5.3. Sampling and TestingIn order t

5.3. Sampling and Testing
In order to assess the system performance in terms of its applicability in the real world, the main parameters of interest focused on the pathogen reduction, nutrient conversion and pollutant removal. The main parameters of interest in this study, from a water treatment viewpoint, were the pathogenic content, dissolved and suspended solids, turbidity, dissolved oxygen, pollution potency due to oxygen demand, conductivity, pH, nitrogen and phosphorous content. For solids, material conversion and reduction in particle size and volume were of importance.
Raw blackwater samples and filtered blackwater from the VU were tested for different physical, chemical and microbiological parameters. The parameters tested at the UWS facili- ties on regular basis were TSS, TDS, turbidity, electrical conductivity, pH, DO, BOD5, COD, ammonia -N, nitrate –N and phosphate. Procedures for sampling, sample handling and testing were followed as given in the Standard Methods and Procedures for Water and Wastewater Analysis (105). Where spectroscopic instruments used, the manufacturer’s manual was fol- lowed. Microbiological analysis was done at the NATA accredited Australian Government Analytical Laboratory for E. coli and total coliform.
The same sampling and testing procedures were followed for greywater treatment as well. Samples were taken at the greywater source tank, effluent of AGT and SSF. Detailed testing of effluents of the remaining units in the system is scheduled for the next phase of the project and will be presented in the future.
5.4. Treatment Performance
The method of analyzing and describing the processes in the vermicomposting system can be complex and very time consuming. The approach adopted in this pilot scale study related to a simple input–output model, with less attention paid to the dynamics and processes within the treatment system. The advantage of this approach was that it reduced the complexity of the analyses and brought the project within an achievable timeline.
It was noted that irrespective of the weather conditions that covered all the seasons, the temperature within both VU and AGT, the temperature remained within habitable conditions for the worms. This is inferred to be the result of the channels created by burrowing worms through the solid matrix. This indicated a stable worm population in both vermicomposting units. The carbonaceous material in the matrix and the compost itself acted as insulating material in cold season, retaining the heat generated by the decomposition process.
The wooden material (mulch) added to VU to increase the bulk in assisting water drainage remained unprocessed by worms. In the AGT, an accumulation of unprocessed food organics reached an average depth of 60 mm by the end of the first week, because of high loading rate of 3.3 kg/m2/week per person. An acclimatization period was introduced with a reduced loading rate (0.88 kg/m2/week), which gave satisfactory results. In both the VU and the AGT, the worm population soon established well, and the biodegradable materials, including kitchen waste and garden organics, were converted into vermicasts by the end of the composting period of 2 months.


TSS (mg l–1) Turibdity (NTU)

120
100
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60
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1 2 3 4 5 6 7
trial #


Fig. 16.8. TSS and turbidity reductions in VU during different trial runs (Source: (84)). VU vermi- composting unit.

350
300
250
200
150
100
50
0


Period of Sampling

Fig. 16.9. TSS removal with time across the greywater treatment system (Source: (83)). GWT grey water tank, AGT aerobic grease trap, SSF slow sand filter.


An overall mean reduction of 89.32% in TSS was observed between raw blackwater and the effluent of the VU (Fig. 16.8). The TSS reductions reported from the AGT averaged at 96.2%, while SSF attained a further 98.7% reduction in TSS (Fig. 16.9). Values of the parameters in raw greywater tank (GWT) are also shown in the graphs.
The VU unit attained average 88.7% reduction in turbidity, the corresponding figures for AGT was 86.5% and for SSF 97.2%. The mean final values for TSS and turbidity, in the effluent from SSF, were 2.31 mg/L and 3.60 NTU. This was a reduction from initial mean values of 4,030 mg/L and 3,264 NTU, respectively, in the raw blackwater. The turbidity reductions were due partly to treatment in the three units as well as due to dilution in the greywater stream. Figure 16.8 shows the trend in reductions of TSS and turbidity in VU.
Most TDS readings concerning the VU increased between the raw blackwater and the treated effluent at an average 74.77% over the entire testing period. Conductivity showed similar trends to TDS, as expected. The increased TDS probably accounts for most of the change in conductivity. The mean conductivity value increased over the entire testing period


1000
800
600
400
200
0


Date of Sampling

Fig. 16.10. TDS reduction in the greywater treatment system (Source: (83)). GWT grey water tank,
AGT aerobic grease trap, SSF slow sand filter.


was 69.77%. The process of composting converts nutrients, such as nitrogen in the solid waste materials, into more soluble form (19). This could be one reason for the increased TDS. Nitrification of ammonia into nitrate also increases dissolved solids. Analysis of the influent and effluent gave an average reduction of 88.82% in ammonia levels (NH3-N) and an increase of 636% in nitrate levels (NO3-N) was noted. Phosphorous content, as reactive phosphate, also increased averaging at 182.58% over the entire testing period.
On the contrary, AGT achieved 54.8% reduction in TDS readings and SSF further reduced it by 59% (Fig. 16.10). Release of nutrients from AGT could be lower, compared to VU, due to smaller loading of putrescible organics. Also, the nitrogen content of material input to the VU is far higher than that of AGT.
The high increase in nitrate levels pointed to high nitrification rates promoted by aerobic conditions in the VU. This was confirmed by an average increase of 81% in DO readings across VU. Increase in the DO somewhat corresponded in terms of variational trends to reductions in BOD5 values (Fig. 16.11). An overall average reduction of 97.49% in BOD5 was reported between raw and final effluent across the VU, with a reduction of 70% in COD. Reductions in the organic pollutant content were consistent and gave results comparable between all the trial runs and to available data on greywater (31, 36, 73, 75, 106, 116). Increase in nitrate and phosphate levels is in agreement with studies elsewhere (116).
The greywater treatment units of AGT and SSF provided a COD reduction of 89.45% (Fig. 16.12) and BOD5 reduction of 98.1% (Fig. 16.13) The ratio between COD and BOD5 gives an indication whether or not the organic matter present in wastewater is readily biodegradable. The mean COD/BOD ratio of raw wastewater was approximately 2.85:1, which is well within the reported range (88), while that of treated effluent was 26.89:1. The ratio for AGT and SSF together was 1.7:1. This clearly means that the processes undergoing in the treatment unit conform to natural processes.
It has been observed that only 25–30% of organic matter is truly soluble, and its removal is through oxidation into CO2 and H2O. The remaining 75% of organic matter in wastewater is present in suspended form (107). It is argued that most biological treatment systems depend on gravity settling. In the vermicomposting matrix of VU and AGT, these suspended organics





120
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1 2 3 4 5 6 7
trial #


Fig. 16.11. Variations in DO, BOD5 and COD across VU (Source: (84)). VU vermicomposting unit.



600
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Date of Sampling

Fig. 16.12. COD reduction across the greywater treatment system (Source: (83)). GWT grey water tank, AGT aerobic grease trap, SSF slow sand filter.


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0
10-Jun-03 10-Jul-03 10-Aug-03 10-Sep-03
Date of Sampling

Fig. 16.13. BOD5 reduction across the greywater treatment system (Source: (83)). GWT grey water tank, AGT aerobic grease trap, SSF slow sand filter.


become entrapped within the matrix. This compost possesses significant biosorptive and bioflocculative properties, which increases compaction and enhances the removal of solids and colloidal BOD. It supports a diversity of microorganisms, the biopolymer production of which is responsible for the above properties.
As for the SSF, data from literature points out that purification of wastewater occurs within the 20–30 cm media depth (108, 109). A filter bed 35 cm deep ensured a more consistent DO concentration throughout this unit.
Microbiological analysis for faecal coliform and indicator organism E. coli showed the most important aspects of the treatment of wastewater by vermicomposting. The VU reported an average of two magnitudes of reduction in both parameters, while this improved to four magnitudes of reduction in the effluent from SSF. An average initial reading of 1.8 × 107 CFU per 100 mL in faecal coliform was reduced to an average of 30 CFU per 100 mL reading with similar readings for E. coli. Microbiological spike tests with high pathogen content also
produced consistent results. Other studies have also shown of reduction in coliform numbers by vermicomposting (117, 119, 120).
5.5. Conclusions
Tests on the working prototype system for ‘whole-of-waste’ approach in domestic waste and wastewater treatment revealed interesting and encouraging results for the wastewater stream considered. Blackwater and greywater at residential level received excellent treatment with vermicomposting technology in terms of physical and biological pollution. Further treatment with slow sand filter yielded better quality effluent. The design and construction of a low-cost aerobic greywater treatment system was intended to investigate new and innovative ways to treat and recycle wastewater at a low cost.
The purpose of this study was to provide a system that woul

Kết quả (Việt) 1:

5.3. Lấy mẫu và thử nghiệmĐể đánh giá hiệu suất hệ thống trong điều khoản của ứng dụng của nó trong thế giới thực, các thông số chính của quan tâm tập trung vào các mầm bệnh giảm, chuyển đổi dinh dưỡng và loại bỏ chất gây ô nhiễm. Các thông số chính của quan tâm trong nghiên cứu này, từ một quan điểm điều trị nước, đã giải tán nội dung gây bệnh, chất rắn hòa tan và bị đình chỉ, độ đục, oxy, ô nhiễm tiềm năng do nhu cầu ôxy, độ dẫn, pH, nitơ và phốt pho nội dung. Cho chất rắn, vật liệu chuyển đổi và giảm kích thước hạt và khối lượng đã tầm quan trọng.Blackwater nguyên mẫu và lọc blackwater từ vũ đã được thử nghiệm cho các thông số khác nhau của vật lý, hóa học và vi sinh. Các thông số thử nghiệm tại UWS facili-quan hệ thường xuyên là TSS, TDS, độ đục, độ dẫn điện, độ pH, DO, BOD5, COD, amoniac -N, nitrat-N và phốt phát. Thủ tục lấy mẫu, mẫu xử lý và thử nghiệm được tiếp nối như được đưa ra trong các phương pháp tiêu chuẩn và các thủ tục cho nước và nước thải phân tích (105). Trong trường hợp các dụng cụ quang phổ được sử dụng, các nhà sản xuất của hướng dẫn sử dụng fol - lowed. Phân tích vi sinh đã được thực hiện tại NATA công nhận phòng thí nghiệm phân tích chính phủ Úc cho E. coli và tất cả coliform.Cùng một mẫu và thủ tục kiểm tra được tiếp nối cho greywater điều trị là tốt. Mẫu được chụp tại greywater nguồn xe tăng, phun ra của AGT và SSF. Kiểm tra chi tiết của tiêu thụ nước thải của các đơn vị còn lại trong hệ thống được lập biểu cho giai đoạn tiếp theo của dự án và sẽ được trình bày trong tương lai.5.4. điều trị hiệu suấtPhương pháp phân tích và mô tả các quá trình trong hệ thống vermicomposting có thể phức tạp và rất tốn thời gian. Cách tiếp cận được thông qua vào nghiên cứu thí điểm quy mô này liên quan đến một mô hình đầu vào-đầu ra đơn giản, với ít sự chú ý trả cho các động lực và các quá trình trong hệ thống điều trị. Lợi thế của phương pháp này là nó làm giảm sự phức tạp của những phân tích và đưa dự án trong một thời gian thành công.Nó đã được ghi nhận rằng bất kể các điều kiện thời tiết được bảo hiểm tất cả các mùa, nhiệt độ trong cả vũ và AGT, nhiệt độ vẫn còn trong các điều kiện ở được cho những con giun. Đây suy ra là kết quả của các kênh tạo bởi rắn giun thông qua ma trận rắn. Điều này chỉ ra dân sâu ổn định, cả hai đơn vị vermicomposting. Carbonate trong ma trận và phân compost chính nó đã hành động như là vật liệu cách điện trong mùa lạnh, Giữ lại sức nóng được tạo ra bởi quá trình phân hủy.The wooden material (mulch) added to VU to increase the bulk in assisting water drainage remained unprocessed by worms. In the AGT, an accumulation of unprocessed food organics reached an average depth of 60 mm by the end of the first week, because of high loading rate of 3.3 kg/m2/week per person. An acclimatization period was introduced with a reduced loading rate (0.88 kg/m2/week), which gave satisfactory results. In both the VU and the AGT, the worm population soon established well, and the biodegradable materials, including kitchen waste and garden organics, were converted into vermicasts by the end of the composting period of 2 months. TSS (mg l–1) Turibdity (NTU) 120100806040200 1 2 3 4 5 6 7trial # Fig. 16.8. TSS and turbidity reductions in VU during different trial runs (Source: (84)). VU vermi- composting unit.350 300 250 200 150 100 50 0Period of SamplingFig. 16.9. TSS removal with time across the greywater treatment system (Source: (83)). GWT grey water tank, AGT aerobic grease trap, SSF slow sand filter.An overall mean reduction of 89.32% in TSS was observed between raw blackwater and the effluent of the VU (Fig. 16.8). The TSS reductions reported from the AGT averaged at 96.2%, while SSF attained a further 98.7% reduction in TSS (Fig. 16.9). Values of the parameters in raw greywater tank (GWT) are also shown in the graphs.The VU unit attained average 88.7% reduction in turbidity, the corresponding figures for AGT was 86.5% and for SSF 97.2%. The mean final values for TSS and turbidity, in the effluent from SSF, were 2.31 mg/L and 3.60 NTU. This was a reduction from initial mean values of 4,030 mg/L and 3,264 NTU, respectively, in the raw blackwater. The turbidity reductions were due partly to treatment in the three units as well as due to dilution in the greywater stream. Figure 16.8 shows the trend in reductions of TSS and turbidity in VU.Most TDS readings concerning the VU increased between the raw blackwater and the treated effluent at an average 74.77% over the entire testing period. Conductivity showed similar trends to TDS, as expected. The increased TDS probably accounts for most of the change in conductivity. The mean conductivity value increased over the entire testing period


1000
800
600
400
200
0


Date of Sampling

Fig. 16.10. TDS reduction in the greywater treatment system (Source: (83)). GWT grey water tank,
AGT aerobic grease trap, SSF slow sand filter.


was 69.77%. The process of composting converts nutrients, such as nitrogen in the solid waste materials, into more soluble form (19). This could be one reason for the increased TDS. Nitrification of ammonia into nitrate also increases dissolved solids. Analysis of the influent and effluent gave an average reduction of 88.82% in ammonia levels (NH3-N) and an increase of 636% in nitrate levels (NO3-N) was noted. Phosphorous content, as reactive phosphate, also increased averaging at 182.58% over the entire testing period.
On the contrary, AGT achieved 54.8% reduction in TDS readings and SSF further reduced it by 59% (Fig. 16.10). Release of nutrients from AGT could be lower, compared to VU, due to smaller loading of putrescible organics. Also, the nitrogen content of material input to the VU is far higher than that of AGT.
The high increase in nitrate levels pointed to high nitrification rates promoted by aerobic conditions in the VU. This was confirmed by an average increase of 81% in DO readings across VU. Increase in the DO somewhat corresponded in terms of variational trends to reductions in BOD5 values (Fig. 16.11). An overall average reduction of 97.49% in BOD5 was reported between raw and final effluent across the VU, with a reduction of 70% in COD. Reductions in the organic pollutant content were consistent and gave results comparable between all the trial runs and to available data on greywater (31, 36, 73, 75, 106, 116). Increase in nitrate and phosphate levels is in agreement with studies elsewhere (116).
The greywater treatment units of AGT and SSF provided a COD reduction of 89.45% (Fig. 16.12) and BOD5 reduction of 98.1% (Fig. 16.13) The ratio between COD and BOD5 gives an indication whether or not the organic matter present in wastewater is readily biodegradable. The mean COD/BOD ratio of raw wastewater was approximately 2.85:1, which is well within the reported range (88), while that of treated effluent was 26.89:1. The ratio for AGT and SSF together was 1.7:1. This clearly means that the processes undergoing in the treatment unit conform to natural processes.
It has been observed that only 25–30% of organic matter is truly soluble, and its removal is through oxidation into CO2 and H2O. The remaining 75% of organic matter in wastewater is present in suspended form (107). It is argued that most biological treatment systems depend on gravity settling. In the vermicomposting matrix of VU and AGT, these suspended organics





120
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1 2 3 4 5 6 7
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Fig. 16.11. Variations in DO, BOD5 and COD across VU (Source: (84)). VU vermicomposting unit.



600
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Date of Sampling

Fig. 16.12. COD reduction across the greywater treatment system (Source: (83)). GWT grey water tank, AGT aerobic grease trap, SSF slow sand filter.


400

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10-Jun-03 10-Jul-03 10-Aug-03 10-Sep-03
Date of Sampling

Fig. 16.13. BOD5 reduction across the greywater treatment system (Source: (83)). GWT grey water tank, AGT aerobic grease trap, SSF slow sand filter.


become entrapped within the matrix. This compost possesses significant biosorptive and bioflocculative properties, which increases compaction and enhances the removal of solids and colloidal BOD. It supports a diversity of microorganisms, the biopolymer production of which is responsible for the above properties.
As for the SSF, data from literature points out that purification of wastewater occurs within the 20–30 cm media depth (108, 109). A filter bed 35 cm deep ensured a more consistent DO concentration throughout this unit.
Microbiological analysis for faecal coliform and indicator organism E. coli showed the most important aspects of the treatment of wastewater by vermicomposting. The VU reported an average of two magnitudes of reduction in both parameters, while this improved to four magnitudes of reduction in the effluent from SSF. An average initial reading of 1.8 × 107 CFU per 100 mL in faecal coliform was reduced to an average of 30 CFU per 100 mL reading with similar readings for E. coli. Microbiological spike tests with high pathogen content also
produced consistent results. Other studies have also shown of reduction in coliform numbers by vermicomposting (117, 119, 120).
5.5. Conclusions
Tests on the working prototype system for ‘whole-of-waste’ approach in domestic waste and wastewater treatment revealed interesting and encouraging results for the wastewater stream considered. Blackwater and greywater at residential level received excellent treatment with vermicomposting technology in terms of physical and biological pollution. Further treatment with slow sand filter yielded better quality effluent. The design and construction of a low-cost aerobic greywater treatment system was intended to investigate new and innovative ways to treat and recycle wastewater at a low cost.
The purpose of this study was to provide a system that woul