Low Treatment Technology Research Articles

Producing Class A Biosolids with Low-Cost, Low-Technology Treatment Processes

Class A biosolids can be produced using low-cost, low-technology biosolids treatment processes including lagoon storage, air drying, and cake storage. This project reviewed the available literature and municipal agency data about these processes. This report presents design and operating guidelines distilled from the review process. It is designed for wastewater treatment plant (WWTP) managers, operators, and engineers who wish to discern whether these processes, used alone or in combination, might be practically applied at specific plants. This report also describes the U.S. regulatory environment in relation to producing Class A biosolids and defining Class A processes. It also presents a list of recommended research needs. This title belongs to WERF Research Report Series ISBN: 9781780404288 (eBook) ISBN: 9781843396932 (Print)

Low-technology assisted reproduction and the risk of preterm birth in a hospital-based cohort

To estimate the risk of preterm birth in singleton infants conceived through low-technology assisted reproduction (intrauterine insemination and/or ovulation induction/stimulation). Hospital-based cohort study. University-affiliated hospital. Singleton babies born between 2001 and 2007 to 16,712 couples with no reported infertility (reference category), 378 babies conceived with low-technology treatment; 437 conceived with high-technology treatment; and 620 conceived naturally after a period of infertility. None. Treatment data were obtained from couples undergoing standard infertility investigation and care. Preterm birth, defined at three clinical endpoints: <37, <35, and <32 weeks of completed gestation. After adjustment for age, parity, education, smoking, alcohol/drug use, and body mass index, the risk ratios and 95% confidence intervals (CI) of preterm birth for low technology were: 1.49 (CI: 1.12-2.00); 2.02 (CI: 1.30-3.13); and 2.93 (CI: 1.63-5.26) at <37, <35, and <32 weeks gestation, respectively, not dissimilar from the estimates for in vitro fertilization. Restricting the analysis to primiparas strengthened the association between treatment and preterm birth at the lower gestational endpoints. The increased risk persisted when the untreated group was used as the reference category, although the estimates were attenuated. In this large hospital-based cohort study, low-technology assisted reproduction appeared to be a moderately strong predictor of preterm birth, with similar associations observed in the high-technology treatment group. After adjusting for confounders, as well as the shared characteristics of infertile couples, associations were attenuated but remained significant, suggesting that part of the risk is likely attributable to the treatment.

Recycling of organic wastes using locally isolated lignocellulolytic strains and sustainable technology

The magnitude and nature of the waste generated across different borders have prompted the need for an appraisal of the conventional method of waste collection and the landfill or incineration that are unsustainable due to their high cost and impact on the environment and public health. This study focuses on the recycling of organic wastes (food waste and yard trimmings) using four isolated fungal strains in an experimental setup that simulates sustainable low-technology treatment for the production compost. Separated food and yard trimmings were composted using Phanerochaete chrysosporium, Lentinus tigrinus, Aspergillus niger and Penicillium sp. in two adopted systems (open and closed) based on a solid-state bioconversion process. The results were obtained at p ≤ 0.05 after ten harvests indicating a pH range of 5.68–8.82, an organic weight loss of 11.92 % and a carbon-to-nitrogen (C/N) ratio range of 16.99–18.20 for the open system of the compost. The closed system indicated a relatively lower value of C/N ratio, which is 8.60–13.38 and an organic weight loss of 8.92 % at a pH range of 5.68–7.30. The germination index, ranging between 53–105 and 49–122 %, and the electrical conductivity ranging between 2.57–3.17 and 2.72–2.95 mS/dm for the open and closed systems, respectively, were used to evaluate the toxicity and stability of the compost produced. The technology adopted in this study indicates the viability of the process of the large-scale production of biofertilizer with the C/N ratio of 100 % at harvest.

The Potential of a Low Cost Technology for The Greywater Treatment

Greywater (GW) is household wastewater effluent originating from baths, showers, kitchen and hand wash basins and laundry and constitutes 50-80% of indoor household water use. It represents water that can potentially be intercepted at the household level for use. In Kenya, GW use is practiced on an informal basis to supplement irrigation water, either in urban gardens in middle to upper income suburbs or in food gardens in lower income informal, periurban and rural areas. However, the reuse of greywater for irrigation without any significant pre-treatment poses a potential risk to both human and environmental health due to microbial and chemical contamination. This study investigated the potential of a low cost greywater treatment (GWT) system for safe greywater reuse by households. The system comprises of discrete units of barrels that allows for filtration, flocculation, sedimentation and disinfection. GWT system produced water with both pH and electrical conductivity suitable for irrigation according to WHO guidelines. It was also efficient at eliminating Salmonella sp. and reducing total coli form in composite greywater from households in Homa Bay after the effluent was disinfected with commercial disinfectant, sodium hypochlorite (NaOCl). The cleaned greywater had a total coli form count (2.5x10 6 cfu/100 ml) comparable to 0->2.4 � 10 6 cfu/100 ml obtained when greywater was treated using an expensive biological aerated filter (BAF). Fecal coli form counts (2.1� 10 2 cfu/100 ml) compare well with 10 3 cfu/100 ml provided in WHO guidelines for public parks and crops likely to be eaten uncooked. The treatment had no effect on dissolved oxygen, pH, salinity and electrical conductivity. The study concludes that the GWT system can be a sustainable and promising low cost low technology treatment system that can be run and maintained by unskilled operators.

Treatability by Cryotherapy in a Screen-and-Treat Strategy

We estimated the percentage of women infected with human papillomavirus (HPV+) who cannot be immediately treated with cryotherapy. In a 10,000-woman Costa Rican cohort, we analyzed the 559 HPV+ women aged 25 to 55 years and estimated the proportion for whom immediate cryotherapy was not indicated (i.e., invasive cancer, large precancerous lesions, or benign abnormalities that risk failure such as large ectopy, squamocolumnar junction not visualized, polyps, ulcers, or distorted or atrophied cervix). To determine whether cryotherapy at time of baseline HPV screening would effectively treat HPV+ women, 2 expert gynecologists independently judged entire clinical histories (5-7 years of cytology, histology, and HPV tests) and a full longitudinal series of digitized cervical images. Reviewers judged 144 (25.8%) of 559 HPV+ women as not treatable by immediate cryotherapy. Among 72 women with cervical intraepithelial neoplasia grade 3 who would benefit most from a screening program, 35 (48.6%) were not treatable. In particular, 29 women (40.3%) were determined not treatable for reasons most likely associated with cryotherapy's inadequacy (lesion was large, suspected cancerous or in the endocervical canal or fornix). "Screen-and-treat" programs in low-resource settings will soon use a rapid HPV test to screen older women once or twice in their lifetime, identifying women at higher risk for precancer. Our findings suggest that cryotherapy might not effectively treat many precancers, and other safe, low-technology treatment options could be required, in a scenario where all HPV+ women in this targeted group would receive cryotherapy at the same visit.

An Evaluation by Midwives and Gynecologists of Treatability of Cervical Lesions by Cryotherapy Among Human Papillomavirus-Positive Women

To estimate efficacy of a visual triage of human papillomavirus (HPV)-positive women to either immediate cryotherapy or referral if not treatable (eg, invasive cancer, large precancers). We evaluated visual triage in the HPV-positive women aged 25 to 55 years from the 10,000-woman Guanacaste Cohort Study (n = 552). Twelve Peruvian midwives and 5 international gynecologists assessed treatability by cryotherapy using digitized high-resolution cervical images taken at enrollment. The reference standard of treatability was determined by 2 lead gynecologists from the entire 7-year follow-up of the women. Women diagnosed with histologic cervical intraepithelial neoplasia grade 2 or worse or 5-year persistence of carcinogenic HPV infection were defined as needing treatment. Midwives and gynecologists judged 30.8% and 41.2% of women not treatable by cryotherapy, respectively (P < 0.01). Among 149 women needing treatment, midwives and gynecologists correctly identified 57.5% and 63.8% (P = 0.07 for difference) of 71 women judged not treatable by the lead gynecologists and 77.6% and 59.7% (P < 0.01 for difference) of 78 women judged treatable by cryotherapy. The proportion of women judged not treatable by a reviewer varied widely and ranged from 18.6% to 61.1%. Interrater agreement was poor with mean pairwise overall agreement of 71.4% and 66.3% and kappa's of 0.33 and 0.30 for midwives and gynecologists, respectively. In future "screen-and-treat" cervical cancer prevention programs using HPV testing and cryotherapy, practitioners will visually triage HPV-positive women. The suboptimal performance of visual triage suggests that screen-and-treat programs using cryotherapy might be insufficient for treating precancerous lesions. Improved, low-technology triage methods and/or improved safe and low-technology treatment options are needed.

The effect of various infertility treatments on the risk of preterm birth.

The high incidence of preterm birth (<37 weeks gestation) is a major concern in assisted reproductive technology. The objective of this study was to compare the risk of preterm birth from singleton pregnancies following either low technology treatment (intrauterine insemination and donor insemination) or high technology treatment (IVF, ICSI and gamete intra-Fallopian transfer) with that of naturally conceived pregnancies. Three cohorts of pregnancies resulting from either low or high technology treatment or from natural conception were included in the study. A number of potential risk factors were adjusted for. The incidence of very preterm birth (<32 weeks of gestation) was not significantly increased in the low technology treatment group (1.0 versus 1.3% in controls) but was significantly higher in the high technology treatment group (5.2%, P < 0.001). In spontaneous, elective Caesarean section (CS) and induced delivery onset, the risk of preterm birth increased gradually from the controls to the low technology treatment group to the high technology treatment group, while for an emergency CS the risk of preterm birth was very high in both treatment groups. The overall incidence of preterm birth increased significantly from the controls to the low technology treatment group and to the high technology treatment group. Logistic regression analysis showed that younger and older age, previous perinatal death and emergency CS were associated with an increased risk, while a previous live birth reduced the risk. The length of the infertile period did not seem to affect the risk in any of the treatment groups.

Recycling of treated water in Palestine: Urgency, obstacles and experience to date

To provide piped water to rural areas of Palestine, low technology treatment plants and sewers should be installed at minimum cost and for ease of operation. Treated waters can also be used for irrigation. There should be training for selection of crops, running wastewater plants, recycling and public education for the idea of reuse.

Recycling of treated water in Palestine: Urgency, obstacles and experience to date

To provide piped water to rural areas of Palestine, low technology treatment plants and sewers should be installed at minimum cost and for ease of operation. Treated waters can also be used for irrigation. There should be training for selection of crops, running wastewater plants, recycling and public education for the idea of reuse.

Comprehensive assessment of common musculoskeletal disorders

This article reviews the common musculoskeletal disorders that are likely to be encountered in the women's primary care setting. Basic anatomy and physiology of the musculoskeletal system are reviewed, and the assessment and treatment of complaints of strains, sprains, low back pain, chest pain, carpel tunnel syndrome, musculoskeletal pain syndrome, fibromyalgia, osteoporosis, and osteoarthritis are discussed. Examples of low-technology treatment strategies are included.

Purification Efficiency of Danish Biological Sand Filter Systems

During an investigation in 1989 on small low technology treatment systems, particularly reed bed and biological sand filter systems in Denmark, it appeared that biological sand filter systems offer several advantages for the treatment of small wastewater sources. These observations gave rise to a new project concerning systematic registration of all biological sand filter systems in Denmark. Besides this registration the aim of the project was to indicate the reliability of these systems concerning removal ability and to give some general guidelines on different circumstances which seem to have positive or negative effects on the removal of particularly ammonium and phosphorus. The paper summarizes the results and experiences that have been collected since the beginning of the use of biological sand filter systems in Denmark in the late 70s. Typical purification efficiencies of 90-95% for BI5, 30-45% for nitrogen and 40-60% for phosphorus were observed. The ripening of sand filters to their maximum removal capacity is often short, within a few months, but longer periods of about 6 months may be required to achieve full nitrification. High nitrogen removal depends on the nitrification processes and also of anoxic zones in the filter with denitrification. The best way to achieve good nitrification is to use coarse-grained sand. The removal of phosphorus is indeed affected by the chemical properties of the sand in question. In ferrous enriched sand it is possible to achieve removal efficiencies of 70-90% of the phosphorus at concentrations of 10-15 mg P/l in the inlet.

Experimental Investigations into the Use of Emergent Plants to Treat Sewage in South Africa

South Africa is a relatively water-short country which has many rural communities with water-borne sewage infrastructures requiring low technology treatment facilities. In order to protect the water resources of the country the authorities have set high standards for effluent quality (COD &amp;lt; 75 mg/l, NH3 &amp;lt; 10 mg/l, E. coli &amp;lt; 1000 and in some areas P &amp;lt; 1 mg/l). Traditionally, oxidation ponds have been used in these applications but have not been able to consistently meet the required standards and recently interest has been shown in artificial wetlands as a low technology means of solving the problem. As a result several experimental projects are at present being initiated in South Africa, both as primary and secondary treatment for domestic sewage and also as a tertiary treatment to remove nitrogen, phosphorus and E. coli from conventional sewage plant effluents. The designs of these experimental projects are described in the paper and it is hoped that data will be available for presentation at the seminar.