Báo cáo khoa học nông nghiệp " Treating and recycling waste and soils from fish ponds in the Mekong Delta to improve livelihood and reduce water pollution" pdf

&: !=n. I.$. .!wB;?, , + : Australian Government .:.A>. :; ; .', ;; * 72;-*st"A;A ;-:-::c: 9: .z4.: Ministry of Agriculture & Rural Development ,:' AUS AID Project Progress Report 023/06VIE Treating and recycling waste water and solids from fish ponds in the Mekong Delta to improve livelihood and reduce water pollution + < .:t MS2: FIRST SIX-MONTHLY REPORT 7"' January, 2008 Table of Contents 1. Institute In formation 1 2. Project Abstract 2 3. Executive Summary 2 4. Introduction & Background 3 5. Progress to Date 5 5.1 Implementation Highlights 5 5.2 Smallholder Benefits 9 5.3 Capacity Building 9 5.4 Publicity 9 5.5 Project Management 9 6. Report on Cross-Cutting Issues 9 6.1 Environment 9 6.2 Gender and Social Issues 9 7. Implementation & Sustainability Issues 10 7.1 Issues and Constraints 10 7.2 Options 10 7.3 Sustainability 10 8. Next Critical Steps 10 9. Conclusion 11 10. Statuatory Declaration 11 1. Institute Information Contact Officer(s) Project Name Vietnamese Institution Vietnamese Project Team Leader In Australia: Team Leader 023106VIE Cuu Long Rice Research Institute Dr. Cao van Phung Name: Richard Bell Position: Professor Organisation Murdoch University Australian Personnel Dr. Richard Bell Date commenced April 2007 Completion date (original) February 20 10 Completion date (revised) March 20 10 Reporting period April- October 2007 In Australia: Administrative contact Name: Richard McCulloch Position: General Manager Organisation Murdoch Link In Vietnam Name: Cao Van Phung Position: Head, Soil Science Dept. Organisation Cuu Long Rice Research Institute Telephone: +61 8 93602370 Fax: +6 1 8 93 104997 Email: R.Bell@murdoch.edu.au Telephone: +61 8 93607566 Fax: Email: R.Mcculloch@murdoch.edu.au Telephone: +84 71 861452 Fax: +8471861457 Email: phungcv@,vahoo.com.vn caovanphung@hcm.vnn.vn 2. Project Abstract - The use of fishpond waste at Chau Phu and Phu Tan districts of An Giang province showed that fishpond waste by farmers increased rice yield significantly about 1 tonneha because solid waste from fishpond has higher content of available nitrogen, phosphorus, potassium, calcium, magnesium as well as micronutrients. - A field experiment was conducted using three doses of solid wastes (1, 2 and 3 tonneha) in combination with 113 and 213 of the recommended inorganic fertilisers rate (60N-40P205-30K20). Rice yields are more or less the same in all treatment, suggesting that the fishpond waste relaced 113 to 213 of the fertiliser normally applied. The results again confirmed that solid waste from fishpond can be recycled for rice culture to mitigate pollution of waterway. - Denitrification bacteria (Pseudomonas stutzeri) caused ammonia, nitrite and nitrate concentrations in waste-water from fishpond t decrease strongly from 9 mg5 to below 1 mg5 (NlaN7a) and 0 mg/L (N2aD3b) after 2 days, meanwhile ammonia concentration of control treatment only decreased from 9 to 7 mg/L. 3. Executive Summary - Questionnaires for baseline study were formulated in consultation with researchers of Can Tho University, and with extension officers in Can Tho city and An Giang provinces. In total 240 questionnaires of stakeholders were collected (2 districtslsite). The preliminary results showed that all stakeholders were concerned about surface water pollution because of its effects on their business sustainability and livelihood. There were about 20 % of the farmers (including both fish and rice farmers) stating that water quality is bad. There are only 5% of fishpond holders having settling ponds, 12 % of them practice waste recycling on paddies and the rest discharge directly to the waterway. Farmers practicing fish culture are richer, high educated and younger than those carrying out rice cultivation. However, about 15 % of fishpond holders are recent migrants who have bought or rented lands from local farmers. Impacts reported on water quality include greenish-black colour, bad smell, high turbidity, causing itching on contact. Moreover, farmers raising fish recognised that percentages of diseases infected. fish is much higher (about 15%) than before (< 5 %). The demand for effective and economical solutions for control of water pollution is the first priority of stakeholders. - The survey of farmers' practices on fishpond waste treatment was completed during the dry season 2007 at 2 sites (An Giang province and Can Tho city). Most of the wastes (liquid and solid) are pumped directly into waterways (rivers or canals). In the case of fishponds located nearby big rivers (Tien and Hau), waste is apparently diluted by the large volume of water flow and it is not reported to cause much problem in comparison with discharge situated at the far end of small rivers or canals. Under some circumstances, waste was discharge into paddy fields. A concern requiring management arises mainly due to high content of nitrogen in waste causing yield loss by lodging. However, a judicious use of waste in balance with inorganic fertiliser application may increase rice yield in some cases. - During the dry season 2007, we conducted a study on "Effect of waste application on rice yield in An Giang province". We selected 32 paddies wherein 16 fields received waste through discharges from fishponds while the others did not. Results showed that rice yields in fields receiving waste were 0.8-1.0 tonneslha higher than those that did not receive waste. This might be due to high nutrient content in waste especially available nitrogen, phosphorus, potassium as well as secondary and micronutrients. - A field study on the beneficial use of solid fishpond waste for rice cultivation was carried out during the wet season 2007 at the experimental farm of Cuu Long Rice Research Institute. Three dosages of waste at the rate of 1, 2 and 3 tonnesha were applied in combination with 113 and 213 dosages of inorganic fertilisers. The 100 % rate of inorganic fertilisers (60N-40PzOs-30K20) served as the control. There were no significant differences in rice yields over all treatments. This indicated that uses of solid waste from fishpond can save money for farmers by reducing fertiliser inputs. - The analysis of water collected from fish ponds indicated that it is high in water soluble nitrogen, total suspended solids while coliform bacteria was at the limits under regulation No.212006 of the Ministry of Fishery\ies. - Eight isolates and one strain of denitrifying bacteria Pseudomonas stuzeri were collected from fishponds in the Cuu Long Delta for microbial treatment of waste water. Results showed that ammonium contents in waste water treated with denitrifying bacteria decreased quickly from 10 mgL at day 0 to 0 mgL at day 4. Meanwhile in BKC and control treatments, ammonia remained at 2 mg/L after 4 days. Nitrite concentration in control treatment increased up to 3 mgL at day 2. Other treatments maintained nitrite level below 0.5 mgL. Nitrate was detected only in control tank at day 4. It might be concluded that BKC and denitrifying bacteria has the ability to reduce nitrite and nitrate in waste water, however, further experiments will be undertaken to determine the fate of the ammonium lost from solution. 4. Introduction 8 Background Fishpond aquaculture is as a major industry in the Mekong Delta. However, wastewater and solid waste discharge from fish ponds is causing pollution of canals and rivers harming the quality of water used for household purposes and threatening the future of the aquaculture industry itself. There is a clear and urgent need to develop strategies for reducing waste discharge from fish ponds so that the fishpond aquaculture industry can continue to support income diversification in the Mekong Delta, while complying with the water quality discharge standards outlined in Vietnamese law and regulations (Ministry of Fisheries 2006)'. Water in fish ponds is replaced frequently generating large quantities for disposal or re-use. Currently wastewater is mostly discharged into communal rivers and canals, but this has caused significant downstream water pollution, such that most of the aquaculture is now located in the headwaters of catchments. In order to reduce pollution, National Environmental Law introduced in 2005 prohibits direct wastewater discharge into rivers and canals. Offenders may either be fined or their operation closed until compliance is achieved. In addition annual emptying and cleaning of solid waste from the base of fish ponds is essential to control the spread of diseases among fish. This produces an organic-rich sluny comprising about 35 % solids. Discharging this slurry into communal waterways is also - 1 Ministry of Fisheries (2006). Maximum concentration limits allowable for pollutants discharged to waterways. Regulation No. 02/2006. Issued March 2006. prohibited under the law. However, there appears to be poor compliance with the law in discharge from fish ponds. Strict compliance with the law without cost-effective treatment and recycling strategies would have a crippling effect on the fishpond aquaculture industry. It is critically important to develop effective strategies for fishpond operators so that they can treat wastewater and solid wastes to meet discharge standards without large costs. While there is widespread acceptance that water pollution from fishpond discharge is prevalent, there appears to be little evidence gathered and published on the problem. In particular there appears to be a lack of baseline water quality data from which to demonstrate a decline in water quality. Moreover, there is little current monitoring of water quality in the medium to small sized canals in which the water pollution problem is most obvious. Hence it remains unclear what water parameters fail to meet the Vietnamese water quality standards, how frequently breaches occur, where they occur and the key risk factors. From first principles, it is likely that the water pollution problems are most severe during the dry season when flushing and mixing of discharge water is least, and in the smaller canals especially where their flow is blocked by aquatic plants and by barriers. The Mekong Delta produces 400,000 t of catfish per annum mostly in freshwater ponds. Most of the fish are exported to the USA, and increasingly to European countries and Japan. The exported fish must meet sanitary requirements in these markets. A major variable in producers' capacity to control the inputs to fish ponds is the water used to fill ponds, which is drawn from rivers and canals. However, under the cumulative influence of intensive fishpond aquaculture, a decline in quality of river and canal water from the discharges is limiting productivity and expansion of fishpond aquaculture by causing the downstream spread of bacterial disease and parasites in the water. It may also be impacting adversely on the health of families that draw significant amounts of their domestic water from these polluted sources. The challenge of this project is to protect the fishpond aquaculture industry which is a source of diversified income for farmers in the Mekong delta by treating the waste water and solids from fish ponds, whilst at the same time protecting the environment and householder users from water pollution. The expected outputs are directed to improving competitiveness of fishpond aquaculture producers in the Mekong Delta. In addition, technologies to be developed will improve natural resources management by decreasing water pollution from uncontrolled discharge of fishpond waste water and solids into rivers and canals. The overall Project objective is to improve the sustainability of fishpond aquaculture production and water quality in the Mekong Delta. Specific Project objectives are: e Develop effective treatment strategies for wastewater and solids from fishponds before discharge to reduce water pollution; e Develop resource recovery and re-use strategies for waste water and solids from fish ponds including land application and novel end uses; 0 Increase stability of household income from fishpond aquaculture through encouraging diversification of production and markets in the Mekong Delta. This project targets fishpond aquaculture, not other types of aquaculture such as cage aquaculture and shrimp aquaculture. Cage aquaculture is declining in importance due to rising costs and riskiness of the production system compared to pond culture. Other studies have examined shrimp aquaculture in brackish water environments (Be, 1997). Shrimp aquaculture is also under threat due to environmental impacts. Hence, there are lessons to be learnt from other forms of aquaculture, in particular the need to address environmental issues that can impact on the sustainability of the industry even when economics for it are favourable. Fishpond aquaculture is practiced by three main groups in the Mekong Delta: farmers using the VAC system to recycle waste water and solid wastes from fish ponds; small farmers who have both fish ponds and crop land but without integration of these components of the farm; specialist producers who essentially use all of their land for fish ponds. The VAC system already practices re-cycling of wastewater and solid waste to recover nutrient resources. In so doing the level of pollution caused by water discharge is probably decreased. However, there appears to be little evidence to demonstrate the benefits of the VAC system for downstream water quality. The present project will assess the impact of the VAC system on water quality in downstream canals, and as necessary examine modifications to the recycling of wastewater and solid waste in order to meet water quality standards for discharge. The second group of producers comprises small farmers who have a few fish ponds within a farm carrying out crop production for padi andlor fruit trees and vegetables. The present Project is particularly relevant to these two groups of producers who have sufficient land for wastewater and solid waste treatment by re-cycling, but are currently discharging wastewater and solid wastes directly into canals. Both liquid and solid waste from aquaculture contain carbon and nutrients which can be recycled on farms to boost production of rice, vegetables and fruit trees, as well as novel products for small scale agro-industry. Solid wastes can be treated in a number of ways, including land application, vermi-composting, microbially-activated decomposition and ozone treatment. However, research is needed to ascertain the potential of each method for treating wastes and improving water quality, and to gather evidence of their effectiveness in meeting water quality outcomes. The specialist fishpond producers generally have inadequate land remaining for recycling wastewater and solid waste. Currently wastes are discharged directly into canals and rivers, sometimes after treatment with biocides. Further investigation is needed to determine the impacts of biocides on the downstream environment. In addition, opportunities need to be explored for cooperative arrangements that allow the disposal of wastewater and solid wastes from the specialist producers onto neighbouring farmers' land. However, the best practices for carrying this out still need to be developed, and once established can be extended to this group of producers. 5. Progress to Date 5.1 Implementation Highlights Baseline study: Questionnaires for baseline study were formulated in consultation with researchers of Can Tho University, and with extension officers in Can Tho city and An Giang provinces. The survey was conducted in September and October, 2007. In total 240 questionnaires of stakeholders were collected (2 districts/province). Data is now being analysed by the Department of Socio-Economics of Cuu Long Rice Research Institute. Preliminary results showed that all stakeholders were concerned about surface water pollution because of its impacts on sustainability of production and livelihoods. There were about 20 % of the farmers (including both fish and rice farmers) stating that water quality is bad. There are only 5 % of fishpond holders having settling ponds, 12 % of fishpond farmers practice waste recycling on paddies and the rest discharge directly to the waterway. Farmers practicing fish culture are richer, better educated and younger than those carrying out rice cultivation, based on numbers of concrete houses, living commodities, pumping machines and incomes. However, about 15 % of fishpond holders are recent migrants who have bought or rented lands from local farmers. Impacts reported on water quality include greenish-black colour, bad smell, high turbidity, and skin itching on contact. Moreover, farmers raising fish recognised that percentages of diseases infected fish is much higher (about 15%) than before (< 5 %). The demand for effective and economical solutions for control of water pollution is the first priority of stakeholders. The investment for raising fish is large and most of farmers is lending either from bank or their neighbours hence they are concerned about threats to the viability of the operation. Survey of farmers' practices on fishpond waste treatment: The survey of farmers' practices on fishpond waste treatment was completed during the dry season 2007 at 2 sites (An Giang province and Can Tho city). Most of the wastes (liquid and solid) are pumped directly into waterways (rivers or canals). In the case of fishponds located nearby large rivers (Tien and Hau), waste is apparently diluted by the large volume of water flow and it is not reported to cause much problem in comparison with discharge situated at the far end of small rivers or canals. Under some circumstances, waste was discharge into paddy fields. A concern requiring management arises mainly due to high content of nitrogen in waste causing rice yield loss by lodging. However, a judicious use of waste in balance with inorganic fertiliser application may increase rice yield in some cases. During the dry season 2007, we conducted a study on "Effect of waste application on rice yield in An Giang provinceyy. We selected 32 paddies wherein 16 fields received waste through discharges from fishponds while the others did not. Results showed that rice yields in fields receiving waste were 0.8-1.0 tonneslha higher than those that did not receive waste (Table 1). This might be due to high nutrient content in waste especially available nitrogen, phosphorus, potassium as well as secondary and micronutrients (Table 2). However, organic carbon content in paddies receiving waste were lower. This problem is under studying to clarify whether farmer used only liquid waste for irrigation. Table 1. Average rice yields (tha) in paired sites in An Giang province with and without fishpond sediment application. Values are means of 8 replicates. Water qualitv sampling: Three study areas have been selected: Chau Phu and Phu Tan in An Giang Province; Thot Not in Cantho district. In addition, water sampling is proposed for Binh Thuy and Phong Dien districts near Cantho city, in areas practising VAC. Without fishpond sediment 6.9 6.6 District Chau phu Phu Than Table 2. Pond sediment composition from survey in An Giang province, 2007 Plus fishpond sediment 7.9 7.4 Element C N P K Concentration 2.5 % 0.83 % 0.61 % 3.5 % The sampling proposed for 8 ponds was as follows: Pond water (surface), Pond water (2 m depth), Drain water at gate Downstream 100-200 m Plan is for sampling 2 times per month for 5 months. Waste recycling practiced Some farmers use liquid waste from fish ponds for rice cultures Controversies on liquid waste application on rice Settling pond, tree lot irrigation, rice padi application Landfill on orchard, watering vegetable and rice Landfill on orchard, watering vegetable and rice Water quality measurements proposed: Chemical properties: pH, EC, BOD, COD, Nos, P, S, Biological properties: E coli, Total coliform, Staphyllococcus, Salmonella. Feeding Own feed mixing plus pellets Own feed mixing plus pellets Pellets and own feed mixing Pellets feeding at fingerling about 1 month then own feed mixing Pellets feeding at fingerling about 1 month then own feed mixing However, a number of factors should be considered in sampling: 1. Control sites- Most catchments will have background inputs of pollutants to canal water from rice farming, and human settlements. The background impact of these on water quality needs to be determined by water sampling at control sites beyond the influence of fishponds. The location of the control sites will vary from site to site. 2. Low tide sampling- During low tide water drains out of the catchment and at this time discharge of wastewater is most likely. Sampling should coincide with such periods of discharge to capture the peak in pollution events. 3. High tide sampling- During high tide back flow of water from rivers and main canals to small canals occurs. Refilling of fish ponds is likely during these times. Sampling should also be planned to coincide with such periods of discharge to capture the base load in pollution events. Closest drainage Small drain discharging through gates to large canal Discharging through gates to small canal Mainly to canals, some was discharged on padi Small canal Small canal District Chau Phu Phu Tan ThotNot Binh Thuy Phong Dien Aquaculture system Large fishponds, recent development Large fishponds, recent development Large fishponds, operating 8 years Small fishponds Small fishponds 4. Sampling protocols- Cantho University has a set of sampling protocols. Protocols should describe sampling locations (depth, distance from bank), cleaning of sampling bottles, storage conditions for samples after collection. 5. GPS positioning of sampling sites- To ensure sampling is repeated at the same positions GPS coordinates should be taken for sites. 6. Water quality- after the MSc student finishes sampling in December, further dry season sampling is needed to provide a complete view of the annual cycle of pollution from fishpond waste water. 7. After results are available for the first 4 sampling periods, a summary of the data should be circulated to Murdoch so that the project can discern trends and determine whether variation in sampling plans can be made. 8. The variables expected to contribute to pollution levels from fishpond waste water are: size of the canal into which discharge occurs; tide level; time of the year; distance from discharge; frequency of wastewater changes in pond; density of fishponds discharging fi-om drain; whether solid waste or only waste water is discharged; the extent of wastewater treatment in settling ponds or padi fields. It was agreed in principle that the focus of the project was not on dispersion of waste water in canals, which could be complex and require extensive sampling points, repeated often over time, but rather the levels in drains discharging into the main canals. Field experiment on the use of solid fishpond waste for rice: A field study on the beneficial use of solid fishpond waste for rice cultivation was carried out during the wet season 2007 at the experimental farm of Cuu Long Rice Research Institute. Three dosages of waste at the rate of 1, 2 and 3 tonnesha were applied in combination with 113 and 213 dosages of inorganic fertilisers. The 100 % rate' of inorganic fertilisers (60N-40PzOs-30Kz0) served as the control. There were no significant differences in rice yields over all treatments. This indicated that uses of solid waste from fishpond can save money for fanners by reducing fertiliser inputs. This experiment will be repeated during the dry season 2007-2008 at the same site. Recvclinn of waste water for rice irrigation: One experiment on recycling of waste water for rice irrigation has been carried out from August 2007. It will be harvested by the end of November. Water quality in fish ponds: The analysis of water collected from fish ponds indicated that it is high in water soluble nitrogen, total suspended solids while coliform bacteria was at the limits and the smell was bad in reference with the Standard for regulation No.212006 of the Ministry of Fisheries. Microbial treatment of wastewater: Eight isolates .and one strain of denitrifying bacteria Pseudomonas stuzeri (reference strain ATCC14405) were collected from fishponds in the Cuu Long Delta for microbial treatment of waste water. Four isolates were selected based on the ability to reduce ammonium, nitrite and nitrate in liquid waste collected from fishponds. Another treatment was BKC (benzalkonium chloride), a commonly chemical used by farmers, and a control (untreated). Results showed that ammonium contents in waste water treated with denitrifying bacteria decreased quickly from 10 mglL at day 0 to 0 mg/L at day [...]... are using re-cycling or treatment technologies for waste, yet there appear to be yield benefits for rice producers from judicious use of fishpond waste 10 Statuatory Declaration STATUTORY DECLARATION COLLABORGTION FOR AGRICULTURE AND RURGL DEVELOPMENT PROGRGM CARD Project Title: - Treating and recycling waste water and solids from fish ponds in the Mekong Delta to improve livelihood and reduce water. .. Field visits to fishponds practising waste treatment of fish pond waste at OMon and Thot Not district Calculating optimum fertiliser rates when using waste water and solid waste 9 Conclusion The preliminary investigations support the basis for the project by indicating that water pollution is perceived to be a widespread problem in the fishpond industry itself Moreover, initial field investigations... Activities And Inputs Project Title: Treating and recycling waste water and solids from fish ponds in the Mekong Delta to improve livelihood and reduce water pollution Vietnamese Implementing Institution: Cuu Long Rice Research Institute Narrative OBJECTIVES OUTPUTS PROPOSAL Performance Assumptions Measures 1 Develop effective treatment strategies for That is possible in 3 Compliance of discharge of wastewater... discharge of wastewater and solids from years to develop and wastewater and fishponds into the aquatic environment to demonstrate the solid wastes with reduce water pollution effectiveness of one or Ministry of more treatments for Fisheries wastewater and solid Maximum wastes concentration limits allowable for pollutants discharged to waterways Regulation No 0212006 1.1 Impacts of water pollution on 1.1... disseminated to farmers Smallholders cultivate rice can save a lot of money for inorganic fertilisers 5.3 Capacity Building One BSc student of An Giang University completed his thesis entitled " Effect of waste discharge to paddy on rice yield" Two MSc students from Can Tho University are now carrying their thesis on Treating and recycling of solid and liquid waste from fishpond 5.4 Publicity None to. .. tracking the fate of all forms of N in the solutions Signed for the Australian Institution by a duly authorised officer in the presence of witness Signature of Witness Insert Name and Title Insert Name and Title 3; EQUIPMENT AND SERVICES HANDOVER This is to certify that the above personnel inputs have been delivered and the equipment and services identified above provided has been handed over to the. .. soils Types of waste applied to soils, particularly organic waste and waste water Rice nutrient requirements Principles and methods of waste application Environmental impacts of waste application on land Case studies in land application of wastes Possible lab and workshop sessions: Soil organic matter determination Characterisation of waste water and water quality Field experiment on solid waste application... will visit in later December 2007 to jointly conduct a training workshop on land application of organic waste with Dr Phung During this visit a detailed project review will take place and selection of candidates for training visits to Australia in 2008 will be completed CLRRI will host the training courses at CLRRI The Institute is able to accommodate up to 30 participants, cater on site, and has adequate... waste from fishpond was collected for composting and vermiculture testing in the green house of the Cuu Long Rice Research Institute (CLRRI) These two experiments are still going on 5.2 Smallholder Benefits Water discharges from fishpond can be used for rice cultivation to make use of high soluble macronutrients content in waste water The technique on rice cultivation irrigated with fishpond waste. .. Meanwhile in BKC and control treatments, ammonia remained at 2 m g 5 after 4 days Nitrite concentration in control treatment increased up to 3 mg/L at day 2 Other treatments maintained nitrite level below 0.5 mg/L Nitrate was detected only in control tank at day 4 It might be concluded that BKC and denitrifjing bacteria has the ability to reduce nitrite and nitrate in waste water Vermi-composting: Solid waste . Objectives, Outputs, Activities And Inputs Project Title: Treating and recycling waste water and solids from fish ponds in the Mekong Delta to improve livelihood and reduce water pollution Vietnamese. is to protect the fishpond aquaculture industry which is a source of diversified income for farmers in the Mekong delta by treating the waste water and solids from fish ponds, whilst at the. wastewater and solids from fishponds before discharge to reduce water pollution; e Develop resource recovery and re-use strategies for waste water and solids from fish ponds including land