodegradable COD, X,. S, and X, components bypass through the system and affect the performance of the treatment system directly in an adverse way. For that reason, it is surely very critical to assess them in characterization stage. In the second experimental part of this study performed to assess the inert fractions in wastewater generating from both the chics and the layers steps in plant B, firstly two aeobic batch reactors of 1 I volumetric capacity were used. The first reactor was fed with raw wastewater which had been diluted in order to get an initial total COD lower than 1 500 mg/l and the second one with filtered wastewater in the same dilution ratio (in the ratio of soluble COD to the total COD in raw wastewater). The method proposed by Orhon, et. all had been used in this experiment. The biomass content in reactors were 40 mg/l VSS and the filtrate from GF/C glass fibre filter paper was considered to represent the soluble fraction of wastewater. In the tests with wastewater from layers step, two more reactors in which a nitrification inhibitor had been added were used because of inapproriate C:N:P ratio. The experiments resulted as: 349 mg/l inert COD for the chicks step, 98 mg/l inert COD for layers step in the effluent of an aerobic biological treatment system. The unit pollution loads in the same conditions were founded as: 0,4 g/1000 chickens.day for chicks step xiv and 14,7 g/1000 chickens.day for layers step. Same tests as done in aerobic conditions were also performed in anaerobic conditions to assess inert COD fractions in both samples collected in plant B. In both experiments initial total COD levels were below 1 500 mg/l and anaerobic biomass of high activity had been used to maintain 40 mg/l VSS concentration in each reactor at 35 °C. Sodium bicarbonate was added to reactors for alkalinity supply of 1 500 mg/l CaC03. The experiments resulted as: 980 mg/l inert COD for chicks step, 1 570 mg/l inert COD for layers step in the effluent of an anaerobic biological treatment system. The unit pollution loads in the same conditions were founded as: 0,7 g/1000 chickens.day for chicks step and 23,6 g/1000 chickens.day for layers step. As a conclusion, aerobic treatment system for carbon removal was decided to be sufficient for the wastewater generating from the layers subgroup and it is not possible to get lower unit pollution loads lower than the values which are given above for aerobic system. Beside this point, it is concluded that the layers step is more important on the basis of water pollution than chicks step and the efficiency of dry cleaning before washing at the end of breeding periods determines the strength of watewater.